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Journal articles on the topic 'Complexes of Pyridine'

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Published: 5 June 2025

Last updated: 15 July 2025

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Webber, Christopher K., Erica K. Richardson, Diane A. Dickie, and T. Brent Gunnoe. "Electrochemically Active Copper Complexes with Pyridine-Alkoxide Ligands." Inorganics 12, no. 8 (2024): 200. http://dx.doi.org/10.3390/inorganics12080200.

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Pyridine-alkoxide (pyalk) ligands that support transition metals have been studied for their use in electrocatalytic applications. Herein, we used the pyalk proligands diphenyl(pyridin-2-yl)methanol ([H]PhPyalk, L1), 1-(pyren-1-yl)-1-(pyridin-2-yl)ethan-1-ol ([H]PyrPyalk, L2), 1-(pyridine-2-yl)-1-(thiophen-2-yl)ethan-1-ol ([H]ThioPyalk, L3), and 1-(ferrocenyl)-1-(pyridin-2-yl)ethan-1-ol ([H]FePyalk, L4) to synthesize CuII complexes that vary in nuclearity and secondary coordination sphere. Also, the proligand 1-(ferrocenyl)-1-(5-methoxy-pyridin-2-yl)ethan-1-ol ([H]FeOMePyalk, L5) was synthesized with a methoxy substituted pyridine; however, the isolation of a CuII complex ligated by L5 was not possible. Under variable reaction conditions, the pyalk ligands reacted with CuII precursors and formed either mononuclear or dinuclear CuII complexes depending on the amount of ligand added. The resulting complexes were characterized by single crystal X-ray diffraction, elemental analysis, and cyclic voltammetry.

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Niu, Xiang-Long, Lin Wei, Jian-Cheng Liu, et al. "Syntheses and structures of three macrocyclic supramolecular complexes and one ZnII-containing coordination polymer generated from a semi-rigid multidentate N-containing ligand." Acta Crystallographica Section C Structural Chemistry 77, no. 1 (2021): 29–39. http://dx.doi.org/10.1107/s2053229620016083.

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Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine (L), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn2Cl4(C12H10N6)2]·2CH2Cl2, (I), the analogous chloroform monosolvate, [Zn2Cl4(C12H10N6)2]·CHCl3, (II), bis(μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn2I4(C12H10N6)2]·2CH2Cl2, (III), and catena-poly[[[diiodidozinc(II)]-μ-4-{2-[(pyridin-3-yl)methyl]-2H-tetrazol-5-yl}pyridine] chloroform monosolvate], {[ZnI2(C12H10N6)]·CHCl3} n , (IV), by solution reaction with ZnX 2 (X = Cl and I) in a CH2Cl2/CH3OH or CHCl3/CH3OH mixed solvent system at room temperature. Complex (I) is isomorphic with complex (III) and has a bimetallic ring possessing similar coordination environments for both of the ZnII cations. Although complex (II) also contains a bimetallic ring, the two ZnII cations have different coordination environments. Under the influence of the I− anion and guest CHCl3 molecule, complex (IV) displays a significantly different structure with respect to complexes (I)–(III). C—H...Cl and C—H...N hydrogen bonds, and π–π stacking or C—Cl...π interactions exist in complexes (I)–(IV), and these weak interactions play an important role in the three-dimensional structures of (I)–(IV) in the solid state. In addition, the fluorescence properties of L and complexes (I)–(IV) were investigated.

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Śliwa, Wanda, and Małgorzata Deska. "Platinum(II) Complexes of Pyridines. A Review." Collection of Czechoslovak Chemical Communications 64, no. 3 (1999): 435–58. http://dx.doi.org/10.1135/cccc19990435.

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The chemistry of platinum(II) complexes of pyridine and related compounds is reviewed. Also the oxidative addition reaction to platinum(II) complexes of pyridines, as a method of conversion of Pt(II) into Pt(IV) species is described. A review with 90 references.

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Nakanishi, Takumi, and Osamu Sato. "Crystal structures of two nickel compounds comprising neutral NiIIhydrazone complexes and dicarboxylic acids." Acta Crystallographica Section E Crystallographic Communications 73, no. 2 (2017): 103–6. http://dx.doi.org/10.1107/s2056989016020326.

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Two isostructural NiIIcompounds, bis{N-[1-(pyridin-2-yl-κN)ethylidene]pyridine-4-carbohydrazonato-κ2N′,O}nickel(II)–2,5-dichloroterephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Cl2O4), and bis{N-[1-(pyridin-2-yl-κN)ethylidene]pyridine-4-carbohydrazonato-κ2N′,O}nickel(II)–2,5-dibromoterephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Br2O4), were synthesized and their crystal structures determined. The pair ofN,N′,O-tridentateN-[1-(pyridin-2-yl-κN)ethyl]pyridine-4-carbohydrazonateLligands result in acis-NiO2N4octahedral coordination sphere for the metal ions. The asymmetric units consist of two half-molecules of the dicarboxylic acids, which are completed by crystallographic inversion symmetry. In the respective crystals, the 2,5-dichloroterephthalic acid (H2Cl2TPA,1-Cl) molecules form zigzag hydrogen-bonded chains with the [Ni(L)2] molecules, with the hydrogen-bond distances in1-Brslightly longer than those in1-Cl. The packing is consolidated by aromatic π–π stacking between the dicarboxylic acid molecules and terminal pyridine rings in [Ni(L)2] and short halogen–halogen interactions are also observed. The qualitative prediction of the H-atom position from the C—N—C angles of the terminal pyridine rings inLand the C—O distances in the carboxyl groups show that1-Cland1-Brare co-crystals rather than salts.

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Fatih, Mehmet EMEN, and Esra DEMİRDÖĞEN Ruken. "SYNTHESIS OF PYRIDINE DERIVATIVE POLYMERIC COPPER COMPLEX WITH METAL-AZID BONDS." Journal of Natural Science and Technologies 1, no. 1 (2022): 143–50. https://doi.org/10.5281/zenodo.7384181.

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In this study, pyridine-derived polymeric copper (II) complexes containing metal azide bonds were prepared. The characterization of the complexes given with the general formula, [Cu(L)2(N3)2Cl2]n (L1: 3,5-dimethyl pyridine, L2: 3,4-dimethyl pyridine, L3: 2-amino-3-methyl pyridine, L4: 2,6-diamino pyridine) was performed by FT-IR, AAS and magnetic susceptibility analyzes. The intense peak observed at 2045-2167 cm-1 in the spectra corresponds to the asymmetric azide vibrations, υas(N3-), which indicates that polymeric copper complexes are formed over azide bonds. Cu2+ amounts in the complexes were found in the range of 26.25%-33.61% from the AAS results. The thermal properties of polymeric copper complexes were investigated with the TG/DTA combined system. Unpaired electron numbers for copper complexes were found in the range of 0.89-1.45. Copper complexes are paramagnetic, and the number of unpaired electrons being different from the expected (n=1) value indicates that the geometry of the complex is distorted.

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Wang, Xu, Bradford R. Sohnlein, Shenggang Li, Jason F. Fuller, and Dong-Sheng Yang. "Pulsed-field ionization electron spectroscopy and molecular structures of copper-(pyridine)n (n = 1, 2) complexes." Canadian Journal of Chemistry 85, no. 10 (2007): 714–23. http://dx.doi.org/10.1139/v07-068.

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Cu-(pyridine)n (n = 1, 2) complexes are prepared in a pulsed laser ablation cluster source and identified using laser photoionization time-of-flight mass spectrometry. High-resolution electron spectra of these complexes are obtained using pulsed-field ionization zero electron kinetic energy (ZEKE) photoelectron spectroscopy. Metal-pyridine and pyridine-based vibrational modes are identified by comparing the ZEKE spectra with previous spectroscopic studies of isolated pyridine, pyridine adsorbed on metal surfaces, and other Cu complexes. Ground electronic states and molecular structures are determined by comparing the ZEKE spectra with ab initio and multidimensional Franck-Condon factor calculations. Metal-pyridine bond energies of the neutral complexes are derived from the measured ionization energies and thermochemical relations. The mono-ligand complex has C2v symmetry in both the neutral and ionized forms, whereas the di-ligand complex has an eclipsed pyridine configuration with D2h and C2 symmetries for the ion and neutral species, respectively. Although both the mono- and di-pyridine Cu complexes are formed by Cu binding to nitrogen atoms, important binding differences are found between these two complexes.Key words: pulsed-field ionization, ZEKE, photoelectron, ab initio, copper-pyridine complexes.[Traduit par la Rédaction]

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Nagaraju, N., J. Sreeramulu, V. Anjaneyulu, P. Malleswarareddy, and G. Ramamohan. "A study of in vitro antimicrobial activities and antioxidant of lanthanide complexes with a tri dentate Schiff base ligand." Research Journal of Chemistry and Environment 27, no. 5 (2023): 42–51. http://dx.doi.org/10.25303/2705rjce042051.

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The tridentate N3-type Schiff base 4-(anthracen-10-yl)-2,6-di(pyridin-2-yl)pyridine was synthesized from the condensation reaction of 2-acetyl pyridine and anthracene-10-carbaldehyde with ammonia using one pot methodology. This hybrid ligand was used for synthesis of lanthanide complexes (La, Sm and Eu) as novel potential biological agent. The lanthanide complexes were characterized on the basis of elemental, FT-IR, UV-Visible, mass spectrometry as well as molar conductivity. The complexes were screened for in vitro antibacterial and antifungal activities against the multidrug resistant pathogens such as Escherichia coli, Staphylococcus aureus and Aspergillus niger. The antimicrobial results revealed that Sm+3 complex has a good potency against different gram positive and gram negative bacteria in comparison with other complexes. All lanthanide complexes showed a moderate antioxidant activity with IC50. The DPPH· radical scavenging effects of the Schiff base ligand and its Ln (III) complexes were screened. The Ln (III) complexes were significantly more efficient in quenching DPPH· than the free Schiff base ligand.

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Liu, Ting, Yu-Peng Pan, Suna Wang, and Jian-Min Dou. "Two novel lead(II) complexes of 2-(hydroxymethyl)pyridine: a threefold diamondoid supramolecular network based on Pb4O4cores and a two-dimensional (4,4) network based on Pb2O2units." Acta Crystallographica Section C Crystal Structure Communications 69, no. 4 (2013): 394–99. http://dx.doi.org/10.1107/s0108270113006987.

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Reactions of 2-(hydroxymethyl)pyridine (Hhmp) with PbCl2and Pb(NO3)2at room temperature led to the formation of two novel compounds, namely tetrakis[μ3-(pyridin-2-yl)methanolato]-tetrahedro-tetrakis[chloridolead(II)], [Pb4(C6H6NO)4Cl4], (I), and poly[(μ2-nitrato)[μ2-(pyridin-2-yl)methanolato]lead(II)], [Pb(C6H6NO)(NO3)]n, (II). Compound (I) exhibits a tetranuclear Pb4O4cubane structure, which is connected through π–π stacking interactions between the pyridine groups of the (pyridin-2-yl)methanolate (hmp−) ligands and through C—H...Cl interactions to form an interesting threefold diamondoid network. Compound (II) possesses two-dimensional (4,4)-sql topology based on a Pb2O2unit, which is further extended into a three-dimensional supramolecular network through π–π stacking interactions between adjacent pyridine rings and through C—H...O interactions between the pyridine C atoms of the hmp−ligands and the nitrate anions.

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Kacsir, István, Adrienn Sipos, Evelin Major, et al. "Half-Sandwich Type Platinum-Group Metal Complexes of C-Glucosaminyl Azines: Synthesis and Antineoplastic and Antimicrobial Activities." Molecules 28, no. 7 (2023): 3058. http://dx.doi.org/10.3390/molecules28073058.

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While platinum-based compounds such as cisplatin form the backbone of chemotherapy, the use of these compounds is limited by resistance and toxicity, driving the development of novel complexes with cytostatic properties. In this study, we synthesized a set of half-sandwich complexes of platinum-group metal ions (Ru(II), Os(II), Ir(III) and Rh(III)) with an N,N-bidentate ligand comprising a C-glucosaminyl group and a heterocycle, such as pyridine, pyridazine, pyrimidine, pyrazine or quinoline. The sugar-containing ligands themselves are unknown compounds and were obtained by nucleophilic additions of lithiated heterocycles to O-perbenzylated 2-nitro-glucal. Reduction of the adducts and, where necessary, subsequent protecting group manipulations furnished the above C-glucosaminyl heterocycles in their O-perbenzylated, O-perbenzoylated and O-unprotected forms. The derived complexes were tested on A2780 ovarian cancer cells. Pyridine, pyrazine and pyridazine-containing complexes proved to be cytostatic and cytotoxic on A2780 cells, while pyrimidine and quinoline derivatives were inactive. The best complexes contained pyridine as the heterocycle. The metal ion with polyhapto arene/arenyl moiety also impacted on the biological activity of the complexes. Ruthenium complexes with p-cymene and iridium complexes with Cp* had the best performance in ovarian cancer cells, followed by osmium complexes with p-cymene and rhodium complexes with Cp*. Finally, the chemical nature of the protective groups on the hydroxyl groups of the carbohydrate moiety were also key determinants of bioactivity; in particular, O-benzyl groups were superior to O-benzoyl groups. The IC50 values of the complexes were in the low micromolar range, and, importantly, the complexes were less active against primary, untransformed human dermal fibroblasts; however, the anticipated therapeutic window is narrow. The bioactive complexes exerted cytostasis on a set of carcinomas such as cell models of glioblastoma, as well as breast and pancreatic cancers. Furthermore, the same complexes exhibited bacteriostatic properties against multiresistant Gram-positive Staphylococcus aureus and Enterococcus clinical isolates in the low micromolar range.

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Hatua, Kaushik, and Prasanta K. Nandi. "Third-order NLO property of beryllium-pyridyne complexes." Journal of Theoretical and Computational Chemistry 13, no. 01 (2014): 1350075. http://dx.doi.org/10.1142/s0219633613500752.

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Six pyridyne isomers and their complexes with beryllium have been considered for the theoretical study of the third-order polarizability. The NLO properties are calculated by employing the DFT functionals BLYP, B3LYP, BHHLYP, B3PW91, BP86 and B2PLYP for the 6-311++G(d,p) basis set. The C - Be bond length in the complexes varies within 1.644 Å–1.771 Å indicating covalent interactions between the metal and pyridynes. The present investigation reveals that the magnitude of second-hyperpolarizability of pyridynes strongly enhances upon complex formation with beryllium. The maximum hyperpolarizability has been predicted for the 2,5-diberyllium pyridine complex. The lowest value of hyperpolarizability is obtained for the 2,3- and 3,4-diberyllium pyridine complexes. The chosen DFT methods predict almost identical pattern of variation of NLO property. The variation of second-hyperpolarizability has been satisfactorily explained by the excitation energy and transition dipole moment associated with the most dominant excited state.

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Xun-Zhong, Zou, Feng An-Sheng, Zeng Fu-Ran, et al. "Synthesis, Crystal Structures, and Antimicrobial and Antitumor Studies of Two Zinc(II) Complexes with Pyridine Thiazole Derivatives." Bioinorganic Chemistry and Applications 2020 (September 15, 2020): 1–9. http://dx.doi.org/10.1155/2020/8852470.

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Two pyridine thiazole derivatives, namely, 4-(pyridin-2-yl)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)thiazole (L1) and 4-(pyridin-3-yl)-2-(2-(pyridin-4-ylmethylene)hydrazinyl)thiazole (L2), were afforded by a cyclization reaction between α-haloketone and thioamide, and their Zn(II) complexes were prepared by the reaction of ligands and corresponding metal salts, respectively, and characterized by X-ray diffraction and elemental analysis. Both crystals were obtained by ether diffusion and crystallized in a monoclinic system. The in vitro antimicrobial activity of the Zn(II) complexes and ligands was screened using the microplate reader method, and in vitro antitumor activities of the complexes were evaluated by MTT, with a view to developing new improved bioactive materials with novel properties. The biological activity studies of the compounds showed that the metal complexes were more active than the free ligands, and some compounds had absolute specificity for certain bacteria or cancer cell lines.

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Shubina, E. N., E. A. Flick, and I. Yu Zhukova. "Donor-acceptor interactions of iodine with pyridine bases in aqueous and organic media." BIO Web of Conferences 173 (2025): 03014. https://doi.org/10.1051/bioconf/202517303014.

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Spectrophotometric studies were carried out on the possibility of the formation of complexes between active forms of iodine and pyridine bases in solvents of different polarities - water (H2O) and dichloromethane (CH2Cl2). Analysis of electronic absorption spectra showed the appearance of different forms of iodine when dissolved in H2O (220 nm, 290 nm, 360 nm, 460 nm) and in CH2Cl2 (240 nm, 300 nm, 504 nm). To prove the possible interaction of various forms of iodine with pyridine bases, absorption spectra of pyridine, 2,6-lutidine, collidine and mixtures (iodine-pyridine base) in H2O and CH2Cl2 were obtained. It has been established that pyridine bases are capable of stabilizing iodine and iodonium ions in the form of donor-acceptor complexes. This is confirmed by intense and wide absorption bands in the spectral region of 250–300 nm (H2O) and 250–450 nm (CH2Cl2), which is associated with charge transfer and the formation of donor-acceptor type complexes, for example, [PyI2] and [PyI]+. The stability constants (K) of the complexes were determined in CH2Cl2. In accordance with the obtained spectral and calculated data, the iodine-pyridine complex is the most stable (K = 0.45 l/mol) compared to similar complexes containing pyridine bases with large steric effects. Among the complexes formed between the iodonium ion and pyridine bases, the most stable was the complex of the iodonium ion with collidine (K = 22 l/mol).

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Huang, Yanmin, Erbin Kong, Junyan Zhan, et al. "Synthesis and Cytotoxic Evaluation of Steroidal Copper (Cu (II)) Complexes." Bioinorganic Chemistry and Applications 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/4276919.

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Using estrone and pregnenolone as starting materials, some steroidal copper complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide or diazanyl pyridine and then complexation of steroidal thiosemicarbazones or steroidal diazanyl pyridines with Cu (II). The complexes were characterized by IR, NMR, and HRMS. The synthesized compounds were screened for their cytotoxicity against HeLa, Bel-7404, and 293T cell lines in vitro. The results show that all steroidal copper (II) complexes display obvious antiproliferative activity against the tested cancer cells. The IC50 values of complexes 5 and 12 against Bel-7404 (human liver carcinoma) are 5.0 and 7.0 μM.

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Baker, AT, P. Singh, and V. Vignevich. "Iron(II) and Nickel(II) Complexes of 2,6-Di(thiazol-2-yl)pyridine and Related Ligands." Australian Journal of Chemistry 44, no. 8 (1991): 1041. http://dx.doi.org/10.1071/ch9911041.

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2,6-Di(thiazol-2-yl]pyridine (1a), 2,6-di(4-methylthiazol-2-yl)pyridine (1b) and 2,6-di(2-imid-azolin-2-yl)pyridine (3) have been prepared by the reaction of pyridine-2,6-dicarbothioamide with bromoacetaldehyde diethyl acetal, bromoacetone and ethylenediamine, severally. Bis ( ligand ) iron(II) and nickel(II) complexes of all ligands have been prepared. The bis ( ligand ) iron(II) complexes of (1a) and (3) are low-spin whereas that of (1b) is high-spin at room temperature and undergoes a thermally induced spin transition. The field strengths of the ligands , determined from the spectra of their nickel(II) complexes, correlate well with the observed magnetic behaviour of their iron(II) complexes. The field strengths of (1a) and (1b) are found to be marginally less than those of the isomeric ligands 2,6-di(thiazol-4-yl)pyridine (2a) and 2,6-di(2-methylthiazol-4-yl)pyridine (2b).

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Demirdogen, Ruken Esra, Tuncay Yeşilkaynak, Tetyana Tishakova, and Fatih Mehmet Emen. "Antibacterial Cellulose Acetate Microfibers Containing Pyridine Derivative Complexes." Chemistry & Chemical Technology 15, no. 2 (2021): 217–25. http://dx.doi.org/10.23939/chcht15.02.217.

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Pyridine (L1) and 2,4-dimethylpyridine (L2) halide complexes of the type of [ML2X2] were prepared and characterized via FT-IR and 1H NMR. The CA microfibers containing complexes were electrospun and investigated via FT-IR. The morphologies of the microfibers were investigated via FE-SEM. Antibacterial activities of the complexes and the fibers were investigated.

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Kim, Jiyun, Hyungwoo Hahm, Ji Yeon Ryu, et al. "Pyridine-Chelated Imidazo[1,5-a]Pyridine N-Heterocyclic Carbene Nickel(II) Complexes for Acrylate Synthesis from Ethylene and CO2." Catalysts 10, no. 7 (2020): 758. http://dx.doi.org/10.3390/catal10070758.

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Nickel(II) dichloride complexes with a pyridine-chelated imidazo[1,5-a]pyridin-3-ylidene py-ImPy ligand were developed as novel catalyst precursors for acrylate synthesis reaction from ethylene and carbon dioxide (CO2), a highly promising sustainable process in terms of carbon capture and utilization (CCU). Two types of ImPy salts were prepared as new C,N-bidentate ligand precursors; py-ImPy salts (3, 4a–4e) having a pyridine group at C(5) on ImPy and a N-picolyl-ImPy salt (10) having a picolyl group at N atom on ImPy. Nickel(II) complexes such as py-ImPyNi(II)Cl2 (7, 8a–8e) and N-picolyl-ImPyNi(II)Cl2 (12) were synthesized via transmetalation protocol from silver(I) complexes, py-ImPyAgCl (5, 6a–6e) and N-picolyl-ImPyAgCl (11). X-ray diffraction analysis of nickel(II) complexes (7, 8b, 12) showed a monomeric distorted tetrahedral geometry and a six-membered chelate ring structure. py-ImPy ligands formed a more planar six-membered chelate with the nickel center than did N-picolyl-ImPy ligand. py-ImPyNi(II)Cl2 complexes (8a–8e) with tert-butyl substituents exhibited noticeable catalytic activity in acrylate synthesis from ethylene and CO2 (up to 108% acrylate). Interestingly, the use of additional additives including monodentate phosphines increased catalytic activity up to 845% acrylate (TON 8).

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Cubo, Leticia, Thalia Parro, Amancio Carnero, Luca Salassa, Ana Matesanz, and Adoracion Quiroga. "Synthesis, Reactivity Studies, and Cytotoxicity of Two trans-Iodidoplatinum(II) Complexes. Does Photoactivation Work?" Inorganics 6, no. 4 (2018): 127. http://dx.doi.org/10.3390/inorganics6040127.

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trans-Platinum complexes have been the landmark in unconventional drugs prompting the development of innovative structures that might exhibit chemical and biological profiles different to cisplatin. Iodido complexes signaled a new turning point in the platinum drug design field when their cytotoxicity was reevaluated and reported. In this new study, we have synthesized and evaluated diodidoplatinum complexes trans-[PtI2(amine)(pyridine)] bearing aliphatic amines (isopropylamine and methylamine) and pyridines in trans configuration. X-ray diffraction data support the structural characterization. Their cytotoxicity has been evaluated in tumor cell lines such as SAOS-2, A375, T-47D, and HCT116. Moreover, we report their solution behavior and reactivity with biological models. Ultraviolet-a (UVA) irradiation induces an increase in their reactivity towards model nucleobase 5′-GMP in early stages, and promotes the release of the pyridine ligand (spectator ligand) at longer reaction times. Density Functional calculations have been performed and the results are compared with our previous studies with other iodido derivatives.

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Velada, José L., Luis C. Cesteros, and I. Katime. "Infrared Study of the Interactions between Poly(Vinyl Pyridines) and Poly(Mono-n-Alkyl Itaconates)." Applied Spectroscopy 50, no. 7 (1996): 893–99. http://dx.doi.org/10.1366/0003702963905529.

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In this paper we have performed a spectroscopic study of the polymer–polymer complexes and polymer blends formed by mixing poly-acids [a series of poly(mono- n-alkyl itaconates)], and polybases [poly(2-vinyl pyridine) and poly(4-vinyl pyridine)]. The poly(mono- n-alkyl itaconates) are proton donors and the poly(vinyl pyridines) are good proton-acceptor polymers. Therefore, these pairs of polymers can interact via hydrogen bonding under given conditions. The obtained spectroscopic results point out the existence of hydrogen bonding in the studied systems. In addition to the qualitative hydrogen-bonding evidence observed in the hydroxyl and carbonyl stretching region, the curve-fitting analysis of the characteristic modes of the pyridine groups allows a quantitative study of the specific interactions to be performed.

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Ali, Korany A., Mokhles M. Abd-Elzaher, and Khaled Mahmoud. "Synthesis and Anticancer Properties of Silver(I) Complexes Containing 2,6-Bis(substituted)pyridine Derivatives." International Journal of Medicinal Chemistry 2013 (March 5, 2013): 1–7. http://dx.doi.org/10.1155/2013/256836.

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Several new 2,6-bis(substituted)pyridine ligands and 2,6-bis(substituted)pyridine Ag(I) nitrate complexes were synthesized and characterized spectroscopically. The newly synthesized ligands include pyridine-2,6-bis(3-oxopropanenitrile) (1), pyridine-2,6-bis(2-cyano-N-phenyl-3-oxopropanethioamide) (2), and pyridine-2,6-bis((E)-2-(2-phenylhydrazono)-3-oxopropanenitrile) (3). The newly synthesized ligands and silver(I) complexes were evaluated for their in vitro anticancer activity against four human cancer cell lines including hepatocellular carcinoma (HePG2), lung adenocarcinoma (A549), colon carcinoma (HT29), and breast adenocarcinoma (MCF7). Most of the newly synthesized silver(I) complexes exhibited better activity than the ligands, and the results have been compared with doxorubicin as a reference drug.

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Islam, Faridul, Jannat Al Foisal, Mahbubur Rahman, et al. "Antimicrobial Activity of Cu(II) and Fe(III) with Pyridine Complexes as Ligands Contrary to Clinical Strains of Bacteria and Fungi Species." Asian Journal of Chemistry 31, no. 10 (2019): 2323–26. http://dx.doi.org/10.14233/ajchem.2019.22096.

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In this study, green coloured Cu(II) and red coloured Fe(III) complexes of pyridine were prepared and the elemental characterization confirmed their composition. The pyridine complexes of Cu(II) and Fe(III) were found very interesting and attractive as potential candidates with antimicrobial activity. Along with this, melting point, molar conductivity measurement, magnetic moment determination, electronic and FTIR spectroscopy were also measured to characterize the prepared complexes. Pyridine acts as monodentate which resulted in formation of square planar and octahedral structure of Cu(II) and Fe(III) complexes, respectively with the nitrogen atom pyridine ring by coordination bond. For antimicrobial activity studies Alternaria alternata, Bacillus cerelus, Botrgodiplodia theobromal, Colletotrichums corcolei, Escherichia coli, Fusarium equiseti, Macrophomina phaseolina, Salmonell typhi and Shigella dysenteriae were used. The prepared complexes showed inhibition against mycelial growth. Although the complexes showed satisfactory inhibition against the tested bacteria and fungi species, both of the complexes were comparatively better against bacteria than fungi compared to ligand.

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Sweety, Rathi, Maji Ankur, Singh Ovender, and Ghosh Kaushik. "Mononuclear iron complexes derived from tridentate ligands : Synthesis, characterization, DFT calculations and DNA interaction studies." Journal of Indian Chemical Society Vol. 92, Dec 2015 (2015): 1913–24. https://doi.org/10.5281/zenodo.5600125.

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Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247 667, Uttarakhand, India E-mail : ghoshfcy@iitr.ernet.in Fax : 91-1332-273560 Mononuclear iron(II)/(III) complexes derived from tridentate 3N donor ligands 1-phenyl-1-(pyridine-2-ylmethyl)- 2–(pyridine-2-ylmethylene)hydrazine (H-N3L) and 1-phenyl-2-(1-(pyridin-2-yl)ethylidene)-1-(pyridin-2-ylmethyl)hydrazine (Me-N3L) have been synthesized. Complexes Fe(H-N3L)Cl3 (1), [Fe(H-N3L)2 ](ClO4 )2 (2), Fe(Me-N3L)Cl3 (3) and [Fe(MeN3L)2 ](ClO4 )2 (4) have been characterized using various spectroscopic techniques. Theoretical studies were also performed for the representative complex Fe(H-N3L)Cl3 (1) to evaluate the structural parameters. Electrochemical studies were investigated for the representative complexes. DNA interaction studies were investigated using UV-visible absorption spectral studies, ethidium bromide displacement assay and circular dichroism spectral studies. Nuclease activity was investigated by DNA gel electrophoresis.

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Rubino, Simona, Rosa Alduina, Patrizia Cancemi, et al. "Mononuclear Perfluoroalkyl-Heterocyclic Complexes of Pd(II): Synthesis, Structural Characterization and Antimicrobial Activity." Molecules 25, no. 19 (2020): 4487. http://dx.doi.org/10.3390/molecules25194487.

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Two mononuclear Pd(II) complexes [PdCl2(pfptp)] (1) and [PdCl2(pfhtp)] (2), with ligands 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), were synthesized and structurally characterized. The two complexes showed a bidentate coordination of the ligand occurring through N atom of pyridine ring and N4 atom of 1,2,4-triazole. Both complexes showed antimicrobial activity when tested against both Gram-negative and Gram-positive bacterial strains.

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Hakimi, Mohammad, Zahra Mardani, Keyvan Moeini, Fabian Mohr, Esther Schuh, and Hooshang Vahedi. "Synthesis, Crystallographic and Spectral Characterization of a Cadmium Chloride Complex Containing a Novel Imidazo[1,5-a]Pyridine Derivative." Zeitschrift für Naturforschung B 67, no. 5 (2012): 452–58. http://dx.doi.org/10.5560/znb.2012-0064.

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The reaction between 2-(2-amino-ethylamino)ethanol and pyridine-2-carbaldehyde in a 1 : 3 molar ratio gave 3-(pyridin-2-yl)-1-(pyridin-2-ylmethyl)imidazo[1,5-a]pyridine (PPIP) which was characterized by elemental analysis and spectroscopic methods. The study of CSD-deposited structures revealed that PPIP is a new derivative of imidazo[1,5-a]pyridine. The cadmium chloride complex of this ligand [Cd(PPIP)Cl2][Cd(PPIP)Cl2]ʹ·3H2O (1) was prepared and identified by elemental analysis, FT-IR, Raman and 1H NMR spectroscopy, and single-crystal X-ray diffraction. In the crystal structure of 1, there are two cadmium complexes with slightly different coordination bond lengths and angles. Also water molecules are incorporated in the crystal network. The geometry around the cadmium atom which is coordinated by two pyridine and one imine nitrogen atoms and two chloride ions is distorted square pyramidal. All bond lengths compare well with CSD averages of similar structures. The hydrogen bonds including O-H...Cl and O-H...O present in the crystal structure of 1 are also comparable to those in analogs.

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Okawara, Toru, Masaaki Abe, Shiho Ashigara, and Yoshio Hisaeda. "Molecular structures, redox properties, and photosubstitution of ruthenium(II) carbonyl complexes of porphycene." Journal of Porphyrins and Phthalocyanines 19, no. 01-03 (2015): 233–41. http://dx.doi.org/10.1142/s1088424614501120.

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Two ruthenium(II) carbonyl complexes of porphycene, (carbonyl)(pyridine)(2,7,12,17-tetra-n-propylporphycenato)ruthenium(II) (1) and (carbonyl)(pyridine)(2,3,6,7,12,13,16,17-octaethylpor-phycenato)ruthenium(II) (2), have been structurally characterized by single-crystal X-ray diffraction analysis. Cyclic voltammetry has revealed that the porphycene complexes undergo multiple oxidations and reductions in dichloromethane and the reduction potentials are highly positive compared to porphyrin analogs. UV-light irradiation (400 nm or shorter wavelength region) of a benzene solution of 1 and 2 containing external pyridine leads to dissociation of the carbonyl ligand from the ruthenium(II) centers to give the corresponding bis-pyridine complexes. The identical reaction has been also studied for a porphyrin derivative (carbonyl)(pyridine)(2,3,7,8,12,13,17,18-octaethylporphyriato)ruthenum(II) (3). The first-order kinetic analysis has revealed that the photosubstitution of all of the compounds occurs in the order of 10-3 s-1 at 298 K but proceeds faster for complexes of porphycene (1 and 2) than that of porphyrin (3).

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Cibulka, Radek, Ivana Císařová, Jan Ondráček, František Liška, and Jiří Ludvík. "Electrochemical Reductions of Ni2+, Cu2+ and Zn2+ Complexes of Azinyl Methyl Ketoximes on Mercury." Collection of Czechoslovak Chemical Communications 66, no. 1 (2001): 170–84. http://dx.doi.org/10.1135/cccc20010170.

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Electroreductions of Ni2+, Cu2+ and Zn2+ complexes of azinyl (pyridin-2-yl, pyridazin-3-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazinyl) methyl ketoximes on mercury electrode were studied using dc polarography. Three different types of complex behavior on the mercury electrode were observed: In the Ni2+ complexes, the hydroxyimino group of the ligand is reduced, whereas in the Cu2+ complexes, the reduction proceeds on the metal ion. With Zn2+ complex of methyl pyridin-2-yl ketoxime, only reduction waves of the uncoordinated ligand and metal were observed due to a rapid decomplexation pre-equilibrium. The structure of [Zn(methyl pyridin-2-yl ketoxime)2(NO3)2], isolated from water-ethanolic solution, was determined by X-ray diffraction. The distorted octahedral coordination sphere around the zinc atom, made up of two pyridine and two oxime nitrogen atoms and two nitrate oxygen atoms, was verified.

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Sharmila, A., P. Thamizhini, and K. Lakshmi Prabha. "SYNTHESIS, SPECTRAL AND BIOLOGICAL STUDIES ON TRANSITION METAL COMPLEXES OF (Z)-2-(METHYLTHIO)-N-(PYRIDIN-2- YLMETHYLENE)ANILINE." Rasayan Journal of Chemistry, Special (2021): 180–87. http://dx.doi.org/10.31788/rjc.2021.1456643.

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The new Schiff base ligand (Z)-2-(methylthio)-N-(pyridin-2-ylmethylene)aniline MPMA derived from pyridine-2- carboxaldehyde and 2- (methylthio) aniline and its Cu(II), Co(II) and Zn(II) metal complexes were prepared and characterized by spectral, magnetic and electrochemical studies. The spectral studies revealed that the ligand MPMA was tridentate and coordinated to the metal through azomethine nitrogen atom, pyridine nitrogen atom and sulphur atom from amine, forming octahedral geometry for Cu2+,Co2+ and tetrahedral geometry for Zn2+ ions. It was further supported by molar conductance measurement, which indicated that the above-mentioned complexes 1 and 2 were formed in 1:2 metal- ligand ratio and complex 3 was formed in 1:1 metal-ligand ratio. The electrochemical study explored that the metal ions undergo quasi reversible redox reactions by two electron transfer processes. The bioefficacy of the Schiff base and their metal complexes were studied in-vitro against the growth of microbes to assess their antimicrobial potential. The antioxidant activity of the ligand and the metal complexes have also been studied. The antidiabetic activity of the ligand and metal complexes were screened against α-amylase enzyme and αglucosidase enzyme and compared with standard drug acarbose.

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Lang, Johannes, Daniela V. Fries, and Gereon Niedner-Schatteburg. "Characterization of Trinuclear Oxo Bridged Cobalt Complexes in Isolation." Zeitschrift für Physikalische Chemie 232, no. 5-6 (2018): 649–69. http://dx.doi.org/10.1515/zpch-2017-1046.

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AbstractThis study elucidates molecular structures, fragmentation pathways and relative stabilities of isolated trinuclear oxo bridged cobalt complexes of the structural type [Co3O(OAc)6(Py)n]+(OAc=acetate, Py=pyridine, n=0, 1, 2, 3). We present infrared multiple photon dissociation (IR-MPD) spectra in combination with quantum chemical calculations. They indicate that the coordination of axial pyridine ligands to the [Co3O(OAc)6]+subunit disturbs the triangular geometry of the Co3O core. [Co3O(OAc)6]+exhibits a nearly equilateral triangular Co3O core geometry. The coordination of one or two pyridine ligands disturbs this arrangement resulting in isosceles triangular Co3O core geometries (in the cases of n=1 and 2). Coordination of three pyridine ligands (n=3) results in an equilateral triangular Co3O core geometry as in the case of n=0. Collision induced dissociation (CID) studies reveal that the complexes undergo a consecutive elimination of pyridine and acetate ligands with increasing excitation energy. Relative stabilities of the complexes decrease with the number of coordinated pyridine ligands. The presented results help to gain a fundamental insight into the molecular structure of trinuclear oxo bridged cobalt complexes void of any external effects such as crystal packing or solvation.

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Wu, Xiuli, Rufei Ye, Ai-Quan Jia, Qun Chen, and Qian-Feng Zhang. "Syntheses, Crystal Structures and Electrochemical Properties of Acetylacetonato-Ruthenium Complexes Containing Substituted Pyridine Ligands." Zeitschrift für Naturforschung B 68, no. 9 (2013): 993–99. http://dx.doi.org/10.5560/znb.2013-2344.

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Treatment of Ru(acac)3 with 2-cyano-pyridine and 3,5-dimethyl-pyridine in the presence of zinc dust as reducing agent in refluxing THF afforded the ruthenium(II) complexes cis-[RuII(acac)2(2- CN-py)2] (1) and cis-[RuII(acac)2(3,5-Me2-py)2] (2), respectively. Interaction of Ru(acac)3 with 3- Me-pyridine and 3,5-Me2-pyridine in the presence of Br2 in refluxing THF gave the ruthenium(III) complexes [RuIII(acac)Br2(3-Me-py)2] (3) and [RuIII(acac)Br2(3,5-Me2-py)2] (4), respectively. The four complexes have been spectroscopically and electrochemically characterized, and their crystal and molecular structures have been established by X-ray crystallography

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Hvastijová, M., J. Kohout, J. W. Buchler, H. W. Katzenmeier, J. Kožíšek, and C. Didierjean. "Crystallographic and Spectroscopic Evidence of O-Bonding in 3d-MetaI Dicyanomethanidonitrite Complexes." Zeitschrift für Naturforschung B 56, no. 1 (2001): 100–104. http://dx.doi.org/10.1515/znb-2001-0117.

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Abstract The coordination of the dicyanomethanidonitrite group through the nitroso oxygen atom in the tetrakis(pyridine) complexes [M{ONC(CN)2}2(py)4], M = Ni, Co, Cu, and in the bis(pyridine) complex [Cu{ONC(CN)2}2(py)2] was proved by X-ray crystallography of the Ni11 complex and re-evaluated infrared spectra. The Ni11 and Co11 complexes exhibit almost octahedral structures composed of four pyridine nitrogen atoms and two oxygen atoms of dicyanomethanidonitrite ions. Both copper(II) complexes display a considerable axial distortion of the pseudooctahedral arrangement. In the bis(pyridine) Cu11 complex the ONC(CN)2 groups are involved in the bridging function by use of the oxygen and nitrile nitrogen atoms.

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MaGee, Karen D. M., Guy Travers, Brian W. Skelton, Massimilliano Massi, Alan D. Payne, and David H. Brown. "Synthesis, Solid-state Structures, Solution Behaviour and Catalysis Studies of Nickel Complexes of Bis(benzimidazolin-2-ylidene)pyridine Pincer Ligands." Australian Journal of Chemistry 65, no. 7 (2012): 823. http://dx.doi.org/10.1071/ch12044.

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N-Heterocyclic carbene–nickel complexes with five- and four-coordinate geometries [(CNC)NiBr2] and [(CNC)NiBr]X (X = PF6 or BPh4) have been prepared with the pincer ligands 2,6-bis(N-octylbenzimidazolin-2-ylidene)pyridine and 2,6-bis(N-butyl-5,6-dimethoxybenzimidazolin-2-ylidene)pyridine. The addition of the n-octyl substituent significantly extends the solubility of the complexes and has allowed UV-vis solution studies of the complexes in dichloromethane and methanol. The four- and five-coordinate species exist in equilibrium in solution and this equilibrium has been explored by UV-vis studies. The complexes have also been characterized by NMR studies, and single crystal X-ray diffraction studies have been performed on [(CNC)NiBr2] (where CNC = 2,6-bis(N-octylbenzimidazolin-2-ylidene)pyridine) and [(CNC)NiBr]BPh4 (where CNC = 2,6-bis(N-butyl-5,6-dimethoxybenzimidazolin-2-ylidene)pyridine).

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von der Heiden, Daniel, Kari Rissanen, and Máté Erdélyi. "Asymmetric [N–I–N]+ halonium complexes in solution?" Chemical Communications 56, no. 92 (2020): 14431–34. http://dx.doi.org/10.1039/d0cc06706g.

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Assessment of the solution equilibria of [bis(pyridine)iodine(i)]+ complexes by ESI-MS and NMR reveals a statistical ligand distribution across the iodine(i) centres with a preference to form complexes with a more basic pyridine.

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Pazderski, Leszek, and Pavel A. Abramov. "Au(III) Cyclometallated Compounds with 2-Arylpyridines and Their Derivatives or Analogues: 34 Years (1989–2022) of NMR and Single Crystal X-ray Studies." Inorganics 11, no. 3 (2023): 100. http://dx.doi.org/10.3390/inorganics11030100.

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A review paper on Au(III) cyclometallated compounds with 2-arylpyridines (2-phenylpyridine, 2-benzylpyridine, 2-benzoylpyridine, 2-phenoxypyridine, 2-phenylsulfanylpyridine, 2-anilinopyridine, 2-(naphth-2-yl)pyridine, 2-(9,9-dialkylfluoren-2-yl)pyridines, 2-(dibenzofuran-4-yl)pyridine, and their derivatives) and their analogues (2-arylquinolines, 1- and 3-arylisoquinolines, 7,8-benzoquinoline), with 113 references. A total of 554 species, containing κ2-N(1),C(6′)*-Au(III), or analogous moiety (i.e., chelated by nitrogen of the pyridine-like ring and the deprotonated ortho- carbon of the phenyl-like ring) and, thus, possessing a character intermediate between metal complexes and organometallics, studied in the years 1989–2022 by NMR spectroscopy and/or single crystal X-ray diffraction (207 X-ray structures), are described. The compounds for which biological or catalytic activity and the luminescence properties were studied are also quoted.

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Stritt, Anika, E. Alper Ünal, Elisabeth Irran, and Andreas Grohmann. "“Coordination caps” of graded electron-donor capacity." Zeitschrift für Naturforschung B 79, no. 12 (2024): 705–22. https://doi.org/10.1515/znb-2024-0093.

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Abstract An efficient synthesis of the novel {6-[1,1-di(pyridin-2-yl)ethyl]pyridine-2-yl}2-methyl-1,3-propanediamine (2) is reported, as well as a reliable large-scale synthesis (of the order of 100 g) of previously known 2,2’-[1-(6-chloropyridin-2-yl)ethane-1,1-diyl]dipyridine (4); the latter is the starting material for the preparation of the former, as well as a multitude of other polypodal polyamine/polyimine ligands. Both materials, as well as the intermediates in their multi-step syntheses, have been fully characterised. Ligand 2, in conjunction with ligands 2,2’-(pyridine-2,6-diyl)bis(2-methylpropane-1,3-diamine) (1) and 2,6-bis(1,1-di(pyridin-2-yl)ethyl)pyridine (3), establishes a series of tetrapodal pentadentate N5 ligands L of like scaffold, and thus coordination geometry, but graded primary amine/imine donor atom ratios. The iron(II) complexes [Fe(L)NCCH3](OTf)2 (L = 1: A; L = 2: B; L = 3: C; OTf = triflate) have been prepared and fully characterised, including X-ray single-crystal structure analyses. The metal-centred one-electron oxidation/reduction potential (FeII/FeIII) depends sensitively on the electron donor capacity of the capping ligand used, as demonstrated by cyclic voltammetry. Whereas the acetonitrile ligand in A and C is readily exchanged for a methanol ligand in methanol solution, the resulting complexes showing variable-temperature spin crossover (SCO) in solution, B has been found to be inert to this type of ligand exchange.

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Tarafder, M. Tofazzal H., Wan M. Z. W. Yunus, and Sidik Silong. "Some Organoperoxo Complexes of Tin(IV)." Australian Journal of Chemistry 50, no. 3 (1997): 229. http://dx.doi.org/10.1071/c96141.

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Some novel organoperoxo complexes of tin were prepared by the oxidative addition of dioxygen with Sn 2+. These are the first reported examples of this kind. The complexes isolated have the compositions [Sn(O2)2.2L], [Sn(O2)2L′], [Sn(O2)L′′2], [Sn(O2)C5H3N(COO)2H2O] and [Sn(O2)2L′′′] (L = pyridine, pyridine N-oxide, triphenylphosphine oxide, aniline; L′ = ethylenediamine, 2-aminopyridine, o-phenylenediamine; L′′ = pyridine-2-carboxylato, 2-aminophenolato, quinolin-8-olato, glycinato; L′′′ = diethylenetriamine and triethylenetetramine). The complexes were characterized by elemental analysis, conductivity measurements and infrared spectroscopic studies. None of these complexes showed oxygen transfer reactions. The ν1(O-O) stretching frequencies appear at 805-820 cm-1 , and are significantly insensitive to the choice of the coligands used. Extensive pp-dp bonding in the complexes renders absolute kinetic stability to the complexes.

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Szafran, Miroslaw, and Zofia Dega-Szafran. "Complexes of Carboxylic Acids with Pyridines and Pyridine N-Oxides." HETEROCYCLES 37, no. 1 (1994): 627. http://dx.doi.org/10.3987/rev-93-sr5.

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Ariunbold, Gombojav O., Bryan Semon, Supriya Nagpal, and Prakash Adhikari. "Coherent Anti-Stokes–Stokes Raman Cross-Correlation Spectroscopy: Asymmetric Frequency Shifts in Hydrogen-Bonded Pyridine-Water Complexes." Applied Spectroscopy 73, no. 9 (2019): 1099–106. http://dx.doi.org/10.1177/0003702819857771.

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Hydrogen bonding is a vital molecular interaction for bio-molecular systems, yet deep understanding of its ways of creating various complexes requires extensive empirical testing. A hybrid femtosecond/picosecond coherent Raman spectroscopic technique is applied to study pyridine-water complexes. Both the coherent Stokes and anti-Stokes Raman spectra are recorded simultaneously as the concentration of water in pyridine varied. A 3 ps and 10 cm−1 narrowband probe pulse enables us to observe well-resolved Raman spectra. The hydrogen bonding between pyridine and water forms the complexes that have altered vibrational frequencies. These red and blue shifts were observed to be uneven. This asymmetry was result of the generated background nonlinear optical processes of pyridine-water complexes. This asymmetry tends to disappear as probe pulse further delayed attaining background-free coherent Raman spectra. For better visualization, spectral analyses both traditional two-dimensional correlation spectroscopy and recent second-order correlation functions defined in frequency domain are employed. Recognized as a label-free and background-free technique, the coherent Raman spectroscopy, complemented with a known high-resolution spectroscopic correlation analysis, has potential in studying the hydrogen-bonded pyridine-water complexes. These complexes are of great biological importance both due to the ubiquitous nature of hydrogen bonds and due to the close resemblance to chemical bases in macro-biomolecules.

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Dammann, Wiebke, Tabea Buban, Carl Schiller, and Peter Burger. "Dinuclear tethered pyridine, diimine complexes." Dalton Transactions 47, no. 35 (2018): 12105–17. http://dx.doi.org/10.1039/c8dt02347f.

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Steel, Peter J., and Christopher M. Fitchett. "Flexibility in the Self-Assembly of Silver Complexes: Coordination Polymers from Multi-Armed Pyridylmethyleneoxy Ligands." Australian Journal of Chemistry 66, no. 4 (2013): 443. http://dx.doi.org/10.1071/ch12464.

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The syntheses of new silver complexes of five isomeric bis(pyridylmethyleneoxy)benzenes, differing in the position of substitution on the benzene and pyridine rings, and three isomeric 1,3,5-tris(pyridylmethyleneoxy)benzenes, differing in the position of substitution on the pyridine ring, are described. The structures of six of these complexes were characterised using X-ray crystallography, showing the formation of coordination polymers for 3-pyridyl- and 4-pyridyl-armed ligands and discrete complexes for 2-pyridyl-armed ligands. The precise nature of the structure was further determined by the relative orientation of the pyridine rings in each case.

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Baker, AT, and HA Goodwin. "Iron(II) and Nickel(II) Complexes of 2,6-Di(Thiazol-4-Yl)Pyridine and Related Ligands: Magnetic, Spectral and Structural Studies." Australian Journal of Chemistry 39, no. 2 (1986): 209. http://dx.doi.org/10.1071/ch9860209.

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2,6-Di(thiazol-4-yl)pyridine (1a), 2,6-di(2-methylthiazol-4-yl)pyridine (1b) and 2,6-di(2-phenylthiazol-4-yl)pyridine (1c) have been prepared by Hantzsch syntheses from 2,6-di(ω- bromoacetyl )pyridine and the appropriate thioamide. Bis ( ligand ) iron(II) and nickel(II) complexes of (1a) and (1b) have been prepared but no metal complexes of (1c) were isolated. The bis ( ligand ) iron(II) complexes of (1a) are low-spin whereas those of (1b) undergo thermally induced spin-transitions, both in the solid state and solution. The field strengths of the ligands , determined from the spectra of their nickel(II) complexes, correlate well with the observed magnetic behaviour of their iron(II) complexes. The structure of [FeL2][ClO4]2.H2O, L = (1a), was determined by single-crystal X-ray diffractometry . The complex cation has the meridional configuration with the ligand functioning as an approximately planar tridentate. The structural parameters relating to the Fe-N6 coordination sphere are remarkably similar to those found for bis (2,2′:6′, 2′- terpyridine )iron(II) bis ( perchlorate ) monohydrate.

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Kumar, Sushil, Shweta Soam, Sulekh Chandra, and Hariom Kumar Kaushik. "AZAMACROCYCLIC Cr(III) COMPLEXES: SYNTHESIS AND SPECTROSCOPIC STUDIES." RASAYAN Journal of Chemistry, Special Issue (2022): 280–84. http://dx.doi.org/10.31788/rjc.2022.1558155.

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The new tetra dentate aza-macrocyclic ligands LA prepared by 2,6 –diamino pyridine and 3-methyl-2,4-pentadione, Ligand LB prepared by 2,6-diamino-pyridine and 3-ethyl-2,4-pentadione, Ligand LC was prepared with the reaction of 5-bromo-2,3-diamino-pyridine with. 3-methyl-2,4-pentadione and Ligand LD were prepared with the reaction of 5-bromo-2,3-diamino-pyridine with 3-ethyl-2,4-pentadione. Ethyl Alcohol was used in the preparation of ligands as a solvent. All the Ligands were characterized with the help of elemental and spectral studies. Cr(III) complexes were prepared with these newly synthesized ligands. All the newly synthesized Chromium complexes are known to bind with overall composition M(L)X3 [where {M Cr(III), X = Cl- , & NO3,}]. Cr(III) complexes are categorized by electronic spectral studies, Electron paramagnetic resonance spectroscopy, Infrared spectroscopy, mass spectroscopy, magnetic susceptibility measurements, and conductivity bridge measurements, and with the help of these studies Cr(III) complexes were allocated with octahedral geometry.

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Li, Jinghua, and Lushan Wang. "Elucidation of the Mechanism for the S - N-type Smiles Rearrangement on Pyridine Rings." Australian Journal of Chemistry 62, no. 2 (2009): 176. http://dx.doi.org/10.1071/ch08205.

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The Smiles rearrangement (SR) is an important strategy for synthesizing heterocyclic compounds. Many pyridine moiety-containing complexes are biologically active. Although the success has been archived in the development of the SR on the pyridine ring to obtain pyridine moiety-containing heterocyclic compounds, not much is known about the detailed SR mechanism. Here, we report a theoretical study on a typical S–N-type SR reaction involved in the synthesis of thiazinone-fused pyridines. We studied both the ipso-SR process and the direct nucleophilic substitution reactions on the ortho-positions to rationalize the experimentally observed ipso-SR product. The calculated results show the ipso-SR consists of two elementary steps, the intramolecular ipso-position substitution and subsequent ring closure, and the barrier for the rate-determining step is 65.98 kJ mol–1 and the overall reaction is exothermic by 116.94 kJ mol–1, confirming the reaction is kinetically feasible and thermodynamically favourable under mild experimental conditions (such as controlled microwave heating). The present results provide a clear picture for understanding the S–N-type SR on the pyridine ring to synthesize pyridine moiety-containing heterocycles.

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Baker, AT, DC Craig, G. Dong, and AD Rae. "Metal Complexes of 1,3-Bis(Pyridin-2-yl)pyrazole: Spectral, Magnetic and Structural Studies." Australian Journal of Chemistry 48, no. 6 (1995): 1071. http://dx.doi.org/10.1071/ch9951071.

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Bis(ligand)iron(II) and nickel(II) complexes of the asymmetric tridentate ligand 1,3-bis(pyridin-2-yl) pyrazole , L, have been prepared. The iron(II) complex, [FeL2] [PF6]2, is high-spin in the solid state over the temperature range 304-102 K, with a magnetic moment of 5.27 BM at room temperature. The crystal structure of bis (1,3-bis(pyridin-2-yl) pyrazole )iron(II) bis (hexafluorophosphate ) has been determined by single-crystal X-ray diffractometry. The compound crystallized as yellow prisms, with the structure being disordered in the tetragonal space group P421c with Z = 2. Crystal data a = b = 8.785(1) Ǻ, c = 19.804(6) Ǻ. The iron(II) centre is in an N6 environment, where the six donor nitrogen atoms are provided by the two tridentate heterocyclic ligands. The complex cation has an approximately octahedral structure exhibiting tetragonal compression. The observed Fe-N(pyridine) and Fe-N( pyrazole ) distances are 2.308(4) and 2.019(7) Ǻ respectively, with the Fe-N(pyridine) distance being the longest observed to date.

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Hossain, M. S., C. M. Zakaria, and M. K. Zahan. "Synthesis and Characterization with Antimicrobial Activity Studies on some Transition Metal Complexes of N, O Donor Novel Schiff Base Ligand." Journal of Scientific Research 9, no. 2 (2017): 209–18. http://dx.doi.org/10.3329/jsr.v9i2.29780.

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Metal complexes of Mn(II), Fe(II), Co(II) and Cd(II) ions with Schiff base ligand 4-{(pyridin-2-ylimino)methyl}phenol derived from condensation of 2-amino pyridine with 4-hydroxybenzaldehyde was prepared. The ligand and complexes were isolated from the reaction in the solid form and characterized by conductivity, magnetic moment, TLC, IR, UV-Visible, thermal analysis and some physical measurements. During complexation reaction with transition metal ions Schiff base act as a deprotonated tridentate ligand and IR spectra showed that N and O atoms are coordinated to the central metal atom. The observed values confirmed that the complexes have octahedral geometry. The Schiff base and its metal complexes have been found to have moderate to strong antibacterial activity.

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Yamajala, Rajesh B. R. D. "Synthesis and characterization of penta-coordinated 2- and 4-substituted pyridine N-oxide silicon complexes." Mapana Journal of Sciences 19, no. 2 (2020): 11–19. http://dx.doi.org/10.12723/mjs.53.2.

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Novel penta-coordinated 2- and 4-substituted pyridine N-oxide silicon complexes were synthesized by the reaction of various 2- and 4-substituted pyridine N-oxides with silicon pinacolate. These complexes were characterized by 29Si NMR, 1H NMR and 13C NMR spectroscopy. The objectives of the present work is the study of influence of substitution at either 4 or 2-position of the pyridine N-oxide on the effect of the profile of pentacoordination.

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Dias, H. V. Rasika, and Abhijit Pramanik. "Nickel(II) carbonyl, ammonia, and acetonitrile complexes supported by a pyridine dipyrrolide pincer ligand." Acta Crystallographica Section E Crystallographic Communications 76, no. 11 (2020): 1741–47. http://dx.doi.org/10.1107/s2056989020013341.

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The synthesis, isolation and crystal structures of nickel(II) carbonyl, acetonitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr2py]2−, namely, carbonyl[2,2′-(pyridine-2,6-diyl)bis(3,5-di-p-tolylpyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CO)], ammine[2,2′-(pyridine-2,6-diyl)bis(3,5-di-p-tolylpyrrolido-κN)]nickel(II), [Ni(C41H33N3)(NH3)], and (acetonitrile-κN)[2,2′-(pyridine-2,6-diyl)bis(3,5-di-p-tolylpyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CH3CN)], as well as the free ligand 2,6-bis(3,5-di-p-tolylpyrrol-2-yl)pyridine, C41H35N3 or [pyrr2py]H2 are reported. The nickel complexes are four-coordinate and adopt a square-planar geometry. The CO stretch of the nickel-bound carbon monoxide ligand of [pyrr2py]Ni(CO) has been observed at 2101 cm−1. The ammonia and acetonitrile complexes, [pyrr2py]Ni(NH3) and [pyrr2py]Ni(NCMe) feature all-nitrogen coordination spheres around nickel consisting of different N-donor ligand types.

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Kumar, Birendra, Rekha Rani, Dayanand Prasad, Praveen Kumar Singh, Amit Kumar, and Shivadhar Sharma. "Electronic Structure and Spectral Study of Some Five Coordinate Complexes of Copper (II)." Oriental Journal Of Chemistry 35, no. 4 (2019): 1463–68. http://dx.doi.org/10.13005/ojc/350430.

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1-phenylazo-2-nephthol has been synthesized and used for complexation with Cu(II) metal ion along with pyridine, α-picoline, β- picoline, γ-picoline and water as secondary ligands. On the basis of elemental analysis and molar conductivity complexes were formulated as CuL2X [Where L is the prime ligand i.e 1-phenyl-azo-2-nephthol and X is the secondary ligand i.e. pyridine, α-picoline, β-picoline, and H2O.] The magnetic moment of these complexes (1.80 - 1.83 BM) indicates that these complexes are magnetically dilute. The appearance of 3 bands in the electronic spectra of complexes rules out the trigonal bipyramidal (D3h) symmetry arround Cu(II) ion in these complexes rather the electronic spectra favours square pyramidal (C4V) symmetry of these five coordinate complexes. The highest value of 10Dq clearly indicates the greater coordinating ability of α-picoline than pyridine, β-picoline and γ-picoline.

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Ponikwar, Walter, and Wolfgang Beck. "Metallkomplexe mit biologisch wichtigen Liganden, CLI [1]. Metallorganische Komplexe mit R-3-(3-Pyridyl)alaninat." Zeitschrift für Naturforschung B 58, no. 4 (2003): 318–23. http://dx.doi.org/10.1515/znb-2003-0411.

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Reactions of chloro bridged complexes with R-3-(3-pyridyl)alanine afford the chelate complexes LnM[NH2CH(CO2)CH2C5H4NH+]Cl− (LnM = Ph3P(Cl)Pd, (tol3P)(Cl)Pd, (Ph-pyridyl)2Ir, Cp٭(Cl)Rh, Cp٭(Cl)Ir, (p-Cymol)(Cl)Ru) with protonated pyridine substituents. An analogous Cp٭Rh complex with 3-(2-pyridyl)alaninate was also obtained. Addition of base (NaOMe) to these complexes gives dimeric and trimeric complexes with coordination of the pyridine N atom.

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L., D. DAVE, MATHEW CHERIAN, and OOMMEN VARUGHESE. "Copper(II) Complexes of 3-N-Aryl Substitute Thioquinazolones." Journal of Indian Chemical Society Vol. 63, Mar 1986 (1986): 273–75. https://doi.org/10.5281/zenodo.6240380.

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University Department of Chemistry, Bhavnagar University, Bhavnagar-364 002 Manuscript received 18 March 1985, accepted 2 December 1985 CuII complexes and their pyridine adducts of 3-phenyl/p-tolyl/p-methoxyphenyl/p- ethoxyphenyl/p-chlorophenyl/p-bromophenyl-quinazoline-2-thione-4-one (HL) are prepared. Elemental analysis, magnetic and spectral data show that the copper complexes without pyridine have square-planar structure and the pyridine adducts have tetragonal structure.

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Naziruddin, Abbas Raja, Anzhela Galstyan, Adriana Iordache, Constantin G. Daniliuc, Cristian A. Strassert, and Luisa De Cola. "Bidentate NHC^pyrozolate ligands in luminescent platinum(ii) complexes." Dalton Transactions 44, no. 18 (2015): 8467–77. http://dx.doi.org/10.1039/c4dt03651d.

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Samantray, Sagarika, Sreenivasulu Bandi, and Dillip K. Chand. "Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism." Beilstein Journal of Organic Chemistry 15 (May 21, 2019): 1129–40. http://dx.doi.org/10.3762/bjoc.15.109.

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The complexation study of cis-protected and bare palladium(II) components with a new tridentate ligand, i.e., pyridine-3,5-diylbis(methylene) dinicotinate (L1) is the focus of this work. Complexation of cis-Pd(tmeda)(NO3)2 with L1 at a 1:1 or 3:2 ratio produced [Pd(tmeda)(L1)](NO3)2 (1a). The reaction mixture obtained at 3:2 ratio upon prolonged heating, produced a small amount of [Pd3(tmeda)3(L1)2](NO3)6 (2a). Complexation of Pd(NO3)2 with L1 at a 1:2 or 3:4 ratios afforded [Pd(L1)2](NO3)2 (3a) and [(NO3)2@Pd3(L1)4](NO3)4 (4a), respectively. The encapsulated NO3 – ions of 4a undergo anion exchange with halides (F–, Cl– and Br– but not with I–) to form [(X)2@Pd3(L1)4](NO3)4 5a–7a. The coordination behaviour of ligand L1 and some dynamic properties of these complexes are compared with a set of known complexes prepared using the regioisomeric ligand bis(pyridin-3-ylmethyl)pyridine-3,5-dicarboxylate (L2). Importantly, a ligand isomerism phenomenon is claimed by considering complexes prepared from L1 and L2.

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