Literature Review of the Use of Zinc and Zinc Compounds in Paper-Based Microfluidic Devices

Zinc and its compounds, alloys and composites play an important role in the modern day world and find application in almost every aspect that can improve the quality of our lives. This ranges from supplements and pharmaceuticals that are meant to improve our health and wellbeing to additives meant to guard or reduce corrosion in metals. However, over the past several years, a new area of technology has been garnering a great deal of attention and has made use of zinc and its compounds. This is with reference to paper-based microfluidic technology that offers several advantages and that keeps expanding in the amount of applications it covers. In this paper, a review is offered for the applications that have used zinc or zinc compounds in paper-based microfluidic devices.

Two Novel Zinc Compounds with in situ Formation of Dimethylamine Ligand

The investigation of the supramolecular interactions between the zinc chloride salts and the crown ether in tetrahydrofuran （THF） with the diffusion of in situ formed DMA （DMA = dimethylamine） ligand leads to two novel zinc-DMA compounds, [（H3O）·（18C-6）][ZnCl3（DMA）] 1 and [（HDMA）·（18C-6）][ZnCl3（DMA）] 2 （18C-6 = 18-crown-6）, whose emissions fall into the blue-emission field. Crystal data for compound 1： monoclinic, space group P21/c, a = 8.753（1）, b = 14.538（2）, c = 19.969（3）A, β = 110.121（7）°, V = 2386.2（5）A^3, T = 293（2） K, Z = 4, Mr = 500.14, Dc= 1.392 g/cm^3,μ = 1.395 mm^-1, F（000） = 1048, S = 1.006, R = 0.0611 and wR = 0.1755 for 3676 observed reflections with I 〉 2σ（I） and 235 parameters. For 2： triclinic, space group P1^-, a = 9.2672（4）, b = 11.8778（2）, c = 13.3846（1） A, a = 67.09（1）, β = 75.54（2）, ）,γ = 81.32（2）°, V = 1311.74（6） A^3, T = 293（2） K, Z = 2, Mr = 527.21, Dc = 1.335 g/cm^3,μ = 1.271 mm^-1, F（000） = 556, S = 1.006, R = 0.0393 and wR = 0.1034 for 3839 observed reflections with I〉 2σ（I）.

High Quality Zinc Sulfide Epitaxial Layers Grown by Metalorganic Chemical Vapour Deposition

ZnS films were successfully grown by metallorganic chemical vapour deposition (MOCVD) at atmospheric pressure on (100) GaAs substrates. The deposition was carried out at a substrate temperature between 280 approximately 550°C with optimisation of reactor design and growth conditions. The gas phase prereaction is effectively restrained. These epilayers exhibit high crystallographic quality and reveal a mirror surface morphology. The peak halfwidths of X-ray diffraction patterns from their (400) faces are within 0.06 approximately 0.09°. The epilayers grown on (111) GaAs, (112ˉ0) Al2O3 and (100) Si have proven to be single crystalline feature. The optical and electrical characteristics of ZnS epilayers are measured by photoluminescence, cathodeluminescence, and the Van der Pauw method. The results indicate that there are not a large number of deep centers that could be detected both at 77K and at room temperature. A broad CL peak around 2.897eV and 2.672eV was observed only under very strong excitation. Their origin has not been examined. All epilayers present high resistivities up to 1013Ω&middotcm.

Construction of a New(4,8)-Connected Coordination Polymer Based on the Zinc Cluster:Structure,Topology,and Luminescence

The title complex, [Zn3（L）2（H2 O）2]n（1, H3 L = 5-（（3-formylphenoxy）methyl）isophthalic acid）, has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Compound 1 exhibits a 3D binodal（4,8）-connected net based on trinuclear [Zn3（COO）4] clusters with the topology symbol of（416·612）（44·62）2. It crystallizes in monoclinic system, space group P21/c, with a = 13.548（3）, b = 13.291（3）, c = 8.2750（1） ？, β = 97.08（3）°, V = 1478.7（6） ？3, Z = 2, Mr = 858.6 g/mol, Dc = 1.928 mg/m3, μ = 2.49 mm-1, F（000） = 864, GOOF = 1.12, the final R = 0.0457 and wR = 0.1329 for 4334 observed reflections with I 〉 2σ（I）. Additionally, the photoluminescent behaviours of 1 and H3 L have also been investigated in the solid state at room temperature.

A Novel Luminescent Zinc(Ⅱ) Coordination Polymer with 2D → 3D Polythreaded Motif

A new zinc（Ⅱ） compound, [Zn（BTA）（UCA）]n （1, HBTA = 1,2,3-benzotriazole, HUCA = 4-imidazoleacrylic acid）, has been synthesized via the hydrothermal reactions of Zn（OAC）2.2H20, HBTA and HUCA. The crystal structure is of monoclinic, space group P21/c with a = 7.450（3）, b = 18.911 （8）, c = 9.198（4） A, fl = 94.317（8）°, V = 1292.2（9） A3, C12HgNsO2Zn, Mr = 320.63, Z = 4, Dc = 1.648 g/cm3, F（000） = 648,/z = 1.909 mm-1, R= 0.0255 and wR= 0.0655 for 2104 observed reflections （I 〉 2a（/））. Single-crystal X-ray diffraction analysis revealed that compound 1 features a two-dimensional （2D） layered framework based on benzotriazole controlled dinuclear [Zn2（BTA）2] subunits. Furthermore, these 2D layers are threaded into a 3D supramolecular framework via the direction of intermolecular hydrogen bonds and π-π interactions. In addition, the thermal stability and fluorescence property of compound 1 were also investigated.

Crystal Structures,Luminescent Properties and Hirshfeld Surface Analyses of Zn(Ⅱ)and Cd(Ⅱ)Compounds Based on 1-(2-Carboxyl-phenyl)-3-(pyridin-2-yl)pyrazole

Two compounds,[Zn2（Hcppp）2（cppp）2（H2O）2]·2 NO3·6 H2O（1） and [Cd（Hcppp）2Cl2]· 3H2O（2）（Hcppp = 1-（2-carboxyl-phenyl）-3-（pyridin-2-yl）pyrazole）,are synthesized and characterized by IR,TGA and X-ray single-crystal/powder diffraction.Compound 1 crystallizes in monoclinic system,space group P21/c with a = 9.894（2）,b = 15.856（3）,c = 20.430（4） A,β = 101.70（3）°,V = 3138.5（11） A3,Z = 2,Mr = 1457.94,Dc = 1.543 g/cm^3,F（000） = 1504,R = 0.0278 and wR = 0.0749 for 6157 observed reflections（I 〉 2σ（I））.Compound 2 crystallizes in triclinic system,space group P1 with a = 9.1424（4）,b = 11.6427（5）,c = 16.1345（7） A,α = 102.6430（10）°,β = 95.4530（10）°,γ = 104.0060（10）°,V = 1605.94（12） A3,Z = 2,Mr = 767.88,Dc = 1.588 g/cm^3,F（000） = 776,R = 0.0307 and wR = 0.0764 for 6275 observed reflections（I 〉 2σ（I））.Compound 1 exhibits a binuclear structure while compound 2 shows a mononuclear structure.In compound 1,two cppp-ligands display the μ2-kN,N′：k O and two Hcppp ligands show the μ1-kN,N′ coordination modes.However,two Hcppp ligands connect one Cd（Ⅱ） cation and exhibit the μ1-kN,N′ binding mode in compound 2.The compounds are both studied using Hirshfeld surface analyses and 2D fingerprint plots.The luminescent properties are also discussed.

Construction and Photoluminescence Properties of Zn(Ⅱ)/Cd(Ⅱ) Complexes with 4-Amino-3,5-propyl-1,2,4-triazole Ligand

Reaction of ZnCI2 and 4-amino-3,5-propyl-1,2,4-triazole （dpatrz） or CdC12, NaN3 and dpatrz, in aqueous solution at room temperature yields two neutral clusters： a dinuclear complex [Zn2（dpatrz）2Ch] （I） and a linear trinuclear complex, [Cd3（dpatrz）4（N3）2Cl4] （II）. Both complexes have been characterized by X-ray single-crystal diffraction, powder XRD, IR, elemental analysis, TG and fluorescence analysis. Complex I crystallizes in orthorhombic, space group Pbca with a = 11.865（2）, b = 14.464（3）, c = 15.985（3） A, V= 2743.4（9） A3, Z = 4, C16H32NsCI4Zn2, Mr = 609.4, Dc = 1.475 g.cm3, p = 2.16 mm-1, F（000） = 1248, GOOF = 1.091, the final R = 0.0295 and wR = 0.0665 for 1999 observed reflections （I 〉 2a（/））. Complex Ⅱcrystallizes in monoclinic, space group P2/c with a = 11.408（2）, b = 15.211（3）, c = 18.152（6） A, fl = 123.75（2）°, V = 2619.1（1） A3, Z = 2, C32H64N22ClaCd3, Mr = 1236.05, Dc = 1.567 g.cm3, p = 1.46 mm-1, F（000） = 1244, GOOF = 1.042, the final R = 0.0444 and wR = 0.0913 for 3466 observed reflections （I 〉 2a（/））. The analysis of X-ray revealed that both structures lie about the inversion centers： complex I adopts two pl,2-triazole bridges linking two Zn（II） ions and II forms a linear trinuclear structure with four μ1,2-triazoles and two/μIA-N3 bridging modes. There are different coordinated geometries for three Cd（II） ions in Ⅱ： one is coordinated with an octahedral environment, and the other two are distorted tetragonal pyramids （r = 0.34）. The hydrogen bonds of C-H...C1 and N-H...C1 lead to the discretes into a 3D supramolecular network in both compounds. The thermal stabilities and photoluminescence behaviors of them were also studied.

Organic Carboxylate Ligand Tuned Topological Variations in Three Zn(Ⅱ)Coordination Polymers:Syntheses,Crystal Structures and Photoluminescent Properties

Three new Zn（Ⅱ） coordination polymers, namely [Zn2（suc）2（bib）2]n·nH2 O（1）, [Zn（glu）（bib）]n·4 nH2 O（2）, and [Zn（adp）（bib）]n（3）（bib = 1,4-bis（N-imidazolyl）butane, H2 suc = succinic acid, H2 glu = glutaric acid, H2 adp = adipic acid） have been hydrothermally synthesized and structurally characterized. Compound 1 features a 3D framework with 4-connected hxg-d topological network, compound 2 is comprised of 2D 44-sql-type sheets, and the adjacent 2D sheets are further packed into a 3D supramolecular architecture via intermolecular hydrogenbonding interactions, and compound 3 is a 3D framework with 4-fold interpenetrating dia topology. The structural comparison of these three compounds demonstrates that the topological variations can be well controlled by employing aliphatic dicarboxylate ligands with different spacer lengths. Moreover, the thermal stabilities and photoluminescent properties of them were also studied in detail.

Synthesis and Crystal Structure of a New Zn(Ⅱ) Coordination Polymer Constructed by 1,2,4,5-Benzenetetracarboxylate

A new Zn（Ⅱ） coordination polymer [Zn3（btec）（OH）2（H2O）2]n （1, btec = 1,2,4,5- benzenetetracarboxylate） has been synthesized by hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in mono- clinic, space group C2/c, with a = 19.580（3）, b = 5.0137（8）, c = 15.975（3）, β = 121.629（2）°, V = 1335.3（4）3, C10H8O12Zn3, Mr = 516.27, Z = 4, Dc = 2.568g/cm3, μ = 5.419 mm-1, F（000） = 1016, R = 0.0590 and Rw = 0.1279 for 1110 observed reflections （I 2σ（I））. X-ray analysis shows that the asymmetric unit of the title compound contains two crystallographically unique Zn（Ⅱ） atoms which are connected through the bridging carboxylate oxygen atoms of the btec ligands and μ2-bridging oxygen atoms of water molecules to generate an infinite one-dimensional chain. The adjacent chains are linked together through the benzene rings of the btec ligands to form a two-dimensional polymeric network. The adjacent two-dimensional layers are further connected together by the benzene rings of btec ligands to give the final three-dimensional structure. The benzene rings act as pillars between two layers.

Synthesis, Crystal Structure, Luminescence Property and DFT Calculations of a New Coordination Compound Containing 8-Aminoquinoline Ligand

A new luminescent compound, Zn（8-aminoql）2（SCN）2 （1, 8-aminoql = 8-amino quinoline）, has been synthesized and its structure was characterized by IR, elemental analysis and X-ray single-crystal diffraction. Compound 1 belongs to the orthorhombic system, space group Pbca with a = 8.503（2）, b = 14.427（4）, c = 31.922（8）A, V= 3916.0（18） A3, Z = 8, C20H16N6S2Zn, Mr = 469.88, Dc = 1.594 Mg/m3, μ = 1.488 mm-1, F（000） = 1920, T = 296（2） K, the final R = 0.0293 and wR = 0.0645 for all 2763 observed reflections （1 〉 2a（/））. Compound 1 displays a 3D supramolecular architecture formed by N-H--S hydrogen bonds and π...π aromatic packing interactions. Photoluminescence studies reveal that it displays obvious fluorescent emission band （λex = 320 nm） at 533 nm in the solid state at room temperature. The emission bands possess a broad asymmetric feature, which can be assigned to ligand-to-ligand charge transfer transitions based on DFT calculations.

Three Novel Luminescent Zinc(Ⅱ)Compounds Constructed by Employing Mixed-ligand Strategy

Three novel coordination polymers,[Zn(suc)(o-bix)]_(n)(1),[Zn(suc)(m-bix)·H_(2)O]_(n)(2)and[Zn_(2)(suc)_(2)(p-bix)_(2)·4H_(2)O]_(n)(3)(H_(2)suc=succinic acid,o-bix=1,2-bis(imidazol-1-ylmethyl)-benzene,m-bix=1,3-bis(imidazol-1-ylmethyl)-benzene,p-bix=1,4-bis(imidazol-1-ylmethyl)-benzene),have been synthesized and structurally characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis,powder X-ray diffraction,and single-crystal X-ray diffraction.These three coordination polymers present various structures originated from auxiliary N-donor ligands with different configurations.Compound 1 shows a 2D network with 4^(4)-sql topology.Compound 2 exhibits an infinite chain,and the adjacent chains are extended into a 2D sheet by π-πstacking interactions.Changing the conformation of the N-donor ligand leads to 3 featuring a 3D framework with a novel 4-connected(6^(5)·8)topology.In addition,the solid-state photoluminescent properties of compounds 1~3 are investigated.

Dissolution of different zinc salts and Zn uptake by Sedum alfredii and maize in mono-and co-cropping under hydroponic culture

Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono-and co-cropped （without a root barrier） in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3（PO4）2 and 5ZnO·2CO3·4H2O （represented as ZnCO3 ） at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order： ZnCO3 〉 ZnO 〉Zn3（PO4）2 〉 ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2＋ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids （LMWOA） and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

Dielectrophoretic assembly of ZnO nanowires

The synthesis of zinc oxide （ZnO） nanowires is achieved by vapor phase transportation （VPT） method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of ZnO nanowires. Dielectrophoresis （DEP） method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution. Under the dielectrophoretic force, the nanowires are trapped on the pre-patterned electrodes, and further aligned along the electric field and bridge the electrode gap. The dependence of the alignment yield on the applied voltage and frequency is investigated.

Third-order optical nonlinearities of Zn_(1-x)Mg_xO thin films

The Zn1-xMgxO thin films were deposited on sapphire substrates by reactive electron beam evaporation deposition （REBED）. The X-ray diffraction （XRD） measurement demonstrates that these films undergo phase transition from hexagonal to cubic with increasing the Mg concentration. Absorption coefficients at 532 nm of the samples were obtained from the absorption spectra. Using optical Kerr effect, the thirdorder susceptibilities of the ternary films over a wide range of Mg concentrations were determined. The magnitude of X^（3） of the ternary Zn1-xMgxO films is order of 10^-11 esu at λ = 532 nm. The sample with phase mixture of both hexagonal and cubic structures shows the largest third-order susceptibility. The difference observed in the magnitude of X^（3） of Zn1-xMgxO films is attributed to the different microstructures of the ternary films, such as crystalline phase separation and crystal grains that enhance stimulated scattering.

ZnCl_2-assisted Synthesis of ZnSe Polycrystal

A chemical-assisted element direct-reaction method is developed to synthesize ZnSe compound semiconductor material at a relatively low temperature （-1000 ℃）. ZnSe polycrystal was obtained in the closed-tube systems with Zn-Se, Zn-Se-Zn（NHa）2CI2, ZnoSe-NH4CI and Zn-Se-ZnCI2. The as-synthesized samples were tested by X-ray diffraction （XRD）, thermogravimetric analysis （TGA） and analyzed by thermodynamic numerical method. The results demonstrate that the synthesis efficiency is higher than 99.96% for Zn-Se-ZnCl2 system at around 1000 ℃ for 3 weeks. It also exhibits that not only temperature, but also low apparent ratio of volume and surface area of the source materials and higher ZnCl2 content are required to achieve high synthesis efficiency. A SeCI transporting reaction synthesis process is proposed based on the thermodynamic analysis.