scholarly journals A computational study on how structure influences the optical properties in model crystal structures of amyloid fibrils

2017 ◽  
Vol 19 (5) ◽  
pp. 4030-4040 ◽  
Author(s):  
Luca Grisanti ◽  
Dorothea Pinotsi ◽  
Ralph Gebauer ◽  
Gabriele S. Kaminski Schierle ◽  
Ali A. Hassanali
Keyword(s):  
Optical Properties ◽  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Crystal Structures ◽  
Amyloid Fibrils ◽  
Computational Study ◽  
Model Systems ◽  
Hydrogen Bonding Interactions ◽  
Model Crystal ◽  
Different Types

Different types of hydrogen bonding interactions that occur in amyloids model systems and molecular factors that control the susceptibility of the protons to undergo proton transfer and how this couples to the optical properties.

scholarly journals The Geometry of the Catalytic Active Site in [FeFe]-Hydrogenases is Determined by Hydrogen Bonding and Proton Transfer

2019 ◽  
Author(s):  
Jifu Duan ◽  
Stefan Mebs ◽  
Moritz Senger ◽  
Konstantin Laun ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Active Site ◽  
Time Resolved ◽  
X Ray Crystallography ◽  
Hydrogen Bonding Interactions ◽  
Catalytic Active Site ◽  
Catalytic Intermediates ◽  
Time Resolved Infrared Spectroscopy

The H2 conversion and CO inhibition reactivity of nine [FeFe]-hydrogenase constructs with semi-artificial cofactors was studied by in situ and time-resolved infrared spectroscopy, X-ray crystallography, and theoretical methods. Impaired hydrogen turnover and proton transfer as well as characteristic CO inhibition/ reactivation kinetics are assigned to varying degrees of hydrogen-bonding interactions at the active site. We show that the probability to adopt catalytic intermediates is modulated by intramolecular and protein-cofactor interactions that govern structural dynamics at the active site of [FeFe]-hydrogenases.<br>

scholarly journals The Geometry of the Catalytic Active Site in [FeFe]-Hydrogenases is Determined by Hydrogen Bonding and Proton Transfer

2019 ◽  
Author(s):  
Jifu Duan ◽  
Stefan Mebs ◽  
Moritz Senger ◽  
Konstantin Laun ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Active Site ◽  
Time Resolved ◽  
X Ray Crystallography ◽  
Hydrogen Bonding Interactions ◽  
Catalytic Active Site ◽  
Catalytic Intermediates ◽  
Time Resolved Infrared Spectroscopy

The H2 conversion and CO inhibition reactivity of nine [FeFe]-hydrogenase constructs with semi-artificial cofactors was studied by in situ and time-resolved infrared spectroscopy, X-ray crystallography, and theoretical methods. Impaired hydrogen turnover and proton transfer as well as characteristic CO inhibition/ reactivation kinetics are assigned to varying degrees of hydrogen-bonding interactions at the active site. We show that the probability to adopt catalytic intermediates is modulated by intramolecular and protein-cofactor interactions that govern structural dynamics at the active site of [FeFe]-hydrogenases.<br>

scholarly journals Recent Progress in Hydrogen-Bonded π-Conjugated Systems Displaying J-Type Aggregates

2020 ◽  
Vol 02 (01) ◽  
pp. 047-063 ◽  
Author(s):  
Nelson Ricardo Ávila-Rovelo ◽  
Amparo Ruiz-Carretero
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Noncovalent Interactions ◽  
Functional Materials ◽  
Organic Electronic Devices ◽  
Conjugated Systems ◽  
Hydrogen Bonding Interactions ◽  
Different Types ◽  
J Aggregates ◽  
Additional Hydrogen

Supramolecular approaches are of great interest in the design of functional materials. The types of aggregates arising from different noncovalent interactions endow materials with intriguing properties. In this sense, J-type aggregates are very attractive due to their unique optical properties and capacity to transport excitons. These features make them great candidates in the design of materials for organic electronic devices. Furthermore, the incorporation of additional hydrogen-bonding functionalities provides J-aggregates with superior directionality and connection among the different π-conjugated cores. The control over the formation of H-bonds to achieve functional aggregates is therefore a promising strategy towards controlled structures with specific functions.This review outlines the most relevant and recent works of π-conjugated systems exhibiting J-type aggregates resulting from hydrogen-bonding interactions. Different types of hydrogen-bonding functionalities will be discussed together with their roles in the aggregate properties, their impact in the optoelectronic properties, the self-assembly mechanisms, and their applications in organic electronics.

scholarly journals Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5853
Author(s):  
Sulejman Skoko ◽  
Matteo Ambrosetti ◽  
Tommaso Giovannini ◽  
Chiara Cappelli
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Force Field ◽  
Absorption Spectra ◽  
Computational Study ◽  
Md Simulations ◽  
Quantum Mechanical ◽  
Hydrogen Bonding Interactions

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.

scholarly journals Crystal structures ofN′-aminopyridine-2-carboximidamide andN′-{[1-(pyridin-2-yl)ethylidene]amino}pyridine-2-carboximidamide

2017 ◽  
Vol 73 (7) ◽  
pp. 1021-1025
Author(s):  
Francois Eya'ane Meva ◽  
Timothy John Prior ◽  
David John Evans ◽  
Emmanuel Roland Mang
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Dimensional Chain ◽  
Two Dimensional ◽  
One Dimensional ◽  
Bond Lengths ◽  
Hydrogen Bonding Interactions ◽  
Hydrogen Bonding Network

The crystal structures ofN′-aminopyridine-2-carboximidamide (C6H8N4),1, andN′-{[1-(pyridin-2-yl)ethylidene]amino}pyridine-2-carboximidamide (C13H13N5),2, are described. The non-H atoms in compound1are nearly planar (r.m.s. deviation from planarity = 0.0108 Å), while2is twisted about the central N—N bond by 17.8 (2)°. Both molecules are linked by intermolecular N—H...N hydrogen-bonding interactions;1forms a two-dimensional hydrogen-bonding network and for2the network is a one-dimensional chain. The bond lengths of these molecules are similar to those in other literature reports of azine and diimine systems.

scholarly journals Crystal Structures of Four Novel Thiophene/Phenyl-piperidine Hybrid Chalcones

2014 ◽  
Vol 70 (a1) ◽  
pp. C1020-C1020
Author(s):  
Masood Parvez ◽  
Muhammad Bakhtiar ◽  
Muhammad Baqir ◽  
Muhammad Zia-ur-Rehman
Keyword(s):  
Hydrogen Bonding ◽  
Pharmaceutical Industry ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Benzene Ring ◽  
Drug Targets ◽  
Important Class ◽  
Hydrogen Bonding Interactions ◽  
Benzene Rings ◽  
Type C

Chalcones constitute an important class of bioactive drug targets in the pharmaceutical industry that includes anti-ulcerative drug sofalcone. In continuation of our work, the crystal structures of four closely related 1-phenyl-piperidine based chalcones will be presented. I: C19 H21NOS, MW = 311.43, T = 173(2) K, λ = 0.71073 Å, Orthorhombic, P b c a, a = 10.1045(4), b = 10.5358(4), c = 30.6337(12) Å, V = 3261.2(2) Å3, Z = 8, Dc = 1.269 Mg/m3, F (000) = 1328, R [I>2σ(I)] = 0.059. II: C18H19NOS, MW = 297.40, T = 173(2) K, λ = 1.54178 Å, Orthorhombic, P b c a, a = 8.9236(2), b = 11.0227(2), c = 30.8168(6) Å, V = 3031.21(11) Å3 Z = 8, Dc = 1.303 Mg/m3, F (000) = 1264, R [I>2σ(I)] = 0.035. III: C18H19NOS, MW = 297.40, T = 173(2) K, λ = 1.54178 Å, Orthorhombic, P b c a, a = 8.82990(10), b = 11.0061(2), c = 31.2106(5) Å, V = 3033.13(8) Å3, Z = 8, Dc = 1.303 Mg/m3, F (000) = 1264, R [I>2σ(I)] = 0.048. IV: C18H18ClNOS, MW = 331.84, T = 173(2) K, λ = 0.71073 Å, Monoclinic, P 21/c, a = 14.1037(4), b = 11.3153(3), c = 10.1290(2) Å, β = 101.1367(14)0, V = 1586.02(7) Å3, Z = 4, Dc = 1.390 Mg/m3, F (000) = 696, R [I>2σ(I)] = 0.038. The crystals of I, II and III are isomorphous. In all structures, the piperidine rings are in chair conformations, thiophene rings are essentially planar and the C=C bonds in the prop-2-en-1-one fragment adopt E-conformation. All crystal structures are devoid of any classical hydrogen bonds. However, non-classical hydrogen bonding interactions of the type C---H...O in compounds II, III and IV link the molecules into chains extended along the b-axis. Moreover, C---H...Cg interactions involving thiophene rings in I and III and benzene ring in IV and π...π interactions between benzene rings lying about inversion centers are present in II and III.

Hydrogen-Bonding Interactions of (CF3)3CH and (CF3)3C−in the Gas Phase. An Experimental (FT-ICR) and Computational Study

2009 ◽  
Vol 113 (23) ◽  
pp. 6422-6429 ◽  
Author(s):  
Andrés Guerrero ◽  
Rebeca Herrero ◽  
Juan Z. Dávalos ◽  
Ivar Koppel ◽  
José-Luis M. Abboud ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Bonding Interactions ◽  
Ft Icr

Molecular Cocrystals of Carboxylic Acids. XXXII The Crystal Structures of the Adducts of 2-Aminobenzothiazole with 3,5-Dinitrobenzoic Acid (Adduct Hydrate) and 3-Aminobenzoic Acid, and 2-Amino-2-thiazoline with 2-Aminobenzoic Acid

1998 ◽  
Vol 51 (7) ◽  
pp. 587 ◽  
Author(s):  
Daniel E. Lynch ◽  
Graham Smith ◽  
Karl A. Byriel ◽  
Colin H. L. Kennard
Keyword(s):  
Optical Properties ◽  
Proton Transfer ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Second Order ◽  
Aminobenzoic Acid ◽  
Aromatic Carboxylic Acids ◽  
X Ray ◽  
Linear Optical Properties ◽  
Acid Adduct

Two adducts of 2-aminobenzothiazole and one of 2-amino-2-thiazoline with aromatic carboxylic acids have been synthesized and their X-ray crystal structures determined. These are 2-aminobenzothiazole with 3,5-dinitrobenzoic acid (the 1 : 1 adduct hydrate) (1), and 3-aminobenzoic acid (1 : 1) (2), and 2-amino-2-thiazoline with 2-aminobenzoic acid (1 : 1) (3). Compound (1) is a non-centrosymmetric proton-transfer complex and gave a signal of 0·30 relative to urea when tested for second-order non-linear optical properties. Compound (3) is also a proton-transfer complex but (2) is not.

scholarly journals Crystal structures of three complexes of zinc chloride with tri-tert-butylphosphane

2016 ◽  
Vol 72 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Aaron D. Finke ◽  
Danielle L. Gray ◽  
Jeffrey S. Moore
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Zinc Chloride ◽  
Chloride Complex ◽  
Lewis Base ◽  
Ambient Conditions ◽  
Hydrogen Bonding Interactions ◽  
Complex Forms ◽  
Cl Atoms

Under anhydrous conditions and in the absence of a Lewis-base solvent, a zinc chloride complex with tri-tert-butylphosphane as the μ-bridged dimer is formed,viz.di-μ-chlorido-bis[chloridobis(tri-tert-butylphosphane)zinc], [ZnCl4(C12H27P)2], (1), which features a nearly square-shaped (ZnCl)2cyclic core and whose Cl atoms interact weakly with C—H groups on the phosphane ligand. In the presence of THF, monomeric dichlorido(tetrahydrofuran-κO)(tri-tert-butylphosphane-κP)zinc, [ZnCl2(C4H8O)(C12H27P)] or [P(tBu3)(THF)ZnCl2], (2), is formed. This slightly distorted tetrahedral Zn complex has weak C—H...Cl interactions between the Cl atoms and phosphane and THF C—H groups. Under ambient conditions, the hydrolysed complex tri-tert-butylphosphonium aquatrichloridozincate 1,2-dichloroethane monosolvate, (C12H28P)[ZnCl3(H2O)]·C2H4Cl2or [HPtBu3]+[(H2O)ZnCl3]−·C2H4Cl2, (3), is formed. This complex forms chains of [(H2O)ZnCl3]−anions from hydrogen-bonding interactions between the water H atoms and Cl atoms that propagate along thebaxis.

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