Tris-chelate complexes of cobalt(III) with N-[di(alkyl/aryl)carbamothioyl] benzamide derivatives: Synthesis, crystallography and catalytic activity in TBHP oxidation of alcohols
摘要:
New six coordinated tris-chelate cobalt(III) complexes of the type [Co(L)(3)] (1-4) {where HL = N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives} were prepared from the reaction between CoCl2 center dot 6H(2)O and N-[di(alkyl/aryl)carbamothioyl]benzamide in ethanol and characterized by elemental analysis and spectral data (UV/Vis, IR,H-1 & (CNMR)-C-13). The molecular structure of a representative complex [Co(L1)(3)] (1) [where HL1 = N-(diisopropylcarbamothioyl)benzamide], was determined by single crystal X-ray diffraction method and reveals a distorted octahedral geometry and a facial configuration of S atoms around the Co(III) center. These complexes act as efficient catalysts for the oxidation of alcohols to their corresponding aldehydes or ketones in presence of tert-butyl hydroperoxide (TBHP) at 80 degrees C. (C) 2011 Elsevier B.V. All rights reserved.
The complexes of 8 N,N-disubstituted,N'-benzoyl thioureas with copper, nickel and cobalt have been studied. NMR spectra and magnetic measurements have shown square planar NiL2 and fac CoL3 compounds. The electrochemical parameters obtained from cyclic voltammetry for the irreversible process copper(II)/copper(I) redox systems are slightly influenced by the different substituents.