A Self‐Assembling Ligand Switch That Involves Hydroxide Addition to an sp² Hybridised Phosphorus Atom – A System Allowing OH^– Mediated Uptake of [MCl₂] (M = Pd, Pt) Centres

Abstract

The coordination chemistry of the 1,1′-diphosphacobaltocenium salt [Co(η 5 -2-TBS-3,4-Me 2 -PC 4 H) 2 ] + BF 4 -(rac-1) and its derivatives with respect to [MCl 2 ] (M = Pd, Pt) centres is presented. Rac-1, showing two sp 2 hybridised phosphorus atoms and a positive charge, is stable towards strong electrophiles (PhCH 2 Br, MeI), but undergoes attack by hydroxide at phosphorus with subsequent rearrangement to form the neutral conjugate base [Co{η 5 -(2-TBS-3,4-Me 2 -PC 4 H)}{η 4 -(1-O,1-H-2-TBS-3,4-Me 2 -PC 4 H)}] (rac-2). Rac-1 undergoes reaction with [MCl 2 (PhCN) 2 ] (M=Pd, Pt) in damp chloroform to form the P sp2 -P sp3 chelating sec-phosphinite complexes [MCl 2 {Co{η 5 -(2-TBS-[a]