A water-soluble, photoresponsive macrocycle (1), composed of two N + cations and two azobenzene units, has been synthesized. This cyclophane changes its cavity shape in response to a photoinduced trans-cis isomerization of the azobenzene moieties. The photoresponsive association behaviour has been examined for mono- and di-carboxylate guest molecules through spectral studies, thermal cis→trans isomerization, and electrical conductance measurements. It has been shown that cis-(1) strongly binds guest molecules having a general structure -OOC(CH2) nCOO-, the driving force for the guest binding being the electrostatic force between two N+ cations and two carboxylate anions and the hydrophobic force between the cis-azobenzene units and a -(CH 2)n-chain. The results establish that the guest selectivity in host-guest chemistry can be controlled by the enforced change in the cavity shape.
|Number of pages||5|
|Journal||Journal of the Chemical Society, Perkin Transactions 2|
|Publication status||Published - Dec 1 1990|
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