scholarly journals Stoichiometric analysis of competing intermolecular hydrogen bonds using infrared spectroscopy

RSC Advances ◽  
2018 ◽  
Vol 8 (42) ◽  
pp. 23481-23488 ◽  
Author(s):  
Ian Seungwan Ryu ◽  
Xiaohui Liu ◽  
Ying Jin ◽  
Jirun Sun ◽  
Young Jong Lee
Keyword(s):  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Infrared Spectra ◽  
Quantitative Information ◽  
Intermolecular Hydrogen Bonds ◽  
Stoichiometric Analysis

Stoichiometric analysis of infrared spectra from UDMA and TEG-DVBE mixtures provides quantitative information on competing hydrogen bonds and intermolecular interactions in equilibrium.

Crystal structures and Hirshfeld surface analysis of four 1,4-bis(methoxyphenyl)-2,3-diazabuta-1,3-dienes: comparisons of the intermolecular interactions in related compounds

2019 ◽  
Vol 234 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Ligia R. Gomes ◽  
John N. Low ◽  
Nathasha R. de L. Correira ◽  
Thais C.M. Noguiera ◽  
Alessandra C. Pinheiro ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Three Dimensional ◽  
Hirshfeld Surface ◽  
Dimensional Structure ◽  
Intermolecular Hydrogen Bonds ◽  
Π Interactions ◽  
Isomeric Compound ◽  
Related Compounds

Abstract The crystal structures of four azines, namely 1-3-bis(4-methoxyphenyl)-2,3-diaza-1,4-butadiene, 1, 1,3-bis(2,3-dimethoxyphenyl)-2,3-diaza-1,4-butadiene, 2, 1,3-bis(2-hydroxy-3-methoxyphenyl)-2,3-diaza-1,4-butadiene, 3, and 1,3-bis(2-hydroxy-4-methoxyphenyl)-2,3-diaza-1,4-butadiene, 4, are reported. Molecules of 3 and 4, and both independent molecules of 2, Mol A and Mol B, possess inversion centers. The central C=N–N=C units in each molecule is planar with an (E,E) conformation. The intermolecular interactions found in the four compounds are C–H···O, C–H–N, C–H---π and π---π interactions. However, there is no consistent set of intermolecular interactions for the four compounds. Compound, 1, has a two-dimensional undulating sheet structure, generated from C–H···O and C–H···N intermolecular hydrogen bonds. The only recognized intermolecular interaction in 2 is a C–H···O hydrogen bond, which results in a zig-zag chain of alternating molecules, Mol A and Mol B. While 3 forms a puckered sheet of molecules, solely via C–H···π interactions, its isomeric compound, 4, has a more elaborate three-dimensional structure generated from a combination of C–H···O hydrogen bonds, C–H···π and π···π interactions. The findings in this study, based on both PLATON and Hirshfeld approaches, for the four representative compounds match well the reported structural findings in the literature of related compounds, which are based solely on geometric parameters.

Effects of Complexation on the Glass Transition Temperature of Polymers

1990 ◽  
Vol 215 ◽  
Author(s):  
Michael F. Roberts ◽  
Samson A. Jenekhe
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Lewis Acid ◽  
Dominant Effect ◽  
Intermolecular Hydrogen Bonds ◽  
Aromatic Polyamides ◽  
Rigid Chain

AbstractThe effects of Lewis acid complexation on the glass transition temperature (Tg) of several polymers with strong intermolecular interactions was investigated. The decrease in the Tg due to GaCl3 complexation of aliphatic and aromatic polyamides was 40–600° C and 148° C, respectively, and was shown to originate from scission of the intermolecular hydrogen bonds. The reduction in the Tg due to GaCl3 complexation of rigid–chain polymers was greater that 325° C and can be explained by the mitigation of the otherwise strong van der Waals forces in the pristine polymers. Thus, the dominant effect of intermolecular interactions on the Tg of several polymers has been probed by Lewis acid complexation.

scholarly journals Preparation and Properties of Bacterial Cellulose/Alginate Blend Bio-Fibers

2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Shuai Zhang ◽  
Jin Luo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Bacterial Cellulose ◽  
Tensile Tests ◽  
Intermolecular Hydrogen Bonds ◽  
Scanning Electron

LiOH/urea/thiourea aqueous systems have been successfully applied to the dissolution of bacterial cellulose (BC) and alginate (AL) to prepare blend fibers. Morphology, compatibility and mechanical properties of the blend fibers were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and tensile tests. The analyses indicated a good miscibility between alginate and bacterial cellulose, because of the strong interaction from the intermolecular hydrogen bonds. The mechanical properties of BC/AL blend fibers were significantly improved by introducing bacterial cellulose.

scholarly journals The synthesis, crystal structure and Hirshfeld analysis of 4-(3,4-dimethylanilino)-N-(3,4-dimethylphenyl)quinoline-3-carboxamide

2020 ◽  
Vol 76 (2) ◽  
pp. 201-207
Author(s):  
Ligia R. Gomes ◽  
John Nicolson Low ◽  
Fernanda Borges ◽  
Alexandra Gaspar ◽  
Francesco Mesiti
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Surface Analysis ◽  
Intermolecular Interactions ◽  
Pyridine Ring ◽  
Hirshfeld Surface ◽  
Intermolecular Hydrogen Bonds ◽  
Pyramidal Geometry ◽  
Hirshfeld Analysis ◽  
Lattice Energies

The structure of the title quinoline carboxamide derivative, C26H25N3O, is described. The quinoline moiety is not planar as a result of a slight puckering of the pyridine ring. The secondary amine has a slightly pyramidal geometry, certainly not planar. Both intra- and intermolecular hydrogen bonds are present. Hirshfeld surface analysis and lattice energies were used to investigate the intermolecular interactions.

scholarly journals Intermolecular Interactions Required for the Formation of Liquid Microcrystals Produced by the Precursors Self-Organized from Protonated TPP Dimers

Proceedings ◽  
2018 ◽  
Vol 2 (14) ◽  
pp. 1112 ◽  
Author(s):  
Alexander Udal’tsov
Keyword(s):  
Carbon Dioxide ◽  
Infrared Spectroscopy ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Crystallization Process ◽  
Thin Layers ◽  
Molecular Characteristics ◽  
Self Organized ◽  
Local Areas ◽  
Vibrational Bands

Features of solute-solvent intermolecular interaction establishing hydrogen bonds were studied in view of proton sharing in the O---H+–O moiety that is the prerequisite for proton moving through water. Liquid microcrystals are expected to be formed due to the protons moving through water confined in their precursors. Among the different oxygen-containing organic solvents well-dissolved in water, tetrahydrofuran (THF) has been found the most suitable since it forms a molecular complex with carbon dioxide dissolved in water producing the ions H+ and (HCO3)−. This three-component complex exhibits in infrared spectra vibrational bands characterizing the complex and the proton sharing in the O---H+–O moiety. Assemblies consisting of mono- protonated meso-tetraphenylporphine (TPP) dimers self-organized into submicroscopic particles in solution and water with 0.86 mol·L−1 THF have been investigated by infrared spectroscopy, SEM, and AFM in thin layers. Earlier found tight water covering the submicroscopic particles is proved to exhibit an ordered and non-ordered local areas on the surface. Molecular characteristics estimated for the three-component complex involving THF suggest that the complex together with the TPP dimers partakes in the crystallization process providing protons moving through water.

Advances in the Understanding of the Cannabinoid Receptor 1 – Focusing on the Inverse Agonists Interactions

2019 ◽  
Vol 26 (10) ◽  
pp. 1908-1919 ◽  
Author(s):  
Silvana Russo ◽  
Walter Filgueira De Azevedo
Keyword(s):  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Cannabinoid Receptor ◽  
Structural Information ◽  
New Drugs ◽  
Crystallographic Structure ◽  
Complex Structures ◽  
Cannabinoid Receptor 1 ◽  
Intermolecular Hydrogen Bonds ◽  
Inverse Agonists

Background: Cannabinoid Receptor 1 (CB1) is a membrane protein prevalent in the central nervous system, whose crystallographic structure has recently been solved. Studies will be needed to investigate CB1 complexes with its ligands and its role in the development of new drugs. Objective: Our goal here is to review the studies on CB1, starting with general aspects and focusing on the recent structural studies, with emphasis on the inverse agonists bound structures. Methods: We start with a literature review, and then we describe recent studies on CB 1 crystallographic structure and docking simulations. We use this structural information to depict protein-ligand interactions. We also describe the molecular docking method to obtain complex structures of CB 1 with inverse agonists. Results: Analysis of the crystallographic structure and docking results revealed the residues responsible for the specificity of the inverse agonists for CB 1. Most of the intermolecular interactions involve hydrophobic residues, with the participation of the residues Phe 170 and Leu 359 in all complex structures investigated in the present study. For the complexes with otenabant and taranabant, we observed intermolecular hydrogen bonds involving residues His 178 (otenabant) and Thr 197 and Ser 383 (taranabant). Conclusion: Analysis of the structures involving inverse agonists and CB 1 revealed the pivotal role played by residues Phe 170 and Leu 359 in their interactions and the strong intermolecular hydrogen bonds highlighting the importance of the exploration of intermolecular interactions in the development of novel inverse agonists.

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