Interconversions of simple monodentate nitrogen donor ligands bound to Tp′ tungsten fragments

The dramatic effect of an ancillary alkyne ligand on the regioselectivity of nucleophile and electrophile additions to monodentate nitrogen ligands is illustrated by comparison of ligand based reactions characteristic of nitrogen donor ligands incorporated into [Tp'(CO)(2)W](+) and [Tp'(CO)(PhCCMe)W](+) coordination spheres. Nitrogen ligands accessible from free nitriles and amines, including nitrile, azavinylidene, imido, imine, amido, amine, and nitrido, can be interconverted by addition of nucleophiles or electrophiles as well as by hydride abstraction or proton removal. Structural details that reveal important pi-bonding interactions for multiply bonded nitrogen ligands are also discussed. (C) 2003 Elsevier Ltd. All rights reserved.