pH‐Controlled Molecular Switches and the Substrate‐Directed Self‐Assembly of Molecular Capsules with a Calix[4]pyrrole Derivative |
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| Authors: | Grazia Cafeo Dr Franz?H Kohnke Prof Luca Valenti Andrew?J?P White Dr |
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| Institution: | 1. Dipartimento di Chimica Organica e Biologica, Università di Messina, Salita Sperone 31, 98166 Messina (Italy), Fax: (+39)?09039‐3895;2. Chemical Crystallography Laboratory, Department of Chemistry, Imperial College London, South Kensington, London, SW7?2AZ (UK) |
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| Abstract: | 10α,20α‐Bis(4‐nitrophenyl)calix4]pyrrole ( 1 ) forms 1:1 complexes with anions of selected aromatic hydroxy acids in which the host orientation within the guest is controlled by a change in the pH value. Some bis‐anionic guests, including those obtained from 4‐hydroxybenzoic acid, 1,4‐ and 1,3‐benzenedicarboxylic acids, induce the self‐assembly of molecular capsules involving two molecules of the receptor. 1H NMR data and solid‐state structures of the 1:1 complex of 1 with p‐C6H4(COOH)(COO?)+NMe4 and the 2:1 capsule ( 1 )2m‐C6H4(COO?)2(+NMe4)2] provide structural details in solution and in the solid state. |
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| Keywords: | anions calixpyrroles capsules hydrogen bonding molecular recognition self‐assembly |
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