Monolayer AlC: Mechanical, Thermoelectric, and Promising Sensing Properties for Environmentally Toxic/Nontoxic Oxygen-Containing Gases.

This work investigated the possibility of a monolayer AlC nanosheet as an optimistic sensor for ecologically poisonous/harmless oxygen-containing gases (OCGs), which includes CO, CO, and HO, implementing nonequilibrium Green's function (NEGF) and first-principles computations. The sensing properties of a pure AlC monolayer were explored in this study, including their mechanical and thermoelectric properties. The pristine AlC has a maximum mobility in the armchair direction for the hole carrier of 62797.

Monolayer PC: A promising material for environmentally toxic nitrogen-containing multi gases.

Carbon and its analogous nanomaterials are beneficial for toxic gas sensors since they are used to increase the electrochemically active surface region and improve the transmission of electrons. The present article addresses a detailed investigation on the potential of the monolayer PC compound as a possible sensor material for environmentally toxic nitrogen-containing gases (NCGs), namely NH, NO, and NO. The entire work is carried out under the frameworks of density functional theory, ab-initio molecular dynamics simulations, and non-equilibrium Green's function approaches.

Hydrogen-induced tunable electronic and optical properties of a two-dimensional penta-PtN monolayer.

Most known two-dimensional materials lack a suitable wide-bandgap, and hydrogenation can be effectively utilized to tune the bandgap of some 2D materials. By employing density functional theory calculations, we investigate the effect of hydrogenation on the electronic and optical properties of a recently reported anisotropic penta-Pt2N4 monolayer. The results show that penta-Pt2N4 is thermally and mechanically stable after hydrogenation and also possesses anisotropic Young's modulus and Poisson's ratio.

2D SbC monolayer: A promising material for the recyclable gas sensor for environmentally toxic nitrogen-containing gases (NCGs).

Based on density functional theory investigation, we exposed the potential application of hexagonal SbC nanosheet as highly sensitive material for nitrogen-containing gases (NCGs) NH, NO and NO molecules. Our rigorous simulations show that NH, NO and NO molecules shows physisorption on the SbC nanosheet via vdW DFT-D3 interactions. The calculations were carried out by considering that the monolayer SbC as the sensor material modulated with its electrical conductivity when its surface adsorbs the gas molecules for their various orientations and positions.

Strain-induced band modulation and excellent stability, transport and optical properties of penta-MP (M = Ni, Pd, and Pt) monolayers.

First principle calculations utilizing density functional theory were carried out to investigate the electronic, transport and optical properties of penta-MP (M = Ni, Pd and Pt) monolayer compounds under applied uniaxial and biaxial tensile strains. With an optimum magnitude of applied strain, we found band gap transitions in penta-MP monolayers from zero/narrow to the semiconductor regime, wherein band gaps were noticed to be firmly dependent on the applied uniaxial and biaxial tensile strains. In this study, the PBE approach was used primarily to evaluate electronic properties, from where the identified architectures of penta-MP with maximum obtained bandgaps under respective optimum strains were assessed through the HSE06 method of calculation for better estimation of band gaps and optical properties.

2D PC as a promising thermoelectric material.

In the present article, we report the thermoelectric properties of monolayer PC3 for the first time. The structural, vibrational, electronic and thermoelectric properties of PC3 are investigated in detail using a combination of density functional and Boltzman transport theory, and are compared to the carbon (graphene) and phosphorous (phosphorene) analogues. The results show that the PC3 monolayer is dynamically stable and robust upon oxygen contact as well.

Toxicity of polyhalogenated dibenzo-p-furans in the light of nucleic acid bases interaction.

Quantitative structure-activity relationship (QSAR) investigation utilizing quantum chemical descriptors under density functional theory is performed to predict the toxicity (pEC) of a series of polyhalogenated dibenzo-p-furans (PHDFs). PHDFs are very important concern to the researchers due to their presence and diverse effects in the environment. A successful two parameter QSAR model is developed with a combination of a global descriptor known as charge transfer (ΔN) between toxins and biosystem and a local descriptor as Fukui function (f) for maximum nucleophilic attack at the toxin site.

Structure, electronic, optical and thermodynamic behavior on the polymerization of PMMA: A DFT investigation.

A density functional theory based scrutiny is implemented on the structure, electronic, optical and thermodynamic properties of the Poly (Methyl MethAcrylate) polymers (PMMA or nMMA; n = 1-5). The quantum chemical descriptors, e.g.

Optical activity of Co-porphyrin in the light of IR and Raman spectroscopy: A critical DFT investigation.

A critical investigation on the structure, electronic properties and optical activities of a series of transition metal doped porphyrins (TMP; TM=Fe, Co, Ni) in the light of infrared and Raman spectroscopy is performed, under density functional formalism. The structure and electronic properties are studied in terms of ionization potential, electron affinity, chemical hardness (η), binding energies of the transition metals (BE) etc. The origin of the optical activities, especially the visibly active cobalt porphyrin is addressed through critical study on their infrared and Raman spectra.

Highly Sensitive Bifunctional Probe for Colorimetric Cyanide and Fluorometric HS Detection and Bioimaging: Spontaneous Resolution, Aggregation, and Multicolor Fluorescence of Bisulfide Adduct.

A 4-methylbenzothiazole linked maleimide-based single molecular bifunctional probe 1 has been synthesized for the colorimetric and fluorometric detection of highly competitive HS and cyanide ion in aqueous DMSO media. The probe 1 selectively detected CN under the UV-vis spectroscopy through the rapid appearance of deep pink color. The bright pink color developed due to ICT in the moderately stable cyano substituted enolate intermediate.

Levofloxacin capped Ag-nanoparicles: A new highly selective sensor for cations under joint experimental and DFT investigation.

A very new and alternate function of an antibiotic drug levofloxacin (Lv), as a highly selective, colorimetric turn-OFF/turn-ON chemosensor for metal-ions Hg and Fe, has been reported in this study. An extremely easy, very less time consuming, economical one-pot method of synthesis has been developed for the production of silver nanoparticles (AgNPs). The AgNPs that are stabilized and surface functionalized by Lv.

Toxicity prediction of PHDDs and phenols in the light of nucleic acid bases and DNA base pair interaction.

The applicability of Density Functional Theory (DFT) based descriptors for the development of quantitative structure-toxicity relationships (QSTR) is assessed for two different series of toxic aromatic compounds, viz., polyhalogenated dibenzo-p-dioxins (PHDDs) and phenols (PHs). A series of 20 compounds each for PHDDs and PHs with their experimental toxicities (IC50 and IGC50) is chosen in the present study to develop DFT based efficient quantum chemical parameters (QCPs) for explaining the toxin potential of the considered compounds.

On the ground state of Pd13.

First-principles electronic structure calculations within a gradient corrected density functional formalism have been carried out to investigate the electronic structure and magnetic properties of Pd(13) clusters. It is shown that a bilayer ground-state structure that can be regarded as a relaxed bulk fragment is most compatible with the experimental results from Stern-Gerlach measurements. An icosahedral structure, considered to be the ground state in numerous previous studies, is shown to be around 0.

Bonding, aromaticity, and structure of trigonal dianion metal clusters.

Various isomers of the trigonal dianion metal clusters, X(3)(2-), X = Be, Mg, Ca, and their mono- and disodium complexes are optimized at the B3LYP/6-311+G(d) level. Different conceptual density functional theory based reactivity descriptors as well as the induced magnetic field values are calculated to understand the stability and aromaticity of these systems. Possibility of bond stretch isomerism is explored.

Arsenic toxicity: an atom counting and electrophilicity-based protocol.

The atomic number (Z) and electrophilicity index (omega) have been utilized to explain the toxicity of various alkali and transition-metal ions as well as to predict that of the arsenic ions. The toxicity of two different training sets of arsenic derivatives is described using the global electrophilicity (omega) and number of nonhydrogenic atoms (N (NH)) along with the local philicity (omega(As)+) and the atomic charge (Q (As)) on the arsenic atom. Applying the regression models from the training sets, toxicity of some unknown arsenic derivatives is predicted.

Aromaticity in cyclic alkali clusters.

Density functional calculations on a hexagonal 1D sodium cluster and a 2D potassium cluster show that the M6 (M = Na, K) rings in the chain present in 3D [Na2MoO3L(H2O)2]n (1) and 2D [K2MoO3L(H2O)3]n (2) are aromatic in character according to the nucleus independent chemical shift (NICS) and multicenter bond indices (MCI) values. The NICS values at the center of the Na6 rings and at the cage center of the K6 rings are comparable to the corresponding values of their polyacene analogues in most cases. The stability and reactivity patterns of the M6 rings also follow a similar trend as their organic analogues.

Reactivity, selectivity, and aromaticity of Be3(2-) and its complexes.

The stability, reactivity, and aromaticity of the Be32- dianion and its bimetallic species are investigated. The aromaticity of these systems is analyzed in the light of the DFT-based reactivity descriptors, namely, hardness (eta) and polarizability (alpha), molecular orbital (MO) analysis, and the nucleus-independent chemical shift (NICS). The recently discovered direct Zn-Zn bond is stabilized through the complexation with Be32-, and a new compound [(Be3)2Zn2]2- is reported.

Aromaticity in polyacene analogues of inorganic ring compounds.

The aromaticity in the polyacene analogues of several inorganic ring compounds (BN-acenes, CN-acenes, AlN-acenes, BO-acenes, BS-acenes, and Na6-acenes) is reported here for the first time. Conceptual density functional theory-based reactivity descriptors and the nucleus-independent chemical shift (NICS) values are used in this analysis. The nature of the site selectivity is understood through the charges and the philicities.

Synthesis and structure of 1-D Na6 cluster chain with short Na-Na distance: organic like aromaticity in inorganic metal cluster.

A unique 1-D chain of sodium cluster containing (Na6) rings stabilized by a molybdenum containing metalloligand has been synthesized and characterized and the DFT calculations show striking resemblance in their aromatic behaviour with the corresponding hydrocarbon analogues.

A possible union of chemical bonding, reactivity, and kinetics.

In this communication, we report for the first time the reactivity behavior at the transition state, the connection between the equireactivity configuration and the activation barrier, and a possible principle of reactivity conservation along the reaction paths of typical thermoneutral and exo (endo) thermic reactions.

Local descriptors around a transition state: a link between chemical bonding and reactivity.

In this communication, we report for the first time the possible existence of a point of inflection in the profile of a local reactivity descriptor around the transition state. The saddle point of the given reaction coincides with this inflection point which becomes transparent when two such profiles corresponding to bond making and bond breaking processes respectively intersect at the transition state for the thermoneutral reactions. The corresponding ramification of the Hammond postulate for the exo(endo) thermic reactions is also discussed.