Molecular signal transduction by conformational transmission: Use of tetrasubstituted perhydroanthracenes as transducers

2,3,6,7-Tetrasubstituted cis-anti-cis perhydroanthracenes have been studied as conformational transducers for molecular signal transduction. 2,2'-Bipy ridine groups attached to the perhydroanthracene through ether linkages wer e chosen as receptor substituents, while pyrene groups were selected as eff ecters. A chelation-induced triple ring flip of the perhydroanthracene coul d be achieved by the complexation of zinc(II) ions at the bipyridine sites of ligands 13 and 15. It was found that two pyrene substituents attached to the perhydroanthracene via a linker with an E double bond and an ester gro up could be used to monitor the triple ring flip. In the equatorial positio ns, the pyrenes are sufficiently close to form an excimer in the excited st ate, giving a fluorescence signal at 480 nm. In the axial positions, they a re far away from each other and give mainly a monomer fluorescence signal a t 380 nm. Both the bipyridine receptor and the pyrene effector are present in compound 33. The conformational switching 34-->35 (the two conformers of 33) has successfully been used fur a signal transduction over a signal dis tance of 2 nm.