Hua-Ze Dong

Self-assembly of copper and cobalt complexes with hierarchical size and catalytic properties for hydroxylation of phenol

A feasible and effective self-assembly method to synthesize different scale coordination polymers in highly dilute solution (from nanocrystals to microcrystals and to bulk crystals) without any blocking agent has been described. The growth of crystalline particles was controlled by removing the particles at different reaction times to interrupt the growth at the desired size. The nano and microscale particles show better catalytic conversions and selectivities in the hydroxylation of phenols than the bulk crystals.

Chemiluminescence behavior of CdTe-hydrogen peroxide enhanced by sodium hypochlorite and sensitized sensing of estrogens

It has been found that sodium hypochlorite enhanced the chemiluminescence (CL) of the CdTe nanocrystal (NC)-hydrogen peroxide system and that estrogens inhibited these CL signals in alkaline solution. CL spectra were used to investigate the mechanism of the CL enhancement. On the basis of the inhibition, a flow-injection CL method has been established for determination of three natural estrogens.

Syntheses, Structures, and Catalytic Properties of Five Isomorphous 3D Transition Metal Complexes Derived from Formate

Five isomorphous 3D complexes of formates, namely, {Cu(HCOO)2·4H2O}n (1), {Co(HCOO)2·2H2O}n (2), {Mn(HCOO)2·2H2O}n (3), {Co(HCOO)2·DMF·H2O}n (4), and {Mn2(HCOO)6·0.5[HN(CH3)2]}n (5), were synthesized and characterized by microanalysis. The catalytic activities of these complexes for the oxidation of phenol by H2O2 to catechol (CAT) and hydroquinone (HQ) were investigated. Complex 1 showed the best performance by exhibiting a high conversion rate of 68.02% and a high selectivity for CAT with a maximum CAT/HQ ratio of 2.74.

Syntheses and Structures of Three Divalent Zn/Cd Metal–Organic Supramolecular Frameworks Constructed by 1, 2, 4-benzenetricarboxylate

Three novel metal–organic hybrid compounds, [Zn(H2btc)2(H2O)2]·2H2O (1),[Cd(Hbtc) (H2O)]n (2) and [Zn3(btc)2(phen)2(H2O)2]n (3) (H3btc = 1,2,4- benzenetricarboxylate, phen = 1,10-phenanthroline), have been hydrothermally synthesized and their structures were determined by single-crystal X-ray diffraction. The structural motifs are multiforms from 0D, 3D, and 2D interpenetrating networks. It is found that the H3btc ligand exhibits multicoordinated modes. In these complexes, the carboxylates of btc and water molecules are involved in intermolecular hydrogen bondings to form the 3D molecular frameworks and reinforce the structural stability, which proves that noncovalent interactions like H-bond play an important role in instructing the supramolecular architectures.

Supramolecular Frameworks of Two Cadmium Complexes via Hydrogen-Bonding Assembly

Two novel complexes, [Cd(L)(NO3)2(H2O)2] (1) and [Cd(L)2(NO3)2] (2) constructed from 3-(dimethylamino)-1-(pyridine-4-yl)prop-2-en-1-one) (L), have been synthesized and characterized by elemental analyses and single crystal X-ray diffraction. The crystal structure analysis reveals that the cadmium (II) is a seven-coordinated ion in a distorted pentagonal bipyramid environment in complex 1, while the other Cd ion is an eight-coordinated ion in a pseudo square anti-prismatic environment in complex 2. Both complexes assembled into 3D hydrogen-bonding frameworks based on C-H···O, O-H···O hydrogen bond linkages.

Metallosupramolecular Silver and Zinc Complexes with Flexible or Semirigid Tripodal Pyridyl Pyrimidine Ligands

To explore the influence of different transition metal ions on the coordination geometries and structural architectures of metal organic complexes with flexible or semirigid tripodal ligands, [(Zn3C36H27N9S3I6)·(CHCl3)4](1), [C33H30N10S3Zn3Cl6] (2) and {[Ag2(C33H30N10S3)NO3]·NO3·H2O}n(3) were yielded by reactions of three tripodal ligands derived from pyridinyl-pyrimidine-2-thiol with ZnI2, ZnCl2 and AgNO3, respectively. The structural motifs of these complexes are multiforms from 0D to 3D interpenetrating networks. It is found that the conformational changes of ligands after interactions with metal salts are attributed to the positional isomerization of pyridine ring and effects of metal ions as well as anions. The pyridyl and pyrimidinyl rings act as N^N chelation or adopt monodentate mode in these complexes. The anions all take part in coordinating metal ions especially nitrates which can bridge silver ions to produce 1D structure in complex 3.

Ligand-Directed Molecular Architectures: Self-Assembly of Five (2+2) Metallacycles from Bis(4-(pyridin-2-yl)pyrimidin-2- ylthio)propane

Abstract{[Cd2(L1)2(NO3)2][Cd(NO3)3(H2O)2]2}·H2O (1), {[Cd(L1)(NO3)(CH3OH)]2(PF6)2}·H2O (2), {[Ni(L1)Cl(H2O)]·Cl·(H2O)3}2 (3), {[Ni2(HL1)2Cl4]2·(PF6)4·(CH3OH)3} (4), and {[Ni(L1)(DMF)2](PF6)2}2 (5) were assembled by reactions of a pyridyl-pyrimidine dithioether ligand L1 (L1=1,3-bis (4-(2-pyridyl)pyrimidin-2-ylthio)propane) with metal salts, respectively. Employment of different metals,different anions as well as solvents has induced the same [2+2] macrocyclic architectures, although free anions in complexes have been replaced by the addition of PF6− anions. All these demonstrate that L1 plays an important role in the self-assembling process. For all the structures, intermolecular and intramolecular hydrogen bonds were found to be instrumental in induction of multitopic organic ligands 3D supramolecular networks formation.Graphical AbstractThe synopsis of the table of contents: This work reports a design of self-assembly studies of [2+2] macrocyclic architectures using 1, 3-bis (4-(2-pyridyl) pyrimidin-2-ylthio)propane). Employment of different metals,different anions as well as solvents have resulted in similar crystal structures, although PF6− anions can substitute the free anions in complexes, which means the ligand plays an important role in the self-assembling process. In addition, intermolecular and intramolecular hydrogen bonds were found to be instrumental in leading to the formation of 3D supramolecular networks.

Supramolecular structures constructed from three novel rare earth metal complexes

AbstractThree rare earth metal supramolecular complexes, {[Tb(L2)4](ClO4)3⋅2H2O(1), [Eu(L2)2(H2O)5] (ClO4)3(2) and [Gd(NO3)3(L2)2] ⋅2CH3CH2OH(3) (L2 = 3-Dimethylamino-1-pyridin-2-yl-propenone), have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. The crystal structure analysis reveals that the coordination numbers of three complexes (1–3) are 8, 9 and 10, respectively. Three complexes assembled into 3D frameworks based on C-H ⋯O, O-H ⋯O hydrogen bond linkages. Graphical Abstract Three rare earth metal supramolecular complexes, {[Tb(L2)4](ClO4)3⋅2H2O(1)[Eu((L2)2(H2O)5](ClO4)3(2) and [Gd(NO3)3((L2)2]⋅2CH3CH2OH(3) ((L2=3-Dimethylamino-1-pyridin-2-yl-propenone), have been synthesized and characterized. The crystal structure analysis reveals that the coordination numbers are 8, 9 and 10, respectively. These complexes assembled into 3D hydrogen-bonding frameworks based on C-H···O, O-H···O linkages.

2-{[4-(Pyridin-2-yl)pyrimidin-2-yl]sulfan-yl}acetic acid.

In the title molecule, C11H9N3O2S, the pyridine and pyrimidine rings are almost parallel [dihedral angle = 6.7 (1)°]. In the crystal, adjacent molecules are joined by O—H⋯N and C—H⋯O hydrogen bonds, leading to the formation of a sheet parallel to (10).

cis-1,2-Bis{[4-(4-pyrid-yl)pyrimidin-2-yl]sulfanylmeth-yl}benzene.

The molecular skeleton of the title molecule, C26H20N6S2, adopts a cis conformation with the two arms positioned on one side of the benzene ring plane. Intramolecular π–π interactions between the pyrimidine rings [centroid–centroid distance = 3.654 (2) Å] and between the pyridine rings [centroid–centroid distance = 3.775 (2) Å] help to set the molecular conformation; the pyrimidine rings, as well as the pyridine rings, are nearly parallel, forming dihedral angles of 4.12 (14) and 2.46 (14)°, respectively.