Anion binding by meta ureido-substituted thiacalix[4]arenes

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• 作者：Ond?ej  ; Kundr&aacute ; t^a ; V&aacute ; clav  ; Eigner^b ; Petra  ; Cu?í ; nov&aacute ; ^c ; Jan  ; Kroupa^a ; Pavel  ; Lhot&aacute ; k^a ;   ; ^{pavel.lhotak@vscht.cz} ;   ; ^{lhotakp@vscht.cz}
• 关键词：Calixarene ; meta-Nitration ; Recognition ; Anion binding ; X-ray crystallography
• 刊名：Tetrahedron
• 出版年：2011
• 出版时间：28 October 2011
• 年：2011
• 卷：67
• 期：43
• 页码：8367-8372
• 全文大小：641 K

文摘

The regioselective nitration of 25,26,27,28-tetrapropoxythiacalix[4]arene (1,3-alternate) led to the formation of mono- and dinitro derivatives bearing NO₂ groups in the meta positions at the same side of the molecule. Their reduction and subsequent condensation with arylisocyanates gave the new types of anion receptors with a so far unknown meta-substitution pattern. In a highly HB-competitive solvent like DMSO, the novel ligands showed good complexation abilities. Moreover, as can be documented by higher complexation constants, achiral receptors 9a, 9b are better preorganized for anion binding than corresponding stereoisomers 10a, 10b. Our results indicate that anion receptors based on meta-substituted thiacalixarenes possess complexation abilities fully comparable with common para-substituted analogues.