Syntheses of diiridium complexes with two bridging tetrachalco-genide ligands [{Ir(#eta#~5-C_5Me_5)}_2(#mu#-E_4)_2] (E = Se or S) and their reactions with alkynes forming mono- or di-nuclear dichalcogenolene complexes

摘要

Treatment of [ClCpIr(#mu#-Cl)_2IrCpCl] 1 (Cp = #eta#~5-C_5Me_5) with 2 equivalents of Li_2Se_4 in THF at 50 deg C afforded a diiridium complex with two bridging tetraselenide ligands [CpIr(#mu#-Se_4)_2IrCp] 2. The sulfur analog [CpIr(#mu#-S_4)_2IrCp] 3 was also obtained by either the reaction of 1 with Li_2S_4 or treatment of a mixture of [ClCpIr(#mu#-SH)_2IrCpCl] and S_8 with Net_3. When treated with MeO_2CC (ident to) CCO_2Me (DMAD), 2 afforded the diselenolene complexes [CpIr(#mu#-Se_4){#mu#-Se_2C_2(CO_2Me)_2}IrCp] and [IrCp{Se_2C_2(CO_2Me)_2}] as well as the DMAD adduct to the latter [IrCp{Se_2C_4(CO_2Me)_4}]. Analogous treatment of 2 with HC (ident to) CCO_2Me (MAMC) resulted in formation of diiridium complexes with bridging diselenolene ligand(s) [CpIr(#mu#-Se_4){#mu#-Se_2C_2H(CO_2Me)}IrCp] and [CpIr{#mu#-Se_2C_2H(CO_2Me)}_2IrCp] but no complex corresponding to [IrCp{Se_2C_4(CO_2Me)_4}]. Reactions of 3 with these alkynes were also carried out for comarison, which led to exclusive formation of the mononuclear complexes: [IrCp{S_2C_2(CO_2Me)_2}] and [IrCp{S_2C_4(CO_2Me)_4}] for DMAD and [IrCp{S_2C_2H(CO_2Me)}] for MAMC, respectively. X-Ray analyses were undertaken to clarify the detailed structures of seven complexes.