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Modulating the anisotropic growth rate of zeolites to tailor their physicochemical properties holds significant promise across various fields, such as catalysis and adsorption. However, achieving this objective using commercially available small molecules remains a fascinating yet challenging task in zeolite crystallization, particularly for zeolites with a strong growth orientation. Herein, we demonstrate the synthesis of well-faceted nanoplatelet mordenite (MOR) zeolite with a thickness of 80 nm along the (100) direction in a low alkaline gel system utilizing tetraethylammonium hydroxide (TEAOH) and hexamethylenimine (HMI) as dual templates. Time-resolved analysis of precursor evolution reveals the unique crystallization pathway of in situ crystal transformation induced by the exchange of structure-directing agents. The dissolved species maintain some "memory" of MCM-56 due to the strong interaction between the silanol groups and HMI, which inhibits the attachment of incoming building units to the MOR phase and benefits the formation of nanoplatelet MOR. A comprehensive investigation into key factors influencing nanoplatelet MOR zeolite formation demonstrated that metastable MCM-56 and the crystallization rate play pivotal roles. Moreover, fine-tuning the crystallization rate allows customization of the crystal size and aspect ratio for nanoplatelet MOR zeolite. The catalytic performance of the nanoplatelet MOR zeolite in the alkylation of benzene with benzyl alcohol is enhanced compared to its bulk counterpart. [ABSTRACT FROM AUTHOR]

Research was conducted to investigate the synthesis, characterization, and luminescence of europium(III) Schiff base complexes. Luminescence in solution was examined both at 77 K and at room temperature where the triplet-state energies of the complexes were established by calculations with the corresponding Y(III) complexes. Results are in good agreement with previously reported europium polyelectrolytes.

Two new soluble, linear cerium(IV) coordination polymers may be best synthesized by step growth chelation polymerization between cerium(IV) alkoxide or cerium(IV) acetylacetonate and a pre-made Schiff-base. After fractionation, the molecular weight of the polymers are 31500 and 28000 respectively. The polymers have high solubilities in organic solvents and show good thermal stability. The flexibility and solubility of the compounds may be improved by addition of methyl groups to the Schiff-bases and polymers.

A new methodology enables the synthesis of lanthanide(III) disalicylidene-1, 2-phenylenediamine (H2dsp) Schiff-base complexes. UV absorption and magnetic resonance spectroscopic studies of these complexes reveal the presence of an equilibrium in solution. In complexes of the Ln2dsp3 type, one dsp2- ligand simultaneously coordinates with two Ln3+ ions through its oxygen atoms. Analysis of the intensity of different peaks in the NMR spectra confirms the presence of various ions in dimethyl-sulfoxide solution (DMSO). The thermal stability and solubility of the complexes in DMSO depend on the type of ligand and ion.

The adsorptive separation properties of M-BTC isostructural series (M = Ti, Fe, Cu, Co, Ru, Mo) for methanol-acetone mixtures were investigated by using various computational procedures of grand canonical Monte Carlo simulations (GCMC), density functional theory (DFT), and ideal adsorbed solution theory (IAST), following with comprehensive understanding of adsorbate-metal interactions on the adsorptive separation behaviors. The obtained results showed that the single component adsorptions were driven by adsorbate-framework interactions at low pressures and by framework structures at high pressures, among which the mass effects, electrostatics, and geometric accessibility of the metal sites also played roles. In the case of methanol-acetone separation, the selectivity of methanol on M-BTCs decreased with rising pressures due to the pressure-dependent separation mechanisms: the cooperative effects between methanol and acetone hindered the separation at low pressures, whereas the competitive effects of acetone further resulted in the lower selectivity at high pressures. Among these M-BTCs, Ti and Fe analogues exhibited the highest thermodynamic methanol/acetone selectivity, making them promising for adsorptive methanol/acetone separation processes. The investigation provides mechanistic insights on how the nature of metal centers affects the adsorption properties of MOFs, and will further promote the rational design of new MOF materials for effective gas mixture separation.

The adsorption and separation properties of benzene and toluene on the zirconium-based frameworks UiO-66, -67, -68, and their functional analogues UiO-Phe and UiO-Me2 were studied using grand canonical Monte Carlo simulations, density functional theory, and ideal adsorbed solution theory. Remarkable higher adsorption uptakes of benzene and toluene at low pressures on UiO-Phe and -Me2 were found compared to their parent framework UiO-67. It can be ascribed to the presence of functional groups (aromatic rings and methyl groups) that significantly intensified the adsorption, majorly by reducing the effective pore size and increasing the interaction strength with the adsorbates. At high pressures, the pore volumes and accessible surfaces of the frameworks turned out to be the dominant factors governing the adsorption. In the case of toluene/benzene separation, toluene selectivities of UiOs showed a two-stage separation behavior at the measured pressure range, resulting from the greater interaction affinities of toluene at low pressures and steric hindrance effects at high pressures. Additionally, the counterbalancing factors of enhanced π delocalization and suitable pore size of UiO-Phe gave rise to the highest toluene selectivity, suggesting the ligand functionalization strategy could reach both high adsorption capacity and separation selectivity from aromatic mixtures at low concentrations.

Zeolites are microporous materials with pores and channels of molecular dimensions that find numerous applications in catalysis, separations, ion exchange, etc. However, whereas uniformity of micropore size is a most desirable and enabling characteristic for many of their uses, in certain cases, for example in reactions involving bulky molecules, it is a limitation. For this reason, synthesis of hierarchical zeolites with micro- and mesoporosity is of considerable interest as a way to control molecular traffic for improved catalytic and separation performance. Herein, we report a general synthesis route for the confined synthesis of zeolites within three-dimensionally ordered mesoporous carbon templates by conventional hydrothermal synthesis. Various zeolites, including BEA, LTA, FAU, and LTL, with three-dimensionally ordered mesoporous-imprinted structure have been synthesized by this approach. It is expected that these hierarchical zeolite materials will provide building blocks for thin-film and other syntheses and may provide a basis for quantitatively studying the mass-transfer limitation on the catalytic performance of zeolite catalysts.