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Journal articles on the topic 'Pyridine Isomer'

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Published: 5 June 2025

Last updated: 1 August 2025

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1

Pięta, Ewa, Edyta Proniewicz, Bogdan Boduszek, Tomasz K. Olszewski, Younkyoo Kim, and Leonard M. Proniewicz. "Exploring the Isomer Dependent SERS Spectra of (diphenylphosphoryl)(pyridin-2, -3, and -4-yl)methanol Adsorbed on Gold Nanocolloids." Journal of Spectroscopy 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/894749.

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The surface-enhanced Raman scattering (SERS) spectra of three aminophosphonate derivatives of pyridine: (diphenylphosphoryl)(pyridin-2-yl)methanol (α-Pyr), (diphenylphosphoryl)(pyridin-3-yl)methanol (β-Pyr), and (diphenylphosphoryl)(pyridin-4-yl)methanol (γ-Pyr) were measured after immobilization onto colloidal gold surface. Changes in the wavenumber, broadness, and enhancement between the corresponding Raman and SERS bands allowed to deduce orientation of theα-,β-, andγ-isomers (α-,β-, andγ-refer to the position of the substituent relative to the ring nitrogen atom) of aminophosphonate deriva

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2

Wallenhorst, Carolin, Kirill V. Axenov, Joseph S. M. Samec, Roland Fröhlich, and Gerhard Erker. "A Salt Metathesis Route To Ruthenium Carbene Complex Isomers With Pyridine Dicarboxamide-Derived Chelate Pincer Ligands." Zeitschrift für Naturforschung B 62, no. 6 (2007): 783–90. http://dx.doi.org/10.1515/znb-2007-0606.

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Reaction of the doubly deprotonated pyridine 2,6-dicarboxamido ligand (1) with (PCy3)2Cl2 Ru=CHPh (3a) in THF gave a mixture of (lig)(PCy3)Ru=CHPh isomers (4). The pentane soluble N,N,O-4 isomer was isolated by extraction and characterized by X-ray diffraction. The O,N, O-4 isomer was identified in the residue. Single crystals of the closely related complex (lig)(NHC) Ru=CHPh, O,N,O-5, were obtained from the reaction of 1 with (NHC)(PCy3)Cl2Ru=CHPh (3b) and used for the X-ray crystal structure analysis of the system

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3

Caterbow, Daniel, Daniela Künzel, Michael G. Mavros, Axel Groß, Katharina Landfester, and Ulrich Ziener. "Septipyridines as conformationally controlled substitutes for inaccessible bis(terpyridine)-derived oligopyridines in two-dimensional self-assembly." Beilstein Journal of Nanotechnology 2 (July 26, 2011): 405–15. http://dx.doi.org/10.3762/bjnano.2.46.

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The position of the peripheral nitrogen atoms in bis(terpyridine)-derived oligopyridines (BTPs) has a strong impact on their self-assembly behavior at the liquid/HOPG (highly oriented pyrolytic graphite) interface. The intermolecular hydrogen bonding interactions in these peripheral pyridine units show specific 2D structures for each BTP isomer. From nine possible constitutional isomers only four have been described in the literature. The synthesis and self-assembling behavior of an additional isomer is presented here, but the remaining four members of the series are synthetically inaccessible

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4

Singh, Jaswinder, Yuekui Wang, and Gerhard Raabe. "Quantum-Chemical ab initio Calculations on the Three Isomers of Diborabenzene (C4H4B2)." Zeitschrift für Naturforschung A 65, no. 1-2 (2010): 113–22. http://dx.doi.org/10.1515/zna-2010-1-213.

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AbstractQuantum-chemical ab initio calculations up to the ZPE+CCSD(T)/aug-cc-pVTZ//MP2/6- 311++G** level were performed on three possible structural isomers of diborabenzene (C4H4B2). All three molecules were found to be local minima on the C4H4B2 energy surface and to have closed shell singlet ground states. While the ground states of the 1,3- and 1,4-isomer are planar and of C2v and D2h symmetry, respectively, 1,2-diborabenzene is non-planar with a C2 axis passing through the center of the BB bond and the middle of the opposite carbon-carbon bond as the only symmetry element. The energetical

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5

Taylor, Wesley G., Tse Wai Hall, and Carl E. Schreck. "An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics." Canadian Journal of Chemistry 70, no. 1 (1992): 165–72. http://dx.doi.org/10.1139/v92-027.

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The 15 2,2-dimethyloxazolidines described here were found to exist in solution predominantly as a single rotational isomer, unlike N-acetyloxazolidine (1), N-acetyl-2-methyloxazolidine (2), N-acetyl-2-(n-octyl)oxazolidine (3), and other known 2-substituted N-acyloxazolidines. Using 13C NMR spectroscopy, activation energies for interconversion of the E (minor) and Z (major) rotational isomers of 1–3 were determined from coalescence temperature measurements in pyridine-d5. A sample of N-acetyl-2,2-dimethyloxazolidine (4) was isolated for comparison. The rotational isomer of 4 was found by two-di

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6

Pearson, Tyler J., Ryoma Shimazumi, Julia L. Driscoll, Balu D. Dherange, Dong-Il Park, and Mark D. Levin. "Aromatic nitrogen scanning by ipso -selective nitrene internalization." Science 381, no. 6665 (2023): 1474–79. http://dx.doi.org/10.1126/science.adj5331.

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Nitrogen scanning in aryl fragments is a valuable aspect of the drug discovery process, but current strategies require time-intensive, parallel, bottom-up synthesis of each pyridyl isomer because of a lack of direct carbon-to-nitrogen (C-to-N) replacement reactions. We report a site-directable aryl C-to-N replacement reaction allowing unified access to various pyridine isomers through a nitrene-internalization process. In a two-step, one-pot procedure, aryl azides are first photochemically converted to 3 H -azepines, which then undergo an oxidatively triggered C2-selective cheletropic carbon e

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7

Luo, Hongyan, and Chris Orvig. "Rhenium complexes of P,P,P′,P′-tetrakis(o-hydroxyphenyl)diphosphinoethane." Canadian Journal of Chemistry 74, no. 5 (1996): 722–29. http://dx.doi.org/10.1139/v96-078.

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Preparation of the hydrochloride salt of a new potentially hexadentate ligand precursor P,P,P′,P′-tetrakis(o-hydroxyphenyl)diphosphinoethane dihydrochloride (abbreviated H4P2O4•2HCl) is described. From H4P2O4•2HCl, neutral [Re2O2Cl2(PPh3)2(μ-P2O4)] and dianionic [Re2O2Br4(μ-P2O4)]2− dinuclear rhenium(V) complexes were synthesized. The complexes have been characterized by elemental analysis, infrared spectroscopy, mass spectrometry, and 1H/31P{1H} NMR spectra. 31P{1H} NMR revealed that only one isomer, presumably the anti, was present for [Re2O2Cl2(PPh3)2(μ-P2O4)], and that two isomers, both an

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8

Mocilac, Pavle, Katie Donnelly, and John F. Gallagher. "Structural systematics and conformational analyses of a 3 × 3 isomer grid of fluoro-N-(pyridyl)benzamides: physicochemical correlations, polymorphism and isomorphous relationships." Acta Crystallographica Section B Structural Science 68, no. 2 (2012): 189–203. http://dx.doi.org/10.1107/s0108768112006799.

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An isomer grid of nine fluoro-N-(pyridyl)benzamides (Fxx) (x = para-/meta-/ortho-) has been examined to correlate structural relationships between the experimental crystal structure and ab initio calculations, based on the effect of fluorine (Fx) and pyridine N-atom (x) substitution patterns on molecular conformation. Eight isomers form N—H...N hydrogen bonds, and only one (Fom) aggregates via intermolecular N—H...O=C interactions exclusively. The Fpm and Fom isomers both crystallize as two polymorphs with Fpm_O (N—H...O=C chains, P-syn ) and Fpm_N (N—H...N chains, P-anti ) both in P21/n (Z′ =

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9

Holý, Antonín, and Ivan Rosenberg. "Synthesis of isomeric and enantiomeric O-phosphonylmethyl derivatives of 9-(2,3-dihydroxypropyl)adenine." Collection of Czechoslovak Chemical Communications 52, no. 11 (1987): 2775–91. http://dx.doi.org/10.1135/cccc19872775.

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Reaction of 9-(S)-(2,3-dihydroxypropyl)adenine (I) with chloromethanephosphonyl chloride (VII) in pyridine or triethyl phosphate, or with chloromethyl(pyridinio)phosphonate (IX) in pyridine, afforded a mixture of 2'-(IV) and 3'-O-chloromethanephosphonate (V) which were separated on anion exchange resin or alkylsilica gel. Treatment of compounds IV and V with aqueous alkaline hydroxide, followed by deionization, gave 9-(S)-(2-hydroxy-3-phosphonylmethoxypropyl)adenine (VI) and 9-(S)-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (III) (HPMPA), respectively. The (R)- and (RS)-forms of III and VI we

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10

Pearson, Céline, and André L. Beauchamp. "1H NMR study of paramagnetic rhenium(III) monomers with nitrogen heterocycles. Crystal structures of ReCl3L2(PPh3) complexes (L = pyridine, 3-picoline, and 1-methylimidazole)." Canadian Journal of Chemistry 75, no. 2 (1997): 220–31. http://dx.doi.org/10.1139/v97-026.

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Rhenium(III) monomers of the type ReCl3Ln(PPh3)3−n, where n = 1,2, and 3, were prepared for simple nitrogen heterocyclic ligands L and characterized mainly by 1H NMR and IR spectroscopies. Most of the 1H NMR signals of these paramagnetic compounds were assigned by using methylated pyridines. A mer-cis octahedral geometry slightly distorted by triphenylphosphine was determined by X-ray diffraction for three ReCl3L2(PPh3) complexes: L = pyridine, triclinic, [Formula: see text], a = 11.379, b = 13.532, c = 18.160 Ǻ, α = 80.16°, β = 89.57, γ = 86.27°, Z = 4, R = 0.076; L = 3-picoline, triclinic, [

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11

MUCENIECE, D., A. ZANDERSONS, and V. LUSIS. "ChemInform Abstract: New Aminocyclohexadiene Isomer from Hantzsch Pyridine Synthesis." ChemInform 29, no. 11 (2010): no. http://dx.doi.org/10.1002/chin.199811112.

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12

Kolev, Ts M., and P. Bleckmann. "Vibrational Assignment of 2-Benzoyl Pyridine and its18O Labelled Isomer." Spectroscopy Letters 22, no. 9 (1989): 1215–27. http://dx.doi.org/10.1080/00387018908054018.

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13

Mårtensson, Anna K. F., and Per Lincoln. "Binding of Ru(terpyridine)(pyridine)dipyridophenazine to DNA studied with polarized spectroscopy and calorimetry." Dalton Transactions 44, no. 8 (2015): 3604–13. http://dx.doi.org/10.1039/c4dt02642j.

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Achiral Ru(tpy)(py)dppz<sup>2+</sup> intercalated into DNA has similar intermolecular interactions as opposite enantiomers of its structural isomer, the “light-switch” complex Ru(bpy)<sub>2</sub>dppz<sup>2+</sup>.

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14

Riedel, Sophie, Maik Gerwig, Daniela Gerlach, et al. "The Hexacoordinate Si Complex SiCl4(4-Azidopyridine)2—Crystallographic Characterization of Two Conformers and Probing the Influence of SiCl4-Complexation on a Click Reaction with Phenylacetylene." Inorganics 11, no. 12 (2023): 473. http://dx.doi.org/10.3390/inorganics11120473.

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4-Azidopyridine (1) and SiCl4 react with the formation of the hexacoordinate silicon complex SiCl4(4-azidopyridine)2 (2). Upon dissolving in warm chloroform, the complex dissociates into the constituents 1 and SiCl4 and forms back upon cooling. Depending on the cooling, two different crystalline modifications of 2 were obtained, which feature two different trans-conformers. Slow cooling to room temperature afforded conformer 2′, which features coplanar pyridine rings. Rapid cooling to −39 °C afforded crystals of conformer 2″, in which the planes of the pyridine ligands are nearly orthogonal to

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15

Brovko, Anastasiya O., Natalya V. Kuratieva, Denis P. Pishchur, and Gennadiy A. Kostin. "Heteroleptic Complexes of Ruthenium Nitrosyl with Pyridine and Bypiridine—Synthesis and Photoisomerization." Molecules 29, no. 17 (2024): 4039. http://dx.doi.org/10.3390/molecules29174039.

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The reaction of [RuNO(Py)2Cl2OH] with bipyridine in water–ethanol media results in trans-(NO, OH)-[RuNO(Py)(Bpy)ClOH]+ with an acceptable yield (60–70%) as hexafluorophosphate salt. Further treatment of the hydroxy-complex with concentrated HF quantitatively leads to trans-(NO, F)-[RuNO(Py)(Bpy)ClF]+. Despite the chirality of both coordination spheres, the hexafluorophosphate salts crystallized as racemates. A NO-linkage isomerism study of the obtained complexes was performed at 80 K with different excitation wavelengths (405, 450, 488 nm). The most favorable wavelengths for the MS1 isomer (Ru

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16

S, Priyanka. "Recent advances in Synthesis & Pharmacotherapeutic potential of Benzothiazoles." Der Pharma Chemica 14, no. 1 (2022): 2. https://doi.org/10.5281/zenodo.13353756.

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Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquinoline is used to make reference to isoquinoline derivatives. 1-Benzylisoquinoline is the structural backbone in naturally occurring alkaloids including papaverine. The isoquinoline ring in these natural compounds derives from the aromatic amino acid tyrosine.

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17

Olbrykh, Arina, Aleksei Titov, Alexander Smol’yakov, Oleg Filippov, and Elena S. Shubina. "Exploring the Interaction of Pyridine-Based Chalcones with Trinuclear Silver(I) Pyrazolate Complex." Inorganics 11, no. 4 (2023): 175. http://dx.doi.org/10.3390/inorganics11040175.

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The investigation of the interaction of cyclic trinuclear silver(I) pyrazolate [AgPz]3 (Pz = 3,5-bis(trifluoromethyl)pyrazolate) with pyridine-based chalcones (anthracen-9-yl and phenyl-substituted ones) has been performed by IR-, UV-vis, and NMR spectroscopies in the solution. The carbonyl group participates in coordination with metal ions in all complexes. However, the network of π-π/M-π non-covalent intermolecular interactions mainly influences complex formation. The spectral data suggest retaining the structures for all studied complexes in the solution and solid state. E-Z isomerization i

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18

Black, DS, GB Deacon, and GL Edwards. "Observations on the Mechanism of Halogen-Bridge Cleavage by Unidentate Ligands in Square Planar Palladium and Platinum Complexes." Australian Journal of Chemistry 47, no. 2 (1994): 217. http://dx.doi.org/10.1071/ch9940217.

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Cyclo-palladation and - platination of nitrogen donor ligands lead to insoluble μ- chloro dimers which give μ- bromo and μ- iodo dimers on metathesis with the appropriate lithium halide. Addition of pyridine or 2,6-dimethylpyridine to the cyclopalladated dimers gives monomeric complexes with the halogen trans to the metal-carbon bond, whereas addition of 2,6-dimethylpyridine to the cycloplatinated complexes gives the isomer with the halogen cis to the metal-carbon bond. The results are discussed in terms of the mechanism of the bridge cleavage reaction.

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19

Sharma, Namita, and Bhupendra Nath Misra. "Synthesis and characterization of mixed anhydrides of O-benzylbenzohydroximic acid." Collection of Czechoslovak Chemical Communications 54, no. 10 (1989): 2738–47. http://dx.doi.org/10.1135/cccc19892738.

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Mixed anhydrides of O-benzylbenzohydroximic acid have been prepared by acylation and sulfonylation of O-benzylbenzohydroxamic acid using a variety of acyl and sulfonyl halides in the presence of trimethylamine and pyridine in dioxane and benzene. Structure elucidation of the resulting products was performed by chemical and spectroscopic methods. All evidences indicate that the products have the mixed anhydride structure with (Z)-configuration. Corresponding (E)-isomer and the isomeric N-acylated or sulfonylated products, if formed, could not be isolated. Several mixed anhydrides showed antipar

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20

Castiñeiras, Alfonso, Antonio Frontera, Isabel García-Santos, Josefa M. González-Pérez, Juan Niclós-Gutiérrez, and Rocío Torres-Iglesias. "Multicomponent Solids of DL-2-Hydroxy-2-phenylacetic Acid and Pyridinecarboxamides." Crystals 12, no. 2 (2022): 142. http://dx.doi.org/10.3390/cryst12020142.

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We prepared cocrystals of DL-2-Hydroxy-2-phenylacetic acid (D, L-H2ma) with the pyridinecarboxamide isomers, picolinamide (pic) and isonicotinamide (inam). They were characterized by elemental analysis, single crystal and powder X-ray, IR spectroscopy and 1H and 13C NMR. The crystal and molecular structures of (pic)-(D-H2ma) (1), (nam)-(L-H2ma) (2) and (inam)-(L-H2ma) (3) were studied. The crystal packing is stabilized primarily by hydrogen bonding and in some cases through π-π stacking interactions. The analysis of crystal structures reveals the existence of the characteristic heterosynthons

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21

Yoshikiyo, Keisuke, Yoshihisa Matsui та Tatsuyuki Yamamoto. "Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin". Beilstein Journal of Organic Chemistry 11 (2 вересня 2015): 1530–40. http://dx.doi.org/10.3762/bjoc.11.168.

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The quantitative analysis of reaction products showed that the reaction of 6A,6D-di-O-trityl-α-cyclodextrin (CD), AD-isomer, with trityl chloride in pyridine at 55 °C gave 6A,6B,6E-tri-O-trityl-α-CD, the amount of which was only 25% of that of simultaneously formed 6A,6B,6D-tri-O-trityl-α-CD. This indicates that the bulky trityl groups of glucopyranose-A and -D (Glu-A and -D, respectively) in the AD-isomer mainly retard the additional tritylation of the C(6)-OH of the adjacent glucopyranoses in a counter-clockwise direction (Glu-F and -C, respectively). 1H NMR spectra of the AD-isomer showed t

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22

Sun, Zhi Yuan, Hui Li, and Shou Zhi Pu. "Synthesizes and Properties of a Novel Unsymmetrical Photochromic Diarylethene Material." Advanced Materials Research 788 (September 2013): 215–18. http://dx.doi.org/10.4028/www.scientific.net/amr.788.215.

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A new unsymmetrical photochromic diarylethene, 1-(2,4-dimethoxy-5-pyrimidinyl)- 2-(2-methyl-5-pyridine-3-thienyl) perfluoroncyclopentene (1a) was synthesized and its photochemical and fluorescent properties were inverstigated. The measurement results demonstrated that the compound had good photochromism in hexane solution upon irradiation with 297 nm UV light. And the cyclization process of the compound were determined to be the zeroth order reaction by UV-Vis spectra. Besides, the open-ring isomer of the diarylethene exhibited relatively stronger fluorescence at 406 nm when excited at 289 nm

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23

Jankowski, Christopher K., Gaëtan LeClair, Jacqueline MR Bélanger, Jocelyn RJ Paré, and Marie-Rose VanCalsteren. "Microwave-assisted Diels-Alder synthesis." Canadian Journal of Chemistry 79, no. 12 (2001): 1906–9. http://dx.doi.org/10.1139/v01-183.

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The synthesis of isoquinolinone carboxylates was performed using arecoline or its isomer N-methyl tetrahydro pyridine carboxylate with Danishefsky's diene via thermal or microwave assisted Diels-Alder reaction. The comparison of both condensation modes showed that the microwave method not only afforded higher yields of the adducts, but also lead to the formation of a new α,β-unsaturated pyridyl ketone. All structures were identified with the help of high resolution 2D NMR.Key words: Diels-Alder microwave assisted reaction, microwave synthesis, Michael, diene, isoquinoline carboxylate synthesis

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Esselman, Brian J., Samuel M. Kougias, Maria A. Zdanovskaia, R. Claude Woods, and Robert J. McMahon. "Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine." Journal of Physical Chemistry A 125, no. 25 (2021): 5601–14. http://dx.doi.org/10.1021/acs.jpca.1c03246.

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25

Timothée, Lathion, and Piguet Claude. "Deciphering the Influence of Meridional versus Facial Isomers in Spin Crossover Complexes." Chem. Eur. J. 24, no. 2018 (2018): 16873–88. https://doi.org/10.5281/zenodo.1495095.

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Chelate coordination of non-symmetrical didentate pyrazine-benzimidazole (L1) or pyridine-benzimidazole (L2) N-donor ligands around divalent iron in acetonitrile produces stable homoleptic triple-helical spin crossover [Fe(Lk)3]2+ complexes existing as mixtures of meridional (C1- symmetry) and facial (C3-symmetry) isomers in slow exchange on the NMR timescale. The speciation deviates from the expected statistical ratio mer/fac=3:1, a trend assigned to the thermodynamic trans-influence, combined with solvation effects. Consequently, the observed spin state FeII lowspin $FeII high-spin equilibri

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Unruh, Tobias, and Peter Vöhringer. "Thermal Isomerization of [Co(acac)2(N3)(py)] in Liquid Solution Studied by Time-Resolved Fourier-Transform Infrared Spectroscopy." Zeitschrift für Physikalische Chemie 234, no. 7-9 (2020): 1549–66. http://dx.doi.org/10.1515/zpch-2020-0006.

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AbstractThe thermally induced stereochemical interconversion between the trans and cis isomers of [Co(acac)2(N3)(py)] in liquid solution is investigated with time-resolved Fourier-transform infrared spectroscopy. The complex is synthesized stereo-selectively in its trans-form. Upon dissolution of the trans-form, the kinetic build-up of the cis-form is evidenced by the spectro-temporal evolution of the FTIR-spectrum. The individual isomer-specific component spectra are in good agreement with calculated spectra obtained from density functional theory. The rate constants of the forward and backwa

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Nemykin, Viktor. "Electronic Structure, Spectroscopy, and Redox Properties of Highly Soluble (μ-oxo)Bis[Tetra(tert-butyl)(phthalocyaninato)Iron(III)] Complex and Its Pyridine Adduct Under Anaerobic Conditions in Non-Coordinating Solvents". ECS Meeting Abstracts MA2023-01, № 15 (2023): 1391. http://dx.doi.org/10.1149/ma2023-01151391mtgabs.

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The solid-state Mössbauer spectra of a highly soluble (μ-oxo)bis[tetra(tert-butyl)(phthalocyaninato)iron(III)] complex 1 ((PctBuFe)2O) consist of two doublets that represent bent geometry μ-oxo(1) (1a, ΔEQ = 0.43 mm/s, T = 10K) and linear geometry μ-oxo(2) (1b) isomers (ΔEQ = 1.40 mm/s, T = 10K) with the ratio between two isomers depending on the purification method. Both isomers were found to be diamagnetic and transform entirely in 1a isomer in solution. The room- and low-temperature MCD spectra of 1a show one Faraday A- and one B-terms between 670 and 720 nm, which correlate with the 690 nm

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Santana, Adriana Lídia, Cristiano Giacomelli, Paula Nunes Oliveira, Alfredo Tibúrcio Nunes Pires, José Roberto Bertolino, and Almir Spinelli. "Isomer-dependent properties of poly(vinyl pyridine)-based films grown on copper surfaces." Journal of Polymer Science Part B: Polymer Physics 47, no. 2 (2009): 215–25. http://dx.doi.org/10.1002/polb.21636.

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Yang, Xiao, Hao-Long Zhou, Chun-Ting He, et al. "Flexibility of Metal-Organic Framework Tunable by Crystal Size at the Micrometer to Submillimeter Scale for Efficient Xylene Isomer Separation." Research 2019 (October 17, 2019): 1–9. http://dx.doi.org/10.34133/2019/9463719.

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Understanding, controlling, and utilizing the flexibility of adsorbents are of great importance and difficulty. Analogous with conventional solid materials, downsizing to the nanoscale is emerging as a possible strategy for controlling the flexibility of porous coordination polymers (or metal-organic frameworks). We report a unique flexibility controllable by crystal size at the micrometer to submillimeter scale. Template removal transforms [Cu2(pypz)2]·0.5p-xylene (MAF-36, Hpypz = 4-(1H-pyrazol-4-yl)pyridine) with one-dimensional channels to α-[Cu2(pypz)2] with discrete small cavities, and fu

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Jiang, Duo Hua, Gang Liu, Wei Jun Liu, and Cong Bin Fan. "Synthesis, Photochromism Properties of a Novel Hybrid Diarylethene Based on Hydroxyl Group." Advanced Materials Research 399-401 (November 2011): 1180–83. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1180.

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A novel unsymmetrical diarylethene derivative 1-[2-methyl-5-(4-pyridine)-3-thienyl]-2-[2-methyl-5-(4-hydroxylphenyl)-3-thienyl]hexafluorocyclopentene (1a) was successfully synthesized. The properties of the compound, including photochromic and fluorescence properties of the diarylethene were also investigated systematically. The results showed that absorption maxima of this compound were observed at 606 nm in methanol and at 612 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. In methanol solution, the open-ring isomer of the diarylethene 1 exhibited relatively f

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Hodgson, Michael C., Anthony K. Burrell, Peter D. W. Boyd, Penelope J. Brothers, and Clifton E. F. Rickard. "Synthesis, structure and properties of ferrocene functionalized porphyrins." Journal of Porphyrins and Phthalocyanines 06, no. 11 (2002): 737–47. http://dx.doi.org/10.1142/s1088424602000853.

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A series of free-base and metallated mixed ferrocenamido- and pivalamidophenylporphy-rins have been prepared from the α,α′,α″,α‴ isomer of 5,10,15,20-tetra(o-aminophenyl)porphyrin. The X-ray crystal structure of the iron(III) α,α′,α″,α‴-5,10,15,20-tetrakis(o-ferrocenamidophenyl)-porphyrin bromide has been determined and compared with related structures of cobalt(III) α,α′,α″,α‴-5,10,15,20-tetrakis(o-pivalamidophenyl)porphyrin bromide pyridine and the free base α,α′,α″,α‴-5,10,15,20-tetrakis(o-pivalamidophenyl)porphyrin. In both metalloporphyrins the coordinated axial bromides are contained in

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32

Kumar, Kuppusamy Senthil, Ivan Šalitroš, Eufemio Moreno-Pineda, and Mario Ruben. "Spacer type mediated tunable spin crossover (SCO) characteristics of pyrene decorated 2,6-bis(pyrazol-1-yl)pyridine (bpp) based Fe(ii) molecular spintronic modules." Dalton Transactions 46, no. 30 (2017): 9765–68. http://dx.doi.org/10.1039/c7dt02219k.

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33

Collins, DJ, GD Fallon, and CE Skene. "Selective O-Methyloxime Formation From 6-Methoxy-2-[(1'-methyl-2',5'-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one." Australian Journal of Chemistry 47, no. 4 (1994): 649. http://dx.doi.org/10.1071/ch9940649.

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Reaction of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (4a) with 1 or 2 moles of O- methylhydroxylamine hydrochloride in pyridine gave (1′SR,2RS)-6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (E)-2′-O-methyloxime (5a), or the corresponding 2′,5′-bis(O-methyloxime ) (6), respectively. A minor product from the formation of the bis (O- methyloxime ) (6) was the (Z) isomer (5b) of the mono(O- methyloxime ) (5a); the structure and stereochemistry of (5a) and (5b) were established by X-ray crystallography. Reduction

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34

Jarończyk, Małgorzata, Sławomir Ostrowski, and Jan Cz Dobrowolski. "On Integral INICS Aromaticity of Pyridodiazepine Constitutional Isomers and Tautomers." Molecules 28, no. 15 (2023): 5684. http://dx.doi.org/10.3390/molecules28155684.

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The structure, energetics, and aromaticity of c.a. 100 constitutional isomers and tautomers of pyrido[m,n]diazepines (m = 1, 2; n = 2, 3, 4, 5; m ≠ n) were studied at the B3LYP/cc-pVTZ level. The pyrido[1,3]diazepines appear the most, while pyrido[2,4]diazepines are the least stable (ca. 26 kcal/mol). In the pyrido[1,n]diazepine group (n = 2–5), the [1,5] isomers are higher in energy by ca. 4.5 kcal/mol and the [1,4] ones by ca. 7 kcal/mol, and the pyrido[1,2]diazepines are the least stable (ca. 20 kcal/mol). All the most stable pyrido[1,n]diazepines have N-atoms near the ring’s junction bond

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35

Shibata, Keisuke, Mikihiro Hayashi, and Yoshihito Inai. "Experimental and Theoretical Investigation of Intrinsic Pyridine Isomer Effects on Physical Property Tuning of Metallo Supramolecular Polymers Bearing Multiple Pyridine Ligands." ACS Applied Polymer Materials 2, no. 6 (2020): 2327–37. http://dx.doi.org/10.1021/acsapm.0c00284.

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36

Crociani, Bruno, Simonetta Antonaroli, Maurizio Paci, Francesca Di Bianca, and Luciano Canovese. "Isomer Distribution and Interconversion in Cationic Allylpalladium(II) Complexes with 2-(Iminomethyl)pyridine Ligands." Organometallics 16, no. 3 (1997): 384–91. http://dx.doi.org/10.1021/om9608420.

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37

Friary, Richard, Andrew T. McPhail, and Vera Seidl. "Novel Syntheses of Tricyclic, N-Aryl, Pyridine- and Pyrazine-Fused Pyrimidones." Collection of Czechoslovak Chemical Communications 58, no. 5 (1993): 1133–50. http://dx.doi.org/10.1135/cccc19931133.

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2-methylthio-2-imidazoline and 2-methylthio-1,4,5,6-tetrahydro-2-pyrimidine amidated 2-chloro-3-pyridine- and 2-chloro-3-pyrazinecarbonyl chlorides. The products reacted with aromatic amines forming a series of tricyclic, linearly fused N-aryl pyrimidones. Included among these pyrimidones were 10-aryl-2,3-dihydroimidazo[1,2-a]pyrido[2,3-d]pyrimidin-5(10H)-ones, 11-aryl-2,3,4,11-tetrahydropyrido-[2,3-d]pyrimido[1,2-a]pyrimidin-6(6H)-ones, 10-aryl-2,3-dihydroimidazo[1,2-a]pyrazino[2,3-d]pyrimidin-5(10H)-ones and 11-aryl-2,3,4,11-tetrahydropyrimido-[1,2-a]pyrazino[2,3-d]pyrimidin-6(6H)-ones. 4,5,

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38

Robertson, Mark J., Geoffrey A. Lawrance, Marcel Maeder, and Peter Turner. "Octahedral Complexes of a Mixed N,N,O-Donor Ligand N-trans-(2'-hydroxycyclohexyl)-2-aminomethylpyridine." Australian Journal of Chemistry 57, no. 5 (2004): 483. http://dx.doi.org/10.1071/ch03208.

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The unsymmetric mixed-donor Nam,Npy,O-ligand N-trans-(2'-hydroxycyclohexyl)-2-aminomethylpyridine (pyca, 1) was readily prepared by reaction of an epoxide (cyclohexene oxide) with (2-aminomethyl)pyridine. The ligand forms octahedral bis-tridentate complexes, exemplified with isolation of copper(II), nickel(II), zinc(II), and cobalt(III) compounds; in addition, a square-planar palladium(II) complex with the ligand behaving as bidentate was prepared. The bis-tridentate octahedral complexes may exist in six geometric isomeric forms, and molecular mechanics analysis was employed to predict the mos

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39

Deady, Leslie W., and Clare L. Smith. "Tetracycle Formation from the Reaction of Acetophenones with 1-Aminoanthraquinone, and Further Annulation of Pyridine and Diazepine Rings." Australian Journal of Chemistry 56, no. 12 (2003): 1219. http://dx.doi.org/10.1071/ch03136.

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Acetophenones (H, o-, m-, p-Cl, o-aza) react with aminoanthraquinone in pyridine containing solid sodium hydroxide to form 6-(arylcarbonyl)methyl-2-aryl-7H-naphtho[1,2,3-de]quinolin-7-ones (with the 4-(arylcarbonyl)methyl isomer as minor product). Preformed 7H-benzo[e]perimidin-7-one with acetophenone underwent the second part of this process, i.e. nucleophilic substitution to form 6-phenacyl-7H-benzo-[e]perimidin-7-one. Further reactions are described, including cyclization with ammonium acetate/acetic acid to 2,7-diphenyl-1,6-diazabenzo[e]pyrene and 7-phenyl-1,3,8-triazabenzo[e]pyrene, respe

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40

Shustov, Gennady V., Michael TH Liu, and K. N. Houk. "Facile formation of azines from reactions of singlet methylene and dimethylcarbene with precursor diazirines: theoretical explorations." Canadian Journal of Chemistry 77, no. 5-6 (1999): 540–49. http://dx.doi.org/10.1139/v99-012.

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The reactions of the singlet methylene (1a) and dimethylcarbene (1b), with their diazirine precursors, diazirine (2a), and dimethyldiazirine (2b), have been studied theoretically using ab initio and density functional theory. The reaction has no activation barriers for the parent system (1a + 2a) and proceeds via a reactive complex and a transition state with a small negative enthalpy of activation Δ Hnot =298 = -1.1 kcal mol-1, ΔSnot =298 = -34.4 cal mol-1 K-1, ΔG°298 = 9.2 kcal mol-1) for the dimethyl derivatives (1b + 2b). The formation of N-methylene diazirinium ylides (3a,b) is exothermic

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41

Ragon, Florence, Korcan Yaksi, Natasha F. Sciortino, et al. "Thermal Spin Crossover Behaviour of Two-Dimensional Hofmann-Type Coordination Polymers Incorporating Photoactive Ligands." Australian Journal of Chemistry 67, no. 11 (2014): 1563. http://dx.doi.org/10.1071/ch14188.

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Two spin crossover (SCO)-active 2D Hofmann-type framework materials, [Fe(3-PAP)2Pd(CN)4] (A) and [Fe(4-PAP)2Pd(CN)4] (B) containing the photoactive azo-benzene-type ligands 3-phenylazo-pyridine (3-PAP) and 4-phenylazo-pyridine (4-PAP) were prepared. These materials form non-porous Hofmann-type structures whereby 2D [FeIIPd(CN)4] grids are separated by 3- or 4-PAP ligands. The iron(ii) sites of both materials (A and B) undergo abrupt and hysteretic spin transitions with characteristic transition temperatures T1/2↓,↑: 178, 190 K (ΔT: 12 K) and T1/2↓,↑: 233, 250 K (ΔT: 17 K), respectively. Photo-

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42

Hui, Alice K., Chun-Hsing Chen, Adam M. Terwilliger, Richard L. Lord, and Kenneth G. Caulton. "A tale of hydrogen abstraction, initially detectedviaX-ray diffraction." Acta Crystallographica Section C Structural Chemistry 70, no. 3 (2014): 250–55. http://dx.doi.org/10.1107/s2053229614003234.

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Reaction of a bis-tetrazinyl pyridine pincer ligand, btzp, with a vanadium(III) reagent gives not a simple adduct but dichlorido{3-methyl-6-[6-(6-methyl-1,2,4,5-tetrazin-3-yl-κN2)pyridin-2-yl-κN]-1,4-dihydro-1,2,4,5-tetrazin-1-yl-κN1}oxidovanadium(IV) acetonitrile 2.5-solvate, [V(C11H10N9)Cl2O]·2.5CH3CN, a species which X-ray diffraction reveals to have one H atom added to one of the two tetrazinyl rings. This H atom was first revealed by a short intermolecular N...Cl contact in the unit cell and subsequently established, from difference maps, to be associated with a hydrogen bond. One chlorid

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43

Mikata, Yuji, Aya Tsuruta, Hinata Koike, Sunao Shoji, and Hideo Konno. "Cd2+-Selective Fluorescence Enhancement of Bisquinoline Derivatives with 2-Aminoethanol Skeleton." Molecules 29, no. 2 (2024): 369. http://dx.doi.org/10.3390/molecules29020369.

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The development of fluorescent Cd2+ sensors requires strict selectivity over Zn2+ because of the high availability of Zn2+ in the natural environment. In this paper, bisquinoline-based fluorescent sensors with a 2-aminoethanol backbone were investigated. The weak coordination ability of quinoline compared to well-studied pyridine is suitable for Cd2+ selectivity rather than Zn2+. In the presence of 3 equiv. of metal ions, TriMeO-N,O-BQMAE (N,O-bis(5,6,7-trimethoxy-2-quinolylmethyl)-2-methylaminoethanol (3)), as well as its N,N-isomer TriMeO-N,N-BQMAE (N,N-bis(5,6,7-trimethoxy-2-quinolylmethyl)

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44

Prüfert, Chris, Raphael David Urban, Tillmann Georg Fischer, et al. "In situ monitoring of photocatalyzed isomerization reactions on a microchip flow reactor by IR-MALDI ion mobility spectrometry." Analytical and Bioanalytical Chemistry 412, no. 28 (2020): 7899–911. http://dx.doi.org/10.1007/s00216-020-02923-y.

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Abstract The visible-light photocatalytic E/Z isomerization of olefins can be mediated by a wide spectrum of triplet sensitizers (photocatalysts). However, the search for the most efficient photocatalysts through screenings in photo batch reactors is material and time consuming. Capillary and microchip flow reactors can accelerate this screening process. Combined with a fast analytical technique for isomer differentiation, these reactors can enable high-throughput analyses. Ion mobility (IM) spectrometry is a cost-effective technique that allows simple isomer separation and detection on the mi

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45

Corinti, Davide, Roberto Paciotti, Nazzareno Re, et al. "Binding motifs of cisplatin interaction with simple biomolecules and aminoacid targets probed by IR ion spectroscopy." Pure and Applied Chemistry 92, no. 1 (2020): 3–13. http://dx.doi.org/10.1515/pac-2019-0110.

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AbstractThe primary intermediates resulting from the interaction of cisplatin, cis-(PtCl2(NH3)2], most widespread antitumor drug, with biomolecular targets are characterized. Electrospray ionization is used to deliver ions formed in solution into the gas phase where they are structurally interrogated by vibrational “action” spectroscopy in conjunction with quantum chemical calculations. The aquation products, cis-[PtX(NH3)2(H2O)]+ (X = Cl, OH), lying along the path responsible for biological activity, are shown to display distinctive features responding to ligation pattern and optimized geomet

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46

Woodward, Madeleine S., Rhys P. King, Robert D. Bannister, et al. "Fluoro-Germanium (IV) Cations with Neutral Co-Ligands—Synthesis, Properties and Comparison with Neutral GeF4 Adducts." Inorganics 10, no. 8 (2022): 107. http://dx.doi.org/10.3390/inorganics10080107.

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The reaction of [GeF4L2], L = dmso (Me2SO), dmf (Me2NCHO), py (pyridine), pyNO (pyridine-N-oxide), OPPh3, OPMe3, with Me3SiO3SCF3 (TMSOTf) and monodentate ligands, L, in a 1:1:1 molar ratio in anhydrous CH2Cl2 formed the monocations [GeF3L3][OTf]. These rare trifluoro-germanium (IV) cations were characterised by microanalysis, IR, 1H, 19F{1H} and, where appropriate, 31P{1H} NMR spectroscopy. The 19F{1H} NMR data show that in CH3NO2 solution the complexes exist as a mixture of mer and fac isomers, with the mer isomer invariably having the higher abundance. The X-ray structure of mer-[GeF3(OPPh3

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Huang, Peng, Manju, Samrana Kazim, Luis Lezama, Rajneesh Misra, and Shahzada Ahmad. "Leverage of Pyridine Isomer on Phenothiazine Core: Organic Semiconductors as Selective Layers in Perovskite Solar Cells." ACS Applied Materials & Interfaces 14, no. 4 (2022): 5729–39. http://dx.doi.org/10.1021/acsami.1c21996.

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48

McCracken, R. O., and K. B. Lipkowitz. "Experimental and theoretical studies of anthelmintics: Oxfendazole and its imidazo[1,2-a]pyridine-2-carbamate isomer." International Journal for Parasitology 19, no. 4 (1989): 363–68. http://dx.doi.org/10.1016/0020-7519(89)90091-x.

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49

Dorman, P. Matisha, Brian J. Esselman, P. Bryan Changala, et al. "Rotational spectrum of anti- and gauche-4-cyano-1-butyne (C5H5N) – An open-chain isomer of pyridine." Journal of Molecular Spectroscopy 385 (March 2022): 111604. http://dx.doi.org/10.1016/j.jms.2022.111604.

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50

Dolnikowski, G. G., M. L. Gross, and E. L. Cavalieri. "Isomer differentiation in 7, 12-dimethylbenz[a]anthracene-pyridine adducts by fast atom bombardment tandem mass spectrometry." Journal of the American Society for Mass Spectrometry 2, no. 3 (1991): 256–58. http://dx.doi.org/10.1016/1044-0305(91)80053-a.

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