This critical review will be of interest to the experts in porous solids (including catalysis), but also solid state chemists and physicists. It presents the state-of-the-art on hybrid porous solids, their advantages, their new routes of synthesis, the structural concepts useful for their ‘design’, aiming at reaching very large pores. Their dynamic properties and the possibility of predicting their structure are described. The large tunability of the pore size leads to unprecedented properties and applications. They concern adsorption of species, storage and delivery and the physical properties of the dense phases. (323 references)

Hybrid porous solids: past, present, future

Surfactant-Assisted Synthesis of Nanoscale Gadolinium Metal–Organic Frameworks for Potential Multimodal Imaging†

Two novel isostructural lanthanide metal–organic frameworks (Ln-MOFs), [Ln2(BPDC)(BDC)2(H2O)2]n (Ln = Eu (1) and Tb (2)), have been successfully synthesized via a mixed ligand approach using 2,2′-bipyridine-3,3′-dicarboxylic acid (H2BPDC) and 1,4-benzenedicarboxylic acid (H2BDC) under hydrothermal conditions. Structural analysis shows that two lanthanide ions are 4-fold linked by two κ1-κ1-μ2 carboxylates from BDC2– and the other two κ2-κ1-μ2 carboxylates from BPDC2– to form a binuclear core. The binuclear units are further connected by BDC2– and BPDC2– to build a three-dimensional framework possessing tfz-d topology with the short (Schlafli) vertex symbol {43}2{46·618·84}. Moreover, isostructural doped Ln-MOFs [Eu2xTb2(1–x)(BPDC)(BDC)2(H2O)2]n (x = 0.1 (1a), 0.3 (1b), 0.5 (1c), 0.7 (1d), and 0.9 (1e)) were also successfully synthesized. Thermal gravimetric analyses (TGA) reveal high thermal stability of these Ln-MOFs. Luminescent measurements indicate that the characteristic sharp emission bands of Eu3+ ...

Highly Selective Luminescent Sensing of Fluoride and Organic Small-Molecule Pollutants Based on Novel Lanthanide Metal–Organic Frameworks

By using the bent linker 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) (H2hippb), whose central atom is an sp3 carbon, a new In(III) MOF has been obtained. The structure is described as thick layers with the bent geometry of the ligand leading to the formation of square-shaped channels, which run inside the framework layers. This microporous, thermally stable compound has been proved to be an efficient heterogeneous catalyst for acetalization of aldehydes. Differences in the catalytic activity when a compound with empty or filled channels is used demonstrate that the catalytic reactions take place inside the pores.

An Indium Layered MOF as Recyclable Lewis Acid Catalyst

Herein, a new aromatic carboxylate ligand, namely, 4-(dipyridin-2-yl)aminobenzoic acid (HL), has been designed and employed for the construction of a series of lanthanide complexes (Eu3+ = 1, Tb3+ = 2, and Gd3+ = 3). Complexes of 1 and 2 were structurally authenticated by single-crystal X-ray diffraction and were found to exist as infinite 1D coordination polymers with the general formulas {[Eu(L)3(H2O)2]}n (1) and {[Tb(L)3(H2O)].(H2O)}n (2). Both compounds crystallize in monoclinic space group C2/c. The photophysical properties demonstrated that the developed 4-(dipyridin-2-yl)aminobenzoate ligand is well suited for the sensitization of Tb3+ emission (Φoverall = 64%) thanks to the favorable position of the triplet state (3ππ*) of the ligand [the energy difference between the triplet state of the ligand and the excited state of Tb3+ (ΔE) = 3ππ* – 5D4 = 3197 cm–1], as investigated in the Gd3+ complex. On the other hand, the corresponding Eu3+ complex shows weak luminescence efficiency (Φoverall = 7%) due t...

Highly luminescent and thermally stable lanthanide coordination polymers designed from 4-(dipyridin-2-yl)aminobenzoate: efficient energy transfer from Tb3+ to Eu3+ in a mixed lanthanide coordination compound.

Hydrothermal synthesis of three new 3-D framework rare-earth mellitates

Remarkable enhancement and quenching of photo-luminescent emissions have been found in various mixed-lanthanide carboxylate polymers. In (Eu0.1:Tb99.9)2(2,2-biphenate)3(H2O)2 the Eu emission is comparable to the Eu homo-polymer, whilst the original Tb emission is reduced by ca. 80%. Either sensitized energy transfer or the reduction of self-quenching through dilution may play a dominant role.

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Quantifying enhanced photoluminescence in mixed-lanthanide carboxylate polymers: sensitizationversusreduction of self-quenching

Hydrothermal synthesis of indium tartrates: Structures of the chiral polymer [In(l-TAR)3−H2O] · 0.5H2O containing the tartrate trianion, and a microporous hybrid solid [In(OH)(d/l-TAR)2−] · 2H2O

Alvin W.-H. Siu

Papers

Hydrothermal synthesis of three new 3-D framework rare-earth mellitates

Quantifying enhanced photoluminescence in mixed-lanthanide carboxylate polymers: sensitizationversusreduction of self-quenching

Hydrothermal synthesis of indium tartrates: Structures of the chiral polymer [In(l-TAR)3−H2O] · 0.5H2O containing the tartrate trianion, and a microporous hybrid solid [In(OH)(d/l-TAR)2−] · 2H2O

Hydrothermal synthesis of [Ba3Cl2] [Sn3O4(OH)(8)], a compound with alternating ionic and covalent layers