Mo 2Cp Research Articles

Trifluoromethylisocyanide CF 3NC, a very strong π-accepting ligand in metal organic chemistry

Isocyanides, RNC, are isoelectronic to carbon monoxide. A lot of transition metal complexes containing these ligands have been published during the last century. But till now no perfluorinated isocyanide has been used as a ligand. Due to the strong electron withdrawing effect of the trifluoromethyl-group one can expect an enhancement of the π-accepting ability of trifluoromethylisocyanide. Preparation and structural investigation of the new complexes (CO) 5Cr(CNCF 3), (CO) 5W(CNCF 3) and Ni(CNCF 3) 4 allow the conclusion that CF 3NC as a ligand behaves more like carbon monoxide than like a common isocyanide. In addition trifluoromethylisocyanide bridged complexes like Ni 2Cp 2(CNCF 3) 2, Mo 2Cp 2(CO) 4(CNCF 3) 2 and Fe 3(CO) 11(CNCF 3) have been prepared.