Synthesis, characterization and decomposition patterns for thienylene bridged dinuclear biscarbene complexes of manganese and chromium in refluxing carbon disulphide and acetone

The dinuclear complexes [ML3(CO)(2){C(OEt)C4H2SC(OEt)}M(CO)(2)L-3] (M = Cr, L = CO 1; M = Mn, L-3 = eta(5)-C5H4R, R = H 2 and Me 3) were synthesized from dilithiated thiophene according to the Fischer-method. The highly reactive biscarbene complexes are unstable in acetone and react to afford [ML3(CO)(2){C(OEt)C4H2SC(O)OEt] (M = Cr 4, M = Mn, R = H 5 and Me 6). When refluxed in carbon disulphide, 1 affords as the only isolable product 4, whereas 2 and 3, in addition to 5 and 6, reacts with CS2 to give the thiono ester compounds [Mn(eta(5)-C5H4R)(CO)(2){C(OEt)C4H2SC(S)OEt}] with R = H 7 and Me 8, respectively. Compound 1 crystallizes in the monoclinic space group C2/c with a = 21.593(12), b = 10.235(3), c = 22.531(12) Angstrom, beta = 92.06(4)degrees and Z = 8. (C) 1998 Elsevier Science S.A. All rights reserved.