Tris(phosphaalkyne)tungsten Complexes

We report on the reactivity of a boryloxy-functionalized phosphaalkyne, [B]­OCP ([B] = N,N′-bis­(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaboryl), toward a series of tungsten(0) reagents to afford the novel complex W­(η2-PCO­[B])3(CO). As with related organometallic complexes of alkynes, the C3v symmetry adopted by this complex imposes that, of the three coordinated phosphaalkyne ligands, two act as four-electron donors while the remaining species donates two electrons to the tungsten metal center. W­(η2-PCO­[B])3(CO) readily loses carbon monoxide in the presence of Lewis bases to afford W­(η2-PCO­[B])3(L) (where L = PMe3, CNtBu).