REDUCTION OF A COORDINATED ACETONITRILE LIGAND - SYNTHESIS OF AN ETHYLIMIDO COMPLEX OF TUNGSTEN

Treatment of the dinitrogen complex W(N-2)(2)(dppe)(2) (1; dppe = 1,2- bis(diphenylphosphino)ethane) with trifluoromethanesulfonic acid yield s the novel hydrazido complex [W(N2H2)(oTf)(dppe)(2)](+)[oTf](-) (2; O Tf = CF3SO3-). The triflato ligand is readily displaced by other ligan ds and coordinating solvents. The triflato complex 2 yields the comple x [W(N2H2)(NCCH3)(dppe)(2)](2+) (5), when it is dissolved in acetonitr ile, and 5 is readily deprotonated by a variety of bases to give the a cetonitrile-dinitrogen complex W(N-2)(NCCH3)(dppe)(2) (3). Complex 3 i s protonated at the beta-carbon by tetrafluoroboric acid, resulting in the reduction of the coordinated nitrile to give the novel imido comp lex [WF(NCH2CH3)(dppe)(2)](+)[BF4](-)(4). The X-ray crystal structure of the imido complex 4 reveals an effectively linear W-N-C bond (171.8 degrees) in the imido ligand with a W-N bond length of 1.741(4) Angst rom.