Two-dimensional Zn Research Articles

Fabrication of epoxy composite coating with superior anticorrosive properties using a pH-responsive system based on 2D Zn-MOF nanosheets

Herein, two-dimensional Zn(Bim)(OAc) nanosheets (ZNS) were prepared using ultrasonication and surfactant-assisted methods. Subsequently, it was used as nanocontainer loaded with benzotriazole (BTA) corrosion inhibitor to fabricate BTA@ZNS nanocomposites with pH-controlled release characteristics. The morphology analysis exhibits that BTA@ZNS has a distinct lamellar structure. UV spectrophotometer measurements indicated the release rate of BTA reached 94.38 % in 24 h at pH=1. Adding BTA@ZNS as fillers into epoxy resin (EP) coating can form BTA@ZNS/EP composite coating with active anti-corrosion properties. Electrochemical impedance spectroscopy (EIS) demonstrates that BTA@ZNS/EP coating has superior corrosion resistance than other EP-based coatings. The enhanced anti-corrosion performance is ascribed to the barrier effect and acid-responsive controlled release of BTA@ZNS.

A multifunctional sensor for detecting tetracycline, 4-nitrophenol, and pesticides

In recent years, due to the abuse of antibiotics, nitro explosives and pesticides, which have caused great harm to the environment and human health, social concerns have prompted researchers to develop more sensitive detection platforms for these pollutants. In this paper, a novel two-dimensional Zn (II) coordination polymer, [Zn(L)0.5(1,2-bimb)]·DMF (1), [H4L=[1,1′:4′,1′’-terphenyl]-2, 2′’,4, 4′’ −tetracarboxylic acid, 1,2-bimb = 1,2-bis(imidazol-1-ylmethyl)benzene] was synthesized using a hydro-solvothermal method. Among commonly used organic solvents, 1 exhibits significant stability. Fast and efficient fluorescence response can be achieved for tetracycline (TET), 4-nitrophenol (4-NP), fluazinam (FLU), and abamectin benzoate (AMB) with low detection limits. A binary intelligent logic gate device with FLU and AMB as chemical input signals is successfully constructed, which provides a new idea for biochemical detection. In addition, a portable visual test paper has been prepared, which has high sensitivity, good selectivity, and simple operation. It can be used for rapid detection of pollutants in daily life and has broad application prospects. Finally, a detailed discussion was conducted on the fluorescence sensing mechanism of 1 for detecting TET, 4-NP, AMB and FLU.

Two photochromic two-dimensional Zn(II)-MOFs based on a carboxybenzyl viologen ligand

Two new Zn(II) metal-organic frameworks (MOFs) {[Zn(Bpybc)0.5 (m-BDC)(H2O)]·2H2O}n (1) and {[Zn(H2Bpybc)(BTEC)(H2O)2]·H2O}n (2) have been successfully synthesized, where 1,1′-bis(4-carboxybenzyl)-4,4′-bipyridinium dichloride (H2BpybcCl2) is used to react as the predesigned ligand with two kinds of aromatic carboxylic acids (1,3-benzenedicarboxylic acid = m-H2BDC, 1,2,4,5-benzenetetracarboxylic acid = H4BTEC) as the secondary building linkers. Both two compounds own two-dimensional (2D) layered structures. In addition, compounds 1 and 2 display reversible photochromism, which is associated with the generation of free radicals via photoinduced electron transfer. Simultaneously, the photomodulated fluorescent properties and their potential applications in ink-less and erasable printing were also studied.

A water-stable two-dimensional Zn(BDC) lamellar membranes for efficient molecular separation with enhanced water permeability

Although 2D Zn(BDC) MOFs exhibit exceptional water stability, the synthesis of ultrathin 2D Zn(BDC) nanosheets has proven to be a formidable challenge. Conventional bottom-up methods suffer from limitations such as low yield and difficulties in eliminating surfactant molecules or end ligands, which are introduced to control the directional growth of 2D Zn(BDC). In this work, 2D Zn(BDC) nanosheets featuring a two-nuclear paddlewheel zinc structure were successfully synthesized through a three-phase synthesis method, exhibiting a thickness of about 2 nm. The 2D Zn(BDC) lamellar membranes were prepared through simple vacuum filtration. By adjusting the colloidal concentration of the 2D Zn(BDC) nanosheets, fine control over the resulting membrane thickness was achieved. Moreover, the incorporation of polyvinyl alcohol (PVA) as a cross-linking agent significantly enhanced the stability of the 2D Zn(BDC) lamellar membranes. The addition of PVA demonstrated effective regulation of pore size in the membrane, facilitating well-ordered stacking of nanosheets for superior screening efficiency in dye/ion separation applications. The permeability of 2D Zn(BDC) lamellar membranes was observed to be 372.9 L m−2 h−1 bar−1, while exhibiting a rejection rate exceeding 99.7 % for dye molecules, such as direct red (DR23), reactive black (RB5), chromium black T (CBT), Congo red (CR). The remarkable performance is ascribed to a synergistic effect between molecular sieving and electrostatic repulsion. 2D Zn(BDC) lamellar membranes exhibit exceptional long-term stability, and resistance to fouling and chlorine, thereby showcasing their immense potential for diverse applications in the realm of dye wastewater treatment.

Prediction and Characterization of Two-Dimensional Zn2VN3

A two-dimensional (2D) monolayer of a novel ternary nitride Zn2VN3 is computationally designed, and its dynamical and thermal stability is demonstrated. A synthesis strategy is proposed based on experimental works on production of ternary nitride thin films, calculations of formation and exfoliation energies, and ab initio molecular dynamics simulations. A comprehensive characterization of 2D Zn2VN3, including investigation of its optoelectronic and mechanical properties, is conducted. It is shown that 2D Zn2VN3 is a semiconductor with an indirect band gap of 2.75 eV and a high work function of 5.27 eV. Its light absorption covers visible and ultraviolet regions. The band gap of 2D Zn2VN3 is found to be well tunable by applied strain. At the same time 2D Zn2VN3 possesses high stability against mechanical loads, point defects, and environmental impacts. Considering the unique properties found for 2D Zn2VN3, it can be used for application in optoelectronic and straintronic nanodevices.

An ultra-sensitive dopamine photoelectrochemical sensing platform based on two-dimensional Zn carbon nanosheets, hollow Cu2O and CdTe QDs composite films

In this work, two-dimensional Zn carbon nanosheets (CNs) are obtained after heat treatment of in situ synthesized ZIF-8/NaCl nanocomposites, which are ultrasonically mixed with carboxylated multi-walled carbon nanotubes (MWCNTs). Subsequently, the nanocomposites Zn CNs-MWCNTs with large specific surface area and excellent catalytic properties are obtained. Meanwhile, the photoelectric material H–Cu2O/CdTe QDs are drop-coated on Zn CNs-MWCNTs/GCE and the modified electrode Zn CNs-MWCNTs/H–Cu2O/CdTe QDs/GCE is obtained. Eventually, a novel dopamine photoelectrochemical sensor based on Zn CNs-MWCNTs/H–Cu2O/CdTe QDs/GCE is constructed. Among them, the photocurrent intensity of H–Cu2O/CdTe QDs is much higher than that of pure H–Cu2O and pure CdTe QDs. This is due to the effective combination of CdTe QDs and H–Cu2O to form a p-p heterojunction, which can effectively suppress the recombination of electron-hole pairs. Subsequently, the working mechanism of the photoelectrochemical sensor is investigated in depth by the Kubelka-Munk model. At the same time, the photoelectrochemical sensor has reliable selectivity, stability, reproducibility and limit of detection (LOD = 0.3 nM), and also provides a new idea for the detection of dopamine.

High efficiency polymer solar cells sensitized by red-emitting ZnCuInS nanoplatelets

We synthesized the two-dimensional Zn–Cu–In–S (ZCIS) semiconductor nanoplatelets and then modified their surface with 4-bromobenzenediazonium tetrafluoroborate. The surface modified ZCIS nanoplatelets were combined with the conventional photovoltaic hole transport layer material (HTL) PEDOT: PSS. The work function of the HTL increased from 5.04 eV to 5.17 eV, thus promoting the reduction of the energy potential barrier and increasing the internal electric field. It also effectively improves the light utilization by effectively increasing the absorption of light in the spectral range below 500 nm and converting them into the secondary emission in the 600–700 nm range. Such emission can be effectively utilized by the active layer to increase the open-circuit voltage (Voc) and short-circuit current (Jsc) of the cell, resulting in an increase in the overall cell power conversion efficiency (PCE) from 12.29%–13.14%.

Two-Dimensional Layered Zn(II) Metal–Organic Framework as Photocatalyst for Lupus Nephritis Therapy

A new Zn(II) metal–organic framework formulated as [Zn3.5(SO4)2(μ3-OH)2(1,2,3-tz)(H2O)2]n (1, 1,2,3-Htz = 1,2,3-triazole) was subjected to solvothermal integration and structural modification. Semiconductive property was confirmed by UV-Vis diffuse spectrum, which showed an optical band gap of 2.68 eV. The solid specimen of 1 used as a photocatalyst exhibited outstanding photocatalytic performance with regard to MV degradation in aqueous solution during UV light illumination. The potential of the photocatalyst for lupus nephritis therapy and the underlying mechanism were investigated. ELISA revealed that FcyR II accumulated in plasma. The percentage of apoptotic renal epithelial cells was also measured with flow cytometry.

One-pot synthesis of 3D-ZIF-7 supported on 2D-Zn–Benzimidazole–Acetate and its catalytic activity in the methoxycarbonylation of aniline with dimethyl carbonate

For the first time, three-dimensional Zeolitic Imidazole Framework (3D) ZIF-7 (Zn(BeIM)2, BeIM=benzimidazole) supported on two-dimensional (2D) Zn(BeIM)OAc (Zinc–Benzimidazole–Acetate) was synthesized by reacting Zn(OAc)2 and benzimidazole in a one-pot reaction. By modulating the amount of diethylamine during the reaction, the ZIF-7/Zn(BeIM)OAc with a 1 to 1 molar ratio was obtained when the reactant molar ratio of Zn(OAc)2 and benzimidazole was 1 to 1.5. It was found that 3D-ZIF-7 was synthesized first and then transformed into 2D-Zn(BeIM)OAc by the reaction with remaining Zn(OAc)2.The synthesized ZIF-7 (Zn(BeIM)2) supported on Zn(BeIM)OAc (1/1) showed enhanced catalytic performance in the methoxycarbonylation of aniline with dimethyl carbonate. The yield of methyl N-phenyl carbamate reached 92.0% in 2h at 190°C, which was higher than yields obtained using the single component catalysts ZIF-7 (69.9%) and Zn(BeIM)OAc (35.4%). Furthermore, this catalyst was successfully reused four times, maintaining an MPC yield of 92.0%–95.8%.

A mixed-ligand Zn(II)-coordination polymer: selective detection of Fe3+ ion and promotion activity on the flap transplantation via increasing the vascular endothelial cells proliferation

In the current study, on the basis of 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector, a novel two-dimensional luminescent Zn(II)-coordination polymer whose chemical formula is {[Zn5(timb)4(OH–IPA)4]·2NO3·2DMA·2H2O}n was generated through the reaction between timb and Zn(NO3)2·6H2O in the presence of the OH functionalized isophthalic acid ligand (OH-H2IPA). Furthermore, for the Fe3+ ion, complex 1 reflects superb luminescence sensing performances in the water solution with high selectivity and high sensitivity. The assessment of its promotion activity on the flap transplantation was implemented. Meanwhile, its detailed mechanism was also studied. First of all, the detection of the proliferation activity levels on vascular endothelial cells was conducted with the Cell Counting Kit-8. Subsequently, the signaling pathway of HIPPO activation level was further detected in the vascular endothelial cells after compound treatment.

The use of C1 symmetry imidazole-carboxylate building block and auxiliary acetate co-ligand for assembly of a 2D wave-like zinc(II) coordination polymer: experimental and theoretical study

We report the synthesis and characterization of a two-dimensional Zn(II) coordination polymer employing a ligand with a biphenyl core containing imidazole and carboxylate groups in the presence of acetate moieties as bridging molecules. The obtained [ZnLAc]n was structurally characterized via X-ray, FTIR, TGA, PXRD, SEM and EDX analyses. Computer-aided calculations based on density functional theory (DFT) were employed to assess the optimal conformational geometries of both the starting ligand and the Zn(II) complex. Computational results were compared with the experimental data, disclosing a reasonable agreement. Comparisons between the single-crystal structures and the calculated optimized geometries of the molecular entities are discussed. In addition, the time-dependent DFT method (TD-DFT) was applied to assess the first excited state of the ligand and complex.

Synthese, structure and photocatalytic properties of a new two-dimensional polymer based on 4,4′-bis(2-methylimidazol-1-yl)diphenyl ether and 5-tert-butyl isophthalic acid

A two-dimensional Zn(II) complex {[Zn(BMIOPE)(TBIP)]·H2O} n (1) (BMIOPE = 4,4′-bis(2-methylimidazol-1-yl)diphenyl ether, H2TBIP = 5-tert-butyl isophthalic acid) has been synthesized and characterized using single crystal X-ray diffraction, IR and elemental analysis. Single-crystal X-ray diffraction analysis reveals that complex 1 is a two-dimensional (4, 4) layer. The thermal stability, solid-state photoluminescence properties and photocatalytic properties of complex 1 have been investigated.

Two Novel 2D Zn (II) Coordination Polymers with Quinoline-3-Carboxylic Acid and Tetraphenylphthalic Acid: Synthesis and Photoluminescence Properties

Two novel two-dimensional (2D) Zn coordination polymers,namely [Zn(qnl)2]n (Zn-qnl) and [Zn2(tpp)(OH)2(H2O)]n (Zn-tpp) (qnl = quinoline-3-carboxylate anion, tpp = tetraphenyl phthalate anion) have been hydrothermally synthesized and discussed their solid state photoluminescent properties. Two novel Zn coordination polymers with ligands quinoline-3-carboxylic acid (Hqnl) and tetraphenylphthalic acid (H2tpp) have been prepared and characterized by X-ray crystallography. Zn-tpp and Zn-qnl show a 2D hinge layer and a 2D layer with quadrilateral meshes, respectively.

Crystal Structure And Luminescent Property of a New Two-Dimensional Polymer Based on 1,4-Bis(4-(Imidazole-1-yl)Benzyl)Piperazine

A two-dimensional Zn(II) complex [Zn(BIBP)(TBIP)]n (1) (BIBP = 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine, H2TBIP = 5-tert-butyl isophthalic acid) is synthesized and characterized using single crystal X-ray diffraction, IR spectroscopy, and elemental analysis. The single crystal X-ray diffraction analysis reveals that complex 1 is an achiral two-dimensional layer based on 1D left- and right-handed helical [Zn(BIBP)] 2 chains, which are linked by C—H⋯O hydrogen bonds to form a three-dimensional supramolecular framework. Moreover, complex 1 exhibits an emission band at 393 nm (λex = 244 nm).

A new two-dimensional ZnII coordination polymer based on 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and 5-nitrobenzene-1,3-dicarboxylic acid: synthesis, crystal structure and physical properties

A novel two-dimensional (2D) ZnII coordination framework, poly[[μ-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene](μ-5-nitrobenzene-1,3-dicarboxylato)zinc(II)], [Zn(C8H3NO6)(C14H14N4)]n or [Zn(NO2-BDC)(1,3-BMIB)]n [1,3-BMIB is 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and NO2-H2BDC is 5-nitrobenzene-1,3-dicarboxylic acid], has been prepared and characterized by IR, elemental analysis, thermal analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that the compound is a new 2D polymer with a 63 topology parallel to the (10-2) crystal planes based on left-handed helices, right-handed helical NO2-BDC-Zn chains and [Zn2(1,3-BMIB)2]n clusters. In the crystal, adjacent layers are further connected by C-H...O hydrogen bonds, C-H...π interactions, C-O...π interactions and N-O...π interactions to form a three-dimensional structure in the solid state. In addition, the compound exhibits strong fluorescence emissions in the solid state at room temperature.

Effects of substituent groups on the crystal structures and luminescence properties of zero-/two-dimensional Zn(II) complexes

The 3-position substituted imidazo[1,2-a]pyridine ligands L1 and HL2 were facilely synthesized, and used for construction of two novel luminescent Zn(II) complexes, namely [ZnCl2(L1)2] (1) and [Zn(L2)2]n (2). Single-crystal X-ray diffraction analysis shows that 1 is zero-dimensional structure, whereas, 2 possesses two-dimensional polymeric network with rhombic grid motifs. The structural differences between 1 and 2 should be determined by the different substituent groups adjacent to carbonyl groups of the 3-position substituted imidazo[1,2-a]pyridine ligands. Complex 1 reveals the red-shifted emission band, compared to free L1 ligand, whereas, 2 displays similar emission spectrum to free HL2 ligand. Such results are also ascribed to substituent group effects and corresponding structural differences.

Crystal structure and luminescent property of a new two-dimensional polymer based on 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine

A two-dimensional Zn(II) complex [Zn(BIBP)(TBIP)]n (1) (BIBP = 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine, H2TBIP = 5-tert-butyl isophthalic acid) is synthesized and characterized using single crystal X-ray diffraction, IR spectroscopy, and elemental analysis. The single crystal X-ray diffraction analysis reveals that complex 1 is an achiral two-dimensional layer based on 1D left- and right-handed helical [Zn(BIBP)]n2+ chains, which are linked by C—H⋯O hydrogen bonds to form a three-dimensional supramolecular framework. Moreover, complex 1 exhibits an emission band at 393 nm (λex = 244 nm).

Temperature-dependent ultraviolet photoluminescence in hierarchical Zn, ZnO and ZnO/Zn nanostructures.

The temperature-dependent effects on the ultraviolet (UV) photoluminescence (PL) enhancement, blueshift, thermal quenching, and chromaticity of the two-dimensional (2D) Zn nanosheets, 2D-hierarchical ZnO nanostructures, and 2D-hierarchical ZnO/Zn nanostructures are presented. In this study, 2D Zn nanosheets were synthesized using a hot-plate metal vapor deposition technique, after which 2D-hierarchical ZnO nanostructures and ZnO/Zn were prepared from the 2D Zn nanosheets by a simple thermal annealing method. The enhancement and blueshift of the UV PL emissions from the three nanostructures at low temperatures arose from three distinct PL mechanisms. For the ZnO nanostructures, the UV PL emission enhancements and blueshifts at low temperature were due to the conversion of the free excitons (FXs) to neutral-donor-bound-excitons (D0Xs). The ZnO/Zn nanostructures possessed the highest UV PL intensities among the three nanostructures, because the free electrons from the Zn portions across the metal-semiconductor heterojunctions greatly assisted in enhancing the PL emissions. The enhancement and thermal quenching were quantitatively analyzed with simple normalization methods. The results show that all three kinds of nanostructures are excellent candidates for use in UV light emitters.

Construction of one new two-dimensional Zn(II) coordination polymer based on thiophene-2,5-dicarboxylate and bis(imidazole) mixed ligand

ABSTRACTUnder hydrothermal conditions, a new two-dimensional (2D) zinc coordination polymer, [Zn(tdc)(bimm)]n, was synthesized based on thiophene-2,5-dicarboxylic acid (H2tdc) and 1,2-bis(imidazol-1′-yl)methane (bimm) mixed ligands. Single crystal X-ray structural analysis shows adjacent Zn2+ ions are connected by tdc2− anions to form a one-dimensional (1D) [ZnL]n chain in the complex. Then flexible bimm ligands expand 1D chains into a 2D layer by linking neighboring Zn2+ ions. These adjacent layers are further stacked together by direct C−H···π supramolecular interactions, generating a double-layer 2D supramolecular structure. In topology, the 2D lay could be rationalized to a uninodal 4-connected non-interpenetrated sql net with {44.62} topology. In addition, solid state properties such as thermogravimetric analysis and luminescence were also investigated.

Assembly of highly efficient photocatalytic CO2 conversion systems with ultrathin two-dimensional metal–organic framework nanosheets

An ultrathin two-dimensional Zn porphyrin-based metal–organic framework (Zn-MOF nanosheets) is developed and used for the first time in photoreduction of CO2 to CO. Consequently, two novelty noble-metal-free hybrid photocatalytic systems are established and displayed outstanding photocatalytic activity and selectivity for CO evolution under mild photocatalytic reaction conditions. The insight revealed Zn-MOF nanosheets as photosensitizer displays a better charge transport ability and longer lifetime of the photogenerated electron-hole pairs than the Zn-MOF bulk, which are confirmed by photoelectrochemical impedance and photoluminescence (PL) measurements. These studies show that the development of noble-metal-free photocatalytic systems and various MOF-based materials for photocatalytic applications are promising.