基于24-冠-8大环化合物构筑的人工分子器件和分子机器

简要阐述了分子器件和分子机器的相关概念,按照调控方式分类综述了基于24冠8的准轮烷、轮烷和索烃大环化合物构筑的分子器件和分子机器等在超分子领域的研究进展并对研究前景作了展望.     

Measurements of binary diffusion coefficients and retention factors for dibenzo-24-crown-8 and 15-crown-5 in supercritical carbon dioxide by chromatographic impulse response technique

Binary diffusion coefficients D₁₂ and retention factors k for dibenzo-24-crown-8 and 15-crown-5 ethers at 308.18 and 313.20 K, and vitamin K₁ at 313.20 K were measured in supercritical carbon dioxide by the chromatographic impulse response technique, and the effects of molecular shapes on the D₁₂ values were studied. At 313.2 K and 11.0 MPa the D₁₂ value of 15-crown-5 was higher than that predicted from the D₁₂ correlation with molecular weight MW over the range from 32 of methanol to 1138 of trinervonin reported in our previous studies, while the D₁₂ value of dibenzo-24-crown-8, disk shape molecule with MW = 448.5, was almost in agreement with that of vitamin K₁, long chain molecule with MW = 450.7, and with those predicted from the correlation.     

Estimation of the Elastic Modulus of Cellulose Crystal by Molecular Mechanics Simulation

The elastic modulus of natural cellulose crystal was estimated by the molecular simulation technique. Values between 124 and 155 GPa were derived for the reasonable cellulose I_β crystal model that were nearly equal to the observed value of 138 GPa. While the second-generation force fields were found to be superior to the first-generation ones for the optimization of cellulose structure, neither of these was good enough to achieve the structural optimization. They were, however, adequate for estimating the mechanical properties of cellulose, especially the second-generation force fields. The lateral (that is, intermolecular) interactions between cellulose chains were found to play an important role in the expression of the mechanical properties of cellulose crystal.     

An In Silico investigation for acyclovir and its derivatives to fight the COVID-19: Molecular docking,DFT calculations,ADME and td-Molecular dynamics simulations

In the present work, we have designed three molecules, acyclovir (A), ganciclovir (G) and derivative of hydroxymethyl derivative of ganciclovir (CH₂OH of G, that is D) and investigated their biological potential against the Mpro of nCoV via in silico studies. Further, density functional theory (DFT) calculations of A, G and D were performed using Gaussian 16 on applying B3LYP under default condition to collect the information for the delocalization of electron density in their optimized geometry. Authors have also calculated various energies including free energy of A, G and D in Hartree per particle. It can be seen that D has the least free energy. As mentioned, the molecular docking of the A, G and D against the Mpro of nCoV was performed using iGemdock, an acceptable computational tool and the interaction has been studied in the form of physical data, that is, binding energy for A, G and D were calculated in kcal/mol. It can be seen the D showed effective binding, that is, maximum inhibition that A and G. For a better understanding for the inhibition of the Mpro of nCoV by A, G and D, temperature dependent molecular dynamics simulations were performed. Different trajectories like RMSD, RMSF, Rg and hydrogen bond were extracted and analyzed. The results of molecular docking of A, G and D corroborate with the td-MD simulations and hypothesized that D could be a promising candidate to inhibit the activity of Mpro of nCoV.     

Molecular Mechanics Calculations on Chelates of Titanium(IV), Vanadium(IV/V), Copper(II), Nickel(II), Molybdenum(IV/V), Rhenium(IV/V) and Tin(IV) with Di- and Tridentate Ligands Using the New Extensible Systematic Force Field (ESFF)—An Empirical Study

Force field calculations were performed on a series of 27 transition metal complexes of titanium(IV), vanadium(IV/V), copper(II), nickel(II), molybdenum(IV/V), rhenium(IV/V), and tin(IV) with a broad variety of di- or tridentate ligands in order to find a reliable scheme for determining the molecular structure of such chelates with the new Extensible Systematic Force Field (ESFF). A good agreement between theoretical results and experimental data was achieved. In some cases an unspecific fitting of the force field was necessary.