Ring expansion of a Cp moiety upon CO insertion: Synthesis and characterization of [(η 6-C 6H 5OCo)Co 3(CO) 9

Abstract

Reaction of [(CpV) 2(B 2H 6) 2], 1 (Cp = η 5-C 5H 5) with four equivalents of [Co 2(CO) 8] or [Co 4(CO) 12] in hexane at 70 °C leads to the isolation of the tetranuclear carbonyl cluster, [(η 6-C 6H 5OCo)Co 3(CO) 9], 2 in modest yield. The geometry of 2 is similar to that of [Co 4(CO) 12] where all the four Co atoms are arranged in a tetrahedral geometry. The apical cobalt atom in 2 is coordinated to C 6H 5O ring in a η 6-fashion and the other three cobalt atoms are each coordinated to three carbonyl ligands. Compound 2 has been characterized in solution by IR, 1H, 13C NMR and mass spectrometry and the structural types were unequivocally established by crystallographic analysis.