Vacuum‐ultraviolet circular dichroism of acetylated glucans
Vacuum‐ultraviolet circular dichroism of acetylated glucans
复制标题
乙酰化葡聚糖的真空紫外圆二色性
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
E. S. Stevens
中科院分区：
文献类型：
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作者：
A. Stipanovic;E. S. Stevens
我们测量了一系列含有α-和β-（1→3）、（1→4）和（1→6）键的乙酰化葡聚糖的溶液和薄膜紫外圆二色性。除了先前研究的210 nm带外，我们还观察到190 nm附近的整个π-π* 带;这些带对于所有三乙酸酯都是阴性的，无论其构型和构象如何。170 nm附近的一个谱带显示了（1→3）-和（1→6）-连接的多糖的构型敏感性。对于两种（1→4）-连接的三乙酸酯，条带均为阳性，但当三乙酸纤维素部分脱乙酰化时，170-nm条带变为阴性，从而使相关性完整。三醋酸纤维素薄膜中的正170 nm带比任何其他情况下都要强一个数量级以上，并且在153 nm附近伴随着同样大的负带，这增加了三醋酸纤维素中的二色性来自强激子相互作用的可能性，这些激子相互作用在部分脱乙酰化时被破坏。
We have measured the solution and film vacuum ultraviolet circular dichroism of a series of acetylated glucans containing α‐ and β‐(1→3), (1→4), and (1→6) linkages. In addition to the 210‐nm band studied previously, we observe the entire π‐π* band near 190 nm; these bands are negative for all triacetates regardless of configuration and conformation. A band near 170 nm shows configurational sensitivity for (1→3)‐ and (1→6)‐linked polysaccharides. The band is positive for both (1→4)‐linked triacetates, but when cellulose triacetate is partially deacetylated, the 170‐nm band becomes negative, thus making the correlation complete. The positive 170‐nm band in cellulose triacetate films is more than an order of magnitude more intense than in any other case and, further, is accompanied by an equally large negative band near 153 nm, raising the possibility that the dichroism in the triacetate arises from strong excitonic interactions which are disrupted upon partial deacetylation.