China
Africa
Explore chapters and articles related to this topic
Molecular Modeling of Imidic Polymers with Advanced Physico-Chemical Properties
Published in Andreea Irina Barzic, Neha Kanwar Rawat, A. K. Haghi, Imidic Polymers and Green Polymer Chemistry, 2021
Sava et al.35 prepared some azopolyimides that were photo-patterned. The chemical structures of the imidic polymers were modeled with Hyper-chem program at the lowest energy. Molecular mechanics approach allowed estimation of certain molecular parameters, like dihedral angles, atomic distances, and bond angles; based on them, the macromolecule geometry is computed and optimized. The azompolyimides have a spatial conformation that is far from being linear rigid rod as widely noticed for aromatic polyimides that lack kinks or pendants in their structure. The adopted shapes of chains impede a close packing and the solvent diffusion among the chains is facilitated resulting in a higher solubility. The chain geometry is less affected by the nature of substituent (para-, ortho-methyl, or chlorine) bonded to the azobenzene segments. The polymers containing -COCH3 or -COCl tend to have an extended macromolecular chain. In other words, the type of kinks and pendant groups affect the spatial conformation of the polyimide and implicitly its response to UV patterning.
Molecular simulations of water and ion transport through nanoporous membranes
Published in Alberto Figoli, Jan Hoinkis, Sacide Alsoy Altinkaya, Jochen Bundschuh, Application of Nanotechnology in Membranes for Water Treatment, 2017
Richard Renou, Minxia Ding, Haochen Zhu, Aziz Ghoufi, Anthony Szymczyk
The dihedral angle potential describes the interaction arising from torsional forces in molecules. It requires the specification of four atomic positions: Utorsion=∑dihedral∑nA[1+cos(ϖϕ−δ)]
Theoretical Calculations on AZA-Scorpiand Systems
Published in A. K. Haghi, Ana Cristina Faria Ribeiro, Lionello Pogliani, Devrim Balköse, Francisco Torrens, Omari V. Mukbaniani, Applied Chemistry and Chemical Engineering, 2017
J. V. De Julian-Ortiz, L. Pogliani, E. Besalú, B. Verdejo, E. García-España
Setting the conformation A as the initial one, the molecule structure was passed from monoprotonated to triprotonated. The conformational search was performed by the Monte Carlo multiple minimum (MCMM) method11–13 with the MM+ force field.14 The free rotation of the dihedral angles comprising the pendant arm that joins the two rings (tail) was allowed. This method finds the lowest energy conformations of a molecule by randomly varying specified dihedral angles to generate new starting conformations. These were then minimized.
Synthesis and characterisation of formohydrazide derivatives as potential antimicrobial agents: molecular docking and DFT studies
Published in Molecular Physics, 2022
S. Gunavathi, R. Venkateswaramoorthi, K. Arulvani, S. Bharanidharan
The title molecule belongs to C1 point group harmony. The optimised molecular structure of 3d is shown in Figure 6, with the numbering scheme adopted in this study. The calculated geometrical parameters of 3d were calculated by B3LYP with 6-311++G(d,p) basis set are listed in Table 4. The C–C bond lengths of six-membered rings are relatively equal to 1.39Å/B3LYP with some exceptions. Because in benzene, all the C–C bond lengths are equal (equal distribution of π-electrons around the benzene ring). In this study, the benzene ring bond angle values were nearly around 120°. The dihedral angle values reveal the planar of the present molecule.