Dithiocarbamate derivatives of μ-thiocarbyne complexes:: synthesis and X-ray molecular structure of [Fe2(μ-CS)(μ-CSMe)(μ-S2CNMe2)CP2]

Reaction of [Fe-2(mu-CS)(mu-CSMe)CP2(CO)(2)](+) (1) with sodium N,N-dimethyldithiocarbamate [Me(2)dtc]Na affords a mixture of the dithiocarbene [FeFe(mu-CS) {mu-C(SMe)SC(S)NMe2}CP(CO)] (2) and the thiocarbyne [Fe-2(mu-CS)(mu-CSMe)(mu-S2CNMe2)CP2] (3). Complex 2 is quantitatively converted into 3 by photochemical irradiation. The X-ray molecular structure of 3 demonstrates the presence of three bridging ligands and exhibits the shortest Fe-Fe interaction found in similar systems [2.453(1)Angstrom]. Complex 3 can also be obtained by reacting [Me(2)dtc](-) with the di-solvento thiocarbyne [Fe-2(mu-CS)(mu-CSMe)(NCMe)(2)CP2](+) (1a). By contrast no stable addition product has been isolated in analogous reactions involving the thiocarbyne [Fe-2(mu-CO)(mu-CSMe)Cp-2(CO)(2)](+)(1b). The [Me(2)dtc](-) nucleophilic addition at the mu-C to form [Fe-2(mu-CO){mu-C(CN)SC(S)NMe2}Cp-2(CO)(2)] (4a) is obtained starting from [Fe-2(mu-CO){mu-C(CN)(SMe2)}Cp-2(CO)(2)]SO3CF3 (1d). Photochemical reaction of the cyanocarbene 4a causes intramolecular ring closure affording [FeFe(mu-CO){mu-C(CN)SC(S)NMe2}Cp-2(CO)] (5a). (C) 2002 Elsevier Science B.V. All rights reserved.