Hydrazido(2–)-complexes of tungsten-(<scp>V</scp>) and -(<scp>VI</scp>) and a bis(diazenido)-complex of tungsten(<scp>IV</scp>). X-Ray crystal structure of cis-[WCl₃(NNH₂)(PMe₂Ph)₂]

Abstract

The hydrazido(2–)–hydride complexes [WX2H(NNH2)(PMe2Ph)3]X (1; X = Cl or Br), [WCI3H(NNH2)(PMe2Ph)2](2), and [WCl3H(NNHPh)(PR3)2](3)(PR3= PMe2Ph, PMePh2, or PPh3) have been prepared by treatment of [WX2(NNH2)(PMe2Ph)3] with HX in tetrahydrofuran and of [WCl4(PR3)2] with PhNHNH(SiMe3) respectively. The complexes (1; X = Cl) and (3; PR3= PMe2Ph) convert into the hydrazido(2-) complexes cis-[WCl3(NNH2)(PMe2Ph)2](4) and trans-[WCl3(NNHPh)(PMe2Ph)2](5) respectively on slow recrystallisation. The X-ray structure of (4)(space group Pnma, R= 0.055) in which the N-H atoms have been located, shows the hydrazido(2-) ligand to have a planar N–NH2 group [d(WN)= 1.752(10), d(NN)= 1.300(17), d(NH)= 1.08 and 0.78 Å; N–N–W = 178.7(9)°]. The preparation of the complexes [WCL4L2](L = pyridine, 2-, 3-, or 4-methylpyridine, or quinoline) from [WCl4(PPh3)2] is also described. [WCl4(C5H5N)2] reacts with PhNHNH-(SiMe3) to give the bis(diazenido)-complex [WCl2(NNPh)2(C5H5N)2](6). Spectroscopic data for all new complexes are discussed in terms of their structures.