Electronic structure calculations on multiply charged anions containing MS bonds (M = Cr, Mo, W) and their heterobimetallic cluster complexes

Abstract

AbstractMolecular and electronic structures of multiply charged mononuclear [CrS4]2−/3−, [MoOxS4−x]2−/3− (x = 0–4) and [WS4]2−/3− anionic species, and their heterobimetallic dinuclear and trinuclear clusters formulated as [MoOS3(CuCl)]2−, [WOS3(CuCl)]2−, [MoS4{Cu(CN)}]2−, [(CN)Cu(μ‐CrS4)Cu(CN)]2−, [(CN)Cu(μ‐MoS4)Cu(CN)]2−, [ClCu(μ‐MoS4)CuCl]2−, [Cl2Fe(μ‐MoS4)CuCl2]2−, and [(CN)Cu(μ‐WS4)Cu(CN)]2− have been investigated using electronic structure calculation (HF, MP4SDQ and DFT) methods. For the discrete mononuclear anions HF/lanl2dz(M)∪6‐31+G*(S,O) method provided the best description of their molecular structures, while for the heterobimetallic dinuclear and trinuclear clusters the B3LYP/lanl2dz(M)∪6‐31+G* method gave equilibrium geometries closely resembling the experimental ones. Electronic and spectroscopic (IR, UV‐Vis) properties of the thiometalates are discussed in relation to their structures, while the bonding mechanism was analyzed in the framework of the natural bond orbital (NBO) approach. The nature of the highest occupied molecular orbitals (HOMOs) of all thiometalates indicated their ability to act as ligands coordinated with metal centers and forming clusters of higher nuclearity. The lowest‐lying vertical one‐electron detachment processes from the ground state of the [CrS4]2/3−, [MoOxS4−x]2/3− (x = 0–4) and [WS4]2/3− anions have been calculated using the outer valence Green's function (OVGF) method. Interestingly, in the heterobimetallic dinuclear and trinuclear clusters intemetallic M…M′ interactions exist corresponding to d10 → d0 dative bonding. Finally, the complete energetic and geometric profile of the successive acid‐catalyzed formation reactions: equation image and the reverse hydrolysis reactions have been delineated and details of the mechanism have been furnished. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007