Journal ArticleDOI
Structures of the X-Y-NO molecules and homolytic dissociation energies of the Y-NO bonds (Y = C, N, O, S)
TLDR
In this paper, high-level theoretical methods (UB3LYP/6-311++g(2df,p), RMP2/6 -311++G(d,p, CBS-4M), CBS-Q, and G3) were used to study the structures and bond dissociation energies (BDE) of the X-Y-NO molecules.Abstract:
High-level theoretical methods (UB3LYP/6-311++g(2df,p), RMP2/6-311++g(d,p), CBS-4M, CBS-Q, and G3) were used to study the structures and bond dissociation energies (BDE) of the X-Y-NO molecules. The data were used to evaluate the previous experimental and theoretical results. It was found that the syn conformation is favored by CH 3 -Y-NO, C 2 H 5 -Y-NO, and CH 3 O-Y-NO (Y = C, N, O, S), whereas the anti conformation is favored by CH 3 CO-Y-NO and Ph-Y-NO (Y = C, N, O). For Ph-S-NO, the syn conformation is preferred because of the long S-N bond. When X is an alkyl substituent, the Y-NO BDEs increase in the order X-S-NO (∼30 kcal/mol) < X-CH 2 -NO (∼40 kcal/mol) < X-O-NO (∼43 kcal/ mol) < X-NH-NO (48 kcal/mol). When X is an aromatic substituent, the Y-NO BDEs increase in the order X-O-NO (∼21 kcal/mol) < X-S-NO (26 kcal/mol) < X-CH 2 -NO (∼30 kcal/mol) < X-NH-NO (∼35 kcal/mol). The solvent effects of acetonitrile on the free energy change of C-NO and N-NO homolysis are significant, which are about 3-5 kcal/mol. The solvent effects of acetonitrile on the free energy change of O-NO and S-NO homolysis are relatively small, which are about 1-2 kcal/mol. Finally, we found that the remote substituent effects on C-NO, N-NO, O-NO, and S-NO BDEs have ρ + values of -0.4∼-0.9, 1.7-1.8, 3.2-3.9, and 1.2-1.7 kcal/mol. These values are significantly different from those on the C-H (0.4-0.6 kcal/mol), N-H (3.4-4.6 kcal/mol), O-H (4.1-5.7 kcal/mol), and S-H (2.0-3.8 kcal/ mol) BDEs. Therefore, the ground effects are important for the net substituent effects on BDEs.read more
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Protein S-Nitrosylation: Determinants of Specificity and Enzymatic Regulation of S-Nitrosothiol-Based Signaling.
TL;DR: To elucidate the operation and consequences of S-nitrosylation in cellular contexts, studies should consider the roles of SNO-proteins as both targets and transducers of S, functioning according to enzymatically governed equilibria.
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Assessment of experimental bond dissociation energies using composite ab initio methods and evaluation of the performances of density functional methods in the calculation of bond dissociation energies.
TL;DR: It was found that among the examined compounds 161 experimental BDEs are valid because the standard deviation between the experimental and theoretical values for them is only 8.6 kJ/mol, and the DFT methods were more reliable for relative BDE calculations than for absolute BDE Calculations.
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Structure and stability of HSNO, the simplest S-nitrosothiol
TL;DR: Previous quantum-chemical data on RSNOs are reexamined based on the new insight into the SNO electronic structure obtained from the present high-level calculations on HSNO, indicating that the electronic structure of the SNo group possesses multireference character.
Journal ArticleDOI
An Assessment of Theoretical Methods for the Calculation of Accurate Structures and SN Bond Dissociation Energies of S-Nitrosothiols (RSNOs)
Cristina Baciu,James W. Gauld +1 more
TL;DR: In this paper, the ability of conventional electron correlation (MP2 and QCISD) and density functional theory (B3LYP and B3P86) methods to provide accurate and reliable optimized structures, and homolytic S−N bond dissociation energies (BDEs), for a range of S-nitrosothiols (RSNOs) has been investigated.
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Anion-Induced Assembly of Five-Coordinated Mercury(II) Complexes and Density Functional Theory Calculations to Study Bond Dissociation Energies of Long Hg—N Bonds
Hongping Zhou,Xiaoping Gan,Xian-Lei Li,Zhaodi Liu,Wen-Qian Geng,Fei-Xia Zhou,Wei-Zai Ke,Peng Wang,Lin Kong,Fu-Ying Hao,Jieying Wu,Yupeng Tian +11 more
TL;DR: A series of new five-coordinated mercury(ΙΙ) coordination complexes have been synthesized by self-assembling the flexible ligand 2,4,6-tri(pyrazole-1-yl)-1,3,5-triazine (TpzT) with HgX2 (X = SCN, I, Br, Cl).
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