The Electronic Structure of Excited N,N-Dimethyl-α-naphthylamine

Solvent-Dependent Radiationless Transitions of Excited 1-Aminonaphthalene Derivatives

“…In MMAN, a slight red shift in the 1 L a band is seen, which can be attributed to the mesomeric effect (-E effect) of the methyl group. In 2MMMAN, the N -methylamino group is twisted against the naphthalene ring plane by steric effects of the peri-hydrogen atom and the 2-methyl group, resulting in a blue shift of the 1 L a band. , The -E effect of dialkyl substituents in DMAN and DEAN is found to compensate for the blue shift caused by their twisted structures. The blue shifts observed in the absorption bands of N , N -dialkylamino compounds imply that in these two compounds the amino group is twisted to the naphthalene ring plane owing to repulsion between the alkyl substituents on the nitrogen atom and the peri-hydrogen atom on the naphthalene ring.…”

“…According to MO descriptions taking configuration interactions into account, Ψ f may be represented by 14 where Ψ i (LE) and Ψ j (CT) denote various electronic states of locally excited (LE) and charge transfer (CT) configurations, respectively. The remarkable stabilization by solvent relaxation in polar MeCN suggests the large dipole moment in the emitting state, and thus substantial CT character should be involved in the fluorescent state in polar solvents . The fact that the |M 1u | value decreased with an increase of solvent polarity excludes a simple level inversion model, since the oscillator strength of the 1 L a state is calculated to be significantly larger than that of the 1 L b state (see Table ).…”

The TICT Mechanism in 9,9‘-Biaryl Compounds: Solvatochromism of 9,9‘-Bianthryl, N-(9-Anthryl)carbazole, and N,N‘-Bicarbazyl

“…The solvatochromism of fluorophores is usually assessed from their Stokes shifts, i.e. from the difference between the frequencies of their absorption (ν̃ a ) and emission maxima (ν̃ f ) in various solvents; data are processed by applying the simplified relations derived by Lippert , and Mataga et al., − based on the theory of Ooshika, which are of the form or from the more universal relation developed by Bakshiev on the basis of the Onsager model: …”

Temperature effects on charge transfer fluorescence spectra and mechanisms of charge transfer interactions in the excited electronic state

“…These facts seem to support our previous conclusion [1] that the dimethylamino group is primarily concerned with the CT interaction of excited perylene with aromatic amines. Because, in ~-DMNA, the steric repression of the resonance effect of the substituent is very strong in contrast to the case of fi-DMNA and DMA [2,3] the ionization potential of the dimethylamino group of ~-DMNA may be smaller than that of fi-DMNA or DMA, which may result to the longer wavelength CT fluorescence in the former. Moreover, in the case of DMT, the existence of p-methyl group may decrease the ionization potential of the dimethylamino group whereas such effect may be very small in the case of m-DMT.…”