二乙胺合三(5-甲基-2-苯并噻唑基)硼烷的晶体结构

标题化合物二乙胺合三（５－甲基－２－苯并噻唑基）硼烷（Ｃ２８Ｈ２９ＢＮ４Ｓ３（Ｍｒ＝５２７．５７）的晶体属于三斜晶系，空间群为Ｐ１，晶胞参数ａ＝０．３９７（８）ｎｍ，ｂ＝１．１７４２（６）ｎｍ，ｃ＝１．３１００（２）ｎｍ，α＝１０４．２９（２）°，β＝９２．９９（３）°，γ＝９８．５８（５）°，Ｖ＝１．３７９０ｎｍ３，Ｚ＝２，Ｄｃ＝１．２７０ｇ／ｃｍ３，μ（ＭｏＫα）＝２．８０４ｃｍ－１．结构的偏离因子Ｒ＝０．０６４８，Ｒｗ＝０．０７３７．结构测定表明，甲基取代基的电子效应导致硼碳键键长的平均化，预示杂环对硼原子的π－电子反馈与胺基氮原子对硼原子的反馈有彼消此长的关系．     

Self-assembly of a (benzothiazolyl)ethenylbenzocrown ether into a sandwich complex and stereoselective [2+2] photocycloaddition

In the presence of Ba²⁺ ions, (benzothiazolyl)ethenylbenzocrown ether forms the stable sandwich complex 2L⋅Ba²⁺ with an unusual structure, in which the benzothiazole fragments are arranged one above the other. Irradiation of the sandwich complex with visible light induces stereoselective [2+2] cycloaddition giving rise to two “head-to-head” isomers of biscrown-cyclobutane. The addition of dibasic dicarboxylic acids that additionally stabilize the sandwich complex in a favorable conformation affects the isomer ratio of the cyclobutanes formed. The conformational equilibria for the sandwich complex and cyclobutanes were studied by ¹H NMR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1524–1533, July, 2005.     

Polarized Ketene Dithioacetals‐Versatile Synthons for Different Heterocycles

The reactivity of polarized ketene dithioacetals to develop a variety of heterocycles under different conditions was studied.