Synthesis, Reactivities, and Catalytic Properties of Iodo-Bridged Polymeric Iridium Complexes with Flexible Carbon Chain-Bridged Bis(tetramethylcyclopentadienyl) Ligands

Abstract

Dinuclear iridium complexes [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )][Ir(COD)] 2 ( 2a: n = 2; 2b: n = 3; 2c: n = 4) are obtained from the reactions of the corresponding dilithium salts Li 2 [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )] ( n = 2–4) with [Ir(μ-Cl)(COD)] 2 . Further oxidation of 2 affords iodo-bridged polymeric iridium complexes [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )(IrI 2 ) 2 ] m ( 3a: n = 2; 3b: n = 3; 3c: n = 4). Dinuclear iridium complexes [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )][IrI 2 (PPh 3 )] 2 ( 4a: n = 2; 4b: n = 3; 4c: n = 4) and [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )][IrI 2 (CO)] 2 ( 5b: n = 3; 5c: n = 4) are obtained from the reactions of 3 with PPh 3 and CO, respectively. Dinuclear dicarbonyl iridium complexes [(C 5 Me 4 )(CH 2 ) n (C 5 Me 4 )][Ir(CO) 2 ] 2 ( 6b: n = 3; 6c: n = 4) are obtained from the reactions of 3 with Zn and CO. Additionally, the cyclometalated dinuclear iridium complexes 7b, c, 8b, c, 9b, c, and 10b, c are obtained from the reactions of 3 with the corresponding nitrogen ligands in the presence of KOH. The molecular structures of complexes 2a, 4a, 5b, 6c, and 7b have been determined by single-crystal X-ray diffraction analysis. Moreover, we found that complexes 3 and 4 are efficient catalysts for the selective amine cross-coupling reaction.