Nucleophilic addition and substitution reactions on the sulfur atoms bound to two Ir atoms. Conversion of a hydrosulfido complex [(#eta#~5-C_5Me_5)_2Ir_2(#su#-SH)_3]Cl into a series of diiridium complexes with bridging tiolato ligands

摘要

The hydrosulfido-bridged diiridium complex [CpIr(#mu#-SH)_3IrCp]Cl 2 (Cp = #eta#-C_5Me_5) reacted with an excess of CH_2=CHX (X = COMe, SO_2Ph, COOMe, CN) in the presence of NEt_3 (4 equiv) in MeCN to afford the diiridium complexes [CpIr(#mu#-SCH_2CH_2X)_3IrCp]Cl 4, which contain three bridging thiolato ligands derived from the Michael addition of the #mu#-SH ligands in 2 to the activated alkenes. In contrast, when only 2 equiv of CH_2=CHX (X = SO_2Ph, CN) were allowed to react with 2 under analogous conditions, ulfido-thiolato complexes [CpIr(#mu#-S)(#mu#-SCH_2CH_2X)_2IrCp] 5 were obtained exclusively. Reaction of 5d (X = CN) with neat ClCH_2CH_2Cl and that of 2 with CH_2=CHCN in ClCH_2CH_2Cl in the presence of NEt_3 both gave a mixed-thiolato complex [CpIr(#mu#-SCH_2CH_2Cl)(#mu#-SCH_2CH_2CN)_2IrCp]Cl 6. Diiridium complexes with bridging dithiolato ligands were also obtainable from 2, which include [CpIr(#mu#-SCH_2CH_2S)(#mu#-SCH_2CH_2Cl)IrCp]Cl 7 from the reaction with ClCH_2CH_2Cl/NEt_3 along with [CpIr{#mu#-SCH_2CH_2CH(OH)S}(#mu#-SCH_2CH_2CHO)IrCp]Cl and [CpIr{#mu#-SCHPhCH_2CH(OH)S}(#mu#-S)IrCp] 9 afforded by treatment with #alpha#,#beta#-unsaturated aldehydes CH_2=CHCHO and PhCH=CHCHO, respectively Reaction of 2 with ethylene sulfide in the presence of NEt_3 also yielded a diiridium complex with bridging dithiolato ligand [CpIr(#mu#-SCH_2CH_2S)_2IrCp] 10. Detailed structures have been determined by X-ray analyses for 4b (X = SO_2Ph), 5d 9, and 10, as well as the PF_6 salts of 6 and 7.