固态富马酸单乙酯在变温1H MAS与CRAMPS研究

富马酸单乙酯(FAME)的单脉冲¹H MAS谱由-高分辨成分与-宽线谱成分组成.高分辨成分可由Hahn回波脉冲序列单独获得.文中通过变温¹H MAS与CRAMPS实验对两组分的性质进行了系统的研究.发现当温度趋于样品的熔点时,其¹H CRAMPS谱可观察到化学位移明显区别的两套谱,它们分别对应于¹H MAS谱的高分辨与宽线组分.实验表明:高分辨成分来自FAME样品的-塑性相,而宽线组分来自通常的刚性相.文中所给出的实验事实充分说明¹H MAS与CRAMPS技术是研究有机塑性固体的强有力的工具.

VARIABLE TEMPERATURE STUDIES OF FUMARIC ACID MONOETHYL ESTER BY SOLID STATE 1H MAS AND 1H CRAMPS SPECTROSCOPIES

The 1H MAS spectrum of fumaric acid monoetbyl ester recorded by a single pulse experiment is composed of a high resolution component and a broadline component.The high resolution component can be well separated from the broadline component using Hahn echo sequence with a long echo time.The properties of both components are investigated by variable temperature 1H MAS and CRAMPS experimentS.Two sets of resonances are observed in the CRAMPS spectrum as the temperature approaches the melting point of the sample.It is confurmed that the high resolution component is produced by a plastic phase in the solid,while the broadline component is generated by the rest of the solid,i.e., the rigid phase.The experimental resultS sufficiently demonstrate that the modern NMR techniques,1H MAS and CRAMPS,are very useful tools for the studying of plaStic organic solids because of their enhanced spectal resolution.