Experimental Determination of Electron Affinities of Organic Molecules

The electron affinity of a molecule is the definitive measure of its ability to act as an electron acceptor. During the past twenty years, experimental methods for the determination of this quantity have been developed. While the magnetron procedure and the electron capture detector method were introduced in the 1960s, only recently have confirmatory gas phase measurements been made. In this review, the experimental procedures and their limitations will be summarized, the available experimental results (about 200 values) will be critically evaluated, and the gas phase measurements will be compared with half wave reduction potentials. A method for estimating electron affinities from substituent effects will be presented.