Synthesis, characterization and photophysical properties of a melamine-mediated hydrogen-bound phthalocyanine–perylenediimide assembly

Abstract

The synthesis and supramolecular organization of a phthalocyanine 3 functionalized with a melamine moiety is described. 3 self-assembles in solution to form dimeric species – driven by double hydrogen-bonding between the aromatic amine functionality that is directly attached to the phthalocyanine ring and the melamine pyridinic nitrogens. In the presence of perylenediimide 2, endowed with a complementary tritopic functionality, electron donor–acceptor assembly Pc–PDI (3)₂22222·2 is spontaneously formed. (3)₂22222·2 consists of two phthalocyanines of type 3 and a perylenediimide 2, connected via triple hydrogen bonding between the melamine and the complementary unsubstituted imido functions. Electronic interactions between 2 and 3 in (3)₂22222·2 give rise, upon selective photoexcitation of 2, to an intramolecular electron transfer, affording a several nanosecond lived PDI˙⁻/H₂Pc˙⁺ species, while photoexcitation of 3 is only followed by an ordinary intersystem crossing.