Solvent effect on the conformation of Benzil

Pawełka, Z.; Koll, A.; Zeegers‐Huyskens, Th.

doi:10.1016/s0022-2860(01)00593-2

Cited by 22 publications

(19 citation statements)

References 39 publications

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“…However, recent investigations of the parent benzil structure (RH in Fig. 1) have indicated that benzil in various solvents exists in a single skewed conformation [21]. Preliminary electronic structure optimisations starting from the ''syn'' and ''anti'' conformations of b BPM point to two skewed conformations which actually appear to be quite similar.…”

Section: Methodsmentioning

confidence: 89%

Investigation of molecular dimers by ensemble and single molecule spectroscopy

Christ

Petzke

Bordat

et al. 2002

Journal of Luminescence

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Investigation of molecular dimers by ensemble and single molecule spectroscopy Christ, Th.; Petzke, F.; Bordat, P.; Herrmann, Andreas; Reuther, E.; Müllen, K.; Basché, Th. Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Christ, T., Petzke, F., Bordat, P., Herrmann, A., Reuther, E., Müllen, K., & Basché, T. (2002). Investigation of molecular dimers by ensemble and single molecule spectroscopy. Journal of Luminescence, 98, 23-33. CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractWe have investigated molecular dimers with different electronic coupling strengths by bulk and single molecule spectroscopy. In one of the dimers the two monomers (perylene-monoimide) are directly connected via a single bond while in the other one they are separated by the benzil motif. The close proximity of the monomers in the first case gives rise to excitonic band splitting which is clearly observable in the bulk absorption spectra. For the benzil structure the electronic interactions are governed by F .orster-type energy hopping between the monomers. Fluorescence intensity trajectories at the single molecule level show one-step and two-step bleaching behaviour which appears to be very similar for both dimers. However, emission spectra recorded simultaneously with the trajectories indicate spectral changes which allow to distinguish between weakly and strongly coupled dimers. In the latter case the spectral shape changes significantly when excitonic coupling has been lifted because of photochemical transformation of one of the monomers. r

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Section: Methodsmentioning

confidence: 89%

Investigation of molecular dimers by ensemble and single molecule spectroscopy

Christ

Petzke

Bordat

et al. 2002

Journal of Luminescence

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“…80°, in agreement with results of previously reported semiempirical calculations. 6,30 In a different experiment, irradiation of the matrix-isolated benzil was performed (λ > 235 nm). The results are summarized in Figure 8.…”

Section: Resultsmentioning

confidence: 99%

Matrix-Isolation FTIR Spectroscopy of Benzil: Probing the Flexibility of the C−C Torsional Coordinate

et al. 2004

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The infrared spectrum and conformational flexibility of benzil, (C 6 H 5 CO) 2 , are studied by matrix-isolation FTIR spectroscopy, supported by DFT calculations. It is shown that the low-frequency (ca. 25 cm -1 ), largeamplitude torsion around the C-C central bond strongly affects the structural and spectroscopic properties exhibited by the compound. The equilibrium conformational distribution of molecules with different OdC-CdO dihedral angles, existing at room temperature in the gas phase, and trapped in a low-temperature (T ) 9 K) inert matrix can be changed either by in situ irradiation with UV light (λ > 235 nm) or by annealing the matrix to higher temperatures (T ≈ 34 K). In the first case, the increase of the average OdC-CdO angle results from conformational relaxation in the excited electronic states (S 1 and T 1 ), whose lowest-energy conformations correspond, for both S 1 and T 1 states, to a nearly planar configuration with the OdC-CdO dihedral angle equal to 180°. In the second case, the decrease of the average value of the OdC-CdO dihedral angle is a consequence of the change in the S o C-C torsional potential, resulting from interactions with the matrix media, which favors the stability of the more polar structures with smaller OdC-CdO dihedral angles.

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“…[7][8][9][10][11][12] Since the intercarbonyl torsion angle (O=C-C=O) of benzil is an important parameter in rationalizing the geometry and the spectral properties of the molecule, x-ray diffraction study and few quantum chemical calculations are reported to determine the ground state geometry of the molecule. 5,[13][14][15][16] The x-ray study infers the angle to be about 72 • , while different computational methods report a wide range for the torsion angle from 109 • to 157 • .…”

Section: Introductionmentioning

confidence: 99%

“…[14][15][16] A great deal of study has been oriented toward the phosphorescence, both in frozen and molten maa) Author to whom correspondence should be addressed. Electronic mail:…”

Section: Introductionmentioning

confidence: 99%

Multiple emissions of benzil at room temperature and 77 K and their assignments from ab initio quantum chemical calculations

Bhattacharya

Jana

Bose

et al. 2011

The Journal of Chemical Physics

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Multiple emissions have been observed from benzil under different conditions in solutions at room temperature as well as in low temperature glass matrices at 77 K. Low temperature emission has been monitored in rigid matrices frozen under different conditions of illumination. Steady state and time-resolved results together with the ab initio quantum chemical calculations provide, for the first time, the assignments of the different fluorescence bands to the different geometries and∕or electronic states of the fluorophore molecule. It is revealed that the skew form of benzil emits from the first (S(1)) as well as the second excited singlet (S(2)) states depending on the excitation wavelength, while the relaxed transplanar conformer fluoresces only from the S(1) state. The yet unexplored emission band peaking at around 360 nm has been assigned to originate from the S(2) state. Ab initio calculations using the density functional theory at B3LYP∕6-31G∗∗ level corroborate well with the experimental observations.

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Solvent effect on the conformation of Benzil

Cited by 22 publications

References 39 publications

Investigation of molecular dimers by ensemble and single molecule spectroscopy

Investigation of molecular dimers by ensemble and single molecule spectroscopy

Matrix-Isolation FTIR Spectroscopy of Benzil: Probing the Flexibility of the C−C Torsional Coordinate

Multiple emissions of benzil at room temperature and 77 K and their assignments from ab initio quantum chemical calculations

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