Synthesis and characterization of diphenyl-2-thienylphosphine derivatives of di- and tricobalt carbonyl complexes

The reaction of [Co-2{mu-C-2(CO2Me)(2)}(CO)(6)] with the ligand diphenyl-2- thienylphosphine, PPh2(C4H3S), yields the complexes [Co-2{mu-C-2(CO2Me)(2)} (CO)(5) {PPh2(C4H3S)}] (1) and [Co-2{mu-C-2(CO2Me)(2)}(CO)(4){PPh2(C4H3S)(2 )}] (2). The related complex [Co-3(mu(3)CMe)(CO)(9)] reacts with the same l igand to give [Co-3(mu(3)-CMe)(CO)(8){PPh2(C4H3S)}] (3) and [Co-3(mu(3)-CMe )(CO)(7) {PPh2(C4H3S)}(2)] (4). Thermolysis of 1 at 80 degrees C leads to p artial conversion of 1 into 2, which is isolated in low yield. Similarly, t hermolysis of 3 at 70 degrees C results in partial conversion of 3 to 4. Co ordination of the thienyl unit of the diphenyl-2-thienylphosphine ligand to cobalt could not be detected in these thermolyses. Complexes 1-4 have been completely characterized and the crystal structure of complex 4 has been d etermined. (C) 1999 Elsevier Science S.A. All rights reserved.