TY - JOUR
T1 - Supramolecular polymers in aqueous medium
T2 - Rational design based on directional hydrophobic interactions
AU - Ustinov, Alona
AU - Weissman, Haim
AU - Shirman, Elijah
AU - Pinkas, Iddo
AU - Zuo, Xiaobing
AU - Rybtchinski, Boris
PY - 2011/10/12
Y1 - 2011/10/12
N2 - Self-assembly in aqueous medium is of primary importance and widely employs hydrophobic interactions. Yet, unlike directional hydrogen bonds, hydrophobic interactions lack directionality, making difficult rational self-assembly design. Directional hydrophobic motif would significantly enhance rational design in aqueous self-assembly, yet general approaches to such interactions are currently lacking. Here, we show that pairwise directional hydrophobic/π- stacking interactions can be designed using well-defined sterics and supramolecular multivalency. Our system utilizes a hexasubstituted benzene scaffold decorated with 3 (compound 1) or 6 (compound 2) amphiphilc perylene diimides. It imposes a pairwise self-assembly mode, leading to well-defined supramolecular polymers in aqueous medium. the assemblies were characterized using cryogenic electron microscopy, small-angle X-ray scattering, optical spectroscopy, and EPR. Supramolecular polymerization studies in the case of 2 revealed association constants in 10 8 M -1 range, and significant enthalpic contribution to the polymerization free energy. The pairwise PDI motif enables exciton confinement and localized emission in the polymers based on 1 and 2's unique photonic behavior, untypical of the extended π-stacked systems. Directional pairwise hydrophobic interactions introduce a novel strategy for rational design of noncovalent assemblies in aqueous medium, and bring about a unique photofunction.
AB - Self-assembly in aqueous medium is of primary importance and widely employs hydrophobic interactions. Yet, unlike directional hydrogen bonds, hydrophobic interactions lack directionality, making difficult rational self-assembly design. Directional hydrophobic motif would significantly enhance rational design in aqueous self-assembly, yet general approaches to such interactions are currently lacking. Here, we show that pairwise directional hydrophobic/π- stacking interactions can be designed using well-defined sterics and supramolecular multivalency. Our system utilizes a hexasubstituted benzene scaffold decorated with 3 (compound 1) or 6 (compound 2) amphiphilc perylene diimides. It imposes a pairwise self-assembly mode, leading to well-defined supramolecular polymers in aqueous medium. the assemblies were characterized using cryogenic electron microscopy, small-angle X-ray scattering, optical spectroscopy, and EPR. Supramolecular polymerization studies in the case of 2 revealed association constants in 10 8 M -1 range, and significant enthalpic contribution to the polymerization free energy. The pairwise PDI motif enables exciton confinement and localized emission in the polymers based on 1 and 2's unique photonic behavior, untypical of the extended π-stacked systems. Directional pairwise hydrophobic interactions introduce a novel strategy for rational design of noncovalent assemblies in aqueous medium, and bring about a unique photofunction.
UR - http://www.scopus.com/inward/record.url?scp=80053535138&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80053535138&partnerID=8YFLogxK
U2 - 10.1021/ja2066225
DO - 10.1021/ja2066225
M3 - Article
C2 - 21882828
AN - SCOPUS:80053535138
VL - 133
SP - 16201
EP - 16211
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 40
ER -