Search

The reactions of Me(Ph)SnCl2 and Et(Ph)SnCl2 with 2,6-diacetylpyridine bis(thiosemicarbazone) (H2DAPTSC) afforded the complexes [Me(Ph)Sn(HDAPTSC)]Cl · 1.25MeOH (1) and [Et(Ph)Sn(H2DAPTSC)]Cl2 · MeOH · H2O (2), respectively. Single-crystal X-ray crystallography showed that in both complexes the ligand, monodeprotonated in 1 and neutral in 2, is S(1),S(2),N(3),N(4),N(5)-coordinated, and the coordination geometry around the metal can be described as a distorted pentagonal bipyramid with the aryl and alkyl groups in axial positions. 1H and 119Sn NMR studies of solution in DMSO suggest that 2 dissociates completely in this solvent, while 1 evolves to the new complex [Me(Ph)Sn(DAPTSC)], with release of H2DAPTSC and Me(Ph)SnCl2. These conclusions were also supported by conductivity measurements. Complexes of R(Ph)SnCl2 (R=Me, Et) with 2,6-diacetylpyridine bis(thiosemicarbazone) have been synthesized and characterized by X-ray crystallography, 1H and 119Sn NMR spectroscopy and conductivity measurements. The crystal structures of [Me(Ph)Sn(HDAPTSC)]Cl · 1.25MeOH (1) and [Et(Ph)Sn(H2DAPTSC)]Cl2 · MeOH · H2O (2) contain the ligand, monodeprotonated or neutral, acting as pentadentate. NMR studies in DMSO solution suggest the total dissociation of (2), whereas (1) evolves to form the new complex [Me(Ph)Sn(DAPTSC)]. [Copyright &y& Elsevier]

Methylmercury(II) xanthates, MeHgS(S)COR, with R=Et, iPr and CH2Ph, form unidimensional, supramolecular self-assembled, tape-like arrays in the solid state, based upon Hg⋯S intermolecular secondary interactions. In the compounds with R=Et and iPr the individual molecules form double chains (tapes) weakly interacting with neighbouring arrays, while the compound with R=CH2Ph forms dimeric units, which are further associated into infinite tapes, not interacting with each other. Primary Hg&z.sbnd;S bonds are in the range 2.378(5)–2.391(3) A˚, intramolecular Hg⋯S secondary bonds leading to chelation are in the range 3.179(5)–3.259(3) A˚, whereas intermolecular Hg⋯S secondary interactions cover a broader range, from 3.403(4) to 4.22(1) A˚. [Copyright &y& Elsevier]

Abstract: Four new ternary complexes of copper(I) with thiosaccharin and phosphanes were prepared. The reaction of [Cu4(tsac)4(CH3CN)2] (1) (tsac: thiosaccharinate anion) with PPh3 in molar ratios Cu(I)/PPh3 1:075 and 1:2 gave the complexes [Cu4(tsac)4(PPh3)3]·CH3CN (2) and Cu(tsac)(PPh3)2 (3), respectively. The reaction of 1 with Ph2PCH2PPh2 (dppm) in molar ratios Cu(I)/dppm 2:1 and 1:1 gave the complexes [Cu4(tsac)4(dppm)2]·2CH2Cl2 (4) and [Cu2(tsac)2(dppm)2]·CH2Cl2 (5), respectively. All the compounds have been characterized by spectroscopic and X-ray crystallographic methods. Complex 2 presents a tetra-nuclear arrangement with three metal centers in distorted tetrahedral S2NP environments, the fourth one with the Cu(I) ion in a distorted trigonal S2N coordination sphere, and the tsac anions acting as six electron donor ligands in μ3-S2N coordination forms. Complex 3 shows mononuclear molecular units with copper(I) in a distorted trigonal planar coordination sphere, built with the exocyclic S atom of a mono-coordinated thiosaccharinate anion and two P-atoms of triphenylphosphane molecules. With dppm as secondary ligand the structures of the complexes depends strongly on the stoicheometry of the preparation reaction. Complex 4 has a centrosymmetric structure. Two triply bridged Cu2(tsac)2(dppm) units are joined together by the exocyclic S-atoms of two tsac anions acting effectively as bridging tridentate ligands. Complex 5 is conformed by asymmetric dinuclear moieties where the two dppm and one tsac ligands bridge two Cu(I) atoms and the second tsac anion binds one of the metal centers through its exocyclic S-atom. [Copyright &y& Elsevier]

Abstract: Spectroscopic (IR, 31P NMR and UV–Vis) and electrochemical studies on fac-[Mn(CO)3(L′–L′)(L)]0/+,where L′–L′=1,2-bis(diphenylphosphino)ethane (dppe) or 1,10-phenanthroline (phen) and L=bromide, triflate, imidazole (im), isonicotinamide (isn) or N-(2-hydroxyethyl)isonicotinamide (heisn), were undertaken to understand the effect of various ligands on the CO–Mn–L and CO–Mn–(L′–L′) bonding characteristics of these complexes. Crystal structures for L=triflate/L′–L′=dppe, L=triflate/L′–L′=phen and L=isn/L′–L′=phen are reported and they show that the two Mn–O(OSO2CF3) and Mn–N(isn) distances are similar. The tricarbonyl complexes exhibit two major bands in the 250–300 and 350–450 nm region of the UV–Vis spectrum. The lowest energy bands have been assigned as a contribution from both the metal-centered (MC) and metal to ligand (dπ →L′–L′) charge transfer (MLCT) transitions. The energy of this maximum absorption decreases in the order Br− ∼triflate>im>isn∼heisn. The cyclic four-component mechanism was observed at room temperature by voltammetric techniques for all the cases. On the basis of d metal orbital splitting, an electronic molecular orbital diagram is proposed. In this model, the ligands along the z-axis play a relevant role in the reverse of the HOMO energies of the fac/mer isomers by stabilizing the metal orbital relative to d xy in mer-Mn(II). [Copyright &y& Elsevier]