No abstract

PILs are promising solvent systems for CO2 absorption and transformations. Although previously tremendous work has been paid to synthesize functionalized PILs to achieve a high-performance absorption, the underlying mechanisms are far less investigated and still not clear. In this work, a series of DBU-based PILs, i.e., [DBUH][X], with anions of various basicities were synthesized. The basicities of the anions were accurately measured in [DBUH][OTf] or extrapolated from the known linear correlations. The apparent kinetics as well as the capacities for CO2 absorption in these PILs were studied systematically. The results show that the absorption rate and capacity in [DBUH][X] are in proportional to the basicity of PIL, i.e., a more basic PIL leads to a faster absorption rate and a higher absorption capacity. In addition, the spectroscopic evidences and correlation analysis indicate that the capacity and mechanism of CO2 absorption in [DBUH][X] are essentially dictated by the basicities of anions of these PILs.

Accurate acidity studies of different families of substrates in a pure protic ionic liquid (PIL) show that solute ions in the PIL are free from specific ion associations and the solvation behaviour of PILs is closely related to the number of dissociable protons.

In the NeurIPS 2018 Artificial Intelligence for Prosthetics challenge, participants were tasked with building a controller for a musculoskeletal model with a goal of matching a given time-varying velocity vector. Top participants were invited to describe their algorithms. In this work, we describe the challenge and present thirteen solutions that used deep reinforcement learning approaches. Many solutions use similar relaxations and heuristics, such as reward shaping, frame skipping, discretization of the action space, symmetry, and policy blending. However, each team implemented different modifications of the known algorithms by, for example, dividing the task into subtasks, learning low-level control, or by incorporating expert knowledge and using imitation learning.

Av ery broad acidity scale ( % 40 pK units) for about 400 N-heterocyclic carbenep recursors (NHCPs) with various backbones and electronic features, including imidazolylidenes, 1,2,4-triazolylidenes, cyclic diaminocarbenes (CDACs), diamidocarbenes (DACs), thiazolylidenes, cyclic (alkyl)(amino)carbenes (CAACs) and mesoionic carbenes (MICs), was established in DMSO by aw ell examined computational method. Varying the backbone structure or flanking N-substituents can have different extent of acidifying effects, de-pending on both the nature and number of substituent(s). The Gibbs energies (DG r s) for the reactions between the corresponding NHCs and CO 2 were also calculated.T here is a good linear correlation between the pK a so fm ostN HCPs and DG r s, suggestingt hat ag reater basicity of NHC leads to am ore stable NHC-CO 2 adduct. Interestingly,t he nearby asymmetrice nvironment has virtually no differential effect on the acidities of the chiral NHCP enantiomers, but has a pronounced effect on the DG r values.[a] Dr.

The densities and viscosities of binary mixtures of 1-ethyl-3-methylimidazolium heptachlorodialuminate and tetrachloroaluminate ionic liquids with different molar compositions were measured by high-precision vibrating tube densimeter and automated microviscometer from 293.15 to 353.15 K. On this basis, the excess molar volumes and excess viscosities of binary mixtures were also calculated for the first time. All the experimental data were well fitted by the empirical equations. According to the results of computational calculations, enhanced molecular symmetry and molar concentration of heptachlorodialuminate anion usually lead to higher density. The hydrogen bonding among ions is confirmed as one of the most important structural parameters in determining the viscosity of ionic liquids. It shows that Lewis acidic 1-ethyl-3-methylimidazolium chloroaluminate can be treated as the classic binary mixtures of heptachlorodialuminate and tetrachloroaluminate ionic liquids. Looser packing and/or weaker interionic interaction probably occurs after the formation of binary mixtures. The results and conclusions of this work will help to promote future research and application of chloroaluminate ionic liquids.

A Bronsted basicity scale (∼24 pK units) for 85 commonly seen imidazole-, imidazoline-, triazole-, and thiazole-based N-heterocyclic olefins (NHOs) in DMSO was established using a well-examined computational model. The influence of substituents on the Bronsted basicities of these NHOs was investigated through basicity comparisons and rationalized by geometric analyses. The Gibbs energy (ΔG r ) of the reaction between NHO and CO 2 was also calculated, which linearly correlates with the basicity of the corresponding NHO, suggesting that the stability of NHO−CO 2 adducts can be evaluated by the basicity of NHOs and a stronger basicity leads to a more stable NHO−CO 2 adduct.

In this work, the antioxidant abilities of NADH coenzyme analogue BNAH, F420 reduction prototype analogue F420H, vitamin C analogue iAscH−, caffeic acid, and (+)-catechin in acetonitrile in chemical reactions were studied and discussed.