An Efficient Solvent-free Synthetic Technique of 4,4’-Diaminotriarylmethane Leuco Materials

An efficient, versatile and solvent-free synthetic technique of diaminotriarylmethanes was reached by treating N,N-dimethylaniline with some arylaldehydes over zirconium(IV) oxide chloride (ZrOCl2•8H2O), in which ZrOCl2•8H2O has good activity, easy availability, recovery as well as reusability.     

DTA-TG and XRD study on the reaction between ZrOCl2·8H2O and (NH4)2HPO4 for synthesis of ZrP2O7

In this paper, we report results of thermoanalytical investigation on the reaction between ZrOCl₂·8H₂O and (NH₄)₂HPO₄ in molar ratio 1:2. Differential thermal-thermogravimetric and X-ray diffraction analyses were performed in order to reveal the chemical transformations, which took place during heating of the individual compounds ZrOCl₂·8H₂O, (NH₄)₂HPO₄ and the mixture ZrOCl₂·8H₂O:2(NH₄)₂HPO₄. It was shown that the transformations in the mixture below 160 °C were connected with dehydration of ZrOCl₂·8H₂O and interaction between the components of the mixture, which resulted in the formation of NH₄Cl, NH₄H₂PO₄ and a mainly amorphous zirconium phase, most likely t-ZrO₂. The zirconium component subsequently reacted with ammonium dihydrophosphate (below 200 °C) or with dehydrated phosphate derivatives (above 200 °C), which in both cases yielded an amorphous product. The interaction between the components of the mixture resulting in the formation of ZrP₂O₇ was completed by its crystallisation at 610 °C. Our study indicates an alternative low-temperature approach for the synthesis of the technologically important ZrP₂O₇ material.     

Zirconium(IV) oxochloride complexes with xanthines and hypoxanthine

ZrO(LH)₂LCl·H₂O (LH ≡ xanthine, hypoxanthine, theophylline, theobromine) complexes are obtained by boiling under reflux 2:1 molar mixtures of ligand and ZrOCl₂·8H₂O in ethanol-triethyl orthoformate. Characterization studies suggest that these complexes are heptacoordinated polymeric, involving linear ZrOZrO chains and five terminal ligands per Zr⁴⁺ ion, i.e. two LH and one L⁻ (binding through a ring nitrogen), one chloro and one aqua ligand. Caffeine (caf) yielded under the same conditions an addition product of the (ZrOCl₂·3H₂O)₃·caf type. In this compound, caffeine is apparently not involved in coordinative bonding to the zirconium, but is retained in the crystal lattice by means of hydrogen bonds formed between aqua ligand hydrogens and the N(9), O(2) and O(6) caffeine sites.     

Spatial Distribution of Nitrogen Binding Sites in Metal-Organic Frameworks for Selective Ethane Adsorption and One-Step Ethylene Purification

The one-step purification of ethylene (C₂H₄) from mixtures containing ethane (C₂H₆) and acetylene (C₂H₂) is an industrially important yet challenging process. In this work, we present a site-engineering strategy aimed at manipulating the spatial distribution of binding sites within a confined pore space. We realized successfully by incorporating nitrogen-containing heterocycles, such as indole-5-carboxylic acid (Ind), benzimidazole-5-carboxylic acid (Bzz), and indazole-5-carboxylic acid (Izo), into the robust MOF-808 platform via post-synthetic modification. The resulting functionalized materials, namely MOF-808-Ind, MOF-808-Bzz, and MOF-808-Izo, demonstrated significantly improved selectivity for C₂H₂ and C₂H₆ over C₂H₄. MOF-808-Bzz with two uniformly distributed nitrogen binding sites gave the optimal geometry for selective ethane trapping through multiple strong C−H⋅⋅⋅N hydrogen bonds, leading to the highest C₂H₂/C₂H₄ and C₂H₆/C₂H₄ combined selectivities among known MOFs. Column breakthrough experiments validated its ability to purify C₂H₄ from ternary C₂H₂/C₂H₄/C₂H₆ mixtures in a single step.     

Influence of varying molar concentration on the properties of electrochemically-deposited zirconium-doped ZnSe thin films

The effects of molar concentration on ZnSe and Zr-doped ZnSe thin films were studied after successful synthesis by electrochemical technique. 0.1 M zinc tetraoxosulphate (VI) heptahydrate (ZnSO₄·7H₂O) and 0.1 M selenium powder respectively served as the cationic and anionic precursors while 0.1 mol% of zirconium oxidchlorid (ZrOCl₂·8H₂O) was used as the dopant. The morphology, structure, elemental, light response, and electrical features of the samples were studied. The films exhibited uniform distribution of spherical balls with crystalline peaks at (220), (221), (300), and (310) planes. The elemental composition of the film confirmed the deposition of as-synthesized elements. Improved optical characteristics and reduced band gap energies of the films from 2.4 eV to 2.0 eV were gotten upon the addition of zirconium. Electrical results showed increased material conductivity at increasing dopant percentages. The synthesized materials are potentially applied in optoelectronics and photovoltaics.     

Preparation of Zirconia Fibers via a Simple Aqueous Sol‐Gel Method

Polycrystalline tetragonal zirconia fiber was obtained by pyrolysis of precursor fibers from citrate‐acetate‐zirconium complex solution. The viscous zirconia sol with good spinnability was prepared by aging the starting solution of ZrOCl₂ · 8H₂O (ZOC) in the presence of acetic acid (HA) and citric acid (CA). The effects of molar ratio of zirconium cation to carboxylic acid and the aging time on the formation of spinnable sol were investigated. Thermogravimetric (TG) analysis, x‐ray diffraction (XRD), infrared (IR) spectra, and scanning electron microscope (SEM) techniques were used to characterize the sintered fibers. The results show that the fibers obtained at 1400°C are crack‐free with diameter of ca. 5–10 µm.     

Physicochemical processes involved in synthesis of thin films based on double oxides of the ZrO<Subscript>2</Subscript>-GeO<Subscript>2</Subscript> system

The major physicochemical processes underlying the preparation of thin films of the ZrO-GeO₂ system from film-forming solutions based on zirconium oxochloride (ZrOCl₂ · 8H₂O), germanium tetrachloride (GeCl₄), and ethanol were studied. The phase composition, structure, and physicochemical properties of the films were determined.     

一系列稀土金属有机骨架的储气以及荧光性质

合成了一系列具有高热稳定性的金属有机骨架材料RE(BTC)(H2O),(RE=Y,Tb,Eu,Yx-Tb1-x,Yx-Eu1-x),除去端基水分子后可得到具有一维孔道的空旷结构RE(BTC)。其中,Y(BTC)具有良好的氢气以及甲烷储存性能。在77 K,1 atm条件下,氢气的吸附量高达1.73wt%;在室温,4 MPa条件下,Y(BTC)的甲烷储存量达到饱和,可以达到97.7 cm3.g-1(STP),在美国能源部规定的安全储运压力(3.5 MPa)下,甲烷储存量也能达到96.0 cm3.g-1(STP),与其它同类多孔材料相比具有一定的优越性。骨架中掺杂了微量金属铽(Tb),铕(Eu)的Tbx-Y1-x(BTC)(H2O),Euy-Y1-y(BTC)(H2O)与单一金属的Tb(BTC)(H2O)和Eu(BTC)(H2O)相比,不但降低了材料的成本,而且减小了浓度淬灭对材料荧光性质的影响,优化了材料的荧光性能。     

The synthesis and properties of thin films based on double oxide system SiO2-ZrO2

The main physical and chemical processes involved in the preparation of SiO₂-ZrO₂ thin films from film-forming solutions based on zirconium oxochloride ZrOCl₂·8H₂O, tetraethoxysilane Si(C₂H₅O)₄, and ethanol were studied. The phase composition, structure and physical and chemical properties of the films were determined and the diagram composition — property was constructed.     

A Study of Physicochemical Processes in Film-forming Ethanol Solutions of Zirconium and Cobalt Salts and Properties of Thin Films Obtained on Their Base

The main physicochemical processes that occur in film-forming solutions based on zirconium oxochloride ZrOCl₂ · 8H₂O, cobalt salts CoCl₂ · 6H₂O and Co(NO₃)₂ · 6H₂O, and ethanol were studied. The intermolecular interaction in film-forming solutions was analyzed qualitatively and quantitatively.     

Study of the Cycloaddition of CO2 with Styrene Oxide Over Six-Connected spn Topology MOFs (Zr,Hf) at Room Temperature

A series of MOFs with a 6-connected spn topology were synthesized (MOF-808-(Zr, Hf), PCN-777-(Zr, Hf), MOF-818-(Zr, Hf)). Through the in situ DRIFTS of NH₃ adsorption-desorption, we found that the activated catalyst mainly contains Lewis acid sites. The effects of different organic ligands on the Lewis acid of the Zr₆ cluster were analyzed by XPS and NH₃-TPD, and the relative Lewis acidity of the same metal was obtained: PCN-777>MOF-808>MOF-818. In the Py-FTIR results, we confirmed that MOF-818 has a higher acid site density. In the activity test, MOFs with mesoporous structure showed better catalytic activity under normal temperature and pressure. Among them, MOF-818 can still maintain a high degree of crystallinity after catalysis. Finally, we use density functional theory to propose the mechanism of the cycloaddition reaction of carbon dioxide and styrene oxide. The results show that the metal is coordinated with styrene oxide and halogens attack the β carbon of the epoxide.     

Chelate formation of zirconium with xylenol orange and semi-xylenol orange

The composition, formation constants, and molar absorptivities of the chelates of zirconium ion wtih xylenol orange and semi-xylenol orange are investigated spectrophotometrically in strong acid medium at ionic strength 3.0 (NaClO₄ and HClO₄). The data obtained were processed with a newly-constructed computer program and with LETAGROP/SPEFO. In the zirconium—xylenol orange system, Zr · H₃ L, Zr· H₄L, and Zr₂ · L are present with logarithmic overall formation constants of 37.80, 38.68, 43.47, and molar absorptivities of 3.10 × 10⁴ (485 nm), 5.98 × 10⁴ (528 nm), 9.50 × 10⁴ (551 nm) I mol^-1 cm^-1, respectively. The chelates Zr · L and Zr · HL were found in the zirconium—semi-xylenol orange system with logarithmic overall formation constants of 26.25 and 27.56, and molar absorptivities of 5.70 × 10⁴ (532 nm) and 8.30 × 10⁴ (535 nm) 1 mol^-1 cm^-1, respectively. Semi-xylenol orange is more sensitive and reliable than xylenol orange as a spectrophotometric reagent for zirconium.     

ZrOCl2·8H2O as an efficient and recyclable catalyst for the one‐pot multicomponent synthesis of novel [1,3]oxazino[5,6‐c]quinolin‐5‐one derivatives

A simple, efficient and eco‐friendly procedure has been developed using ZrOCl₂·8H₂O as catalyst for the synthesis of novel [1,3]oxazino[5,6‐c]quinolin‐5‐one derivatives in aqueous ethanol at room temperature. The present methodology offers several advantages such as operational simplicity, use of ZrOCl₂·8H₂O as a green, non‐toxic, inexpensive and reusable catalyst, reusability of reaction media, high yields, mild and environmentally benign reaction conditions.     

Nanospace geometry-sensitive molecular assembly

Interaction of a molecule with micropore walls strongly depends on the micropore width. Molecules confined in the micropore tend to form an intermolecular structure inherent to each molecule/pore system in order to lower the whole molecular energy. Supercritical NO is adsorbed in micropores of zolite or activated carbon fiber in the form of a dimer at 303 K. The NO dimerization varies with the micropore width. CCl₄ molecules only in pore of pore width =1.0 nm at 303 K form a plastic crystalline structure which is observed at 246–250 K in the bulk phase. H₂O molecules are associated with each other to form an ordered assembly in carbon micropores at 303 K; the smaller the pore width, the more ordered the assembly structure. The presence of preadsorbed H₂O noticeably enhances adsorption of supercritical CH₄ in carbon micropores at 303 K due to methane nanohydrate formation, which has an optimum pore width of 1 nm.     

Effect of the Ethanol/BTC Ratio on the Methane Uptake of Mechanochemically Synthesized MOF-199

We report on a detailed textural analysis of mechanochemically synthesized MOF-199 including N₂ adsorption-desorption and CO₂ adsorption isotherms data at 77 K and 273 K (up to atmospheric pressure), respectively, and CH₄ adsorption data at 298 K (up to 35 bar). We used the isotherm adsorption data to determine the micropore volume of the MOF-199 structures, to establish their methane uptake capacity and to understand how these properties depended on the Ethanol/BTC ratio used during the synthesis. The maximum methane uptake capacity for our specimens was recorded at 130 v/v at 35 bars. These results open an avenue for a better understanding of alternative manufacturing processes of MOF structures for gas storage applications.     

Highly anti–anti selective synthesis of bis-β-amino ketones via three-component direct Mannich-type reaction of terephthalaldehyde catalyzed by ZrOCl2·8H2O

At room temperature, zirconium oxychloride (ZrOCl₂·8H₂O) efficiently catalyzes the direct Mannich-type reaction of a variety of in situ generated bis-imines using terephthalaldehyde and anilines with ketones in a three-component reaction at room temperature. The reaction proceeds rapidly and affords the corresponding bis-β-amino ketones in good-to-high yields with good-to-excellent anti–anti selectivity.     

Ligand controlled structure of cadmium(II) metal-organic frameworks for fluorescence sensing of Fe3+ ion and nitroaromatic compounds

2-Fold interpenetrating 3D framework for selective adsorption of CO₂ over CH₄ and fluorescence detection of Fe³⁺ ions and nitroaromatic compounds through fluorescence quenching.     

MOF-808/BiOCl复合材料的制备及其光催化性能

将高稳定性的MOF-808与BiOCl结合,采用简便的水热法制备出新型MOF-808/BiOCl复合异质结材料。以环丙沙星(CIP)为污染物,探究复合材料MOF-808/BiOCl对CIP的光催化性能。发现含有10% MOF-808的复合材料(MOF-808/BiOCl-10%)表现出最佳的光催化活性。在紫外光照射20 min内,MOF-808/BiOCl-10%对CIP的光催化降解效率高达94.7%。通过X射线粉末衍射、扫描电镜、红外光谱、荧光光谱、紫外可见漫反射光谱、光电流、电化学阻抗等表征技术来考察材料的物相组成、形貌以及光电化学性质。紫外可见漫反射光谱的结果表明,MOF-808/BiOCl-10%材料光吸收范围得到提高。同时进行了自由基捕获实验。基于以上实验数据,提出了MOF-808/BiOCl复合材料可能的光催化机理。     

Zirconium(IV) oxide chloride and anhydrous copper(II) sulfate mediated synthesis of 2‐substituted benzothiazoles

A simple, fast and efficient benign procedure has been developed for one‐pot synthesis of 2‐substituted benzothiazoles in the presence of zirconium(IV) oxide chloride octahydrate (ZrOCl₂·8H₂O) and anhydrous copper(II) sulfate. The reaction of 2‐aminothiophenol with aldehydes and anhydrides was carried out efficiently in solvent‐free conditions with or without microwave irradiation, and adducts were produced in good to excellent yields. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:136–141, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20191     

An Effective Method to Construct Cluster‐based Frameworks with Multifarious Structures,Luminescence, and Sorption Properties

An effective method was developed for the synthesis of three cluster‐based frameworks with multifarious secondary building units (SBUs) and various structures, which were formulated as [Me₂NH₂]₂[Zn₁₀(BTC)₆(μ₃‐O)(μ₄‐O)(H₂O)₅] · 3DMA · 9H₂O ( FJI ‐ 3 ), [Me₂NH₂]₂[Zn₉(μ₃‐OH)₂(BTC)₆(H₂O)₃] · 5DMA · 6H₂O ( FJI ‐ 4 ) and [Me₂NH₂][Zn₃(μ₃‐OH)(BTC)₂DMF] · H₂O ( FJI ‐ 5 ) (H₃BTC = 1,3,5‐benzenetricarboxylic acid, DMA = N,N′‐dimethyl acetamide and DMF = N,N′‐dimethyl formamide), respectively. X‐ray structural analysis reveals that FJI ‐ 3 displays 3D highly porous metal‐organic framework with four kinds of microporous cages constructed by two paddle‐wheel Zn₂(CO₂)₄, trimeric Zn₃O(CO₂)₆, and tetrameric Zn₄O(CO₂)₆ SBUs. FJI ‐ 4 exhibits 3D microporous MOFs with a dodecahedral cavities built by paddle‐wheel Zn₂(CO₂)₄ and trimeric Zn₃O(CO₂)₆. FJI ‐ 5 shows 3D microporous MOFs with an 1D channel assembled by the Zn₃O(CO₂)₆ SBUs. In addition, the fluorescence and sorption properties in these cluster‐based frameworks were also investigated. Furthermore, the method employed in this work may provide an useful approach to the design and synthesis of novel cluster‐based frameworks.