Unveiling the chemical kinetics of aminomethanol (NHCHOH): insights into H and O photo-oxidation reactions and formamide dominance.

Aminomethanol is released into the atmosphere through various sources, including biomass burning. In this study, we have expounded the chemical kinetics of aminomethanol in the reaction pathways initiated by the hydroxyl radical ( H) with the aid of //density functional theory (DFT) , coupled-cluster theory (CCSD(T))//hybrid-DFT (M06-2X/6-311++G (3df, 3pd). We have explored various possible directions of the H radical on aminomethanol, as well as the formation of distinct pre-reactive complexes.

Domino Reaction Protocol to Synthesize Benzothiophene-Derived Chemical Entities as Potential Therapeutic Agents.

An efficient synthesis of 3-amino-2-formyl-functionalized benzothiophenes by a domino reaction protocol and their use to synthesize a library of novel scaffolds have been reported. Reactions of ketones and 1,3-diones with these amino aldehyde derivatives formed a series of benzothieno[3,2-]pyridine and 3,4-dihydro-2-benzothiopheno[3,2-]quinolin-1-one, respectively. A plausible mechanism for the formation of fused pyridine derivatives by the Friedlander reaction has been elucidated by density functional theory (DFT) calculations.

Can a single ammonia and water molecule enhance the formation of methanimine under tropospheric conditions?: kinetics of CHNH + O (+NH/HO).

The aminomethyl (•CHNH) radical is generated from the photo-oxidation of methylamine in the troposphere and is an important precursor for new particle formation. The effect of ammonia and water on the gas-phase formation of methanimine (CHNH) from the CHNH + O reaction is not known. Therefore, in this study, the potential energy surfaces for CHNH + O (+NH/HO) were constructed using //DFT, i.

A Novel Quasi-Planar Two-dimensional Carbon Sulfide with Negative Poisson's Ratio and Dirac Fermions.

In the present study, a novel and unconventional two-dimensional (2D) material with Dirac electronic features has been designed using sulflower with the help of density functional theory methods and first principles calculations. This 2D material comprises of hetero atoms (C, S) and belongs to the tetragonal lattice with P /nmm space group. Scrutiny of the results show that the 2D nanosheet exhibits a nanoporous wave-like geometrical structure.

Rational Design of Lewis Base Electron Transport Materials for Improved Interface Property in Inverted Perovskite Solar Cells: A Theoretical Investigation.

Electron transport materials (ETMs) play a vital role in electron extraction and transport at the perovskite/ETM interface of inverted perovskite solar cells (PSCs) and are useful in power conversion efficiency (PCE), which is limited by interface carrier recombination. However, strategies for passivating undercoordinated Pb at the perovskite/ETM interface employing ETMs remain a challenge. In this work, a variety of heteroatoms were used to strengthen the Lewis base property of new ETMs (asymmetrical perylene-diimide), aimed at deactivating non-bonded Pb at the perovskite surface through Lewis acid-base coordination.

Effect of formic acid on O + OH˙CHOH → HCOOH + HO reaction under tropospheric condition: kinetics of and isomers.

Formic acid (HCOOH) is one of the highly abundant acids in the troposphere. It is important in the formation of atmospheric aerosols and impacts the acidity of rainwater. In the present scenario, the model chemistry of HCOOH(FA) sources and sinks is poorly understood.

Synthesis, Anticancer, Antioxidant, Anti-Inflammatory, Antimicrobial Activities, Molecular Docking, and DFT Studies of Sultams Derived from Saccharin.

A series of -substituted saccharins namely 2-(1,1-dioxido-3-oxobenzo[d]isothiazol-2()-yl) acetonitrile () and (alkyl 1,1-dioxido-3-oxobenzo[d]isothiazol-2(3)-yl) acetate (-) were synthesized, in moderate to excellent yields, from commercially available starting materials by two different approaches and their chemical structures were characterized by spectroscopic techniques (H-NMR, C-NMR, IR, and MS). All the synthesized compounds were evaluated for their anti-inflammatory toward IL-6 and TNF-α, antioxidant, as well as their anticancer activities against hepatic cancer cells. In addition, their anti-fungal and antibacterial activities against both Gram-positive and Gram-negative bacteria were tested.

Effect of a single water molecule on ˙CHOH + O reaction under atmospheric and combustion conditions.

The hydroxymethyl (˙CHOH) radical is an important intermediate species in both atmosphere and combustion reaction systems. The rate coefficients for ˙CHOH + O and (˙CHOH + O (+HO)) reactions were calculated using the Rice-Ramsperger-Kassel-Marcus (RRKM)/master equation (ME) simulation and canonical variational transition state theory (CVT) between the temperature range of 200 to 1500 K based on the potential energy surface constructed using CCSD(T)//ωB97XD/6-311++G(3df,3pd). The results show that ˙CHOH + O leads to the formation of CHO and HO at temperatures below 800 K, and goes back to reactants at high temperature (>1000 K).

Effect of ammonia and water molecule on OH + CHOH reaction under tropospheric condition.

The rate coefficients for OH + CHOH and OH + CHOH (+ X) (X = NH, HO) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400 K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CHOH is dominated by the hydrogen atoms abstraction from CH position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies.

Benign Synthesis of Fused-thiazoles with Enone-based Natural Products and Drugs for Lead Discovery.

In an effort to synthesize a library of bioactive molecules, we present an efficient synthesis of fused-thiazole derivatives of natural products and approved drugs by using an environmentally usable solvent, acetic acid, and without any external reagent. Cholestenone, ethisterone, progesterone, and nootkatone-derived epoxyketones have been utilized to synthesize 50 novel compounds. The plausible mechanism of the reaction has been determined by theoretical calculation using M06-2X/6-31+G(d,p).

rate coefficients for reactions of 2,5-dimethylhexyl isomers with O: temperature- and pressure-dependent branching ratios.

Chemical kinetics of O2-addition to alkyl radicals (R), termed first O2-addition in the oxidation mechanism of alkanes, are of central importance to next-generation combustion strategies designed for operations in the low- to intermediate-temperature region (<1000 K). In the present work, stationary points on potential energy surfaces (PES), temperature- and pressure-dependent rate coefficients, and branching fractions of product formation from R + O2 reactions initiated by the addition of molecular oxygen (3O2) to the three alkyl radicals of a branched alkane, 2,5-dimethylhexane, are reported. The stationary points were determined utilizing ab initio/DFT methods and the reaction energies were computed using the composite CBS-QB3 method.

Computational studies on the gas phase reaction of methylenimine (CHNH) with water molecules.

In this work, we used quantum chemical methods and chemical kinetic models to answer the question of whether or not formaldehyde (CHO) and ammonia (NH) can be produced from gas phase hydration of methylenimine (CHNH). The potential energy surfaces (PESs) of CHNH + HO → CHO + NH and CHNH + 2HO → CHO + NH + HO reactions were computed using CCSD(T)/6-311++G(3d,3pd)//M06-2X/6-311++G(3d,3pd) level. The temperature-and pressure-dependent rate constants were calculated using variational transition state theory (VTST), microcanonical variational transition state theory [Formula: see text] and Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) simulations.

Synthesis and Antimicrobial Studies of 4-[3-(3-Fluorophenyl)-4-formyl-1-pyrazol-1-yl]benzoic Acid and 4-[3-(4-Fluorophenyl)-4-formyl-1-pyrazol-1-yl]benzoic Acid as Potent Growth Inhibitors of Drug-Resistant Bacteria.

Microbial resistance to antibiotics is an urgent and worldwide concern. Several pyrazole-derived hydrazones were synthesized by using benign reaction conditions. Several of these molecules are potent growth inhibitors of drug-resistant strains of and with minimum inhibitory concentration values as low as 0.

Theoretical study on the gas phase reaction of CHO + NH: the formation of CHONH, NHCHOH, or CHNH + HO.

The gas phase reaction between CHO and NH is an important reaction in cold interstellar clouds, combustion chemistry and organic chemistry. In this study, the stationary point on the potential energy surfaces (PESs) for the CHO + NH reaction was computed at the CCSD(T)/6-311++G(3df,3pd)//M06-2X/6-311++G(3df,3pd) level. The temperature- and pressure-dependent rate constants were computed using advanced kinetic models, including microcanonical variational transition state theory and Rice-Ramsperger-Kassel-Marcus (RRKM)/master equation (ME) techniques.

Novel photoresponsive cyclicparaphenylenediazenes: structure, strain energy, cis-trans isomerization, and electronic properties.

A series of cis-trans isomers of cyclicparaphenylenediazenes (CPPDs) have been designed to explore their potential applications in solar thermal fuels and photoswitchable devices. In this work, three isomers of cis-trans-[3]CPPD, seven isomers of cis-trans-[4]CPPD, eleven isomers of cis-trans-[5]CPPD, and sixteen isomers of cis-trans-[6]CPPD have been proposed using density functional theory (DFT) at the B3LYP/6-31+G(d,p) level of theory. The stability of these CPPDs has been quantified by the homodesmotic reaction approach.

Hexafluoroisopropanol-Mediated Domino Reaction for the Synthesis of Thiazolo-androstenones: Potent Anticancer Agents.

A cascade reaction of thioamides with 6β-bromoandrostenedione in hexafluoroisopropanol formed substituted thiazolo-androstenones. This is a simple and mild protocol to synthesize novel molecules by using readily available reagents and substrates. Feasibility of the reaction has been rationalized by density functional theory calculations.

Benign Synthesis of Thiazolo-androstenone Derivatives as Potent Anticancer Agents.

An unprecedented reaction of thiourea derivatives with 6β-bromoandrostenedione has been discovered for the formation of aminothiazolo-androstenones via a simple, safer, cascade protocol that enables the syntheses of novel molecules by using readily available reagents. The reaction mechanism of product formation has been rationalized by density functional theory calculations. This benign methodology accentuates a domino protocol deploying a renewable solvent, ethanol, while generating novel compounds that display potent growth inhibitory effects in in vitro studies for several cancer cell lines at submicromolar concentrations.

Hexafluoroisopropanol mediated benign synthesis of 2H-pyrido[1,2-a]pyrimidin-2-ones by using a domino protocol.

Domino strategy has been used for the synthesis of 2H-pyrido[1,2-a]pyrimidin-2-ones. Four sequential reactions: aza-Michael addition, water elimination, intramolecular acyl substitution, and [1,3]-H shift were observed in this domino protocol. Hexafluoroisopropanol is used as a promotor and recyclable solvent in this cascade process.

Catalytic effect of a single water molecule on the OH + CHNH reaction.

In recent work, there has been considerable speculation about the atmospheric reaction of methylenimine (CHNH), because this compound is highly reactive, soluble in water, and sticky, thus posing severe experimental challenges. In this work, we have revisited the kinetics of the OH + CHNH reaction assisted by a single water molecule. The potential energy surfaces (PESs) for the water-assisted OH + CHNH reaction were calculated using the CCSD(T)//BH&HLYP/aug-cc-pVTZ levels of theory.

Predicted Chemical Activation Rate Constants for HO2 + CH2NH: The Dominant Role of a Hydrogen-Bonded Pre-reactive Complex.

The reaction of methanimine (CH2NH) with the hydroperoxy (HO2) radical has been investigated by using a combination of ab initio and density functional theory (CCSD(T)/CBSB7//B3LYP+Dispersion/CBSB7) and master equation calculations based on transition state theory (TST). Variational TST was used to compute both canonical (CVTST) and microcanonical (μVTST) rate constants for barrierless reactions. The title reaction starts with the reversible formation of a cyclic prereactive complex (PRC) that is bound by ∼11 kcal/mol and contains hydrogen bonds to both nitrogen and oxygen.

Comparison of Three Isoelectronic Multiple-Well Reaction Systems: OH + CH2O, OH + CH2CH2, and OH + CH2NH.

Methylenimine (CH2NH) has been predicted to be a product of the atmospheric photo-oxidation of methylamine, but its atmospheric reactions have not been measured. In this paper, we report potential energy surfaces (PESs) and rate constants for OH + CH2NH and its isoelectronic analogues OH + CH2O and OH + CH2CH2, which are more fully understood. The PESs were computed using the BHandHLYP/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ levels of theory.

New and under explored epigenetic modulators in search of new paradigms.

Aberrant regulation of epigenetic pathways causes many diseases including aging, cancer, diabetes, viral pathogenesis, drug addiction etc. and it has been estimated that epigenetic aberrations are at least ten to forty times more frequent in cancers than genetic mutations. Present epigenetic modulators hold great promise for a variety of diseases, and important tools for biological applications but these molecules have many dose limiting toxicities and existing paradigms lack desired efficacy.

Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane.

Product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). Interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperature over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals.

Ab initio investigation of the thermal decomposition of n-butylcyclohexane.

Environmental and energy security concerns have motivated an increased focus on developing clean, efficient combustors, which increasingly relies on insight into the combustion chemistry of fuels. In particular, naphthenes (cycloalkanes and alkylcycloalkanes) are important chemical components of distillate fuels, such as diesel and jet fuels. As such, there is a growing interest in describing napthene reactivity with kinetic mechanisms.