Renu Sachar

Bis(O-ethyl dithio-carbonato-κS,S')bis-(pyridine-3-carbonitrile-κN)nickel(II).

The Ni2+ ion in the title complex, [Ni(C3H5OS2)2(C6H4N2)2], is in a strongly distorted octahedral coordination environment formed by an N2S4 donor set, with the Ni2+ ion located on a centre of inversion. In the crystal, weak C—H⋯S and C—H⋯N interactions are observed.

Characterization of the adducts of bis(O-isoamyldithiocarbonato)nickel(II) with heterocyclic amines and X-ray structure of bis(O-isoamyldithiocarbonato)-bis(3-bromopyridine)nickel(II)

A series of six-coordinated Ni(II) complexes, with the general formula Ni(Xan)L2 (where Xan = = isoamyldithiocarbonato and L = 2-bromopyridine, 3-bromopyridine, 4-acetylpyridine, 3-hydroxypyridine and 2-methoxypyridine) are synthesized and characterized by the elemental analysis and various physicochemical techniques such as magnetic susceptibility and conductivity measurements, UV-visible and infrared spectral data. Based on the electronic spectra and magnetic susceptibility measurements, an octahedral geometry is proposed for all the complexes. IR spectral data show that in all these complexes substituted pyridines coordinate to the metal ion through nitrogen atoms occupying the fifth and sixth axial positions, whereas O-alkyldithiocarbonate acts as a monoanion bidentate ligand and occupies the planar positions of octahedral structures. The structure of the adduct with 3-bromopyridine is elucidated by the single crystal X-ray diffraction method. The complex crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.5855(4) Å, b = 9.4984(6) Å, c = 12.4518(8) Å, α = 87.944(5)°, β = 78.843(5)°, γ = 77.794(5)°. The crystal structure of the molecule is stabilized by intermolecular C–H…S and C–H…π interactions.

Crystal structure of bis­(3-bromo­pyridine-κN)bis­(O-ethyl di­thio­carbonato-κ2S,S′)nickel(II)

In the title molecular complex, [Ni(C3H5OS2)2(C5H4BrN)2], the Ni2+ cation is located on a centre of inversion and has a distorted octahedral N2S4 environment defined by two chelating xanthate ligands and two monodentate pyridine ligands. The C—S bond lengths of the thiocarboxylate group are indicative of a delocalized bond and the O—Csp 2 bond is considerably shorter than the O—Csp 3 bond, consistent with a significant contribution of one resonance form of the xanthate anion that features a formal C=O+ unit and a negative charge on each of the S atoms. The packing of the molecules is stabilized by C—H⋯S and C—H⋯π interactions. In addition, π–π interactions between the pyridine rings [centroid-to-centroid distance = 3.797 (3) Å] are also present. In the crystal structure, molecules are arranged in rows along [100], forming layers parallel to (010) and (001).

Synthesis, Characterization, and X-Ray Crystal Structure of Bis(O-amyl dithiocarbonato-κ2S,S′)bis(4-cyanopyridine-κN)nickel(II)

The [Ni(S2CO-n-C5H11)2(C6H4N2)2] adduct of 4-cyanopyridine with [Ni(S2CO-n-C5H11)2] was synthesized and characterized by elemental analysis, magnetic susceptibility measurement, IR, electronic spectral data, and X-ray diffraction analysis. The Ni atom in the title complex is octahedrally coordinated within a trans-N2S4 donor set, with the Ni atom located on a centre of inversion. The title compound exhibits magnetic moment value (3.20 B.M) which is in agreement with magnetic moment values observed for paramagnetic octahedral complexes of nickel(II). The title complex crystallizes in the orthorhombic space group Pbca with unit cell parameters a = 11.455(5), b = 9.602(4), and c = 26.374(1) A. Crystal structure was solved by direct methods and refined by full matrix least-squares procedures to a final R value of 0.0499 for 2004 observed reflections. The amyl chain is disordered over two sets of sites, with occupancy ratios of 0.595 : 0.405. Infinite long chains of molecules are formed with the help of C–H⋯N hydrogen bond.

Synthesis, Characterization, and X-Ray Structure of Bis(O-butyldithiocarbonato)bis(3-ethyl pyridine)nickel(II)

A new series of additional complexes of bis(O-butyldithiocarbonato)nickel(II) with ethylpyridines have been prepared and characterized by physicochemical techniques like elemental analysis, molar conductance measurements, TGA-DTA and UV-visible electronic spectroscopy, and IR-spectral data. The structure of [Ni(S2COC4H9)2(C7H9N)2] has been established by X-ray crystallography. The complex crystallizes in the monoclinic space group P1/n with unit cell parameters , , and A and , , and °. The Ni atom in the title complex is octahedrally coordinated within a trans-N2S4 donor set, with the Ni atom located on a centre of inversion. Crystal structure was solved by direct methods and refined by full matrix least squares procedures to a final -value of 0.0545 for 1984 observed reflections. The butyl chain is disordered over two sets of sites, with occupancy ratio of 0.572 : 0.427.

Synthesis and Characterization of the Adducts of Bis(O-ethyldithiocarbonato)copper(II) with Substituted Pyridines

Monomeric five coordinated adducts of bis(O-ethyldithiocarbonato)copper(II) of general formula [Cu(C2H5OCS2)2(L)], [L = 2-, 3-, 4-methylpyridines and 2-, 3-, 4-ethylpyridines] have been synthesized and characterized by elemental analysis, i.r. and electronic spectroscopy, magnetic and conductivity measurements. Analytical results show that the adducts have 1 : 1 stoichiometry. The adducts were found to be paramagnetic and their magnetic moments at room temperature lie within the 1.81–1.94 B.M. range and this indicates the presence of one unpaired electron. All the adducts have distorted square pyramidal geometry.