H_2CN自由基异构体在前生物分子合成中的可能作用  

POTENTIAL ROLE OF H_2CN RADICALS IN PREBIOTIC SYNTHESIS

作　　者：戚生初[1] 王德民[1] 韩宗沾 孙丕举 

机构地区：[1]北京大学,北京100871

出　　处：《辐射研究与辐射工艺学报》1992年第4期214-219,共6页Journal of Radiation Research and Radiation Processing

摘　　要：用量子化学从头计算法研究了HCN、HNC分子与H原子和电子加成生成的H_2CN自由基异构体的最低总能量构象和净电荷分布。计算结果表明,存在三种可能的H_2CN自由基异构体,即H_2CN(Ⅰ),H_2CN(Ⅱ)和H_2CN(Ⅲ),它们的相对稳定性为(Ⅰ)>(Ⅲ)>(Ⅱ)。根据计算和对反应(1)和反应(2)热化学估算结果。对H_2CN自由基在前生物有机合成中的作用进行了初步讨论,提出了H_2CN(Ⅲ)自由基是合成氨基酸的重要中间物的假设。结果还表明,在某些特殊条件下(如大气放电)HNC分子也是生命分子进化链中的一个重要中间物。Using ab initio method, the minimum energy conformations and netcharge distribution have been studied for H_2CN radical isomers formed by addition ofa H atom (or an electron) to HCN (or HNC) molecule. Calculations show that thereare three possib1e isotners, namely H_2CN(Ⅰ), H_2CN(Ⅱ) and H_2CN(Ⅲ). The orderof relative stability is (Ⅰ)>(Ⅱ)>(Ⅲ). Frotn quantum chemical study and the esti-mations in thermochemistry for the reactions (1) and (2), the possible role of H_2CNradicals in prebiotic organic syntbesis has been discussed and it has been proposed thatH_2CN(Ⅲ) radical is an important intermediate to synthesize amino acids. The results,show that HNC is also an itnportant product in the evolution chain of biomoleculesunder some special conditions, such as the electric discharge for atmosphere.

关 键 词：HCN HNC 氨基酸 游离基 异构体 

分 类 号：Q506[生物学—生物化学]