Synthesis and Characterization of the First Dinuclear Europium(Ⅱ) Complex Supported by Carbon-Bridged Biphenolate Ligand

Anhydrous EuCl3 reacted with sodium carbon-bridged biphenolate LNa2[ L = 2,2＇-methylene bis（6-tert-butyl-4- methyl-phenoxo ] in a 1 ： 1 molar ratio in THF in the presence of HMPA （HMPA = hexamethylphosphoric triamide）, then the product formed in situ was reduced by Na-K alloy to generate the divalent carbon-bridged biphenolate europium complex [ LEu （HMPA） 2 ] 2 （THF） 4 （ 1 ） in a good isolated yield. Complex 1 was fully characterized by elemental analysis, NMR and IR spectra, and X-ray structural determination. The crystal data of complex 1 are monoclinic, P2 1/c space group, a=1.6521（3） nm, b=2.8274（3） nm, c=1.2074（2） nm, β=111.723（6）°, V=5.2393（14） nm^3, Z=2, Dc= 1.259 mg·m^-3, μ = 1.304 mm^-1, F（000） = 2092, R = 0.0815, wR = 0. 1723. Complex 1 is a dimer with two Eu - O bridges. The coordination geometry of each europium atom can be best described as a distorted trigonal bipyramid.

Cloud-point extraction and preconcentration of bisphenol A from water samples

A novel cloud-point extraction （CPE） was successfully used in preconcentration of biphenol A （BPA） from aqueous solutions. Majority of BPA is extracted into the surfactant-rich phase. The parameters affecting the CPE such as concentration of surfactant and electrolyte, equilibration temperature and time and pH of sample solution were investigated. The samples were analyzed by high-performance liquid chromatography with ultraviolet detection. Under the optimized conditions, preconcentration of 10 mL sample gives a preconcentration factor of 11. The limit of detection （LOD） and limit of quantification （LOQ） are 0.1 μg/L and 0.33 μg/L, respectively. The linear range of the proposed method is 0.2-20 μg/L with correlation coefficients greater than 0.998 7 and the spiking recove6es are 97.96%-100.42%. The interference factor was tested and the extraction mechanism was also investigated. Thus, the developed CPE has proven to be an efficient, green, rapid and inexpensive approach for extraction and preconcentration of BPA from water samples.

Synthesis,Structure and Characterization of a 3D Chiral Carboxylate and Phosphonate Metalorganic Framework Based on 1,1?-Biphenol Ligand

A novel phosphonate-based chiral metal-organic framework 1 was synthesized from C2-symmetric 1,1？-biphenol-based ligand and structurally characterized by single-crystal and powder X-ray diffraction, Fourier-transform infrared spectra（FTIR）, circular dichroism（CD） and thermogravimetric analyses（TGA）. Two neighboring Mn ions are linked by two carboxylate groups and one phosphate group to form a di-manganese unit [Mn2] and each [Mn2] cluster in 1 is linked by five ligands, generating a 3D network with fns topology. In addition, the photoluminescence properties of 1 and H4 L were investigated.

A high potential biphenol derivative cathode: toward a highly stable air-insensitive aqueous organic flow battery

Aqueous organic flow batteries have attracted dramatic attention for stationary energy storage due to their resource sustainability and low cost. However, the current reported systems can normally be operated stably under a nitrogen or argon atmosphere due to their poor stability. Herein a stable airinsensitive biphenol derivative cathode, 3,30,5,50-tetramethylaminemethylene-4,40-biphenol(TABP), with high solubility(>1.5 mol L^(-1)) and redox potential(0.91 V vs. SHE) is designed and synthesized by a scalable one-step method. Paring with silicotungstic acid(SWO), an SWO/TABP flow battery shows a stable performance of zero capacity decay over 900 cycles under the air atmosphere. Further, an SWO/TABP flow battery manifests a high rate performance with an energy efficiency of 85% at a current density of60 m A cm^(-2) and a very high volumetric capacity of more than 47 Ah L^(-1). This work provides a new and practical option for next-generation practical large-scale energy storage.

Electrocatalytic Synthesis of Non-Symmetric Biphenols Mediated by Tri(p-bromophenyl)amine:Selective Oxidative Cross-Coupling of Different Phenols and Naphthols

An efficient electrochemical access to the non-symmetric biphenols using tri(p-bromophenyl)amine(TBPA)as a redox mediator has been developed.The electrochemical protocol features highly selective cross-coupling products in up to 83% yield,instead of forming homo-coupling ones.

Synthesis,structure and catalytic activity of complexes [Ln(EDBP)_2(DME)Na(DME)_3](Ln=Er,Yb,Sm) for ring-opening polymerization of ε-caprolactone

Discrete ion-pair complexes [Ln(EDBP)2(DME)Na(DME)3] [Ln=Er (1), Yb (2), Sm (3)] have been synthesized by the reaction between sodium salt of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol)(EDBPH2) and Ln(BH4)3·3THF (Ln=Er, Yb, Sm) followed by centrifugation and recrystalization. The complexes were characterized by elemental analysis and FT-IR, and the bonding model of these compounds was confirmed by X-ray single crystal diffraction for complex 1. It was found that four O atoms in two biphenol ligands as well as two O atoms in one ethylene glycol dimethyl ether (DME) molecule connect to the center rare earth metal atom, while sodium exists as counterpart cation to balance the charge. Complexes 1―3 can all be used as single component initiators for the ring-opening polymerization of ε-caprolactone.

RARE EARTH COMPLEXES[Ln(EDBP)_2(DME)Na(DME)_3]AS CATALYSTS FOR THE POLYMERIZATION OF 2,2-DIMETHYLTRIMETHYLENE CARBONATE

The biphenol based discrete ion-pair rare earth complexes, [Ln（EDBP）2（DME）Na（DME）3] [Ln = Er（1）, Yb（2）, Sm（3）], were prepared and used as catalysts for the ring-opening polymerization （ROP） of 2,2-dimethyltrimethylene carbonate （DTC）. Three complexes show moderate activities for the polymerization, and the catalytic activities increase in the following sequence： （Yb 〈 Er 〈 Sm）. The effect of different ratios of [DTC]/[Ln], polymerization temperature and time on the polymerization was investigated. Moreover, PDTC without ether unit developed from possible CO2 elimination was prepared.