Photoinduced Triplet−Triplet Energy Transfer via the 2-Ureido-41H-pyrimidinone Self-Complementary Quadruple Hydrogen-Bonded Module.

Phosphorescence quenching and flash photolysis experiments demonstrate that photoinduced intra-assembly triplet−triplet energy transfer can take place via a 2-ureido-41H-pyrimidinone-bridged benzophenone−naphthalene assembly Iwith a rate constant of 3.0 × 106s-1and an efficiency of 95% in CH2Cl2. This new finding suggests that with high binding strength and directionality, the 2-ureido-41H-pyrimidinone hydrogen-bonded module may serve as a new model to illustrate the fundamental principles governing the triplet−triplet energy-transfer process through hydrogen bonds. [ABSTRACT FROM AUTHOR]