过渡态

Promoted by metal dysprosium, aldehydes and ketones could react smoothly with propargyl bromide to afford the corresponding homopropargylic alcohols in good to excellent yields, and no allenic alcohol s were found.

当用苯基炔丙基溴代替炔丙基溴与醛、酮反应时，主要得到了相应的连二烯醇，而没有发现高快丙醇的存在，由此提出了六元环过渡态的反应机理

The introduction of cheap protonic acids can accelerate the formation of an active enanmine intermediate and stabilize the transition state by hydrogen bonding. Consequently, catalytic activity and enantioselectivity of the catalysis system are remarkably increased.

价廉易得的质子酸的引入不仅可促进活性中间体烯胺的生成，并可通过形成的氢键稳定反应的过渡态，从而显著提高该催化体系的催化活性和立体选择性。

In this paper,the rate constant and equilibrium constant of the crack reaction of methyl silicane were obtained with the transition state theory and quantum chemistry calculation.

本文采用过渡态理论和量子化学计算方法，首次计算得到了甲硅烷裂解反应的速率常数和平衡常数，并对结果进行了讨论。

The transition states of ring-breaking and of N2 losing during the thermal decomposition of a series of 5-substituted–1H and –2H tetrazole derivatives have been obtained.

求得了系列5-取代-1H四唑和5-取代-2H四唑的热解开环和失N2两个基元反应的过渡态。

The theoretical properties of BTATz were estimated by a B3LYP method based on 6-31G basis set. The stable geometric configuration and bond order were obtained. The vibrational frequencies, IR spectrum and thermodynamics properties under different temperatures were obtained from vibrational analysis, and the relationship between temperature and thermodynamics properties was deducted. Pyrolysis mechanism of BTATz was discussed, and the transition state and activation energy of ring opening reaction of the tetrazole were deducted.

用B3LYP方法，在6-31G基组水平上对其性能进行了计算，得到了其稳定的几何构型和键级；在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质，并得到了温度对热力学性能影响的关系式；探讨了其热解机理，推断出四唑环开环时的过渡态和活化能。

The mechanism of redistribution of trichloromethyl and chlorotrimethyl silane catalyzed by ZnCl2 has been obtained by calculation.

通过计算，得出了ZnCl2催化的一甲基三氯硅烷和三甲基氯硅烷歧化反应的机理，得出了IRC曲线和过渡态的虚振动模式。

However, their transition states are delocalized and bishomoaromatic.

它们的过渡态是离域双同芳香性的。

The reults show that the recrossing and tunneling effects exist and the corrections by means of CVT method and small curvature approximation method are efficient respectively.

结果表明，反应存在返回效应和隧道效应，反应途径的曲率对隧道效应影响较大，用变分过渡态方法和小曲率近似方法分别进行校正是有效的。

In order to study the aldol condensation of 2.15-hexadecanedione on the surface of aluminium, the intermolecular condensation mechanism of acetone occurring on aluminum was simulated by using semi-empirical AM1 method embodied in MOPAC 6.0 program package. The optimized structures and geometry parameters of 5 transition complexes and 4 intermediates were given.First, 2 molecules of acetone coordinated with aluminum by electrostatic attraction.One atom of hydrogen of acetone migrated to aluminum because of t...

为了研究2，15－十六烷二酮在氧化铝表面的环合机理，选择小分子丙酮为模型化合物，用量子化学半经验AM1方法研究双分子丙酮在氧化铝表面的醛醇缩合机理，给出了反应过程中的5个过渡态和4个中间体的结构和几何参数，该催化反应可以认为是氧化铝分子与两分子丙酮分子发生静电络合作用，然后借助氧原子的负电荷导致脱氢并实现缩合，根据中间体的能量变化，推测有较稳定的铝复合物生成。

The transition state theory approach to cis-trans isomerization in substituted disilenes is presented.

本文介绍了过渡态理论对双键取代物顺反异构化过程的处理方法。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失