Unusual thiophene complexes from reactions of Cp*Ir(2,5-dimethylthiophene) with sources of W(CO)5, Cr(CO)4, MO(CO)4, and Fe(CO)3

The isomers, Cp*Ir(eta(4)-2,5-Me2T) (1) and Cp*Ir(C,S-2,5-Me2T) (2), where 2,5-Me2T is 2,5-dimethylthiophene, are observed to coordinate to metal carbonyl fragments in various ways when reacted with metal complexes W(CO)(5)(THF), Cr(CO)(4)(COD), Mo(CO)(4)(NBD) and Fe(CO)(3)(BDA), that contain readily displaceable ligands (COD = 1,5-cyclooctadiene, NBD = norbornadiene, BDA = benzylidene acetone). In Cp*Ir(eta(4)-2,5-Me2T.M(CO)(5)), the M(CO)(5) unit (M = Cr, Mo, or W) is coordinated to the sulfur atom of 1. The iridathiabenzene ring of 2 coordinates to a M(CO)(3) moiety through all six atoms in [eta(6)-Cp*Ir(C,S-2,5-Me2T)]M(CO)(3), where M = Cr or Mo. The iridathiabenzene ring in the CO adduct of 2, Cp*Ir(C,S-2,5-Me2T)(CO), coordinates through the sulfur to W(CO); in 6, Cp*Ir[C,S-2,5-Me2T.W(CO)(5)](CO), and through five atoms (not the Ir) to Cr(CO)(3) in 14, Cp*Ir(C,S-2,5-Me2T.Cr(CO)(5))(CO). Structures of 6 and 14 are reported. (C) 2002 Elsevier Science B.V. All rights reserved.