Molecular recognition and chemistry in restricted reaction spaces. Photophysics and photoinduced electron transfer on the surfaces of micelles, dendrimers, and DNA

This Account is concerned with molecular recognition in bimolecular reactions1 that occur in restricted spaces. Bimolecular reactions of interest are photoinduced electron transfers for which the reactants are positively electronically excited metal complexes (Figure 1) and another positively charged gegenion, either a metal complex or methyl viologen (MV^(2+)) that serves as an electron acceptor. The restricted reaction spaces are the interfacial regions of anionically charged polyions such as micelles, starburst dendrimers, and DNA. recognition is concerned with how specific sites on a molecular receptor are recognized by a binding substrate. Knowledge of the underlying principles of molecular recognition is useful in diverse activities such as the design of site- and conformation-specific reagents for biomolecules, the rational design of drugs and probes of polymer structure, the design of efficient catalytic systems, the design of strategies leading to the synthesis of new materials, and the design of novel nanoscopic devices.