Fischer-type alkylidyne tungsten complexes containing strong π donor ligands

Abstract

Reaction of [W(CPh)Cl(CO)(PMe 3) 3] ( 1), with NaNC 4H 4, NaNC 8H 6, NaOC 6H 5 and NaSR (R = CMe 3, C 6H 11) in THF afford the alkylidyne tungsten complexes [W(CPh)X(CO)(PMe 3) 3] ( 2a−e), containing pyrrolide, indolide, phenoxide and alkylsulfide ligands, X, respectively. The π donor ligands X occupy the coordination site trans to the alkylidyne ligand. The anionic complexes [NEt 4][W(CPh)X 2(CO)(PMe 3) 2] ( ( 3a) X = NC 4 H 4), (( 3a) X = NC 8 H 6 ), form upon reaction of 1 with 2 equiv. of NaNC 4H 4 and NaNC 8H 6 in THF, followed by metathesis with NEt 4Cl in CH 2Cl 2. Reaction of 1 with the sodium salt of pyrrole-2-carboxaldehydemethylimine affords [W(CPh(NC 4H 3-CHNMe-2)(CO)(PMe 3) 2] ( 4). The solid state structures of complexes 2a and 2e were determined by X-ray crystallography. Complex 2d reacts in THF solution with carbon monoxide to afford cis-[W(CPh)(SCMe 3)(CO) 2(PMe 3) 2] ( 6). In contrast, the analogous bromo complexes [W(CPh)Br(CO)(PMe 3) 3] ( 7) gives under the same conditions an equilibrium mixture of 7 and trans-[W(CPh)Br(CO) 2(PMe 3) 2].