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Five‐State Molecular Shuttling of a Pair of [2]Rotaxanes: Distinct Outputs in Response to Acid and Base Stimuli
Author(s) -
Ueda Masahiro,
Terazawa Shoya,
Deguchi Yasuaki,
Kimura Masaki,
Matsubara Naoki,
Miyagawa Shinobu,
Kawasaki Tsuneomi,
Tokunaga Yuji
Publication year - 2016
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201600743
Subject(s) - rotaxane , protonation , chromophore , crown ether , chemistry , free base , base (topology) , absorption (acoustics) , stereochemistry , ammonium , photochemistry , molecule , polymer chemistry , materials science , supramolecular chemistry , organic chemistry , ion , mathematical analysis , salt (chemistry) , mathematics , composite material
Abstract In this study we synthesized two acid‐/base‐controllable [2]rotaxanes featuring aminodiazobenzene and aminocoumarin units, respectively, as chromophores and dibenzo[24]crown‐8 and dibenzo[25]crown‐8 units, respectively, as their macrocyclic components. Each [2]rotaxane contained N ‐alkylarylamine (ammonium) and N , N ‐dialkylamine (ammonium) centers as binding sites for their crown ether components. The absorption patterns of the chromophores were dependent on the position of the encircling macrocyclic component and the degree of protonation, with three distinct states (under acidic, neutral, and basic conditions) evident for each [2]rotaxane. The mixed [2]rotaxane system displayed stepwise and independent molecular shuttling behavior based on the degree of protonation of the amino groups in response to both the amount and strength of added acids or bases; as such, the system provided five different absorption signals as outputs that could be read using UV/Vis spectroscopy.