Intramolecular charge transfer of 4-(dimethylamino)benzonitrile probed by time-resolved fluorescence and transient absorption: No evidence for two ICT states and a πσ* reaction intermediate

Abstract

For the double exponential fluorescence decays of the locally excited (LE) and intramolecular charge transfer (ICT) states of 4-(dimethylamino)benzonitrile (DMABN) in acetonitrile (MeCN) the same times τ1 and τ2 are observed. This means that the reversible LE⇄ICT reaction, starting from the initially excited LE state, can be adequately described by a two state mechanism. The most important factor responsible for the sometimes experimentally observed differences in the nanosecond decay time, with τ1(LE)