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Мирочник, А. Г.; Буквецкий, Б. В.; Gukhman, E. V.; Zhikhareva, P. A.; Карасев, В. Е.

doi:10.1023/a:1013086518794

Cited by 41 publications

(22 citation statements)

References 3 publications

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“…2, the band with a maximum at 500 nm is due to excimer fluorescence in concentrated solutions of di benzoyl methanate 1. 5 The band with a maximum at 470 nm coincides with the long wave band in the fluores cence spectrum of a solution with a low concentration of compound 1. According to published data, 9 the absence of two other fluorescence bands of single molecules (420 and 444 nm) from the spectrum of the crystals can be due to the fact that solutions of 1 contain rotamers with different positions of the Ph rings relatively to the plane of the diketonate cycle (Scheme 1).…”

Section: Resultsmentioning

confidence: 80%

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride

et al. 2005

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Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride was found. A substantial hypsochromic shift of the luminescence band maximum (60 nm) with a temperature decrease from 300 to 77 K was observed, and the luminescence color changed from green to blue. A considerable decrease (by 0.386 Å) in the unit cell parameters along the c axis was detected by X ray diffractometry when the temperature of the crystal decreased from 293 to 123 K. Shortening of the distances between the planes of adjacent molecules (stacking factor) weakens the interaction between the dimers and enhances the monomeric and excimeric luminescence.Development and synthesis of reversible luminescent thermochromes are urgent from both practical and theo retical standpoints. 1,2 One of the promising lines of search for new luminescent thermochromes is a study of mo lecular organized organic systems, including dimers, tri mers, and aggregates of conjugated molecules, whose supramolecular architecture produces different intermo lecular interactions: dimeric (excimeric), interdimeric, and stacking interactions. 3,4Continuing our works on studying the interrelation of the structure and luminescence and photochemical prop erties of boron difluoride β diketonates, 5-7 in this work we studied a change in the luminescence of dibenzo yl(methanato)boron difluoride (1) at different tempera tures and revealed reversible luminescence thermo chromism of this compound, namely, a substantial hypso chromic shift of the fluorescence band maximum (60 nm) and a change in the luminescence color from green to blue when the temperature decreases from 300 to 77 K. ExperimentalCompound 1 was synthesized according to a previously pub lished procedure. 8 Crystals were prepared by recrystallization from an acetonitrile-toluene (1 : 1) mixture. Fluorescence spec tra of solutions were obtained on a Shimadzu RF 5000 in strument. Luminescence spectra of crystalline compounds at 77-300 K were recorded on an SDL 1 spectrometer, using a DRSh 250 lamp as an excitation source and an UFS 6 filter (λ exc = 365 nm). To measure a temperature dependence of the luminescence spectra, a sample was placed in a quartz Dewar flask above the liquid nitrogen surface. The temperature of the sample was measured by a platinum thermocouple. The X ray diffraction study of compound 1 was carried out at 293, 203, and 123 K in a SMART 1000 CCD Bruker system using Мо Кα radiation. Results and DiscussionAs can be seen from the data in Fig. 1, a decrease in the temperature of the crystal from 300 to 77 K produces a substantial hypsochromic shift of the fluorescence band maximum of compound 1 (60 nm). For a more detailed analysis of the evolution of the luminescence spectra with a temperature change, the spectra were deconvoluted by the Gaussian expansion using the Origin 6.1 program; the results of deconvolution are presented in Fig. 1.It turned out that the fluorescence spectrum of com pound 1 at each temperature consists of three compo nents with maxima at 470, 500, and 560 nm, and o...

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Section: Resultsmentioning

confidence: 80%

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride

et al. 2005

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“…Unlike respective 1,3-dicarbonyl compounds, b-diketoboron difluorides shows an intensive luminescence both in solutions and in crystals [3]. This class of compounds is characterized by excimer luminescence observable as in solutions and as in crystals [4,5], moreover, luminescent thermochromism and size-dependent luminescence were observed in some crystals [6][7][8]. The optic properties of b-diketonatoboron difluorides crystals are closely connected with their molecular architecture [5,9].…”

Section: Introductionmentioning

confidence: 96%

“…This class of compounds is characterized by excimer luminescence observable as in solutions and as in crystals [4,5], moreover, luminescent thermochromism and size-dependent luminescence were observed in some crystals [6][7][8]. The optic properties of b-diketonatoboron difluorides crystals are closely connected with their molecular architecture [5,9]. One of the promising lines of search for new perspective luminescent materials is a study of molecular organised organic systems, including dimers, trimers, and aggregates of conjugated molecules, whose supramolecular architecture produces different intermolecular interactions: dimeric (excimeric), interdimeric, and p-stacking interactions [10,11].…”

Section: Introductionmentioning

confidence: 99%

Reversible luminescence thermochromism and phase transition in crystals of thiophenylacetylacetonatoboron difluoride

Мирочник

Федоренко

Kaidalova

et al. 2008

Journal of Luminescence

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“…11 The spec tra of microcrystals of 1 (d = 1-3 and 10 μm) exhibit a band with a maximum at 535 nm, which corresponds to fluorescence of excimers. 16 An interesting feature is the difference between the fluorescence spectra of the bulk crystals grown in solution (d = 500 μm) and in the poly mer matrix (see Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

Size-dependent luminescence of boron difluoride β-diketonates

2008

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Size dependent luminescence properties of boron difluoride β diketonates were detected. Most compounds investigated are characterized by noticeable hypsochromic shifts of luminescence band maxima on going from bulk crystals to microcrystals. However, a decrease in the crystal size of (dibenzoylmethanato)boron difluoride with unique supramolecular structure was accompanied by a bathochromic shift of the luminescence band maximum. Size dependent luminescence proper ties of complexes examined were analyzed in the framework of excitonic mechanism.

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Cited by 41 publications

References 3 publications

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride

Reversible luminescence thermochromism and phase transition in crystals of thiophenylacetylacetonatoboron difluoride

Size-dependent luminescence of boron difluoride β-diketonates

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