Ruren Xu

Insight into the construction of open-framework aluminophosphates

Over the past twenty five years, a class of open-framework aluminophosphates, denoted AlPOs, has been prepared with neutral zeolitic frameworks and anionic frameworks showing wonderfully complex structural and compositional diversity. An insight into the construction of open-framework AlPOs revealing their general structural features and topological chemistry is provided in this tutorial review, and the role of templating and the designed construction and synthesis of AlPOs are discussed.

Zeolite-coated mesh film for efficient oil–water separation

Oil–water separations are helping with urgent issues due to increasing industrial oily wastewater, as well as frequent oil spill accidents. Membrane-based materials with special wettability are desired to separate oils from water. However, fabrication of energy-efficient and stable membranes that are suitable for practical oil–water separation remains challenging. Zeolite films have attracted intense research interest due to their unique pore character, excellent chemical, thermal and mechanical stability, etc. Here we first demonstrate zeolite-coated mesh films for gravity-driven oil–water separation. High separation efficiency of various oils can be achieved based on the excellent superhydrophilicity and underwater superoleophobicity of the zeolite surface. Flux and intrusion pressure are tunable by simply changing the pore size, dependent on the crystallization time of the zeolite crystals, of the zeolite meshes. More importantly, such films are corrosion-resistant in the presence of corrosive media, which gives them promise as candidates in practical applications of oil–water separation.

Accelerated crystallization of zeolites via hydroxyl free radicals

Radically faster synthesis Zeolite synthesis normally proceeds under basic conditions that allow the oxide bridges between aluminum and silicon atoms to break and reform. Feng et al. show that the formation of hydroxyl radicals, either by irradiation with ultraviolet light or with the Fenton reagent, can speed up the formation of the crystallized zeolite by about a factor of 2. Science, this issue p. 1188 Hydroxyl radicals generated with ultraviolet light or Fenton reagents can approximately double the rate of zeolite synthesis. In the hydrothermal crystallization of zeolites from basic media, hydroxide ions (OH–) catalyze the depolymerization of the aluminosilicate gel by breaking the Si,Al–O–Si,Al bonds and catalyze the polymerization of the aluminosilicate anions around the hydrated cation species by remaking the Si,Al–O–Si,Al bonds. We report that hydroxyl free radicals (•OH) are involved in the zeolite crystallization under hydrothermal conditions. The crystallization processes of zeolites—such as Na–A, Na–X, NaZ–21, and silicalite-1—can be accelerated with hydroxyl free radicals generated by ultraviolet irradiation or Fenton’s reagent.

Chiral zeolitic materials: structural insights and synthetic challenges

Chiral zeolitic materials are of both fundamental and practical interest because they can combine both shape selectivity and enantioselectivity, which are desirable for asymmetric catalysis and separation. However, the synthesis of such materials remains a significant challenge in the field of zeolite science. This feature article will focus on a family of four-connected zeolite frameworks and related inorganic open frameworks with fascinating chiral structural features, aiming to provide an insight into the origin of chirality in these structures. Some approaches to the design of chiral zeolite frameworks, as well as synthesis routes and challenges to the chiral zeolitic materials are also discussed.

A crystalline germanate with mesoporous 30-ring channels.

A novel germanate |C(6)N(2)H(18)|(30)[Ge(9)O(18)X(4)](6)[Ge(7)O(14)X(3)](4)[Ge(7)O(14.42)X(2.58)](8)[GeX(2)](1.73) (X = OH, F) with 30-ring channels built from Ge(7)O(14)X(3) (Ge(7)) and Ge(9)O(18)X(4) (Ge(9)) clusters was obtained under solvothermal conditions. It has a mesoporous pore of 13.0 x 21.4 A(2), which represents the largest pore ring found in crystalline open-framework materials. The framework can be described as a 3-D net structure and viewed as introducing Ge(7) and Ge(9) clusters into the 4,8-heterocoordinated csq net.

A Germanate Built from a 68126 Cavity Cotemplated by an (H2O)16 Cluster and 2‐Methylpiperazine

Totally tubular: A new tubular germanate is cotemplated by 2-methylpiperazine and an (H2O)16 cluster in a hydro(solvo)thermal synthesis. The germanate features a large, highly symmetric 68126 cavity (see picture; yellow sphere) built from 12 Ge7X19 (X=O, OH, F) clusters (GeX6 red, GeX5 yellow, GeX4 green).

Encapsulation and luminescent property of tetrakis (1-(2-thenoyl)-3,3,3-trifluoracetate) europium N-hexadecyl pyridinium in modified Si-MCM-41

Abstract Eu(TTA)4C5H5NC16H33 (TTA:1-(2-thenoyl)-3,3,3-trifluoracetate) is encapsulated in Si–MCM-41 modified with N-(3-trimethoxysilylethyl)ethylenediamine. The X-ray photoelectorn spectroscopy and UV–visible spectra of the rare earth (RE) complex and the assembly prove that the RE complex is dispersed in the channels of the modified Si–MCM-41. The emission spectrum of the assembly shows only a 5 D 0 → 7 F 2 transition. As compared with the RE complex itself, the lifetime of the assembly becomes longer, and its stability under the UV radiation is much better.

A novel catalyst of copper hydroxyphosphate with high activity in wet oxidation of aromatics

Abstract A novel catalyst of copper hydroxyphosphate (Cu 2 (OH)PO 4 ) that has neither microporous nor mesoporous pores was successfully synthesized by a hydrothermal method. Catalytic data in the hydroxylation of phenol, benzene and naphthol by hydrogen peroxide showed that copper hydroxyphosphate is a very active catalyst. Comparison of various catalysts on phenol hydroxylation suggests that the unusual catalytic activity on the Cu 2 (OH)PO 4 catalyst may be dependent on the unique structure of as-synthesized Cu 2 (OH)PO 4 . Characterization of catalytic phenol hydroxylation over Cu 2 (OH)PO 4 catalyst by electron spin resonance (ESR) gives very strong signals assigned to hydroxyl radical (•OH) species, the intensities of which are linearly related to the catalytic conversion, suggesting that hydroxyl radicals are important intermediates in the catalysis.

Ionothermal Synthesis of Extra‐Large‐Pore Open‐Framework Nickel Phosphite 5 H3O⋅[Ni8(HPO3)9Cl3]⋅1.5 H2O: Magnetic Anisotropy of the Antiferromagnetism

The chemistry of inorganic open-framework materials is one of the most active areas of chemical research because of their potential applications as absorbents, ion exchangers, and catalysts in heterogeneous catalysis. A challenging target in this field is the design and synthesis of extra-large microporous open frameworks so that catalysis and separation can be performed on large molecules. To achieve large pore openings, several approaches toward synthesis of materials with extra-large pores have been explored in the past few years. In particular, a number of interrupted open-framework phosphates with extra-large channels have been synthesized hydro-/solvothermally in the presence of organic amines as structure-directing agents. Notably, replacement of tetrahedral phosphate groups PO4 3 by pseudopyramidal phosphite units HPO3 2 that can reduce the M-O-P connectivity would generate more-open interrupted frameworks. By using organic amines as structure-directing agents under hydro-/solvothermal conditions, several metal phosphites with extra-large pore openings have been prepared by us and others. Notable examples are cobalt phosphite CoHPOCJ2 with 18-ring channels, ZnHPO-CJ1 and Cr-NKU-24 with extra-large 24-ring channels, and NTHU-5 with 26ring channels. Besides their traditional applications, microporous openframework materials are finding new applications as advanced functional materials in optics, electronics, magnetism, and so on. Currently, the magnetic properties of porous open frameworks are attracting much attention. Generation of open-framework materials that order magnetically is an important goal in materials chemistry. Pillaring of inorganic layers having high magneto-anisotropy is an important strategy for the generation of porous magnets. Notable examples are inorganic–organic hybrid 3D open frameworks originating from pillaring of inorganic metal hydroxides by amines or bicarboxylates, which show multiple magnetic properties. However, accounts on obtaining 3D inorganic open-framework magnets by pillaring lower-dimensional highly magneto-anisotropic systems are still rare. Open-framework materials are typically synthesized by hydro-/solvothermal methods. Ionothermal synthesis, that is, the use of an ionic liquid as solvent and sometimes structuredirecting agent in the preparation of microporous crystalline solids, is currently receiving great attention because of the different chemistry of ionic-liquid solvent systems compared to the traditionally used water/alcohols in hydro-/solvothermal synthesis. With the aim of exploring new porous materials with interesting magnetic properties, we report herein the first ionothermal synthesis of an open-framework nickel phosphite, namely, 5H3O·[Ni8(HPO3)9Cl3]·1.5 H2O (JIS-3) with extra-large 18-ring channels. We found that JIS3 shows antiferromagnetic ordering, and investigated the magnetic anisotropy by measurements on aligned single crystals. JIS-3 was prepared ionothermally from a mixture of the ionic liquid 3-methyl-1-pentylimidazolium hexafluorophosphate ([PMim][PF6]), NiCl2·6H2O, and H3PO3 in a molar ratio of 10:1:2 at 130 8C. The phase purity was confirmed by the agreement between the experimental powder X-ray diffraction (XRD) pattern and the simulated pattern based on structure analysis (Figure S1, Supporting Information). The presence of Cl in the product was confirmed by X-ray photoelectron and energy-dispersive X-ray spectroscopic measurements (Figures S2 and S3, Supporting Information). Single-crystal structural analysis revealed that the structure of the JIS-3 anionic framework consists of [Ni8(HPO3)9Cl3] 5 units (Figure 1). Charge balance of the anionic framework is achieved by protonated water molecules located in channels. Each asymmetric unit contains two crystallographically distinct Ni sites and two crystallographically distinct P sites (Figure S4, Supporting Information). The Ni atoms are in a distorted octahedral environment: Ni(1) is coordinated to one m-O, one m-Cl, and four m3-O atoms forming Ni-O-P and Ni-O-Ni bonds; Ni(2), which lies on the threefold axis is coordinated to six m3-O atoms to form six [*] H. Xing, W. Yang, T. Su, Dr. Y. Li, J. Xu, Prof. J. Yu, Prof. R. Xu State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry, Jilin University Changchun 130012 (P. R. China) Fax: (+ 86)431-8516-8608 E-mail: jihong@jlu.edu.cn

Template-assisted self-assembly of macro–micro bifunctional porous materials

The preparation of macro–micro bifunctional porous materials has been accomplished by a well-controlled, vacuum-assisted technique. Monodisperse polystyrene latex spheres were ordered into close-packed arrays by slow sedimentation, allowing a high flux of water through the interstices between latex spheres. Zeolite LTA, FAU, LTL, BEA, MFI and Si-MFI nanocrystals, synthesized by hydrothermal procedures, permeated the interstices of latex spheres under the driving force of flowing water. After drying and calcination at 500°C, both the latex spheres and zeolite structure-directing molecules were removed, followed by the formation of products consisting of both crystalline micropores and periodic, interconnected networks of submicron macropores. XRD, SEM, TEM, IR, TG/DTA, ICP and N2 adsorption–desorption measurements were performed to monitor the preparation and to characterize the properties of the macro–micro bifunctional porous materials. The materials presented in this paper combine the benefits of both the micropore and macropore regimes. They could potentially improve the efficiency of both separation and catalysis of zeolites.