Thermally and Photochemically Controlled Insertion of Alkynes into Clusters: A Route to Organometallic π‐Ligands

Abstract

A novel, cyclic conjugated 4π ligand containing a C2Fe2P ring is formed as complex 1 with Fe(CO)3 in the photochemical insertion of diphenylacetylene into the cluster [(μ3-RP){Fe(CO)3}3CO], R = p-methoxyphenyl. 1, with its almost planar ring, is isolobal with dihydro-1,2,5-thiadiborole ligands.—On thermal activation, a complex containing a “heterobutadiene” ligand is formed instead of 1.