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Manufacture of Low-temperature NMR insert abd probe: Stereodynamics of Pyrrolidine derivatives

低温核磁共振插入探针的制造：吡咯烷衍生物的立体动力学

基本信息

批准号：
59840011
负责人：
TAKEUCHI Yoshito
金额：
$ 4.16万
依托单位：
The University of Tokyo, The College of Arts & Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1984
资助国家：
日本
起止时间：
1984 至 1986
项目状态：
已结题

项目摘要

Outline of the purpose of this investigation(1) To observe, by means of a combination of dynamic nmr(dnmr) and molecular mechanics(MM) calculations, the rate processes with a relatively low energy barrier involved in a variety of piperidines and pyrrolidines and to determine the thermodynamic parameters of the processes.(2) To modify the probe, and the low-temperature accessories, such as inserts or nitrogen gas generator, of the nmr instrument (FX-90Q) so that the temperature of -150゜C will be obtained. Such a low temperature is essential to accomplish the above mentioned purpose, since the energy processes to be observed are of low barrier such as the inversion of nitrogen or the restricted rotation of longer bonds such as Ge-C.(3) To determine the thermodynamic parameters of 1-aza-8-heterabicyclo[4.3.0]nonanes and germacyclohexanes. The barriers to be observed are of the order of five kcal/ <mol^(-1)> .Outline of the results(1) The modification of instrument enables us to attain -140゜C without difficulty. To attain -150゜C was found difficult. (2) The inversion of deutrated 1-aza-8-heterabicyclo[4.3.0]nonanes as nearly complete, but the temperature was insufficient to observe a genuine freezing. Similarly, no freezing was observed at this temperature for the ring reversal of germacyclohexanes.

（1）通过动态核磁共振（dnmr）和分子力学（MM）计算相结合的方法，观察了各种哌啶和吡咯烷类化合物在较低能垒下的速率过程，并确定了该过程的热力学参数。(2)修改nmr仪器（FX-90 Q）的探头和低温附件，如插入物或氮气发生器，以便获得-150 ℃的温度。这样的低温对于实现上述目的是必要的，因为要观察的能量过程具有低势垒，例如氮的转化或较长键（例如Ge-C）的受限旋转。(3)测定了1-氮杂-8-杂双环[4.3.0]壬烷和锗环己烷的热力学参数。结果概述（1）对仪器的改进使我们能很容易地达到-140 ℃。发现要达到-150 ° C是困难的。(2)氘代1-氮杂-8-杂双环[4.3.0]壬烷的转化几乎完全，但温度不足以观察到真正的冻结。类似地，在该温度下没有观察到大环己烧的环反转的冻结。