Electronic structure calculations have been used to investigate possible gas-phase decomposition pathways of α-hydroxyalkyl hydroperoxides (HHPs), an important source of tropospheric hydrogen peroxide and carbonyl compounds. The uncatalyzed as well as water- and acid-catalyzed decomposition of multiple HHPs have been examined at the M06-2X/aug-cc-pVTZ level of theory. The calculations indicate ...

The adsorption of a model nerve agent, O,S-dimethyl methylphosphonothiolate (DMPT), on the hydroxylated and unhydroxylated nano-crystalline magnesium oxide surface followed by the nucleophilic attack of ammonia (NH3) is investigated at the M06-2X/6-311++G(d,p) level of theory using the representative cluster models. The geometries of DMPT and NH3 are fully optimized, while the geometry of the o...

For the large and chemically diverse GMTKN55 benchmark suite, we have studied performance of density-corrected density functional theory (HF-DFT), compared to self-consistent DFT, for several pure hybrid GGA meta-GGA exchange-correlation (XC) functionals (PBE, BLYP, TPSS, SCAN) as a function percentage HF exchange in hybrid. The D4 empirical dispersion correction has been added throughout. subs...

The potential for improving the stability of trinitramide (N(NO2)3) by chemical substitution NO2 group has been investigated using Kohn-Sham density functional theory [M06-2X/6-31+G(d,p)] and ab initio quantum chemistry [CBS-QB3]. Monosubstituted analogs are generally found to have a decreased N-NO2 bond dissociation enthalpy (BDE) because increased stabilization N(NO2)X radical intermediate re...

Quantum chemical modeling was used to investigate the electron-donating properties of the amino group in a series of meta- and para-X-substituted anilines (X = NMe2, NH2, OH, OMe, CH3, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, and NO). Different methods (HF, B3LYP, and M06-2X) and basis sets (6-31+G(d,p), 6-311++G(d,p), and aug-cc-pVDZ) were applied and compared with the MP2 approach. The...

The purpose of this work is to have a better understanding of the mechanism of GTP hydrolysis catalyzed by the elongation factor Tu. Two main aspects are being discussed in the literature: the associative or dissociative character of the process and the nature of nucleophile activation. The calculations of the QM subsystem have been done by means of the M06-2X density functional and the split v...

The structures and energetics of two dihydrochalcones (phloretin and its glycoside phlorizin) were examined with density functional theory, using the B3LYP, M06-2X, and LC-ω PBE functionals with both the 6-311G(d,p) and 6-311 + G(d,p) basis sets. Properties connected to antioxidant activity, i.e., bond dissociation enthalpies (BDEs) for OH groups and ionization potentials (IPs), were computed i...

Saddle point properties of three symmetric and one asymmetric hydrogen transfer and the energy of reaction of the asymmetric reactions are investigated in the present work. These reactions were calculated by various density functionals, many of which were developed in recent years, by coupled cluster theory, and by multicoefficient correlation methods based on wave function theory. Instead of c...

This study presents a detailed mechanistic account of the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from polychlorinated diphenyl ethers (PCDEs). It applies the recently developed meta hybrid M06-2X functional and deploys the 2,2'-dichlorodiphenylether (2,2'-DCDE) molecule as a representative model compound for all PCDEs congeners. We find that, ...

Lignin peroxidase (LiP) is an important enzyme for degrading aromatic hydrocarbons not only in nature but also in industry. In the presence of H₂O₂, this enzyme can easily decompose lignin and analogue compounds under mild conditions. In this reaction mechanism, LiP catalyzes the C-C cleavage of a propenyl side chain, being able to produce veratraldehyde (VAD) from 1-(3',4'-dimethoxyphenyl) pro...