Construction, DNA wrapping and cleavage of a carbon nanotube–polypseudorotaxane conjugate

Chem. Commun.,2009, 4106-4108.
Abstract:A supramolecular assembly of carbon nanotubes was constructed by non-covalently wrapping cyclodextrin-based polypseudorotaxanes on single wall carbon nanotubes; the assembly showed good abilities in wrapping and cleaving double-stranded DNA.
Supramolecular Assembly of Perylene Bisimide with b-Cyclodextrin Grafts as a Solid-State Fluorescence Sensor for Vapor Detection
Adv. Funct. Mater.,2009, 19(14), 2230-2235.
Abstract:A nanoscopic supramolecular aggregate is constructed from perylene bisimide-bridged bis-(permethyl-b-cyclodextrins) 1 via p–p stacking interactions. Its self-assembly behavior in organic and aqueous solutions is investigated by UV–Vis, fluorescence, and 1H NMR spectroscopy. Transmission electron microscopy and scanning electron microscopy images show the 1D nanorod aggregation of 1, which is birefringent under crossed polarizer conditions and strongly fluorescent as depicted in the fluorescence microscopy image. X-ray powder diffraction measurements indicate that 1 forms a well-ordered crystalline arrangement with a p–p stacking distance of 4.02A°. Furthermore, the solid-state fluorescence sensing is explored by utilizing the poly(vinylidene fluoride) membrane-embedded 1, giving that 1, as a novel vapor detecting material, can probe several kinds of volatile organic compounds and, especially, exhibits high sensitivity to organic amines.
A Reversible Luminescent Lanthanide Switch Based on a Dibenzo[24]-Crown-8-Dipicolinic Acid Conjugate
Org. Lett., 2008, 10(24), 5557-5560.
Abstract:A novel host molecule H21 bearing a dibenzo[24]-crown-8 moiety and a dipicolinic acid group was synthesized, and its Tb3+ complex displayed a satisfactory luminescent emission. The tris[2]pseudorotaxane formed from [Tb·13]3- and ferrocene derivative 2 reveals excellent reversible luminescent lanthanide behavior.
Polymeric Pseudorotaxane Constructed from Cucurbituril and Aniline and Its Radical Cation Stabilization
Angew. Chem. Int. Edit., 2008, 47(38), 7293-7296.
Abstract:A PANI/cucurbituril polypseudorotaxane was successfully constructed with a regular one-dimensional linear structure in satisfactory yield. Spectrophotometric and electrochemical studies demonstrated that the introduction of
many cucurbituril macrocycles onto a long PANI chain effectively stabilizes the radical cation form, that is, the conductive doped form, of PANI through complexation of the cucurbituril macrocycles with the cationic units of PANI.
Supramolecular Architectures of b-Cyclodextrin-Modified Chitosan and Pyrene Derivatives Mediated by Carbon Nanotubes and their DNA Condensation
J. Am. Chem. Soc., 2008, 130(31), 10431-10439.
Abstract:β-Cyclodextrin-modified chitosan 1 was synthesized via the Schiff base reaction between 6-O- (4-formylphenyl)-β-cyclodextrin and chitosan (CHIT), and then the supramolecular dyad assemblies 2 and 3 were respectively fabricated from the subunit 1 through the inclusion of adamantane-modified pyrene into the β-cyclodextrin cavity and the wrapping of a CHIT chain on multiwalled carbon nanotubes (MWCNTs). The water-soluble dyad 3 further interacted with adamantane-modified pyrene, forming a stable triad assembly 4. They were extensively characterized by NMR, thermogravimetric analysis, UV-vis, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy (AFM). Furthermore, the DNA condensation abilities of 1-4 were validated by AFM and dynamic light scattering, which indicates that the DNA-condensing capability of CHIT can be pronouncedly improved by either the pyrene grafts or the MWCNT medium. The cooperation between cationic and aromatic groups as well as the dispersion of CHIT agglomerates by MWCNTs are the key factors to enhance DNA condensation of cationic polymers.
Construction of a Long Cyclodextrin-Based Bis(molecular tube) from Bis(polypseudorotaxane) and Its Capture of C60
ACS Nano, 2008, 2(3), 554-560.
Abstract:The preorganized bis(polypseudorotaxane) (about 20 nm long) formed by the multiple metallobridged poly(β-cyclodextrin)s has been successfully converted to the lengthened bis(molecular tube) (about 200 nm long) through the intermolecular joining of about 10 discrete bis(polypseudorotaxane) units and the subsequent removal of the polymer templates. The obtained bis(molecular tube), which is quite soluble in water, dimethylformamide, and dimethyl sulfoxide, has been comprehensively characterized by NMR, gel permeation chromatography, static light scattering, X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and scanning tunneling microscopy. Further investigations demonstrate that this bis(molecular tube) can capture C60 through interaction with its manyπ-electron-rich biquinolino groups.
Complexation-Induced Transition of Nanorod to Network Aggregates: Alternate Porphyrin and Cyclodextrin Arrays
J. Am. Chem. Soc., 2008, 130(2), 600-605.
Abstract:Tetrakis(permethyl-β-cyclodextrin)-modified zinc(II) porphyrin (1) and tetra(β-cyclodextrin)-modified zinc(II) porphyrin (2) were synthesized via “click chemistry”. Intermolecular inclusion complexation of these structurally similar 1 and 2 with tetrasodium tetraphenylporphyrintetrasulfonate (3) led to formation of two distinctly different nanoarchitectures with alternate porphyrin and cyclodextrin arrays, which were proven to be network and nanorod aggregates, respectively, by using transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. From the results of comparative studies in different solutions, we elucidated the mechanisms that result in nanorod to network aggregates transition, concluding that the complexation strength of porphyrin with cyclodextrin is a crucial factor to activate the potential
binding sites of a molecular building block.

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