Preparation and characterisation of mononuclear organoimido complexes of tungsten: X-ray crystal structures of [WCl4(NC6H4Me-p)(thf)], [P(CH2Ph)Ph3][WCl5(NC6H4Me-p)], and [WCl2(NPh)2(bipy)

Abstract

Some mononuclear organoimido complexes of WVI and WV have been prepared and the X-ray structures of [WCl4(NC6H4Me-p)(thf)](thf = tetrahydrofuran)(1) and [P(CH2Ph) Ph3][WCl5(NC6H4Me-p)](2) determined. In both species the octahedral WVI centre is strongly bound to the tolylimido group [W[graphic omitted]N 1.711(7) for (1) and 1.709(11)A for (2)] causing a bending down of the four equatorial W–Cl bonds [W–Cl 2.313(4)–2.349(6)A] and a lengthening of the trans bond [W–O 2.237(6), W–Cl 2.464(5)A]. The 14N and 15N n.m.r. spectra of the ethylimido compounds [WCl4(NEt)(thf)] and [P(CH2Ph)Ph3][WCl5(NEt)], and the t-butylimido compound [W(NBut)2(NHBut)2] have been obtained. From reactions of the binuclear bis(organoimido) complexes [{WCl2(NR)(NR′)(NH2R′)}2] with neutral ligands [PMe3 or 2,2′-bipyridyl (bipy)] the mononuclear bis(organoimido) complexes [WCl2(NR)(NR′)(PMe3)2] and [WCl2(NR)(NR′)(bipy)] were obtained. The X-ray crystal structure of [WCl2(NPh)2(bipy)] has been determined and the distorted octahedral structure comprises cis-phenylimido groups and trans-dichloro ligands with the bipy nitrogens trans to the imido nitrogens. The phenylimido ligands are equivalent with mean W[graphic omitted]N bond lengths of 1.775(14) and 1.782(14)A and mean W–N–C angles of 165.3(12) and 166.3(12)°.