295 research outputs found
Multifunctional metal-organic frameworks : from academia to industrial applications
After three decades of intense and fundamental research on metal-organic frameworks (MOFs), is there anything left to say or to explain? The synthesis and properties of MOFs have already been comprehensively described elsewhere. It is time, however, to prove the nature of their true usability: technological applications based on these extended materials require development and implementation as a natural consequence of the up-to-known intensive research focused on their design and preparation. The current large number of reviews on MOFs emphasizes practical strategies to develop novel networks with varied crystal size, shape and topology, being mainly devoted to academic concerns. The present survey intends to push the boundaries and summarise the state-of-the-art on the preparation of promising (multi) functional MOFs in worldwide laboratories and their use as materials for industrial implementation. This review starts, on the one hand, to describe several tools and striking examples of remarkable and recent (multi) functional MOFs exhibiting outstanding properties (e.g., in gas adsorption and separation, selective sorption of harmful compounds, heterogeneous catalysis, luminescent and corrosion protectants). On the other hand, and in a second part, it intends to use these examples of MOFs to incite scientists to move towards the transference of knowledge from the laboratories to the industry. Within this context, we exhaustively review the many efforts of several worldwide commercial companies to bring functional MOFs towards the daily use, analysing the various patents and applications reported to date. Overall, this review goes from the very basic concepts of functional MOF engineering and preparation ending up in their industrial production on a large scale and direct applications in society
Poly[[μ2-aqua-tetraaquahexakis(μ4-naphthalene-2,6-dicarboxylato)tetraholmium(III)] 1.75-hydrate]
In the title compound, {[Ho4(C12H6O4)6(H2O)5]·1.75H2O}n, which is isostructural with its Tb3+- and Eu3+-containing analogues, there are four crystallographically independent Ho3+ centres, each exhibiting a highly distorted HoO8 bicapped trigonal-prismatic coordination environment. Adjacent polyhedra are interconnected via the carboxylate groups and one μ2-bridging water molecule, forming one-dimensional chains propagating along [100]. The naphthalene-2,6-dicarboxylate ligands further interconnect these chains into a three-dimensional framework, which has zigzag channels housing the water molecules. Two naphthalene-2,6-dicarboxylate bridging ligands have their centroids located on crystallographic centres of inversion. One water O atom has a fixed site occupancy factor of 0.75
Redetermination at 180 K of a layered lanthanide–organic framework
The asymmetric unit of the title compound, poly[(μ4-{[bis(hydrogen phosphonatomethyl)azaniumyl]methyl}phosphonato)lanthanum(III)], [La(C3H9NO9P3)]n, comprises an La3+ center and a H3nmp3− anion (where H3nmp3− is a residue of partially deprotonated nitrilotris(methylenephosphonic acid), namely {[bis(hydrogen phosphonatomethyl)azaniumyl]methyl}phosphonate). This study concerns a structural redetermination using single-crystal X-ray diffraction data, collected at the low temperature of 180 K, of a recently investigated material whose structural details have been proposed from powder X-ray diffraction studies [Silva et al. (2011 ▶). J. Am. Chem. Soc.
133, 15120–15138]. The main difference between the two models rests on the position of the H atoms. While two H atoms were modeled as attached to the same phosphonate group in the powder determination, in the current model, the same H atoms are instead distributed among two of these groups. The sample studied was an inversion twin
Influence of the alkali metal cation on the fragmentation of monensin in ESI-MS/MS
The MS/MS fragmentation of the alkali metal complexes of monensin A are studied. The increase in alkali metal ionic radii decreases the ability of the Grob-Wharton fragmentation mechanism to occur and reduces the overall degree of fragmentation. Conversely, the electronegativity of the metal cation is related to the number of fragment ions observed.O presente trabalho relata os estudos de fragmentação por espectrometria de massas seqüencial de complexos formados pela monensina A e uma série de metais alcalinos. Foi observado que o aumento do raio iônico do metal alcalino levou a uma diminuição do mecanismo de fragmentação do tipo Grob-Wharton e ao grau de fragmentação. Por outro lado, a maior eletronegatividade mostrou estar relacionada ao número de fragmentos observados
4,4′-Di-tert-butyl-2,2′-dipyridinium dichloride
In the title compound, C18H26N2
2+·2Cl−, the complete dication is generated by crystallographic inversion symmetry; both N atoms are protonated and engaged in strong and highly directional N—H⋯Cl hydrogen bonds. Additional weak C—H⋯Cl contacts promote the formation of a tape along ca. [110]. The crystal structure can be described by the parallel packing of these tapes. The crystal studied was a non-merohedral twin with twin law [−1 0 0, 0 −1 0, −0.887 0.179 1] and the final BASF parameter refining to 0.026 (2)
Robocode: A Instrumentalização do Ensino da Matemática por meio de uma Batalha entre Robôs Virtuais
O brasileiro apresenta baixa aprendizagem no ensino fundamental em matemática. Como ilustração pode-se citar que daqueles que estão no 9o ano, 63.11% têm nível insuficiente de proficiência na matéria, segundo Mariz [2018], considerando relatório 2017 do Sistema de Avaliação da Educação Básica, gerenciado por autarquia do Ministério da Educação do Brasil. Logo, é preciso engendrar esforços para superação deste quadro, o qual, segundo a citada pesquisa, é de estagnação há quase 10 anos; e neste trabalho sugere-se a adoção de recursos educativos inovadores e motivadores. Considerando que as Tecnologias de Informação e Comunicação permeiam a vida das crianças e dos jovens brasileiros, um possível recurso são os jogos digitais, os quais motivam e podem se destacar como recurso de educação. Dentre os games, neste trabalho evidencia-se o Robocode, jogo de estratégia, desenvolvido para ensino de programação, por meio de batalha entre robôs virtuais, que desperta interesse dos utilizadores, e possibilita também, a partir da visualização da dinâmica das disputas, explorar, observar e aprender matemática. Assim surge a ideia de capacitar professores de matemática a usarem Robocode com o objetivo de explorar o jogo sob uma perspectiva matemática
Robocode: A Instrumentalização do Ensino da Matemática por meio de uma Batalha entre Robôs Virtuais
O brasileiro apresenta baixa aprendizagem no ensino fundamental em matemática. Como ilustração pode-se citar que daqueles que estão no 9o ano, 63.11% têm nível insuficiente de proficiência na matéria, segundo Mariz [2018], considerando relatório 2017 do Sistema de Avaliação da Educação Básica, gerenciado por autarquia do Ministério da Educação do Brasil. Logo, é preciso engendrar esforços para superação deste quadro, o qual, segundo a citada pesquisa, é de estagnação há quase 10 anos; e neste trabalho sugere-se a adoção de recursos educativos inovadores e motivadores. Considerando que as Tecnologias de Informação e Comunicação permeiam a vida das crianças e dos jovens brasileiros, um possível recurso são os jogos digitais, os quais motivam e podem se destacar como recurso de educação. Dentre os games, neste trabalho evidencia-se o Robocode, jogo de estratégia, desenvolvido para ensino de programação, por meio de batalha entre robôs virtuais, que desperta interesse dos utilizadores, e possibilita também, a partir da visualização da dinâmica das disputas, explorar, observar e aprender matemática. Assim surge a ideia de capacitar professores de matemática a usarem Robocode com o objetivo de explorar o jogo sob uma perspectiva matemática
(R)-(1-Ammoniopropyl)phosphonate
The title compound, C3H10NO3P, crystallizes in its zwitterionic form, H3N+CH(C2H5)PO(O−)(OH), with the asymmetric unit being composed by two of such entities (Z′ = 2). The crystal packing leads to a sequence of hydrophobic and hydrophilic layers. While the hydrophobic layer comprises the aliphatic substituent groups, the hydrophilic one is held together by a series of strong and rather directional N+—H⋯O and O—H⋯O hydrogen bonds
Decaaquadioxidobis[μ3-N-(phosphonatomethyl)iminodiacetato]dizinc(II)divanadium(IV) dihydrate
The title compound, [Zn2V2(C5H6NO7P)2O2(H2O)10]·2H2O, contains a [V2O2(pmida)2]4− dimeric anionic unit [where H4pmida is N-(phosphonomethyl)iminodiacetic acid] lying on a centre of symmetry which is exo-coordinated via the two deprotonated phosphonate groups to two Zn2+ cations, with the coordination environment of Zn completed by five water molecules. The crystal packing is mediated by an extensive network of strong and highly directional O—H⋯O hydrogen bonds involving the water molecules (coordinated and uncoordinated) and the functional groups of pmida4−, leading to a three-dimensional supramolecular network
catena-[1,3-diammoniopropane di-mu2-hydroxodi-mu4-phosphato-trioxotrivanadium dihydrate]: a redetermination at 180 (2) K
The crystal structure of the title compound, (C3H12N2)-
[V3O3(OH)2(PO4)2] 2H2O, has been reported by Soghomonian
et al. [Chem. Mater. (1993), 5, 1690±1691]. We present
here a redetermination of greatly improved precision and at a
low temperature of 180 (2) K. The H atoms connected to
oxygen have been successfully located and the coordination
environments of the two crystallographically independent
vanadium centres have been properly elucidated. Large
channels, running along the a direction, contain water
molecules and 1,3-diammoniopropane cations that are
strongly hydrogen bonded to the anionic framework through
N+ÐH O and OÐH O interactions. One vanadyl (V O)
bond and the central ±CH2± group of 1,3-diammoniopropane
are located on a mirror plane
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