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首页> 外文期刊>Israel journal of chemistry >Tautomerization in Condensed Phases and in Isolated Molecules
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Tautomerization in Condensed Phases and in Isolated Molecules

机译：缩合相和分离的分子中的互变异

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We review our recent investigations of systems revealing single or double proton (hydrogen) transfer in the ground or electronically-excited states. The results obtained for condensed phases are compared with the data provided by experiments carried out in the regime of molecular isolation, mainly by using supersonic jet spectroscopy techniques. Both intra- and intermolecular processes have been studied. Four different bi-functional chromophores are discussed, all sharing a common feature of possessing a proton-donating NH group and an acceptor nitrogen atom incorporated into a pyridine or pyrrolene ring. Porphycene and derivatives reveal, when isolated, coherent double hydrogen transfer manifested by vibration-specific tunneling splittings. In condensed phases, tautomerization occurs as a rate process; its dynamics can be probed by techniques using polarized light. Huge dependence of the tautomerization rate on the strength of intramolecular hydrogen bonds has been detected. 2-(2'-pyridyl)pyrrole provides a rare example of a molecule which undergoes both intramolecular excited-state single proton transfer and a solvent-assisted excited-state double proton transfer reaction. Supersonic jet studies allowed us to identify the vibrational modes that enhance the tautomerization. Photoinduced intramolecular proton transfer in 7-(2'-pyridyl)indole is accompanied by twisting of the proton donor and acceptor subunits. The reaction occurs faster in the supersonic beam than in room temperature solutions. 1H-pyrrolo[3,2-h]quinoline forms 1:1 and 1:2 complexes with alcohols and water. The stoichiometries and vibrational structure could be determined for jet-isolated complexes. The 1:1 cyclic, doubly hydrogen-bonded species reveal rapid photoinduced tautomerization both in condensed phases and when isolated in supersonic beams.
机译：我们回顾了我们最近对揭示地面或电子激发状态中单质质子（氢）转移的系统的研究。将用于冷凝相获得的结果与分子分离状态中进行的实验提供的数据进行了比较，主要是通过使用超音速射流光谱技术。已经研究了分子内和分子间过程。讨论了四个不同的双功能发色团，所有这些都有一个共同的特征，即拥有质子的NH组和掺入吡啶或吡咯环中的受体氮原子。斑岩烯和衍生物揭示，当分离时，相干双氢转移表现为振动特异性的隧穿分裂。在冷凝阶段中，互变异是作为速率过程。它的动力学可以通过使用偏振光来探测。互变异率对分子内氢键强度的巨大依赖性已被检测到。 2-（2'-吡啶基）吡咯提供了一个罕见的分子例子，该分子既经历了分子内激发态单质子转移又有溶剂辅助激发态双质子转移反应。超音速射流研究使我们能够确定增强互变异分解的振动模式。光诱导的7-（2'-吡啶基）吲哚中的分子内质子转移伴随着质子供体和受体亚基的扭曲。反应在超音速束中发生的速度比室温溶液中的反应更快。 1H-吡咯并[3,2-H]喹啉形式1：1和1：2与酒精和水的配合物。可以确定用于喷射分离的复合物的化学计量法和振动结构。 1：1循环，双氢键物质揭示了在凝结相中和在超音速束中分离时的快速光诱导的互变异。

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