TehlhedronLotteas. Vol.31.No.27.PP 39193922.1990 Printed in Gmu Britain clo4mo39/90 $3.00 + Ml PergammPress pbz A NOVEL TYPE OF PSEUDOCRYPTAND FOR SIMULTANEOUS RECOGNITION OF HEAVY AND ALKALI METALS Tatsuya Nabeshima, a* Tadashi Inaba,b Takahiio Sagae,b and Naomichi Furukawab* a) Department of Chemistry, Gunma University, Kiryu, Gunma 376, Japan, b) Department of Chemistry, University of Tsukuba, Tsukuba, Ibaraki 305, Japan Abstract: Simultaneous and stable recognition for two different metals, e.g. Cu+ and K+, has been achieved by using diazacrown ether with 2,2-bipyridine moieties. Formation of pseudocrown structure of the Cu+ complexes provides a suitable recognition cavity for alkali metal ion. In biological systems allosterism and cooperativity of enzymes are due to the conformational change of the apoproteins,l) which should be also very useful to construct an artificial switching system for a molecular function. Recently we have reported synthesis and binding properties to alkali metal ions of an artificial ionophore 6-0-bpy with two kinds of recognition sites for metal ionsP) On the addition of Cu+, 6-0-bpy is immediately converted to the tetrahedral complex, accompanying conformational change of the polyether Meow;O;gMe 6-0-bpy chain to cyclic (pseudocrown) structure, which can dramatically enhance the selectivity on transport of alkali metal ion across liquid membrane.23) In other words selective and simultaneous recognition of two different metals, which is one of the most important and Scheme 1 M*+ : Transition Metal Pseudocryptand 3919