Excited States Dipole Moments and Fluorescence Behaviour of Some Derivatives of Dimethylaminobenzonitrile

1990 ◽  
Vol 45 (7) ◽  
pp. 883-888
Author(s):  
C. Brittinger ◽  
A. K. Maiti ◽  
W. Baumann ◽  
N. Detzer
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Intramolecular Charge Transfer ◽  
Dipole Moments ◽  
Solvent Polarity ◽  
Polar Solvents ◽  
Derivatives Of ◽  
Limiting Value

AbstractTwo sterically hindered derivatives of dimethylaminobenzonitrile (DMCA) have been synthesized and the dipole moment of their fluorescent excited state has been determined in differently polar solvents. Its value increases with solvent polarity up to a limiting value of (50 + 2.5) • 10-30 Cm. The results are discussed with reference to the twisted intramolecular charge transfer (TICT) state formation in the class of molecules related to DMCA.

Spectroscopic Studies of Dimethylamino Derivatives of Fluorene

2000 ◽  
Vol 55 (11-12) ◽  
pp. 902-908 ◽  
Author(s):  
J. Heldt ◽  
J. R. Heldt ◽  
T. Redzimski ◽  
H. Diehl ◽  
P. Schultz
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Spectroscopic Studies ◽  
Polar Solvents ◽  
Derivatives Of ◽  
Transfer State

Abstract 2-dimethylamino-9-fluorenol and 2-dimethylamino-9(4'dimethylamino)phenyl-9-fiuorenol in polar solvents in the excited state undergo conformation changes in which two fluorescent isomers are created. The isomers (in the local excited (LE) and charge transfer (CT) configuration) possess separate fluorescence bands, one appearing from the S1 (LE) state and the second from the intramolecular charge transfer state S1 (CT) of the neutral, aromatic molecule. Both bands show a solvatochromic effect. Using the method of the solvent induced Stokes shift of the absorption and fluorescence spectra the permanent dipole moment of the excited state of fluorene and its two derivatives have been determined. The dipole moment of the ground state and the Onsager cavity radius of the studied molecules were calculated with the Auestion Model 1 (AM1) program.

Solvent sensitive intramolecular charge transfer dynamics in the excited states of 4-N,N-dimethylamino-4′-nitrobiphenyl

2016 ◽  
Vol 18 (11) ◽  
pp. 7661-7671 ◽  
Author(s):  
Rajib Ghosh ◽  
Amitabha Nandi ◽  
Dipak K. Palit
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Triplet State ◽  
Excited States ◽  
Intramolecular Charge Transfer ◽  
Intersystem Crossing ◽  
Polar Solvents ◽  
Excited State Dynamics ◽  
Nonpolar Solvents ◽  
Charge Transfer Dynamics

Solvent sensitive excited state dynamics of DNBP is explored. In polar solvents, the ultrafast barrierless TICT process is the major relaxation pathway, whereas, in nonpolar solvents the excited state undergoes the PICT process, followed by efficient intersystem crossing to the triplet state.

CHAMELEON GROUND STATE AND EXCITED STATES OF EDT-TTF-IM-F4TCNQ RADICAL DYAD IN DIFFERENT ENVIRONMENTS

2012 ◽  
Vol 11 (03) ◽  
pp. 505-525 ◽  
Author(s):  
YUHUA ZHOU ◽  
KAI TAN ◽  
XIN LU
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Solvent Polarity ◽  
Functional Study ◽  
Polar Solvents ◽  
Model Calculations ◽  
A Charge

We have performed a systematic density functional study on the ground-state electronic structure and excited states of a representative D-σ-A dyad, i.e. EDT-TTF-Im-F4TCNQ π-radical, in vacuo and in different conventional solvents (toluene, THF, DMF and DMSO) by using some popular hybrid density functionals (B3LYP, M05, M05-2X, PBE0 and BMK). It has been shown that the M05 and B3LYP functionals perform the best in predicting the intramolecular charge-transfer (ICT) pertaining to both the ground state and excited states of the dyad. The amphoteric dyad is liable to solvent-promoted ICT from its EDT-TTF-Im donor (D) to F4TCNQ acceptor (A), adopting a charge-unseparated ground state D-A• in vacuo, a partially zwitterionic ground state [D-A]• in nonpolar toluene solvent, and a fully zwitterionic ground state D•+-A- in such polar solvents as THF, DMF and DMSO. Owing to its solvent-dependent chameleon ground state, excited states of the dyad in solvents also exhibit remarkable dependence on solvent polarity, as revealed by TDDFT calculations. Furthermore, cluster model calculations revealed that intermolecular charge-transfer readily occurs between the dyads, accounting for the observed zwitterionic charge state in solid state and solid-state semiconductivity.

scholarly journals Crystal Structures and Optical Properties of Two Novel 1,3,5-Trisubstituted Pyrazoline Derivatives

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 467
Author(s):  
Qi Feng ◽  
Wenhui Huan ◽  
Jiali Wang ◽  
Jiadan Lu ◽  
Guowang Diao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Solid State ◽  
Physical Properties ◽  
Intramolecular Charge Transfer ◽  
Solvent Polarity ◽  
Dihedral Angles ◽  
Polar Solvents ◽  
X Ray ◽  
X Ray Crystallography

Two novel 1,3,5-trisubstituted pyrazoline derivatives—1-acetyl-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphthyl)-pyrazoline (2a) and 1-(4-nitrophenyl)-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphtyl)-pyrazoline (2b)—were synthesized and their structures were determined by single crystal X-ray crystallography. Both of the two crystals exhibit twisted structures due to the large dihedral angles between the pyrazolinyl ring and the aromatic ring at the 5-position (88.09° for 2a and 71.26° for 2b). The optical–physical properties of the two compounds were investigated. The fluorescent emission of 2b arises from the 1,3-disubstituted pyrazoline chromophores and exhibits a red shift in polar solvents and solid-state, which could be attributed to photo-induced intramolecular charge transfer (ICT) from N1 to C3 in the pyrazoline moiety and the intermolecular interactions within the crystal. The fluorescent emissions of 2a (λmax 358–364 nm) in solvents and solid-state both come from 6-methoxy-2-naphthyl chromophores, which are fairly insensitive to the solvent polarity.

Intramolecular fluorescence quenching in aminocoumarines. Identification of an excited state with full charge separation

1985 ◽  
Vol 63 (7) ◽  
pp. 1649-1653 ◽  
Author(s):  
Wolfgang Rettig ◽  
André Klock
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Charge Separation ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Twisted Intramolecular Charge Transfer ◽  
Full Charge

The fluorescence of 6-aminocoumarine (A6C) is very weak and anomalously redshifted as compared to its 7-substituted analogues 4-methyl-7-aminocoumarine (A7C) and 4-methyl-7-diethylaminocoumarine (DEA7C). The solvatochromic redshift in homologous alcohols is much stronger for A6C, pointing to an increased dipole moment of the emitting state. A twisted intramolecular charge transfer (TICT) state with full charge separation is made responsible for this emission. This is rationalized by molecules-in-molecules calculations. The strong Stokes shift in n-hexane and in ethanol glass at 77 K suggests that A6C emits from a TICT state even under these conditions.

scholarly journals Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

2010 ◽  
Vol 6 ◽  
pp. 992-1001 ◽  
Author(s):  
Ritesh Nandy ◽  
Sethuraman Sankararaman
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Linear Correlation ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Donor And Acceptor ◽  
Electron Donor And Acceptor ◽  
Stokes Shifts

Several 2-(phenylethynyl)triphenylene derivatives bearing electron donor and acceptor substituents on the phenyl rings have been synthesized. The absorption and fluorescence emission properties of these molecules have been studied in solvents of different polarity. For a given derivative, solvent polarity had minimal effect on the absorption maxima. However, for a given solvent the absorption maxima red shifted with increasing conjugation of the substituent. The fluorescence emission of these derivatives was very sensitive to solvent polarity. In the presence of strongly electron withdrawing (–CN) and strongly electron donating (–NMe2) substituents large Stokes shifts (up to 130 nm, 7828 cm−1) were observed in DMSO. In the presence of carbonyl substituents (–COMe and –COPh), the largest Stokes shift (140 nm, 8163 cm−1) was observed in ethanol. Linear correlation was observed for the Stokes shifts in a Lippert–Mataga plot. Linear correlation of Stokes shift was also observed with E T(30) scale for protic and aprotic solvents but with different slopes. These results indicate that the fluorescence emission arises from excited state intramolecular charge transfer in these molecules where the triphenylene chromophore acts either as a donor or as an acceptor depending upon the nature of the substituent on the phenyl ring. HOMO–LUMO energy gaps have been estimated from the electrochemical and spectral data for these derivatives. The HOMO and LUMO surfaces were obtained from DFT calculations.

Structural Requirements for Intramolecular Charge-Transfer in Excited State of 4-(9-Anthryl)-N,N-dimethylaniline

1982 ◽  
Vol 37 (6) ◽  
pp. 598-606 ◽  
Author(s):  
Aleksander Siemiarczuk ◽  
Jacek Koput ◽  
Andrzej Pohorille
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dipole Moments ◽  
Atomic Charge ◽  
Transfer Model ◽  
Charge Densities ◽  
Singlet States ◽  
Donor And Acceptor ◽  
Electron Donor And Acceptor

Abstract Excited state kinetics and other photophysical features of 4-(9-anthryl)-N,N-dimethylaniline and two model compounds have been thoroughly examined in order to establish the structural conditions for highly polar excited state formation.Also quantum chemical calculations by means of INDO/S CI and PCILO methods have been performed to obtain potential energy curves, dipole moments and atomic charge densities for the ground and lowest excited singlet states as a function of the angle of twist between anthryl and dimethylaniline subunits.Both the experimental and theoretical results confirm the previously proposed TICT (Twisted Intramolecular Charge-Transfer) model predicting the perpendicularity between electron donor and acceptor moieties as a condition for nearly full charge-separation in excited states for some classes of aromatic compounds.

A TWO-FORM DESCRIPTION OF PUSH-PULL MOLECULES: CORRELATIONS BETWEEN STRUCTURE, INTRAMOLECULAR CHARGE TRANSFER AND (HYPER) POLARIZABILITIES

1996 ◽  
Vol 05 (04) ◽  
pp. 757-765 ◽  
Author(s):  
M. BARZOUKAS ◽  
A. FORT ◽  
M. BLANCHARD-DESCE
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Intramolecular Charge Transfer ◽  
Ground States ◽  
Solvent Polarity ◽  
Reaction Field ◽  
Donor Acceptor ◽  
Semi Empirical ◽  
Relevant Factors ◽  
Acceptor Molecules

We present a quantum two-form two-state description of donor-acceptor molecules. We single out relevant factors that are characteristic of the molecule and its environment. In addition, we define a parameter which rules the geometry of both ground and excited states. Also, this parameter is proportional to the change in dipole between excited and ground states. We show that correlations between (hyper)polarizabilities and this parameter reproduce remarkably well semi-empirical predictions. We extend this model in order to account for the solvent reaction field. This model helps in the understanding of the dependencies of (hyper)polarizabilities on solvent polarity.

Fluorinated 9,9′-bianthracene derivatives with twisted intramolecular charge-transfer excited states as blue host materials for high-performance fluorescent electroluminescence

2014 ◽  
Vol 2 (44) ◽  
pp. 9375-9384 ◽  
Author(s):  
Yue Yu ◽  
Bo Jiao ◽  
Zhaoxin Wu ◽  
Zhanfeng Li ◽  
Lin Ma ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
High Performance ◽  
Intramolecular Charge Transfer ◽  
Twisted Intramolecular Charge Transfer ◽  
Host Materials

We report the electroluminescent performance of a series of fluorinated 9,9′-bianthracene derivatives with particular twisted intramolecular charge transfer excited state to serve as host materials.

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