Axially Arylene-bridged "Dumbbell" B(III)-Subporphyrin Dimers and a Tetrameric Subporphyrin Nanocage.

Axially B-arylene-bridged "dumbbell" B III -subporphyrin (abbreviated as subporphyrin in this paper) dimers 3, 4, and 5 were prepared by reactions of B-methoxy subporphyrins with bromoaryl Grignard reagents and subsequent reductive coupling of the resulting B-bromoaryl subporphyrins with Ni(cod) 2 . This reductive coupling method was also used for synthesis of tetrameric subporphyrin nanocage 8 from meso-meso linked subporphyrin dimer 7. Nanocage 8 displayed a red-shifted Q-like band and reduced fluorescence quantum yield as compared with 6 and 7.