N,N-dialkylanilines: The S-1 state absorption spectrum and efficient intramolecular triplet-triplet energy transfer to an olefinic bond

Efficient intramolecular triplet-triplet energy transfer from an N,N-dialky lanilino donor to an alkene acceptor was observed in 4-(4-(propan-2-ylidene )cyclohexyl)-N,N-dimethylaniline (2) and 1-phenyl-4-cyclohexylidene-piperid ine (4) using nanosecond transient absorption spectroscopy and time-resolve d microwave conductivity. This enables the unequivocal assignment of the ab sorption spectrum of the first singlet excited state of the N,N-dialkylanil ino chromophore in 4-cyclohexyl-N,N-dimethylaniline (1), 2, 1-phenyl-4-cycl ohexylpiperidine (3) and 4. It has a maximum positioned between 600 and 635 nm.