Reactions of 2-arsa- and 2-stiba-1,3-dionato lithium complexes with group 4–7 metal halides

Abstract

The reactions of a range of 2-arsa- and 2-stiba-1,3-dionato lithium complexes with group 4–7 metals have been investigated. These have given rise to several complexes in which an arsadionate acts as a chelating ligand; [V{η 2-O,O-OC(Bu t )AsC(Bu t )O} 3], [M{η 2-O,O-OC(Bu t )AsC(Bu t )O} 2(DME)], M=Cr or Mn; or as an η 1-As-diacylarsenide, [MnBr(CO) 4{As[C(O)Bu t ] 2Li(DME)}] 2. In addition, reactions of lithium arsadionates with TaCl 5 have led to metal mediated arsadionate decomposition reactions and arsadionate oxidative coupling reactions to give the known arsaalkyne tetramer, As 4C 4Bu t 4, and the new tetraacyldiarsane, [{As[C(O)Mes] 2} 2] Mes=mesityl, respectively. The treatment of several lithium arsadionates with [MoBr 2(CO) 2(PPh 3) 2] has also initiated arsadionate decomposition reactions and the formation of the metal carboxylate complexes, [MoBr(CO) 2{η 2-O 2C(R)}(PPh 3) 2] R=Bu t , Ph, Mes. The X-ray crystal structures of six of the prepared complexes are discussed.