scholarly journals Modeling of the Response of Hydrogen Bond Properties on an External Electric Field: Geometry, NMR Chemical Shift, Spin-Spin Scalar Coupling

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4967
Author(s):  
Ilya G. Shenderovich ◽  
Gleb S. Denisov
Keyword(s):  
Hydrogen Bond ◽  
Electric Field ◽  
External Electric Field ◽  
Scalar Coupling ◽  
Wide Field ◽  
Field Range ◽  
Molecular Systems ◽  
Spectral Changes ◽  
Field Geometry ◽  
Δ 15N

The response of the geometric and NMR properties of molecular systems to an external electric field has been studied theoretically in a wide field range. It has been shown that this adduct under field approach can be used to model the geometric and spectral changes experienced by molecular systems in polar media if the system in question has one and only one bond, the polarizability of which significantly exceeds the polarizability of other bonds. If this requirement is met, then it becomes possible to model even extreme cases, for example, proton dissociation in hydrogen halides. This requirement is fulfilled for many complexes with one hydrogen bond. For such complexes, this approach can be used to facilitate a detailed analysis of spectral changes associated with geometric changes in the hydrogen bond. For example, in hydrogen-bonded complexes of isocyanide C≡15N-1H⋯X, 1J(15N1H) depends exclusively on the N-H distance, while δ(15N) is also slightly influenced by the nature of X.

scholarly journals Unusual Spectroscopic and Electric Field Sensitivity of a Chromophore with Short Hydrogen Bond: GFP and PYP as Model Systems

2020 ◽  
Author(s):  
Chi-Yun Lin ◽  
Steven Boxer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Electric Field ◽  
External Electric Field ◽  
Heavy Atom ◽  
Model Systems ◽  
Donor And Acceptor ◽  
Short Hydrogen Bond ◽  
Structural Methods ◽  
Short Hydrogen Bonds

<p> Short hydrogen bonds, with heavy-atom distances less than 2.7 Å, are believed to exhibit proton delocalization and their possible role in catalysis has been widely debated. While spectroscopic and/or structural methods are usually employed to study the degree of proton delocalization, ambiguities still arise and no direct information on the corresponding potential energy surface is obtained. Here we apply an external electric field to perturb the short hydrogen bond(s) within a collection of green fluorescent protein S65T/H148D variants and photoactive yellow protein mutants, where the chromophore participates in the short hydrogen bond(s) and serves as an optical probe of the proton position. As the proton is charged, its position may shift in response to the external electric field, and the chromophore’s electronic absorption can thus reflect the ease of proton transfer. The results suggest that low-barrier hydrogen bonds are not present within these proteins even when proton affinities between donor and acceptor are closely matched. Exploiting the chromophores as pre-calibrated electrostatic probes, the covalency of short hydrogen bonds as a non-electrostatic component was also revealed. No clear evidence was found for a possible contribution of unusually large polarizabilities of short hydrogen bonds due to proton delocalization; a theoretical framework for this interesting phenomenon is developed.<br></p>

scholarly journals Unusual Spectroscopic and Electric Field Sensitivity of a Chromophore with Short Hydrogen Bond: GFP and PYP as Model Systems

2020 ◽  
Author(s):  
Chi-Yun Lin ◽  
Steven Boxer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Electric Field ◽  
External Electric Field ◽  
Heavy Atom ◽  
Model Systems ◽  
Donor And Acceptor ◽  
Short Hydrogen Bond ◽  
Structural Methods ◽  
Short Hydrogen Bonds

<p> Short hydrogen bonds, with heavy-atom distances less than 2.7 Å, are believed to exhibit proton delocalization and their possible role in catalysis has been widely debated. While spectroscopic and/or structural methods are usually employed to study the degree of proton delocalization, ambiguities still arise and no direct information on the corresponding potential energy surface is obtained. Here we apply an external electric field to perturb the short hydrogen bond(s) within a collection of green fluorescent protein S65T/H148D variants and photoactive yellow protein mutants, where the chromophore participates in the short hydrogen bond(s) and serves as an optical probe of the proton position. As the proton is charged, its position may shift in response to the external electric field, and the chromophore’s electronic absorption can thus reflect the ease of proton transfer. The results suggest that low-barrier hydrogen bonds are not present within these proteins even when proton affinities between donor and acceptor are closely matched. Exploiting the chromophores as pre-calibrated electrostatic probes, the covalency of short hydrogen bonds as a non-electrostatic component was also revealed. No clear evidence was found for a possible contribution of unusually large polarizabilities of short hydrogen bonds due to proton delocalization; a theoretical framework for this interesting phenomenon is developed.<br></p>

Time-resolved X-ray reciprocal space mapping of the crystal under external electric field

2018 ◽  
Vol 189 (02) ◽  
pp. 187-194 ◽  
Author(s):  
Nikita V. Marchenkov ◽  
Anton G. Kulikov ◽  
Ivan I. Atknin ◽  
Arsen A. Petrenko ◽  
Alexander E. Blagov ◽  
...  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
Time Resolved ◽  
X Ray

2D Few Cycle Optical Pulses in Silicene in the Presence of External Electric Field

2017 ◽  
Vol 9 (3) ◽  
pp. 03044-1-03044-3
Author(s):  
M. B. Belonenko ◽  
◽  
N. N. Konobeeva ◽  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Optical Pulses

Density Functional Theory Study of Antioxidant Adsorption onto Single- Wall Boron Nitride Nanotubes: Design of New Antioxidant Delivery Systems

2019 ◽  
Vol 22 (7) ◽  
pp. 470-482
Author(s):  
Samereh Ghazanfary ◽  
Fatemeh Oroojalian ◽  
Rezvan Yazdian-Robati ◽  
Mehdi Dadmehr ◽  
Amirhossein Sahebkar
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Vitamin C ◽  
Electric Field ◽  
External Electric Field ◽  
Lipoic Acid ◽  
Density Functional ◽  
Cell Interaction ◽  
Boron Nitride Nanotubes ◽  
Functional Theory

Background: Boron Nitride Nanotubes (BNNTs) have recently emerged as an interesting field of study, because they could be used for the realization of developed, integrated and compact nanostructures to be formulated. BNNTs with similar surface morphology, alternating B and N atoms completely substitute for C atoms in a graphitic-like sheet with nearly no alterations in atomic spacing, with uniformity in dispersion in the solution, and readily applicable in biomedical applications with no obvious toxicity. Also demonstrating a good cell interaction and cell targeting. Aim and Objective: With a purpose of increasing the field of BNNT for drug delivery, a theoretical investigation of the interaction of Melatonin, Vitamin C, Glutathione and lipoic acid antioxidants using (9, 0) zigzag BNNTs is shown using density functional theory. Methods: The geometries corresponding to Melatonin, Vitamin C, Glutathione and lipoic acid and BNNT with different lengths were individually optimized with the DMOL3 program at the LDA/ DNP (fine) level of theory. Results: In the presence of external electric field Melatonin, Vitamin C, Glutathione and lipoic acid could be absorbed considerably on BNNT with lengths 22 and 29 Å, as the adsorption energy values in the presence of external electric field are considerably increased. Conclusion: The external electric field is an appropriate technique for adsorbing and storing antioxidants on BNNTs. Moreover, it is believed that applying the external electric field may be a proper method for controlling release rate of drugs.

Structure and Reactivity of Selected Pyrimidine and Purine Bases in the External Electric Field

2019 ◽  
Vol 8 (4) ◽  
pp. 263-278
Author(s):  
Józef Mazurkiewicz ◽  
Piotr Tomasik ◽  
Wojciech Ciesielski
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Purine Bases

Photodiodes based on MAPbBr3/Bi3+ doped MAPbCl3 single crystals heterojunction for X-ray detection

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yuzhu Pan ◽  
Xin Wang ◽  
Jingda Zhao ◽  
Yubing Xu ◽  
Yuwei Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Single Crystals ◽  
External Electric Field ◽  
High Performance ◽  
X Ray

Perovskites single crystals (PSCs) could be used to made high performance photoelectric detectors due to its superior optoelectronic characteristics. Generally, external electric field need to be applied in the PSCs-based...

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