Search results for "MECHANICS"
showing 10 items of 9361 documents
Studies on the interaction of phosphate anions with N-functionalised polyaza[n]paracyclophanes: the role of N-methylation.
2004
The synthesis and interaction of N,N',N'',N'''-tetramethyl-2,6,9,13-tetraaza[14]paracyclophanes (B323Me(4)) with nucleotides and inorganic phosphates is described. An easy methodology is used to define thermodynamic selectivity. The interaction of B323Me4 and ATP has been monitored by (1)H, (31)P NMR and by molecular mechanics, ruling out the possibility of the participation of pi-stacking interactions. Results show that N-methylation is accompanied by a strong increase in the interaction of the resulting macrocycle with ATP.
Advanced descriptors for long-range noncovalent interactions between SARS-CoV-2 spikes and polymer surfaces.
2021
The recent pandemic triggered numerous societal efforts aimed to control and limit the spread of SARS-CoV-2. One of these aspects is related on how the virion interacts with inanimate surfaces, which might be the source of secondary infection. Although recent works address the adsorption of the spike protein on surfaces, there is no information concerning the long-range interactions between spike and surfaces, experimented by the virion when is dispersed in the droplet before its possible adsorption. Some descriptors, namely the interaction potentials per single protein and global potentials, were calculated in this work. These descriptors, evaluated for the closed and open states of the sp…
Phase selective synthesis of ZnS nanoparticles from structurally new dithiocarbamate precursor
2015
Abstract A phase selective solvothermal synthesis of ZnS (wurzite) nanoparticles with a flower-like morphology using a dithiocarbamate precursor, [Zn(4-dpmpzdtc)2(dpmpz)] (1) (where, dpmpz=(diphenylmethyl)piperazine), is described. The nanoparticles were identified as ZnS (wurzite) with the particle size of about 3 to 10 nm by scanning and transmission electron microscopy as well as powder X-ray diffraction (XRD). In addition, the precursor complex 1 was characterized using single crystal X-ray diffraction.
The Nonlocal Correlation Density Functional VV10
2015
Abstract In this chapter, we review the most relevant attempts to merge the Vydrov and van Voorhis nonlocal density-dependent functional kernel (VV10) with modern density functionals to accurately describe van der Waals interactions with a reasonable computational cost. The chapter is organized by providing first an introduction of the relevance of van der Waals interactions and the difficulties of common density functionals to describe these forces. Second, the historical developments that eventually give rise to the most modern formulation of the nonlocal density functional VV10 are briefly addressed. Then, an overview of its technical formulation, adjustable parameters, and implementatio…
Synthesis of Symmetric Ethers Using Monocationic and Dicationic Acidic Ionic Liquids
2018
A series of monocationic and dicationic -SO3H functionalized Brønsted acidic ionic liquids (BAILs) are synthesized using different amines int.al., N,N,N′,N′-tetramethylethylenediamine, 1-methylimidazole, pyridine and alkylating agents 1,3-propane- and 1,4-butanesultones. The Hammett acidity (H0) and thermal properties by TG-DSC techniques are investigated. These ionic liquids have been applied to catalyze the dehydration reaction of aliphatic long chain alcohols (1-heptanol, 1-octanol, 1-decanol) at 195 °C. The optimization of reaction conditions and use of dicationic ionic liquids allow to reach rather high yields of symmetric diheptyl ether and dioctyl ether. The reusability of ionic liqu…
Effect of S1 Torsional Dynamics on the Time-Resolved Fluorescence Spectra of 9,9‘-Bianthryl in Solution
1997
Time-resolved fluorescence spectra of 9,9‘-bianthryl (BA) were measured in methylcyclohexane (MCH) and a Decalin−isooctane (D−ISOO) mixture at several temperatures between 127 and 200 K. A suitable...
Soluble organosilicon micronetworks with spatially confined reaction sites
1997
Influence of Nanoclay Additive on Mechanical Properties of Bio-Based Polyurethane Nanocomposites
2013
This paper is about investigation of the bio-based polyurethanes from the rapeseed oil polyols and their modification with montmorillonite nanoparticles. The results of hardness and tensile properties investigation of polyurethane / montmorillonite nanocomposites are presented.