Generating Phosphinidene−N-Methylimidazole Adducts under Mild Conditions
摘要:
The nucleophilic attack of N-methylimidazole at the bridge phosphorus of a 7-phosphanorbornadiene pentacarbonylmolybdenum complex induces the collapse of the bridge. According to DFT calculations, the resulting zwitterion displays a very long and weak P-Mo bond. The excess of N-methylimidazole thus appears to be able to displace the phosphinidene from its molybdenum complex. The final result is a phosphinidene-N-methylimidazole adduct whose structure has also been computed. When applied to the phenyl derivative at 40 C in toluene, this reaction effectively generates the [PhP] adduct, which decomposes to give essentially Ph4P4 and Ph5P5. At 80 degrees C, PhPH2 is also produced. In the presence of CCl4 the phosphinidene adduct inserts into the C-Cl bond to give PhP(Cl) CCl3.