Intramolecular C-N bond activation by a transient boryl anion.

Using a flexible diamido framework, a bulky boron bromide has been prepared as a precusor to a boryl anion with an extremely wide N-B-N angle. Reduction of the compound with lithium metal resulted in intramolecular C-N bond activation and migration of an aryl group onto the boron centre. Reaction of the boron bromide with K[FeCp(CO)] resulted in nucleophilic reactivity of a carbonyl oxygen and the cooperative activation of CO.

Heterobimetallic μ-halocarbyne complexes.

The halocarbyne complexes [M(CX)(CO)(Tp*)] (M = Mo, W; X = Cl, Br; Tp* = hydrotris(dimethylpyrazolyl)borate) react with [AuCl(SMe)], [Pt(η-HCCH)(PPh)] or [Pt(η-nbe)] (nbe = norbornene) to furnish rare examples of μ-halocarbyne complexes [MAu(μ-CX)Cl(CO)(Tp*)], [MPt(μ-CCl)(CO)(PPh)(Tp*)] and [WPt(μ-CCl)(CO)(Tp*)]. The complex [WPt(μ-CCl)(CO)(PPh)(Tp*)] spontaneously rearranges to the μ-carbido complex [WPt(μ-C)Cl(CO)(PPh)(Tp*)] during silica-gel chromatography. One phosphine ligand of [WPt(μ-CCl)(CO)(PPh)(Tp*)] is readily substituted by CO to afford [WPt(μ-CCl)(CO)(PPh)(Tp*)].