Synthesis of phthalocyanine dimers and trimers connected via a nitrogen atom and amino phenyl groups

Abstract

Methods for the preparation of a variety of covalently linked Pc–Pc homo-dimers (ortho and meta), heterodimers and Pc–Pc triads linked through NH and bridged viaN-aryl (phenyl) groups were developed. The palladium catalyzed intermolecular carbon–nitrogen coupling reaction (Buchwald–Hartwig) between Pc-iodo and Pc-amino phthalocyanine derivatives was used for these studies. Photophysical data reveal energy transfer between the Pc moieties resulting in the appearance of new red-shift Q-bands that correlate to the planarity and dihedral angle between the subunits. The shift and the nature of Q-band depend on the number of phenyl groups, the number of Pc and the position of attachment on the phenyl ring.