Stabilisation of vinylic intermediate in the addition, cylisation, and oligomerisation reactions of alkynes by co-ordination to molybdenum and tungsten. The crystal and molecular structure of [W(SC6H4Me-p){η2-C(CF3)·C(CF3)PEt3}(η2-CF3C
CCF3)(η-C5H5)] and [WCl{η2-C(CF3)·C(CF3)CNBut}(η2-CF3C
CCF3)(η-C5H5)]
Abstract
Nucleophilic atteck of phosphines, phosphites, and t-butyl isocyanide (L) on the bis-hexafluorobut-2-yne complexes [WBr2CO(CF3CCCF3)2] and [MX(CF3C
CCF3)2(η-C5H5)](M = Mo, W; X = Cl, SC6F5: M = W; X = SC6H6Me-p) occurs at an acetylenic carbon atom to give 1:1 adducts shown by X-ray deffraction studies to contain a metal-stabilised 1–3 dipolar vinyl ligand LC(CF3)·C(CF3) co-ordinated in an η2 manner to the metal centre.