Monte Carlo–Quantum Mechanics Study of Magnetic Properties of Hydrogen Peroxide in Liquid Water

Abstract

A theoretical study of magnetic properties of hydrogen peroxide in water has been carried out by means of Monte Carlo simulation and quantum mechanics calculations. The solvent effects were evaluated in supermolecular structures generated by simulations in the NPT ensemble. The solute-solvent structure was analyzed in terms of radial distribution functions, and the solute-solvent hydrogen bonds were identified with geometric and energetic criteria. Approximately three water molecules are hydrogen bonded to H2O2 (0.6 and 0.8 in each hydrogen and oxygen atom, respectively, of the H2O2). Although, on average, both hydroxyls of the peroxide are equivalent, the distribution of hydrogen-bonded water molecules is highly asymmetric. Analyzing the statistics of the hydrogen bonds, we identify that only 34% of the configurations give symmetric distributions around the two hydroxyls of the H2O2 simultaneously. The magnetic shieldings and the indirect spin-spin coupling constants were calculated at the B3LYP/aug-cc-pVTZ and aug-cc-pVTZ-J computational level. We find that the solvent shields the oxygen and unshields the hydrogen atoms of the peroxide (+5.5 and -2.9 ppm, respectively), with large fluctuation from configuration to configuration in the oxygen case, an effect largely accounted for in terms of a single hydrogen bond with H2O2 as the proton donor. The most sensitive coupling in the presence of the solvent is observed to be the one-bond J(O,H).

A Simple Additive Potential Model for Simulating Hydrogen Peroxide in Chemical and Biological Systems

“…Integration up to 2.45 Å yields 1.5 H w per O p , consistent with the calculated three water molecules in close vicinity to H 2 O 2 . The peak at 1.95 Å is within the range (1.85–2.1 Å) reported from previous MD, Monte Carlo, and QM/MM simulations. , Also, previous investigations found that each O p acts as a H-bond acceptor to an average of 1.0 or 1.4 H 2 O molecules.…”

“…Integration up to the minima at 3.15 and 4.15 Å yields 3.0 and 9.4 water molecules in the micro and entire first hydration shells of H 2 O 2 , respectively. In comparison, a Monte Carlo simulation on a single H 2 O 2 molecule in 300 water molecules found twice as many water molecules in the micro (6) and entire first solvation (17) shells of H 2 O 2 , and combined quantum mechanics and molecular mechanics (QM/MM) simulations reveals six water molecules in the entire first solvation shell of H 2 O 2 …”

“…Various theoretical studies have been carried out in the gas phase on the H 2 O 2 monomer, − H 2 O 2 clusters, ,,, and H 2 O 2 –H 2 O clusters. − However, only a few conformers have been reported for these clusters, and complexes between H 2 O with more than one H 2 O 2 have not been reported to date.…”

Optimization and benchmarking of a perturbative Metropolis Monte Carlo quantum mechanics/molecular mechanics program

“…This is an excellent agreement which shows that donating and accepting bonds-which pose a very different requirement to QM/MM approaches-can be equally well described. Recent classical simulations 54 show a much larger deviation but reproduce qualitatively the first two peaks. TABLE II.…”

A Kinetic Investigation of Regioselective Solvation of a Solvatochromic Dye in Aqueous Alcohols

“…1.8 × 10 8 MC steps. After this process, a set of configurations with less than 10% of statistical correlation were selected by using the interval of statistical correlation from the autocorrelation function of the energy . To take into account the structure modulation of the solute by the binary solvent mixture, one of the obtained 20 orthogonal configurations was chosen and an ONIOM calculation performed with it, considering solute 2 surrounded by all solvent molecules comprising the first and second solvation layers.…”