Mono- and diboron corroles: factors controlling stoichiometry and hydrolytic reactivity.

The first example of a diboryl corrole complex, (BF2)2(Br8T(4-F-P)C) (Br8T(4-F-P)C = trianion of 2,3,7,8,12,13,17,18-octabromo-5,10,15-tris(4-fluorophenyl)corrole), has been isolated using the strongly electron-withdrawing and sterically crowded triaryl octabromocorrole ligand. Density functional theory (DFT) calculations show that the hydrolysis reaction producing the partially hydrolyzed complexes B2OF2(Cor) is more favored for the less sterically crowded triaryl corrole complexes. Monoboryl complexes BF2(H2Cor) (Cor = trianions of 5,10,15-triphenylcorrole (TPC), 5,10,15-tris(4-methylphenyl)corrole (T(4-CH3-P)C), 5,10,15-tris(4-trifluoromethylphenyl)corrole (T(4-CF3-P)C), and 5,10,15-tris(pentafluorophenyl)corrole (TPFPC)) were prepared and characterized. The experimental data are consistent with an out-of-plane dipyrrin coordination mode for these complexes, and DFT optimizations suggest that internal BF···HN hydrogen bonding may be significant in stabilizing these complexes. Further examples of the anionic diboron corrole B2OF2(Cor) containing the electron-withdrawing 5,10,15-tris(pentafluorophenyl)corrole (TPFPC) and the sterically hindered 10-(4-methoxyphenyl)-5,15-dimesitylcorrole (Mes2(4-MeOP)C) trianions are reported.