Electronic transitions in polymethine dyes involving local and delocalized levels

Viniychuk, O.O.; Levchenko, Svitlana M.; Przhonska, Olga V.; Kachkovsky, O.D.; Bricks, Yu.L.; Kudinova, M. A.; Kovtun, Yu. P.; Poronik, Ye.M.; Shandura, Mykola P.; Tolmachev, O.I.

doi:10.1016/j.molstruc.2013.12.038

Cited by 6 publications

(13 citation statements)

References 16 publications

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“…A C C E P T E D ACCEPTED MANUSCRIPT 26 It was established that the local levels are less sensitive to the lengthening of the polymethine chain than donor or delocalized levels [136,159]. So, the spectral band corresponding to the local transitions in the vinylene series of the pyrylocyanines 30, R = Ph was found by M.A.…”

Section: A N U S C R I P Tmentioning

confidence: 98%

“…The simple scheme of the donor/acceptor orbitals split in the polymethine dyes can be additionally complicated by the occurrence of specific MOs located only within TGs [136].…”

Section: Local Orbitals and Local Transitionsmentioning

confidence: 99%

“…So, the highest occupied MOs of the terminal residues in the cationic dyes can be treated as a donor orbital; at the same time, the lowest vacant MO of the TG in the anionic PMDs can be considered as an acceptor orbital [133][134][135][136]. Because of the different sensitivities of the donor/acceptor levels and levels produced by the polymethine chain to the total charge, the donor level could occur higher than the highest occupied levels of the chain in cationic dyes, while the acceptor level could be disposed below than the lowest vacant level produced by the chain.…”

Section: Introduction Of π π π π-Donor Substituents To Terminal Groupsmentioning

confidence: 99%

“…In the non-planar conformation without any conjugation, the frontier and nearest π-MOs (see Figure 4b) are located in the separate molecular fragments (although some MOs can involve the σ-orbitals, It was established that the HOMOs in the typical Brooker's cyanines 6-8 are generated mainly by terminal groups and hence they should be treated as donor orbitals [133][134][135][136]. Such a nature of the frontier level points clearly the first electron transition to be connected mainly with all molecular fragments, not only with the polymethine chain.…”

Section: Introduction Of π π π π-Donor Substituents To Terminal Groupsmentioning

confidence: 99%

“…Bricks et al for polymethine dyes derivatives of pyrroloantrone 25[131,132] and 2-azaazulene 26[133][134][135][136]. Absorption spectra of the first three vinylogous of dye 26 are presented inFigure 2.…”

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confidence: 99%

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Molecular design of near infrared polymethine dyes: A review

et al. 2015

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Section: A N U S C R I P Tmentioning

confidence: 98%

“…The simple scheme of the donor/acceptor orbitals split in the polymethine dyes can be additionally complicated by the occurrence of specific MOs located only within TGs [136].…”

Section: Local Orbitals and Local Transitionsmentioning

confidence: 99%

Section: Introduction Of π π π π-Donor Substituents To Terminal Groupsmentioning

confidence: 99%

Section: Introduction Of π π π π-Donor Substituents To Terminal Groupsmentioning

confidence: 99%

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confidence: 99%

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Molecular design of near infrared polymethine dyes: A review

et al. 2015

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Design and Electronic Structure of New Styryl Dye Bases: Steady-State and Time-Resolved Spectroscopic Studies

Башмакова

Levchenko

Masunov³

et al. 2014

J. Phys. Chem. A

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A comprehensive investigation of the electronic structure and fast relaxation processes in the excited states of new styryl base-type derivatives was performed using steady-state, pico-, and femtosecond time-resolved spectroscopic techniques. Linear photophysical parameters of new compounds, including steady-state absorption, fluorescence, and excitation anisotropy spectra, were obtained in a number of organic solvents at room temperature. A detailed analysis of the fluorescence lifetimes and ultrafast relaxation processes in the electronically excited state of the styryl bases revealed an important role of solvate dynamics and donor-acceptor strength of the molecular structures in the formation of their excited state absorption spectra. Experimental data were in good agreement with quantum chemical calculations at the time dependent density functional theory level, combined with a polarizable continuum model.

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Suppression of Kasha’s rule in higher excited states of 4-pyrilocyanines

Piryatinskiĭ

Verbitsky

Lutsyk

et al. 2018

Molecular Crystals and Liquid Crystals

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Spectral properties of the series of cationic polymethine dyes containing conjugated chain of different length and 4-pyrylium terminal groups were studied in details. Besides, the steadystate long-wavelength fluorescence from the lowest excited state and the fluorescence from higher excited states were experimentally revealed. The steady-state fluorescence band from the lowest excited state is shifted bathochromically with lengthening of the polymethine chain, which is also reflected in the absorption shift. According to quantum-chemical modeling, the appearance of unconventional fluorescence, which suppresses Kasha's rule, is associated with the different nature of the lowest excited states: the first and forth transitions are typical polymethine electron transitions involved only totally delocalized molecular orbitals (MOs), whereas the second and third transitions correspond to the electron jumping from the degenerated MOs localized only within the terminal groups (so called quasi-local MOs and hence quasi-local transitions). The forbidden transitions between the excited states of different types stimulate the fluorescence from the higher excited states.

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Electronic transitions in polymethine dyes involving local and delocalized levels

Cited by 6 publications

References 16 publications

Molecular design of near infrared polymethine dyes: A review

Molecular design of near infrared polymethine dyes: A review

Design and Electronic Structure of New Styryl Dye Bases: Steady-State and Time-Resolved Spectroscopic Studies

Suppression of Kasha’s rule in higher excited states of 4-pyrilocyanines

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