The nature of the excited states of p-nitro-N,N-dimethylaniline.

Contrary to numerous derivatives of p-substituted N,N-dimethyl-aniline, p-nitro-N,N-dimethylaniline, does not form the TICT state. This behaviour is predicted by INDO/S calculations. The calculations also reveal an important role of the Coulomb interaction term in the evolution of intramolecular charge-transfer excited-state energy upon twisting of the dimethylamino group

The Geometry of the Excited Charge Transfer States: Flattening or Twisting?

Numerous molecules built of an electron acceptor and electron donor units linked together by single bond exhibit a peculiar behavior in their low-lying electronically excited states. N,N-diethylaminoacetophenone and 4-acetyl-4'-dimethylamino-biphenyl, having acetophenone as the acceptor and differentiated by the donors groups $N(CH_3)_2$ and dimethylaniline, respectively, were selected as the subject of study. To recognize the excited state relaxation paths the stationary and time-resolved spectroscopy in absorption and emission was applied. Experimental results indicate that after excitation in polar solvents N,N-diethylaminoacetophenone reduces to minimum the overlap between π-electron systems of the donor and acceptor groups relaxing to the twisted internal charge-transfer state; contrary to that, flattening of the 4-acetyl-4'-dimethylamino-biphenyl skeleton generates increase in the overlap of the π-electron systems

The Geometry of the Excited Charge Transfer States: Flattening or Twisting?

Numerous molecules built of an electron acceptor and electron donor units linked together by single bond exhibit a peculiar behavior in their low-lying electronically excited states. N,N-diethylaminoacetophenone and 4-acetyl-4'-dimethylamino-biphenyl, having acetophenone as the acceptor and differentiated by the donors groups $N(CH_3)_2$ and dimethylaniline, respectively, were selected as the subject of study. To recognize the excited state relaxation paths the stationary and time-resolved spectroscopy in absorption and emission was applied. Experimental results indicate that after excitation in polar solvents N,N-diethylaminoacetophenone reduces to minimum the overlap between π-electron systems of the donor and acceptor groups relaxing to the twisted internal charge-transfer state; contrary to that, flattening of the 4-acetyl-4'-dimethylamino-biphenyl skeleton generates increase in the overlap of the π-electron systems

Spectroscopy and Photophysics of 3'-[p-(dimethylamino)phenyl]spiro-[fluorene-9,4'-oxazolidine]-2',5'-dione

Electronic absorption and emission spectroscopy of the title molecule has been studied in solution, low-temperature glasses and polymer matrices. No luminescence could be observed down to 77 K. In the presence of water, the formation of the hydrated species was observed, accompanied by the appearance of phosphorescence. The structure and spectra of both forms were calculated using molecular mechanics and quantum chemical methods. The lack of phosphorescence in the anhydride is interpreted as due to proximity effects in the triplet manifold

LOW-TEMPERATURE DUAL FLUORESCENCE IN 9-MORPHOLINOACRIDINE PICOSECOND TICT STATE FORMATION

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PICOSECOND ABSORPTION-SPECTRA OF CARBONYL DERIVATIVES OF DIMETHYLANILINE - THE NATURE OF THE TICT EXCITED-STATES

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LOW-TEMPERATURE DUAL FLUORESCENCE IN 9-MORPHOLINOACRIDINE PICOSECOND TICT STATE FORMATION

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