Push-pull 1,3-thiazolium-5-thiolates. Formation via concerted and stepwise pathways, and theoretical evaluation of NLO properties,
作者:David Cantillo、Martín Ávalos、Reyes Babiano、Pedro Cintas、José L. Jiménez、Mark E. Light、Juan C. Palacios、Valentín Rodríguez
DOI:10.1039/c0ob00416b
日期:——
The transformation of münchnones (mesoionic rings featuring the 1,3-oxazolium-5-olate core) into their sulfur counterparts (1,3-thiazolium-5-thiolates) by reaction with CS2, pioneered by Huisgen and his group in the early 1970s, has been re-investigated in detail by means of both experimental and theoretical methods. The synthetic strategy can be tuned to incorporate donor and acceptor groups in appropriate positions. Calculations of molecular hyperpolarizabilities together with orbital topologies evidence that these sulfur-containing heterocycles exhibit nonlinear optical responses, thereby pointing to potential applications of mesoionic structures in the NLO field. From a mechanistic viewpoint, modeling of the whole systems at the B3LYP/6-31G(d) level reveals that concerted and stepwise pathways are operative depending on the substitution pattern of the parent münchnone, which also account for the experimental results.
münchnones(含有1,3-噻唑啉-5-硫类核心的中性离子环)通过与二硫碳(CS2)反应转化为其硫类对应物(1,3-噻唑啉-5-硫酸盐)的过程,最初是由Huisgen及其小组在1970年代初期开创的。现在,该过程已通过实验和理论方法进行了详细再研究。合成策略可以调整,以适当地加入给体和受体基团。分子超极化率的计算结合轨道拓扑表明,这些含硫杂环显示出非线性光学响应,从而指向中性离子结构在非线性光学(NLO)领域的潜在应用。从机制的角度来看,在B3LYP/6-31G(d)水平对整个系统的建模表明,基于母体münchnone的取代模式,协同和逐步反应路径在起作用,这也解释了实验结果。