an azobenzene bridge was introduced into the lower (or smaller) rim of p-tert-butylcalix[8]arene to form 1,5-singly bridged calix[8]arene derivatives, respectively. bridged calix[8]arene of conformationally rigid wereisolated. the stability of the two structures of bridged calix[8]arenes have been compared.the study of organicstructure to form nanoporous structures is a well known in chemistry ...

Crystal engineering has recently emerged as a method of choice for the design and construction of organic as well as metal-organic functional materials. Crystal engineering attempts to establish packing trends in whole families of compounds and seeks to establish connections between structure and function. The utility of crystal engineering has also been expanded to the nanoscience and the deve...

X線 回折 法 に よる結 晶構 造 解 析 は,大 き さ0 .1 ~1mmの 単 結 晶 が あ れ ば ,原 子 の三 次 元 配 列 を 決 定 す る こ とが で き,原 子 間 距 離,結 合 角,配 位 数 な どの化 学 結 合 に 関 す る知 識 が 直 接 得 られ る非 常 に 優 れ た 方法 で あ る。 結 晶構 造 を決 定 す る過 程 は,次 の二 つ の段 階 に分 け られ る。 第1は ,単 結 晶 を 選 んで ワイ セ ンベ ル グ写 真 法 な どに よ って 晶 系,格 子 定 数,空 間 群 を 決 め,比 重 測 定 に よ って 単 位 格 子 内 の 化 学 単 位 数 を 決 定 す る過程 で あ る。 第2は,単 結 晶 のX線 回 折 強 度 か ら各原 子 の座 標 を 決 定 す る過 程 で あ る。 こ の過...

-Thirty two boehmites, synthesized at temperatures ranging from room temperature to 300~ were examined by scanning electron microscopy, transmission electron microscopy, electron diffraction, X-ray powder diffraction, differential thermal analysis, and infrared spectroscopy. The results show that boehmite exhibits a continuous gradation in crystallite size ranging from single octahedral layers ...

An azobenzene bridge was introduced into the lower (or smaller) rim of p-tert-butylcalix[8]arene to form 1,5-singly bridged calix[8]arene derivatives, respectively. Bridged calix[8]arene of conformationally rigid wereisolated. The stability of the two structures of bridged calix[8]arenes have been compared.The study of organicstructure to form nanoporous structures is a well known in chemistry ...

The crystal structure of antimonian asbecasite in an ejectum of hypabyssal origin occurring at Tre Croci near Vetralla, Vico volcanic complex, Roman potassic province, Latium, Italy, has been refined to R = 0.042, and is compared to the original crystal structure determination carried out on the Sb-free asbecasite of hydrothermal metamorphic origin from the type-locality, Cherbandung in Binna v...