A Stable Iridabenzene Formed from an Iridacyclopentadiene Where the Additional Ring-Carbon Atom Is Derived from a Thiocarbonyl Ligand

The cationic thiocarbonyl complex [Ir(CS)(MeCN)(PPh3)2][CF3SO3] (1) reacts sequentially with ethyne and LiCl to give the iridacyclopentadiene Ir[C4H4]Cl(CS)(PPh3)2 (2), which in turn when heated with methyl triflate followed by addition of LiCl produces the stable, purple, iridabenzene Ir[C5H4(SMe-1)]Cl2(PPh3)2 (3). This iridabenzene undergoes electrophilic aromatic bromination in the position para to the SMe substituent to form Ir[C5H3(SMe-1)(Br-4)]Br2(PPh3)2 (4).