Nanoscale Configuration of Clay-Interlayer Chemistry: A Precursor to Enhancing Flame Retardant Properties

Nanomaterials are proving to be pivotal to the evolution of controllable, cost-effective and environmentally safe technologies. An important concern is the impact of low-dimensional compositional materials and their ability to significantly reduce the hazardous nature of flame retardants that are reputably harmful through unchecked inhalation. While eco-friendly and recyclable alternatives are necessary requirements to function as replacements for the ‘Next Generation’ of flame retardants, the underlying ‘Chemistry’ at the nanoscale is unfolding unlocking vital clues enabling the development of more effective retardants. In this direction, the dimensional order of particles in naturally occurring nanoclay materials and their associated properties as composites are gaining increasing attention as important constituents of flame retardants. In this review, we examine closer the compositional importance of intercalated/exfoliated nanoclay networks essential to retardant functionality exploring the chemical significance and discussing underlying mechanisms where possible.

Molecular descriptors of some chemicals that prevent COVID-19

Background: Topological index is numerical molecular descriptor that plays an important role in structureproperty/structure-activity modeling. A large number of works on multiplicative degree based indices has been developed. However, no attention is paid in investigating their chemical significance. Investigation of the chemical importance of such indices is needed. The computation of topological indices for different chemical structures and networks is a current topic of interest in mathematical chemistry. Objective: The objective of the present work is to examine the usefulness of the multiplicative degree based indices in quantitative structure property/activity relationship modeling. In addition, we intend to compute the indices for some antiCOVID-19 chemicals. Materials and Method: The regression analysis for octane data set is performed using MATLAB and Excel to check the predictability of the indices. The sensitivity test is conducted to examine the isomer discrimination ability. To study the indices for chemical structures preventing COVID-19, different combinatorial computation methods are utilized. Results and Discussion: The regression models governing the structural dependence of different properties and activities are derived. The supremacy of the indices as useful molecular descriptors compared to some well-known and most used descriptors is established. Explicit expressions of the indices for hydroxychloroquine, remdesivir (GS-5734) and theaflavin are obtained. Conclusion: As the indices are shown to have remarkable efficiency in quantitative structure property/activity relationship modeling and isomer discrimination, the outcomes can predict different properties and activities of the chemicals under consideration.

Quantum theory of atoms in molecules in condensed charge density space

By leveraging the fundamental doctrine of the quantum theory of atoms in molecules — the partitioning of the electron charge density (ρ) into regions bounded by surfaces of zero flux — we map the gradient field of ρ onto a two-dimensional space called the gradient bundle condensed charge density ([Formula: see text]). The topology of [Formula: see text] appears to correlate with regions of chemical significance in ρ. The bond wedge is defined as the image in ρ of the basin of attraction in [Formula: see text], analogous to the Bader atom, which is the basin of attraction in ρ. A bond bundle is defined as the union of bond wedges that share interatomic surfaces. We show that maxima in [Formula: see text] typically map to bond paths in ρ, though this is not necessarily always true. This observation addresses many of the concerns regarding the chemical significance of bond critical points and bond paths in the quantum theory of atoms in molecules.

Surface-enhanced Raman scattering on a silver-coated TiO2 nanopore core needle biopsy for three dimensional chemical profiling

In vivo analyzing chemical significance under human skin has impinged a formidable challenge upon regular optical methods due to its intrinsic opaque property.

Synthetic Versus Enzymatic Pictet-Spengler Reaction: An Overview

Background: Pictet-Spengler reactions is an irreplaceable part of cyclization reaction leading to the formation of indispensable heterocyclic moieties including imidazole, benzoxazole, pyrrole, indole and others having immense biological and chemical significance. Researchers have explored this reaction using different types of catalysts and reactions conditions (including solvents, acids, etc.) to ensure the better selectivity, less reaction time and high product yields. A total of five Pictet-Spenglerases have been discovered from various sources including plants, animals, fungi, and microbes, and are responsible for the synthesis of various important alkaloids of biological medicinal importance. Objective: The present review is a strenuous effort to assemble information mainly focusing on synthetic as well as biological Pictet-Spengler reactions catalysed by enzymes called Pictet-Spenglerase. Conclusion: In the present review, the recent advances in the PS-mediated synthesis of diverse heterocycles such as tetrahydroisoquinoline, tetrahydro-β-carbolines, tetrahydroimidazopyridines and other fused heterocycles via chemical as well as enzymatic pathways have been covered. The compounds find their scope as medicinal agents for the treatment of cancer, tuberculosis, bacterial infection, leishmanial, etc. The compilation is expected to provide a mechanistic insight to chemists to enhance the reaction condition, yields and another parameter to ensure the safe and inexpensive reaction conditions considering the “Green-Concept” of chemistry.

On Topological Properties of 2-Dimensional Lattices of Carbon Nanotubes

Topological descriptors are the most important numerical quantities in the fields of mathematical chemistry and nanotechnology. These numerical descriptors are based on the topology of the atoms and their bonds (chemical conformation, quaternary structure). Local-valency/degree based topological descriptors/indices are of vital importance due to their specific chemical significance. These numerical invariants are the most successful molecular descriptors in structure-property and structure-activity relationships studies. A nanostructure is an object of intermediate size between molecular and microscopic structures. It is a product derived through engineering at the molecular scale. The most important of these new materials are carbon nanotubes. They have remarkable electronic properties and many other unique characteristics. Carbon nanosheets are 2-dimensional lattices of carbon nanotubes. To compute and study topological indices of nanostructures is a respected problem in nanotechnology. In this paper, degree based topological indices of certain carbon nanosheets are strong-minded. We formulate an important conjecture at the end of this article.

On molecular topological properties of benzenoid structures

The degree-based topological indices correlate certain physicochemical properties such as boiling point, strain energy, and stability, etc., of certain chemical compounds. Among the major classes of topological indices are the distance-based topological indices, degree-based topological indices, and counting-related polynomials and corresponding indices of graphs. Among all of the degree-based indices, namely the first general Zagreb index, general Rndić connectivity index, general sum-connectivity index, atom–bond connectivity index (ABC), and geometric–arithmetic index (GA), are most important due to their chemical significance. In this paper, we compute the first general Zagreb index, general Randić connectivity index, general sum-connectivity index, ABC, GA, ABC4, and GA5 indices of hexagonal parallelogram P(m,n) nanotubes, triangular benzenoid Gn, and zigzag-edge coronoid fused with starphene ZCS(k,l,m) nanotubes by using the line graphs of the subdivision of these chemical graphs.