Charge Transfer Assisted by Collective Hydrogen‐Bonding Dynamics

Mohammed, Omar F.; Kwon, Oh‐Hoon; Othon, Christina M.; Zewail, Ahmed H.

doi:10.1002/ange.200902340

Cited by 9 publications

(13 citation statements)

References 44 publications

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“…This notion leads us to envision that the H‐bond network of alcohols should play an important role in their protonation reactivity to form the oxonium ion. Although various structural, energetic, and dynamic properties of H‐bond networks in alcohol have been studied, with and without excess protons, their possible participation during chemical reactions has not been paid enough attention …”

Section: Methodsmentioning

confidence: 99%

Alcohol Dimer is Requisite to Form an Alkyl Oxonium Ion in the Proton Transfer of a Strong (Photo)Acid to Alcohol

Park

Lee

Kwac

et al. 2016

Chemistry A European J

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What was the inspiration for this cover design? When we were invited to submit ac over suggestion, we were seeking an intuitive way to represent the key finding of this study: the basicity enhancement of an alcohol by hydrogen-bonded clustering. As such, we used at wo-pan balance, which "weighs" the basicity of ac lustered alcohol versus as ingle alcohol molecule, in the pk a scale, to highlight their difference. Is your current researchm ainly curiosity driven (fundamental) or rather applied? Our current research is basically curiosity driven. The role of the hydrogen bond network of water has been extensively investigated and, in many aspects, its importance can never be underestimated, in terms of structure, dynamics, and function in chemistry and biology .W eh ave also sought to understand how the hydrogen-bonded network of water is arranged and affects the energetics and dynamics of aqueous acid-base reactions by using photo-chemistry and photophysics. The motivation of this work, in particular ,w as the observation that the photoinduced proton transfer can also occur in alcohol with ap roperly chosen photoacid, yet this issue of proton transfer to alcohol is (perhaps surprisingly) poorly understood in the literature and textbooks, although this simple reaction is directly related to acid catalysis in alcohol dehydration , for example. Therefore, in this project, we were interested in understanding this very basic acid-base chemistry involving alcohol , which has not been considered in many organic chemistry textbooks. What other topics are you working on at the moment? Besides the current research in understanding the molecular mechanisms in acid-base reactions utilizing time-resolved spectroscopy, we are also very interested in studying structural dynamics in higher architectures made of small molecular entities, such as metal-organic frameworks and protein complexes. To this end, we are working on building ah igh-end time-resolved electron microscope at UNIST,w hich is now at the final phase of setting up. With the combination of electronic spectroscopy and structural imaging in space and time, we hope to extend our journey to understand various chemical and materials phenomena from am olecular level to amesoscopic level, where communication between constituents plays asignificant role in function. Invited for the cover of this issue is the group of Oh-Hoon Kwon at the Ulsan National Institute of Science and Technology and the Institutef or Basic Science in Ulsan. The image depicts at wo-pan balance representingt he enhancemento fa na lco-hol'sb asicity by hydrogen-bonded clustering, as investigatedb yt ime-resolved fluorescence quenching of as trong Brønsted photoacid. Read the full text of the article at

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Section: Methodsmentioning

confidence: 99%

Alcohol Dimer is Requisite to Form an Alkyl Oxonium Ion in the Proton Transfer of a Strong (Photo)Acid to Alcohol

Park

Lee

Kwac

et al. 2016

Chemistry A European J

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“…9(a), a slight band narrowing may be noticed over a short time range, suggesting that vibrational cooling may be an additional channel for the dissipation of excess vibrational energy. 49 All these processes may contribute to the reduction of the fluorescence intensity in methanol. In the normalized time-resolved emission spectra Fig.…”

Section: Time-resolved Spectroscopymentioning

confidence: 99%

Ultrafast excited state dynamics of trans-[4-(4′-dimethylaminostyryl)] pyridine N-oxide in solution: femtosecond fluorescence up-conversion and theoretical calculations

Szemik-Hojniak

Deperasińska

Oberda

et al. 2013

Phys. Chem. Chem. Phys.

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The results of the steady-state and time-resolved fluorescence-spectroscopy measurements and DFT calculations for trans-[4-(4'-dimethylaminostyryl)] pyridine N-oxide (trans-DPO) in various solvents are presented. These results are similar to those reported in the literature for trans-4-(dimethylamino)-4'-cyanostilbene (DCS) where the S1 emissive state shows the charge-transfer (CT) nature. Alcohol solvents, however, have aroused our particular interest because hydrogen-bonded complexes are formed between them and the trans-DPO molecule. They demonstrate a stronger CT character of the lower lying excited state and a larger separation between the first and the second absorption band than in the free trans-DPO molecule. The different effects found in time-dependent femtosecond up-conversion (performed for several emission wavelengths in dioxane and methanol solution over the time range 0-40 ps) were assigned to the hydrogen bond assisted charge transfer process in trans-DPO in methanol, to the excited-state solvation dynamics and mainly to solvent relaxation of trans-DPO dissolved in dioxane and methanol.

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“…Charge transfer from hydroxide to PBI is assisted by collective solvent hydrogen-bonding interactions and the delocalization of charges through the p surface of PBI; this has important implications both for solvation and local chemical reactions (such as enzyme catalysis). [21] The J aggregates of dihydroxyperylene bisimides with unusual spectroscopic properties are related to their twisted pconjugated core and self-complementary arrays of hydrogen-bond donors/acceptors. [15b, 22] UV/Vis absorption data supports the slipped p-p stacking interaction between the perylene cores according to exciton theory.…”

Section: Abstract In Chinesementioning

confidence: 99%

Synthesis and Self‐Assembly of Dihydroxyperylene Bisimides for the Tuning of Photophysical Properties

Qing

et al. 2012

Chemistry An Asian Journal

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The synthesis of 1,10-dihydroxyperylene bisimides by nucleophilic substitution of brominated perylene bisimide is described. 1,10-Dihydroxyperylene bisimides formed J aggregates in nonpolar solvents and showed a clearly redshifted absorption band. The solvent polarity also influenced the hydrogen bond with the hydroxyl group, and thus, the photophysical properties of perylene bisimide. The photophysical properties of these dihydroxyperylene perylene bisimides can also be tuned by changing charge transfer from the hydroxyl groups to the perylene core through the introduction of metal ions.

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Charge Transfer Assisted by Collective Hydrogen‐Bonding Dynamics

Cited by 9 publications

References 44 publications

Alcohol Dimer is Requisite to Form an Alkyl Oxonium Ion in the Proton Transfer of a Strong (Photo)Acid to Alcohol

Alcohol Dimer is Requisite to Form an Alkyl Oxonium Ion in the Proton Transfer of a Strong (Photo)Acid to Alcohol

Ultrafast excited state dynamics of trans-[4-(4′-dimethylaminostyryl)] pyridine N-oxide in solution: femtosecond fluorescence up-conversion and theoretical calculations

Synthesis and Self‐Assembly of Dihydroxyperylene Bisimides for the Tuning of Photophysical Properties

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