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Controlled Stacking and Unstacking of Peripheral Chlorophyll Units Drives the Spring‐Like Contraction and Expansion of a Semi‐Artificial Helical Polymer
Author(s) -
Numata Munenori,
Kinoshita Daiki,
Hirose Naoya,
Kozawa Tomohiro,
Tamiaki Hitoshi,
Kikkawa Yoshihiro,
Kanesato Masatoshi
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203569
Subject(s) - stacking , contraction (grammar) , spring (device) , polymer , materials science , smart polymer , physics , composite material , biology , thermodynamics , nuclear magnetic resonance , endocrinology
Developing new strategies for controlling polymer conformations through precise molecular recognition can potentially generate a machine‐like motion that is dependent on molecular information—an important process for the preparation of new intelligent nanomaterials (e.g., polymer‐based nanomachines) in the field bordering between polymer chemistry and conventional supramolecular sciences. Herein, we propose a strategy to endow a helical polymer chain with dynamic spring‐like (contraction/expansion) motion through the one‐dimensional self‐assembly (aggregation/disaggregation) of peripheral amphiphilic molecules. In this developing system, we employed a semi‐artificial helical polysaccharide presenting peripheral amphiphilic chlorophyll units as a power device that undergoes contractive motion in aqueous media, driven by strong π–π interactions of its chlorophyll units or by cooperative molecular recognition of bipyridyl‐type ligands through pairs of chlorophyll units, thereby converting molecular information into the regulated motion of a spring. In addition, this system also undergoes expansive motion through coordination of pyridine. We anticipate that this strategy will be applicable (when combined with the established wrapping chemistry of the helical polysaccharide) to the development of, for example, drug carriers (e.g., nano‐syringes), actuators (stimuli‐responsive films), and directional transporters (nano‐railways), thereby extending the frontiers of supramolecular science.