Fast Internal Conversion, Dual Fluorescence and Intramolecular Charge Transfer in 9-Cyano-10-(Dimethylamino)Anthracene#

Druzhinin, S. I.; Demeter, Attila; Niebuer, Meinhard; Tauer, Erich; Zachariasse, Klaas A.

doi:10.1163/156856799x00545

Cited by 12 publications

(28 citation statements)

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“…9,10-Bis(phenylethynyl)anthracene (BPEA), 9-methylanthracene (9MeA) and 9,10diphenylanthracene (DPhA) were received from Aldrich and were purified on a silica column using n-hexane -dichloromethane eluent and recrystallized from toluene For triplet yield determination the energy transfer method was used where excited anthracene was the energy donor, and triplet yield standard, 27 and BPEA the acceptor, similar to our previous experiments on 9-ciano-10-(dimethylamino)anthracene. 28 This set-up is adequate when the expected triplet energy as well as the triplet yield is small.…”

Section: Methodsmentioning

confidence: 99%

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First Steps in Photophysics. I. Fluorescence Yield and Radiative Rate Coefficient of 9,10-Bis(phenylethynyl)anthracene in Paraffins

Demeter

2014

J. Phys. Chem. A

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The fluorescence quantum yield of 9,10-bis(phenylethynyl)anthracene (BPEA) is almost unity in every examined solvent. Using different hydrocarbons, one can make a convenient and sufficiently accurate experimental test for determination of the extent of the refractive index correction needed in fluorescence quantum yield determination on a given fluorometer. By comparison of the measurements in n-pentane-cis-decaline or n-hexane-toluene solvent pairs, the requirement of the n(2) correction is confirmed for most of the fluorometers; however, for one of the examined pieces of equipment the necessary correction proved to be slightly lower. By excited state's lifetime measurements, the refractive index dependence of the fluorescence rate coefficient was reexamined. At 25 °C for BPEA the relationship is in agreement with Bakhshiev's prediction: the experimentally determined exponent of n in the rate coefficient deriving equation is around 1.32 using different paraffins as solvents. The negative temperature coefficient of the radiative rate in part originates from the temperature dependence of the refractive index, while also a small intrinsic contribution has been found.

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Section: Methodsmentioning

confidence: 99%

“…The pseudo first order energy transfer occurs typically on the 3-4 µs range while the anthracene itself decays on a much slower timescale (400-600 µs). The triplet yields of anthracene donor were taken to be 0.71 in n-hexane (and HD), 27,28 while 0.66 in acetonitrile 27 respectively.…”

Section: Methodsmentioning

confidence: 99%

First Steps in Photophysics. I. Fluorescence Yield and Radiative Rate Coefficient of 9,10-Bis(phenylethynyl)anthracene in Paraffins

Demeter

2014

J. Phys. Chem. A

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“…Efficient thermally activated internal conversion has, however, been observed with a number of other aromatic amines: 3,5-dimethyl-4-(methylamino)benzonitrile (MHD), 9 1-(dialkylamino)naphthalenes, [10][11][12][13][14][15] a series of 4-substituted 1-(dimethylamino)naphthalenes 15 and 9-(dimethylamino)anthracenes. 16 It has been shown that the occurrence of this internal conversion is governed by the twist angle of the amino group relative to the plane of the aromatic moiety, as well as by the energy gap DE(S 1 ,S 2 ) between the two lowest excited singlet states. [12][13][14][15][16] The IC reaction has been assumed to proceed from S 1 to S 0 via a conical intersection.…”

Section: Introductionmentioning

confidence: 99%

“…16 It has been shown that the occurrence of this internal conversion is governed by the twist angle of the amino group relative to the plane of the aromatic moiety, as well as by the energy gap DE(S 1 ,S 2 ) between the two lowest excited singlet states. [12][13][14][15][16] The IC reaction has been assumed to proceed from S 1 to S 0 via a conical intersection. 14,15,17 During an investigation of the influence of fluoro substitution in the phenyl ring of aminobenzonitriles on the efficiency of ICT in the singlet excited state, 18 it was found that with P4CF2 and P4CF3 in alkane solvents the F-substitution opens up an efficient internal conversion channel.…”

Section: Introductionmentioning

confidence: 99%

Internal conversion with 4-(azetidinyl)benzonitriles in alkane solvents. Influence of fluoro substitution

Druzhinin

Jiang

Demeter

et al. 2001

Phys. Chem. Chem. Phys.

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The introduction of a fluoro-substituent in the phenyl ring of 4-(1-azetidinyl)benzonitrile (P4C) leads to smaller fluorescence quantum yields Phi (f) and shorter decay times tau in alkane solvents (cyclopentane, n-hexadecane, n-hexane and 2-methylpentane). In cyclopentane at 25 degreesC, Phi (f) and tau equal 0.02 and 0.14 ns for 2-fluoro-4-(1-azetidinyl)benzonitrile (P4CF2) and 0.11 and 0.85 ns for 3-fluoro-4-(1-azetidinyl)benzonitrile (P4CF3), as compared with 0.27 and 4.55 ns for P4C. The fluorescence originates from a locally excited (LE) state and dual fluorescence due to intramolecular charge transfer is not observed for the three aminobenzonitriles at any temperature in the alkane solvents. By measuring the yields of intersystem crossing Phi (ISC), it follows that this enhancement of the radiationless deactivation of the first excited singlet state S-1 is due to thermally activated internal conversion (IC). The IC yield Phi (IC) in cyclopentane at 25 degreesC, as an example, is considerably larger for P4CF2 (0.93) than for P4CF3 (0.35) and of minor importance for P4C (0.03). The IC activation energies E-IC of P4CF2 (12.6 kJ mol(-1)), P4CF3 (19.3 kJ mol(-1)) and P4C (38.1 kJ mol(-1)) in cyclopentane were determined by fitting tau measured as a function of temperature, together with data for Phi (f) and Phi (ISC). Similar E-IC values were obtained in n-hexane and n-hexadecane. These data show that the increase in IC efficiency from P4C via P4CF3 to P4CF2 is caused by a decrease in E-IC. The radiative rate constants k(f) in cyclopentane of P4CF2 and P4CF3 are about twice that of P4C, probably due to the mixing of the S-2(L-1(a),CT) and S-1(L-1(b)) states of P4C caused by the molecular asymmetry introduced by the F-substituents. It is assumed that the lowering of the IC barriers in P4CF2 and P4CF3 is governed by an F-substituent-dependent difference in the energies of the molecular configuration of the azetidinylbenzonitriles that can be reached in S-1 as compared with those in S-0

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“…The intramolecular charge transfer process in anthracene derivatives Table 7 The excited state (S1) dipole moments (µE) (in Debye) of two pairs of isomeric molecules and the first three vertical transitions energies (∆ E1, ∆ E2 and ∆ E3) (in eV) and oscillator strengths (fS0−S1, fS0−S2 and fS0−S3) calculated by CIS theory and employing 6-31G** basis set in Gaussian03. The ground state dipole moment (µG) (in Debye) has been reported for comparison has been studied experimentally by Muralidharan [40,41]and Zachariasse [42]. Muralidharan [40] and coworkers have studied the photophysical properties of a series of 9,10-donor-acceptor substituted anthracene molecules.…”

Section: The Structure and Properties Of The Molecules Studiedmentioning

confidence: 99%

Exploring NLO response of 9,10- donor-acceptor substituted Bichromophoric Anthracene Derivatives

Misra

Sharma

Bhattacharyya

2010

JCM

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Ab-initio finite field SCF calculations with split valence double zeta basis set indicate that 9, 10-donor-acceptor substituted anthracene derivatives have large quadratic hyperpolarizabilities for suitable combinations of donor and acceptor moieties. A difference in the first hyperpolarizabilities (β total ) of isomeric organic chromophores containing the same donor and acceptor groups indicate the possible role of intramolecular charge transfer (ICT) in shaping the NLO response in these π-conjugated molecular chromophores. A correlation is sought to be established among calculated β total on one hand and the donor strength, the strength of the acceptor, donor-acceptor interaction and the donor-acceptor separation, on the other by using Genetic Algorithm (GA) to search through the relevant parameter space. It appears that β total of a molecule is dominantly determined by additive contributions from the donors and the acceptors. The results might be helpful in designing new NLO materials using the bichromophoric anthracene derivatives.

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Fast Internal Conversion, Dual Fluorescence and Intramolecular Charge Transfer in 9-Cyano-10-(Dimethylamino)Anthracene#

Cited by 12 publications

References 0 publications

First Steps in Photophysics. I. Fluorescence Yield and Radiative Rate Coefficient of 9,10-Bis(phenylethynyl)anthracene in Paraffins

First Steps in Photophysics. I. Fluorescence Yield and Radiative Rate Coefficient of 9,10-Bis(phenylethynyl)anthracene in Paraffins

Internal conversion with 4-(azetidinyl)benzonitriles in alkane solvents. Influence of fluoro substitution

Exploring NLO response of 9,10- donor-acceptor substituted Bichromophoric Anthracene Derivatives

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