Facile synthesis of “WCl3(DME)” and structural and electronic characterizations

Abstract

AbstractIn contrast to the readily accessed mid‐valent molybdenum precursors, trivalent tungsten compounds as good synthons are rare. The most commonly used trivalent ditungsten species, NaW2Cl7(THF)5, for the synthesis of the triply W − W bonded compounds of the type W2X6(X = bulky anionic ligand) can no longer be prepared because it is obtained from Na/Hg reduction of WCl4, and the use of mercury is banned. In this work, we report the characterization of a useful ditungsten(III) complex W2(μ‐Cl)2Cl4(κ2‐DME)2(2) (DME = 1,2‐dimethoxyethane) to replace NaW2Cl7(THF)5. The efficient reduction of the monomeric W(IV) compound WCl4(DME) (1) with granular Sn in DME gives2in a 97% isolated yield.2is a diamagnetic species based on SQUID magnetometry, and its formulation was established by single‐crystal X‐ray crystallography. The structure of2shows an edge‐sharing bioctahedral (ESBO) conformation with overallCisymmetry and the W − W bond length is 2.6443 (6) Å. Density functional theory (DFT) calculations suggest a σ2π2δ*2ground state configuration corresponding to the W − W single bond.