Theoretical Investigation on the Effect of Different Nitrogen Donors on Intramolecular Se⋅⋅⋅N Interactions

Sarma, Bani Kanta; Mugesh, Govindasamy

doi:10.1002/cphc.200900332

Cited by 31 publications

(21 citation statements)

References 79 publications

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“…[24][25][26][27] The geometries of diselenides 3a, 6 and 11 were fully optimized at the B3LYP/6-311+G(d) level of theory (see Table S1-S6 for optimized geometries and coordinates in the Supporting Information).…”

Section: Dft Calculationsmentioning

confidence: 99%

Effect of a Bromo Substituent on the Glutathione Peroxidase Activity of a Pyridoxine-like Diselenide

et al. 2015

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In search for better mimics of the glutathione peroxidase enzymes, pyridoxine-like diselenides 6 and 11, carrying a 6-bromo substituent, were prepared. Reaction of 2,6-dibromo-3-pyridinol 5 with sodium diselenide provided 6 via aromatic nucleophilic substitution of the 2-bromo substituent. LiAlH4 caused reduction of all four ester groups and returned 11 after acidic workup. The X-ray structure of 6 showed that the dipyridyl diselenide moiety was kept in an almost planar, transoid conformation. According to NBO-analysis, this was due to weak intramolecular Se···O (1.1 kcal/mol) and Se···N-interactions (2.5 kcal/mol). That the 6-bromo substituent increased the positive charge on selenium was confirmed by NPA-analysis and seen in calculated and observed (77)Se NMR-shifts. Diselenide 6 showed a more than 3-fold higher reactivity than the corresponding des-bromo compound 3a and ebselen when evaluated in the coupled reductase assay. Experiments followed for longer time (2 h) confirmed that diselenide 6 is a better GPx-catalyst than 11. On the basis of (77)Se-NMR experiments, a catalytic mechanism for diselenide 6 was proposed involving selenol, selenosulfide and seleninic acid intermediates. At low concentration (10 μM) where it showed only minimal toxicity, it could scavenge ROS produced by MNC- and PMNC-cells more efficiently than Trolox.

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Section: Dft Calculationsmentioning

confidence: 99%

Effect of a Bromo Substituent on the Glutathione Peroxidase Activity of a Pyridoxine-like Diselenide

et al. 2015

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“…NBO theory has proven an available method for analyzing energy variation of electron transferring between occupied and unoccupied orbitals . Delocalization interactions of the electron density, that is donor–acceptor interactions, can be investigated using the secondary perturbation stabilization energy (Δ E 2 ), which can be expressed as:

Δ E^{2} = q_{i} \times (F^{2}_{(i, j)} / ε_{j} - ε_{i})

…”

Section: Resultsmentioning

confidence: 99%

“…NBO theory has proven an available method for analyzing energy variation of electron transferring between occupied and unoccupied orbitals. [52,53] Delocalization interactions of the electron density, that is donor-acceptor interactions, can be investigated using the secondary perturbation stabilization energy (DE 2 ), [54] which can be expressed as: Where i and j are the donor and acceptor orbital, respectively, q i is the donor orbital occupancy, e i and e j are the diagonal elements (orbital energy), and F is the NBO Fock matrix elements. Table 8 lists the NBO analysis results of four CL-20/NQ composite structures.…”

Section: Natural Bond Orbitalmentioning

confidence: 99%

Molecular dynamics simulation and density functional theory insight into the cocrystal explosive of hexaazaisowurtzitane/nitroguanidine

Ding

Gou

Ren

et al. 2015

Int J of Quantum Chemistry

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Theoretical methods involving molecular dynamics (MD) simulation and density functional theory were performed to investigate the different molecular ratios, mechanical Properties, structure, trigger bond, and intermolecular interaction of hexaazaisowurtzitane (CL-20)/nitroguanidine (NQ) cocrystal explosive. Results of MD simulation show that CL-20 and NQ packed in ratios of 1:1 present the larger binding energy and better mechanical properties than any other molecular ratios, which indicates 1:1 cocrystal can form the stable crystal structure. Shorter length and larger dissociation energy of trigger bond in composite structure than in isolated CL-20 component suggests that the cocrystal may exhibit less sensitive than CL-20. Analyses of atoms in molecules, reduced density gradient, and natural bond orbital confirm that intermolecular interactions are mainly derived from a series of weak hydrogen bond and strong vdW forces, involving of NHÁÁÁO, CHÁÁÁO, CHÁÁÁN, OÁÁÁN, and OÁÁÁO. Additionally, composite structures of 2 and 3 bringing us more attractive performance will act as a key role in constructing of CL-20/NQ cocrystal explosive.

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“…To compliment the experimental results obtained from pulse radiolysis, energetics for the possible reactionp athways during the COH radicalreaction with SeROH was calculated by employing quantum chemical calculations at the B3LYP/6-31 + G(d,p) level (Becke nonlocal model and Lee-Yang-Parre xchange-correlationf unctionals). [32,33] Optimized ground-stateg eometry of SeROH belongs to the C1 point group and did not show any interaction between Se and the oxygen atom of the hydroxyl group. In all SeROHc ompounds,t he highest occupied molecular orbital( HOMO) was found to be localized on the selenium atom;t herefore an electrophile like the COH radicalw ould react mainly on the Se atom.…”

Section: Quantum Chemicalc Alculationsmentioning

confidence: 96%

Effect of Molecular Interactions on Electron‐Transfer and Antioxidant Activity of Bis(alkanol)selenides: A Radiation Chemical Study

Kumar

Singh

Phadnis

et al. 2016

Chemistry A European J

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Understanding electron-transfer processes is crucial for developing organoselenium compounds as antioxidants and anti-inflammatory agents. To find new redox-active selenium antioxidants, we have investigated one-electron-transfer reactions between hydroxyl ((.) OH) radical and three bis(alkanol)selenides (SeROH) of varying alkyl chain length, using nanosecond pulse radiolysis. (.) OH radical reacts with SeROH to form radical adduct, which is converted primarily into a dimer radical cation (>Se∴Se<)(+) and α-{bis(hydroxyl alkyl)}-selenomethine radical along with a minor quantity of an intramolecularly stabilized radical cation. Some of these radicals have been subsequently converted to their corresponding selenoxide, and formaldehyde. Estimated yield of these products showed alkyl chain length dependency and correlated well with their antioxidant ability. Quantum chemical calculations suggested that compounds that formed more stable (>Se∴Se<)(+) , produced higher selenoxide and lower formaldehyde. Comparing these results with those for sulfur analogues confirmed for the first time the distinctive role of selenium in making such compounds better antioxidants.

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Theoretical Investigation on the Effect of Different Nitrogen Donors on Intramolecular Se⋅⋅⋅N Interactions

Cited by 31 publications

References 79 publications

Effect of a Bromo Substituent on the Glutathione Peroxidase Activity of a Pyridoxine-like Diselenide

Effect of a Bromo Substituent on the Glutathione Peroxidase Activity of a Pyridoxine-like Diselenide

Molecular dynamics simulation and density functional theory insight into the cocrystal explosive of hexaazaisowurtzitane/nitroguanidine

Effect of Molecular Interactions on Electron‐Transfer and Antioxidant Activity of Bis(alkanol)selenides: A Radiation Chemical Study

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