Synthesis and characterization of 2,2'-(pyridine-2,6-diyl)bis(1H-benzo[d]imidazol-3-ium) 2,4,6-trimethylbenzenesulfonate chloride by experimental and theoretical methods.

The title molecular salt (2), 2,2'-(pyridine-2,6-diyl)bis(1H-benzo[d]imidazol-3-ium) 2,4,6-trimethylbenzenesulfonate chloride (C19H15N5(2+)·C9H11O3S(-)·Cl(-)), was synthesized unexpectedly from the reaction of 2,6-bis(benzimidazol-2-yl)pyridine (1) with 2-mesitylenesulfonyl chloride. Spectroscopic techniques (FT-IR, NMR and UV-vis.) were used to characterize compounds 1 and 2. Solid-state structure of compound 2 was identified by X-ray crystallography. Theoretical characterization of the spectroscopic properties of compounds 1 and 2 was achieved using the density functional theory (DFT) method with the 6-311G(d,p) basis set, and the results were checked against the experimental data. Electronic absorption spectra of the compounds have also been obtained.

Synthesis and characterization of SiO2-supported ruthenium complexes containing aromatic sulfonamides: as catalysts for transfer hydrogenation of acetophenone.

3-Amino-N-aryl-benzenesulfonamides (1­3) were successfully synthesized by the reaction of m-phenylenediamine and various benzenesulfonyl chlorides. Then, a series of ruthenium complexes (4­6) were prepared from the reaction of [RuCl2(p-cymene)]2 and 1­3. Finally, SiO2-supported Ru(II) complexes (7­9) were prepared by an impregnation method. The synthesized compounds and materials were characterized by different methods such as NMR, FT-IR, TG/DTA, nitrogen adsorption­desorption (BET), SEM and EDX. Also, the solid state structures of 4­6 were determined by single-crystal X-ray diffraction. 4­9 were used as catalysts for the transfer hydrogenation of acetophenone. 4­9 showed good catalytic activity and so the effects of the different groups were also examined. For the transfer hydrogenation of acetophenone, 7­9 had similar activity to 4­6. However, the longer lifetime of 7­9 makes them more advantageous than the non-supported catalysts (4­6) in terms of catalytic cycle. Therefore, the effect of SiO2 was investigated as a catalyst and the results show that excess silicon(IV) oxide was a surprisingly active catalyst for the hydrogenation of acetophenone under these conditions.

Synthesis, spectroscopic characterization, X-ray structure and DFT studies on 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine.

The title molecule, 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine (C(33)H(25)N(5)), was synthesized and characterized by elemental analysis, FT-IR spectroscopy, one- and two-dimensional NMR spectroscopies, and single-crystal X-ray diffraction. In addition, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of the title compound in the ground state have been calculated using the density functional theory at the B3LYP/6-311G(d,p) level, and compared with the experimental data. The complete assignments of all vibrational modes were performed by potential energy distributions using VEDA 4 program. The geometrical parameters of the optimized structure are in good agreement with the X-ray crystallographic data, and the theoretical vibrational frequencies and GIAO (1)H and (13)C NMR chemical shifts show good agreement with experimental values. Besides, molecular electrostatic potential (MEP) distribution, frontier molecular orbitals (FMO) and non-linear optical properties of the title compound were investigated by theoretical calculations at the B3LYP/6-311G(d,p) level. The linear polarizabilities and first hyper polarizabilities of the molecule indicate that the compound is a good candidate of nonlinear optical materials. The thermodynamic properties of the compound at different temperatures were calculated, revealing the correlations between standard heat capacity, standard entropy, standard enthalpy changes and temperatures.

Concomitant polymorphism of a pyridine-2,6-dicarboxamide derivative in a single space group: experimental and molecular modeling study.

The title compound, N(2),N(6)-bis{2-[(Z)-2-hydroxybenzylideneamino]phenyl}pyridine-2,6-dicarboxamide (3), has been synthesized by the reaction of 2-{(2-aminophenylimino)methyl}phenol (1) with pyridine-2,6-dicarbonyl dichloride (2), and characterized by elemental analysis, FT-IR and NMR spectroscopies and thermal analysis. Compounds 1 and 3 were evaluated for their antibacterial activities against Gram-positive and Gram-negative bacteria. The catalytic activity of 3 was also studied, and as a result, the in situ prepared three component system Ru(II)/3/KOH is shown to be an efficient catalyst for the transfer hydrogenation reaction of various ketones under mild conditions. Compound 3 has been crystallized in two polymorphic forms under the same conditions, and their crystal structures have been determined using single crystal X-ray diffraction technique. The molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of 3 in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-31G(d) basis set, and compared with the experimental data. The results are in good agreement with experimental data. The effect of different solvents on the geometry, vibrational frequencies, total energies and dipole moments was also studied using the same method by applying the Onsager Model. There are subtle differences in the conformations and packing of the two polymorphs as a consequence of intermolecular hydrogen bonding interactions. Therefore, DFT calculations for the hydrogen bond interactions in the polymorphs were carried out using same basis set. The changes of thermodynamic properties from the monomers to 3 with the temperature ranging from 200 K to 400 K have been obtained using the statistical thermodynamic method.

Bis{2,6-bis[1-(4-fluorophenylimino)ethyl]pyridine}-1kappa3N,N',N'';3kappa3N,N',N''-di-mu-chlorido-1:2kappa2Cl:Cl;2:3kappa2Cl:Cl-trichlorido-1kappaCl,2kappaCl,3kappaCl-2-copper(I)-1,3-dicopper(II).

The title complex, [Cu3Cl5(C21H17N3F2)2], is the first reported copper trimer including both Cu(I) and Cu(II) ions. The two Cu(II) ions are five-coordinate in a significantly distorted square-pyramidal arrangement, with the bridging Cl atom located in the apical position, and the pyridine (py) N atom, the two imine N atoms and the other Cl atom located in the basal plane. The Cu(I) ion is in a trigonal planar configuration surrounded by three Cl atoms. The structure is stabilized by intra- and intermolecular C-H...Cl and C-H...pi(py) hydrogen bonds.

Photocharacterization of novel ruthenium dyes and their utilities as oxygen sensing materials in presence of perfluorochemicals.

Photophysical constants of three novel ruthenium dyes derived from tridentate pyridinediimine (pydim) ligands has been declared and their photoluminescent properties were investigated in solvents of dichloromethane (DCM), tetrahydrofuran (THF) and ethanol (EtOH) by UV-Visible absorption, emission and excitation spectra. The quantum yield, fluorescence decay time, molar extinction coefficient and Stoke's shift values of the novel ruthenium complexes were determined. The perfluoro compound (PFC) nonadecafluorodecanoic acid which is also known as medical gas carrier has been used for the first time together with newly synthesized Ruthenium complexes in ethyl alcohol. The utilities of oxygen sensing materials were investigated in EtOH in presence of chemically and biochemically inert PFC.

(Acetonitrile){2,6-bis[1-(2,4,6-trimethylphenylimino)ethyl]pyridine}dichloridoruthenium(II) dichloromethane solvate.

In the title compound, [RuCl2(C(2)H(3)N)(C(27)H(31)N(3))].CH(2)Cl(2), the Ru(II) ion is six-coordinated in a distorted octahedral arrangement, with the two Cl atoms located in the apical positions, and the pyridine (py) N atom, the two imino N atoms and the acetonitrile N atom located in the basal plane. The two equatorial Ru-N(imino) distances are almost equal (mean 2.087 A) and are substantially longer than the equatorial Ru-N(py) bond [1.921 (4) A]. It is observed that the N(imino)-M-N(py) angle for the five-membered chelate rings of pyridine-2,6-diimine complexes is inversely related to the magnitude of the M-N(py) bond. The title structure is stabilized by intra- and intermolecular C-H...Cl hydrogen bonds, as well as by van der Waals interactions.

(2,6-Bis[1-[4-(dimethylamino)phenylimino]ethyl]pyridine)dichlorido(triphenylphosphine-kappaP)ruthenium(II): a zigzag chain of fused centrosymmetric R(2)(2)(12) rings.

The title compound, [RuCl(2)(C(25)H(29)N(5))(C(18)H(15)P)], a transfer hydrogenation catalyst, is supported by an N,N',N''-tridentate pyridine-bridged ligand and triphenylphosphine. The Ru(II) centre is six-coordinated in a distorted octahedral arrangement, with the two Cl atoms located in the axial positions, and the pyridine (py) N atom, the two imino N atoms and the triphenylphosphine P atom located in the equatorial plane. The two equatorial Ru-N(imino) distances (mean 2.093 A) are substantially longer than the equatorial Ru-N(py) bond [1.954 (4) A]. It is observed that the N(imino)-M-N(py) bond angle for the five-membered chelate rings of 2,6-bis(imino)pyridine-based complexes is inversely related to the magnitude of the M-N(py) bond. The title structure is stabilized by intra- and intermolecular C-H...Cl hydrogen bonds, as well as by intramolecular pi-pi stacking interactions between the aromatic rings belonging to the triphenylphosphine ligand and the dimethylaminophenyl fragment. The intermolecular hydrogen bonds form an R(2)(2)(12) ring and a zigzag chain of fused centrosymmetric rings running parallel to the [100] direction.

(2Z,6Z)-N,N-Bis(2,6-diisopropyl-phen-yl)-N,N-bis-(2-methoxy-ethyl)pyridine-2,6-dicarboxamidine.

In the title compound, C(37)H(53)N(5)O(2), the benzene rings make dihedral angles of 84.61 (8) and 67.10 (9)° with the pyridine ring. The crystal structure is stabilized by strong intra-molecular inter-actions. The two (2-methoxyethyl)amine groups are disordered over two positions; the site occupancies are ca 0.6 and 0.4.

Dichloro[(1E,1'E)-1,1'-(pyridine-2,6-diyl)diethanone bis(O-methyloxime)-kappa3N1,N2,N6]cobalt(II).

In the title compound, [CoCl2(C11H15N3O2)], the CoII ion is five-coordinated in a strongly distorted square-pyramidal arrangement, with one of the two Cl atoms located in the apical position, and the other Cl atom and the three N-donor atoms of the tridentate methyloxime ligand located in the basal plane. The non-H atoms, except for the Cl atoms, lie on a mirror plane. The two equatorial Co-Noxime distances are almost equal (mean 2.253 A) and are substantially longer than the equatorial Co-Npyridine bond [2.0390 (19) A]. The structure is stabilized by intra- and intermolecular C-H...Cl contacts, which involve one of the methyl C atoms belonging to the methyloxime groups.

Dichloro[(1E,1'E)-1,1'-(pyridine-2,6-diyl)diethanone bis(O-methyloxime)-kappa(3)N(1),N(2),N(6)]copper(II).

In the title compound, [CuCl(2)(C(11)H(15)N(3)O(2))], the Cu(II) ion is five-coordinated in a strongly distorted trigonal-bipyramidal arrangement, with the two methyloxime N atoms located in the apical positions, and the pyridine N and the Cl atoms located in the basal plane. The two axial Cu-N distances are almost equal (mean 2.098 A) and are substantially longer than the equatorial Cu-N bond [1.9757 (15) A]. It is observed that the N(oxime)-M-N(pyridine) bond angle for five-membered chelate rings of 2,6-diacetylpyridine dioxime complexes is inversely related to the magnitude of the M-N(pyridine) bond. The structure is stabilized by intra- and intermolecular C-H...Cl hydrogen bonds which involve the methyl H atoms, except for one of the two acetylmethyl groups.