Heterobimetallic (Ferrocenyl)indenyl Rhodium Complexes. Synthesis, Crystal Structure, and Oxidative Activation of [η5-(1-Ferrocenyl)indenyl]RhL2 [L2 = COD, NBD, (CO)2]

The binuclear [η 5 -(1-ferrocenyl)indenyl]Rh(NBD) ( 1 ), [η 5 -(1-ferrocenyl)indenyl]Rh(COD) ( 1a ), and [η 5 -(1-ferrocenyl)indenyl]Rh(CO) 2 ( 2 ) complexes have been synthesized (NBD = norbornadiene; COD = cycloocta-1,5-diene). The crystal structure determination showed that the iron and rhodium nuclei are disposed in a transoid configuration in 1 probably to avoid steric repulsions. On the contrary, in 2 the metals are in a cisoid configuration due to the presence of stabilizing π-hydrogen bonds between the CO's and the hydrogens of the unsubstituted cyclopentadienyl ring. The results of the chemical and electrochemical oxidation of 2 are in favor of the existence of an effective interaction between the two metals.