An Exploration of the Structural and Bonding Variability in Mixed-Ligand Benzimidazole-2-thione(bromo)(triarylphosphane)dicopper(I) Complexes with Diamond-Shaped Cu2(μ-X)2 Core Structures
✍ Scribed by Sotiris K. Hadjikakou; Constantinos D. Antoniadis; Paraskevas Aslanidis; Philip J. Cox; Athanassios C. Tsipis
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 289 KB
- Volume
- 2005
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
Reaction of copper(I) bromide with benz‐1,3‐imidazole‐2‐thione (bzimtH~2~) in the presence of one equivalent of triphenylphosphane (PPh~3~), tri‐meta‐tolylphosphane (tmtp) or tri‐para‐tolylphosphane (tptp) in acetonitrile/methanol solvent afforded dinuclear complexes formulated as [CuBr(bzimtH~2~)(PR~3~)]~2~. The new complexes were characterized by IR, UV/Vis, and ^1^H NMR spectroscopy, while the crystal structures of [{CuBr(μ~2~‐S‐bzimtH~2~)(PPh~3~)}~2~]~0.78~[{Cu(μ~2~‐Br)(PPh~3~)(bzimtH~2~)}~2~]~0.22~ (1), [CuBr(μ~2~‐S‐bzimtH~2~)(tmtp)]~2~ (2) and [CuBr(μ~2~‐S‐bzimtH~2~)(tptp)]~2~ (3) were determined by single‐crystal X‐ray diffraction methods. In complex 1, with spectator PPh~3~ ligands, the unit cell of the crystal consists of two different half‐molecules, both corresponding to the formula [CuBr(bzimtH~2~)(PPh~3~)]~2~. One of the two molecules (molecule A) is a symmetrical dicopper(I) complex in which the exocyclic thione S‐atoms serve as bridges between the Cu^I^ ions. The second one (molecule B) is disordered and can be resolved into two separate entities, one μ~2~‐S dicopper(I) complex, similar to molecule A (molecule B1), and another one (molecule B2) involving μ~2~‐Br bridges. In contrast, in complexes 2 and 3, with spectator tmtp and tptp ligands, only the bzimtH~2~‐bridged dicopper complexes are formed. Density functional calculations at the B3LYP level of theory provided a satisfactory description of the structural, bonding, electronic and related properties of all dicopper complexes exhibiting the “diamond‐shaped” Cu~2~(μ‐X)~2~ (X = S or Br) core structures and account well for their structural preferences. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)