A biconformational perhydroanthracene 1 was used as a signal transducer. Upon binding of a zinc(II) ion at the bipyridine receptor site, a fluorescence signal is generated at the pyrene effector site.

Keywords: Biconformational double ring flip / Conformation analysis / Decalin / Signal transduction / Synthesis design 2,3,6,7-Tetrasubstituted decalins of relative configuration (2β,3α,4aα,6α,7β,8aα) have been synthesized. If substituents as in 6 are chosen, the equilibrium of the biconformational system 2/3 is shifted towards conformer 2. Conversion into the bis(acetal) 16 resulted in a covalently induced double ring flip 17 Ǟ 18. A chelation-induced double ring flip (21 Ǟ 22) was achieved when 2,2Ј-bipyridyl substituents were attached by ether linkages at the receptor positions 6 and 7 of the decalin system. Effector groups were introduced by

2,3,6,7-Tetrasubstituted cis-anti-cis perhydroanthracenes have been studied as conformational transducers for molecular signal transduction. 2,2'-Bipyridine groups attached to the perhydroanthracene through ether linkages were chosen as receptor substituents, while pyrene groups were selected as effectors. A chelation-induced triple ring flip of the perhydroanthracene could 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 group could be used to monitor the triple ring flip. In the equatorial positions, the pyrenes are sufficiently close to form an excimer in the excited state, giving a fluorescence signal at 480 nm. In the axial positions, they are far away from each other and give mainly a monomer fluorescence signal at 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 for a signal transduction over a signal distance of 2 nm.

2,3,6,7‐Tetrasubstituted perhydroanthracenes with the relative configuration 2β,3α,4aα,6β,7α,8aβ,9aα,10aβ have been synthesized stereoselectively. The biconformationality of these compounds has been investigated in solution by NMR and in the solid state by X‐ray crystallography. A triple‐ring flip 2 → 3 was realized for the first time by the covalently induced transition 29 → 30.

2,3,6,7‐Tetrasubstituted perhydroanthracenes with the relative configuration 2β,3α,4aα,6β,7α,8aβ,9aα,10aβ have been synthesized stereoselectively. The biconformationality of these compounds has been investigated in solution by NMR and in the solid state by X‐ray crystallography. A triple‐ring flip 2 → 3 was realized for the first time by the covalently induced transition 29 → 30.