Slow hole diffusion limits the efficiency of p-type dye-sensitized solar cells based on the P1 dye.

NiO electrodes are widely applied in p-type dye-sensitized solar cells (DSSCs) and photoelectrochemical cells, but due to excessive charge recombination, the efficiencies of these devices are still too low for commercial applications. To understand which factors induce charge recombination, we studied electrodes with a varying number of NiO layers in benchmark P1 p-DSSCs. We obtained the most efficient DSSCs with four layers of NiO (0.

Selective Electrochemical Oxygen Reduction to Hydrogen Peroxide by Confinement of Cobalt Porphyrins in a Metal-Organic Framework.

Sustainable alternatives for the energy intensive synthesis of HO are necessary. Molecular cobalt catalysts show potential but are typically restricted by undesired bimolecular pathways leading to the breakdown of both HO and the catalyst. The confinement of cobalt porphyrins in the PCN-224 metal-organic framework leads to an enhanced selectivity towards HO and stability of the catalyst.

Direct Probing of Vibrational Interactions in UiO-66 Polycrystalline Membranes with Femtosecond Two-Dimensional Infrared Spectroscopy.

UiO-66 is a benchmark metal-organic framework that holds great promise for the design of new functional materials. In this work, we perform two-dimensional infrared measurements on polycrystalline membranes of UiO-66 grown on c-sapphire substrates. We study the symmetric and antisymmetric stretch vibrations of the carboxylate groups of the terephthalate linker ions and find that these vibrations show a rapid energy exchange and a collective vibrational relaxation with a time constant of 1.

Correction: Role of additives and solvents in the synthesis of chiral isoreticular MOF-74 topologies.

Correction for 'Role of additives and solvents in the synthesis of chiral isoreticular MOF-74 topologies' by Andreea Gheorghe , , 2021, DOI: 10.1039/D1DT01945G.

Role of additives and solvents in the synthesis of chiral isoreticular MOF-74 topologies.

Chiral induction is a simple and inexpensive approach to synthesise chiral metal-organic frameworks, even when using achiral building-blocks. The challenge lies in selecting the proper chiral inductor. This can only be achieved upon understanding the mechanism behind the chirality transfer from the chiral guest to the achiral MOF.

Synthesis of Chiral MOF-74 Frameworks by Post-Synthetic Modification by Using an Amino Acid.

The synthesis of chiral metal-organic frameworks (MOFs) is highly relevant for asymmetric heterogenous catalysis, yet very challenging. Chiral MOFs with MOF-74 topology were synthesised by using post-synthetic modification with proline. Vibrational circular dichroism studies demonstrate that proline is the source of chirality.

Water-Ethanol and Methanol-Ethanol Separations Using in Situ Confined Polymer Chains in a Metal-Organic Framework.

This study presents a straightforward approach for the in situ polymerization of poly(-isopropylacrylamide) (PNIPAM) chains within the one-dimensional (1D) pores of the five-coordinated zinc-based metal-organic framework DMOF in order to obtain new MOF-based composites. The loading amount of PNIPAM within DMOF ⊃ PNIPAM composites can be tuned by changing the initial weight ratio between NIPAM, which is the monomer of PNIPAM, and DMOF. The guest PNIPAM chains in the composites block partially the 1D pores of DMOF, thus leading to a narrowed nanospace.

Tuning the supramolecular isomerism of MOF-74 by controlling the synthesis conditions.

Supramolecular isomerism of metal-organic frameworks (MOFs) is known for several MOF structures, having direct implications on the properties of these materials. Although the synthesis of MOF isomers is mainly serendipitous in nature, achieving controlled formation of a target framework is highly relevant for practical applications. This work discusses the influence of additives and synthesis conditions on the formation of porous isomers containing Zn as nodes and 2,5-dihydroxy-1,4-benzenedicarboxylate (dobdc) as a linker.

Efficient Separation of Ethanol-Methanol and Ethanol-Water Mixtures Using ZIF-8 Supported on a Hierarchical Porous Mixed-Oxide Substrate.

This work reports a new approach for the synthesis of a zeolitic imidazolate framework (ZIF-8) composite. It employs the direct growth of the crystalline ZIF-8 on a mixed-metal oxide support TiO-SiO (TSO), which mimics the porous structure of Populus nigra. Using the natural leaf as a template, the TSO support was prepared using a sol-gel method.

Coordination polymers from alkaline-earth nodes and pyrazine carboxylate linkers.

A new series of alkaline-earth-metal based coordination polymers were synthesized by using a pyrazine-2,5-dicarboxylic acid (2,5-H2pzdc) ligand under hydrothermal conditions. These compounds show a variety of structural topologies, reflecting the variable coordination geometries of the alkaline-earth ions as well as the key role of the metal precursor salts. Ca, Sr, and Ba give porous three-dimensional compounds, namely [Ca(2,5-pzdc)(H2O)2]·H2O (1), [Sr(2,5-pzdc)(H2O)4]·H2O (3), [Ba(2,5-pzdc)(H2O)4]·2H2O (4) and [Ba(2,5pzdc)(H2O)2] (5), that feature one-dimensional hydrophilic channels which are filled with water molecules.

Sustainable Separations of C -Hydrocarbons by Using Microporous Materials.

Petrochemical refineries must separate hydrocarbon mixtures on a large scale for the production of fuels and chemicals. Typically, these hydrocarbons are separated by distillation, which is extremely energy intensive. This high energy cost can be mitigated by developing materials that can enable efficient adsorptive separation.

Dual-mode humidity detection using a lanthanide-based metal-organic framework: towards multifunctional humidity sensors.

Combined photoluminescence and impedance spectroscopy studies show that a europium-based metal-organic framework behaves as a highly effective and reliable humidity sensor, enabling dual-mode humidity detection.

Water-Dispersible Silica-Coated Upconverting Liposomes: Can a Thin Silica Layer Protect TTA-UC against Oxygen Quenching?

Light upconversion by triplet-triplet annihilation (TTA-UC) in nanoparticles has received considerable attention for bioimaging and light activation of prodrugs. However, the mechanism of TTA-UC is inherently sensitive for quenching by molecular oxygen. A potential oxygen protection strategy is the coating of TTA-UC nanoparticles with a layer of oxygen-impermeable material.

A rational synthesis of hierarchically porous, N-doped carbon from Mg-based MOFs: understanding the link between nitrogen content and oxygen reduction electrocatalysis.

Controlled mixtures of novel Mg-based metal-organic frameworks (MOFs) were prepared, with H(+) or K(+) as counterions. A linear relation was found between synthesis pH and K/H ratio in the resultant mixture, establishing the tunability of the synthesis. Upon pyrolysis, these precursor mixtures yield nitrogen-doped, hierarchically porous carbons, which have good activity towards the oxygen reduction reaction (ORR) at pH 13.

Mixed-Lanthanoid Metal-Organic Framework for Ratiometric Cryogenic Temperature Sensing.

A ratiometric thermometer based on a mixed-metal Ln(III) metal-organic framework is reported that has good sensitivity in a wide temperature range from 4 to 290 K and a quantum yield of 22% at room temperature. The sensing mechanism in the europium-doped compound Tb0.95Eu0.

A novel one-dimensional chain built of vanadyl ions and pyrazine-2,5-dicarboxylate.

We present a new coordination polymer, {[VO(pzdc)(H2O)2] H2O}n, built from vanadyl and pyrazine-2,5-dicarboxylate (pzdc) ions. It consists of a one-dimensional chain of vanadyl ions linked by pzdc ions. The carboxylate groups show monodentate coordination, while the pyrazine ring is present both in non-coordinated and coordinated modes.

Highly selective water adsorption in a lanthanum metal-organic framework.

We present a new metal-organic framework (MOF) built from lanthanum and pyrazine-2,5-dicarboxylate (pyzdc) ions. This MOF, [La(pyzdc)1.5(H2O)2]⋅2 H2O, is microporous, with 1D channels that easily accommodate water molecules.

Synthesis, characterization and testing of a new V2O5/Al2O3-MgO catalyst for butane dehydrogenation and limonene oxidation.

We report the synthesis and characterization of new V2O5/Al2O3-MgO catalysts and their application in oxidative dehydrogenation and epoxidation reactions. The materials were prepared by wet impregnation under excess acid conditions. Anchoring of the desired species on the support occurs via an exchange reaction between the vanadium complex and surface hydroxyl groups.

Poly(vinylidene fluoride)/nickel nanocomposites from semicrystalline block copolymer precursors.

The fabrication of nanoporous poly(vinylidene fluoride) (PVDF) and PVDF/nickel nanocomposites from semicrystalline block copolymer precursors is reported. Polystyrene-block-poly(vinylidene fluoride)-block-polystyrene (PS-b-PVDF-b-PS) is prepared through functional benzoyl peroxide initiated polymerization of VDF, followed by atom transfer radical polymerization (ATRP) of styrene. The crystallization of PVDF plays a dominant role in the formation of the block copolymer structure, resulting in a spherulitic superstructure with an internal crystalline-amorphous lamellar nanostructure.

Mononuclear and dinuclear manganese compounds stabilized by supramolecular interactions.

New manganese compounds [Mn(HphpzMe)(2)(H(2)phpzMe)(HCO(2))] (1), [Mn(2)(phpzMe)(2)(HphpzMe)(2)(OCH(3))]·2CH(3)OH (2), Na{[Mn(HphpzPh)(phpzPh)(MeOH)(2)](2)}(HCO(2)) (3), [Mn(HphpzPh)(2)(EtOH)(2)]ClO(4)·2EtOH (4) and [Mn(HphpzPh)(2)N(3)] (5) were synthesized and characterized with various techniques. 1, 4 and 5 are mononuclear manganese(III) compounds, 2 is a mixed-valence dinuclear manganese(III/IV) compound, and 3 is a trinuclear compound containing two manganese(III) ions and a sodium(I) ion. A remarkable feature is the spontaneous formation of the formate ion as a result of the methanol or methoxide oxidation in compounds 1 and 3.

Structure and magnetism in Fe-Gd based dinuclear and chain systems. The interplay of weak exchange coupling and zero field splitting effects.

The synthesis and characterization of two Fe-Gd systems based on bpca(-) (Hbpca = bis(2-pyridilcarbonyl)amine) as bridging ligand is presented, taking the systems as a case study for structure-property correlations. Compound 1, [Fe(LS)(II)(μ-bpca)(2)Gd(NO(3))(2)(H(2)O)]NO(3)·2CH(3)NO(2), is a zigzag polymer, incorporating the diamagnetic low spin Fe(LS)(II) ion. The magnetism of 1 is entirely determined by the weak zero field splitting (ZFS) effect on the Gd(III) ion.

Rationalization of the lanthanide-ion-driven magnetic properties in a series of 4f-5d cyano-bridged chains.

Magnetic properties of new d-f cyanido-bridged 1D assemblies [RE(pzam)(3)(H(2)O)W(CN)(8)]·H(2)O (RE(III) = Gd, 1, Tb, 2, Dy, 3; pzam = pyrazine-2-carboxamide) were studied by temperature- and field-dependent magnetization measurements. No evidence for 3D interchain magnetic ordering is found above 2 K. Multiconfiguration ab initio calculations and subsequent modeling afforded simulation of the weak zero-field splitting effect in 1 and discussion of magnetic anisotropy in the f units of compounds 2 and 3.

Short-range correlations in d-f cyanido-bridged assemblies with XY and XY-Heisenberg anisotropy.

Two new d-f cyanido-bridged 1D assemblies [RE(pzam)(3)(H(2)O)Mo(CN)(8)]·H(2)O (RE = Sm(III), Er(III)) were synthesized and their magneto-structural properties have been studied by field-dependent magnetization and specific heat measurements at low temperatures (≥0.3 K). Below ≈ 10 K the ground state of both the Sm(III) and Er(III) ions is found to be a Kramers doublet with effective spin S = 1/2.

High nuclearity manganese(III) compounds containing phenol-pyrazole ligands: the influence of the ligand on the core geometry.

Three high-nuclearity manganese(III) clusters have been synthesized and characterized: [Mn₈(μ₄-O)₄(phpzH)₈(thf)₄] (1), [Mn₈(μ₄-O)₄(phpzH)₄(EtOH)₄]·2EtOH (2), and [Mn₆(μ₃-O)₄(μ₃-Br)₂(HphpzEt)₆(phpzEt)] (3). Compounds 1 and 2 contain a [Mn₈(μ₄-O₄)(phpzH)₈] core in which antiferromagnetic interactions between the manganese(III) ions are found. Compound 3 is a hexanuclear manganese(III) cluster in which weak ferromagnetic interactions appear to be operative.

Manganese(III) compounds with phenol-pyrazole based-ligands: impact of the co-ligand and the carboxylate ligand on the trinuclear core [Mn3(mu3-O)(phpzR)3(O2CR')n](1-n).

The reaction of H2phpzR (R = Me, Ph; H2phpzMe = 3(5)-(2-hydroxyphenyl)-5(3)-methylpyrazole and H2phpzPh = 3(5)-(2-hydroxyphenyl)-5(3)-phenylpyrazole) with Mn(O2CR').nH2O (R' = Me and Ph) and (nBu4N)MnO4 in ethanol (EtOH) affords three new manganese(III) compounds, [Mn3(mu3-O)(phpzMe)3(O2CMe)(EtOH)].EtOH (1), (nBu4N)[Mn3(mu3-O)(phpzMe)3(O2CPh)2] (2) and (nBu4N)[Mn3(mu3-O)(phpzPh)3(O2CPh)2] (3).