Iron(0) and Ruthenium(0) Complexes of Dinitrogen

The synthesis of a series of iron and ruthenium complexes with the new ligand PPi3 (1) P(CH2CH2PiPr2)3 is described. The iron(0) and ruthenium(0) dinitrogen complexes Fe(N2)(PPi3) (4) and Ru(N2)(PPi3) (5) were synthesized by treatment of the iron(II) and ruthenium(II) cationic species [FeCl(PPi3)]+ (2) and [RuCl(PPi3)]+ (3) with potassium graphite under a nitrogen atmosphere. The cationic dinitrogen species [Fe(N2)H(PPi3)]+ (6) and [Ru(N2)H(PPi3)]+ (7) were prepared by treatment of 4 and 5, respectively, with 1 equiv of a weak organic acid. Complexes 2·[BPh4], 3·[BPh4], 4, 5, and 6·[BF4] were characterized by X-ray crystallography. The structural characterization of 5 is the first report for a ruthenium(0) dinitrogen complex.