Theoretical study of trans-cis photoisomerism in polymethine cyanines

Momicchioli, Fabio; Baraldi, Ivan; Berthier, G.

doi:10.1016/0301-0104(88)87036-8

Cited by 113 publications

(100 citation statements)

References 30 publications

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“…1 H NMR and 13 C NMR spectra were recorded in CDCl 3 on a JEOL EX 400 spectrometer at ambient temperature. NMR chemical shifts are expressed relative to TMS as the internal standard.…”

Section: Methodsmentioning

confidence: 99%

“…For instance, twisting of single and/or double bonds can readily dissipate the excitation energy. [13] Other researchers identified the many vibrational degrees of freedom as a major nonradiative pathway for flexible and semiflexible cyanines. [14] Even for largely rigid or bridged cyanines, the remaining flexible bonds can still be an effective funnel for nonemissive deactivation.…”

Section: Introductionmentioning

confidence: 99%

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Boron–Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors—en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range

Shen

Röhr

Rurack

et al. 2004

Chemistry A European J

219

157

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The X-ray crystallographic, optical spectroscopic, and electrochemical properties of a newly synthesized class of boron-diindomethene (BDI) dyes and their tetrahydrobicyclo precursors (bc-BDP) are presented. The BDI chromophore was designed to show intensive absorption and strong fluorescence in an applicationary advantageous spectral range. Its modular architecture permits fusion of a second subunit, for example, a receptor moiety to the dye's core to yield directly linked yet perpendicularly prearranged composite systems. The synthesis was developed to allow facile tuning of the chromophore platform and to thus adjust its redox properties. X-ray analysis revealed a pronounced planarity of the chromophore in the case of the BDIs, which led to a remarkable close packing in the crystal of the simplest derivative. On the other hand, deviation from planarity was found for the diester-substituted bc-BDP benzocrown that exhibits a "butterfly"-like conformation in the crystal. Both families of dyes show charge- or electron-transfer-type fluorescence-quenching characteristics in polar solvents when equipped with a strong donor in the meso-position of the core. These processes can be utilized for signaling purposes if an appropriate receptor is introduced. Further modification of the chromophore can invoke such a guest-responsive intramolecular quenching process, also for receptor groups of low electron density, for example, benzocrowns. In addition to the design of various prototype molecules, a promising fluoroionophore for Na+ was obtained that absorbs and emits in the 650 nm region and shows a strong fluorescence enhancement upon analyte binding. Furthermore, investigation of the remarkable solvatokinetic fluorescence properties of the "butterfly"-like bc-BDP derivatives suggested that a second intrinsic nonradiative deactivation channel can play a role in the photophysics of boron-dipyrromethene dyes.

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“…1 H NMR and 13 C NMR spectra were recorded in CDCl 3 on a JEOL EX 400 spectrometer at ambient temperature. NMR chemical shifts are expressed relative to TMS as the internal standard.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Boron–Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors—en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range

Shen

Röhr

Rurack

et al. 2004

Chemistry A European J

219

157

View full text Add to dashboard Cite

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“…Molecular orbital calculations were carried out using the CS-JNDO method described in detail elsewhere. 33 The INDO parameters (screening factors for the resonance integrals and one-center and two-center integrals) were taken from ref 34. The structural parameters of H1T used for the calculations are given in Figure 6.…”

Section: Analysis Of the Excited Statesmentioning

confidence: 99%

Triphenylene Columnar Liquid Crystals: Excited States and Energy Transfer

Markovitsi¹,

Germain²,

Millié³

et al. 1995

J. Phys. Chem.

171

200

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The present paper deals with the photophysical properties of columnar liquid crystals formed by hexakis-(alky1oxy)triphenylenes. Absorption and fluorescence spectra of solutions are analyzed on the basis of quantum chemical calculations performed by the CS-INDO-CI (conformations spectra-intermediate neglect of differential overlap-configuration interaction) m e t h d . the absorption maximum is due to the SO -Sq transition while fluorescence originates from the weak SO -S1 transition. In columnar aggregates, the former transition corresponds to delocalized excited states while the latter corresponds to localized ones; calculation of intermolecular interactions shows that, at the temperature domain of the mesophases, all the molecules have the same excitation energy and, therefore, no spectral diffusion of the fluorescence is expected, in agreement with the time-resolved emission spectra. Excitation transfer is investigated by studying the fluorescence decays of mesophases doped with energy traps. Their analysis is made by means of Monte Carlo simulations considering both intracolumnar and intercolumnar jumps and using four different models for the distance dependence of the hopping probability. The best description is obtained with a model based on the extended dipole approximation and taking into account molecular orientation.

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“…The parameters required by CS-INDO were taken from our earlier studies on conjugated molecules involving similar (second-order perturbation) CI treatments (20) and were used without any spkcial adjustment for carbenic systems. They are the screening factors k,, (= 1.0), kun (= 0.75), k,, (= 0.6) determining the values of the resonance integrals in a hybridized valence basis set; in addition, there &e n-type screening parameters (for the selection criterion of these parameters, see ref.…”

Section: Computational Techniquesmentioning

confidence: 99%

Conformational dependence of electronic spectra and zero-field splitting parameters in 2-naphthylphenylcarbene

Parisel¹,

Berthier²,

Migirdicyan³

1995

Can. J. Chem.

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Quantum mechanical calculations using ab initio and semi-empirical methods have been camed out for elucidating the electronic structure and geometry of 2-naphthylphenylcarbene conformers. The Zlcis conformer has the lowest ground state triplet energy, the lowest triplet-triplet (To-TI) transition energy, as well as the largest zero-field splitting parameter D. A clear-cut relationship between the D value and the geometry is pointed out.Key words: carbenes, conformational isomerism, triplet-triplet transitions, CS-INDOJCI calculations, ZFS D parameters.Resume : Dans le but dlCtudier la structure Clectronique et la gComCtrie du 2-naphtylphCnyle carbbne, des calculs de chimie quantique (ab initio et semi-empiriques) ont Ct C rCalisCs sur diffkrents conformbres de ce carbttne. Le calcul montre que c'est le conformkre Z k i s qui prksente 1'Cnergie minimale dans son Ctat triplet fondamental, 1'Cnergie de transition triplet-triplet (To-T,) la plus faible ainsi que la valeur la plus ClevCe du paramtttre D de sCparation des sous-niveaux triplets en champ nul. Une relation simple reliant D et la gComCtrie est mise en Cvidence.

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Theoretical study of trans-cis photoisomerism in polymethine cyanines

Cited by 113 publications

References 30 publications

Boron–Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors—en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range

Boron–Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors—en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range

Triphenylene Columnar Liquid Crystals: Excited States and Energy Transfer

Conformational dependence of electronic spectra and zero-field splitting parameters in 2-naphthylphenylcarbene

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