Tetranuclear Complexes as Intermediates in Transannular Oxidative‐Addition Reactions. Structure of the First Tetrairidium Linear Cluster

Light-induced I2-addition to the Ir2 complex 1 in a normal oxidative addition in CH2Cl2 gives the corresponding Ir2 complex with an Ir-Ir bond, whereas in the same reaction in toluene without irradiation the linear Ir4 cluster 2 is formed. The central, unbridged IrIr bond has a length of 2.828(2) Å; the two outer IrIr bonds (2.731(2) Å) are symmetrically bridged by the four coordinating ligands via S- and N-atoms (see below).