meso-Functionalization of Boron(III) Subporphyrin with Boron(III) meso-Lithiosubporphyrin.

Boron(III) meso-lithiosubporphyrin was prepared by bromine-lithium exchange of B-tolyl BIII meso-bromosubporphyrin with n-butyllithium at -98 °C. The resulting subporphyrinyllithium was treated with various electrophiles such as benzophenone, N,N-dimethylformamide, CO2 , chlorotrimethylsilane, N-fluorobenzenesulfonimide, and dimesitylboryl fluoride to give the corresponding meso-functionalized BIII subporphyrins. The nucleophile was also used to construct BIII subporphyrin dimers such as bis(BIII subporphyrinyl)ketone, bis(BIII subporphyrinyl)carbinol, and disilane-bridged BIII subporphyrin dimer. The structural, optical, and electrochemical properties of these meso-functionalized BIII subporphyrins were examined by UV/Vis absorption and fluorescence spectroscopy, electrochemical studies, and DFT calculations.