ABSTRACT: Interactions between a symmetrical tetramethyl-substituted cucurbituril (host: TMeQ) and 1,ω-alkylenedipyridine (ω =
2, 4, 6, 8, 10) dicationic guests were investigated using 1H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes, combined cavity and portal binding
in TMeQ were observed, and the length of the bridged alkylene was found to play an important role not only in balancing
the overall hydrophilic/hydrophobic interaction between the host and the guest, but also in defining the structure of the
resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy), TMeQ includes a positively charged pyridine
ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy), TMeQ includes a positively
charged pyridine ring of Bdpy, but the different competitive interactions in and between the related inclusion complexes could
lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains, such as 1,6-hexamethylenedipyridine
(Hdpy) or 1,8-octylenedipyridine (Odpy), a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic
cavity and the outer portal dipole-ion interactions. However, for 1,10-decatylenedipyridine (Ddpy), the two TMeQ host molecules
include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex.
Science in China Series B Chemistry 04/2012; 52(4):475-482. · 1.20 Impact Factor
ABSTRACT: A new tripodal rhodamine B derivative 2 was designed and synthesized by tripodal trialdehyde and rhodamine B hydrazide for
the first time. This derivative could be used as a fluorescent chemosensor for the selective and sensitive determination of
copper(II) in Tris-HCl buffer and ethanol aqueous mixed media. Under the optimum conditions described herein, fluorescence
enhancement at 557/577 nm was linearly related to the concentration of copper(II) in the range of 0.10 to 10.00×10−5 mol·L−1, with a correlation coefficient of R
2=0.9964 (n=15) and a detection limit of 1.129×10−7 mol·L−1 (the relative standard deviation for five repeated measurements at 4.00×10−5 mol·L−1 Cu(II) was 2.2%). The absorbance measurements at 557 nm were linearly related to the concentration of Cu(II) in the range
of 0.50 to 25.00×10−5 mol·L−1, with a correlation coefficient of R
2=0.9948 (n=13) and a detection limit of 3.338×10−7mol·L−1.
Science in China Series B Chemistry 04/2012; 52(4):523-528. · 1.20 Impact Factor
ABSTRACT: The novel fluorescent sensor 1, which is comprised of two rhodamine B lactams as fluorophores that are 1,3-alternately linked to a thiacalixarene, behaves
as a highly sensitive ion-induced fluorescent sensor for Fe3+ and Cr3+. This compound was synthesized, and its recognition of metal ions was evaluated by fluorescence and absorption spectroscopy.
The possible mechanism of Fe3+- and Cr3+-induced spirocycle opening of 1 leads to fluorescent and colorimetric enhancement, and these properties were investigated by spectroscopy, 1H NMR and IR. The stoichiometric ratios and association constants of the complexes between 1 and these ions have been measured and calculated, and showed that the presence of Fe3+ or Cr3+ induced sensor 1 to form a stable 1:1 complex.
Journal of Inclusion Phenomena 04/2012; 68(1):139-146. · 1.89 Impact Factor
ABSTRACT: Cucurbit[n]urils (Q[n]) are promising ligands for the coordination of metal ions, metal complexes or clusters, and form various Q[n]-based complexes. Among the Q[n] complexes, those formed by direct coordination between Q[n]s and metal ions are particularly important. The direct coordination of metal ions to cucurbit[n]urils leads to the formation of Q[n]-based molecular capsules, tubular polymers and molecular bracelets, which could have nanoscale applications in drug delivery,
molecular devices and new materials.
Keywordsmetal ions-cucurbit[n]urils-direct coordination-molecular capsules-tubular polymers-molecular bracelets
Chinese Science Bulletin 04/2012; 55(32):3633-3640. · 1.32 Impact Factor
ABSTRACT: Synthesis of a symmetrical tetrasubstituted cucurbituril has been achieved by using the diether of dimethylglycoluril (1)
and the dimmer of glycoluril (2). The structure of the symmetrical tetramethylcucurbituril (TMeQ) has been determined
by single crystal X-ray diffraction, 1H NMR spectroscopy and ESMS. The 1H NMR spectra of 2,2′-bipyridine added to TMeQ reveal that the host-guest inclusion complex was easily formed.
Chinese Science Bulletin 04/2012; 49(11):1111-1116. · 1.32 Impact Factor
ABSTRACT: The host-guest relationship between cucurbituril, phenanthrolines and some methyl substituted 1,10-phenanthrolines has
been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy. The results showed that phenanthrolines as molecular guests bind in the
cavity and portal of cucurbituril in a ratio of 2:1 (guest to host). The phenanthroline isomers 1,10-,1,7- and 4,7- showed
red shifts between 47 and 108 nm and pronounced increases in fluorescent intensity. These same isomers produced inclusion
complexes with cucur-bituril which had moderate to fast exchange rates on the 1H NMR time scale. The methyl substituted 1,10-phenanthrolines studied gave stable inclusion complexes in a ratio of 2:1 which
showed slow exchange rates. These guests formed п-п stacked pairs which were cavity bound but also partly protruded from only
one portal forming unsymmetrical host-guest complexes. In addition, these п-п stacked pairs formed orientation isomers within
the confines of the cucur-bituril cavity.
Science in China Series B Chemistry 06/2005; 48(4):305-314. · 1.20 Impact Factor
ABSTRACT: Three guests with two moiety probes for different Cucurbit[n = 6-8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)-adamataneamine
and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q and adamataneamine typically
for Q. The host-guest complexes of Cucurbit[n = 6-8]urils with these guests have been investigated by using NMR techniques
and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-guest
Science in China Series B Chemistry 01/2004; 47(4):301-310. · 1.20 Impact Factor
ABSTRACT: Self-assembled complexes between cage compounds cucurbit[n = 5–8]urils and hexamethylenetetramine were studied by using NMR
techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit  uril to forming self-assembled capsules
in which nothing is encapsulated yet; the cavity of the cucurbituril can accommodate a hexamethylenetetramine molecule
to form a selfassembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbituril with hexamethylenetetramine·HCl
and the portal interaction of the dipole carbonyl of the cucurbituril with hexamethylenetetramine·HCl lead to form self-assembled
capsules in which the hexamethylenetetramine·HCl are encapsulated in the hexamethylenetetramine·HCl “lidded” cucurbituril.
Although the structures of the portal and cavity to cucurbituril are similar, there is no obvious interaction between decamethylcucurbituril
and hexamethylenetetramine, and also between cucurbit uril or cucurbituril and hexamethylenetetramine.
Chinese Science Bulletin 11/2003; 48(24):2694-2697. · 1.32 Impact Factor
ABSTRACT: Two partially methyl substituted cucurbituril, PMeQ and HMeQ, were synthesized from 3a-methyl-glycoluril. They were characterized by 1H NMR, ES-MS and single crystal X-ray diffraction. Ab initio calculations showed that each isolated methyl substituted cucurbit[n]uril is the most stable form among its all possbile isomers. One of the remarkable properties of these two partially substituted cucurbituril is their high solubility in the commonly used solvents such as water, methanol, and DMSO.
Journal of Molecular Structure. 875:442-446.