Reactive ion pairs from the charge-transfer excitation of electron donor-acceptor complexes.

Excitation within the charge-transfer (CT) band of the electron donor-acceptor or EDA complexes of tetranitromethane (TNM) with a series of 9- substituted and 9,10-di-substituted anthracenes (An) leads to photochemistry in high quantum yields (phi ~ 1). The combined use of time-resolved picosecond spectroscopy, product isolation and structure elucidation allows for detailed mapping of the temporal evolution of the CT excited state to the photoproduct I via a series of discrete reactive intermediates. This electron transfer within the EDA complex occurs effectively ( 25 ps) upon CT photoexcitation to form simultaneously An+/. and TNM-/. .