Shilong Yang

A natural quercetin-based fluorescent sensor for highly sensitive and selective detection of copper ions

A natural quercetin-based fluorescent sensor for highly sensitive and selective detection of copper ions has been studied. The quercetin fluorescent sensor after binding to Cu2+ ions in pH 7.40 buffered solution showed a quenching of fluorescence emission intensity. The binding constant value was obtained as 3.56 × 107. The sensor can be applied to the quantification of Cu2+ ions with a linear range of 2.0 × 10−7–3.0 × 10−6 mol L−1 and a detection limit of 1.0 × 10−7 mol L−1. The sensor showed high selectivity toward Cu2+. As a result, the proposed fluorescent sensor was successfully applied for determination of Cu2+ in water samples.

Highly selective carbon dioxide uptake by a microporous kgm-pillared metal-organic framework with acylamide groups

A microporous acylamide-functionalized metal–organic framework with a kgm-pillared structure, [Cu(NAIP2−)]n, has been designed by self-assembling [Cu2(COO)4] paddlewheel SBUs and a novel trigonal heterofunctional ligand with a linking acylamide group. [Cu(NAIP2−)]n exhibits a moderate BET surface area of 1060 m2 g−1, high CO2 uptake (4.5 wt% at 0.15 bar and 298 K; 201.8 cm3 g−1 at 20 bar and 298 K) and high selectivity for CO2 over CH4 (8.34) and N2 (38.3) at 273 K.

Synthesis, structure, and luminescence of a coordination polymer from fumaropimaric acid and a water cluster

Using fumaropimaric acid (H3L) as the ligand, a coordination polymer {[Cd(H2L)2(H2O)2]·8H2O}n was synthesized under solvothermal conditions and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. In the complex, Cd(II) is eight-coordinate with a distorted dodecahedral CdO8 geometry. There is a Cd2L2 chelate ring, which forms an infinite 1-D chain structure along the b axis. The 1-D chains are further linked by strong O–H···O hydrogen bonding of a water cluster to form a 2-D structure. A dodecamer water cluster consisting of a five-membered ring with envelope conformation is the first reported. The complex is the first example showing three completely different coordination modes of carboxyl groups for Cd(II) complexes. The complex displayed medium fluorescence emission peaks at ca. 442 nm. Graphical Abstract

Isolation, characterization and in vitro anticancer activity of an aqueous galactomannan from the seed of Sesbania cannabina

As a pioneer plant, Sesbania cannabina is cultivated on a large scale for saline-alkali land improvement in China. Here, a native galactomannan (GalM) and a series of its hydrolysates (GalM40, GalM50 and GalM65) were obtained from S. cannabina seed by water extraction, β-mannanase hydrolysate and ethanol precipitation. As elucidated by HPAEC, NMR, FT-IR and HPGPC, GalM was characterized as a β-1,4-linked d-mannose polymer with single α-1,6-linked d-galactose side chain in a 2.4:1M ratio, and had a molecular weight of 1.42×106Da. MTT assay showed that these four fractions had significant inhibitory effect on A549, Hela, HepG2 and MCF-7 in a dose-dependent manner, and that GalM40 with second-highest MW (1.47×104Da) possessed higher activity amongst those fractions. Such strong inhibition effect on the growth of human cancer cells might derive from its ability to increase caspase-12 expression, as revealed from immunohistochemical analysis. In sum, this paper characterizes the molecular structure of S. cannabina galactomannan with anticancer activity, and this new knowledge will provide a basis for its further structure-properties research and ultimately, develop new possibilities for its use in high-value applications, such as functional food.

Quercetin-coated Fe3O4 nanoparticle sensors based on low-field NMR for determination and removal of Pb2+ and Cu2+ in biological samples

In this paper, we develop quercetin-coated Fe3O4 nanoparticles (QMNPS) as a sensor for the detection and removal of Pb2+ and Cu2+ based on low-field NMR. QMNPS were characterized by TEM, FTIR and XRD. The NMR sensor showed high selectivity toward Pb2+ or Cu2+. The standard curves for ΔT2-ion concentration showed good correlations, i.e., R2 = 0.9912 for Pb2+ and 0.9983 for Cu2+; the linear ranges and the limits of detection were 4.8 × 10−6–1 × 10−4 mol L−1 and 1.6 × 10−6 mol L−1 for Pb2+, and 5.0 × 10−6–1 × 10−4 mol L−1 and 2.0 × 10−6 mol L−1 for Cu2+, respectively. The calculated maximum adsorption capacity was about 71 mg for Cu2+ and 68 mg for Pb2+ per gram of QMMP, which was superior to the results of some previous reports. The detection and removal of Pb2+ or Cu2+ was based on the coordination reaction between the NMR sensor of QMNPs and Pb2+ or Cu2+, which led to the aggregation of QMNPs. As a result, the proposed NMR sensor was successfully applied for the determination and removal of Pb2+ and Cu2+ in contaminated water and urine samples with excellent recoveries and high adsorbent capacities.

Crystal structure, electrochemical and magnetic properties of a new binuclear copper(II) complex with benzoic acid as a ligand

A new complex [Cu2(L)4(DMF)2] (1) with benzoic acid (HL) as a ligand is synthesized by the solid phase synthesis method. Crystal data for the complex are as follows: monoclinic, space group P21/n, a = 10.593(2) Å, b = 10.123(2) Å, c = 16.336(3) Å, β = 93.55(3)°, V = 1748.4(6) Å3, Dc = 1.439 g/cm–3, Z = 4, F(000) = 780, GOOF = 1.003, final discrepancy factors R1 = 0.0624, wR2 = 0.1559. In 1, the Cu(II) ion is coordinated by six oxygen atoms to give a distorted octahedral coordination geometry. The electrochemical, fluorescent, and magnetic properties of 1 are studied. The results show that the electron transfer of 1 is quasi reversible in the electrode reaction corresponding to Cu(II)/Cu(I), and 1 exhibits three relatively strong fluorescent emission peaks at 403, 425, and 454 nm. In addition, complex 1 displays antiferromagnetism in a temperature range of 300 ~ 10 K.