A biscalix[4]arene-based ditopic hard/soft receptor for K⁺/Ag⁺ complexation

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• 作者：Budka ; Jan ; Lhotá ; k ; Pavel ; Stibor ; Ivan ; Michlová ; Veronika ; Sykora ; Jan ; Cisarová ; Ivana
• 刊名：Tetrahedron Letters
• 出版年：2002
• 出版时间：April 8, 2002
• 年：2002
• 卷：43
• 期：15
• 页码：2857-2861
• 全文大小：327 K

文摘

A biscalixarene bearing tert-butylated and de-tert-butylated calix[4]arene unit connected by four ethylenoxy bridges has been prepared. This compound adopts the pinched cone conformation (C_2v symmetry) and hence, is suitably preorganised for Ag⁺ complexation. X-ray crystallography showed that the silver cation (soft) is sandwiched by the two distal coplanar phenyl rings of the de-tert-butylated part of the molecule possessing a η¹ binding mode. The complexation of the K⁺ cation (hard) into the central cavity created by the bridging moieties leads to a change of conformation (C_4v symmetry) and hence, to the complete loss of complexation ability towards the Ag⁺ cation.