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Journal articles on the topic '5-trans THF'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Willey, Gerald R., Paul R. Meehan, Timothy J. Woodman, and Michael G. B. Drew. "Identification of the dysprosium(III) chloride solvate DyCl3(THF)3.5: crystal structure of the ion pair [trans-DyCl2(THF)5] [trans-DyCl4(THF)2]." Polyhedron 16, no. 4 (January 1997): 623–27. http://dx.doi.org/10.1016/0277-5387(96)00315-4.

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2

Sobota, Piotr, Jozef Utko, and Slawomir Szafert. "Ionization of YCl3 in Tetrahydrofuran. Crystal Structures of the [trans-YCl2(THF)5][trans-YCl4(THF)2] Salt and Polymeric [YCl3.cntdot.2THF].infin. Compounds." Inorganic Chemistry 33, no. 23 (November 1994): 5203–6. http://dx.doi.org/10.1021/ic00101a011.

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3

Phuphuak, Y., F. Bonnet, G. Stoclet, M. Bria, and P. Zinck. "Isoprene chain shuttling polymerisation between cis and trans regulating catalysts: straightforward access to a new material." Chemical Communications 53, no. 38 (2017): 5330–33. http://dx.doi.org/10.1039/c7cc01016h.

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Isoprene chain shuttling polymerisation between the 1,4-trans regulating Cp*La(BH4)2(THF)2/MgnBuEt (Cp* = C5Me5) and the 1,4-cis regulating NdCl3(THF)2/AlR3 (R = Et or iBu) systems provides access to stereoblock polyisoprene.
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4

Anfang, Stefan, Kurt Dehnicke, and Jörg Magull. "Die Kristallstrukturen der Dysprosium-Komplexe [DyCl3(DME)2] und [DyCl2(THF)5]+[DyCl4(THF)2]- / Crystal Structures of the Dysprosium Complexes [DyCl3(DME)2] and [DyCl2(THF)5]+[DyCl4(THF)2]-." Zeitschrift für Naturforschung B 51, no. 4 (April 1, 1996): 531–35. http://dx.doi.org/10.1515/znb-1996-0416.

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Abstract [DyCl3(DME)2] (DME = 1,2-dimethoxyethane) has been prepared from the known tetrahy-drofuran complex [Dy2Cl6(THF)7] in boiling DME. Both complexes were characterized by structure determinations. [DyCl3(DME)2]: Space group P21/c, Z = 4, lattice dimensions at -70 °C: a = 1141.9(6), b = 884.2(4), c = 1558.3(6) pm, β = 104.83(4)°. The complex has a molecular structure with a distorted pentagonal bipyramidal geometry in which the oxygen atoms of the chelating DME molecules and one chlorine atom occupy the pentagonal plane. [DyCl2(THF)5]+[DyCl4(THF)2]-: Space group C2/c, Z = 4, lattice dimensions at -70 °C: a -1241.4(9), b = 1139.4(6), c = 2735.1(19) pm, β = 91.19(4)°. The complex contains a seven-coordinate cation with axial chloride ligands in a pentagonal bipyramidal structure and a six-coordinate anion with a trans octahedral geometry.
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5

Siewert, Birgit, and Ulrich Müller. "Die Kristallstrukturen von PPh4[AsCl4(THF)2] und PPh4[AsBr4(THF)2] / The Crystal Structures of PPh4[AsCl4(THF)2] and PPh4[AsBr4(THF)2]." Zeitschrift für Naturforschung B 47, no. 5 (May 1, 1992): 680–84. http://dx.doi.org/10.1515/znb-1992-0512.

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In the effort to react W(CO)6 with (PPh4)2[As2Cl8] and Cr(CO)6 with PPh4[As2SBr5] in tetrahydrofurane under UV irradiation the title compounds were obtained as main products. Their crystal structures were determined by X-ray diffraction. PPh4[AsCl4(THF)2], monoclinic, P2/c, Z = 2, a = 881.6(3), b = 809.0(6), c = 2418.6(9) pm, β = 99.44(4)°, R = 0.086 for 1619 observed unique reflexions. PPh4[AsBr4(THF)2], monoclinic, C 2/c, Z = 4, a = 2459.2(5), b = 748.2(3), c = 1784.3(4) pm, β = 94.02(2)°, R = 0.080 for 1513 reflexions. In both compounds ions [AsX4(THF)2]- are located on inversion centers; they have octahedral coordination with trans configuration; the stereochemical activity of the lone electron pairs does not show up in deviations of the bond angles, but in increased bond lengths. The PPh4+ ions are stacked to columns in the b direction.
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6

Morra, Barbora, Nicholas A. Morra, Daniel G. MacDonald, and Brian L. Pagenkopf. "Gram-Scale Synthesis of the Co(nmp)2 Catalyst to Prepare trans-2,5-Disubstituted Tetrahydrofurans by the Aerobic Oxidative Cyclization of Pent-4-en-1-ols." Synthesis 52, no. 06 (January 8, 2020): 847–52. http://dx.doi.org/10.1055/s-0039-1690730.

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Co(nmp)2 is an efficient catalyst for the aerobic oxidative cyclization of pent-4-en-1-ols to give 5-hydroxymethyl trans-tetrahydrofurans (THFs) as single diastereomers in high yield. The trans-THF pharmacophore is of interest because it is found in many biologically active natural products. The three-step synthesis of Co(nmp)2 described here gives the catalyst as a fine powder in 80–85% overall yield on 10-gram scale. The use of the catalyst in a representative oxidative cyclization is also described.
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7

Lindner, Ekkehard, and Berthold Andres. "Notizen: Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XV [1]. (Ether-Phosphan)-stabilisierter cis-Dihydrido-Rhodium(III)-Komplex / Novel Basic Ligands for the Homogenous Catalytic Methanolcarbonylation, XV [1]. (Ether-Phosphane)-Stabilized cis-Dihydrido-rhodium(III) Complex." Zeitschrift für Naturforschung B 43, no. 3 (March 1, 1988): 369–70. http://dx.doi.org/10.1515/znb-1988-0321.

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Reaction of [Rh(NBD)(P∼O)2][SbF6] (1) (NBD = norbornadiene) with hydrogen results in the formation of the stable dihydrido rhodium complex [cis- (2). Rh - O bond cleavage in 2 by carbon monoxide or NaBH4 affords the products [trans-(P∼O)2Rh(CO)3][SbF6] (3) and [trans-H2Rh((P∼O)2(η2-H2BH2)] (5), respectively. Upon treating a THF solution of 3 with argon, 3 eliminates CO to give the complex (4) with a mono- and bidentate (ether-phosphane) ligand.
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8

Trifonov, Alexander A., Mikhail N. Bochkarev, Herbert Schumann, and Sebastian Dechert. "On Attempts to Synthesize Lanthanide Complexes of the Dianionic Fluorenyl-alkoxo Ligand [C13H8-cyclo-C6H10-O]2-. Crystal Structure of (C13H9-cyclo-C6H10-O)LaI2(DME)2." Zeitschrift für Naturforschung B 58, no. 5 (May 1, 2003): 389–94. http://dx.doi.org/10.1515/znb-2003-0506.

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Racemic trans-2-(9(H)-fluoren-9-yl)cyclohexanol, C13H9-cyclo-C6H10-OH (1), reacts with two equivalents of potassium naphthalenide in THF to give the dipotassium salt [C13H8-cyclo-C6H10-O]- K2(THF) (2). Recrystallization of 2 from pyridine affords the solvent free salt [C13H8-cyclo-C6H10- O]K2 (3). The reactions of LaI3(THF)4 with one equivalent of 2 or of YbI2(THF)2 with equimolar amounts of 2 produce the alkoxolanthanum diiodide (C13H9-cyclo-C6H10-O)LaI2(DME)2 (4) and the ytterbium dialkoxide (C13H9-cyclo-C6H10-O)2Yb(THF)0.5(5), respectively. [(Me3Si)2N]3Y reacts with three equivalents of 1 with elimination of hexamethyldisilazane and formation of the yttrium trialkoxide (C13H9-cyclo-C6H10-O)3Y (6). The compounds 2 to 5 were characterized by elemental analyses, 1H NMR, 13C NMR and IR spectra. The molecular structure of 4 was determined by single crystal X-ray diffraction.
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9

Wiberg, Nils, Angelika Wörner, Hans-Wolfram Lerner, Konstantin Karaghiosoff, and Heinrich Nöth. "Supersilylverbindungen des Phosphors, V [1]. Darstellung, Struktur und Reaktivität des Pentaphosphids (tBu3Si)3P5Na2 und des Pentaphosphans (tBu3Si)3P5[2] / Supersilyl Compounds of Phosphorus, V [1]. Preparation, Structure, and Reactivity of the Pentaphosphide (tBu3Si)3P5Na2 and the Pentaphosphane (tBu3Si)3P5 [2]." Zeitschrift für Naturforschung B 53, no. 9 (September 1, 1998): 1004–14. http://dx.doi.org/10.1515/znb-1998-0912.

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The orange THF adduct (tBu3Si)3P5Na2 (THF)4 of the pentaphosphide (tBu3Si)3P5Na2 (3) has been prepared, (i) by protolysis of the tetraphosphide (tBu3Si)2P4Na2(THF)n (2) with CF3CO2H in THF (molar ratio 2 : 1 ) , (ii) by dissolving crystalline 2 in toluene, and (iii) by the reaction of P4 with tBu3SiNa(THF)2 in benzene (molar ratio 1 : 4). According to an X-ray structural analysis, the THF adduct of 3 contains a P3 ring with two PNa(SitBu3) substituents in cis position and one SitBu3 substituent in trans position to the former groups. The protolysis of 3 with CF3CO2H leads to the pentaphosphane P5H2(SitBu3)3 (9), the silylation of 3 with Me2SiCl2 to the pentaphosphane P5 (SiMe2)(SitBu3)3 (10), and the oxidation of 3 with C2(CN)4 to the pentaphosphane P5(SitBu3)3 (5). The structures of 3,5,9, and 10 have been assigned from 31P and 29Si NMR data. The pentaphosphane 5 contains a hitherto unknown P5 backbone of a P3 ring anellated with a P4 ring.
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10

Paul, Ratan Kumar, Md Faruak Ahmad, Mohammad Mizanur Rahman Khan, and Muhammad Younus. "Synthesis and Antibacterial Activities of Sugar-containing Platinum Ethynyl Complexes." Journal of Bangladesh Academy of Sciences 40, no. 1 (June 22, 2016): 65–77. http://dx.doi.org/10.3329/jbas.v40i1.28326.

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New sugar-containing aryl ethynyl ligand [N-(4-trimethylsilylethynylphenyl)-?-D-glucopyranosylamine] 2 has been prepared by the reaction of [N-(4-iodophenyl)-?-D-glucopyranosylamine] 1 with trimethysilylacetylene in the presence of Pd(OAc)2/CuI catalyst, in iPr2NH and DMF solvent mixture. The trimethylsilyl group of compound 2 was deprotected using K2CO3 in methanol to form terminal ethynylene ligand [N-(?-D-glucopyranosyl)aniline-4-ethyne] 3. Novel platinum mono-ethynyl complex trans-[(P(Bu)3)2PtCl(C?C-4-C6H4-NH-D-glocose)] 4 and bis-ethynyl complex trans-[(P(Bu)3)2PtCl(C?C-4-C6H4-NH-D-glocose)2] 5 were formed by the dehydrohalogenation reaction of trans-[Pt(P(Bu)3)2Cl2] with terminal ethynyl ligand 3 in iPr2NH/THF, in the presence of CuI, at 65ºC. The complexes are hygroscopic in air, and are fairly soluble in methanol and CH2Cl2. The new compound 2 - 5 were characterized by FTIR and UV-Vis spectroscopy and elemental analysis. The compounds were tested for antibacterial activity using disk diffusion technique. The platinum complexes 4 and 5 displayed good resistivity against the following bacteria: Escherichia coli, Proteus penneri, Klebsiella oxytoca and Pseudomonas aeruginosa.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 1, 65-77, 2016New sugar-containing aryl ethynyl ligand [N-(4-trimethylsilylethynylphenyl)-?-D-glucopyranosylamine] 2 has been prepared by the reaction of [N-(4-iodophenyl)-?-D-glucopyranosylamine] 1 with trimethysilylacetylene in the presence of Pd(OAc)2/CuI catalyst, in iPr2NH and DMF solvent mixture. The trimethylsilyl group of compound 2 was deprotected using K2CO3in methanol to form terminal ethynylene ligand [N-(?-D-glucopyranosyl)aniline-4-ethyne] 3. Novel platinum mono-ethynyl complex trans-[(P(Bu)3)2PtCl(C?C-4-C6H4-NH-D-glocose)] 4 and bis-ethynyl complex trans-[(P(Bu)3)2PtCl(C?C-4-C6H4-NH-D-glocose)2] 5 were formed by the dehydrohalogenation reaction of trans-[Pt(P(Bu)3)2Cl2] with terminal ethynyl ligand 3 in iPr2NH/THF, in the presence of CuI, at 65ºC. The complexes are hygroscopic in air, and are fairly soluble in methanol and CH2Cl2. The new compound 2 - 5 were characterized by FTIR and UV-Vis spectroscopy and elemental analysis. The compounds were tested for antibacterial activity using disk diffusion technique. The platinum complexes 4 and 5 displayed good resistivity against the following bacteria: Escherichia coli, Proteus penneri, Klebsiella oxytoca and Pseudomonas aeruginosa.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 1, 65-77, 2016
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11

Unger, Gesa, Gerhard Erker, Gerald Kehr, and Roland Fröhlich. "An Internally Coordinated Metalla[14]-crown-5 System with a Pentagonal-dipyramidal Coordination Geometry of the Central Titanium Atom." Zeitschrift für Naturforschung B 59, no. 8 (August 1, 2004): 917–20. http://dx.doi.org/10.1515/znb-2004-0808.

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AbstractTreatment of the dilithiated dibenzotetraethyleneglycol reagent [(o-C6H4OLi)-(OCH2CH2)2O- (o-C6H4OLi)] (5) with TiCl4 · 2 THF gave the corresponding metal complex [{(o-C6H4O-) - (OCH2CH2)2O-(o-C6H4O-)}TiCl2] (6). The X-ray crystal structure analysis of 6 revealed that all five oxygen atoms are located in one plane and bonded to titanium in a pentagonal-dipyramidal geometry with the two chloride ligands being oriented trans to each other in the apical positions.
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12

Wang, Jian, Nicholas A. Morra, Hongda Zhao, Jeffrey ST Gorman, Vincent Lynch, Robert McDonald, John F. Reichwein, and Brian L. Pagenkopf. "Synthesis and first X-ray structures of cobalt(II) and cobalt(III) complexes bearing 2,4-dioxo-alkanoic acid dialkylamide ligands." Canadian Journal of Chemistry 87, no. 1 (January 1, 2009): 328–34. http://dx.doi.org/10.1139/v08-151.

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The aerobic oxidation of 5-hydroxy pentenes to trans-tetrahydrofurans (THFs), the Mukaiyama oxidation, has in recent years emerged as a powerful tool in synthetic chemistry. In this report we describe the first crystal structures of 2,4-dioxo-alkanoic acid dialkylamide complexes for both Co(II) and Co(III) salts. The Co(II) structures show an unprecedented arrangement of atoms, with a central Co(II)(H2O)6 flanked by two Co(II) atoms each coordinated with three anionic chelating ligands. The dimeric Co(III) structures show two anionic chelating ligands and bridging hydroxyl groups.Key words: aerobic oxidation, trans-tetrahydrofuran (THF), cobalt, X-ray crystallography, oxidation, coordination.
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13

Deacon, Glen B., Peter C. Junk, and Aron Urbatsch. "Lanthanoid and Alkaline Earth Complexes Involving New Substituted Pyrazolates." Australian Journal of Chemistry 65, no. 7 (2012): 802. http://dx.doi.org/10.1071/ch12069.

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From the pyrazoles 3,5-di-(2′-furanyl)pyrazole (fu2pzH), 3-phenyl-5-(2′-thienyl)pyrazole (PhtpzH) and 3-(2′-furanyl)-5-(2′′-naphthyl)pyrazole (funappzH), a range of alkaline earth and lanthanoid pyrazolate complexes has been prepared by redox transmetallation/protolysis reactions between free metals, Hg(C6F5)2 and the pyrazoles, by reaction of I2‐activated metals with the pyrazoles, and in one case by a similar reaction of unactivated metal, in the donor solvents tetrahydrofuran (thf) and 1,2-dimethoxyethane (dme). Thus the divalent [Ca(Phtpz)2(thf)4], [Ba(Phtpz)2(thf)4] and [Ca(funappz)2(thf)4]·(thf) complexes, the heteroleptic [Yb(Phtpz)I(thf)4] and the trivalent [La(fu2pz)3(thf)3]·2thf complex have been prepared and structurally characterized, as well as the dme complexes [Yb(Phtpz)2(dme)2] and [Eu(Phtpz)3(dme)2]. Highlights include the first trans-[LnII(pz)I(thf)4] complex, a rare transoid [Ln(pz)2(dme)2] complex and a complex with both chelating and unidentate dme. In all cases, the Phtpz complexes exhibit pronounced positional disorder of the 2-thienyl and phenyl groups in the solid state, as do the two polymorphs of the parent pyrazole.
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14

Deacon, GB, CM Forsyth, WC Patalinghug, AH White, A. Dietrich, and H. Schumann. "Organolanthanoids. XVII. The Synthesis of Bis(diphenylphosphinocyclopentadienyl)ytterbium(II) and Derived Heterobimetallic Complexes [Yb(thf)n(C5H4PPh2)2Z] [Z=Ni(CO)2, Mo(CO)4 or PtMe2; n = 1 or 2; thf = Tetrahydrofuran]. The X-Ray Crystal-Structure of [Yb(thf)2(C5H4PPh2)2Ni(CO)2]." Australian Journal of Chemistry 45, no. 3 (1992): 567. http://dx.doi.org/10.1071/ch9920567.

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Reaction of diphenylphosphinocyclopentadiene with Yb (C6F5)2 or with ytterbium metal and Hg(C6F5)2 in tetrahydrofuran ( thf ) gives, after workup with toluene, the phosphinoytter-bocene , [Yb (C5H4PPh2)2( thf )]. Treatment with thf or with N,N,N′,N′- tetramethylethane-1,2-diamine ( tmen ) yields [ Yb (C5H4PPh2)2L2] (L = thf or L2 = tmen ). Redox trans- metallation between ytterbium metal and Tl (C5H4PPh2) in l,2-dimethoxyethane ( dme ) gives thallium metal and [ Yb (C5H4PPh2)2(dme )]. The ytterbium-transition metal hetero-bimetallics [ Yb ( thf ) (C2H4PPh2)2Z]. nPhMe [Z = Ni(CO)2, Mo(CO)4 or PtMe2, n = 2/3 or 1] have been prepared by reaction of [ Yb ( thf )(C5H4PPh2)2] with Ni(CO)2(PPh3)2, Mo(CO)4( nbd ) ( nbd = norbornadiene ) or PtMe2(cod) (cod = cycloocta-1,5-diene) in toluene. Treatment of the heterobimetallics with tetrahydrofuran [Z = PtMe2 or Mo(CO)4] or a preparation in thf /toluene [Z = Ni(CO)2] yields [ Yb ( thf )2(C5H4PPh2)2PtMe2]. thf, [ Yb ( thf )2(C2H4PPh2)2Mo(CO)4]. thf and [ Yb ( thf )2 (C5H4PPh2)2Ni(CO)2]. The X-ray crystal structure of the last compound (triclinic, space group Pi, a 14.514(5), b 13.565(1), c 10.866(5) 93.11(2), β 104.65(3), γ 97.25(2)�, U 2045 � 3 , Z 2, 5141 data refined to R 0.031) reveals eight-coordinate ytterbium with a pseudo-tetrahedral arrangement of two thf ligands and the cyclopentadienyl ring centroids of two ή5 -diphenylphosphinocyclopentadienide ligands . The latter are also bonded through phosphorus to the Ni(CO)2 group, resulting in tetrahedral stereochemistry for nickel. Infrared spectroscopy suggests the presence of ytterbium- isocarbonyl bonding in solid [ Yb ( thf )(C2H4PPh2)2Z] [Z = Ni(CO)2 or Mo(CO)4].
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15

Deacon, Glen B., Tiecheng Feng, Peter C. Junk, Brian W. Skelton, Alexander N. Sobolev, and Allan H. White. "Preparation and X-Ray Crystal Structures of Tetrahydrofuran-Complexed Rare Earth Chlorides — a Structurally Rich Series." Australian Journal of Chemistry 51, no. 1 (1998): 75. http://dx.doi.org/10.1071/c97174.

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Anhydrous lanthanoid metal chlorides LnCl3(thf)n (Ln = La, Ce, Nd, Sm, n = 2; Ln = Tb, Ho, n = 2·5; Ln = Dy, Tm, n= 2·7; Ln = Gd, Yb, Lu, n = 3; Ln = Er, n = 3·5) have been prepared in excellent yield by the direct reaction of the lanthanoid metal powders with hexachloroethane in tetrahydrofuran (thf), and (Ln = Eu, n = 0·8; Ln = La, n = 1·7; Ln = Pr, n = 2; Ln = Gd, n = 2·5; Ln = Er, n = 3) in good yield except for EuCl3(thf)0·8 from bulk metal. [YbCl3(thf)2]2 was prepared by prolonged treatment of solid YbCl3(thf)3 with pentane. The X-ray crystal structures of [LnC3(thf)2] (Ln = La, Ce or Pr), [LnCl3(thf)3.5] (Ln = Gd or Er), [YbCl3(thf)3] and [LaCl3(thf)(H2O)] have been determined. For [LaCl3(thf)2], a square antiprismatic single-stranded polymer, ... La(-Cl)3(thf)3La(-Cl)3(thf)2 ..., is the first eight-coordinate LnCl3(thf)n complex. The metal is surrounded by two sets of three bridging chlorines and cis thf oxygens. [LnCl3(thf)2] (Ln = Ce, Pr) have seven-coordinate structures with doubly chloride-bridged linear chains, ... LnCl(µ-Cl)3(thf)2LnCl(µ-Cl)2(thf)2 ... where the lanthanoid atom exists in a pentagonal bipyramidal environment, the pentagonal bipyramidal plane being defined by four chloride atoms and one oxygen atom of the thf ligand, and the axial positions being occupied by a chloride and a thf oxygen atom. [LnCl3(thf)3.5] (Ln = Gd, Er) crystallize as discrete ion pairs, [LnCl2(thf)5]+ [LnCl4(thf)2]¯. The lanthanoid atom in the cation displays pentagonal bipyramidal geometry with two apical chloride atoms and five equatorial thf ligands while the anion has quasi-regular octahedral stereochemistry with trans thf ligands. [LaCl3(thf)(H2O)] displays an eight-coordinate two-dimensional polymeric array with six bridging chlorides per lanthanum atom. Far-infrared spectra have been recorded for a number of products and used as a basis for structural proposals, particularly for products with fractional thf.
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16

Sellmann, Dieter, Gerhard Binker, and Falk Knoch. "Ubergangsmetallkomplexe mit Schwefelliganden, XXXIII*/ Transition Metal Complexes with Sulfur Ligands, XXXIII*." Zeitschrift für Naturforschung B 42, no. 10 (October 1, 1987): 1298–306. http://dx.doi.org/10.1515/znb-1987-1015.

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Abstract In order to investigate the specific properties which are associated with metal sulfur cen­ters, the system Ru/S2C6H42- has been studied with respect to the synthesis of new com­plexes and their reactions as well as their structure. cis-(NBu4)(Ru(NO))(PMe4)(S2C6H4)2] reacts with an excess of PMe3 in boiling THF to give the paramagnetic (μeff = 0,96 B. M., 295 K) trans-(NBu4)(Ru(PMe4)2(S2C6H4)2) (I). A plausible intermediate in this reaction is the nitrido complex (NBu4)(Ru(N)(S2C6H4)2) (2) since 2 gives with one equivalent of PMe3 a very labile product which is probably (NBu4)(Ru(N)(PMe4)(S2C6H4)2) (3). but reacts with an excess of PMe3 even at 20 °C to give 1. The Ru(III) complex 1 is easily oxidized by O2 or PhN2BF4 to yield the diamagnetic Ru(IV) species trans-(Ru(PMe3)2(S2C6H4)2) (4). Remarkably, the transformation of 1 into 4 is achieved also by H+ ions, providing a model reaction for the coupled H+-electron transfer which has been discussed for substrate reactions at metal sulfur centers of enzymes. - The reaction of RuCl2(PMe3)4 with S2C6H42- yields [Ru(PMe3)4(S2C6H4)] (5) at 20 °C, even if an excess of S2C6H42- is applied. Upon heating in THF or EtOH, 5 looses one PMe3 ligand to give the 16e -complex [Ru(PMe4)4(S2C6H4)] (6) which rapidly coordinates CO to give [Ru(CO)(PMe4)4(S2C6H4)] (7); '1P NMR indicates a meridional coordination of PMe4 in 7, and consequently CO must be trans to S2C6H42-. 6 reacts also with LiAlH4 to yield a very sensitive hydride complex to which the tentative formula [Ru(H)2(PMe3)2(S2C6H4)] is assigned. All compounds were characterized by elemental analyses and spectroscopic means, the structures of I and 5 were determined by X-ray structure analysis.
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17

Machnitzki, Peter, Othmar Stelzer, and Claudia Landgrafe. "Komplexbildung und Ligandeneigenschaften der Chlormethylchlorphosphane R(Cl)P-CH2-Cl - Molekülstruktur von trans-Cl2Pd[tBu(Cl)P-CH2-Cl]2 / Coordination Chemistry and Ligand Properties of Chloromethylchlorophosphines R(Cl)P-CH2 -Cl - Molecular Structure of trans-Cl2Pd[tBu(Cl)P-CH2 -Cl]2." Zeitschrift für Naturforschung B 52, no. 9 (September 1, 1997): 1103–13. http://dx.doi.org/10.1515/znb-1997-0915.

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Reaction of the chloromethylchlorophosphines R(Cl)P-CH2-Cl (R = Cl, tBu, C6H11, NEt2, NPh2) (L) with C7H8Mo(CO)4 or (CO)5W(Py), (CO)6W and (CO5W(THF) yields the complexes cis-Mo(CO)4L2(2a - 2e) or (CO)5 WL (3a - 3c), respectively, in high yields. The palladium(II) complexes PdCl2L2 (4a - 4c) are obtained on treatment of 1a, 1b and 1e with 1,5-cyclooctadiene palladium(II) chloride or anhydrous palladium(II) chloride in a homogeneous or heterogeneous reaction, respectively. 4a - 4c are formed as a mixture of cis- and trans-isomers. The 13C {1H} NMR and 1H NMR spectra of 2a - 4c have been analysed, the trans-structure of 4c could be assigned to the predominant isomer. The X-ray structural analysis of 4c (triclinic, space group Pl̅) reveals a trans-square planar coordination at palladium with an antiperiplanar arrangement of the bulky tBu substituents at the phosphorus atoms. Electronic (ƩXiMo) and steric ligand parameters (θ) are given for the chloromethylchlorophosphines R(Cl)P-CH2-Cl (R = Cl, tBu, C6H11, NEt2, NPh2).
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18

Lindner, Ekkehard, and Hubert Norz. "Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XXIV [1]. Rhodium-Komplexe mit (Ether-Phosphan)-Liganden unterschiedlicher Basizität und ihr Einfluß bei der Methylwanderung / Novel Basic Ligands for the Homogenous Catalytic Methanol Carbonylation, XXIV [1]. Rhodium Complexes with (Ether-Phosphane) Ligands of Different Basicity and their Influence on the Methyl Migration." Zeitschrift für Naturforschung B 44, no. 12 (December 1, 1989): 1493–98. http://dx.doi.org/10.1515/znb-1989-1204.

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[(COD)Rh(Cl)(P1∼O)] (3) is obtained from [µ-ClRh(COD)]2 (1) and the (ether-phosphane) ligand P1∼O (2) [P1∼O = Ph2PCH2CH2OCH3]. 3 reacts with AgSbF6 to form the cationic η2-Pl͡ O rhodium complex [(COD)Rh(P1 ͡ O)][SbF6] (4). Addition of another ligand P2∼O (5) [P2∼O = Pr2PCH2C4H7O] to 4 affords the bis(ether-phosphane)rhodium complex[(COD)Rh(P1∼O)(P2∼O)][SbF6] (6) with two different ether-phosphanes. In 6 COD is displaced by CO to give [trans-(P1∼O)(P2∼O)Rh(CO)3][SbF6] (7). The 31Ρ{1H} NMR spectrum of 7 shows a temperature dependence. When a THF solution of compound 7 is flushed with argon it undergoes elimination of carbon monoxide to form [trans-(P1∼O)(P2 ͡ O)Rh(CO)][SbF6] (10), containing a bidentate coordinated P2∼O ligand (5). The reaction is reversible. Oxidative addition of CH3I to 10 results in the formation of a 1:1 mixture of the acyl complexes [cis-(P1 ͡ O)(P2͡ O)Rh(I)(C(0)CH3)][SbF6] (8) and [cis-(P1͡ O)(P2͡ O)Rh(I)(C(O)CH3)][SbF6] (9), the reactive intermediate [trans-(P1∼O)(P2͡ O)Rh(I)(CH3)(CO)][SbF6] (11) not being observed. Formation of either 8 or 9 depends on the S or R configuration of the asymmetric C-atom in 5. On cleaving one or two Rh–O bonds the back reaction to 7 occurs.
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19

Deacon, GB, T. Feng, P. Mackinnon, RH Newnham, S. Nickel, BW Skelton, and AH White. "Organoamido- and Aryloxo-Lanthanoids. V. Preparations of Low-Coordinate Lanthanoid(II) Phenolates, Ln (OC6H2But2-2,6-X-4)2( thf )n (Ln = Yb or Eu; X = H, Me or BuT; N = 2 or 3) and the X-Ray Crystal Structure of Five-Coordinate [Yb (OC6H2But2-2,6-X-4)2( thf )3].thf." Australian Journal of Chemistry 46, no. 3 (1993): 387. http://dx.doi.org/10.1071/ch9930387.

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Lanthanoid (II) complexes of bulky aryl oxides, Ln (OC6H2But2-2,6-X-4)2 ( Ln = Yb or Eu ; X = H, Me or But) have been prepared by one or more of the following methods: ( i ) reaction of Ln (C6F5)2 with the appropriate phenol, (ii) reaction of the lanthanoid metal, Hg(C6F5)2 and the phenol, and (iii) reaction of the lanthanoid metal with the corresponding thallium(I) phenolate, in tetrahydrofuran ( thf ), and they have been isolated as Ln (OC6H2But2-2,6-X-4)2(thf)3 complexes. Crystallization of Yb (OC6H2But2-2,6-X-4)2( thf )3 (X = H or Me) from toluene yields Yb (OC6H2But2-2,6-X-4)2( thf )2. The X-ray crystal structure of [ Yb (OC6H2But3-2,4,6)2( thf )3]. thf [monoclinic, a 10.20(1), b 32.97(2), c 16.018(4) Ǻ, β 93.52(8)°, V 5375 Ǻ3, Z 4, 2734 'observed' data refined to R 0.070] shows distorted square pyramidal five coordination for ytterbium with an apical thf oxygen [ Yb -O 2.44(1)Ǻ], and transoid phenolate oxygens [ Yb -O 2.21(1), 2.22(1)Ǻ, O- Yb -O 149.0(6)°] and trans thf oxygens [ Yb -O 2.47(2), 2.48(1)Ǻ, O-Yb -O 177.3(5)°] in the square plane. Four methyl groups ( Yb…C 3.89-4.15 Ǻ) across the square plane away from the apical oxygen may block coordination of an additional ligand. X-Ray structures of Yb (OC6H2But2-2,6-Me-4)2(thf)n showing four coordination (n = 2) and five coordination (n = 3), given in a preliminary communication,1 are further discussed.
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20

Westerhausen, Matthias, and Wolfgang Schwarz. "Calcium-bis[N,N'-bis(trimethylsilyl)benzamidinat]-THF (1/2) - Synthese, spektroskopische Charakterisierung und Struktur/Calcium-bis[N,N'-bis(trimethylsilyl)benzamidinate]-THF (1/2) - Syntheses, Spectroscopic Characterization and Structure." Zeitschrift für Naturforschung B 47, no. 4 (April 1, 1992): 453–59. http://dx.doi.org/10.1515/znb-1992-0401.

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The reaction of calcium-bis[bis(trimethylsilyl)amide]-THF (1/2) with benzonitrile in THF nearly quantitatively yields the title compound calcium-bis[N,N'-bis(trimethylsilyl)- benzamidinate]-THF (1/2). Under similar conditions pivalonitrile substitutes an ether ligand of calcium-bis[bis(trimethylsilyl)amide]-DME (1/2) without the formation of the corresponding amidinate derivative. The calcium-di(benzamidinate) [H5C6-C(NSiMe3)2]2Ca · 2THF crystallizes in the space group Pbcn with {a = 188.8(6); b = 1286.0(3); c = 1802.5(5) pm; Z = 4}. The calcium atom is hexa-coordinate with a distorted octahedral trans-configuration and with Ca - O and Ca - N bond distances of 238 and 243 pm, respectively. The bond lengths within the NCN moiety with values of 132 pm are characteristic of a diazaallylic system. The short N - Si bond lengths of about 170.5 pm as well as the high field shift of the 29Si{1H} NMR signal are evidence for an effective backdonation of the anionic charge from the nitrogen to the silicon atoms.
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21

Filippou, Alexander Constantin, and Walter Grünleitner. "Ein neuer Weg zu cyclopentadienyl-substituierten Diethylaminocarbin-Komplexen des Wolframs / A New Route to Cyclopentadienyl-Substituted Diethylaminocarbyne Complexes of Tungsten." Zeitschrift für Naturforschung B 44, no. 12 (December 1, 1989): 1572–80. http://dx.doi.org/10.1515/znb-1989-1217.

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We have developed a new, large scale, high yield synthesis of cyclopentadienyl-substituted tungsten diethylaminocarbyne complexes. In the first step an almost quantitative conversion of (η5-C5H5)W(CO)3I (1) and (η5-C5Me5)W(CO)3I (2) using EtNC and Me3NO occurs to give an isomeric mixture of cis and trans (η5-C5H5)W(CO)2(EtNC)I (3 a, 3b) and cis and trans (η5-C5Me5)W(CO)2(EtNC)I (4a, 4b), respectively. The isomeric mixtures of 3a and 3b and 4a and 4b are then quantitatively transformed with sodium powder in THF into the highly reactive, anionic isocyanide complexes Na[η(5-C5H5)W(CO)2(EtNC)] (5) and Na[(η5-C5Me5)W(CO)2(EtNC)] (6). Finally, alkylation of the strong nucleophiles 5 and 6 with Et3OBF4 occurs on the isocyanide nitrogen and yields the low-valent tungsten diethylaminocarbyne complexes (η5-C5H5)(CO)2W≡CNEt2 (7) and (η5-C5Me5)(CO)2W≡CNEt2 (8). Oxidative decarbonylation of 7 and 8 with iodine in CH2C12 gives the high-valent tungsten compounds (η5-C5H5)(I)2(CO)W≡CNEt2 (9) and (η5-C5Me5)(I)2(CO)W≡CNEt2 (10). 9 and 10 are subsequently converted with one equivalent of EtNC and TlPF6 into the cationic carbyne complexes [(η5-C5H5)(I)(EtNC)(CO)W≡CNEt2]PF6 (11) and [(η5-C5Me5)(I)(EtNC)(CO)W≡CNEt2]PF6 (12). Advantages of this route to low- and high-valent tungsten diethylaminocarbyne complexes are discussed in comparison to the classical Fischer procedure using the carbyne complex trans-I(CO)4W≡CNEt2 as precursor.
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22

Rousseau, Lidie, Alexandre Desaintjean, Paul Knochel, and Guillaume Lefèvre. "Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and Mechanistic Investigations." Molecules 25, no. 3 (February 7, 2020): 723. http://dx.doi.org/10.3390/molecules25030723.

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Various substituted bis-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl2 in THF at −5 °C within 2 h. These bis-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)3 with various functionalized alkenyl iodides and bromides in 1 h at 25 °C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic 1H-NMR, which identified the key role of tris-coordinated ate-iron(II) species in the catalytic process.
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23

Engelhardt, LM, BN Figgis, AN Sobolev, and PA Reynolds. "Structures of Some Complexes Containing the ReIVCl4 Unit." Australian Journal of Chemistry 49, no. 4 (1996): 489. http://dx.doi.org/10.1071/ch9960489.

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The X-ray crystal structure determinations of five complexes of rhenium(IV) containing the ReCl4L2 unit, with L monodentate , are reported, one at 92 K. They are: (1) cis -( HNCMeNHPh )2ReCl4, Pccn , a 21.677(4), b 7.253(1), c 12.470(2) Ǻ, R1(2σ) 0.0217, Rw 0.0473; (2) the di ( acetonitrile ) solvate of (1), Pī , a 10.005(2), b 12.120(2), c 12.744(2) Ǻ, α 72.19(1), β 67.65(1), γ 90.95(1)°, R1(2σ) 0.0311, Rw 0.0819; (3) cis -(HN= CMeNH (p-C6H4Me))2ReCl4, Pna21, a 12.782(2), b 8.237(1), c 21.279(3) Ǻ, R1(2σ) 0.0497, Rw 0.1066; (4) cis-( thf )2ReCl4, P 212121, a 7.785(2), b 12.666(4), c 14.253(5) Ǻ, R1(2σ), 0.0326, Rw 0.0827; and (5) trans-(Me2PhP)2ReCl4, P 21/c, a 9.701(2), b 13.739(6), c 8.324(2) Ǻ, β 106.83(2), R1(2σ) 0.0241, Rw 0.0613. The Re-Cl bond lengths in these and six other ReIVCl4L2 octahedral complexes are compared, and no distinct trans-effect of the donor atom on the chlorine atoms is seen either where L is monodentate as in our compounds or where L2 is a chelate ligand, as in the examples from the literature, although the results are much less clear there.
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24

Burdzinski, G. T., M. H. Chisholm, P. T. Chou, Y. H. Chou, F. Feil, J. C. Gallucci, Y. Ghosh, et al. "The remarkable influence of M2δ to thienyl π conjugation in oligothiophenes incorporating MM quadruple bonds." Proceedings of the National Academy of Sciences 105, no. 40 (October 1, 2008): 15247–52. http://dx.doi.org/10.1073/pnas.0807411105.

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Oligothiophenes incorporating MM quadruple bonds have been prepared from the reactions between Mo2(TiPB)4 (TiPB = 2,4,6-triisopropyl benzoate) and 3′,4′-dihexyl-2,2′-:5′,2″-terthiophene-5,5″-dicarboxylic acid. The oligomers of empirical formula Mo2(TiPB)2(O2C(Th)-C4(n-hexyl)2S-(Th)CO2) are soluble in THF and form thin films with spin-coating (Th = thiophene). The reactions between Mo2(TiPB)4 and 2-thienylcarboxylic acid (Th-H), 2,2′-bithiophene-5-carboxylic acid (BTh-H), and (2,2′:5′,2″-terthiophene)-5-carboxylic acid (TTh-H) yield compounds of formula trans-Mo2(TiPB)2L2, where L = Th, BTh, and TTh (the corresponding thienylcarboxylate), and these compounds are considered as models for the aforementioned oligomers. In all cases, the thienyl groups are substituted or coupled at the 2,5 positions. Based on the x-ray analysis, the molecular structure of trans-Mo2(TiPB)2(BTh)2 reveals an extended Lπ-M2δ-Lπ conjugation. Calculations of the electronic structures on model compounds, in which the TiPB are substituted by formate ligands, reveal that the HOMO is mainly attributed to the M2δ orbital, which is stabilized by back-bonding to one of the thienylcarboxylate π* combinations, and the LUMO is an in-phase combination of the thienylcarboxylate π* orbitals. The compounds and the oligomers are intensely colored due to M2δ–thienyl carboxylate π* charge transfer transitions that fall in the visible region of the spectrum. For the molybdenum complexes and their oligomers, the photophysical properties have been studied by steady-state absorption spectroscopy and emission spectroscopy, together with time-resolved emission and transient absorption for the determination of relaxation dynamics. Remarkably, THF solutions the molybdenum complexes show room-temperature dual emission, fluorescence and phosphorescence, originating mainly from 1MLCT and 3MM(δδ*) states, respectively. With increasing number of thienyl rings from 1 to 3, the observed lifetimes of the 1MLCT state increase from 4 to 12 ps, while the phosphorescence lifetimes are ≈80 μs. The oligomers show similar photophysical properties as the corresponding monomers in THF but have notably longer-lived triplet states, ≈200 μs in thin films. These results, when compared with metallated oligothiophenes of the later transition elements, reveal that M2δ–thienyl π conjugation leads to a very small energy gap between the 1MLCT and 3MLCT states of <0.6 eV.
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25

Karst, Andreas, Burkhardt Broschk, Joseph Grobe, and Duc Le Van. "Neue Phospha- und Arsa-Heterocyclen aus Cyclophosphanen bzw. -arsanen (ECF3)n (E = P, As; n = 4, 5) und 1,3-Dienen / Novel Phospha- and Arsa-Heterocycles from Cyclophosphanes or -arsanes (ECF3)n (E = P, As; n = 4, 5) and 1,3-Dienes." Zeitschrift für Naturforschung B 50, no. 2 (February 1, 1995): 189–95. http://dx.doi.org/10.1515/znb-1995-0205.

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Reaction of the cyclotetraphosphane (PCF3)4 or of a mixture of (PCF3)4 and (PCF3)5 with 2,3-dimethyl-1,3-butadiene or isoprene at 25 °C leads to the [4 + 2]-cycloadducts of bis(trifluoromethyl) diphosphene and the phospholene derivatives 2a and 2b, respectively, in the molar ratio diphosphinine/phospholene = 1/2. The analogous reactions of the cycloarsanes (AsCF3)4,5 give the Diels/Alder compounds 4 and 5 of bis(trifluoromethyl)diarsene in 90% yield without arsolene formation. Cyclopentadiene, 1,3-cyclohexadiene and cis or trans piperylene do not react with (AsCF3)4,5, up to temperatures of 60 °C. However, the corresponding [4 + 2]-cycloadducts 6 - 8 are produced by irradiation of the reaction mixture with UV light. The novel phospholenes 2a and 2b as well as the diarsinines 4 - 8 have been characterized by spectroscopic data (MS, NMR, IR). 2a was coordinated as a phosphane ligand to the pentacarbonylchromium fragment by reaction with the photochemically generated complex Cr(CO)5 · THF to afford the new compound (3).
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26

Gebauer, Thorsten, Gerlinde Frenzen, and Kurt Dehnicke. "Synthese und Kristallstrukturen der Palladium(II)-Komplexe cis- und trans-PdCl2[P(OSiMe3)3]2, {PdCl[PO(OSiMe3)2][P(OSiMe3)3]2} und (NMe2H2)2{Pd2Cl4[P4O5(OSiMe3)4]} / Synthesis und Crystal Structures of the Palladium(II) Complexes cis- and trans-PdCl2[P(OSiMe3)3]2, {PdCl[PO(OSiMe3)2][P(OSiMe3)3]2} and (NMe2H2)2{Pd2Cl4[P4O5(OSiMe3)4]}." Zeitschrift für Naturforschung B 48, no. 11 (November 1, 1993): 1661–71. http://dx.doi.org/10.1515/znb-1993-1126.

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The molecular complex PdCl2[P(OSiMe3)3]2 was obtained both as cis- (la) and trans- (lb) isomer from palladium(II) chloride with the equivalent amount of tris(trimethylsilyl)phosphite in a THF suspension at room temperature. With excess P(OSiMe3)3 the complex {PdCI[PO(OSiMe3)2][P(OSiMe3)3]2} (2) is formed with elimination of trimethylchlorosilane. By partial hydrolysis the anionic binuclear palladium complex(NMe2H2)2{Pd2Cl4[P4O5(OSiMe3)4]} (3) is generated from palladium(II) chloride and excess P(OSiMe3)3 in THF in the presence of dimethylamine. All complexes form colourless, moisture-sensitive crystals, which were characterized by X-ray structure determinations.1a: Space group C2/c, Z = 4,2973 observed unique reflections, R = 0.044. Lattice dimensions at —80°C: a =1052.9(2), b =1675.3(5), c = 2240.1(7) pm, β = 99.88(2)°. The compound has a molecular structure with cis-arrangement of the P(OSiMe3)3 groups with Pd—P bond lengths of 222.9 pm.1b: Space group P1̄, Z = 1, 3796 observed unique reflections, R = 0.053. Lattice dimensions at-70°C: a = 959.5(2), b = 998.3(2), c =1162.6(2) pm, α=86.99(3)°, β = 81.63(3)°, γ = 62.91(3)°. The compound has a molecular structure with trans-arrangement of the P(OSiMe3)3 groups with Pd—P bond lengths of 230.4 pm.2: Space group P212121, Z = 4,4444 observed unique reflections, R = 0.055. Lattice dimensions at —70°C: a =1050.0(2), b = 2090.5(3), c = 2357.8(6) pm. The complex has a molecular structure with trans-arrangement of the P(OSiMe3)3 groups with Pd — P bond lengths of 233.6 and 232.1 pm. The Pd—P bond length of the [PO(OSiMe3)2]- ligand is 224.8 pm.3: Space group P1̄, Z = 2,4762 observed unique reflections, R = 0.071. Lattice dimensions at —80°C: a = 1169.3(6), b = 1299.6(6), c = 1641.7(12) pm, α = 69.19(4)°, β = 87.37(5)°, γ = 80.01(4)°. In the dimeric anion {Pd2Cl4[P4O5(OSiMe3)4]}2- the two cis-PdCl2 units are bridged by the four phosphorus atoms of the [P4O5(OSiMe33)4]2- ligand with average Pd— P bond lengths of 221.5 pm.
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27

Schmid, Raimund, and Joachim Strähle. "Synthese und Struktur von 1,5-Bis(tolyl)pentaazadienidokomplexen von Eisen(II) und Ruthenium(I): [Fe(tolN5tol)2]2 und [Ru(CO)3(tolN5tol)]2 / Synthesis and Structure of 1,5-Bis(tolyl)pentaazadienido Complexes of Iron(II) and Ruthenium(I): [Fe(tolN5tol)2]2 and [Ru(CO)3(tolN5tol)]2." Zeitschrift für Naturforschung B 43, no. 5 (May 1, 1988): 533–39. http://dx.doi.org/10.1515/znb-1988-0508.

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The reaction of Fe(CO)4I2 with Ag(tolN5tol) in THF yields dark violet, oxygen sensitive [Fe(tolN5tol)2]2 (1), whereas in the case of Ru(CO)4I2 the reaction with Ag(tolN5tol) occurs under reduction to Ru(I), and brownish, air stable [Ru(CO)3(tolN5tol)]2 (2) is obtained.1 crystallizes from THF as 1·THF in the monoclinic space group P21/c with a = 1395.7(4), b = 2226.5(9), c = 1973.5(7) pm. β = 105.10(2)°, Z = 4. In the binuclear complex four pentaazadienido anions act as (N1,N3)-η2, (N5)-η1 bridging ligands coordinating the Fe atoms octahedrally. 2 forms triclinic crystals with the space group P1̄ and a = 1368.6(6), b = 1393.7(6), c = 1076.1(5) pm, α = 104.59(4)°, β = 107.36(4)°, γ = 73.90(3)°, Z = 2. Two pentaazadienido ligands bridge two Ru(CO)3+ units with their atoms N1 and N3. In addition, the Ru atoms are connected by a Ru-Ru single bond of 267.5 pm. In 1 as well as in 2 the pentaazadienido ligands exhibit planar N5 zigzag chains in the all-trans configuration. The N -N-distances are in the range of 124.2 to 137.4 pm.
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28

Deacon, Glen B., Tiecheng Feng, Peter C. Junk, Gerd Meyer, Natalie M. Scott, Brian W. Skelton, and Allan H. White. "Structural Variety in Solvated Lanthanoid(III ) Halide Complexes." Australian Journal of Chemistry 53, no. 10 (2000): 853. http://dx.doi.org/10.1071/ch00117.

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Treatment of lanthanum metal with CH2Br2 or CH2I2 in tetrahydrofuran (thf) under ultrasound conditions yields the corresponding [LaX3(thf)4] (X = Br, I) complexes in good yield. Recrystallization of [LaBr3(thf)4] from 1,2-dimethoxyethane (dme) or bis(2-methoxyethyl) ether (diglyme) generates [LaBr2(µ-Br)(dme)2]2 and [LaBr2(dig-lyme)2][LaBr4(diglyme)]. Treatment of lanthanoid metals with hexachloroethane in dme yields [LnCl3(dme)2] (Ln = La, Nd, Er or Yb) and in acetonitrile [YbCl2(MeCN)5]2[YbCl3(MeCN)(-Cl)2YbCl3(MeCN)]. The reaction of Yb metal pieces with 1,2-dibromoethane in thf and dme gave single crystals of [YbBr3(thf)3] and [YbBr3(dme)2], respectively. The X-ray determined structure of [LaBr3(thf)4] shows a seven-coordinate monomer with pentagonal-bipyramidal stereochemistry and apical bromide ligands. For [YbBr3(thf)3], a monomeric structure with mer-octa-hedral stereochemistry is observed. In [LaBr2(µ-Br)(dme)2]2, two eight-coordinate La centres are linked by two bridging bromides. The dme ligands have a trans relationship to each other, and cis terminal bromides are transoid to the bridging bromides with dodecahedral stereochemistry for La. By contrast, the 1: 1.5 diglyme adduct is found to be ionic [LaBr2(diglyme)2][LaBr4(diglyme)], with an eight-coordinate bicapped trigonal-prismatic lanthanum cation and a seven-coordinate pentagonal-bipyramidal lanthanum anion. In the cation, the bromide ligands are cis to each other, and in the anion, two bromides are equatorial and two are axial. In [YbBr3(dme)2], [YbCl3(dme)2] and [ErCl3(dme)2], a seven-coordinate pentagonal-bipyramidal arrangement exists with apical halogen ligands. Far-infrared data, and in particular the absence of absorptions attributable to Ì(La–Clter), suggest that [LaCl3(dme)] is polymeric with six bridging chlorides per lanthanum. For [YbCl2(MeCN)5]2[YbCl3(MeCN)(-Cl)2YbCl3-(MeCN)], a remarkable ionic structure, with pentagonal-bipyramidal [YbCl2(MeCN)5]+ cations and octahedral di-nuclear [YbCl3(MeCN)(-Cl)2YbCl3(MeCN)]2– counter ions, is observed. In the former, chloride ligands are apical, while the MeCN ligands of the latter are transoid.
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29

Swidersky, Hans-Walter, Jürgen Pebler, Kurt Dehnicke, and Dieter Fenske. "Acetylenkomplexe von Rhenium(+ VI). Die Kristallstrukturen von [ReCl4(n-C3H7 – C= C – n-C3H7)(POCl3)] und ReCl4(THF)2 / Alkyne Complexes of Rhenium(+VI). The Crystal Structures of [ReCl4(n-C3H7 – C= C – n-C3H7)(POCl3)] and ReCl4(THF)2." Zeitschrift für Naturforschung B 45, no. 9 (September 1, 1990): 1227–34. http://dx.doi.org/10.1515/znb-1990-0902.

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The results of the magnetic susceptibility measurements of the previously reported rhenium alkyne complexes [ReCl4(PhC≡CPh)]2.2 CH2Cl2 and [ReCl4(PhC=CPh)(CH3CN)] in the temperature range of 4.2-293 K suggest d1-configurations, corresponding with oxidation state +VI for the rhenium atoms. The new alkyne complex [ReCl4(n-C3H7–C=C–n-C3H7)(POCl3)] has been prepared by the reaction of ReCl5·OPCl3 with n-C3H7-C≡C–n-C3H7 in CCl4 solution, forming dark red single crystals, which were characterized by IR spectroscopy as well as by a crystal structure determination with X-ray methods (space group P2,/c, Z = 4, 3235 observed unique reflexions, R = 0.026; lattice dimensions at –70 °C: a = 805.6(2), b = 1000.6(4), c = 2188.8(6) pm, β = 79.59(2)°). [ReCl4(n-C3H7-C=C–n-C3H7)(POCl3)] has a molecular structure with the alkyne ligand bonded side-on (bond lengths Re-C 198.4 and 198.2(5) pm). The oxygen atom of the solvating POCl3 molecule is coordinated in trans position to the ReC2 unit of the alkyne ligand (bond length Re—O = 223.7(3) pm).In THF solutions the alkyne complexes of this type undergo a slow reaction forming ReCl4(THF)2, which was also characterized by IR spectroscopy and a crystal structure determination (space group P212121, Z = 4, 2243 observed unique reflexions, R = 0.053; lattice dimensions at –70 °C: a = 773.0(14), b = 1267.1(6), c = 1398.6(7) pm). In ReCl4(THF)2 the THF molecules coordinate in cis-position (bond lengths Re–O 208 and 212(1) pm).
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30

Hackfort, Thorsten, Beate Neumann, Hans-Georg Stammler, and Dietmar Kuck. "A cyclopenta[hi]acephenanthrylene bearing two benzoannelated [3.3.3]propellane units: extension of triptindane chemistry." Canadian Journal of Chemistry 95, no. 4 (April 2017): 390–98. http://dx.doi.org/10.1139/cjc-2016-0498.

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The McMurry reaction of triptindan-9-one (2), a three-fold benzoannelated Cs-symmetrical [3.3.3]propellane ketone, gave trans-9,9′-bitriptindanylidene (5), a sterically crowded stilbene hydrocarbon bearing two E-oriented triptindane moieties, in good yield. Photoisomerization of 5 generated the corresponding cis-stilbene 8 in a photostationary E:Z mixture (55:45), which adopts a similarly crowded C2-symmetrical conformation that is apparently static on the NMR timescale. Photocyclodehydrogenation of 5 via 8 in benzene solution afforded the title hydrocarbon 6, a 1,2,9,10-tetrahydrocyclopenta[hi]acephenanthrylene merged with two triptindane units, in 85% yield. X-ray structure analysis of 6 revealed an essentially planar phenanthrene unit but significant steric repulsion between the pairs of opposite methylene groups of the [3.3.3]propellane cores, giving rise to a C2-symmetrical conformation. Reaction of 2 under modified McMurry conditions (DME instead of THF as a solvent) gave the saturated dimer, 9,9′-bitriptindanyl 7, as a mixture of diastereomers. Attempts to synthesize “columnene” (4), an elusive barrelene derivative fused with two triptindane caps, by three-fold McMurry reaction of triptindane-9,10,11-trione (3) failed.
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31

Gajecki, Leah, Brendan Twamley, and David J. Berg. "Synthesis and crystal structures of tetrameric [2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]sodium and tris[2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]ytterbium(III)." Acta Crystallographica Section E Crystallographic Communications 76, no. 5 (April 21, 2020): 703–9. http://dx.doi.org/10.1107/s2056989020005034.

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Reaction of 2-(4,4-dimethyl-2-oxazolin-2-yl)aniline (H2-L1) with one equivalent of Na[N(SiMe3)2] in toluene afforded pale-yellow crystals of tetrameric poly[bis[μ3-2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido][μ2-2-(4,4-dimethyl-2-oxazolin-2-yl)aniline]tetrasodium(I)], [Na4(C11H13N2O)4] n or [Na4(H-L1)4] n (2), in excellent yield. Subsequent reaction of [Na4(H-L1)4] n (2) with 1.33 equivalents of anhydrous YbCl3 in a 50:50 mixture of toluene–THF afforded yellow crystals of tris[2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido]ytterbium(III), [Yb(C11H13N2O)3] or Yb(H-L1)3 (3) in moderate yield. Direct reaction of three equivalents of 2-(4′,4′-dimethyl-2′-oxazolinyl)aniline (H2-L1) with Yb[N(SiMe3)2]3 in toluene resulted in elimination of hexamethyldisilazane, HN(SiMe3)2, and produced Yb(H-L1)3 (3) in excellent yield. The structure of 2 consists of tetrameric Na4(H-L1)4 subunits in which each Na+ cation is bound to two H-L1 bridging bidentate ligands and these subunits are connected into a polymeric chain by two of the four oxazoline O atoms bridging to Na+ cations in the adjacent tetramer. This results in two 4-coordinate and two 5-coordinate Na+ cations within each tetrameric unit. The structure of 3 consists of a distorted octahedron where the bite angle of ligand L1 ranges between 74.72 (11) and 77.79 (11) degrees. The oxazoline (and anilide) N atoms occupy meridional sites such that for one ligand an anilide nitrogen is trans to an oxazoline nitrogen while for the other two oxazoline N atoms are trans to each other. This results in a significantly longer Yb—N(oxazoline) distance [2.468 (3) Å] for the bond trans to the anilide compared to those for the oxazoline N atoms trans to one another [2.376 (3), 2.390 (3) Å].
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32

Vanbiervliet, Elise, Stéphane Fouquay, Guillaume Michaud, Frédéric Simon, Jean-François Carpentier, and Sophie Guillaume. "α,ω-Epoxide, Oxetane, and Dithiocarbonate Telechelic Copolyolefins: Access by Ring-Opening Metathesis/Cross-Metathesis Polymerization (ROMP/CM) of Cycloolefins in the Presence of Functional Symmetric Chain-Transfer Agents." Polymers 10, no. 11 (November 9, 2018): 1241. http://dx.doi.org/10.3390/polym10111241.

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Epoxide- and oxetane-α,ω-telechelic (co)polyolefins have been successfully synthesized by the tandem ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclic olefins using Grubbs’ second-generation catalyst (G2) in the presence of a bifunctional symmetric alkene epoxide- or oxetane-functionalized chain-transfer agent (CTA). From cyclooctene (COE), trans,trans,cis-1,5,9-cyclododecatriene (CDT), norbornene (NB), and methyl 5-norbornene-2-carboxylate (NBCOOMe), with bis(oxiran-2-ylmethyl) maleate (CTA 1), bis(oxetane-2-ylmethyl) maleate (CTA 2), or bis(oxetane-2-ylmethyl) (E)-hex-3-enedioate (CTA 3), well-defined α,ω-di(epoxide or oxetane) telechelic PCOEs, P(COE-co-NB or -NBCOOMe)s, and P(NB-co-CDT)s were isolated under mild operating conditions (40 or 60 °C, 24 h). The oxetane CTA 3 and the epoxide CTA 1 were revealed to be significantly more efficient in the CM step than CTA 2, which apparently inhibits the reaction. Quantitative dithiocarbonatation (CS2/LiBr, 40 °C, THF) of an α,ω-di(epoxide) telechelic P(NB-co-CDT) afforded a convenient approach to the analogous α,ω-bis(dithiocarbonate) telechelic P(NB-co-CDT). The nature of the end-capping function of the epoxide/oxetane/dithiocarbonate telechelic P(NB-co-CDT)s did not impact their thermal signature, as measured by DSC. These copolymers also displayed a low viscosity liquid-like behavior and a shear thinning rheological behavior.
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33

Madadi, Nikhil R., Narsimha R. Penthala, Amit Ketkar, Robert L. Eoff, Vicenta Trujullo-Alonso, Monica L. Guzman, and Peter A. Crooks. "Synthesis and Evaluation of 2-Naphthaleno trans-Stilbenes and Cyanostilbenes as Anticancer Agents." Anti-Cancer Agents in Medicinal Chemistry 18, no. 4 (July 17, 2018): 556–64. http://dx.doi.org/10.2174/1871521409666170412115703.

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Background: Naphthalene is a good structural replacement for the isovanillin moiety (i.e. the 3- hydroxy-4-methoxyphenyl unit) in the combretastatin A-4 molecule, a natural product structurally related to resveratrol, which consistently led to the generation of highly cytotoxic naphthalene analogues when combined with a 3,4,5-trimethoxyphenyl or related aromatic system. Also, the naphthalene ring system is present in many current drug molecules that are utilized for anti-tumor, anti-arrhythmia and antioxidant therapy. Objective: In our continuing quest to improve the potencies of naturally occurring anti-cancer molecules through chemical modification, we have now synthesized a small library of 2-naphthaleno trans- stilbenes and cyanostilbenes that are structurally related to both resveratrol and DMU-212, and have evaluated these novel analogs against a panel of 54 human tumor cell lines. Method: A series of 2-naphthaleno-containing trans-stilbenes 3a-3h (Scheme 1) were synthesized by Wittig reaction of a variety of aromatic substituted benzyl-triphenylphosphonium bromide reactants with 2- naphthaldehyde using n-BuLi as a base in THF. A second series of 2-naphthaleno trans-cyanostilbenes analogs 5a-5h was synthesized by reaction of 2-naphthaldehyde (2; 1 mmol) with an appropriately substituted 2- phenylacrylonitrile 4a-4h; 1 mmol) in 5% sodium methoxide/methanol. The reaction mixture was stirred at room temperature for 2-3 hours and the reaction allowed to go to completion (TLC monitoring), during which time the desired product precipitated out of the solution as a solid. The resulting precipitate was filtered off, washed with water and dried to yield the desired compound in yields ranging from 70-95% (Scheme 2). Results: The percentage growth inhibition of 54 human cancer cell lines in a primary NCI screen after exposure to compounds 3a, 3d, 5b and 5c was carried out. The results showed that only compounds 5b and 5c met the criteria for subsequent testing to determine growth inhibition values (GI50) in dose-response studies. At 10-5 M concentration, compounds 5b and 5c exhibited cytotoxic activity against leukemia cell lines HL-60(TB) and SR, lung cancer cell line NCI-H522, colon cancer cell lines COLO 205 and HCT-116, CNS-cancer cell line SF-539, melanoma cell line MDA-MB-435, and breast cancer cell line BT-549. The naphthalene trans-stilbene analogue 3a, exhibited significant growth inhibition against only one cell line, melanoma cell line MDA-MB-435 (96 % growth inhibition). Compound 3d was inactive in the 10-5 M single dose screen. Conclusion: We have synthesized a small set of novel 2-naphthaleno stilbenes and cyanostilbenes and evaluated several of these compounds for their anticancer properties against a panel of 54 human tumor cell lines. The most active analogs, 5b and 5c, showed significantly improved growth inhibition against the human cancer cells in the NCI panel when compared to DMU-212. Of these compounds, analog 5c was found to be the most potent anticancer agent and exhibited significant growth inhibitory effects against COLO 205, CNS SF 539 and melanoma SK-MEL 5 and MDA-MB-435 cell lines with GI50 values ≤ 25 nM. Analog 5b also exhibited GI50 values in the range 25-41 nM against CNS SF 295 and melanoma MDA-MB-435 and UACC-62 cell lines. Compounds 5b and 5c were also cytotoxic towards the MV4-11 leukemia cell line with LD50 value of 450 nM and 200 nM, respectively, and demonstrated >50% inhibition of tubulin polymerization at concentrations below their LD50 values in these cells. In silico docking studies suggest that compounds 5b and 5c bind favorably at the colchicine- binding pocket of the tubulin dimer, indicating that both 5b and 5c may inhibit tubulin polymerization through a mechanism similar to that exhibited by colchicine. Derivative 5c demonstrated more favorable binding based on the docking score and buried surface area, as compared to compound 5b, in agreement with the higher observed potency of 5c against a broader range of tumor cell lines. Based on these results, analog 5c is considered to be a lead compound for further optimization as a clinical candidate for treating a variety of cancers.
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34

Hansen, Sonja, Kim Lewis, and Marin Vulić. "Role of Global Regulators and Nucleotide Metabolism in Antibiotic Tolerance in Escherichia coli." Antimicrobial Agents and Chemotherapy 52, no. 8 (June 2, 2008): 2718–26. http://dx.doi.org/10.1128/aac.00144-08.

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ABSTRACT Bacterial populations produce a small number of persister cells that exhibit multidrug tolerance. Persister cells are largely responsible for the antibiotic recalcitrance of biofilm infections. The mechanism of persister cell formation largely remains unknown due to the challenges in identifying persister genes. We screened an ordered comprehensive library of 3,985 Escherichia coli knockout strains to identify mutants with altered antibiotic tolerance. Stationary-state cultures in 96-well plates were exposed to ofloxacin at a concentration which allows only tolerant persister cells to survive. The persister cell level of each culture was determined. A total of 150 mutants with decreased persistence were identified in the initial screen, and subsequent validation confirmed that neither the growth rate nor the ofloxacin MIC was affected for 10 of them. The genes affected in these strains were dnaJ and dnaK (chaperones), apaH (diadenosine tetraphosphatase), surA (peptidyl-prolyl cis-trans isomerase), fis and hns (global regulators), hnr (response regulator of RpoS), dksA (transcriptional regulator of rRNA transcription), ygfA (5-formyl-tetrahydrofolate cyclo-ligase), and yigB (flavin mononucleotide [FMN] phosphatase). The prominent presence of global regulators among these strains pointed to the likely redundancy of persister cell formation mechanisms: the elimination of a regulator controlling several redundant persister genes would be expected to produce a phenotype. This observation is consistent with previous findings for a possible role of redundant genes such as toxin/antitoxin modules in persister cell formation. ygfA and yigB were of special interest. The mammalian homolog of YgfA (methenyltetrahydrofolate synthetase) catalyzes the conversion of 5-formyl-tetrahydrofolate (THF) into the rapidly degraded 5,10-methenyl-THF, depleting the folate pool. The YigB protein is a phosphatase of FMN which would deplete the pool of this cofactor. Stochastic overexpression of these genes could lead to dormancy and, hence, tolerance by depleting the folate and FMN pools, respectively. Consistent with this scenario, the overexpression of both genes produced increased tolerance to ofloxacin.
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35

Sarkheil, Marzieh, and Maryam Lashanizadegan. "Schiff base ligand derived from (±)trans-1,2-cyclohexanediamine and its Cu(II), Co(II), Zn(II) and Mn(II) complexes: Synthesis, characterization, styrene oxidation and hydrolysis study of the imine bond in Cu(II) Schiff base complex." Journal of the Serbian Chemical Society 81, no. 4 (2016): 369–82. http://dx.doi.org/10.2298/jsc150918006s.

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A Schiff base ligand (H2L) derived from 2?-hydroxypropiophenone and (?)trans-1,2-cyclohexanediamine was synthesized. The reactions of MCl2.xH2O (M =Cu(II), Co(II), Zn(II) and Mn(II))with the di-Schiff base ligand (H2L) were studied. This ligand when stirred with 1 equivalent of CuCl2.2H2O in the solution of ethanol and chloroform undergoes partial hydrolysis of the imino bond and the resultant tridentate ligand (HL?)immediately forms complex[CuL?Cl]?3/2CHCl3(1)with N2O coordination sphere. Under the same condition, the reaction of H2L with MCl2.xH2O (M = Co(II) (3), Zn(II) (4) and Mn(II) (5)) gave complexes[ML]?1/2CHCl3?3/2H2O (3-5)with N2O2 coordination sphere and no hydrolytic cleavage was occurred. Also, the reaction of H2L with CuCl2.2H2O in THF gave the complex CuL (2)with N2O2 coordination sphere. The ligand and complexes were characterized by FTIR, UV-Vis, 1H NMRand elemental analysis. The homogeneous catalytic activity of the complexes1, 3 and 5wasevaluated for the oxidation of styrene using tert-butyl hydroperoxide (TBHP) as oxidant. Finally, the copper(II) complex(1)encapsulated in the nanopores of zeolite-Y by flexible ligand method (CuL?-Y)and its encapsulation was ensured by different studies. The catalytic performance of heterogeneous catalyst in the styrene oxidation with TBHP was investigated. The catalytic tests showed that the homogenous and heterogeneous catalysts were active in the oxidation of styrene.
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36

Hollfelder, Christoph O., Melanie Meermann-Zimmermann, Georgios Spiridopoulos, Daniel Werner, Karl W. Törnroos, Cäcilia Maichle-Mössmer, and Reiner Anwander. "C–H-Bond Activation and Isoprene Polymerization Studies Applying Pentamethylcyclopentadienyl-Supported Rare-Earth-Metal Bis(Tetramethylaluminate) and Dimethyl Complexes." Molecules 24, no. 20 (October 15, 2019): 3703. http://dx.doi.org/10.3390/molecules24203703.

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As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (C5Me5 = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe2]3 are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe4)2] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C–H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)5(CH2)(Me)8] and metallocene dimers [Cp*2Ln(AlMe4)]2 (Ln = Tb, Gd). Applying TBME as a “cleaving” reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)2(Me)(CH2OtBu)2(AlMe4)]4 or monolanthanum complex [Cp*La(AlMe4){Me3Al(CH2)OtBu}] and monoyttrium complex [Cp*Y(AlMe4)(Me3AlOtBu)], respectively. Complexes [Cp*Ln(AlMe4)2] (Ln = Ho, Dy, Tb, Gd) and [Cp*LnMe2]3 (Ln = Ho, Dy) are applied in isoprene and 1,3-butadiene polymerization, upon activation with borates [Ph3C][B(C6F5)4] and [PhNHMe2][B(C6F5)4], as well as borane B(C6F5)3. The trans-directing effect of AlMe3 in the binary systems [Cp*Ln(AlMe4)2]/borate is revealed and further corroborated by the fabrication of high-cis-1,4 polybutadiene (97%) with “aluminum-free” [Cp*DyMe2]3/[Ph3C][B(C6F5)4]. The formation of multimetallic active species is supported by the polymerization activity of pre-isolated cluster [(Cp*Ho)3Me4(CH2)(thf)2].
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37

Marinier, Anne, Kurt Baettig, Carol Dallaire, Rita Pitteloud, and Pierre Deslongchamps. "Synthesis and transannular Diels–Alder reaction of a cis–trans–trans and a trans–cis–cis 13-membered macrocyclic trienone." Canadian Journal of Chemistry 67, no. 10 (October 1, 1989): 1609–17. http://dx.doi.org/10.1139/v89-246.

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The synthesis of the cis–trans–trans5 and trans–cis–cis6 macrocyclic trienones from cyclohexene is described. Upon heating at 300 °C, trienone 5 underwent 1,5-H shift and transannular Diels–Alder reaction to give adducts 33, 34, and 35 while trienone 6 provided tricyclic ketone 37. Keywords: transannular Diels–Alder reaction.
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38

Xiao, Jianliang, and Martin Cowie. ""A-frame" vs. "open-book" geometries in binuclear complexes bridged by diphosphines and mercaptothiazolinate ligands. Unusual examples involving a bridging bis(diphenylphosphino)ethane group." Canadian Journal of Chemistry 71, no. 5 (May 1, 1993): 726–37. http://dx.doi.org/10.1139/v93-096.

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Reaction of the tetracarbonyl species [M(CO)2(µ-mtz)]2 (M = Rh, Ir; mtz = 2-mercaptothiazolinate) with 1 equivalent of the diphosphines (Ph2P(CH2)nPPh2; n = 1 (dppm), 2 (dppe)) yields the compounds [M2(CO)2(µ-L)(µ-mtz)2] (M = Rh, L = dppm (1), dppe (3); M = Ir, L = dppm (2)), which readily undergo oxidative addition of iodine to give [M2I2(CO)2(µ-L)(µ-mtz)2] (M = Rh, L = dppm (4), dppe (6); M = Ir, L = dppm (5)). When 2 equivalents of dppm are used, the A-frame compounds [M2(CO)2(η1-mtz)(µ-mtz)(dppm)2] (M = Rh (7), Ir (8)) are afforded. In solution the dangling mtz group of 7 undergoes exchange with both the free mtz anion and the bridging mtz ligand. Compounds 7 and 8 are also produced by treatment of trans-[MCl(CO)(dppm)]2 (M = Rh, Ir) with 2 equivalents of the mtz anion. Reaction of these dppm-bridged dichloro species with 1 equivalent of the mtz anion yields [M2Cl(CO)2(µ-mtz)(dppm)2] (M = Rh (9a), Ir (10)). Compound 9a undergoes reversible Cl− dissociation to give [Rh2(CO)2(µ-mtz)(dppm)2][Cl] (9b), which is also the stable form in the solid. Reaction of 9 with CO gives the carbonyl-bridged species [Rh2(CO)2(µ-CO)(µ-mtz)(dppm)2][Cl]. The structures of 6 and 9b have been determined by X-ray crystallography. Compound 6 crystallizes in the triclinic space group [Formula: see text] with one-half equivalent of THF per asymmetric unit in a cell having a = 9.856(3) Å, b = 14.078(6) Å, c = 16.245(5) Å, α = 103.66(3)°, β = 93.21(3)°, γ = 92.91(3)°, V = 2182(1) Å3, and Z = 2, and has refined to R = 0.045 and Rw = 0.057 on the basis of 433 parameters varied. Compound 9b crystallizes with one equivalent of CH2Cl2 in the monoclinic space group P21/n with a = 11.400(1) Å, b = 21.944(2) Å, c = 22.134(1) Å, β = 92.494(7)°, V = 5532(1) Å3, and Z = 4, and has refined to R = 0.062 and Rw = 0.082 on the basis of 613 parameters varied.
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39

Schmid, S., and J. Strähle. "Zur Umsetzung von ReO2I(PPh3)2 mit PhNCO. Synthese und Kristallstrukturen von ReO2I(PPh3)2 · CHCl3, [ORe(OCONPh)I(PPh3)]3, Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) und Re(NPh)(NH2Ph)I2(PPh3) ( OReO3) / On the Reaction of ReO2I(PPh3)2 with PhNCO. Synthesis and Crystal Structures of ReO2I(PPh3)2 · CHCl3, [ORe(OCONPh)I(PPh3)]3, Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) and Re(NPh)(NH2Ph)I2(PPh3) ( OReO3)." Zeitschrift für Naturforschung B 46, no. 2 (February 1, 1991): 235–44. http://dx.doi.org/10.1515/znb-1991-0218.

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PhNCO reacts with oxo ligands at metal centers to form phenyl nitrene complexes. As an intermediate of this reaction we obtained with ReO2I(PPh3)2 (1) the trimeric complex [ORe(OCONPh)I(PPh3)]3 (2) in which the PhNCO moiety was added to an oxo ligand to form an N -phenyl carbamato group. This group acts as a bridging ligand chelating one Re atom via its N and one O atom and coordinating an other Re atom by its second O atom . 2 crystallizes as 2 · 2 CHCl3 in the triclinic space group P1̄ with a = 1423.1(5), b = 2443.3(7), c = 1403.8(6) pm , α = 92.31(3), β = 94.76(3), γ = 81.48(3)°, and Z = 2. From the mother liquor of 2 after a few days Re(NPh)(NH2Ph)I2(PPh3)(OCONHPh) (3) is formed as a partial hydrolysis product. 3 is monoclinic with the space group P21/n and a = 1163.0(4), b = 2527.0(3), c = 1243.9(5) pm, β = 98.04°, Z = 4. The Re atom exhibits an octahedral coordination w ith the two I atom s in a ?ra«s-arrangem ent and the phenyl nitrene ligand trans to the m onodentate PhN HCO2 group. The coordination is completed by a phosphine and an aniline ligand. Reaction of 2 with excess PPh3 yields 1. It crystallizes from CHCl3 as 1 · CHCl3 in the monoclinic space group P21/n with a = 975.9(3), b = 2731(1), c = 1417.3(6) pm , β = 93.35° and Z = 4. In 1 the Re atom is pentacoordinated in form of a trigonal bipyram id with the two phosphine ligands in axial positions. A solution of 2 in THF forms Re(NPh)(NH2Ph)I2(PPh3) (OReO3) (4) upon exposure to air at room temperature. 4 is obtained as orthorhombic crystals with the space group Pca21 and a = 1727(1), b = 1064.2(4), c = 1765.7(9) pm , Z = 4, and is an analogue of 3 from which it can be derived by substituting the carbamato ligand by a perrhenat ion. In 3 and 4 the phenyl nitrene ligand is bound by a Re = N triple bond of 172 pm in a linear arrangement Re = N - Ph .
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40

Serrano, Jose A., and Emilio Roman. "The configuration of trans-5-nitro-6-glyconorbornenes. Synthesis of the enantiomerically pure trans-5-nitronorbornene-6-carboxaldehydes." Journal of Organic Chemistry 54, no. 26 (December 1989): 6114–16. http://dx.doi.org/10.1021/jo00287a025.

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41

Vandenberghe, A. E. "mRNA 5'-leader trans-splicing in the chordates." Genes & Development 15, no. 3 (February 1, 2001): 294–303. http://dx.doi.org/10.1101/gad.865401.

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42

Wally, Verena, Alfred Klausegger, Ulrich Koller, Hanns Lochmüller, Sabine Krause, Gerhard Wiche, Lloyd G. Mitchell, Helmut Hintner, and Johann W. Bauer. "5′ Trans-Splicing Repair of the PLEC1 Gene." Journal of Investigative Dermatology 128, no. 3 (March 2008): 568–74. http://dx.doi.org/10.1038/sj.jid.5701152.

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43

King, David T., and Lucille W. Petruny. "The trans-Alabama superbolide of 5 December 1999." Eos, Transactions American Geophysical Union 84, no. 27 (July 8, 2003): 253–57. http://dx.doi.org/10.1029/2003eo270001.

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44

Hong, Zi-Ling, Jin-Cherng Huang, Soong-Yu Kuo, and Chung-Yi Chen. "Amides from the Stems of Cinnamomum burmannii." Natural Product Communications 6, no. 9 (September 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600922.

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A novel amide, cinnabutamine (1), along with five known amides, cinnaretamine (2), N-trans-caffeoyl-5-hydroxytyramine (3), N-trans-feruloyltyramine (4), N-trans-feruloyl-5-methoxytyramine (5) and N-cis-feruloyl-5-methoxytyramine (6), were isolated from the stems of Cinnamomum burmannii (Lauraceae). Their structures were characterized and identified by spectral analysis.
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45

Nikolaidis, Pantelis, Elias Villiger, Rodrigo Vancini, Thomas Rosemann, and Beat Knechtle. "The Effect of Sex and Performance Level on Pacing in Duathlon." Sports 6, no. 4 (November 23, 2018): 152. http://dx.doi.org/10.3390/sports6040152.

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The purpose of the present research was to study the effect of sex and performance on pacing in short (Run1-10 km, Bike-50 km and Run2-5 km) and long distance (Run1-10 km, Bike-150 km and Run2-30 km) in the Powerman World Championship ‘Powerman Zofingen’. All finishers (n = 6671; women, n = 1037; men, n = 5634) competing either in the short or long distance versions of ‘Powerman Zofingen’ from 2003 to 2017 were analyzed for the time spent in each discipline (Run1, Bike and Run2), and in transition (Tran) from Run1 to Bike (Tran1) and from Bike to Run2 (Tran2). Athletes were ranked in quartile (Q) groups (Q1, Q2, Q3 and Q4), with Q1 the fastest and Q4 the slowest. In short distance, in both sexes, a medium discipline/transition × quartile interaction on relative time was observed (p < 0.001, η2p = 0.103 and η2p = 0.119, respectively), where Q1 was relatively the fastest in Tran1, Tran2 and Run2, and the slowest in Bike (p < 0.001). In long distance, in both sexes, a large discipline/transition × quartile interaction on relative time was observed (p < 0.001, η2p = 0.208 and η2p = 0.180, respectively), where Q1 was relatively the fastest in Tran1, Tran2 and Run2, and the slowest in Bike (p < 0.001). In summary, a similar trend of variation of pacing by performance level was observed in both sexes and distances with the fastest duathletes being the fastest in Run2 and both transitions, and the slowest in Bike.
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46

Vaughn, Anthony E., Charles L. Barnes, and Paul B. Duval. "X-ray Crystal Structure of Trans-UO2(N(SiMe3)2)2(THF)2: One in a Series of Uranyl(VI) Complexes Supported by Bis(trimethylsilyl)amido Ligands." Journal of Chemical Crystallography 37, no. 11 (October 2, 2007): 779–82. http://dx.doi.org/10.1007/s10870-007-9250-5.

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47

Medvedev, Ivan, Manfred Winnewisser, Frank C. De Lucia, Eric Herbst, Enyi Yi, Lai Peng Leong, Ryan P. A. Bettens, et al. "The Millimeter‐ and Submillimeter‐Wave Spectrum of the trans‐trans Conformer of Diethyl Ether (C 2 H 5 OC 2 H 5 )." Astrophysical Journal Supplement Series 148, no. 2 (October 2003): 593–97. http://dx.doi.org/10.1086/377259.

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48

Belotti, Diana, Florian Kampert, Mareike C. Jahnke, and F. Ekkehardt Hahn. "Oxidative addition of a 8-bromotheobromine derivative to d 10 metals." Zeitschrift für Naturforschung B 76, no. 3-4 (March 4, 2021): 227–35. http://dx.doi.org/10.1515/znb-2021-0011.

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Abstract Reaction of 8-bromo-7-ethyl-3-methylxanthine 1 with zerovalent group 10 metal complexes gave via an oxidative addition of the C–Br bond the neutral complexes trans-[2] (M = Pd) and trans-[3] (M = Pt) bearing a theobromine-derived azolato ligand. While the oxidative addition to [Pd0(PPh3)4] gave exclusively trans-[2], the reaction with the more substitution-inert [Pt0(PPh3)4] yielded after 1 day the kinetic product cis-[3], which was converted under heating for a total of 3 days completely into the thermodynamically more stable complex trans-[3]. Treatment of trans-[2], trans-[3] or the mixture of cis-/trans-[3] with the proton source HBF4⋅Et2O led to complexes trans-[4]BF4, trans-[5]BF4 and a mixture of cis/trans-[5]BF4 with retention of the original ratio of cis to trans, respectively. The molecular structures of the azolato complexes trans-[2] and trans-[3] and of the theobromine derived pNHC complexes trans-[4]BF4 and trans-[5]BF4 have been determined by X-ray diffraction studies.
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49

Chang, Thomas KH, Wendy BK Lee, and Hin Hin Ko. "Trans-resveratrol modulates the catalytic activity and mRNA expression of the procarcinogen-activating human cytochrome P450 1B1." Canadian Journal of Physiology and Pharmacology 78, no. 11 (November 1, 2000): 874–81. http://dx.doi.org/10.1139/y00-067.

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The present study was performed to determine if trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) modulates the catalytic activity and gene expression of cytochrome P450 1B1 (CYP1B1). In vitro, trans-resveratrol decreased human recombinant CYP1B1-catalyzed 7-ethoxyresorufin O-dealkylation activity, with an IC50 value of 1.4 ± 0.2 µM (mean ± SEM). Enzyme kinetic analysis indicated that trans-resveratrol inhibited CYP1B1 enzyme activity by a mixed-type inhibition and the apparent Ki was 0.75 ± 0.06 µM. To determine if trans-resveratrol modulates constitutive CYP1B1 gene expression, cultured MCF-7 human breast carcinoma cells were treated with trans-resveratrol. As indicated by RT-PCR analysis, treatment of MCF-7 cells with 10 µM trans-resveratrol decreased relative CYP1B1 mRNA levels after 5 h, but not after 1.5 or 3 h, of exposure. trans-Resveratrol treatment at 5, 7.5, 10, or 20 µM for 5 h produced a concentration-dependent decrease in CYP1B1 mRNA levels. The extent of suppression was ~50% at 20 µM concentration. The suppressive effect was not a consequence of a toxic response to the compound as assessed by a cell proliferation assay. Overall, our novel finding that trans-resveratrol inhibits the catalytic activity and suppresses the constitutive gene expression of CYP1B1 leads to the possibility that this nutraceutical confers protection against toxicity and carcinogenicity induced by compounds that undergo CYP1B1-catalyzed bioactivation.Key words: cytochrome P450, CYP1B1, 7-ethoxyresorufin, nutraceutical, trans-resveratrol.
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50

Tserng, K. Y., and S. J. Jin. "Oxidation of cis-5-unsaturated fatty acids in intact rat liver mitochondria: the operation of reduction pathways." Biochemical Journal 308, no. 1 (May 15, 1995): 39–44. http://dx.doi.org/10.1042/bj3080039.

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The metabolism of cis-5 unsaturated fatty acids was studied in intact rat liver mitochondria to assess the operation of a reduction pathway. By using direct quantification of metabolites with a capillary-column gas chromatography, 3-hydroxydodecanoate was identified among other metabolites when cis-5-dodecenoate was metabolized in intact rat liver mitochondria. The formation of 3-hydroxydodecanoate supports the existence of a reduction pathway in the metabolism of cis-5-unsaturated fatty acids. This metabolite cannot be produced from the conventional isomerase-mediated pathway. However, the data also indicated the possible operation of the conventional isomerase-mediated pathway in intact rat liver mitochondria. The reduction pathway appears to account for at least 61% of the pathway for cis-5-dodecenoate. This reduction pathway was likely to proceed from the dehydrogenation to trans-2,cis-5-dodecadienoyl-CoA, which was isomerized to delta 3, delta 5-dodecadienoyl-CoA, then to trans-2,trans-4-dodecadienoate. The reduction was mediated by 2,4-dienoyl-CoA reductase by the conversion of trans-2,trans-4-dodecadienoyl-CoA into trans-3-dodecenoyl-CoA. However, direct reduction of the cis-5 double bond was also shown to be operating, although to a lesser extent.
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