Challenging an old paradigm by demonstrating transition metal-like chemistry at a neutral nonmetal center
David Biskup, Gregor Schnakenburg, Renè T. Boeré, Arturo Espinosa Ferao, Rainer Streubel
Abstract
Abstract We describe nonmetal adducts of the phosphorus center of terminal phosphinidene complexes using classical C- and N-ligands from metal coordination chemistry. The nature of the L-P bond has been analyzed by various theoretical methods including a refined method on the variation of the Laplacian of electron density ∇ 2 ρ along the L-P bond path. Studies on thermal stability reveal stark differences between N-ligands such as N -methyl imidazole and C-ligands such as tert -butyl isocyanide, including ligand exchange reactions and a surprising formation of white phosphorus. A milestone is the transformation of a nonmetal-bound isocyanide into phosphaguanidine or an acyclic bisaminocarbene bound to phosphorus; the latter is analogous to the chemistry of transition metal-bound isocyanides, and the former reveals the differences. This example has been studied via cutting-edge DFT calculations leading to two pathways differently favored depending on variations in steric demand. This study reveals the emergence of organometallic from coordination chemistry of a neutral nonmetal center.