Boron-containing fullerene-based salts with cyclic carbonate solvents as electrolytes for Li-ion batteries and beyond.

Replacement of carbon atoms by a heteroatom in fullerene is a promising route that enhances the electronic properties of fullerenes and results in hetero fullerene-based effective agents ensuring applications in vivid fields of the solar cell, cathode materials for batteries, etc. Towards the development of new electrolyte salts, attention has been paid to facilitating ion mobility in particular and moderate stability of the anions in addition. From the atomistic molecular dynamics simulation studies, for the first time, we uncover that the boron-containing hetero fullerene, C59B- anion-based LiC59B, and NaC59B salts in cyclic carbonate solvents can act as efficient electrolytes by improving the transport phenomenon of the metal ions in solution, importantly for Li+ and satisfactorily for Na+ as compared to their commonly used BF4- anion based salts. Additionally, our study revealed that apart from LiC59B, and NaC59B salts, C58B22- based MgC58B2 salt can facilitate the ionic conductivity of the electrolyte. The properties of the proposed electrolyte under an electric field and different temperatures were investigated. Some of the bulk properties of the used electrolytes to some extent were found to be improved in the presence of these salts. The first principle-based electrochemical calculations further justify the stability of the proposed anions. The initial investigation from the Reactive force-field (ReaxFF) based atomistic simulations study elucidates that LiC59B reduces the decomposition of the EC solvent compared to LiBF4 and facilitates solvent stability.

Conformational Features and Hydration Dynamics of Proteins in Cosolvents: A Perspective from Computational Approaches.

The importance of solvent in stabilizing protein structures has long been recognized. Water is the common solvent for proteins, and hydration is elemental in governing protein stability, flexibility, and function through various interactions. The addition of small organic molecules known as cosolvents may deploy stabilization (folding) or destabilization (unfolding) effects on native protein conformations. Despite exhaustive literature, the molecular mechanism by which cosolvents regulate protein conformations and dynamics is controversial. Specifically, the cosolvent behavior has been unpredictable with the nature and concentrations that lead to protein stabilizing/destabilizing effects as it changes in water content near the vicinity of proteins. With the massive development of computational resources, advancement of computational methods, and the availability of numerous experimental techniques, various theoretical and computational studies of proteins in a mixture of solvents have been instigated. The growing interest in such studies has been to unravel the underlying mechanism of protein folding and cosolvent/solvent-protein interactions that have significant implications in biomedical and biotechnological applications. In this mini-review, apart from the brief overview of important theories and force-field model-based cosolvent effects on proteins, we present the current state of knowledge and recent advances in the field to describe cosolvent-guided conformational features of proteins and hydration dynamics from computational approaches. The mini-review further explains the mechanistic details of protein stability in various popularly used cosolvents, including limitations of present studies and future outlooks. The counteracting effects of cosolvent on the proteins in the mixture of stabilizing and destabilizing cosolvents are also presented and discussed.

Molecular recognition of two bioactive coumarin derivatives 7-hydroxycoumarin and 4-methyl-7-hydroxycoumarin by hen egg white lysozyme: Exploring the binding mechanism, thermodynamic parameters and structural changes using multispectroscopic and computational approaches.

Multispectroscopic and computational methods of exploring the interaction between a carrier protein and therapeutic compounds provide a preliminary investigation into establishing the efficacy of such compounds. Here, two coumarin derivatives, 7-hydroxycoumarin (7-HC) and 4-methyl-7-hydroxycoumarin (4-Me-7-HC), were selected to carry out numerous biophysical interaction studies with a model carrier protein, hen egg white lysozyme (HEWL). Fluorescence spectroscopy studies conducted between HEWL and 7-HC/4-Me-7-HC revealed the binding constants (Kb) were in the range of 104 M-1, indicating a moderate nature of binding. The quenching mechanism observed during complexation process was an unusual static quenching due to the effect of temperature on the rate constant. Thermodynamic parameters revealed a positive ΔH and ΔS for HEWL-7-HC/4-Me-7-HC, indicating hydrophobic forces played a dominant role in the interaction process. FRET studies suggested a possible non-radiative energy transfer from the donor (HEWL) to the acceptor (coumarins). Molecular docking studies revealed the interaction of 7-HC/4-Me-7-HC with intrinsic fluorophores, Trp63 and Trp108, Trp108 being an essential residue for binding as proven by molecular dynamic (MD) simulation. MD simulation studies also indicated conformational stability gained by HEWL upon interaction with 7-HC and 4-Me-7-HC. The microenvironment surrounding the Trp residues showed a significant Stoke's shift on carrying out 3-D fluorescence. CD studies revealed a decrease in the alpha helical content of HEWL upon interacting with the ligands. Enzymatic assay conducted for HEWL in the presence of 7-HC/4-Me-7-HC saw an increase in the activity of HEWL, suggesting a change in structural conformation and stability of the protein, altering its activity.Communicated by Ramaswamy H. Sarma.