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首页> 外文期刊>Journal of Molecular Structure. Theochem: Applications of Theoretical Chemistry to Organic, Inorganic and Biological Problems >Ab initio GB study of Prebiotic synthesis of purine precursors from aquenous hydrogen cyanide:idmerization reaction of HCN in aqueous solution
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Ab initio GB study of Prebiotic synthesis of purine precursors from aquenous hydrogen cyanide:idmerization reaction of HCN in aqueous solution

机译：从头开始GB研究从氰化氢水溶液中合成嘌呤前体的益生元：水溶液中HCN的二聚反应

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摘要

Ab initio MO GB theory which includes the continuum model of solvent effect using generalized Born formula has been applied to the dimerization reaction of HCN in aqueous solution which is the starting step in prebiotic synthesis of purine precursors from aqueous hydrogen cyanide. Three steps considered were: (i) the reaction of HCN and H20 to produce the CN anion, (ii) the reaction of CW with HCN to give the NC—CH=N anion, and (iii) the addition of a proton to the anion to give iminoacetonitrile. The formation of CW ion from HCN in aqueous solution requires 15.1 kcallmol (the experimental value estimated from the dissociation constant of HCN in water is 14.8 kcallmol). The reaction of CN with H~N requires the activation energy of 32.2 kcallmol (MP216-31 + +G**I/HFI6~31 + +G*~) to give the dimer. This barrier height is reduced to 26.1 kcallmol when HCN is associated with H3O~. In the presence of NH3 in aqueous solution, CN is produced easily by the reaction of HCN and NH3 with a low activation energy of 4.3 kcallmol. It was shown that the formation of CN - becomes easier in aminoniacal solution. -and the dimerization occurs efficiently in aqueous solutions which contain NI-I3. ? 2000 Elsevier Science B.V. All rights reserved.
机译：从头算起，MO GB理论（包括使用广义Born公式的溶剂效应的连续模型）已应用于HCN在水溶液中的二聚反应，这是从氰化氢水溶液益生元合成嘌呤前体的起始步骤。考虑了三个步骤：（i）HCN和H20反应生成CN阴离子，（ii）CW与HCN反应生成NC-CH = N阴离子，以及（iii）向质子中添加质子阴离子产生亚氨基乙腈。在水溶液中由HCN形成CW离子需要15.1 kcallmol（根据HCN在水中的解离常数估算的实验值为14.8 kcallmol）。 CN与H〜N的反应需要32.2 kcallmol（MP216-31 + + G ** I / HFI6〜31 + + G *〜）的活化能才能生成二聚体。当HCN与H3O〜缔合时，该势垒高度降低至26.1 kcallmol。在水溶液中存在NH3的情况下，通过HCN和NH3的活化能低至4.3 kcallmol，很容易生成CN。结果表明，在氨基溶液中CN-的形成变得更容易。 -二聚作用在含有NI-1 3的水溶液中有效地发生。 ？ 2000 Elsevier Science B.V.保留所有权利。

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