Controlled Aggregation of Multiple Guanidinium Ions through a Hydrogen‐Bonded Network Assembly with Deprotonated Forms of Kemp’s Triacid |
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| Authors: | Jie Han Dr Shuang‐Quan Zang Dr Thomas?C?W Mak Prof?Dr |
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| Institution: | Department of Chemistry and Center of Novel Functional Molecules, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR (P.R. China), Fax: (+852)?2603‐5057 |
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| Abstract: | A series of five complexes that incorporate the guanidinium ion and various deprotonated forms of Kemp’s triacid (H3KTA) have been synthesized and characterized by single‐crystal X‐ray analysis. The complex C(NH2)3+] ? H2KTA?] ( 1 ) exhibits a sinusoidal layer structure with a centrosymmetric pseudo‐rosette motif composed of two ion pairs. The fully deprotonated Kemp’s triacid moiety in 3 C(NH2)3+] ? KTA3?] ( 2 ) forms a record number of eighteen acceptor hydrogen bonds, thus leading to a closely knit three‐dimensional network. The KTA3? anion adopts an uncommon twist conformation in (CH3)4N+] ? 2 C(NH2)3+] ? KTA3?] ? 2 H2O ( 3 ). The crystal structure of (nC3H7)4N+] ? 2 C(NH2)3+] ? KTA3?] ( 4 ) features a tetrahedral aggregate of four guanidinium ions stabilized by an outer shell that comprises six equatorial carboxylate groups that belong to separate KTA3?] anions. In 3 (C2H5)4N+] ? 20 C(NH2)3+] ? 11 HKTA2?] ? H2KTA?] ? 17 H2O ( 5 ), an even larger centrosymmetric inner core composed of eight guanidinium ions and six bridging water molecules is enclosed by a crust composed of eighteen axial carboxyl/carboxylate groups from six HKTA2? anions. |
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| Keywords: | crystal engineering guanidinium hydrogen bonds Kemp’ s triacid supramolecular chemistry |
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