Tris-chelate complexes of cobalt(III) with N-[di(alkyl/aryl)carbamothioyl] benzamide derivatives: Synthesis, crystallography and catalytic activity in TBHP oxidation of alcohols

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 CoCl2·6H2O and N-[di(alkyl/aryl)carbamothioyl]benzamide in ethanol and characterized by elemental analysis and spectral data (UV/Vis, IR, 1H & 13C NMR). 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 °C.

Graphical abstractNew tris-chelate Co(III) complexes containing N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives have been synthesized and characterized. These complexes exhibited good catalytic activity for oxidation of alcohols to carbonyl compounds in presence of tert-butyl hydroperoxide (TBHP) at 80 °C.Figure optionsDownload full-size imageDownload high-quality image (105 K)Download as PowerPoint slideHighlights► Efficient oxidation of alcohols to carbonyl compounds in presence of tert-butyl hydroperoxide. ► Benzylic and cyclic alcohols are oxidized efficiently. ► Tris-chelate cobalt(III) complexes containing N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives may emerge as an effective catalytic system for various organic transformations. ► Molecular structure of tris-chelate cobalt(III) complex containing N-[diisopropylcarbamothioyl]benzamide was determined by X-ray crystallography.