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The employment of fluorescence sensors provides a platform for rapid and efficient in-field detection of nitroaromatic compounds and is gaining increasing research ground. Herein, we report the synthesis and characterisation of three new fluorescent Al(III) MOFs, structurally analogous to MIL-53, with the assigned formula {Al(OH)(bdc)1−n(L-1)n}·xsolv (bdc2− = terephthalate; L-1 = 2-((benzyl)amino)-terephthalate). L-1 is a strongly fluorescent dicarboxylic ligand with a pendant π-electron rich aromatic group suitable for donor–acceptor interactions with electron-deficient nitroaromatic guests. Our MOFs show strong fluorescence quenching upon exposure to vapours of nitrobenzene, 1,3-dinitrobenzene, 4-nitrotoluene, and 2,4-dinitrotoluene. Additionally, we prepare and study MOF-polymer composites in the form of thin films that are strongly quenched in the presence of nitrobenzene vapours. [ABSTRACT FROM AUTHOR]

Targeting heterostructures with modulated electronic structures and efficient charge carrier separation and mobility is an effective strategy to improve photocatalytic performance. In this study, we report the synthesis of 2D/3D hybrid heterostructures comprising P-doped graphitic carbon nitride (g-C3N4) nanosheets (ca. 50–60 nm in lateral size) and small-sized Ni2P nanoparticles (ca. 10–12 nm in diameter) and demonstrate their prominent activity in the photocatalytic reduction of Cr(VI). Utilizing a combination of spectroscopic and electrochemical characterization techniques, we unveil the reasons behind the distinct photochemical performance of these materials. We show that Ni2P modification and P doping of the g-C3N4 effectively improve the charge-carrier transportation and spatial separation through the interface of Ni2P/P-doped g-C3N4 junctions. As a result, the catalyst containing 15 wt.% Ni2P exhibits superior photocatalytic activity in the detoxification of Cr(VI)-contaminated effluents under UV-visible light illumination, presenting an apparent quantum yield (QY) of 12.5% at 410 nm, notably without the use of sacrificial additives. This study marks a forward step in understanding and fabricating cost-effective photocatalysts for photochemical applications. [ABSTRACT FROM AUTHOR]

Environmental pollution has been a reality for many decades, with its contamination intensifying daily due to rapid urbanization and the ever-increasing world population. Dyes, and especially synthetic ones, constitute a category of pollutants that not only affect the quality of water but also exhibit high toxicity toward living organisms. This study was thoroughly planned to explore the removal of two toxic dyes, namely the methylene blue (MB) and methyl orange (MO) compounds from contaminated aqueous media. For this purpose, we designed and synthesized two new composite materials based on ammonium-functionalized Zr4+ MOF (MOR-1 or UiO-66-NH3+) and naturally occurring sorbents, such as bentonite and clinoptilolite. The composite materials displayed exceptional sorption capability toward both MB+ and MO− ions. A key finding of this study was the high efficiency of the composite materials to simultaneously remove MB+ and MO− under continuous flow conditions, also showing regeneration capability and reusability, thus providing an alternative to well-known mixed bed resins. [ABSTRACT FROM AUTHOR]

In the present study we provide the sorption properties of four 8-connected Zr4+ MOFs with the general formula H16[Zr6O16(RNH-BDC)4]·solvent (RNH-BDC2− = 2-alkyl-amine-terephthalate; R = ethyl-, ET-MOF; R = propyl-, PROP-MOF; R = isobutyl-, SBUT-MOF; R = n-butyl, BUT-MOF) towards toxic Cr(VI) and radionuclide-related ReO4− oxoanions. These MOFs represent superior sorbents for the removal of oxoanionic species, in terms of kinetics, sorption isotherms, selectivity and regeneration/reusability. The excellent sorption capability of the MOFs is due to a combination of surface and intra-framework sorption phenomena. The latter process proceeds via replacement of terminal water/hydroxyl ligands from the Zr6 clusters and subsequent binding of oxonanions to the Zr4+ centers, a fact that was proved via Rietveld PXRD analysis for the anion-loaded BUT-MOF. Importantly, BUT-MOF demonstrated an exceptional sorption capacity for Cr2O72− (505 mg g−1) and was further utilized in a sorption column in the form of MOF/calcium alginate beads, displaying remarkable removal efficiency towards industrial (chrome-plating) wastewater. Furthermore, the luminescence Cr(VI) sensing properties of BUT-MOF were explored in detail, presenting high sensitivity (detection limits as low as 9 ppb) and selectivity for these species against various competitive anions. [ABSTRACT FROM AUTHOR]

Reaction between Mn(NO3)2 ⋅ 6H2O, Zn(NO3)2 ⋅ 6H2O, 1,3,5‐tri(2‐hydroxyethyl)‐1,3,5‐triazacyclohexane (H3L) and pyrazole in MeOH under basic conditions leads to the formation of the decanuclear complex [MnIII6MnII2ZnII2(L)2(pyr)4O4(OH)4(NO3)2 (MeOH)2(H2O)4](NO3)2 ⋅ Η2Ο (1 ⋅ Η2Ο). The metallic core of the cationic cluster consists of a central hexagonal‐bipyramidal {MnIII4MnII2ZnII2} unit connected to two peripheral trivalent Mn centers arranged in a "trans" fashion, with one MnIII center lying above and one MnIII center below the hexagonal plane. Replacing Mn(NO3)2 ⋅ 6H2O with MnBr2 ⋅ 4H2O and repeating the same reaction leads to the formation of the related, neutral decanuclear complex [MnIII6MnII2ZnII2(L)2(pyr)4O4(OH)4Br4(H2O)2] (2), displaying the same metallic core as 1. Addition of THF to the reaction mixture that produces (2) affords the neutral dodecanuclear complex [MnIII6MnII2ZnII4(L)2(pyr)6O4(OH)4Br6(H2O)4] ⋅ 8THF (3 ⋅ 8THF), whose metallic skeleton retains the central hexagonal‐bipyramidal {MnIII4MnII2ZnII2} unit found in 1 and 2 but is now connected to two peripheral {MnIIIZnII} units. Magnetic susceptibility and magnetization measurements carried out in the T=2–300 K temperature range and in fields up to B=7.0 T for all three complexes reveal dominant antiferromagnetic exchange interactions. [ABSTRACT FROM AUTHOR]

The use of terephthalate ligands with CnH2n+1NH-chains (n ≥ 6) led to the isolation of the first examples of Zr4+-terephthalate MOFs with 6-connected frameworks. The material with hexyl-amino functional groups has been proved to be an exceptional sorbent for the removal of As(III / V) toxic species from aqueous media, whereas MOFs with heptyl to dodecyl-amino moieties are superhydrophobic with promising oil–water separation properties. [ABSTRACT FROM AUTHOR]

An amino acid containing octanuclear heterometallic {[Mn III3 Ca]2} cluster has been synthesized, alongside a structurally-related trigonal prismatic [Mn III6 Ca]2+ cage. [ABSTRACT FROM AUTHOR]

Understanding of the band-edge electronic structure and charge-transfer dynamics in size-confined nanostructures is vital in designing new materials for energy conversion applications, including green hydrogen production, decomposition of organic pollutants and solar cells. In this study, a series of mesoporous materials comprising continuous networks of linked zinc indium sulfide (ZnIn 2 S 4 ) nanocrystals with a tunable diameter (ranging from 4 to 12 nm) is reported. These nanomaterials demonstrate intriguing size-dependent electronic properties, charge-transfer kinetics and photocatalytic behaviors. Our extensive characterizations uncover strong size effects on the catalytic activity of constituent ZnIn 2 S 4 nanocrystals in the photochemical hydrogen evolution reaction. As an outcome, the optimized single-component ZnIn 2 S 4 mesostructure produces hydrogen at a 7.8 mmol g cat -1 h -1 release rate under ultraviolet (UV)-visible light irradiation associated with an apparent quantum yield (AQY) of 17.2% at 420 ± 10 nm, far surpassing its microstructured counterpart by a factor of 10.7×. These findings provide a valuable perspective for the rational design of semiconductor nanostructures through synthetic engineering, aiming at the development of high-performance catalysts for zero-carbon energy-related applications., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Photocatalytic water splitting for hydrogen generation is an appealing means of sustainable solar energy storage. In the past few years, mesoporous semiconductors have been at the forefront of investigations in low-cost chemical fuel production and energy conversion technologies. Mesoporosity combined with the tunable electronic properties of semiconducting nanocrystals offers the desired large accessible surface and electronic connectivity throughout the framework, thus enhancing photocatalytic activity. In this work, we present the construction of rationally designed 3D mesoporous networks of Co 2 P-modified CdIn 2 S 4 nanoscale crystals (ca. 5-6 nm in size) through an effective soft-templating synthetic route and demonstrate their impressive performance for visible-light-irradiated catalytic hydrogen production. Spectroscopic characterizations combined with electrochemical studies unravel the multipathway electron transfer dynamics across the interface of Co 2 P/CdIn 2 S 4 Mott-Schottky nanoheterojunctions and shed light on their impact on the photocatalytic hydrogen evolution chemistry. The strong Mott-Schottky interaction occurring at the heterointerface can regulate the charge transport toward greatly improved hydrogen evolution performance. The hybrid catalyst with 10 wt % Co 2 P content unveils a H 2 evolution rate of 20.9 mmol g cat -1 h -1 under visible light irradiation with an apparent quantum efficiency (AQE) up to 56.1% at 420 nm, which is among the highest reported activities. The understanding of interfacial charge-transfer mechanism could provide valuable insights into the rational development of highly efficient catalysts for clean energy applications., Competing Interests: The authors declare no competing financial interest., (© 2024 American Chemical Society.)

In the present study we provide the sorption properties of four 8-connected Zr 4+ MOFs with the general formula H 16 [Zr 6 O 16 (RNH-BDC) 4 ]·solvent (RNH-BDC 2- = 2-alkyl-amine-terephthalate; R = ethyl-, ET-MOF ; R = propyl-, PROP-MOF ; R = isobutyl-, SBUT-MOF ; R = n -butyl, BUT-MOF ) towards toxic Cr(VI) and radionuclide-related ReO 4 - oxoanions. These MOFs represent superior sorbents for the removal of oxoanionic species, in terms of kinetics, sorption isotherms, selectivity and regeneration/reusability. The excellent sorption capability of the MOFs is due to a combination of surface and intra-framework sorption phenomena. The latter process proceeds via replacement of terminal water/hydroxyl ligands from the Zr 6 clusters and subsequent binding of oxonanions to the Zr 4+ centers, a fact that was proved via Rietveld PXRD analysis for the anion-loaded BUT-MOF . Importantly, BUT-MOF demonstrated an exceptional sorption capacity for Cr 2 O 7 2- (505 mg g -1 ) and was further utilized in a sorption column in the form of MOF/calcium alginate beads, displaying remarkable removal efficiency towards industrial (chrome-plating) wastewater. Furthermore, the luminescence Cr(VI) sensing properties of BUT-MOF were explored in detail, presenting high sensitivity (detection limits as low as 9 ppb) and selectivity for these species against various competitive anions.

The use of terephthalate ligands with C n H 2 n +1 NH-chains ( n ≥ 6) led to the isolation of the first examples of Zr 4+ -terephthalate MOFs with 6-connected frameworks. The material with hexyl-amino functional groups has been proved to be an exceptional sorbent for the removal of As(III/V) toxic species from aqueous media, whereas MOFs with heptyl to dodecyl-amino moieties are superhydrophobic with promising oil-water separation properties.

An amino acid containing octanuclear heterometallic {[MnCa] 2 } cluster has been synthesized, alongside a structurally-related trigonal prismatic [MnCa] 2+ cage.