I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[22411]
Abstract: We report the two-step synthesis of a heterobimetallic oxamato-based metal-organic framework (MOF). First, we prepared an oxamato functionalized carbazole-based dinuclear copper(II) complex, K4{Cu2(carbox)2]}·8H2O, where the carbozale linkers exhibited an uncommon substitution pattern, carbox = N,N’-1,6-carbazolebis(oxamate). Then, this building block was used as a metalloligand toward manganese(II) metal ions to assemble a neutral three-dimensional (3 D) MOF with formula [Mn2Cu2(carbox)2(H2O)4]·6CH3OH·2H2O (1) and single-crystal X-ray diffraction determined the structure. The resulting network constitutes one of the few examples of oxamato-based 3 D MOF.
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Sep 2022
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[28808]
Open Access
Abstract: Considering the wide interest in (benz)imidazolium-based drugs, we here report our study on a benzimidazolium-based organic cage as potential antimicrobial and antifungal agent. Cytotoxicity studies on a human derived cell line, SH-SY5Y, showed that the cage is not cytotoxic at all at the investigated concentrations. Anion binding studies demonstrated that the cage can bind anions (chloride and nitrate, in particular) both in organic solvent and 20%v D2O/CD3CN mixture. The cage was also tested as anionophore, showing a weak but measurable transport of chloride and nitrate across LUVs vesicles. Nonetheless, the compounds have antimicrobial activity towards Staphylococcus aureus (Gram-positive bacteria). This is probably the first organic cage studied as anionophore and antimicrobial agent.
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Aug 2022
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[22411]
Abstract: The preparation of novel efficient catalysts─that could be applicable in industrially important chemical processes─has attracted great interest. Small subnanometer metal clusters can exhibit outstanding catalytic capabilities, and thus, research efforts have been devoted, recently, to synthesize novel catalysts bearing such active sites. Here, we report the gram-scale preparation of Ag20 subnanometer clusters within the channels of a highly crystalline three-dimensional anionic metal–organic framework, with the formula [Ag20]@AgI2NaI2{NiII4[CuII2(Me3mpba)2]3}·48H2O [Me3mpba4– = N,N′-2,4,6-trimethyl-1,3-phenylenebis(oxamate)]. The resulting crystalline solid catalyst─fully characterized with the help of single-crystal X-ray diffraction─exhibits high catalytic activity for the catalytic Buchner ring expansion reaction.
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Jul 2022
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[22411]
Open Access
Abstract: Amides and esters are prevalent chemicals in Nature, industry and academic laboratories. Thus, it is not surprising that a plethora of synthetic methods for these compounds has been developed along the years. However, these methods are not 100% atom economical and generally require harsh reagents or reaction conditions. Here we show a “spring–loaded”, 100% atom–efficient amidation and esterification protocol which consists in the ring opening of cyclopropenones with amines or alcohols. Some alkyl amines react spontaneously at room temperature in a variety of solvents and reaction conditions, including water at different pHs, while other alkyl amines, aromatic amines and alcohols react in the presence of catalytic amounts of simple Cu2+ salts or solids. A modular reactivity pattern (alkyl amines >> alkyl alcohols >> phenols >> aromatic amines) enables to design orthogonal and one–pot reactions on well–defined catalytic Multimetal–Organic Frameworks (M–MOFs, M= Cu, Ni, Pd), to easily functionalize the resulting cinnamides and cinnamic esters to more complex molecules. The strong resemblance of the amidation and esterification reaction conditions here reported with the copper–catalyzed azide–alkyne cycloaddition (CuAAC) allows to define this fast, clean and flexible protocol as a click reaction.
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Apr 2022
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[22411]
Abstract: Extremely high electrophilic metal complexes, composed by a metal cation and very electron poor σ–donor ancillary ligands, are expected to be privileged catalysts for oxidation reactions in organic chemistry. However, their low lifetime prevents any use in catalysis. Here we show the synthesis of fluorinated pyridine–Pd 2+ coordinate cages within the channels of an anionic tridimensional metal organic framework (MOF), and their use as efficient metal catalysts for the aerobic oxidation of aliphatic alcohols to carboxylic acids without any additive. Mechanistic studies strongly support that the MOF–stabilized coordination cage with perfluorinated ligands unleashes the full electrophilic potential of Pd 2+ to dehydrogenate primary alcohols, without any base, and also to activate O 2 for the radical oxidation to the aldehyde intermediate. This study opens the door to design catalytic perfluorinated complexes for challenging organic transformations, where an extremely high electrophilic metal site is required.
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Dec 2021
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[18768, 22411]
Open Access
Abstract: Human society is facing—among other environmental threats—an enormous challenge due to human activities. The extensive use of high-tech devices and electronics equipment in the daily life makes, among others, rare-earth elements (REEs) recovery from secondary sources highly required. Here, a novel bioMOF-based single-walled carbon nanotube buckypaper (SWCNTBP) is presented as a new and efficient composite material (BioMOF@SWCNT-BP). The flexible and highly crystalline metal–organic framework (MOF), prepared from the natural amino acid L-threonine, has been homogeneously dispersed within the tangled net of a self-standing SWCNT-BP for lanthanides recovery from water. This MOF-carbon-based membrane exhibits high efficiency, either in static or dynamic regimes, in the recovery of lanthanides from aqueous streams outperforming the state-of-the-art. The capture performances of BPs are successfully improved after incorporation of such MOF featuring hexagonal functional channels decorated with the threonine amino acid residues, pointing toward the accessible void spaces, which boosts the capture properties of the final membrane, providing the adaptable functional environment to interact with lanthanides. This material's preparation presents also a potential for large-scale applications with a potential benefit on natural aquatic ecosystems as well. It is highly demanded because REEs from non-recycled waste materials are potential pollutants for surface waters.
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Aug 2021
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[22411, 25759]
Abstract: Circumventing the impact of agrochemicals on aquatic environments has become a necessity for health and ecological reasons. Herein, we report the use of a family of five eco-friendly water-stable isoreticular metal–organic frameworks (MOFs), prepared from amino acids, as adsorbents for the removal of neonicotinoid insecticides (thiamethoxam, clothianidin, imidacloprid, acetamiprid, and thiacloprid) from water. Among them, the three MOFs containing thioether-based residues show remarkable removal efficiency. In particular, the novel multivariate MOF {SrIICuII6[(S,S)-methox]1.5[(S,S)-Mecysmox]1.50(OH)2(H2O)}·36H2O (5), featuring narrow functional channels decorated with both −CH2SCH3 and −CH2CH2SCH3 thioalkyl chains—from l-methionine and l-methylcysteine amino acid-derived ligands, respectively—stands out and exhibits the higher removal efficiency, being capable to capture 100% of acetamiprid and thiacloprid in a single capture step under dynamic solid-phase extraction conditions—less than 30 s. Such unusual combination of outstanding efficiency, high stability in environmental conditions, and low-cost straightforward synthesis in 5 places this material among the most attractive adsorbents reported for the removal of this type of contaminants.
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Jun 2021
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I19-Small Molecule Single Crystal Diffraction
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Estefanía
Tiburcio
,
Rossella
Greco
,
Marta
Mon
,
Jordi
Ballesteros-Soberanas
,
Jesus
Ferrando-Soria
,
Juan-Carlos
Hernandez-Garrido
,
Judit
Oliver-Meseguer
,
Carlo
Marini
,
Mercedes
Boronat
,
Donatella
Armentano
,
Antonio
Leyva-Perez
,
Emilio
Pardo
,
Miguel
López-Haro
Diamond Proposal Number(s):
[18768, 22411]
Abstract: Metal single-atom catalysts (SACs) promise great rewards in terms of
metal atom efficiency. However, the requirement of particular conditions and
supports for their synthesis, together with the need of solvents and additives for
catalytic implementation, often precludes their use under industrially viable
conditions. Here, we show that palladium single atoms are spontaneously formed
after dissolving tiny amounts of palladium salts in neat benzyl alcohols, to catalyze
their direct aerobic oxidation to benzoic acids without ligands, additives, or solvents.
With this result in hand, the gram-scale preparation and stabilization of Pd SACs
within the functional channels of a novel methyl-cysteine-based metal−organic
framework (MOF) was accomplished, to give a robust and crystalline solid catalyst
fully characterized with the help of single-crystal X-ray diffraction (SCXRD). These
results illustrate the advantages of metal speciation in ligand-free homogeneous organic reactions and the translation into solid
catalysts for potential industrial implementation.
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Feb 2021
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I19-Small Molecule Single Crystal Diffraction
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Rosaria
Bruno
,
Marta
Mon
,
Paula
Escamilla
,
Jesus
Ferrando‐soria
,
Elisa
Esposito
,
Alessio
Fuoco
,
Marcello
Monteleone
,
Johannes C.
Jansen
,
Rosangela
Elliani
,
Antonio
Tagarelli
,
Donatella
Armentano
,
Emilio
Pardo
Diamond Proposal Number(s):
[22411]
Abstract: The mercury removal efficiency of a novel metal-organic framework (MOF)
derived from the amino acid S-methyl-L-cysteine is presented and the process
is characterized by single-crystal X-ray crystallography. A feasibility study is
further presented on the performance of this MOF—and also that of another
MOF derived from the amino acid L-methionine—when used as the sorbent
in mixed matrix membranes (MMMs). These MOF-based MMMs exhibit
high efficiency and selectivity—in both static and dynamic regimes—in the
removal of Hg2+ from aqueous environments, due to the high density of thioalkyl
groups decorating MOF channels. Both MMMs are capable to reduce
different concentration of the pollutant to acceptable limits for drinking water
(<2 parts per billion). In addition, a novel device, consisting of the recirculation
and adsorption of contaminated solutions through the MOF–MMMs,
is designed and successfully explored in the selective capture of Hg2+. Thus,
filtration of Hg2+ solutions with multiple passes through the permeation
cell shows a gradual decrease of the pollutant concentration. These results
suggest that MOF-based MMMs can be implemented in water remediation,
helping to reduce either contaminants from accidental unauthorized or deliberate
metal industrial dumping and to ensure access for clean and potable
freshwater.
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Nov 2020
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[18768]
Abstract: The low‐temperature water‐gas shift reaction (WGSR, CO + H 2 O ⇔ H 2 + CO 2 ) is considered a very promising reaction –candidate for fuel cells– despite an efficient and robust catalyst is still desirable. One of the more prominent catalysts for this reaction is based on single Pt atoms (Pt 1 ) on different supports, which are supposed to manifold the reaction by the accepted mechanism for the general WGSR, i.e. by addition of one H 2 O molecule to CO, with generation of CO 2 and H 2 . Here we show, experimentally, that not one but two H 2 O molecules are added to CO on the Pt 1 catalyst, as assessed by a combination of reactivity experiments with soluble Pt catalysts, kinetic and spectroscopic measurements, and finally by in‐operando single crystal X‐ray diffraction on a Pt 1 ‐MOF, to visualize the formation of the hemiacetal intermediate on the solid catalytic site. These results confirm our previous DFT predictions and provide a paradigmatic shift in the assumed mechanism of the WGSR, which may open the debate if two H 2 O molecules are recurrently added during the WGSR, not only for Pt 1 catalysts but also for other metal catalysts.
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Nov 2020
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