Dynamics of transfer of electron excitation in a donor-acceptor system with a carbon chain and ways of its relaxation

Sevryukova, M. M.

doi:10.15407/spqeo20.04.406

Cited by 1 publication

(4 citation statements)

References 25 publications

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“…But in Fig. 5 a, b it is shown that the PL depends on polarity even at 4.2 K [8].The common for both solvents is short-wave shift of the PL bands maxima at low temperature compared to bands maxima at room temperature.…”

Section: Optical Properties Of M-1 and M-2 Molecules In Toluenementioning

confidence: 83%

“…The bands in PL spectra with 450 are caused by the electronic transitions from the local electronic states of dimethylamino group. The PL bands with 450 are necessitated by first singlet π electronic transition that strongly depends on a carbon chain conformation [8]. The absorption spectral bands with 498 and 545…”

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

“…3 is equal to 182 (5374 ). An investigation of solution M-2 in acetonitrile was described in paper [8]. Fig.…”

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

“…The PL lifetimes of different wavelength were determined from PL decay curves and are shown in Table 1. The date set of M-2 was kindly provided by authors of article [8]. 405 .…”

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

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Fluorescence of molecular composites that consist of nematic liquid crystal and merocyanins

2020

Biophysical Bulletin

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Background: Considered merocyanine molecules have donor D and acceptor A moieties connected by polymer chain. The conjugated donor D and acceptor A parts of merocyanine molecules are planar in the ground state. The D-π-A molecular complexes can change their conformations in an excited state due to cis-trans-conformational transitions. The viscosity of the solvent affects conformational changes, photoluminescence (PL) decay and PL lifetime. Therefore the PL of merocyanine molecules strongly depends on medium in excited and ground states. A nematic liquid crystal was utilized as a solvent for merocyanine molecules since it is characterized by long range order, orientates merocyanine molecules along its axis and is sensitive to external electro-magnetic field. The molecules with conjugated donor D and acceptor A parts are promising for molecular electronics (instruments for recording and processing information), optoelectronics (laser technologies) and biological research (fluorescent probes like prominent thioflavin T), since their PL essentially depends on the nature of the environment. Objectives: The main objective of this paper is to investigate and explain impact of liquid crystal medium on considered molecules. Also influence of molecular conformational changes on their spectral properties is considered. Materials and Methods: Two types of merocyanine molecules M-1 and M-2 were investigated. The spectral properties of molecules in different organic solvents such as acetonitrile, toluene, glycerol, and in 4-pentyl-4′-cyanobiphenyl (5CB) liquid crystal were compared. Stationary and time-resolved emission spectra of molecular merocyanine solutions were used to investigate conformational changes of molecules. To determine a lifetime of molecular excited states, a technique of Time Correlated Single Photon Counting with picosecond resolution in time was used. Results: The results indicate that optical properties strongly depend on conformation of conjugated donor-π-acceptor compounds. A relaxation of dye molecules to the ground state is accompanied by conformational changes. The quantum yield and lifetime of PL increase in more viscous solvents. The liquid crystal made conformational changes of considered molecules in ground and excited states. Conclusions: Analysis of the results serves as a basis for constructing a theory that explains properties of D-π-A molecular compounds under optical excitation. The molecular pairs are formed by merocyanine and liquid crystal molecules. The liquid crystal molecule defines conformation of merocyanine molecule in a pair. Moreover, both types of merocyanine molecules in liquid crystal have the same conformation. This hypothesis explains similarities of optical properties of M-1 and M-2 molecules in liquid crystal.

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Section: Optical Properties Of M-1 and M-2 Molecules In Toluenementioning

confidence: 83%

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

“…3 is equal to 182 (5374 ). An investigation of solution M-2 in acetonitrile was described in paper [8]. Fig.…”

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

“…The PL lifetimes of different wavelength were determined from PL decay curves and are shown in Table 1. The date set of M-2 was kindly provided by authors of article [8]. 405 .…”

Section: Optical Properties Of M-1 and M-2 Molecules In Acetonitrilementioning

confidence: 99%

See 2 more Smart Citations

Fluorescence of molecular composites that consist of nematic liquid crystal and merocyanins

2020

Biophysical Bulletin

View full text Add to dashboard Cite

show abstract

Dynamics of transfer of electron excitation in a donor-acceptor system with a carbon chain and ways of its relaxation

Cited by 1 publication

References 25 publications

Fluorescence of molecular composites that consist of nematic liquid crystal and merocyanins

Fluorescence of molecular composites that consist of nematic liquid crystal and merocyanins

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