Peripherally Substituted Phthalocyanines

Peripherally substituted phthalocyanine (Pc) systems render more accessible the desirable properties of the Pc system, i.e., high thermal and oxidative stability as well as significant complexity ability of transition metals. After brief examination of existing synthetic methods, two new routes to substitution of the peripheral protons of the Pc system are described: (1) directed metalation of the Pc system itself followed by derivatization, and (2) directed metalation of phthalonitrile followed by derivatization and Pc formation. Each of these methods is further distinguished by providing exclusively substitution at the a-positions of the Pc nucleus. Several of the compounds have been isolated and characterized using the techniques of HPLC; ¹H, ¹³C, and ²⁹Si NMR; and mass spectroscopy. These multisubstituted Pc systems are much more soluble in organic solvents than is the parent system. Such soluble macromolecules are of interest to the energy research community because of a variety of possible applications, notably the preparation of sensors, electrode coatings, catalysts, and soluble oxygen transports.