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Indexed by:期刊论文

Date of Publication:2011-05-02

Journal:CHEMISTRY-AN ASIAN JOURNAL

Included Journals:SCIE

Volume:6

Issue:5

Page Number:1225-1233

ISSN No.:1861-4728

Key Words:glutathione; host-guest systems; metal-organic frameworks; sensors; supramolecular chemistry

Abstract:Two trinuclear zinc- based cyclohelicates, Zn-PDB (PDB=[5-(di-benzylamino)-N1',N3'-bis(pyridin-2-yl-methylene)isophthalohydrazide]) and Zn-PMB (PMB=[5-(bodipy-oxy)-N1',N3'- bis(pyridin-2-ylmethylene)isophthalohydrazide]) containing dibenzylamino and BODIPY groups, respectively, were generated by incorporating two amide-containing tridentate chelators into meta-positions of a substituted phenyl ring. Single-crystal structure analysis and related spectroscopic characterizations demonstrated the formation of macrocyclic helicals both in the solid state and in solution. The host-guest behavior of the cyclohelical hosts towards gamma-glutamyl-cysteinyl-glycine (GSH) and its component amino acids was investigated by spectroscopic titrations. UV/Vis absorption titration and NMR titrations of Zn-PDB and Zn-PMB upon addition of the above-mentioned guests suggested that the Glu residue of GSH was positioned within the cavity. The COO(-) groups interacted with metal ions through static interactions. The Cys moiety of GSH interacted with the amide groups sited in host molecules through hydrogen-bonding interactions to produce measurable spectral changes. Fluorescent titrations of Zn-PMB upon the addition of GSH and ESI-MS investigations of the titration solutions confirmed the host-guest interaction modes and revealed the possible 1:1 complexation stoichiometry. These results showed that the recognition of a substrate within the cavity of functionalized metal-organic cage-like receptors could be a useful method to produce supramolecular sensors for biomolecules.