Metal‐Mediated Oligomerization Reactions of the Cyaphide Anion

Abstract

The cyaphide anion, CP−, is shown to undergo three distinct oligomerization reactions in the coordination sphere of metals. Reductive coupling of Au(IDipp)(CP) (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) by Sm(Cp*)2(OEt2) (Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl), was found to afford a tetra‐metallic complex containing a 2,3‐diphosphabutadiene‐1,1,4,4‐tetraide fragment. By contrast, non‐reductive dimerization of Ni(SIDipp)(Cp)(CP) (SIDipp=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolidin‐2‐ylidene; Cp=cyclopentadienyl), gives rise to an asymmetric bimetallic complex containing a 1,3‐diphosphacyclobutadiene‐2,4‐diide moiety. Spontaneous trimerization of Sc(Cp*)2(CP) results in the formation of a trimetallic complex containing a 1,3,5‐triphosphabenzene‐2,4,6‐triide fragment. These transformations show that while cyaphido transition metal complexes can be readily accessed using metathesis reactions, many such species are unstable to further oligomerization processes.