Synthesis, hydrogen bond interactions and crystal structure elucidation of some stable 2H-imidazolium salts

Reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) with phthalimide, quinazolinedione, thiophenole and 4-pyridinethiole led to the formation of the hydrogen-bonded salts, imidazolium phthalimide (2), imidazolium quinazolinedione (3), imidazolium thiophenolate (4) and imidazolium 4-pyridinethiolate (5), respectively, in good yield. In crystals of 2, the anion is linked to the imidazolium cation by a C–H···O hydrogen bond, while in 3 and 5 C–H···N hydrogen bonds are observed. In 4, the imidazolium ion is linked to the anion by C–H···S hydrogen bonds. In compounds 2, 3 and 5, the interionic hydrogen bonds are close to linearity, while the interionic hydrogen bond angle in 4 is 148.5(9)°.

Properties of Gel Polymer Electrolyte Based Poly(Vinylidine Fluoride-сo-Hexafluoropropylene) (PVdF-HFP), Lithium Perchlorate (LiClO4) and 1-Butyl-3-Methylimmidazoliumhexafluorophosphate [PF6]

This study reported the preparation and characterization of gel polymer electrolyte (GPE) using poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP), lithium perchlorate (LiClO4) and 1-butyl-3-metilimmidazoliumhexafluorophosphate [PF6]. The GPE were prepared by solution casting technique. [Bmim] [PF6] ionic liquid is used as an additive for the purpose of increasing the ionic conductivity of GPE. Morphological analysis showed that the electrolyte gel polymer sample had a smooth and flat surface with the addition of [Bmim] [PF6] and no phase separation effect was observed. This shows the compatibility between PVdF-HFP and [Bmim] [PF6]. ATR-FTIR analysis showed that C-F bond related peaks experienced peak changes in terms of intensity and peak shifting. This proves the interaction of the imidazolium ion with the fluorine atom through the formation of coordinate bonds. Ionic conductivity analysis showed that PVdF-HFP-[Bmim][PF6] samples reached a maximum room temperature ionic conductivity value of 2.44 × 10-4 S cm-1 at 60 wt.% [Bmim] [PF6]. When 20 wt.% of LiClO4 added to the system, the ionic conductivity increased one magnitude order to 2.20 × 10-3 S cm-1.

The Possible Molecular Mechanism of SARS-CoV-2 Main Protease: New Structural Insights from Computational Methods

Main protease (Mpro) is one of the key enzymes in the life cycle of SARS-CoV-2 that plays a pivotal role in mediating viral replication, transcription, and makes it an attractive drug target for this virus. The catalytic site of this enzyme comprises of a dyad His41 and Cys145 and lacks the third catalytic residue, which is replaced by a stable water molecule (W). The computational structural analysis on crystal data for Mpro protein suggests that W1, W2, His163, and Tyr161 may also play a vital role in the activity of this enzyme and they may act as catalytic partners along with Cys(145)-His(41) catalytic dyad. The thiolate–imidazolium ion-pair between Cys145 (-SH---NE2-) His41 and Cys145 (-SH---NE2-) His163 have been stabilized by W1 (with W2) and Tyr161, respectively. Therefore, unique interactions of W2---W1---ND1-His41-NE2---SH-Cys145 or Cys145-SH---NE2-His163-ND1---OH-Tyr161 in Mpro serve as an excellent drug target for this enzyme and suggest a rethink of the conventional definition of chemical geometry of inhibitor binding site, its shape, and complementarities. Our computational hypothesis suggests two essential clues that may be implemented to design a new inhibitor for Mpro protein. The strategies are: (i) ligand should be occupied either W1 or W2 or both of these position to displace these water molecules from the catalytic region, and (ii) ligand should be made H-bonds with Cys145 (-SH), His41 (NE2/ND1) and His163(NE2) to inhibit Mpro. The results from this computational study could be of interest to the experimental community and also provide a testable hypothesis for experimental validation. Doi: 10.28991/SciMedJ-2020-02-SI-11 Full Text: PDF

Rotational dynamics of the imidazolium ion in cyanide-bridged dielectric framework materials

Quasielastic neutron scattering reveals the geometry and timescale of the dielectric switching dynamics in a series of elpasolite-like framework materials.

Recyclable imidazolium ion-tagged nickel catalyst for microwave-assisted C–S cross-coupling in water using sulfonyl hydrazide as the sulfur source

Recyclable nickel(ii) catalyst promoted sulfenylation of aryl halides with sulfonyl hydrazides in water using microwave irradiation under mild conditions is reported.

Electrochemical reduction of CO2 to ethylene glycol on imidazolium ion-terminated self-assembly monolayer-modified Au electrodes in an aqueous solution

The IL-based SAMs-modified Au electrodes have high selectivity of products from CO2 to ethylene glycol (a maximum of 87%).