N,N-Dialkylanilines:  The S₁ State Absorption Spectrum and Efficient Intramolecular Triplet−Triplet Energy Transfer to an Olefinic Bond

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.