Feng-Ying Bai

A novel family of 3D photoluminescent lanthanide–bta–flexible MOFs constructed from 1,2,4,5-benzenetetracarboxylic acid and different spanning of dicarboxylate acid ligands

By using 1,2,4,5-benzenetetracarboxylic acid as a rigid polycarboxylate metal linker and three types of flexible dicarboxylate ligands containing different –CH2– spacers as the second linker, a novel family of lanthanide MOFs (1–12) with three kinds of 3D framework structures, namely, [Ln2(ox)(bta)(H2O)4](Ln = Eu (1), Tb (2), Dy (3), Ho (4); H2ox = oxalic acid; H4bta = 1,2,4,5-benzenetetracarboxylic acid), [Ln2(glu)(bta)(H2O)4]·H2O (Ln = Tb (5), Eu (6), Dy (7), Ho (8); H2glu = glutaric acid), [Ln2(ad)(bta)(H2O)2] (Tb (9), Eu (10), Dy (11), Er (12); H2ad = adipic acid), have been synthesized under hydrothermal conditions. All coordination polymers were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that the networks of the twelve polymers exhibit a variety of coordination modes to metal centers and all have three dimensional structures. The photoluminescent properties for the polymers 1–3, 5–7 and 9–11 were examined by using luminescence spectra and the analysis results indicate that different spanning flexible linkers have different influence on the characteristic photoluminescence when the rigid linker is the same.

Two complexes (Cu, Zn) with 1,10-phenanthroline and a tridentate amino-Schiff-base: crystal structures, spectra, thermogravimetric analyses and superoxide dismutase activity

Two transition metal (Zn, Cu) complexes with a Schiff base (salicylideneglycine) and 1,10-phenanthroline: (C9H7NO3)Zn(C12H8N2)(H2O) (1) and (C9H7NO3)Cu(C12H8N2) (2) have been synthesized and characterized, including crystal structures, spectral characterization, thermogravimetric analyses and quantum chemistry calculations. X-ray crystallographic analysis shows the zinc to be six-coordinate mode, forming a slightly distorted octahedral geometry. The structure of 2 can be evaluated by the Addison distortion index (τ = 0.17), which indicates that the coordination environment of Cu is distorted slightly from square pyramidal (SP). The superoxide dismutase mimetic activity of the complexes was investigated by NBT-illumination. Complex 2 (IC50 = 6.15 µM) has better SOD–like activity than 1 (IC50 = 0.79 µM), although the SOD-like activity for 2 is not higher than some reported, it shows the possibility of SOD-like activity for the complexes with this amino-Schiff-base ligand (salicylideneglycine).

Synthesis, crystal structure, photoluminescence property and photoelectronic behavior of two uranyl-organic frameworks constructed from 1, 2, 4, 5-benzenetetracarboxylic acid as ligand

By using 1, 2, 4, 5-benzenetetracarboxylic acid as organic ligands, two uranyl coordination complexes, (UO2)2(bta)(DMA)2 (1) and [(UO2)2(bta)(μ3-OH2)]·2[HN(CH3)2]·H2O (2) (H4bta=1, 2, 4, 5-benzenetetracarboxylic acid, DMA=N,N-Dimethylacetamide) were synthesized. The X-ray single crystal analysis revealed that complex 1 exhibits a 3-demensional framework, while complex 2 exhibits a 2-demensional framework. In order to furthermore characterize the two complexes and extend their functional properties, spectroscopies of IR, UV-vis, photoluminescence and surface photovoltage were also studied primarily. In addition, thermogravimetric analyses and photocatalytic studies for complexes 1 and 2 were discussed in detail.

UO22+-amino hybrid materials: structural variation and photocatalysis properties

Four uranyl complexes (UO2)2(μ2-OH)(μ3-OH)(his)(CH3CO2) (his = histidine) (1), [(UO2)2(μ2-OH)(μ3-OH)2(gly)]·1.5H2O (gly = glycine) (2), UO2(CH3CO2)(μ2-OH)(2,2′-bipy) (3) and UO2(CH3CO2)2(2,2′-bipy) (4) were synthesized by the reaction of UO2(CH3CO2)2·2H2O as the metal source, and histidine, glycine and 2,2′-bipy as the ligand in an aqueous system. They were characterized by elemental analysis, IR, UV-vis, single crystal X-ray diffraction analysis and thermal gravimetric analysis. The structural analysis reveals that complex 1 exhibits a one-dimensional chain structure constructed by the building unit [(UO2)4O10(C6O2N3)2], which further extends the chain into 2D supramolecular architectures by hydrogen bonding interactions. For complex 2, uranyl polyhedrons, through edge-sharing, form a 2D wave-like layer and furthermore connect by hydrogen bonding to form a 3D supramolecular structure. Complex 3 is a discrete UO2-2,2′-bipy compound UO2(CH3CO2)(OH)(2,2′-bipy). Complex 4 is also a discrete UO2-acetic-2,2′-bipy compound UO2(CH3CO2)2(2,2′-bipy) which is similar to complex 3. The adjacent molecules were respectively connected by hydrogen bonding to form a 2D supramolecular network for 3 and a 1D supramolecular chain for 4. In order to determine their functional properties, their photoluminescence was characterized and their photocatalytic properties were also studied firstly.

Multi-functional d10 metal–organic materials based on bis-pyrazole/pyridine ligands supported by a 2,6-di(3-pyrazolyl)pyridine with different spanning flexible dicarboxylate ligands: synthesis, structure, photoluminescent and catalytic properties

A series of the novel zinc complexes, Zn3(H2L1)2(ox)3(H2O)2·4H2O (1), Zn(H2L1)(ad)·2H2O (2), Zn2(HL2)2(suc)0.5·(HCOO)·H2O (3), Zn2(HL2)2(glu)·2H2O (4), Zn2(HL2)2 (ad)0.5·(OH)·0.5H2O (5), Zn2(HL2)2(seb)(H2O)·2.5H2O (6), (H2L1 = 2,6-di(5-methyl-1H-pyrazol-3-yl)pyridine, H2L2 = 2,6-di(5-phenyl-1H-pyrazol-3-yl)pyridine, H2ox = oxalic acid, H2ad = adipic acid, H2suc = succinic acid, H2glu = glutaric acid, H2seb = suberic acid) were synthesized hydrothermally from the self-assembly of a Zn(II) ion with different types of the new bi-pyrazolyl pyridine derivative ligands and different spanning flexible dicarboxylic compounds as an auxiliary ligand. They were characterized by elemental analysis, IR and UV–vis spectroscopy, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. We found that they are all molecular compounds using the above detections. The structural analysis indicates that the zinc atom in complex 1 is a six-coordinate mode of ZnO3N3, forming a slightly distorted octahedral geometry, while zinc atoms in complexes 2–6 are all penta-coordination modes of ZnO2N3 and ZnON4 in a distorted bipyramidal geometry. The H2L1 ligand is in the form of a μ1–η1–η1–η1 coordination with metallic Zn in 1 and 2; while the HL2 ligand is in a μ2–η1–η1–η1–η1 coordination mode in 3–6. For the oxalate ligand, there are two kinds of coordination modes, μ2–η1–η1–η1–η1 bridging coordination mode and μ1–η1–η1 terminal coordination mode; the coordination mode of glutaric acid ligand is in the form of μ2–η1–η1; suc2− ligand is in the form of a μ4-bridging coordination fashion with each side carboxylate group in a μ2–η1–η1-monodentate mode; the coordination of the adipic acid ligand presents two coordination modes of μ2–η1–η1and μ4–η2–η2; suberic acid ligand acts in a monodentate terminal coordination mode. In addition, thermal behaviors and photoluminescent properties for 1–6 were all performed and are discussed in detail. The catalytic activity of the complexes is evaluated firstly by the reaction of hydrogen peroxide promoted oxidation of cyclohexane and cyclopentane under mild conditions. It is found that the Zn complexes with five different spanning flexible dicarboxylic acids as an auxiliary ligand with oxalic acid, succinic acid, glutaric acid, adipate acid or sebacic acid, respectively, have potential catalytic activity in the oxidation reaction of cyclohexane.

A melamine–adipate-bridged binuclear copper complex with supramolecular architecture: synthesis, structures, and properties of [Cu2(MA)(ad)2]·H2O and (MA)·(H2ad)·H2O

Complexes of melamine with adipic acid and Cu(CH3COO)2 · H2O, [Cu2(MA)(ad)2] · H2O (1), and (MA) · (H2ad) · H2O (2) (MA = melamine; H2ad = adipic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared, UV-Vis, and single crystal X-ray diffraction. Both crystallized in the triclinic space group P-1. In 1, MA and adipate bond to copper to construct a 3-D supramolecular framework in an unusual noninterpenetrated pseudo-primitive cubic topology constructed from a four-connected binuclear Cu(II) secondary building unit. A variety of intra- or inter-molecular hydrogen bonds exist. In 2, the 3-D supramolecular structure is formed through strong interactions among MA, adipic acid, and lattice water. Thermal analysis, photoluminescence, and calculations were also performed.

Synthesis, structures and properties of the catalytic bromination reaction of a series of novel scorperate oxidovanadium complexes with the potential detection of hydrogen peroxide in water.

A series of scorpionate oxovanadium (IV) complexes: [VO(Tp(4I))(pz)(SCN)]·1/2CH2Cl2 (1), [VO(Tp)(pzTp)]·2H2O (2), [VO(Bp)(Tp(4I))] (3) and [VO(C5H7O2)(Tp(4I))]·CH3OH (4) (Bp: [H2B(pz)(2-)], Tp: [HB(pz)(3-)], Tp(4I): [HB(4I-pz)(3-)], pzTp: [B(pz)(4-)]) have been synthesized and characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction and thermal gravimetric analysis (TG). Structural analysis shows that the coordination environment of vanadium atom is N5O, to form a distorted octahedron geometry. In addition, the catalytic activities of the bromination reactions for complexes 1 and 2 in phosphate buffer with phenol red as a trap were evaluated primary by UV/Vis spectroscopy, and a practical application of H2O2 detection was firstly observed in the catalytic reaction system.

Synthesis, structure, and catalytic bromination of supramolecular oxovanadium complexes containing oxalate

Three supramolecular complexes, [VO(phen)(C2O4)(H2O)]·CH3OH (1) [(VO)2(u2-C2O4)(C2O4)2(H2O)2]·L·H2O (2), and [(4,4′-bipyH2)0.5]+[VO2(2,6-dipic)]−·2H2O (3) (phen = 1,10-phenanthroline 4,4′-bipy = 4,4′-bipyridine, 2,6-dipic = 2,6-pyridinedicarboxylic, L = 1,4-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzene), have been prepared and characterized by elemental analysis, IR, and UV–vis spectroscopy and single-crystal diffraction analysis. Structural analysis shows that the three complexes all contain carboxylate and V=O moiety; vanadium of 1 and 2 are six coordinate with distorted octahedral geometry with N2O4 and O6 donor sets, respectively, while 3 is five coordinate with distorted trigonal bipyramidal geometry with a NO4 donor set. The complexes exhibit catalytic bromination activity in the single-pot reaction for the conversion of phenol red to bromophenol blue in H2O–DMF at 30 ± 0.5 C with pH 5.8, indicating that they can be considered as functional model vanadium-dependent haloperoxidases. In addition, electrochemical behaviors are also studied.

Photocatalytic activity of the modified composite photocatalyst by introducing the rich-nitrogen complex to the Bi2WO6

A metal-organic complex [Cd2(L)(N3)4]·DMF was prepared by the reaction of Cd(NO3)2·4H2O, NaN3 and ligand L (L: 1,4-bis(bis(3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzene) in a DMF system. And the complex was characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, thermal gravimetric technology, X-ray powder diffraction and single-crystal X-ray diffraction. Furthermore, the complex was combined with Bi2WO6 to form a composite, which was used as photocatalyst to degrade the basic dye methylene blue (MB) under the Xe lamp irradiation. The result revealed that the photocatalytic activity of the composite was better than that of the pure Bi2WO6 and the complex. In addition, the mechanism of the photocatalysis was also studied.

Optical detection of small biomolecule thiamines at a micromolar level by highly luminescent lanthanide complexes with tridentate N-heterocyclic ligands

A new series of lanthanide complexes Ln(H2L)(EtOH)(NO3)3 (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), and Tb (8)) have been synthesized by a solution synthetic method, heating in a pyrex flask, from the self-assembly of lanthanide ions (Ln3+) with tridentate N-heterocyclic ligand 2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine (H2L). These complexes were characterized by elemental analysis, IR spectra, powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, thermal gravimetric analysis (TG) and luminescence spectra. In particular, the complexes Eu(H2L)(EtOH)(NO3)3 (6) and Tb(H2L)(EtOH)(NO3)3 (8) emit strong luminescence with high efficiency. Based on the luminescent properties of the lanthanide complexes, we found that very fast and extremely sensitive optical detection of the thiamines can be achieved for the first time, using the better performing luminescent sensing materials. The quenching constant (KSV) of complex 6 was 9.08 × 105 M−1 for TPP, 4.90 × 105 M−1 for TMP, and 4.17 × 105 M−1 for TCl. The KSV of complex 8 was 1327 M−1 for TPP, 149 M−1 for TMP, and 132 M−1 for TCl. The lower detection limit of complex 6 was 0.029 μM for TPP, 0.027 μM for TMP, and 0.028 μM for TCl, and the highest quenching efficiency was 99.92% for TPP, 99.85% for TMP and 99.82% for TCl. For complex 8, the lower detection limit was 0.090 μM for TPP, 0.278 μM for TMP, and 0.263 μM for TCl, and the highest quenching efficiency was 86% for TPP, 38% for TMP and 35% for TCl. The greater KSV values, the lower detection limits, and the higher quenching efficiencies revealed extremely high sensitivity, showing both complexes 6 and 8 to be some of the best sensitive luminescence based metal–organic detectors of TPP, TMP and TCl. In the meantime, possible energy transfer mechanisms are discussed.