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Molecular self‐assembly of dendrimers, non‐covalent polymers and polypseudorotaxanes
Author(s) -
Gibson Harry W.,
Hamilton Lesley,
Yamaguchi Nori
Publication year - 2000
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/1099-1581(200008/12)11:8/12<791::aid-pat29>3.0.co;2-h
Subject(s) - rotaxane , dendrimer , moiety , polymer chemistry , covalent bond , crown ether , self assembly , materials science , polymer , chemistry , supramolecular chemistry , stereochemistry , crystallography , nanotechnology , ion , organic chemistry , crystal structure
Abstract The formation of pseudorotaxanes from dibenzo‐24‐crown‐8 (DB24C8) and secondary aliphatic ammonium ions was reported by Stoddart et al. Based on that molecular recognition motif several systems have been examined as prototypical examples of (1) self‐assembly of dendrimers via pseudorotaxane formation, (2) self‐assembly of linear non‐covalent polymers of the pseudo‐ rotaxane type and (3) control of properties of a polymer by pseudorotaxane formation. Attachment of a DB24C8 moiety to the “focal point” of first, second and third generation benzyl ether dendrons (Fréchet type) allowed solution phase self‐assembly with a core unit consisting of 1,3,5‐tris[p‐( N ‐benzylammoniomethyl)phenyl]benzene to produce the corresponding dendritic pseudoro‐rotaxane structures, which are of nanometer scale. Ditopic hosts were prepared by coupling DB24C8 units with difunctional linear species; ditopic guests were similarly constructed by linking two dibenzylammonium ion moieties. At high concentrations in relatively non‐polar solvents these complementary building blocks self‐assembled into non‐covalently bonded (pseudorotaxane) linear arrays, with high viscosity and fiber forming ability. Treatment of polymethacrylates bearing pendant DB24C8 units with dibenzylammonium $PF_{6}^{-}$ resulted in changes in properties as a result of formation of side‐chain pseudorotaxane units. Copyright © 2000 John Wiley & Sons, Ltd.