Iridium Coordination to exo-Dithio-7,8-dicarba-nido-undecaborate Derivatives

Ligands incorporating two sulfur atoms directly connected to the carbon atoms of the unit 7,8-dicarba-nido-undecaborate(1—) react with [IrCl(CO)(PPh3)2] in the presence of AgNO3 in ethanol to form stable metal complexes. Each Ir(I) atom is four-coordinated to two phosphorus atoms of the PPh3 groups and the two sulfur atoms of the 7,8-dicarba-nido-undecaborate(1—)-containing ligand. The influence of the S,S′ outer chain was studied by reacting these Ir(I)-dithioether complexes with O2. The complex with a short chain ligand (six element mesocycle) decomposed, complexes with seven or eight chain atoms in the ligand did not react, and those with a noncyclic ligand reacted by oxidative addition forming a stable complex. The crystal structure of [IrO2(Ls2n)(PPh3)2]·Me2CO verified unambiguously the coordination of this peroxo complex. The compound C43H51B9IrP2O3S2 Mr = 1031.45, crystallizes in the monoclinic space group P21/n (No. 14), with a = 15.369 (1) Å, b = 19.481(2) Å, c = 16.027(4) Å, β= 101.92(1)°, V = 4695(1) Å3, Z = 4, R = 0.039, and Rw = 0.044. © 1994, American Chemical Society. All rights reserved.