Chun-Yan Pang

Jiangnan University, Wu-hsi, Jiangsu Sheng, China

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Publications (11)29.97 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Using chiral imidazole Schiff-base as ligands, two couples of mononuclear iron(II) enantiomeric complexes fac-Λ-[Fe(R-L)3](ClO4)2∙ H2O (1), fac-Δ-[Fe(S-L)3](ClO4)2∙ H2O (2), fac-Λ-[Fe(R-L)3](BF4)2∙ H2O (3), fac-Δ-[Fe(S-L)3](BF4)2∙ H2O (4) (L = 1-(2-naphthyl)-N-((1-methyl-imidazol-2-yl)methylene)ethanamine have been successfully synthesized and characterized. The CD spectra of 1 and 2, 3 and 4, were basically mirror images confirming their enantiomers. X-ray crystallography revealed that complexes 1–4 all crystallized in the chiral space group P213 with the iron(II) center surrounded by three bidentate ligands. Magnetic measurements revealed incomplete spin transition for 1, and gradual spin crossover (T1/2 = 150 K) for 3. However, the spin-crossover behaviors were vanished after grafting 1–4 to the merrifield’s peptide resin, and the iron(II) centers in the resin remained high-spin state in the temperature range of 2–300 K.
    No preview · Article · Jan 2015 · Inorganic Chemistry Communications
  • Dong-Hong Ren · Dan Qiu · Chun-Yan Pang · Zaijun Li · Zhi-Guo Gu
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    ABSTRACT: A new class of chiral tetrahedral iron(II) cages was prepared from subcomponent self-assembly with high diastereoselectivity. The cages can be interconvered through imine exchange. The chiral cages displayed spin transition close to room temperature, and the transition temperatures were affected by the substituent and uncoordination solvents.
    No preview · Article · Nov 2014 · Chemical Communications
  • Fei-Fei Bao · Xin-Xin Xu · Wen Zhou · Chun-Yan Pang · Zaijun Li · Zhi-Guo Gu
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    ABSTRACT: DNA condensation induced by a pair of heptameric La(III) helical enantiomers M-[La7(S-L)6(CO3)(NO3)6(OCH3)(CH3OH)7]·2CH3OH·5H2O and P-[La7(R-L)6(CO3)(NO3)6(OCH3)(CH3OH)5(H2O)2]·2CH3OH·4H2O (M-La and P-La, L=2-(2-hydroxybenzylamino)-3-carbamoylpropanoic acid) has been investigated by UV/vis spectroscopy, fluorescence spectroscopy, CD spectroscopy, EMSA, RALS, DLS, and SEM. The enantiomers M-La and P-La could induce CT-DNA condensation at a low concentration as observed in UV/vis spectroscopy. DNA condensates possessed globular nanoparticles with nearly homogeneous sizes in solid state determined by SEM (ca. 250nm for M-La and ca. 200nm for P-La). The enantiomers bound to DNA through electrostatic attraction and hydrogen bond interactions in a major groove, and rapidly condensed free DNA into its compact state. DNA decompaction has been acquired by using EDTA as disassembly agent, and analyzed by UV/vis spectroscopy, CD spectroscopy and EMSA. Moreover, the enantiomers M-La and P-La displayed discernible discrimination in DNA interaction and DNA condensation, as well as DNA decondensation. Our study suggested that lanthanum(III) enantiomers M-La and P-La were efficient DNA packaging agents with potential applications in gene delivery.
    No preview · Article · May 2014 · Journal of Inorganic Biochemistry
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    ABSTRACT: Three new mesoporous silica materials IL15SGs (HF15SG, TF15SG and DF15SG) doped with benzo-15-crown-5 and imidazolium based ionic liquids (C8mim+PF6−, C8mim+BF4− or C8mim+NTf 2−) have been prepared by a simple approach to separating lithium isotopes. The formed mesoporous structures of silica gels have been confirmed by transmission electron microscopy image and N2 gas adsorption–desorption isotherm. Imidazolium ionic liquids acted as templates to prepare mesoporous materials, additives to stabilize extractant within silica gel, and synergetic agents to separate the lithium isotopes. Factors such as lithium salt concentration, initial pH, counter anion of lithium salt, extraction time, and temperature on the lithium isotopes separation were examined. Under optimized conditions, the extraction efficiency of HF15SG, TF15SG and DF15SG were found to be 11.43, 10.59 and 13.07 %, respectively. The heavier isotope 7Li was concentrated in the solution phase while the lighter isotope 6Li was enriched in the gel phase. The solid–liquid extraction maximum single-stage isotopes separation factor of 6Li–7Li in the solid–liquid extraction was up to 1.046 ± 0.002. X-ray crystal structure analysis indicated that the lithium salt was extracted into the solid phase with crown ether forming [(Li0.5)2(B15)2(H2O)]+ complexes. IL15SGs were also easily regenerated by stripping with 20 mmol L−1 HCl and reused in the consecutive removal of lithium ion in five cycles.
    No preview · Article · May 2014 · Journal of Radioanalytical and Nuclear Chemistry
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    ABSTRACT: Three dinuclear nickel triple-stranded supramolecular cylinders [Ni2(L1)3][ClO4]4 (1), [Ni2(L2)3][ClO4]4 (2) and [Ni2(L3)3][ClO4]4 (3) with bis(pyridylimine) Schiff base containing triphenyl groups in the spacers as ligands were synthesized and characterized. The human telomeric G-quadruplexes binding properties of cylinders 1-3 were evaluated by means of UV-Vis spectroscopy, circular dichroism (CD) spectroscopy and fluorescence resonance energy transfer (FRET) melting assay. UV-Vis studies revealed that the supramolecular cylinders 1-3 could bind to G-quadruplex DNA with high binding constants (Kb values ranging from 0.11-2.2×10(6)M(-1)). FRET melting studies indicated that the cylinders 1-3 had much stronger stabilizing effect on G-quadruplex DNA (ΔTm up to 24.5°C) than the traditional cylinder Ni2L3(4+) just containing diphenylmethane spacers (ΔTm=10.6°C). Meanwhile, cylinders 1-3 were found to have a modest degree of selectivity for the quadruplex DNA versus duplex DNA in competition FRET assays. Moreover, CD spectroscopy revealed that complex 1 could induce G-quadruplex formation in the absence of metal ions solution and convert antiparallel G-quadruplex into hybrid structure in Na(+) solution. These results provided a new insight into the development of supramolecular cylinders as potential anticancer drugs targeting G-quadruplex DNA.
    No preview · Article · Jan 2014 · Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy
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    ABSTRACT: A pair of mononuclear iron(II) enantiomeric complexes: fac-Lambda-[Fe(R-L)31(BF4)(2)center dot MeCN (1) and fac-Delta-[Fe(S-L)(3)](BF4)(2)center dot MeCN (2) [L = 1-phenyl-N-(1-methyl-imidazol-2-ylmethylene)ethanamine] have been synthesized and characterized. X-ray crystallography reveals that iron(II) center is surrounded by three bidentate ligands defining a pseudooctahedral [FeN6] coordination environment. R-L ligand induces the fac-Lambda isomer, while S-L ligand induces the fac-Delta isomer. Magnetic measurements reveal that both of them display obviously spin-crossover behavior at 365 K. After desolvation, they exhibit a reversible spin transition with a small hysteresis loop of ca. 3 K appearing at about T-1/2 up arrow = 222 K and T-1/2 down arrow = 219 K.
    No preview · Article · Sep 2013 · Inorganic Chemistry Communications
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    ABSTRACT: Two pairs of iron(II) chiral enantiomers fac-Δ-[Fe(S-L1)3][ClO4]2 and fac-Λ-[Fe(R-L1)3][ClO4]2 (Δ-1 and Λ-1), fac-Δ-[Fe(S-L2)3][ClO4]2 and fac-Λ-[Fe(R-L2)3][ClO4]2 (Δ-2 and Λ-2), L1 = (R/S)-(±)-1-naphthyl-N-(pyridine-2-ylmethylene)ethanamine, L2 = (R/S)-(±)-2-naphthyl-N-(pyridine-2-ylmethylene)ethanamine were synthesized and characterized by elemental analysis, IR, UV–Vis, CD and 1H NMR spectra. The X-ray structural analyses of Λ-1 and Δ-2 revealed that the iron(II) complexes possess octahedral coordination geometry for N6 donor atoms by three bidentate ligands. R-L1 ligand induces the fac-Λ isomer, while S-L2 ligand induces the fac-Δ isomer. The enantioselective binding of iron(II) chiral enantiomers to calf-thymus DNA (ct-DNA) has been investigated by methods of UV–Vis, fluorescence, and circular dichroism spectrometry. All the complexes could bind to ct-DNA and showed different binding affinities with the binding constants ranging from 0.91 × 105 to 1.43 × 105 M−1. Moreover, the Δ enantiomers exhibited more efficient DNA interaction with respect to the Λ enantiomers.
    No preview · Article · Mar 2013 · Polyhedron
  • Zhi-Guo Gu · Wen Zhou · Fei-Fei Bao · Chun-Yan Pang · Xin-Xin Xu · Zaijun Li
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    ABSTRACT: A new three-dimensional heterometallic MnIICuII azide-bridged coordination polymer, [Mn2Cu(N3)6(en)2]n (1), was synthesized by assembling MnII, CuII, azide, and ethylenediamine in solution condition. The 3D structure of 1 can be described as end-on (EO) azide-bridged Mn2Cu trinuclear units linked by end-to-end (EE) azide bridges. Magnetic analysis of 1 indicates that the EO- and EE-azide bridges mediate the ferromagnetic and antiferromagnetic exchange interactions, respectively, with the antiferromagnetic coupling dominating the magnetic properties.
    No preview · Article · Oct 2012 · Inorganic Chemistry Communications
  • Zhi-Guo Gu · Chun-Yan Pang · Zaijun Li · Hong-Ping Xiao
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    ABSTRACT: A new three-dimensional metal–organic framework, [Co3(cis-CHHC)(H2O)8]n·5nH2O (1), was synthesized by assembling Co(II) ion and all-cis 1,2,3,4,5,6-cyclohexanehexacarboxylate (cis-CHHC) ligand in hydrothermal condition. X-ray crystallography reveals that each cis-CHHC ligand connects six Co(II) atoms, and each Co(II) atom is linked to two cis-CHHC ligands, leading to a 3D structure with channels filled with lattice water molecules. Magnetic analysis of 1 indicates that the antiferromagnetic coupling dominates the magnetic properties.
    No preview · Article · Oct 2012 · Inorganic Chemistry Communications
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    Zhi-Guo Gu · Bao-Xiang Wang · Chun-Yan Pang · Fei-Fei Bao
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    ABSTRACT: In the centrosymmetric trinuclear cation of the title compound, [Co₃(C₄H(8)N₄)₆(H₂O)₆](C₁₀H₆O₆S₂)Cl₄, the three Co(II) atoms are bridged by six triazole mol-ecules via the N atoms in the 1,2-positions. The central Co(II) atom, lying on an inversion center, is coordinated by six triazole N atoms while the terminal Co(II) atoms are coordinated by three triazole N atoms and three water O atoms in a distorted octa-hedral geometry. The naphthalene-disulfonate anion is also centrosymmetric. The four chloride counter anions are half-occupied; the H atoms of the amino groups show an occupancy of 2/3. O-H⋯Cl, O-H⋯O and N-H⋯O hydrogen bonds link the complex cations and the chloride and naphthalene-1,5-disulfonate anions.
    Preview · Article · Jul 2012 · Acta Crystallographica Section E Structure Reports Online
  • Zhi-Guo Gu · Xin-Xin Xu · Wen Zhou · Chun-Yan Pang · Fei-Fei Bao · Zaijun Li
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    ABSTRACT: A fascinating polythreaded coordination network formed by 1D crankshaft shaped chains threading into a 2D undulated sheet in a one-over/one-under interweaving fashion was reported, in which the 2D layer exhibits an unusual polyknotted entanglement containing triple-stranded molecular braids.
    No preview · Article · Feb 2012 · Chemical Communications