Structural studies of phosphor-1,1-diselenoato Mn(I) and Re(I) complexes

Mononuclear complexes of the type, M(CO)(4)[Se2P(OR)(2)] (M = Mn, R = Pr-i, 1a; Et, 1b; M = Re, R = Pr-i, 3a; Et, 3b) can be prepared from either [-Se(Se)P((OPr)-Pr-i)(2)](2) (A) or [Se{-Se(Se) P(OEt)(2)}(2)] (B) with M(CO)(5)Br. O,O'-dialkyl diselenophosphate ([RO)(2) PSe2](-), abbreviated as dsep) ligands generated from A and B act as a chelating ligand in these complexes. Upon refluxing in acetonitrile, these mononuclear complexes yield dinuclear complexes with a general formula of [M-2(CO)(6){Se2P(OR)(2)}(2)] (M = Mn, R = Pr-i, 2a; Et, 2b; M = Re, R = Pr-i, 4a; Et, 4b). Dsep ligands display a triconnective, bimetallic bonding mode in the dinuclear compounds and this kind of connective pattern has never been identified in any phosphor-1,1-diselenoato metal complexes. Compounds 2b, 3b, and 4 are structurally characterized. Compounds 2b and 3b display weak, secondary Se center dot center dot center dot Se interactions in their lattices. (C) 2008 Elsevier B.V. All rights reserved.