Reactivity Studies of a Hydroxy-Substituted Irida-carbolong Complex

The reactivities of the aromatic β-hydroxy-substituted irida-carbolong complex [Ir­{CHC­(CH2C­(CO2Me)2CH2)CCCHC­(OH)CH}­(CO)­(PPh3)2]­BF4 (1) with a series of reagents, including AcCl, (CF3CO)2O, NaOH, Et2NSF3 and NaNO2/HBF4·H2O, were studied, affording five new complexes [Ir­{CHC­(CH2C­(CO2Me)2CH2)CCCHC­(OCOCH3)CH}­(CO)­(PPh3)2]­BF4 (2), [Ir­{CHC­(CH2C­(CO2Me)2CH2)CC=CHC­(OCOCF3)CH}­(CO)­(PPh3)2]­BF4 (3), [Ir­{CHC­(CH2C­(CO2Me)2CH)­CCCHC­(O)­CH2}­(CO)­(PPh3)2] (4), [Ir­{CHC­(CH2C­(CO2Me)2CH2)CCCHC­(F)CH}­(CO)­(PPh3)2]­BF4 (5), and [Ir­{C­(O)­C­(CH2C­(CO2Me)2CH2)CCCHC­(O)­CHN­(OH)}­(NO2)­(PPh3)2] (6), in the yields of 61–87%, respectively. Each of complexes 2, 3 and 5 still contains an iridapentalene fragment. In contrast, the [5,5]-fused iridabicycle in complex 4 is dearomatized, and the alteration of the metallabicycle skeleton was involved during the preparation of 6, with the transformation from a [5,5]-fused iridabicycle to a ring-expansion [5,6]-fused iridabicycle.