Strong stacking between FH--N hydrogen-bonded foldamers and fullerenes: formation of supramolecular nano networks.
The stacking interactions between FH--N hydrogen-bonded foldamers 1-3, bis-foldamer 4, and tris-foldamer 5 and C(60) and C(70) are described. Compound 4 contains two folded units, which are connected by an isophthalamide linker, whereas 5 has a C(3)-symmetrical discotic structure, in which three folded units are connected by a benzene-1,3,5-tricarboxamide unit. UV/Vis, fluorescence, and NMR experiments have revealed that the foldamers or folded units strongly stack with fullerenes in chloroform. The (apparent) association constants of the respective complexes have been determined by a fluorescence titration method. The strong association is tentatively attributed to intermolecular cooperative fluorophenylpi and solvophobic interactions. A similar but weaker interaction has also been observed between an MeOH--N hydrogen-bonded foldamer and fullerenes. AFM studies have revealed that the surfaces of 3 and 4 show fibrous networks, while the surface of 5 shows particles. In sharp contrast, mixtures of 3 and 4 with C(60) have been shown to generate thinner separated fibrils, whereas a mixture of 5 and C(60) produces honeycomb-like nano networks, for which a columnar cooperative stacking pattern is proposed. The results demonstrate the usefulness of FH--N hydrogen-bonded folded structures in the construction of nanoscaled materials.
Li
Chuang
C
State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai, China.
Zhu
Yuan-Yuan
YY
Yi
Hui-Ping
HP
Li
Chang-Zhi
CZ
Jiang
Xi-Kui
XK
Li
Zhan-Ting
ZT
Yu
Yi-Hua
YH
D037741:Fullerenes / Q000737:chemistry*; D006858:Hydrofluoric Acid / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009584:Nitrogen / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D017186:Titrimetry
D037741:Fullerenes; D009584:Nitrogen; D006858:Hydrofluoric Acid