Assembling Structures of Diphenylalanine Linked with Dibenzoylmethanatoboron Difluoride Depending on the Solvent as Probed by Fluorescence Changes

2020 ◽  
Vol 49 (7) ◽  
pp. 802-805
Author(s):  
Shiho Katsumi ◽  
Takehiro Sagawa ◽  
Tsuyoshi Fukaminato ◽  
Fuyuki Ito
Keyword(s):  
Dibenzoylmethanatoboron Difluoride

The photocycloaddition of dibenzoylmethanatoboron difluoride (DBMBF2) with conjugated enones and en-esters

1993 ◽  
Vol 71 (6) ◽  
pp. 846-854 ◽  
Author(s):  
Yuan L. Chow ◽  
Shi-Sen Wang ◽  
Xian-En Cheng
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Ring Opening ◽  
Electron Donors ◽  
Head Orientation ◽  
Singlet Excited State ◽  
Methyl Substitution ◽  
Unsaturated Ketones ◽  
Dibenzoylmethanatoboron Difluoride

Dibenzoylmethanatoboron difluoride (DBMBF2), the BF2 complex of dibenzoylmethane, reacted from its singlet excited state with α,β-unsaturated ketones and esters to give 1,5-diketones by a [2+2] cycloaddition and ring-opening sequence in an analogous pathway to that observed in the photocycloaddition to olefins and dienes. The present photoreaction is unexpected since conjugated enones and en-esters are poor electron donors to comply with the previously proposed charge transfer requirement in DBMBF2 photoreactions. The photocycloaddition to these substrates was highly regioselective and stereoselective, giving the head-to-head orientation, which could be enhanced by α-methyl substitution; β-methyl substitution increased the alternate head-to-tail orientation. The photolysis of a mixture of DBMBF2 and a cyclic enone also caused the latter to dimerize to give head-to-head and head-to-tail dimers in significant yields. These photodimerizations were apparently caused by DBMBF2 sensitization. The mechanism of the sensitization is discussed.

Synthesis and Photophysical Properties of Alkoxysilyl Derivatives of Dibenzoylmethanatoboron Difluoride

2013 ◽  
Vol 24 (4) ◽  
pp. 271-282 ◽  
Author(s):  
Yuriy N. Kononevich ◽  
Ivan B. Meshkov ◽  
Natalia V. Voronina ◽  
Nikolay M. Surin ◽  
Viacheslav A. Sazhnikov ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Dibenzoylmethanatoboron Difluoride ◽  
Derivatives Of

Interaction of hydroxy substituted dibenzoylmethanatoboron difluoride with hydrated ammonia in solution: A combined spectroscopic and computational study

2019 ◽  
Vol 1175 ◽  
pp. 601-608 ◽  
Author(s):  
Natalia A. Gelfand ◽  
Elena V. Fedorenko ◽  
Anatoliy G. Mirochnik ◽  
Vitaliy I. Vovna
Keyword(s):  
Computational Study ◽  
Dibenzoylmethanatoboron Difluoride

Remote Activation of the Quadricyclane Group in a Quadricyclane−Steroid−{Dibenzoylmethanatoboron Difluoride} System by Intramolecular Electron Transfer†

2003 ◽  
Vol 107 (18) ◽  
pp. 3438-3442 ◽  
Author(s):  
Li-Ping Zhang ◽  
Bin Chen ◽  
Li-Zhu Wu ◽  
Chen-Ho Tung ◽  
Hong Cao ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Intramolecular Electron Transfer ◽  
Dibenzoylmethanatoboron Difluoride

Model of the formation of dibenzoylmethanatoboron difluoride exciplexes with aromatic hydrocarbons on silica surface

2015 ◽  
Vol 49 (3) ◽  
pp. 183-188 ◽  
Author(s):  
D. S. Ionov ◽  
V. A. Sazhnikov ◽  
G. A. Yurasik ◽  
A. V. Antonov ◽  
Yu. N. Kononevich ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Silica Surface ◽  
Dibenzoylmethanatoboron Difluoride

Solvent effects on photoreactions of dibenzoylmethanatoboron difluoride (DBMBF2) with cyclic dienes

1994 ◽  
Vol 35 (52) ◽  
pp. 9661-9664 ◽  
Author(s):  
Yuan L. Chow ◽  
Shi-Sen Wang
Keyword(s):  
Solvent Effects ◽  
Dibenzoylmethanatoboron Difluoride ◽  
Cyclic Dienes

Unusually strong emission from an exciplex formed between benzenoid solvents and dibenzoylmethanatoboron difluoride. Formation of a triplex

1995 ◽  
Vol 73 (11) ◽  
pp. 1902-1913 ◽  
Author(s):  
Pierre Valat ◽  
Véronique Wintgens ◽  
Yuan L. Chow ◽  
Jean Kossanyi
Keyword(s):  
Quantum Yield ◽  
Rate Constant ◽  
Fluorescence Quantum Yield ◽  
Equilibrium Constants ◽  
Back Reaction ◽  
Benzene Derivative ◽  
Exciplex Formation ◽  
Excited Complex ◽  
Low Concentrations ◽  
Dibenzoylmethanatoboron Difluoride

Benzene derivatives give, in cyclohexane solution, a strongly emitting (Φf up to 0.8) excited complex with dibenzoylmethanatoboron difluoride (DBMBF2). The rate constant kex for the complex formation varies between 3.5 × 109 and 2.6 × 1010 M−1 s−1 depending on the benzene derivative, and the complex emission can already be detected at very low concentrations of the aromatics. This behaviour is different from that found in acetonitrile where the DBMBF2 emission disappeared completely before the new emission of the complex could be detected. The position of the complex emission and its lifetime depend upon the redox potential of the aromatics: the lower the latter, the longer the lifetime and the more the emission is red-shifted. The monotonous increase of the lifetime and of the fluorescence quantum yield of the emission with the concentration of the aromatics has been interpreted on the basis of an equilibrium between the exciplex and excited DBMBF2. The equilibrium constant varies with the electron-donating property of the aromatics, from 2.7 for benzene to 560 M−1 for isodurene. A decrease in the excited complex lifetime or in its fluorescence quantum yield is observed in some cases when the aromatics concentration is close to that of the pure solvent. Such behaviour is believed to arise from a new equilibrium resulting from the interaction of the exciplex with a second molecule of the aromatics to form triplex species. A detailed kinetic study has been undertaken in case of p-xylene, and the rate constants of all the processes involved in the double equilibrium have been determined. No basic difference is observed in the rate constant for exciplex formation when a single or double equilibrium is assumed; on the other hand, large discrepancies are found in the exciplex deactivation processes, specially for the back reaction from the exciplex to excited DBMBF2. The equilibrium constants between DBMBF2 and the exciplex, on one hand, and between the latter and the triplex are 56.6 and 0.68 M−1, respectively, when the concentration of p-xylene in cyclohexane is 3.3 M. Keywords: fluorescence, exciplex, triplex, dibenzoylmethanatoboron difluoride, kinetics.

The Structure and Decay Dynamics of Exciplexes Derived from Dibenzoylmethanatoboron Difluoride and Alkylbenzenes in Cyclohexane

2000 ◽  
Vol 6 (16) ◽  
pp. 2942-2947 ◽  
Author(s):  
Yuan L. Chow ◽  
Zhong-Li Liu ◽  
C. Ingemer Johansson ◽  
Jun-ichi Ishiyama
Keyword(s):  
Dibenzoylmethanatoboron Difluoride

Cooperative effects of o- and m-methyl groups on the intramolecular charge-transfer emission properties of dibenzoylmethanatoboron difluorides

2017 ◽  
Vol 16 (6) ◽  
pp. 845-853 ◽  
Author(s):  
Mirai Tanaka ◽  
Shunsuke Muraoka ◽  
Yasunori Matsui ◽  
Eisuke Ohta ◽  
Takuya Ogaki ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Methyl Groups ◽  
Emission Properties ◽  
Cooperative Effects ◽  
Dibenzoylmethanatoboron Difluoride

Intramolecular charge-transfer character of the p-xylyl derivative of dibenzoylmethanatoboron difluoride is induced by o- and m-methyl groups cooperatively.

Vibronic bandshape of the absorption spectra of dibenzoylmethanatoboron difluoride derivatives: analysis based on ab initio calculations

2015 ◽  
Vol 17 (26) ◽  
pp. 16997-17006 ◽  
Author(s):  
Pavel S. Rukin ◽  
Alexandra Ya. Freidzon ◽  
Andrei V. Scherbinin ◽  
Vyacheslav A. Sazhnikov ◽  
Alexander A. Bagaturyants ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Absorption Spectra ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Time Dependent ◽  
Dibenzoylmethanatoboron Difluoride

The nature of absorption bandshapes of dibenzoylmethanatoboron difluoride (DBMBF2) derivatives is investigated using TDDFT and time-dependent linear vibronic coupling model.

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