Reaction of CS2 with a ligand-bridged dicobalt complex: crystal and molecular structures of [Co2{µ-PPh2CHC(SiMe3)C(O)CS}(µ-PPh2S)(CO)3] and [Co2(µ-PPh2CHCPhCS)(µ-PPh2S)(CO)3]

Abstract

Thermolysis of [Co₂{µ-PPh₂CHCRC(O)}(µ-PPh₂)(CO)₄](R = SiMe₃1a or Ph 1b) in CS₂ affords the complexes [Co₂{µ-PPh₂CHCRC(O)CS}(µ-PPh₂S)(CO)₃](R = SiMe₃2a or Ph 2b) in ca. 40–50% yield. In the case of 1b a complex with the formula [Co₂(µ-PPh₂CHCPhCS)(µ-PPh₂S)(CO)₃]3b was also isolated in ca. 8% yield. X-Ray diffraction studies on complexes 2a and 3b reveal in both cases that cleavage of a carbon–sulfur bond in a CS₂ molecule and insertion of the resulting CS and S fragments into respectively Co–C and Co–P bonds have occurred. In each case also the carbon–carbon double bond of the metallacyclic bridging ligand in 1a and 1b has been displaced from its co-ordination to cobalt. The reactions of 2a and 2b with organophosphites and isocyanides lead to monosubstituted products.