Hydrogen-bonding-mediated dynamic covalent synthesis of macrocycles and capsules: new receptors for aliphatic ammonium ions and the formation of pseudo[3]rotaxanes.
This paper describes a novel, highly efficient approach to the self-assembly of monomacrocycles and two-layered capsules by using dynamic covalent chemistry. Intramolecular hydrogen-bonding was used to preorganize aromatic amide-based monomers that contain aldehyde and tert-butoxycarbonylamino units. As a result, in the presence of an excess of trifluoroacetic acid (TFA), four monomers could self-couple to produce macrocycles selectively through the formation of three imine or hydrazone bonds. Three dipodal precursors were also prepared by connecting two hydrogen-bonded segments with a flexible linker. In the presence of TFA, these precursors could also self-couple, leading to the exclusive formation of two-layered capsules. As a result of intramolecular hydrogen-bonding, all the macrocycles and capsules were stable in solution and could be purified by simple recrystallization. The new capsules were able to form complexes with linear propylenediammonium derivatives to give unique two-layered pseudo[3]rotaxanes.
Xu
Xiao-Na
XN
State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Wang
Lu
L
Wang
Gui-Tao
GT
Lin
Jian-Bin
JB
Li
Guang-Yu
GY
Jiang
Xi-Kui
XK
Li
Zhan-Ting
ZT
D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry
D000644:Quaternary Ammonium Compounds; D043862:Rotaxanes