Kumar, Subodh ; Hundal, Maninder Singh ; Hundal, Geeta ; Singh, Palwinder ; Bhalla, Vandana ; Harjit Singh, (1998) Synthetic ionophores. Part 18: Ag+ selective trithiabenzena-and dithiabenzenapyridinacyclophanes Journal of the Chemical Society, Perkin Transactions 2 (4). pp. 925-932. ISSN 0300-9580
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Official URL: http://pubs.rsc.org/en/Content/ArticleLanding/1998...
Related URL: http://dx.doi.org/10.1039/A706861A
Abstract
The phase transfer catalysed nucleophilic displacement of 1,3-bis(bromomethyl)benzene, 2-methoxy-5- methyl-1,3-bis(bromomethyl)benzene (2) and 1,4-bis(bromomethyl)benzene with 2-mercaptoethanol gives the respective diols 3, 4 and 12 (80-85%), which undergo intermolecular cyclodehydrochlorination with thiodiglycolyl dichloride and pyridine-2,6-dicarbonyl dichloride?HCl to provide m-phenylene (7-10) and p-phenylene (13-14) based crownophanes. The single crystal X-ray structures of crownophanes 8 and 13 and their NMR studies show that the m-phenylene and p-phenylene rings remain in plane and perpendicular to the macrocyclic ring both in solution and solid phases. These crownophanes offer three soft coordinating sites (3 × S or 2 × S and 1 N) conducive to complexation with Ag+ and the steric restrictions imposed by m- and p-phenylene rings restrict 2 :1 (L :M) sandwich complexation required for complexation with the borderline soft Pb2+ cation. The crownophanes 7 and 9 extract Ag+ 172 and 602 times, respectively, more than Pb2+.
Item Type: | Article |
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Source: | Copyright of this article belongs to Royal Chemistry of Society. |
ID Code: | 14744 |
Deposited On: | 12 Nov 2010 13:42 |
Last Modified: | 16 May 2016 23:43 |
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