902121-38-4Relevant articles and documents
An experimental and theoretical (DFT) investigation of the coordination mode of 2,4-dithiouracil (2,4-dtucH2) in copper(I) complexes with 1,2-bis(diphenylphosphanyl)benzene (dppbz): The crystal structures of [Cuμ-Br(dppbz)]2 and [CuBr(dppbz)(2,4-dtucH2)]
Aslanidis, Paraskevas,Cox, Philip J.,Kaltzoglou, Andreas,Tsipis, Athanasios C.
, p. 334 - 344 (2007/10/03)
Novel copper(I) mixed-ligand complexes containing 1,2- bis(diphenylphosphanyl)benzene (dppbz) and 2,4-dithiouracil (2,4-dtucH 2) ligands have been synthesised by addition of the thione ligand to the dinuclear [Cu(μ-X)(dppbz)]2 intermediate in acetonitrile/methanol or acetone solution. The molecular structures of both the precursor [Cu(μ-Br)(dppbz)]2 and the [CuBr(dppbz)(2,4-dtucH 2)] complexes were established by single-crystal X-ray diffraction. Interestingly, the structure of the thione-free dimer involves two diphosphanechelated CuI centres bridged by two bromide ligands, thus forming a non-planar Cu2Br2 core. The structure of [CuBr(dppbz)(2,4-dtucH2)] corresponds to a four-coordinate CuI centre in a tetrahedral coordination environment with the heterocyclic dithione ligand being coordinated to the metal centre in a unidentate fashion through its exocyclic sulfur donor atom. The structural, bonding and electronic properties of the model complexes [Cu(μ-X)(dppbz)]2 and [CuX(dppbz)(2,4- dtucH2)] (X = Cl, Br, or I) are adequately described by DFT/B3LYP computational techniques. All model dinuclear [Cu(μ-X)(dppbz)]2 complexes exhibit π-type MOs delocalised over the entire four-membered Cu(μ-X)2Cu ring, thereby accounting for the near equivalency of the Cu-X bonds. Moreover, the [Cu(μ-X)(dppbz)]2 dimers possess a σ-type MO corresponding to weak Cu...Cu bonding interactions, which further stabilize the Cu(μ-X)2Cu ring. According to our calculations, the interaction energies of the 2,4-dtucH2 ligand with the CuI centre are predicted to be about 13-16 kcalmol-1. The coordination of the 2,4-dtucH2 ligand is further stabilized by an X...H-N hydrogen bond that is perpendicular to the plane of the dppbz ligand. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
