Kandasamy Sivakumar

Synthesis and spectral studies on Ru3(CO)12−n(μ-Ph2AsCH2AsPh2)(L) (n = 3, L : PPh3, PCy2Ph,P(OCH3)3); n = 4, L = Ph2PCH2PPh2) : crystal and molecular structures of Ru3(CO)9(μ-Ph2AsCH2AsPh2)(PCy2Ph) and Ru3(CO)8(μ-Ph2AsCH2AsCH2AsPh2)μ-Ph2PCH2PPh2)

Abstract Mixed ligand triangulotriruthenium cluster carbonyls, Ru3(CO)9(μ-Ph2AsCH2AsPh2)(L) (L = PPh3, PCy2Ph, P(OCH3)3) and Ru3(CO)8(μ-Ph2AsCH2AsPh2)(μ-Ph2PCH2PPh2) were synthesised and characterised by microanalysis, IR, 1H, 13C and 31P NMR spectrometry. Single crystal X-ray structure determination of Ru3(CO)9(μ-Ph2AsCH2AsPh2)(PCy2Ph) and Ru3(CO)8(μ-Ph2AsCH2AsPh2(μ-Ph2PCH2PPh2) are reported. In both the clusters, the triruthenium framework is planar. In Ru3(CO)9(μ-Ph2AsCH2AsPh2)(PCy2Ph), the monodentate phosphine occupies an equatorial position for steric reasons. The effect of trisubstitution is explicit in the highly significant differences observed in Ruue5f8Ru distances (2.8301 (6), 2.8653(7) and 2.8873(7) A) in the present compound compared to Ru3(CO)10(μ-Ph2AsCH2AsPh2). The observed Ruue5f8As distances are 2.4508(7) and 2.4331(7) A respectively and the Ruue5f8P distance is 2.362(1) A. In the case of Ru3(CO)8(μ-Ph2AsCH2AsPh2)(μ-Ph2PCH2PPh2), the chelating ligands occupy four equatorial positions. Two of the Ruue5f8Ru distances are similar in length (2.848(2), 2.850(2) and 2.828(2) A). However, positional disorder is associated with As and P atoms. Other bond parameters are normal.

A novel, more vivid Cu2Zn2SOD model: crystal structure and some properties of the Schiff base copper(II) complex: [Cu(appn)](ClO4)2·H2O

Abstract The novel Cu2Zn2 superoxide dismutase (Cu2Zn2SOD) mimic compound [Cu(appn)](ClO4)2·H2O [where appn = N,N′-propylenebis(2-actoylpyridineiminato)] has been prepared. Single-crystal X-ray analysis revealed that the copper(II) ion has a distorted square-pyramidal environment very similar to that of Cu2Zn2SOD: the basal positions are occupied by four nitrogen atoms from the Schiff base ligand and the apical position by an oxygen atom of a hydrate molecule. The Cuue5f8N and Cuue5f8O bond lengths are 1.972(2)…2.029(2) and 2.326(2)A, respectively.

Symmetrically substituted thiourea derivatives

The crystal structures of three symmetrically substituted thiourea derivatives, 1,3-diethylthiourea (DETU), C 5 H 12 N 2 S, 1,3-diisopropylthiourea (DIPTU), C 7 H 16 N 2 -S, and 1,3-diphenylthiourea (DPTU), C 13 H 12 N 2 S, are reported. N-H...S hydrogen bonds link the molecules into two-dimensional networks in DETU and DIPTU and into one-dimensional chains in DPTU. DETU and DIPTU have the same mode of packing in the crystal lattice.

A novel molecular channel: thermal analyses and X-ray structure of [Ni(Et-XA)2 · phen] · 3H2O (Et-XA = ethylcarbonodithiolato-S,S′, phen = phenanthroline)

Abstract The crystal structural determination reveals that bis(o-ethylcarbonodithiolato-S,S′)(1,10-phenanthroline-N1,N10)nickel(II) ([Ni(Et-XA)2 · phen] · 3H2O) forms a lattice inclusion compound with water molecules trapped in channels and grouped into triplets, within which exist very strong hydrogen bonds. The thermal analyses further confirms that the structure appears to be very stable and release of water molecules can be achieved only by the rupture of structure.

Preparation and characterization of metal complexes containing a NS donor ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde. X-ray crystal structure of the nickel(II) chelate

SummaryA series of metal (Cu, Ni, Zn, Cd and Pd) complexes of a Schiff base ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde were prepared and characterized. The Schiff base acts as a single negatively-charged bidentate ligand forming stable neutral metal complexes. Magnetic and spectroscopic data suggest a square planar structure for the CuII, NiII and PdII chelates. Single X-ray diffraction analysis of the NiII chelate established that the Schiff base loses a proton from its tautomeric thiol form and coordinates to the metal via the thiolato sulfur and β-nitrogen. The geometry around NiII is square planar with two equivalent Ni-N and Ni-S bonds; the two nitrobenzyl rings and the coordination plane are almost isoplanar, giving a delocalized electronic system.

Benzyl 3-(4-Dimethylaminobenzylidene)dithiocarbazate

The title Schiff base compound, C 17 H 19 N 3 S 2 , crystallizes in the triclinic system with two molecules in the asymmetric unit. The dimethylaminophenyl and carbazate parts of the molecule lie in one plane, perpendicular to the plane of the S-benzyl group. One of the two molecules in the asymmetric unit displays lateral disorder of the S-benzyl group. The molecular packing is governed by N-H...S hydrogen bonds leading to the formation of dimeric pairs of the same type, i.e. pairs of either normal or disordered molecules.

(N‐Pyrrolidinecarbodithioato‐S,S')bis(triphenylphosphine)silver(I)

In the title compound, [Ag(C 5 H 8 NS 2 )(C 18 H 15 P) 2 ], the Ag atom is tetrahedrally surrounded by the two P atoms of the triphenylphosphine groups and the two S atoms of the bidentate pyrrolidinecarbodithioate ligand. The coordination polyhedron is severely distorted ; the S-Ag-S angle is 68.15 (4)° and the remaining angles are in the range 107.23 (3)-124.43 (3)°. The pyrrolidine ring adopts an envelope conformation.

Hydrogen bis[(8-quinolinol-N-(8-quinolinolato-N,O)(triphenylphosphine-P)silver(I)] acetate monohydrate

The asymmetric unit of the title compound, [Ag 2 H-(C 9 H 6 NO) 2 (C 9 H 7 NO) 2 (C 18 H 15 P) 2 ](C 2 H 3 O 2 ).H 2 O, contains two exactly centrosymmetric [QHQ] + complex cations, Q = [Ag(PPh3)(C 9 H 6 NOH)(C 9 H 6 NO)]. The two electroneutral silver complex units, Q, in each cation are connected by a short hydrogen bond [O...O 2.452 (5) and 2.463 (6) A], with the proton lying at an inversion center. Each Ag atom has a distorted tetrahedral environment, bonding to two quinoline ligands and a PPh 3 ligand; both O and N atoms of the anionic quinolinol ligand are attached to the Ag atom, while in the neutral quinolinol ligand, the bonding is only through the N atom. The fourth coordination site is occupied by the P atom of a PPh 3 ligand. Some differences in the coordination of the two independent Ag atoms are observed. The [QHQ] + complex cations are linked by the trapped acetate ions through hydrogen bonding which also connects the water molecule to one of the acetate O atoms. In each [QHQ] + cation, there are intramolecular contacts between the Ag and the phenolic O atom of the neutral quinolinol moieties [Ag...O 2.827 (4) and 2.901(4) A].

(Thiocyanato-N)tris(triphenylphosphine)-silver(I) chloroform solvate

Crystals of [Ag(NCS)(C18H15P)3].CHCl3 consist of discrete [Ag(PPh3)3(NCS)] molecules, in which the Ag atom is tetrahedrally surrounded by three P atoms of the PPh3 groups and the N atom of the isothiocyanate ligand, and chloroform molecules. The coordination polyhedron around the Ag atom is distorted with angles at Ag ranging from 102.58u2005(10) to 114.73u2005(3)°. The Ag—N—C angle is 159.6u2005(3)°.

Synthesis and structural characterization of two interesting sandwich and double sandwich type mixed-valent tellurium-dithiocarbamate complexes;[TeIV {S2CN(C2H5)2}3]2 [TeIV{S2CN(C2H5)2}3](PF6)2 and [TeIV{S2CN(C2H5)2}3] [TeII{S2CN(C2H5)2}2](ClO4)

Abstract Two novel mixed-valent tellurium(II and IV) dithiocarbamate complexes have been prepared and their structures determined by X-ray diffraction studies. Complex 1, [TeIV(S2CNEt2)3]2[TeII(S2CNEt2)2](PF6)2, was obtained from the metathesis reaction of [TeIV(S2CNEt2)3ClO4] with KPF6 due to the partial reduction of the primary product [TeIV(SCNEt2)3]PF6, which is thermodynamically unstable. The preparation of tellurium(IV) dithiocarbamate in dilute perchloric acid medium results in complex 2, which has a composition [TeIV(S2CNEt2)3][TeII(S2CNEt2)2](ClO4). These two complexes represent the first examples of mixed valent complexes of tellurium consisting only the sulphur ligands. Their structural investigation shows that these complexes are stabilized primarily due to the supramolecular Te3.Te interaction, the distance of which is shorter than the earlier known complex. While TeII(S2CNEt2)2 is sandwiched between two TeIV(S2CNEt2)3 molecules in 1, two such Te(II) molecules are sandwiched in complex 2.