Amino acid ester salt recognition by ferrocene-based ditopic receptor bearing oligoethylene glycol with pendant bipy subunits: CV, UV-vis and ESR studies
Takashi Murashima,Sayo Tsukiyama,Satoshi Fujii,Kazuyuki Hayata,Hiroshi Sakai,Toshifumi Miyazawa,Takashi Yamada
Organic & Biomolecular Chemistry Pub Date : 10/05/2005 00:00:00 , DOI:10.1039/B511233H
Abstract

The novel ferrocene-based ditopic receptor 1 was synthesized. This receptor bears two oligoethylene glycol arms with pendant 2,2′-bipyridine unit at the identical cyclopentadienyl rings, CuI cation binds to 1 to form the 1 : 1 complex (1·CuI) with the cavity consisting of polyether, and the resulting complex acts as a receptor for amino acid ester salts to give the ditopic complex (1·CuI·AAOMe–HCl). The 1H NMR spectrum of 1·CuI·LeuOMe–HCl exhibits strong broadening at the bipyridine region, and the ESR spectrum of the same sample gives the signals assigned as CuII species. With these data, the binding of 1·CuI towards AAOMe·HCl leads to the conformational change, and the CuI complex is simultaneously oxidized to the CuII complex.

Graphical abstract: Amino acid ester salt recognition by ferrocene-based ditopic receptor bearing oligoethylene glycol with pendant bipy subunits: CV, UV-vis and ESR studies