Low-Temperature FTIR Spectroscopic and Theoretical Study on an Energetic Nitroimine:  Dinitroammeline (DNAM)

Simões, Pedro; Reva, Igor; Pedroso, Fiona L.; Fausto, Rui; Portugal, António

doi:10.1021/jp711153g

Cited by 9 publications

(4 citation statements)

References 70 publications

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“…Geometry optimizations and vibrational frequency calculations were carried out at the B3LYP/6-31++G** level. The performance of the B3LYP functional in describing hydrogen-bonding structures, − electron-attachment-induced proton transfer, − and excess electron binding energies has been verified and, therefore, is suitable for this study. The natures of the stationary points were confirmed by vibrational frequency analyses, and the vibrational motions of the imaginary modes for the transition states were further checked with a graphical program to ensure that they connected the proper reactants and products (Figures S6–S9, Supporting Information).…”

Section: Methodsmentioning

confidence: 98%

Theoretical Study of the Protonation of the One-Electron-Reduced Guanine–Cytosine Base Pair by Water

et al. 2013

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Prototropic equilibria in ionized DNA play an important role in charge transport and radiation damage of DNA and, therefore, continue to attract considerable attention. Although it is well-established that electron attachment will induce an interbase proton transfer from N1 of guanine (G) to N3 of cytosine (C), the question of whether the surrounding water in the major and minor grooves can protonate the one-electron-reduced G:C base pair still remains open. In this work, density functional theory (DFT) calculations were employed to investigate the energetics and mechanism for the protonation of the one-electron-reduced G:C base pair by water. Through the calculations of thermochemical cycles, the protonation free energies were estimated to be in the range of 11.6-14.2 kcal/mol. The calculations for the models of C(•-)(H(2)O)(8) and G(-H1)(-)(H(2)O)(16), which were used to simulate the detailed processes of protonation by water before and after the interbase proton transfer, respectively, revealed that the protonation proceeds through a concerted double proton transfer involving the water molecules in the first and second hydration shells. Comparing the present results with the rates of interbase proton transfer and charge transfer along DNA suggests that protonation on the C(•-) moiety is not competitive with interbase proton transfer, but the possibility of protonation on the G(-H1)(-) moiety after interbase proton transfer cannot be excluded. Electronic-excited-state calculations were also carried out by the time-dependent DFT approach. This information is valuable for experimental identification in the future.

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Section: Methodsmentioning

confidence: 98%

Theoretical Study of the Protonation of the One-Electron-Reduced Guanine–Cytosine Base Pair by Water

et al. 2013

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“…As presented in Figure S9, the absorption peaks around 1602, 1594, and 1585 cm –1 attributed to the stretching vibration of Azo group in PA , PB , and PC chains became obvious stronger along with the reaction time, respectively. Simultaneously, the nitro absorption around 1342, 1334, and 1350 cm –1 became weaker along with the reaction time, which leveled off after 8 h. The weaker nitro absorption peaks are ascribed to the stretching vibration of nitro groups in PA , PB , and PC chain ends.…”

Section: Resultsmentioning

confidence: 94%

A Straightforward Protocol for the Highly Efficient Preparation of Main-Chain Azo Polymers Directly from Bisnitroaromatic Compounds by the Photocatalytic Process

et al. 2015

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A novel strategy for the synthesis of main-chain Azo polymers directly from bisnitroaromatic compounds by the photocatalytic process has been achieved under mild conditions. This approach avoids the tedious synthesis of Azo monomers and proceeds with a high monomer conversion (∼100%) and excellent selectivity (∼100%) but without generating a significant amount of inorganic wastes and impurities (Cu 2+ or azoxy groups) existing in main-chain Azo polymers compared to previous methods. The polymerization was monitored by UV−vis, FT-IR, and MALDI-TOF-MS, indicating that the reaction process proceeded with formation of the azoxy repeating units from the corresponding bisnitroaromatic monomers and the reduction of corresponding azoxy repeating units to the azo repeating units. Furthermore, the recyclable heterogeneous photocatalysts represent an attractive green process for production of main-chain Azo polymers.

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“…The Becke's three-parameter hybrid functional B3LYP was used in conjunction with the 6-31+G* basis set throughout this work. The B3LYP functional, which is the most popular one in the chemistry community, has been demonstrated to be suitable for predicting hydrogen-bonding structures, [37][38][39][40][41][42][43][44][45] electron-attachment induced proton transfer, [20][21][22][23][24][25][26][27][28][29][30] and excesselectron binding energies, 46 therefore, is particularly suitable for the present study. Geometry optimizations were performed without any geometry constraints.…”

Section: Methodsmentioning

confidence: 99%

Microhydration of 9-methylguanine:1-methylcytosinebase pair and its radical anion: a density functional theory study

Chen

Hsu

Kao

2010

Phys. Chem. Chem. Phys.

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In this study, we present density functional theory calculations on the properties of proton transfer and electron binding in isolated, mono-, di-, and pentahydrated 9-methylguanine:1-methylcytosine (mG:mC) base pair radical anions. It was found that the proton transfer in mG:mC(*-) is coupled to the interbase propeller-twisting and stretching motions, which cooperatively shorten the proton-transfer distance. Without the propeller-twisting motion, the interbase stretching will be hindered and the proton-transfer distance will become somewhat longer, which in turn, results in rising of the kinetic barrier for proton transfer. The monohydration can assist or resist the proton-transfer reaction, depending on the hydration sites. Inclusion of five water molecules in the first hydration shell around mG:mC(*-) only moderately lowers the proton-transfer barrier from 3.80 to 3.01 kcal mol(-1) and the reaction energy from -3.16 to -6.40 kcal mol(-1) due to the cancellation between opposite influences of H(2)O molecules. A further consideration of bulk hydration using a polarizable continuum model does not affect the proton-transfer energetics. In contrast, both the first hydration shell and bulk hydration were found to play important roles in stabilizing the excess electron in mG:mC; the adiabatic electron affinity of mG:mC increases from 0.302 to 0.645 eV upon inclusion of five water molecules in the first hydration shell, and further increases to 1.813 eV when the bulk hydration is considered. We noticed that the water molecule can enhance electron binding by direct interaction with the nucleobase that accommodates excess electron or through the indirect effect of tuning interbase hydrogen bonds. In addition, the microhydration effects on proton transfer and electron binding were found to be approximately additive.

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Low-Temperature FTIR Spectroscopic and Theoretical Study on an Energetic Nitroimine: Dinitroammeline (DNAM)

Cited by 9 publications

References 70 publications

Theoretical Study of the Protonation of the One-Electron-Reduced Guanine–Cytosine Base Pair by Water

Theoretical Study of the Protonation of the One-Electron-Reduced Guanine–Cytosine Base Pair by Water

A Straightforward Protocol for the Highly Efficient Preparation of Main-Chain Azo Polymers Directly from Bisnitroaromatic Compounds by the Photocatalytic Process

Microhydration of 9-methylguanine:1-methylcytosinebase pair and its radical anion: a density functional theory study

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