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

Abstract The dinuclear complexes [ML 3 (CO) 2 {C(OEt)C 4 H 2 SC(OEt)}M(CO) 2 L 3 ] (M=Cr, L=CO 1 ; M=Mn, L 3 = η 5 -C 5 H 4 R, 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 [ML 3 (CO) 2 {C(OEt)C 4 H 2 SC(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 CS 2 to give the thiono ester compounds [Mn( η 5 -C 5 H 4 R)(CO) 2 {C(OEt)C 4 H 2 SC(S)OEt}] with R=H 7 and Me 8 , respectively. Compound 1 crystallizes in the monoclinic space group C 2/c with a =21.593(12), b =10.235(3), c =22.531(12) A, β =92.06(4)° and Z =8.