Reaction of CS₂ with a ligand-bridged dicobalt complex: Crystal and molecular structures of [Co₂{μ-PPh₂CHC(SiMe₃)C(O)CS}(μ-PPh ₂S) (CO)₃] and [Co₂(μ-PPh₂CHCPhCS)(μ-PPh₂S)(CO) ₃]

Thermolysis of [Co₂{μ-PPh₂CHCRC(O)}(μ-PPh₂)(CO) ₄] (R = SiMe₃ 1a or Ph 1b) in CS₂ affords the complexes [Co₂{μ-PPh₂CHCRC(O)CS}(μ-PPh₂S)(CO) ₃] (R = SiMe₃ 2a 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.