Thermolysis of some carbamatotetracarbonyl- and carbamatopentacarbonyl-rhenium(I) complexes in the solid state and in solution

Abstract

A series of carbamatocarbonylrhenium(I) complexes, [Re(CO)₄(XYCNMe₂)](XY = SS, SSe, or SeSe) and [Re(CO)₅{X(O)CNMe₂}](X = S or Se), has been prepared. Thermolysis of these complexes in the solid state under flowing nitrogen or carbon monoxide affords binuclear complexes doubly bridged by sulphur or selenium, [{Re(CO)₃(XYCNMe₂)}₂], [{Re(CO)₄[X(O)CNMe₂]}₂], and [{Re(CO)₃[X(O)CNMe₂]}₂], as confirmed by i.r. and mass spectroscopy. Infrared spectra also reveal that [{Re(CO)₃[S(O)CNMe₂]}₂] adopts a syn configuration while the other dirhenium complexes assume anti forms. The complex [Re(CO)₅{X(O)CNMe₂}] also undergoes thermolysis in cyclohexane to yield the same product as in the solid state; a mechanism is presented on the basis of time-dependent i.r. spectra.