Synthesis and Study of New β‐Cyclodextrin ‘Dimers’ Having a Metal Coordination Center and carboxamide or urea linkers

Abstract

Abstract The synthesis of new ‘bridged’ β‐cyclodextrin (β‐CD) ‘dimers’ 7–12 was successfully achieved by two one‐pot reactions from β‐CD (3) and 6 A ‐azido‐6 A ‐deoxy‐β‐CD (4) . The ‘phosphine imine’ reaction was shown to be a superior approach compared to the Mitsunobu reaction as coupling strategy for the preparation of these ‘dimers’. NMR Data, along with molecular‐modelling calculations, suggest a ‘helical‐like’ arrangement for the phenanthroline‐diyl‐linked ‘dimer’ derivative 9 . Complexation properties of 9 were established by UV‐VIS‐spectrophotometric titration toward four metals. Among them Cu II or Eu III ions were complexed selectively by 9 , but no complexation occurred with La III and Zn II . In addition a specific and interesting esterase activity toward the phosphodiester bond of bis(4‐nitrophenyl) phosphate anion was found in the case of the Cu II complex of 9 .