N,N-dialkylanilines: The S1 state absorption spectrum and efficient intramolecular triplet-triplet energy transfer to an olefinic bond

Abstract

Efficient intramolecular triplet-triplet energy transfer from an N,N-dialkylanilino donor to an alkene acceptor was observed in 4-(4-(propan-2-ylidene)cyclohexyl)-N,N-dimethylaniline (2) and 1-phenyl-4-cyclohexylidenepiperidine (4) using nanosecond transient absorption spectroscopy and time-resolved microwave conductivity. This enables the unequivocal assignment of the absorption spectrum of the first singlet excited state of the N,N-dialkylanilino chromophore in 4-cyclohexyl-N,N-dimethylaniline (1), 2, 1-phenyl-4-cyclohexylpiperidine (3) and 4. It has a maximum positioned between 600 and 635 nm