Reactions of metal carbonyl derivatives. Part 20. Synthesis, redox behaviour, and crystal and molecular structure of µ-ethylthio-bis-[dicarbonyl(η-methylcyclopentadienyl)manganese](Mn–Mn) perchlorate: an unusual monothio-bridged derivative of manganese

Abstract

Treatment of [Mn(MeC₅H₄)(CO)₂(SEt)]^–, prepared in situ from [Mn(MeC₅H₄)(CO)₂(thf)] and [SEt]^–, with perchloric acid in aqueous tetrahydrofuran leads to the formation of the unusual monothio-bridged derivative [{Mn(MeC₅H₄)(CO)₂}₂(SEt)][ClO₄], in which the manganese atoms are joined by a metal–metal bond (MeC₅H₄=η-methylcyclopentadienyl). A crystal structure determination by the heavy-atom method from diffractometer data of this complex reveals the cyclopentadienyl groups to be trans, and Mn–Mn 2.930(1)Å. Crystals are monoclinic, space group P2₁/n, Z= 4, a= 8.676(5), b= 16.062(5), c= 15.872(5)Å, β= 104.45(20)°, and the structure was refined to R 0.51 for 1 785 observed reflections. The compound undergoes two reversible one-electron reductions as established by cyclic voltammetry and polarography.