Can-Zhong Lu

A New Transparent Conductor: Silver Nanowire Film Buried at the Surface of a Transparent Polymer

With the emergence of fl exible plastic devices and the scarcity of indium resources, great efforts have been made to develop new fl exible transparent conductors to replace indium tin oxide (ITO), [ 1,2 ] examples including conductive polymers, [ 3,4 ] carbon nanotubes (CNTs), [ 5–8 ] graphene, [ 9 ] metal grids, [ 10 ] and random networks of metallic nanowires. [ 11,12 ] Among these contenders, random silver nanowire (AgNW) networks show optoelectronic performances very close to that of ITO [ 11 , 13 ] and are regarded as the leading candidate material to replace ITO [ 14 ] (Table 1S in Supporting Information). There are two critical issues that currently prohibit AgNW fi lms from large scale applications: AgNW fi lms deposited on bare substrates are highly coarse [ 12 ]

Assembly of a metal-organic framework by sextuple intercatenation of discrete adamantane-like cages

Metal-organic frameworks form a unique class of multifunctional hybrid materials and have myriad applications, including gas storage and catalysis. Their structure is usually achieved through the infinite coordination of metal ions and multidentate organic ligands by means of strong covalent bonds. Threaded molecules such as catenanes and rotaxanes have largely been restricted to comprising components of two-dimensional interlocking rings or polygons. There are very few examples of the catenation of polyhedral cages. Although it has been postulated that the infinite extended architecture can be obtained from the polycatenation of a discrete cage based on such threading, this has not been documented to date. Here we describe an infinite three-dimensional metal-organic framework composed of catenated polyhedral cages, in which the framework is achieved by mechanical interlocking of all of the vertices of the cages. The three-dimensional polycatenated framework shows twofold self-interpenetration in its crystal packing. The penetration of polycatenanes creates nanosized voids into which the Keggin polyoxometalate anions are perfectly accommodated as counteranions.

A novel left-handed double helicate constructed from l-tartrate bridged molybdenum(vi) and gadolinium(iii) atomsElectronic supplementary information (ESI) available: crystallographic data, TGA, powder X-ray patterns, ORTEP structure and molar susceptibility plot for compound 1. See http://www.rsc.org/suppdata/cc/b3/b301542d/

The one-dimensional double helicate, [NH4][Mo2O4Gd(H2O)6(L-C4H2O6)2] x 4H2O (1), which was synthesized by the reaction of GdCl3, L-tartaric acid and ammonium molybdate in acidified water solution, is built up by two heft-handed single-helical chains, linked up further by eight-coordinated GdIII pieces in an enantiopure left-handed double helical configuration, of which each helix is formed by L-tartrate bridged six-coordinated MoVI atoms.

Surface modification of polyoxometalate host-guest supramolecular architectures: from metal-organic pseudorotaxane framework to molecular box

Precise controlling of the pH value leads to the formation of a new type of metal-organic pseudorotaxane framework and supramolecular box within accommodating POMs guests.

New optical supramolecular compound constructed from a polyoxometalate cluster and an organic substrate

A new optical supramolecular compound constructed from a polyoxometalate cluster and an organic substrate [(H3O)(C12H10N3)2(PW12O40)] (1) has been synthesized via a hydrothermal reaction and has been structurally characterized by X-ray diffraction. The solid-state diffuse reflectance, IR, and photoluminescence spectra of the title compound indicate that there is an interaction between the alpha-PW12O40 and the organic substrate. The light-yellow title compound shows a certain second-order nonlinear optical response of I(2omega) = 2I(KDP)(2omega).

Multifunctional Radical-Doped Polyoxometalate-Based Host–Guest Material: Photochromism and Photocatalytic Activity

An effective strategy to synthesize multifunctional materials is the incorporation of functional organic moieties and metal oxide clusters via self-assembly. A rare multifunctional radical-doped zinc-based host-guest crystalline material was synthesized with a fast-responsive reversible ultraviolet visible light photochromism, photocontrolled tunable luminescence, and highly selective photocatalytic oxidation of benzylic alcohols as a result of blending of distinctively different functional components, naphthalenediimide tectons, and polyoxometalates (POMs). It is highly unique to link π-electron-deficient organic tectons and POMs by unusual POMs anion-π interactions, which are not only conducive to keeping the independence of each component but also effectively promoting the charge transfer or exchange among the components to realize the fast-responsive photochromism, photocontrolled tunable luminescence, and photocatalytic activity.

The Structure and Physical Properties of a Novel Three-Dimensional Zeolite-Like Nanoporous Architecture Formed by Two Different Polymeric Layers: [Eu2(btc)(H2btc)(H2O)]·4H2O

The open framework of [Eu2(btc)(H2btc)(H2O)]·4H2O (1), prepared by hydrothermal reaction of EuCl3 with 1,2,4,5-benzenetetracarboxylic anhydride in acidified aqueous solution, is built up from two types of polymeric layers with [EuO6(H2O)]n units as tethers, resulting in nanoporous channels that host water molecules through complex hydrogen bonding. Crystallographic data for 1: monoclinic, P21/n, with a = 10.7562(2) A, b = 7.2075(2) A, c = 17.2180(5) A, β = 97.072(2)° and Z = 2. A study of the temperature dependence of the magnetic susceptibility data reveals that the paramagnetic behavior of 1 is mainly due to the effective spin-orbital coupling between the ground and exited states through the Zeeman perturbation; the magnetic interaction between europium(III) centers is very weak. A study of the electronic properties demonstrates that compound 1 is a semiconductor. A TGA analysis between 30 and 600 °C for 1 suggests that when the lattice water molecules are removed from the network, the skeleton of the network still remains stable up to 150 °C; this is also confirmed by XRPD. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

PH-controlled construction of Cu(I) coordination polymers: in situ transformation of ligand, network topologies, and luminescence and UV-vis-NIR absorption properties.

Two new complexes [Cu(I)(3)(L1)I(3)](n) (1, L1 = 2,5-bis(4-pyridyl)-1,3,4-oxadiazole) and [Cu(I)(3)(L2)I(2)](n) (2, L2 = 2,5-bis(4-pyridyl)-1,2,4-triazolate) are controllably formed by using aqueous ammonia to regulate the pH value of the reaction involving CuI and L1. Interestingly, L2 of 2 is in situ generated from the ring transform of L1 when increase the pH value of the reaction. 1 exhibits 2-D layer, while 2 shows 3-D MOFs with a novel 3-nodal 4,4,5-connected net topology of an unprecedented Point (Schlafli) symbol: (4·5(2)·6(2)·7)(5(4)·8(2))(4(3)·5·6(6)). Although both 1 and 2 are built of CuI and similar ligands, different arrangements of CuI chains and ligands endow them with different physical properties. 1 displays a strong pure red luminescence emission, while 2 is nonluminescent and shows a broad absorption band covering the whole UV-vis-NIR spectrum range. The emissive excited states of 1 and the charge transitions of the optical absorption for 2 are solved by DFT calculations.

Stoichiometry, temperature, solvent, metal-directed syntheses of metal–organic frameworks based on flexible V-shaped methylenebis(3,5-dimethylpyrazole) and various aromatic dicarboxylate acids

Seven new metal–organic frameworks (MOFs), namely, {[Cd2(NDC)2(H2MDP)](H2O)} (1), [Cd(NDC)(H2MDP)] (2), {[Cd2(NDC)(HNDC)2(H2MDP)2](H2O)0.5} (3), [Cd(NH2–BDC)(H2MDP)2] (4), [Cd(NH2–BDC)(H2MDP)2] (5), [Cd(H2MDP)(Br–BDC)0.5(Br–HBDC)] (6), {[Co(H2MDP)(Br–BDC)](H2O)0.5} (7) (H2MDP = methylenebis(3,5-dimethylpyrazole), H2NDC = 1,4-naphthalenedicarboxylic acid, NH2–H2BDC = 2-amino-1,4-benzenedicarboxylic acid, Br–H2BDC = 2,5-dibromo-1,4-benzenedicarboxylic acid) have been controllably synthesized with H2MDP and different aromatic dicarboxylic acids by tuning metal-to-ligand molar ratios, temperature, solvents and metal ions. Compound 1 is a 3D 2-fold interpenetrated pcu framework of 412·63 topology constructed from paddle-wheel SBUs and trans-conformation H2MDP pillars, while compound 2 exhibits a 3D 3-fold interpenetrated diamondoid framework formed by single metal nodes via linear NDC2− and trans-conformation H2MDP ligands. Interestingly, compound 3 contains two different types of binuclear subunits formed by a pair of Cd(II) ions with partly deprotonated HNDC− ligands, and these subunits are further linked by completely deprotonated NDC2− and cis-conformation H2MDP ligands to form a 2D (4,4) network. Compounds 4 and 5 are solvent-induced structural isomers based on 2D (4,4) layers, and therefore have different solvent-accessible voids. Compounds 6 and 7, synthesized with different metal salts under similar solvothermal conditions, are characteristic of a 3D hydrogen-bonded supramolecular network, and a 3D 3-fold interpenetrated diamondoid network with equal number of left- and right-handed helical {Cd(H2MDP)}n chains further bridged together by linear Br–BDC2− ligands, respectively. In addition, the luminescent properties of solids 1–6 have been investigated at room temperature.

Hydrothermal synthesis of two new zinc coordination polymers with mixed ligands

Abstract The hydrothermal reactions of zinc acetate with 1,2,4,5-benzenetetracarboxylic anhydride (btc) and 4,4′-bipyridine (4,4′-bpy) for [Zn2(4,4′-bpy)(btc)(H2O)2]n·2nH2O (1) or imidazole (imi) for [Zn2(imi)4(btc)(H2O)2]n (2) in the molar ratio of 1:1:1:2000 at 170 °C for five days led to the formation of colorless crystals of 1 and 2. The btc ligand acts as a four-dentate bridging ligand in both compounds to link up zinc atoms into linear chain architectures. In 1, the linear chain subpolymers are further interlinked into a lamellar framework via 4,4′-bpy ligands. Finally, both 1 and 2 are extended into three-dimensional framework via hydrogen bonding.