Dipole moments and molecular complexes

1964 ◽  
Vol 61 ◽  
pp. 125-131 ◽  
Author(s):  
J. W. Smith
Keyword(s):  
Dipole Moments ◽  
Molecular Complexes

Probing massive cold cores discovered by ISO in quiescent galactic molecular complexes

2002 ◽  
Vol 4 ◽  
pp. 133-133
Author(s):  
D. Teyssier ◽  
P. Hennebelle ◽  
M. Pérault
Keyword(s):  
Molecular Complexes

Dipole moments and tautomeric equilibria of some aroylacetanilides

1981 ◽  
Vol 78 ◽  
pp. 155-159 ◽  
Author(s):  
Magdi M. Naoum ◽  
Hakim G. Shinouda ◽  
Ahmed S. Shawali ◽  
Hanna A. Rizk
Keyword(s):  
Dipole Moments ◽  
Tautomeric Equilibria

A Transferable, Polarisable Force Field for Ionic Liquids

2019 ◽  
Author(s):  
Kateryna Goloviznina ◽  
José N. Canongia Lopes ◽  
Margarida Costa Gomes ◽  
Agilio Padua
Keyword(s):  
Ionic Liquids ◽  
Force Field ◽  
Force Fields ◽  
Dipole Moments ◽  
Van Der Waals Interactions ◽  
First Principles Calculations ◽  
Ion Diffusion ◽  
Fixed Integer ◽  
Molecular Compounds ◽  
Induced Dipoles

A general, transferable polarisable force field for molecular simulation of ionic liquids and their mixtures with molecular compounds is developed. This polarisable model is derived from the widely used CL\&P fixed-charge force field that describes most families of ionic liquids, in a form compatible with OPLS-AA, one of the major force fields for organic compounds. Models for ionic liquids with fixed, integer ionic charges lead to pathologically slow dynamics, a problem that is corrected when polarisation effects are included explicitly. In the model proposed here, Drude induced dipoles are used with parameters determined from atomic polarisabilities. The CL\&P force field is modified upon inclusion of the Drude dipoles, to avoid double-counting of polarisation effects. This modification is based on first-principles calculations of the dispersion and induction contributions to the van der Waals interactions, using symmetry-adapted perturbation theory (SAPT) for a set of dimers composed of positive, negative and neutral fragments representative of a wide variety of ionic liquids. The fragment approach provides transferability, allowing the representation of a multitude of cation and anion families, including different functional groups, without need to re-parametrise. Because SAPT calculations are expensive an alternative predictive scheme was devised, requiring only molecular properties with a clear physical meaning, namely dipole moments and atomic polarisabilities. The new polarisable force field, CL\&Pol, describes a broad set set of ionic liquids and their mixtures with molecular compounds, and is validated by comparisons with experimental data on density, ion diffusion coefficients and viscosity. The approaches proposed here can also be applied to the conversion of other fixed-charged force fields into polarisable versions.<br>

Influence of β-Cyclodextrin and Hydroxypropyl-β-Cyclodextrin on Enhancement of Solubility and Dissolution of Isradipine

2017 ◽  
Vol 10 (3) ◽  
pp. 3752-3757
Author(s):  
Narendar D ◽  
Ettireddy S
Keyword(s):  
Inclusion Complex ◽  
Dissolution Rate ◽  
Solid Dispersions ◽  
Physical Stability ◽  
Molecular Complexes ◽  
In Vitro Dissolution ◽  
Molar Ratio ◽  
Phase Solubility ◽  
Cyclodextrin Complexation

The content of this investigation was to study the influence of β-cyclodextrin and hydroxy propyl-β-cyclodextrin complexation on enhancement of solubility and dissolution rate of isradipine. Based on preliminary phase solubility studies, solid complexes prepared by freeze drying method in 1:1 molar ratio were selected and characterized by DSC for confirmation of complex formation. Prepared solid dispersions were evaluated for drug content, solubility and in vitro dissolution. The physical stability of optimized formulation was studied at refrigerated and room temperature for 2 months. Solid state characterization of optimized complex performed by DSC and XRD studies.  Dissolution rate of isradipine was increased compared with pure drug and more with HP-β-CD inclusion complex than β-CD. DSC and XRD analyzes that drug was in amorphous form, when the drug was incorporated as isradipine β-CD and HP-β-CD inclusion complex. Stability studies resulted in low or no variations in the percentage of complexation efficiency suggesting good stability of molecular complexes. The results conclusively demonstrated that the enhancement of solubility and dissolution rate of isradipine by drug-cyclodextrin complexation was achieved.   

Molecular Complexes of Monoammonium Glycyrrhizinate with Alphahederin and Hederasaponin C

2015 ◽  
Vol 12 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Leonid A. Yakovishin ◽  
Vladimir I. Grishkovets ◽  
Elena N. Korzh
Keyword(s):  
Molecular Complexes ◽  
Hederasaponin C
Sign in / Sign up

Export Citation Format

Share Document