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CrystEngComm

Design and understanding of solid-state and crystalline materials



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CrystEngComm, 2009, 11, 2375 - 2380, DOI: 10.1039/b904838c

Size and temperature dependent encapsulation of tetrahedral anions by a protonated cryptand host

Li-Zi Yang, Yu Li, Long Jiang, Xiao-Long Feng and Tong-Bu Lu

The protonated cryptand L shows both size and temperature dependent encapsulation for tetrahedral ClO4- and H2PO4- anions (L = N[(CH2)2NHCH2(C6H4-p)CH2NH(CH2)2]3N). The crystal structures of perchlorate complex [(H6L)(ClO4)][ClO4]5(H2O)7(CH3CN) (1) and phosphate complex [(H8L)(H2O)3][H2PO4]8(H2O)9 (2) showed that the smaller ClO4- can facilely enter into the cavity of H6L6+, while the larger H2PO4- can not be encapsulated inside the cavity of H6L6+ and H8L8+ at room temperature. Upon heating, however, H2PO4- can be encapsulated into the cavity of H8L8+ to generate a complex of [(H8L)(H2PO4)][H2PO4]7(H2O)18 (3), and the encapsulated H2PO4- can be released by increasing the pH value to 2.

Graphical abstract image for this article (ID: b904838c)