Novel cleavage product of the reaction of a ditertiary arsine with decacarbonyldimanganese: crystal structure of µ-(dimethylarsino)-µ-{1–3-η-[2,3-bis(dimethylarsino)-1,1-difluoro-3-trifluoromethylallyl]-(As, As′, C, C′, C″)}bis[tricarbonylmanganese(I)]

Abstract

Crystals of the title compound are triclinic with a= 9·580. b= 15·279, c= 9·292 Å, Z= 2, space group P. The structure was solved by the heavy-atom method from diffractometer data and refined by least-squares methods to R 7·8%(2233 observed reflections). Each manganese atom has an irregular octahedral environment which includes three fac-carbonyl groups. The two manganese atoms are linked by a bridging dimethylarsino-group. A further link between the two manganese atoms is provided by the substituted π-allyl ligand, F₂C C(AsMe₂)(CF₃)CAsMe₂. Both arsenic atoms bond to Mn(1) while the C₃-allyl system bonds symmetrically to Mn(2). Some distances are: Mn(2)–C(terminal allyl) 2·09(2) and 2·13(2), Mn(1)–As(1) 2·455(4), Mn(2)–As(1) 2·507(4), Mn(1)–As(2) 2·354(4), and Mn(1)–As(3) 2·387(4)Å. The configuration of the π-allyl ligand and significant differences in Mn–As bond lengths are discussed.