Stable zeolites that have larger pore apertures and a three-dimensional pore topology are of interest because they could be used to adsorb larger molecules, particularly for application in oil refining. Several large-pore zeolitic materials with channels formed by openings of more than 12 rings are known, but all of them have a one-dimensional channel system that limits their use in catalysis. We report the synthesis and some characterizations of IM-12, a thermally stable germanium-containing zeolite that contains the first two-dimensional channel system with extra-large pores formed by 14- and 12-ring channels.

The field of multifunctional materials has seen very rapid progress since the discovery of structures with a variety of technologically useful properties such as nanoporosity, [1][2][3] luminescence, and magnetism for sensors, [4][5][6] lasers, [7,8] nonlinear optics, [9] displays, [10] and electroluminescent devices.[11]After these discoveries, one of the most appealing aims is to explore multifunctionality, especially in designed materials, which combine in the same crystal a set of well-defined properties for specific applications. Lanthanide-based porous metal-organic frameworks (Ln-MOFs) [12][13][14][15][16][17] are excellent candidates to create multifunctional materials for sensors, provided that their photoluminescence and emission lifetimes are not influenced at ambient conditions by the presence of water. [5,[18][19][20] Existing Ln-MOF materials are thermally stable in air only up to approximately 673 K, [5,18,21] while pore diameters are too small to allow the diffusion of molecules of interest. [21,22] These properties preclude their use in luminescence sensors working in the presence of moisture at ambient temperature.MOFs that combine magnetic and anisotropic properties with high emission quantum yields under ambient conditions will open new possibilities for low-cost sensors.[23] Herein, we have synthesized, by rational design, novel crystalline MOFs containing rare-earth ions that combine hydrophobicity, high adsorption capacity, high thermal resistance, anisotropic photoluminescence, and magnetic properties. These materials preserve their photoluminescence properties in the presence of water and show excellent sensor capabilities.For achieving the above properties, we have chosen an organic spacer that fulfils the following requirements: high hydrophobicity, antenna effect, strong interaction with the metal center, and at least two coordination centers in order to obtain microporous 3D structures. High hydrophobicity was attained with ultrahydrophobic ligands, such as multiaromatic and C(sp 3 ) fluorinated spacers. The antenna effect can be present in a spacer with aromatic or multiaromatic groups. Moreover, rare-earth ions have high affinity for oxygencontaining molecules, for example those with carboxy groups, which produce robust framework architectures.[24] One spacer that fulfills the above requirements and that can be adequate to synthesize MOFs [25][26][27] is 4,4'-(hexafluoroisopropylidene)-bis(benzoic acid) (HFIPBB).Herein, under appropriate synthesis conditions and in the presence of HFIPBB, new Ln 3+ -based materials ITQMOF-1 and ITQMOF-2 (ITQMOF = Instituto de Tecnologia Quimica Metal Organic Framework), with similar properties but different crystallographic structures, have been obtained. To obtain the desired properties (luminescence and magnetism), different samples have been prepared with all the Ln elements except for the radioactive promethium. For mixed Ln 3+ samples, their molar composition (%) is given in parenthesis.The ITQMOF-1 material was obtained by reacting the HFIPBB...

Small but important: A miniaturized prototype for pH sensing in the pH range 5–7.5 has been constructed from a photoluminescent Eu3+ metal–organic framework that contains two different Eu3+ sites (Eu1 and Eu2; see picture) and self‐assembles through hydrogen bonding and π–π interactions. This material has a very high quantum yield and an excellent balance between absorption, energy transfer, and emission rate.

No abstract

The nature and spectroscopic expression of external surface sites of zeolites, in particular ZSM-5, is a long-debated question. Herein, we use three cutting-edge techniques: Fouriertransform infrared spectroscopy (FTIR) with Fourier selfdeconvolution (FSD), high magnetic field proton NMR spectroscopy under fast magic-angle spinning (MAS) and periodic boundary Density Functional Theory (DFT) calculations to study external surface models and analyze the effect of crystallite size. This provides an unequaled description of the various kinds of hydroxyl groups and of their proximities. The hydrogen-bond donor, acceptor or isolated nature of the hydroxyls results in distinct signals both in FTIR and NMR spectra, but the peak assignment is not the same from one technique to the other when the chemical nature of the hydroxyl changes. Bridging Si−(OH)− Al groups and Al−(H 2 O) lead to overlapping signals in one-dimensional 1 H MAS NMR, whereas their contributions are strongly different in FTIR spectra. However, quantification and proximity assessment could only be obtained by 1 H MAS NMR. With DFT, we confirm previous assignments for silanols and Si−(OH)−Al bridging OH groups. Other signals (between 3750 and 3600 cm −1 , and between 1 and 4 ppm) are not only assigned to extra-framework species (which we confirm with dedicated models), but also enclose the signature of sites exposed at the external surface of ZSM-5. In particular, Al−(H 2 O) species (∼3665 cm −1 ; 3.8, 2.6 ppm) and silanol−Al (∼3740, 3720, 3665 cm −1 ; 2.6, 2.2 ppm) contribute to several features depending on their environment. μ 1 -Al−OH are also present at the external surface in low amount, with a 3780 cm −1 signal in IR, and weak signals in the 0−2 ppm interval in 1 H MAS NMR.

16 ][Ge 13.8 Si 62.2 O 152 ], an extra-large pore zeolite is prepared from a fluoride-free synthesis medium in the presence of organic (6R,10S)-6,10-dimethyl-5-azoniaspiro[4,5]decane cations as structure directing agent. This material displays a high thermal stability and high adsorption capacity. It contains the first two-dimensional channel system with extra-large pores formed by 14-and 12-membered ring channels and could be used to adsorb larger molecules, particularly for application in oil refining. -(PAILLAUD*, J.-L.; HARBUZARU, B.; PATARIN,

The field of multifunctional materials has seen very rapid progress since the discovery of structures with a variety of technologically useful properties such as nanoporosity, [1][2][3] luminescence, and magnetism for sensors, [4][5][6] lasers, [7,8] nonlinear optics, [9] displays, [10] and electroluminescent devices.[11]After these discoveries, one of the most appealing aims is to explore multifunctionality, especially in designed materials, which combine in the same crystal a set of well-defined properties for specific applications. Lanthanide-based porous metal-organic frameworks (Ln-MOFs) [12][13][14][15][16][17] are excellent candidates to create multifunctional materials for sensors, provided that their photoluminescence and emission lifetimes are not influenced at ambient conditions by the presence of water. [5,[18][19][20] Existing Ln-MOF materials are thermally stable in air only up to approximately 673 K, [5,18,21] while pore diameters are too small to allow the diffusion of molecules of interest. [21,22] These properties preclude their use in luminescence sensors working in the presence of moisture at ambient temperature.MOFs that combine magnetic and anisotropic properties with high emission quantum yields under ambient conditions will open new possibilities for low-cost sensors.[23] Herein, we have synthesized, by rational design, novel crystalline MOFs containing rare-earth ions that combine hydrophobicity, high adsorption capacity, high thermal resistance, anisotropic photoluminescence, and magnetic properties. These materials preserve their photoluminescence properties in the presence of water and show excellent sensor capabilities.For achieving the above properties, we have chosen an organic spacer that fulfils the following requirements: high hydrophobicity, antenna effect, strong interaction with the metal center, and at least two coordination centers in order to obtain microporous 3D structures. High hydrophobicity was attained with ultrahydrophobic ligands, such as multiaromatic and C(sp 3 ) fluorinated spacers. The antenna effect can be present in a spacer with aromatic or multiaromatic groups. Moreover, rare-earth ions have high affinity for oxygencontaining molecules, for example those with carboxy groups, which produce robust framework architectures.[24] One spacer that fulfills the above requirements and that can be adequate to synthesize MOFs [25][26][27] is 4,4'-(hexafluoroisopropylidene)-bis(benzoic acid) (HFIPBB).Herein, under appropriate synthesis conditions and in the presence of HFIPBB, new Ln 3+ -based materials ITQMOF-1 and ITQMOF-2 (ITQMOF = Instituto de Tecnologia Quimica Metal Organic Framework), with similar properties but different crystallographic structures, have been obtained. To obtain the desired properties (luminescence and magnetism), different samples have been prepared with all the Ln elements except for the radioactive promethium. For mixed Ln 3+ samples, their molar composition (%) is given in parenthesis.The ITQMOF-1 material was obtained by reacting the HFIPBB...

MFI-type materials with a lamellar morphology were successfully synthesized by using mononitrogen surfactants specifically designed by molecular modelling. The mononitrogen surfactants directed the recrystallization of a crystalline layered polysilicate formed in situ, the magadiite, into a zeolite ZSM-5.Moreover, the surfactants allow the preservation of the lamellar shape of the magadiite and inhibit a further growth into one dimension, leading to the formation of zeolite ZSM-5 nanosheets with a thickness comprised between 2 and 3 nm and a Si/Al ratio of 24. This simple approach paves a new way for obtaining zeolite materials of controlled size and shape for specific catalytic applications.