TY - JOUR
T1 - Synthesis and Thermal Responses of Polygonal Poly(ethylene glycol) Analogues
AU - Kawasaki, Shunichi
AU - Muraoka, Takahiro
AU - Hamada, Tsutomu
AU - Shigyou, Kazuki
AU - Nagatsugi, Fumi
AU - Kinbara, Kazushi
N1 - Funding Information:
We are grateful to Ms. Akiko Nakade for her technical assistance. This work was partially supported by Grant-in-Aid for Scientific Research on Innovative Areas "Spying Minority in Biological Phenomena (No.3306)" (23115003 to K.K.), the Mitsubishi Foundation (K.K.), Grant-in-Aid for Scientific Research on Innovative Areas "?-System Figuration (No.2601)" (26102001 to T.M.), Grant-in-Aid for Scientific Research C (26410170 to T.M.), JST PRESTO program "Molecular Technology and Creation of New Functions" (T.M.), Grant-in-Aid for Scientific Research on Innovative Areas "Synergy of Fluctuation and Structure (No.2502)" (26103516 to T.H.), Grant-in-Aid for Scientific Research on Innovative Areas "Molecular Robotics (No.2403)" (15H00807 to T.H.), Sunbor Scholarship of the Suntory Foundation for Life Sciences (K.S.), and the Management Expenses Grants for National Universities Corporations from Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Publisher Copyright:
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA.
PY - 2016/4/5
Y1 - 2016/4/5
N2 - As a new type of topological poly(ethylene glycol) (PEG) analogue, a series of polygonal PEGs with digonal to hexagonal structures were developed. Polygonal PEGs with structures between the digonal and tetragonal types showed molecular-level dispersion in water at 20 °C, whereas the pentagonal and hexagonal PEGs aggregated, which is suggestive of enhanced hydrophobicity by ring expansion. Heating induced conformational changes in the polygonal PEGs and increased their hydrophobicity. Among the polygonal PEGs, only the trigonal and hexagonal PEGs showed a distinct thermal response to form and increase the size of the aggregates, respectively. Given that tetragonal and pentagonal PEGs only marginally responded to heat treatment, the thermal responses are likely due to a topological effect. At low temperatures, the larger polygonal PEGs are more restricted despite the expanded rings. The trigonal PEG showed the largest change in mobility, whereas the tetragonal PEG exhibited the smallest change. Hence, the topology of the polygonal PEGs influences the intramolecular packing and the local dynamics.
AB - As a new type of topological poly(ethylene glycol) (PEG) analogue, a series of polygonal PEGs with digonal to hexagonal structures were developed. Polygonal PEGs with structures between the digonal and tetragonal types showed molecular-level dispersion in water at 20 °C, whereas the pentagonal and hexagonal PEGs aggregated, which is suggestive of enhanced hydrophobicity by ring expansion. Heating induced conformational changes in the polygonal PEGs and increased their hydrophobicity. Among the polygonal PEGs, only the trigonal and hexagonal PEGs showed a distinct thermal response to form and increase the size of the aggregates, respectively. Given that tetragonal and pentagonal PEGs only marginally responded to heat treatment, the thermal responses are likely due to a topological effect. At low temperatures, the larger polygonal PEGs are more restricted despite the expanded rings. The trigonal PEG showed the largest change in mobility, whereas the tetragonal PEG exhibited the smallest change. Hence, the topology of the polygonal PEGs influences the intramolecular packing and the local dynamics.
KW - aggregation
KW - conformational changes
KW - macrocycles
KW - poly(ethylene glycol)
KW - topology
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U2 - 10.1002/asia.201501381
DO - 10.1002/asia.201501381
M3 - Article
C2 - 26864823
AN - SCOPUS:84959564399
VL - 11
SP - 1028
EP - 1035
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
SN - 1861-4728
IS - 7
ER -