Zhi-Gang Li

An Efficient Ullmann-Type C−O Bond Formation Catalyzed by an Air-Stable Copper(I)−Bipyridyl Complex

An efficient O-arylation of phenols and aliphatic alcohols with aryl halides was developed that uses an air-stable copper(I) complex as the catalyst. This arylation reaction can be performed in good yield in the absence of Cs2CO3. A variety of functional groups are compatible with these reaction conditions with low catalyst loading levels.

Copper(I)-Catalyzed Aryl Bromides To Form Intermolecular and Intramolecular Carbon−Oxygen Bonds

A highly efficient Cu-catalyzed C-O bond-forming reaction of alcohol and aryl bromides has been developed. This transformation was realized through the use of copper(I) iodide as a catalyst, 8-hydroxyquinoline as a ligand, and K(3)PO(4) as a base. A variety of functionalized substrates were found to react under these reaction conditions to provide products in good to excellent yields.

Metal–organic frameworks based on the pyridine-2,3-dicarboxylate and a flexible bispyridyl ligand: syntheses, structures, and photoluminescence

Three new metal–organic coordination polymers, [Cu(2,3-pydc)(bpp)]·2.5H2O (1), [Zn(2,3-pydc)(bpp)]·2.5H2O (2) and [Cd(2,3-pydc)(bpp)(H2O)]·3H2O (3) (2,3-pydcH2 = pyridine-2,3-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized at room temperature. All complexes have metal ions serving as 4-connected nodes but represent two quite different structural motifs. Complexes 1 and 2 are isomorphous, both of which feature 2D → 3D parallel interpenetration. Each two-dimensional (2D) layer with (4, 4) topology is interlocked by two nearest neighbours, one above and one below, thus leading to an unusual 3D motif. Complex 3 has a non-interpenetrating 3D CdSO4 framework with cavities occupied by uncoordinated water molecules. The compounds have been characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and X-ray crystallography. The photoluminescent studies of 2 and 3 show that both complexes exhibit intense fluorescent emissions at room temperature.

Construction of coordination networks with high connectivity: a new 8-connected self-penetrating network based on tetranuclear metal clusters

Two highly connected cobalt(II) and zinc(II) coordination polymers with tetranuclear metal clusters as the nodes of network have been prepared, being the first example of an 8-connected self-penetrating net based on a cross-linked α-Po subnet.

Supramolecular isomerism in zinc hydroxide coordination polymers with pyridine-2,4-dicarboxylic acid: Two polymorphs with centrosymmetric two-dimensional and acentric three-dimensional coordination networks

Reactions of Zn(BF4)2 and pyridine-2,4-dicarboxylic acid (2,4-pydcH2) in the presence of 1,2-bis(4-pyridyl)ethylene or 1,3-bis(4-pyridyl)propane under hydro(solvo)thermal conditions yielded two polymorphic metal–organic coordination polymers formulated as Zn2(OH)2(2,4-pydc) (1 and 2). Polymorph 1 features a two-dimensional (2-D) layer-like structure that is constructed by 2,4-pydc ligands bridging between the Zn–OH–Zn double-chain units. Each single Zn–OH–Zn chain is composed of μ2-OH groups connecting trigonal bipyramidal and tetrahedral Zn centers. Polymorph 2 is a 3-D coordination polymer containing 2-D Zn–OH–Zn sheets that consist of μ2- and μ3-OH groups and trigonal bipyramidal Zn centers. The sheets are pillared by 2,4-pydc ligands to form an acentric structural architecture. 1 and 2 are rare examples that the two polymorphs exhibit a centrosymmetric 2-D coordination network and an acentric 3-D coordination network, respectively. The different structures lead to differences in photoluminescent properties and thermal stabilities for 1 and 2.

Constructing porous frameworks from one-dimensional cobalt-oxygen clusters and pyridinedicarboxylate ligands adopting two rare coordination modes

A porous material with cobalt–oxygen cluster framework has been synthesized hydrothermally, which possesses large and rigid channels and manifests strong antiferromagnetic interactions, and the pyridinedicarboxylate ligand exhibits two types of rare coordination modes.

catena-Poly[diammonium [diaqua­bis(pyridine-2,4-dicarboxyl­ato-κ2N,O2)cuprate(II)] [[diaqua­copper(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3N,O2:O2′-[tetra­aqua­cadmium(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3O2:N,O2′] hexa­hydrate]

The title mixed-metal complex, {(NH4)2[Cu(C7H3NO4)2(H2O)2][CdCu(C7H3NO4)2(H2O)6]·6H2O}n, contains one octahedrally coordinated CdII center and two octahedrally coordinated CuII centers, each lying on an inversion center. The two CuII atoms are each coordinated by two O atoms and two N atoms from two 2,4-pydc (2,4-H2pydc = pyridine-2,4-dicarboxylic acid) ligands in the equatorial plane and two water molecules at the axial sites, thus producing two crystallographically independent [Cu(2,4-pydc)2(H2O)2]2− metalloligands. One metalloligand exists as a discrete anion and the other connects the Cd(H2O)4 units, forming a neutral chain. O—H⋯O and N—H⋯O hydrogen bonds connects the polymeric chains, complex anions, ammonium cations and uncoordinated water molecules into a three-dimensional supramolecular network.

Tetra­aqua­(1,10-phenanthroline-κ2N,N′)cobalt(II) dinitrate: a hydrogen-bonded supra­molecular network

The structure of the title compound, [Co(C12H8N2)(H2O)(4)]-(NO3)(2), consists of tetraaqua(1,10- phenanthroline)cobalt(II) cations and nitrate anions. The Co atom is located on a twofold rotation axis and is coordinated by the two N atoms of a 1,10-phenanthroline ligand and four O atoms of water molecules. The cations and anions are linked by hydrogen-bond interactions into a three-dimensional supramolecular network.

(E)-quinoline-4-carbaldehyde oxime

The title compound, C10H8N2O, exists as the E isomer. The crystal packing is stabilized by intermolecular O - (HN)-N-... and C - (HN)-N-... hydrogen bonds, as well as pi-pi stacking.

Poly[di-μ3-chloro-μ2-trans-1,2-di-4-pyridylethyl­ene-dicopper(I)]: a two-dimensional organic–inorganic hybrid constructed from linear CuCl clusters and bridging ligands

The structure of the title compound, [Cu2Cl2(C12H10N2)](n), contains infinite CuCl staircase-like chains, which lie about inversion centres. The trans-1,2-di-4-pyridylethylene molecules also lie about inversion centres and connect the CuCl chains through Cu-N coordination bonds into a two-dimensional organic-inorganic hybrid network. The planar sheets are stacked along the c axis and associated through weak C-H...Cl interactions. The results show a reliable structural motif with controllable separation of the CuCl chains by variation of the length of the ligand.