η2-Sulfenamido and -selenamido complexes of titanium, zirconium, molybdenum and tungsten

Abstract

The interaction of TiCl₄ with LiN(Bu^t)SR (R = Ph or C₆H₂Me₃-2,4,6) gave the sulfenamido complexes TiCl₂(η²-Bu^tNSR)₂. Interaction of ZrCl₄ with 3 equivalents of LiN(Bu^t)SPh produced ZrCl(η²-Bu^tNSPh)₃ while ZrCl₄(tht)₂(tht = tetrahydrothiophene) with 5 equivalents gave the homoleptic Zr(η²-Bu^tNSPh)₄. From ZrCl₂(η⁵-C₅H₅)₂ only ZrCl(η⁵-C₅H₅)₂(η²-Bu^tNSPh)5 is obtained. Using as starting materials MO₂Cl₂(dme)(dme = 1,2-dimethoxyethane, M = Mo or W), MoCl₂(NBu^t)₂ and WCl₂(NBu^t)₂(py)₂(py = pyridine), interactions with LiNBu^tSPh gave η²-sulfenamido compounds such as MoO₂(η²-Bu^tNSPh)₂. The selenium analogue of the tungsten compound, i.e. W(NBu^t)₂(η²-Bu^tNSePh)₂ has been made by interaction of Li₂W(NBu^t)₄ with PhSeBr. Where study was possible, NMR spectra over a temperature range indicate that invertomers and isomers occur. Six compounds have been structurally characterised by X-ray diffraction. In all cases the sulfenamido ligands are η² bonded and the geometry about the N atoms is planar.