(1,2,3,4,7-Pentamethylindenyl)rhodium complexes with arene ligands

The reaction of (η5-C9H2Me5)Rh(1,5-C8H12) (1) with I2 gives the iodide complex [(η5-C9H2Me5)RhI2]2 (2). The solvate complex [(η5- C9H2Me5)Rh(MeNO2)3]2+ (generated in situ by treatment of 2 with Ag+ in nitromethane) reacts with benzene and its derivatives giving the dicationic arene complexes [(η5-9H2Me5)Rh(arene)]2+ [arene = C6H6 (3a), C6Me6 (3b), C6H5OMe (3c)]. Similar reaction with the borole sandwich compound CpRh(η5-C4H4BPh) results in the arene-type complex [CpRh(μ-η5:η6-C4H4BPh)Rh(η5-C9H2Me5)]2+ (4). Treatment of 2 with CpTl in acetonitrile affords cation [(η5-C9H2Me5)RhCp]+ (5). The structure of [3c](BF4)2 was determined by X-ray diffraction. The electrochemical behaviour of complexes prepared was studied. The rhodium–benzene bonding in series of the related complexes [(ring)Rh(C6H6)]2+ (ring = Cp, Cp∗, C9H7, C9H2Me5) was analyzed using energy and charge decomposition schemes.