Heteroditopic rhenium(I) and ruthenium(II0 bipyridyl calix[4]arene receptors for binding cation-anion ion pairs

摘要

New heteroditpopic ion pair receptors that contain rhenium(I0 and ruthenium(II0 bipyridyl amide anion recognition sites covalently linkedto a lower rim calix[4]arene tetraester alkali metal cation binding site have been prepared and shown to bind alkali metal (Li~+, Na~+)-halide (Be~-, I~-), ion pair species. Proton NMR titration studies reveal the lower rim ester co-bound alkali metal cation significantly enhances the strength of bromide and iodide binding n acetonitrile solutions with the largest positive co-operative binding effect of sixtyfold observed with bromide and the lithium complex of one receptor. Solid/liquid extraction experiments show two of the receptors are capable of solutilising NaCl and NaOAc in dichloromethane solutions.