Cu(3)(BTC)(2) with an incorporated Keggin polyoxometalate was demonstrated to be stable under steaming conditions up to 483 K, while the isostructural HKUST-1 degrades and transforms into [Cu(2)OH(BTC)(H(2)O)](n)·2nH(2)O from 343 K onwards.

Self-supported oligo-layered ZnAlEu LDH nanotubes (∅ 20 nm) self-assemble upon controlled hydrolysis of the metal ions (Zn, Al, Eu) in the presence of 1,3,5-benzenetricarboxylate anions and non-ionic worm-like micelles. Their high surface area and easily accessible cylindrical mesopores (175 m g; 0.75 cm g) facilitate interaction with 5 nm CdTe quantum dots, enhancing the overall luminescence behavior.

HKUST-1 is one of the popular metal-organic frameworks (MOFs). The formation of this MOF is significantly accelerated by adding Keggin polyoxometalate anions to the synthesis solution. In this paper the chemistry behind this observation was investigated. Upon addition of Keggin type H 3 PW 12 O 40 heteropolyacid the speciation of Cu 2+ cations in ethanol : H 2 O mixture drastically changes. Combining EPR and XANES measurements with accurate pH measurements and prediction of Cu 2+ hydrolysis provides strong evidence for surface induced hydrolysis and consequent dimerisation of monomeric Cu 2+ species on Keggin ions in acidic conditions. This enables paddle wheel formation, hence explaining the instantaneous precipitation of Cu 3 (BTC) 2 at room temperature and the systematic encapsulation of Keggin ions in its pores.

X‐ray spectroscopy: Substoichiometric encapsulation of polyoxometalate ions into a metal–organic framework results in a fully functional cation exchanger with accessible porosity. Cu2+ cations compensating the charge of [PW12O40]3− in the as‐synthesized material can be exchanged with cations such as Na+ and Eu3+. When exchanged with Eu3+, the material appears bright red under UV irradiation (see figure).

The physico-chemical properties of layered double hydroxides (LDHs) can be tailored to a large extent by exploiting the flexibility of their chemical composition. This report describes the synthesis and the detailed quantitative characterization of the luminescence properties of novel Eu 3+ -containing LDHs intercalated by carboxylate and β-diketonate anionic ligands. To prepare the samples, Zn 2+ , Al 3+ and Eu 3+ were coprecipitated in a ligand-rich solution containing 1,3,5benzenetricarboxylate (BTC), acetylacetonate (ACAC), and thenoyltrifluoroacetonate (TTA).Powder X-ray diffraction is supportive for the intercalation of BTC and ACAC. The presence of TTA is revealed by CHN quantification and by the photoluminescence results. Detailed spectroscopic investigation of these materials demonstrates quantum efficiencies (η) of 15 to 17% emerging from the symmetry reduction engendered by the organic ligands in the vicinity of

A new concept of luminescent host-guest materials was developed by introduction of Eu(3+) into COK-16, a HKUST-1 type hybrid metal-organic framework (MOF) with cation exchange properties. In Eu@COK-16, the luminescent ion resides in the pore system of the MOF. The luminescence properties of Eu@COK-16 have been studied based on excitation and emission, allowing analysis of intramolecular energy-transfer processes from the COK-16 host to the exchanged Eu(3+) ions. Both the framework trimesate (BTC) and encapsulated [PW12O40](3-) ions contribute to energy transfer. Since the antenna molecules (BTC) are part of the framework structure and [PW12O40](3-) ions only partly occupy one of the three types of cavities in the structure, a large fraction of the pore volume in this host sensitized luminescent MOF remains available for catalysis applications or adsorption of additional sensitizing molecules. The material structure was determined from a combination of elemental analysis, XAS, XRD, electron and luminescence spectroscopy.

Layered double hydroxides (LDHs) containing Eu 3+ activators were synthesized by coprecipitation of Zn 2+ , Al 3+ , and Eu 3+ in alkaline NO 3 − -rich aqueous solution. Upon calcination, these materials transform into a crystalline ZnO solid solution containing Al and Eu. For suitably low calcination temperatures, this phase can be restored to LDH by rehydration in water, a feature known as the memory effect. During rehydration of an LDH, new anionic species can be intercalated and functionalized, obtaining desired physicochemical properties. This work explores the memory effect as a route to produce luminescent LDHs intercalated with 1,3,5-benzenetricarboxylic acid (BTC), a known anionic photosensitizer for Eu 3+ . Time-dependent hydration of calcined LDHs in a BTC-rich aqueous solution resulted in the recovery of the lamellar phase and in the intercalation with BTC. The interaction of this photosensitizer with Eu 3+ in the recovered hydroxide layers gave rise to efficient energy transfer from the BTC antennae to the Eu 3+ ions, providing a useful tool to monitor the rehydration process of the calcined LDHs.

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