Bifunctional Zn Research Articles

A bifunctional Zn(II) coordination polymer for fluorescence recognition towards hazardous matters and its high adsorption removal of dye pollutant

In this work, a novel Zn(II) coordination polymer (denoted as Zn-CP) was constructed by the mixed ligands of 6-(3′,4′-Dicarboxy phenoxy)isophthalic acid (H4L) and 4,4′-bis(imidazolyl)biphenyl (bib) under solvothermal method. And based on the Zn-CP, the surfactant agent sodium dodecyl sulfate (SDS) was further introduced into the structure, thus obtaining the Zn-CP(S) which possessed the same phase but a smaller size compared with the Zn-CP. Interestingly, the Zn-CP(S) presented a significantly ameliorated fluorescent intensity, about 4.36 times higher than that of the Zn-CP prepared in the absence of SDS. Taking advantage of the improved fluorescence trait of the Zn-CP(S), a fluorescence recognition towards hazardous matters was further carried out. The results showed that Zn-CP(S) could simultaneously recognized for Hg2+, Cr2O72− and a broad range of hazard nitroaromatic explosives with the satisfactory limits of detection (LODs). In addition, Zn-CP could also be used as a recyclable adsorbent to remove methyl orange (MO) in aqueous medium. The maximum equilibrium adsorption capacity of Zn-CP for MO was 61.01 mg/g, and the adsorption mechanism could be attributed to the weak inter-molecular interaction involved π-π stacking and hydrogen bonding between Zn-CP and the MO molecule. Therefore, the bifunctional material has potential application prospects in fluorescence recognition and adsorption.

Redistributing Zn ion flux by bifunctional graphitic carbon nitride nanosheets for dendrite-free zinc metal anodes

g-C3N4nanosheets are fabricated and assembled on glass fibre separators as bifunctional Zn ion distributors for dendrite-free Zn anodes, endowing the Zn//MnO2batteries with enhanced performance.

A water-stable 2D+2D→3D polycatenated coordination polymer for selective adsorption of methylene blue and detection of Fe3+ ion from aqueous solution

A bifunctional Zn(II)-coordination polymer, namely, {[Zn2(μ4-BDPT)(μ-dpetan)2]⋅2H2O}n (1) (BDPT: bis(3,5-dicarboxyphenyl)terephthalamide, dpetan: 1,2-bis(4-pyridylethane)) was synthesized under solvothermal condition and characterized. Single crystal X-ray result showed that compound 1 displayed a 2D+2D→3D inclined polycatenation and a 3,4-conntected mcm/Cairo tiling-type topology. The compound exhibited high stability in aqueous solution with three pH values (2, 7.32 and 10). Bifunctional compound 1 adsorbed methylene blue (MB) and detected Fe3+ ions in aqueous solution. The adsorption studies revealed that the compound removed selectively the MB with an excellent efficiency from dye mixture (MB-MO) and the removal efficiency and the maximum adsorption capacity for MB were calculated as 99.7% and 239.57 mg g−1, respectively, at pH = 10 and at room temperature. This selective adsorption could be assigned to the electrostatic interactions between cationic dye (MB) and nucleophilic groups on compound 1. Moreover, the luminescence studies showed that the compound exhibited highly selective and sensitive detection towards Fe3+ ions over the other competing metal ions with a detection limit of 2.1 × 10−4 M. The results indicated that 1 could be usable as a selective adsorbent for MB and a luminescent sensor for the detection of Fe3+ ions.

Construction of a bifunctional Zn(ii)–organic framework containing a basic amine functionality for selective capture and room temperature fixation of CO2

The construction of a novel 3D, porous, bifunctional Zn(ii)–organic framework featuring two-types of 1D channels for efficient fixation of CO2 to cyclic carbonates under solvent-free mild conditions of RT is reported.

Zn2+-Doped Carbon Dots, a Good Biocompatibility Nanomaterial Applied for Bio-Imaging and Inducing Osteoblastic Differentiation in vitro

Multifunctional photoluminescent (PL) nanomaterials have attracted considerable interest in terms of their potential applications in the field of clinical medicine. Carbon dots (CDs), as emerging optical nanomaterials, are promising in various fields including biological imaging, drug transport and nerve tracing. However, little research has investigated on bone tissue engineering as of now. In this study, a new kind of bifunctional Zn[Formula: see text]-doped carbon dots (Zn-CDs) has been synthesized by a one-step hydrothermal method, Zn-CDs show effective fluorescent imaging and induce osteoblastic differentiation abilities in vitro. Moreover, compared with the raw material, Zn-CDs exhibited more effective osteoblastic differentiation promoting capability. Overall, the biocompatible nanomaterial Zn-CDs show potential to be used as a promising novel nanodrug for bone loss therapy and also a monitor of cell variation by fluorescence imaging.

A bifunctional Zn(II)-MOF as recyclable luminescent sensor for detecting TNT and Fe3+ with high selectivity and sensitivity

A znic fluorescence framework {[(Zn2(BDPO)·3H2O]·H2O}n (1) (H4BDPO = N,N′-Bis(3,5-discarboxyphenyl)oxalamide) was successfully synthesized and characterized. Complex 1 is a 2D sheet [Zn2(BDPO)]n, the H-bondings and π···π interactions extend the 2D sheet into 3D supermolecular framework. Importantly, it is a rarely reported highly selective and sensitive luminescence MOF sensor for detecting 2,4,6-Trinitroluene(TNT) and Fe(III) simultaneously through fluorescence quenching. Furthermore, the sensing mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of 1 and analytes.

Preparation and characterization of bifunctional Zn doped TiO2 aerogels toward Rhodamine B in water

Morphology control, surface functionalization and doping are effective ways to improve photocatalytic performance. In this paper, bi-functional Zn doped TiO2 aerogels were obtained by sol–gel method combined with ambient pressure drying. The Zn dopant promoted the crystallization of anatase and rutile TiO2, a significant red shift of absorption edge and an increase of BET specific surface area. The adsorption and photocatalytic degradation experiments showed that the efficiency for Zn doped TiO2 aerogels were higher than that of pure TiO2 aerogel and P25 under visible light irradiation. This was mainly because the sub-bands in TiO2 caused by Zn dopant extended the light absorption range of TiO2. Rhodamine B (RhB) degradation was achieved through a synergistic mechanism of adsorption and photocatalysis. Zn doped TiO2 aerogels could be used as an effective and alternative materials for the treatment of water contaminated with organic pollutants.

Novel 3D Nitrogen-Rich Metal Organic Framework for Highly Efficient CO2 Adsorption and Catalytic Conversion to Cyclic Carbonates under Ambient Temperature

A novel Lewis acid–base bifunctional Zn(II)-based MOF-Zn-1 [Zn2L2MA·2DMF] (MA = melamine, H2L = 2,5-thiophenedicarboxylic acid), with abundant micropores and free -NH2 groups was facilely assembled...

Mechanistic Insights into One-Step Catalytic Conversion of Ethanol to Butadiene over Bifunctional Zn–Y/Beta Zeolite

Bifunctional Zn–Y/Beta catalyst was applied in the reaction mechanism study of the ethanol to butadiene conversion to clarify the roles of Zn and Y functional sites in each individual reaction step. According to the results of several complementary methods, i.e., ethanol temperature-programmed desorption (TPD), temperature-programmed surface reaction (TPSR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), the reaction network consisting of several key steps, i.e., ethanol dehydrogenation, acetaldehyde aldol condensation, and crotonaldehyde reduction, was elucidated. An enolization mechanism was verified to involve in the coupling step. During this reaction, the Lewis acidic Zn and Y species in [Si]Beta zeolite were both active in the ethanol dehydrogenation, aldol condensation, and Meerwein–Ponndorf–Verley reduction. In this cycle, Zn species exhibited the higher dehydrogenation activity but lower coupling activity than that of Y species. Through the combination of the tw...

Cooperative Catalytic Activation of Si-H Bonds: CO2 -Based Synthesis of Formamides from Amines and Hydrosilanes under Mild Conditions.

A simple cooperative catalytic system was successfully developed for the solvent-free N-formylation of amines with CO2 and hydrosilanes under ambient conditions, which was composed of a Zn(salen) catalyst and quaternary ammonium salt. These commercially available binary components activated the Si-H bonds effectively, owing to the intermolecular synergistic effect between Lewis base and transition metal center (LB-TM), and subsequently facilitated the insertion of CO2 to form the active silyl formats, thereby leading to excellent catalytic performance at a low catalyst loading. Furthermore, the bifunctional Zn(salen) complexes, with two imidazolium-based ionic-liquid (IL) units at the 3,3'-position of salen ligand, acted as intramolecularly cooperative catalysts, and the solvent-regulated separation resulted in facile catalyst recycling and reuse.

Novel Bifunctional Zn–Sn Composite Oxide Catalyst for the Selective Synthesis of Glycerol Carbonate by Carbonylation of Glycerol with Urea

AbstractA novel Zn–Sn composite oxide is reported as a solid bifunctional catalyst for glycerol carbonylation to give glycerol carbonate in high yields. It was prepared by coprecipitation, solid‐state and evaporation methods. Physico‐chemical properties of the catalysts were investigated by XRD, N2 sorption, temperature‐programmed desorption, SEM, and TEM techniques. Coprecipitation was found to be better than the other two methods for carbonylation of glycerol. Higher activity of the catalyst was attributed to a high amount of active sites. A series of Zn–Sn composite oxides with different metal contents and effect of calcination on glycerol carbonate synthesis were also studied. The correlation of activity with total active sites of the catalyst was obtained. Zn–Sn composite catalyst with Zn/Sn molar ratio=2:1 calcined at 600 °C exhibited 96.0 % glycerol conversion with 99.6 % selectivity towards glycerol carbonate under optimized reaction conditions. The catalyst was recycled four times with a marginal decrease in activity.

Bifunctional Zn(II) complexes for recognition of non-canonical thymines in DNA bulges and G-quadruplexes.

Six Zn(II) complexes of derivatives of 1,4,7,10-tetraazacyclododecane (cyclen) were studied for binding to DNA sequences containing non-canonical thymines, including a hairpin with a single thymine bulge (T-bulge) and a G-quadruplex (H-telo) containing thymine loops. The cyclen-based macrocycles contained pendents with either two fused rings to give planar groups including quinolinone (QMC), coumarin (MCC) and quinoline (CQC) derivatives or a non-planar dansyl group (DSC). Macrocyclic complexes with three fused rings including an anthraquinone pendent (ATQ) were also studied. All Zn(II) complexes were stable in solution at micromolar concentrations and neutral pH with the Zn(L)(OH2) species prevailing for L = QMC and CQC at pH 7.5 and 100 mM NaCl. Immobilized T-bulge or H-telo G-quadruplex was used to study binding of the complexes by surface plasmon resonance (SPR) for several of the complexes. For the most part, data matched well with that obtained by isothermal calorimetry (ITC) and, for fluorescent complexes, by fluorescence titrations. Data showed that Zn(II) complexes containing planar aromatic pendents with two fused rings bound to T-bulge more tightly than complexes with non-planar pendents such as DSC. The H-telo DNA exhibited multiple binding sites for all complexes containing aromatic pendents. The complexes with two fused rings bound with low micromolar dissociation constants and two binding sites whereas a complex with three fused rings (ATQ) bound to three sites. This study shows that different pendent groups on Zn(II) cyclen complexes impart selectivity for recognition of non-canonical DNA structures.

Bifunctional pH-sensitive Zn(ii)-curcumin nanoparticles/siRNA effectively inhibit growth of human bladder cancer cells in vitro and in vivo.

To overcome drug resistance, the combination of two or more therapeutic strategies with different mechanisms has received much attention in recent years. In this study, a common approach has been used to process curcumin and Zn2+ into colloidal dispersions known as "nanoparticles", which are cheap and easy to prepare with high reproducibility. This novel vehicle has good biocompatibility and high cellular uptake for simultaneously delivering the curcumin drug and siRNA into tumor cells. Complexation of Zn2+ with curcumin enhances the aqueous solubility of the hydrophobic drug curcumin and further improves the cellular uptake and bioavailability. The acid-labile coordination Zn(ii)-O bond in Zn(ii)-curcumin drug nanoparticles (Zn(ii)-Cur NPs) can respond to tumor intracellular acidic pH environments to release curcumin, and promoting acid-triggered intracellular drug release. The positively charged Zn(ii)-Cur NPs can efficiently deliver siRNA into human bladder cancer cells, protect siRNA against enzymatic degradation, and facilitate the escape of loaded siRNA from the endosome into the cytoplasm, which successfully downregulates the targeted EIF5A2 oncogene and consequently inhibits cancer cell growth in vitro and in vivo. Proliferation and migration of cancer cells are inhibited by silencing the expression of EIF5A2 and increasing the ratio of pro-apoptotic BAX to anti-apoptotic BCL-2. In vitro and in vivo experiments have demonstrated that bifunctional Zn(ii)-Cur NPs/siEIF5A2 can combine chemotherapy with gene therapy to afford higher therapeutic efficacy than the individual therapeutic protocols.

Easily accessible bifunctional Zn(salpyr) catalysts for the formation of organic carbonates

Alkylated Zn(salpyr) complexes (salpyr = N,N′-bis[salicylidene]-3,4-pyridinediamine) were prepared and used as catalyst precursors for the formation of cyclic carbonates from a range of (functional) epoxides and CO2.

Asymmetric Alkynylation of Aldehydes Catalyzed by Bifunctional Zinc(salen) Complex

AbstractThe asymmetric alkynylation of aldehydes catalyzed by bifunctional Zn(salen) catalyst was realized. With a Kozlowski salen ligand (7e) bearing secondary basic 1‐piperidinylmethyl groups at C‐3 and C‐3′, the enhanced catalytic reactivity and stereoselectivity in comparison with that of normal salen ligands in the alkynylzinc addition to aldehydes were observed.