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Molecule
About: Molecule is a research topic. Over the lifetime, 52462 publications have been published within this topic receiving 1234914 citations.
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TL;DR: In the title compound, C5H14N3+·H2PO4−, the cation has a central guanidinium fragment with a planar geometry, as expected for a central Csp2 atom with a small charge delocalization along the three C—N bonds.
Abstract: In the title compound, C5H14N3+·H2PO4−, the cation has a central guanidinium fragment with a planar geometry, as expected for a central Csp2 atom with a small charge delocalization along the three C—N bonds. The crystal packing is governed by hydrogen bonds so that the phosphate anions are linked head to tail, forming chains running parallel to the c direction. These chains in turn are interconnected by hydrogen bonds to intermediate tetramethylguanidinium cations forming hydrogen-bonded molecular layers stacked parallel to the bc crystal planes.
30 citations
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TL;DR: It is found that the nature of interaction between various atoms of glycine molecules, as characterized by radial distribution functions, can provide interesting insight into the formation of hydrogen bonds that in turn affect the diffusion coefficients at the interface.
Abstract: Glycine is an amino acid that has several applications in the pharmaceutical industry Hence, growth of alpha-glycine crystals through solution crystallization is an important process To gain a fundamental understanding of the seeded growth of alpha-glycine from aqueous solution, the (110) face of alpha-glycine crystal in contact with a solution of glycine in water has been simulated with molecular dynamics The temporal change in the location of the interface of the alpha-glycine crystal seed has been characterized by detecting a density gradient It is found that the alpha-glycine crystal dissolves with time at a progressively decreasing rate Diffusion coefficients of glycine adjacent to (110) face of alpha-glycine crystal have been calculated at various temperatures (280, 285, 290, 295, and 300 K) and concentrations (36, 45, and 60 mol/l) and compared to that in the bulk solution In order to gain a fundamental insight into the nature of variation in such properties at the interface and the bulk, the formation of hydrogen bonds at various temperatures and concentrations has been investigated It is found that the nature of interaction between various atoms of glycine molecules, as characterized by radial distribution functions, can provide interesting insight into the formation of hydrogen bonds that in turn affect the diffusion coefficients at the interface
30 citations
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TL;DR: In this paper, the amplitudes of normal librations were analyzed using a rigid-body model to parametrize the atomic mean-square displacements of the atoms belonging to the amide ions.
Abstract: Strontium and calcium amide are ionic compounds crystallizing in a tetragonally distorted anatase structure type. They include asymmetrically charged amide ions (NH2-/ND2-) which resemble water molecules in their structure and in their charge distribution. By means of temperature-dependent X-ray scattering measurements an anomalous thermal expansion was observed for both compounds (295 K for Sr(ND2)2, 370 K for Ca(ND2)2). Fourier analyses based on high-resolution neutron powder diffraction experiments carried out in a large temperature range show especially for the deuterium atoms a remarkably large, anisotropic spatial distribution of the probability density function. It is caused by strongly anisotropic librations of the amide ions. The amplitudes of their normal librations were analyzed using a rigid-body model to parametrize the atomic mean-square displacements of the atoms belonging to the amide ions. They can be described as composed of strong rocking librations with weak temperature dependence and ...
30 citations
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TL;DR: In this paper, the excited state intramolecular charge transfer process of a synthesized donor-acceptor naphthalene chromophoric system methyl ester of N, N ′-Dimethylaminonaphthyl-(acrylic)-acid (MDMANA) has been investigated spectroscopically in combination with quantum chemical calculation.
Abstract: The excited state intramolecular charge transfer process of a synthesized donor–acceptor naphthalene chromophoric system methyl ester of N , N ′-Dimethylaminonaphthyl-(acrylic)-acid (MDMANA) has been investigated spectroscopically in combination with quantum chemical calculation. Apart from the local emission the molecule shows a solvent polarity dependent low energy emission from the charge transfer excited state. In polar protic solvents ground state hydrogen bonded clusters of MDMANA are formed which also shows low energy emission. Structural calculation and potential energy surfaces along both the donor and acceptor twist coordinates by considering twisted intramolecular charge transfer (TICT) model at density functional theory (DFT) level predict that a stabilized twisting geometry is responsible for charge transfer emission. The solvent polarity effect on the emission spectra has been explored using time-dependent density functional theory-polarizable continum model (TDDFT-PCM) which correlates well with the experimental spectral data.
30 citations
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TL;DR: In this article, the authors investigated the transformation of hydrogen bonds in the liquid crystal (5CB)-aerosil system under the influence of an electric field with the use of IR spectroscopy methods.
30 citations