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1.
Angew Chem Int Ed Engl ; 59(3): 1018-1029, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31294885

RESUMO

Mechanochemical solvent-free reactions by milling, grinding or other types of mechanical action have emerged as a viable alternative to solution chemistry. Mechanochemistry offers not only a possibility to eliminate the need for bulk solvent use, and reduce the generation of waste, but it also unlocks the door to a different reaction environment in which synthetic strategies, reactions and molecules previously not accessible in solution, can be achieved. This Minireview examines the potential of mechanochemistry in chemical and materials synthesis, by providing a cross-section of the recent developments in using ball milling for the formation of molecules and materials based on covalent and coordination bonds.

2.
J Am Chem Soc ; 140(49): 16882-16887, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30462919

RESUMO

We report a strategy to synthesize highly emissive, photostable, microporous materials by solid-state entrapment of boron dipyrromethene (BODIPY) fluorophores in a metal-organic framework. Solvent-free mechanochemistry or accelerated aging enabled quantitative capture and dispersal of the PM605 dye within the ZIF-8 framework starting from inexpensive, commercial materials. While the design of emissive BODIPY solids is normally challenged by quenching in a densely packed environment, herein reported PM605@ZIF-8 materials show excellent emissive properties and to the best of our knowledge an unprecedented ∼10-fold enhancement of BODIPY photostability. Time-resolved and steady-state fluorescence studies of PM605@ZIF-8 show that interchromophore interactions are minimal at low dye loadings, but at higher ones lead to through-pore energy transfer between chromophores and to aggregate species.

3.
Molecules ; 22(1)2017 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-28106754

RESUMO

Controlling the formation of coordination bonds is pivotal to the development of a plethora of functional metal-organic materials, ranging from coordination polymers, metal-organic frameworks (MOFs) to metallodrugs. The interest in and commercialization of such materials has created a need for more efficient, environmentally-friendly routes for making coordination bonds. Solid-state coordination chemistry is a versatile greener alternative to conventional synthesis, offering quantitative yields, enhanced stoichiometric and topological selectivity, access to a wider range of precursors, as well as to molecules and materials not readily accessible in solution or solvothermally. With a focus on mechanochemical, thermochemical and "accelerated aging" approaches to coordination polymers, including pharmaceutically-relevant materials and microporous MOFs, this review highlights the recent advances in solid-state coordination chemistry and techniques for understanding the underlying reaction mechanisms.


Assuntos
Técnicas de Química Sintética/métodos , Complexos de Coordenação/síntese química , Polímeros/síntese química , Catálise , Química Verde , Metais/química , Estrutura Molecular
4.
J Am Chem Soc ; 137(7): 2476-9, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25668586

RESUMO

We describe the development of a mechanochemical approach for Ru-catalyzed olefin metathesis, including cross-metathesis and ring-closing metathesis. The method uses commercially available catalysts to achieve high-yielding, rapid, room-temperature metathesis of solid or liquid olefins on a multigram scale using either no or only a catalytic amount of a liquid.

5.
Angew Chem Int Ed Engl ; 53(29): 7471-4, 2014 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-24889776

RESUMO

Zeolitic imidazolate frameworks of zinc, cobalt, and cadmium, including the framework ZIF-8 commercially sold as Basolite Z1200, exhibit surprising sensitivity to carbon dioxide under mild conditions. The frameworks chemically react with CO2 in the presence of moisture or liquid water to form carbonates. This effect, which has been previously not reported in metal-organic framework chemistry, provides an explanation for conflicting reports on ZIF-8 stability to water and is of outstanding significance for evaluating the potential applications of metal-organic frameworks, especially for CO2 sequestration.

6.
Angew Chem Int Ed Engl ; 53(35): 9321-4, 2014 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-25044238

RESUMO

Reported herein is the mechanochemical synthesis of sulfonyl guanidines, a family of molecules which are relevant as pharmaceuticals and herbicides, by direct coupling of sulfonamides and aromatic or aliphatic carbodiimides. Attempts to conduct the coupling in solution have either failed or given very low conversions, thus demonstrating mechanochemistry as the necessary component for the discovery of this synthetic strategy.

7.
Chem Sci ; 13(12): 3424-3436, 2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35432883

RESUMO

Hybrid rocket propulsion can contribute to reduce launch costs by simplifying engine design and operation. Hypergolic propellants, i.e. igniting spontaneously and immediately upon contact between fuel and oxidizer, further simplify system integration by removing the need for an ignition system. Such hybrid engines could also replace currently popular hypergolic propulsion approaches based on extremely toxic and carcinogenic hydrazines. Here we present the first demonstration for the use of hypergolic metal-organic frameworks (HMOFs) as additives to trigger hypergolic ignition in conventional paraffin-based hybrid engine fuels. HMOFS are a recently introduced class of stable and safe hypergolic materials, used here as a platform to bring readily tunable ignition and combustion properties to hydrocarbon fuels. We present an experimental investigation of the ignition delay (ID, the time from first contact with an oxidizer to ignition) of blends of HMOFs with paraffin, using White Fuming Nitric Acid (WFNA) as the oxidizer. The majority of measured IDs are under 10 ms, significantly below the upper limit of 50 ms required for functional hypergolic propellant, and within the ultrafast ignition range. A theoretical analysis of the performance of HMOFs-containing fuels in a hybrid launcher engine scenario also reveals the effect of the HMOF mass fraction on the specific impulse (I sp) and density impulse (ρI sp). The use of HMOFs to produce paraffin-based hypergolic fuels results in a slight decrease of the I sp and ρI sp compared to that of pure paraffin, similar to the effect observed with Ammonia Borane (AB), a popular hypergolic additive. HMOFs however have a much higher thermal stability, allowing for convenient mixing with hot liquid paraffin, making the manufacturing processes simpler and safer compared to other hypergolic additives such as AB.

8.
Pharmaceutics ; 12(12)2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33255979

RESUMO

The discovery and development of effective analgesics is greatly lagging behind the steadily rising prevalence of chronic pain. Currently prescribed analgesics for chronic pain are lacking in efficacy mainly due to their narrowly-targeted mechanism of action. Driving neuronal hyperexcitability that underlies symptoms of chronic pain are multiple non-neuronal processes, among which are tissue hypoxia and oxidative stress. Here we demonstrate the design, synthesis, and activity of new multi-component bi-functional analgesic crystalline solids, co-crystals, and salts, based on pairing of vasodilatory anti-hypoxic drugs pentoxifylline, clonidine and linsidomine with antioxidant nutraceuticals protocatechuic acid, α-lipoic acid, and caffeic acid. After validation, chemical and structural characterization of these novel salts and co-crystals, topical formulations of the products were tested in a rat model of complex regional pain syndrome. Analgesic effects achieved with the salts and co-crystal exceeded the efficacy and/or potency of constituent compounds indicating that more effective, advanced analgesics can readily be developed by careful pairing of compounds that simultaneously target multiple neural and non-neural processes driving chronic pain.

9.
Chem Sci ; 11(8): 2141-2147, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34123303

RESUMO

We demonstrate a simple method for real-time monitoring of mechanochemical synthesis of metal-organic frameworks, by measuring changes in pressure of gas produced in the reaction. Using this manometric method to monitor the mechanosynthesis of the zeolitic imidazolate framework ZIF-8 from basic zinc carbonate reveals an intriguing feedback mechanism in which the initially formed ZIF-8 reacts with the CO2 byproduct to produce a complex metal carbonate phase, the structure of which is determined directly from powder X-ray diffraction data. We also show that the formation of the carbonate phase may be prevented by addition of excess ligand. The excess ligand can subsequently be removed by sublimation, and reused. This enables not only the synthesis but also the purification, as well as the activation of the MOF to be performed entirely without solvent.

10.
Chem Commun (Camb) ; 52(14): 3054-7, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26794225

RESUMO

We describe a simple, rapid methodology for the synthesis of water-stable iron oxide nanoparticles (IONPs) compatible with a variety of aqueous buffers, based on mechanochemical milling exchange of covalently bound surface ligands on pre-fabricated oleic acid-protected IONPs. Application of milling for IONP ligand exchange eliminates steps required for transforming hydrophobic into negatively charged, water-soluble superparamagnetic IONPs.

11.
Chem Commun (Camb) ; 51(43): 8924-7, 2015 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-25779369

RESUMO

While azolate anions have been extensively used as anionic linkers in framework design, we now demonstrate the synthesis of square-grid networks that utilise their cationic analogues, imidazolium ions, as linkers. The resulting imidazolium frameworks are direct hydrogen-bonded analogues of square-grid metal azolates and the first examples of an inverted polarity framework design based on anionic nodes and cationic linkers.

12.
Nat Commun ; 6: 6662, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25798542

RESUMO

Chemical and physical transformations by milling are attracting enormous interest for their ability to access new materials and clean reactivity, and are central to a number of core industries, from mineral processing to pharmaceutical manufacturing. While continuous mechanical stress during milling is thought to create an environment supporting nonconventional reactivity and exotic intermediates, such speculations have remained without proof. Here we use in situ, real-time powder X-ray diffraction monitoring to discover and capture a metastable, novel-topology intermediate of a mechanochemical transformation. Monitoring the mechanochemical synthesis of an archetypal metal-organic framework ZIF-8 by in situ powder X-ray diffraction reveals unexpected amorphization, and on further milling recrystallization into a non-porous material via a metastable intermediate based on a previously unreported topology, herein named katsenite (kat). The discovery of this phase and topology provides direct evidence that milling transformations can involve short-lived, structurally unusual phases not yet accessed by conventional chemistry.

13.
Chem Commun (Camb) ; 50(40): 5248-50, 2014 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-24256886

RESUMO

We demonstrate the first application of mechanochemistry to conduct the synthesis of sulfonyl-(thio)ureas, including known anti-diabetic drugs tolbutamide, chlorpropamide and glibenclamide, in good to excellent isolated yields by either stoichiometric base-assisted or copper-catalysed coupling of sulfonamides and iso(thio)cyanates.


Assuntos
Clorpropamida/síntese química , Cobre/química , Glibureto/síntese química , Hipoglicemiantes/síntese química , Isotiocianatos/química , Sulfonamidas/química , Tolbutamida/síntese química , Catálise , Estrutura Molecular
14.
Faraday Discuss ; 170: 203-21, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25408067

RESUMO

An experimental technique for in situ and real-time monitoring of mechanochemical reactions in a shaker ball mill was recently described, which utilises highly penetrating X-ray radiation available at the ID15B beamline of the European Synchrotron Radiation Facility. Herein, we describe the first attempts to perform such reaction monitoring in a quantitative fashion, by introducing an internal X-ray diffraction standard. The use of silicon as an internal standard resolved the issue with variations of the amount of the sample in the X-ray beam due to the non-uniform distribution of the sample in the reaction jar and allowed, via Rietveld analysis, the first quantitative estimate of the amorphous phase content in a mechanochemical reaction as it is being milled. We also highlight problems associated with the non-ideal mixing of the reaction mixture.


Assuntos
Imidazóis/química , Óxido de Zinco/química , Silício/química , Difração de Raios X
15.
Orphanet J Rare Dis ; 8: 11, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23316740

RESUMO

BACKGROUND: Many genetic diseases are due to defects in protein trafficking where the mutant protein is recognized by the quality control systems, retained in the endoplasmic reticulum (ER), and degraded by the proteasome. In many cases, the mutant protein retains function if it can be trafficked to its proper cellular location. We have identified structurally diverse correctors that restore the trafficking and function of the most common mutation causing cystic fibrosis, F508del-CFTR. Most of these correctors do not act directly as ligands of CFTR, but indirectly on other pathways to promote folding and correction. We hypothesize that these proteostasis regulators may also correct other protein trafficking diseases. METHODS: To test our hypothesis, we used stable cell lines or transient transfection to express 2 well-studied trafficking disease mutations in each of 3 different proteins: the arginine-vasopressin receptor 2 (AVPR2, also known as V2R), the human ether-a-go-go-related gene (KCNH2, also known as hERG), and finally the sulfonylurea receptor 1 (ABCC8, also known as SUR1). We treated cells expressing these mutant proteins with 9 structurally diverse F508del-CFTR correctors that function through different cellular mechanisms and assessed whether correction occurred via immunoblotting and functional assays. Results were deemed significantly different from controls by a one-way ANOVA (p < 0.05). RESULTS: Here we show that F508del-CFTR correctors RDR1, KM60 and KM57 also correct some mutant alleles of other protein trafficking diseases. We also show that one corrector, the cardiac glycoside ouabain, was found to alter the glycosylation of all mutant alleles tested. CONCLUSIONS: Correctors of F508del-CFTR trafficking might have broader applications to other protein trafficking diseases.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Fibrose Cística/terapia , Western Blotting , AMP Cíclico/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Células HeLa , Humanos , Técnicas In Vitro , Proteínas Mutantes/genética , Técnicas de Patch-Clamp , Transporte Proteico , Rubídio/metabolismo
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