Constraining the Conformational Landscape of a Polyether Building Block by Raman Jet Spectroscopy
Constraining the Conformational Landscape of a Polyether Building Block by Raman Jet Spectroscopy
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DOI：
10.1515/zpch-2015-0633
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发表时间：
2015-01-01
影响因子：
2.5
通讯作者：
Suhm, Martin A.
中科院分区：
文献类型：
--
作者：
Bocklitz, Sebastian;Suhm, Martin A.
通过使用聚焦 5-25 W CW 532 nm 辐射探测复合晶种载气膨胀随载气、喷嘴温度和距离的变化，在超音速狭缝射流中对 CH3OCH2CH2OCH3 围绕其三个中心扭转角的碰撞引起的链异构化进行了表征。自发拉曼散射光子被收集并分散至 100 cm(-1)。他们揭示了三种链构象在扩展中的重要贡献。发现外扭转角周围的异构化是可行的，而中心 OCCO 角在大多数膨胀条件下仍然基本保守。光谱结果用于对三种低位构象的能量序列的量子化学预测进行严格评估。这种聚醚结构单元的拉伸全局最小能量结构与主要单分子弛豫路径的统计模型一致。
Collisionally induced chain isomerization of CH3OCH2CH2OCH3 around its three central torsional angles is characterized in a supersonic slit jet by probing compound-seeded carrier gas expansions with focussed 5-25 W cw 532 nm radiation as a function of carrier gas, nozzle temperature and distance. Spontaneously Raman scattered photons are collected and dispersed down to 100 cm(-1). They reveal important contributions from three chain conformations in the expansion. Isomerization around the outer torsional angle is found to be feasible, whereas the central OCCO angle remains largely conserved under most expansion conditions. The spectroscopic results are used for a critical assessment of quantum-chemical predictions for the energy sequence of the three low-lying conformations. The stretched global minimum energy structure of this polyether building block is consistent with a statistical model of the dominant unimolecular relaxation pathways.