Generation and Trapping of a Superelectrophilic Terminal Fluorophosphinidene Complex
摘要:
Comparative DFT calculations on terminal phosphinidene complexes [MeP-Cr(CO)(5)] and [FP-Cr(CO)(5)] show a huge increase of the positive charge at P when replacing the methyl by the fluorine substituent (NBO charges +0.60 and +0.94). The electrophilic fluorination of the (3,4-dimethylphospholyl)pentacarbonylmolybdenum anion by Selectfluor gives a straightforward access to the corresponding 1-fluoro-3,4dimethylphosphole molybdenum complex. This complex reacts as a conjugated diene with dimethyl acetylenedicarboxylate to give the corresponding 7-fluoro-7-phosphanorbornadiene complex. This bicyclic species is a precursor of [FP-Mo(CO)(5)] at 120 degrees C in xylene, as shown by trapping reactions with diphenylacetylene and 2,3-dimethylbutadiene.