scholarly journals Hydrogen-bonded assembly and binding affinity of the multi-point acceptor and isophthalic acid

2006 ◽  
Vol 4 (4) ◽  
pp. 732-742 ◽  
Author(s):  
Lingjia Xu ◽  
Liangliang Zhu ◽  
Shi Wu ◽  
Xiaopeng Chen ◽  
Qiwen Teng
Keyword(s):  
Hydrogen Bonding ◽  
Binding Energy ◽  
Hydrogen Bonds ◽  
Small Molecules ◽  
Electronic Spectra ◽  
Isophthalic Acid ◽  
Steric Effects ◽  
Am1 Method ◽  
Ir Frequencies ◽  
Negative Binding Energy

AbstractSupermolecular complexes formed by oligophenyleneethynylene derivatives and isophthalic acid were studied using AM1 method to obtain binding energy. Electronic spectra and IR spectra of the complexes were calculated by INDO/CIS and AM1 methods based on AM1 geometries. Results indicated that the dimer could be formed by the monomers via hydrogen bonding because of the negative binding energy. Binding energy of the complexes was affected by electronegativity and steric effects of the substituents. The first UV absorptions and IR frequencies of N-H bonds of the complexes were both red-shifted compared with those of the monomers. The complexes could bind small molecules via hydrogen bonds, resulting in the change in UV absorptions and an increase in IR frequencies of N-H bonds.

scholarly journals Theoretical studies on the binding affinities of β-cyclodextrin to small molecules and monosaccharides

2006 ◽  
Vol 4 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Sicong Chen ◽  
Qiwen Teng ◽  
Shi Wu
Keyword(s):  
Binding Energy ◽  
Small Molecules ◽  
Am1 Method ◽  
Hydroxyl Groups ◽  
Binding Affinities ◽  
Binding Ability ◽  
Solvent Molecules ◽  
Equilibrium Geometries ◽  
Negative Binding Energy ◽  
Optimized Geometries

AbstractEquilibrium geometries and electronic structures of complexes between β-cyclodextrin (β-CD) and some small molecules as well as monosaccharides were investigated by Austin Model 1 (AM1) to obtain binding energy of the complexes. It was indicated that β-CD could bind the structurally similar solvent molecules and monosaccharides because of the negative binding energy of the complexes, and especially could show the chiral binding ability to monosaccharides with more hydroxyl groups, due to its chiral characteristics. The complexes were stabilized by the hydrogen bonding between β-CD and guests. Based on the AM1 optimized geometries, the IR spectra were calculated by AM1 method. Vibration frequencies of O-H bonds in the guests were red-shifted owing to the weakening of the O-H bonds with the formation of the complexes.

Study of Hydrogen Bonding in Carboxylic Acids by the MNDO/M Method

1994 ◽  
Vol 59 (6) ◽  
pp. 1251-1260 ◽  
Author(s):  
Michal Bureš ◽  
Jaroslav Bezus
Keyword(s):  
Experimental Data ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Carboxylic Acids ◽  
Promising Method ◽  
Semiempirical Methods ◽  
Am1 Method ◽  
Bond Lengths ◽  
Pm3 Method

The semiempirical methods MNDO/M, AM1 and PM3 were applied to the study of hydrogen bonds in carboxylic acids. The calculated hydrogen bond lengths and enthalpies of dimerization were compared with experimental data. The AM1 method fails to properly describe systems with strong hydrogen bonds. The PM3 method predicts the hydrogen bond lengths correctly but underestimates systematically the enthalpies of dimerization. MNDO/M appears to be a promising method for the treatment of association of carboxylic acids.

Statistical analysis of noncovalent interactions of anion groups in crystal structures. I. Hydrogen bonding of sulfate anions

1996 ◽  
Vol 52 (4) ◽  
pp. 677-684 ◽  
Author(s):  
L. Chertanova ◽  
C. Pascard
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Small Molecules ◽  
Crystal Structures ◽  
Noncovalent Interactions ◽  
Data Set ◽  
Hydrogen Bond Acceptor ◽  
Covalently Bonded ◽  
Different Types

The hydrogen-bond acceptor characteristics of sulfate dianions are analyzed in crystal structures of small molecules. For 85 anions, neither coordinated to metal ions nor covalently bonded, 697 hydrogen bonds are faund. Of these, 266 (38%) are the O...H—O type and 431 (62%) are the O...H—N type, proportions that correspond well to the stoichiometry of the compounds studied and indicate no preference for a particular donor. The analysis of the data set, after classifying the hydrogen bonds according to the different types of donors, shows that O...H—O bonds are more linear than O...H—N. The anion oxygen–acceptor function is characterized by multiple hydrogen bonding. Only in 56 cases does a sulfate oxygen participate in a single hydrogen bond. In most cases every sulfate oxygen is coordinated by two (187 cases) or three (89 cases) hydrogen bonds. For three H donors, the preferred coordination geometry of the sulfate oxygen is pyramidal. The most frequent coordination around a sulfate dianion is with eight to ten H donors. Thus, sulfate dianions can play a significant cohesive role in molecular aggregation.

TIME-DEPENDENT DENSITY FUNCTIONAL THEORY STUDY ON DYNAMICS OF HYDROGEN BONDING IN EXCITED STATES OF TRANS-ACETANILIDE IN METHANOL SOLVENT

2012 ◽  
Vol 11 (02) ◽  
pp. 421-435 ◽  
Author(s):  
XIAOYU ZHANG ◽  
WEIPING ZHANG ◽  
FANKAI MENG
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Excited States ◽  
Electronic Spectra ◽  
Density Functional ◽  
Excitation Energies ◽  
Intermolecular Hydrogen Bonds ◽  
Functional Theory ◽  
Tddft Method

The hydrogen-bonding dynamics in both singlet and triplet excited states of the trans-acetanilide ( AA ) in methanol ( MeOH ) solvent was investigated using the time-dependent density functional theory (TDDFT) method. Geometric optimizations of the hydrogen-bonded AA–MeOH complexes considered here as well as the isolated AA and MeOH molecules were performed using density functional theory (DFT) method. At the same time, the TDDFT method was performed to calculate the electronic transition energies and corresponding oscillation strengths of all the compounds in the low-lying electronically excited states. In this study, only the intermolecular hydrogen bonds C=O⋯H–O and N–H⋯O–H can be formed. A theoretical forecast that changes of hydrogen bonds in the low-lying electronic excited states was proposed. We discussed not only ground-state geometric structures and electronic excitation energies but also frontier molecular orbitals and electron density transition. The intermolecular hydrogen bonds between AA and MeOH molecules play an important role in the geometric structures and electronic excitation energies. Zhao et al. have put forward the relationship between the electronic spectra and hydrogen bonding dynamics for the first time. According to Zhao's rule, a redshift of the relevant electronic spectra will appear if hydrogen bond is strengthened, while the hydrogen bond weakening can make an electronic spectra shift to blue.

scholarly journals Hydrogen Bonds: Raman Spectroscopic Study

2021 ◽  
Vol 22 (10) ◽  
pp. 5380
Author(s):  
Boris A. Kolesov
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Raman Spectra ◽  
Temperature Region ◽  
Vibrational Frequency ◽  
Chemical Compounds ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Proton Dynamics

The work outlines general ideas on how the frequency and the intensity of proton vibrations of X–H×××Y hydrogen bonding are formed as the bond evolves from weak to maximally strong bonding. For this purpose, the Raman spectra of different chemical compounds with moderate, strong, and extremely strong hydrogen bonds were obtained in the temperature region of 5 K–300 K. The dependence of the proton vibrational frequency is schematically presented as a function of the rigidity of O-H×××O bonding. The problems of proton dynamics on tautomeric O–H···O bonds are considered. A brief description of the N–H···O and C–H···Y hydrogen bonds is given.

scholarly journals Crystal structure of 5-[(4-carboxybenzyl)oxy]isophthalic acid

2016 ◽  
Vol 72 (8) ◽  
pp. 1219-1222
Author(s):  
Md. Serajul Haque Faizi ◽  
Musheer Ahmad ◽  
Akram Ali ◽  
Vadim A. Potaskalov
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Three Dimensional ◽  
Molecular Shape ◽  
Isophthalic Acid ◽  
Compound C ◽  
Dimensional Network ◽  
Benzene Rings

The molecular shape of the title compound, C16H12O7, is bent around the central CH2—O bond. The two benzene rings are almost perpendicular to one another, making a dihedral angle of 87.78 (7)°. In the crystal, each molecule is linked to three others by three pairs of O—H...O hydrogen bonds, forming undulating sheets parallel to thebcplane and enclosingR22(8) ring motifs. The sheets are linked by C—H...O hydrogen bonds and C—H...π interactions, forming a three-dimensional network.

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