3H-Pyrrolo[2,3-b]pyridinium,7-[(4-boronophenyl)methyl]-2-[3-[7-[(4-boronophenyl)methyl]-3,7-dihydro-3,3-dimethyl-2H-pyrrolo[2,3-b]pyridin-2-ylidene]-1-propenyl]-3,3-dimethyl-, bromide