Synthesis, characterization, and reactivity of manganese(II) and iron(II) trifluoroacetates. Crystal and molecular structure of two linkage isomers of polynuclear [Mn(CF3COO)2(THF)2]n

Abstract

The trifluoroacetates of manganese(II) and iron(II) have been prepared as THF or DMF adducts by reaction of metallic manganese or pentacarbonyliron(0) in THF or DMF, respectively, with CF3COOH–(CF3CO)2O. Crystals of two linkage isomers of polynuclear [Mn(CF3COO)2(THF)2]n have been obtained differing in the distribution of the bridging trifluoroacetato groups within the repeating units, namely [(THF)2Mn(µ-CF3COO)3Mn(THF)2(µ-CF3COO)] and [(THF)2Mn(µ-CF3COO)2Mn(µ-CF3COO)2(THF)2]. Photolysis of Fe(CO)5 in CF3COOH–(CF3CO)2O mixtures or in neat (CF3CO)2O gives the trifluoroacetato of iron(II) Fe(CF3COO)2, whose formation may occur through the intermediacy of Fe2(CO)9.Key words: linkage isomers, manganese, iron, carboxylates, X-ray structure.