Regiospecific Reaction between Dimetallic Phosphido-Bridged W-W Complexes and Phosphane Imide - Electrophilic Site Switching by Metal-Metal Bond Formation

摘要

Reaction between CpW(CO)_2(#mu#-PPh_2)W/CO)_4-(CNR)(W-W) (4). Spectroscopic data indicate that the complex exists in two stereoisomeric forms in solution. The structure of the cis isomer was determined by a single-crystal X-ray diffraction study which indicates that the CNR ligand is coordinated to the W atom of the W(CO)_4 unit and cis to the phosphido bridge. Reaction between CpW(CO)_3(#mu#-PPh_2)W(CO)_5 (1) and Ph_3P=NR (R = Pr, CH_2Ph, iPr) in THF under simillar condition is also regiosepecific. However, the CNR ligand is coordinated to the CpW site to produce CpW(CO)_2(CNR)(#mu#-PPh_2)W(CO)_5 (3). There are also two stereoisomers of the complex, which were separated by column chromatography. Structures of both isomers were determined by single-crystal X-ray diffraction studies.