Low Temperature Crystal Structure of 5-Hydroxy-1,7-Bis-(4-Hydroxy-3-Methoxy-Phenyl)-Hepta-1,6-Dien-3-one

Abstract  

The title compound 5-Hydroxy-1,7-bis-(4-hydroxy-3-methoxy-phenyl)-hepta-1,6-dien-3-one crystallizes in orthorhombic space group Pca2₁ with two molecules in the asymmetric unit. The unit cell parameters are: a = 35.5368(8), b = 7.7799(2), c = 12.6796(3) ?, D _calc = 1.396 Mgm⁻³, V = 3505.6(2) ?³ and Z = 8. The two aromatic rings in both the molecules are found almost coplanar, their dihedral angles are 18.8° and 13.8°, respectively. The molecular packing is stabilized by strong O–H···O and C–H···O types of hydrogen bonding interactions. The keto and enol groups form an strong O–H···O intra-molecular interaction in both molecules of asymmetric unit. The molecular alignment in the crystal forming a staircase type of stacking through cross link intermolecular interactions.     

Charge density distribution and electrostatic moments of N‐(4‐chloro‐3‐ trifluromethyl‐phenyl)‐2‐ethoxy‐benzamide molecule at the active site of p300 enzyme: A quantum chemical and theoretical charge density study

A Charge density analysis of CTB molecule in gas phase (Form I ) and the same present at the active site (Form II ) of p300 enzyme were performed for the wave functions obtained from the Density functional method (B3LYP) with the basis set 6‐311G**. This study has been carried out to understand the nature of conformational modification, charge redistribution and the change of electrostatic moments of the CTB molecule when present at the active site of p300. The difference of charge density distribution between both forms of CTB molecule explicitly indicates the effect of intermolecular interaction on CTB molecule in the active site. The dipole moment of CTB in the gas phase (9.6 D) has been significantly decreased (4.27 D) when it present at the active site of p300; this large variation is attributed to the charge redistribution in CTB, due to the intermolecular interaction between the CTB and the receptor p300 molecule. The electrostatic potential maps differentiate the difference of electrostatic potential between the two forms. A large electronegative region is found at the vicinity of oxygen and fluorine atoms. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Exploring the conformation,charge density distribution and the electrostatic properties of galanthamine molecule in the active site of AChE using DFT and AIM theory

Quantum chemical calculations and charge density analysis were carried out to understand the geometry, charge density distribution and the electrostatic properties of isolated galanthamine molecule (form I) and for the same lifted out from the active site (form II) of AChE. The optimized geometry of isolated galanthamine was obtained from a hybrid density functional theory (B3LYP/6‐311G**) calculation. A docking analysis on galanthamine with AChE was performed, and the lowest docked energy structure was selected from the active site of AChE for the further study. A single point energy quantum chemical calculation (B3LYP/6‐311G**) was carried out for the lowest energy structure, which was lifted from the galanthamine–AChE complex from molecular docking analysis. The structural comparison between (I) and (II) helps to understand the conformational modification of the galanthamine molecule in the active site. When the molecule present in the active site, the molecular geometry is seen to be significantly altered, specifically, large changes were observed in the outer core of the molecule while the inner core geometry is intact. The bond topological and electrostatic properties of (I) and (II) were calculated. The dipole moment of the galanthamine molecule also increases from 2.09 to 2.67 D in the process. A large negative electrostatic potential region is found at the vicinity of oxygen and nitrogen atoms of the molecule, which predominantly involve strong hydrophobic and electrostatic interactions with the amino acid residues TRP84, PHE330, GLY118, TYR70, and SER122 present in the active site of AChE. © 2013 Wiley Periodicals, Inc.     

Thermal characterization of NaNO3/KNO3 with different concentrations of Al2O3 and TiO2 nanoparticles

Journal of Thermal Analysis and Calorimetry - The thermo-physical properties of NaNO3/KNO3 (solar salt) added with Al2O3 and TiO2 nanoparticles as phase change material in thermal energy storage...