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1.
Chem Commun (Camb) ; 56(84): 12849-12852, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-32969428

RESUMO

We present a single molecular polyoxometalate cluster (K41[(P2W12Nb6O62)6{Mn3(OH)3(H2O)6}4{Mn3Na(H2O)16}]·26H2O) with controllable release of a large number of protons (∼40 per molecule) in its aqueous solution upon addition of a base. The deprotonation/protonation process is reversible with the clusters remaining intact. This molecule can also absorb up to 11 protons per cluster when an acid, HCl, was added to its original aqueous solution. To the best of our knowledge, such large proton absorption/release capacity along with excellent stability is unprecedented.

2.
Inorg Chem ; 59(10): 6747-6754, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32250607

RESUMO

We report the synthesis, characterization, and solution self-assembly of plenary Nb6P2W12-based transition-metal substituted polyoxometalate, which is obtained by simply adding transition metals (Co2+) into aqueous solution containing cluster [(NbO2)6P2W12O56]12-, which is obtained by an in situ synthetic method. The incorporation of Co2+ ions significantly affects the crystal structure, resulting in the formation of a 1D chain-like crystal and the first example of a niobotungstate-based cobalt derivative cluster. The behavior and stability of this cluster in solution are confirmed by time-resolved static light scattering, dynamic light scattering, small-angle X-ray scattering, and electrospray mass spectrometry studies.

3.
Dalton Trans ; 49(13): 4078-4083, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32134066

RESUMO

Recently, we demonstrated that the in situ formation of a building block is an attractive synthesis strategy for creating novel clusters with controllable structures. Herein, we present the design and synthesis of the first tantaloselenite polyoxoanion [Se4(TaO2)6(OH)4O17]4- (1) and a series of lanthanide derivatives (RE3+ = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+). In total, we report seven clusters that vary in both composition and structure but which share the same {Se4(TaO2)6} building block. The compounds are fully characterized by single-crystal X-ray diffraction, IR spectra, TG, and PXRD and their decolorization properties for RhB have also been investigated. Compound 1 exhibits good photocatalytic activity for the decolorization of RhB while the introduction of lanthanide into the framework can also maintain this activity.

4.
Chem Commun (Camb) ; 55(11): 1619-1622, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30657142

RESUMO

A series of CeF3 nanocrystals with uniform morphologies have been synthesized by introducing various polyoxometalates as dopants and shape modifiers. The results indicate that the shape and photoluminescence of the CeF3 nanocrystals could be finely tuned by changing the component and amount of the polyoxometalates.

5.
Dalton Trans ; 47(28): 9317-9323, 2018 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-29927451

RESUMO

Two monomeric non-classical tellurium-containing heteropolymolybdate-supported metal carbonyl derivatives (NH4)5H3{[Te2Mo12(OH)O44][Mn(CO)3]}·18H2O (1) and (NH4)8{[Te2Mo12(OH)O44][Re(CO)3]}·13H2O (2) have been successfully isolated in good yields. Compounds 1 and 2 are the first two examples of metal carbonyl derivatives of heteromolybdate with tellurium as the central atom. These two compounds have been thoroughly characterized by single-crystal X-ray diffraction, elemental analyses, X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and UV-Vis spectroscopy. The electrochemical catalytic activities of 1 and 2 including cyclic voltammetry and catalytic oxidation of nitrite have also been investigated.

6.
Chem Commun (Camb) ; 54(43): 5458-5461, 2018 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-29750224

RESUMO

A manganese(iii,iv)-tungsten(vi) supercluster based on 72 manganese ions (48 MnIV and 24 MnIII) and 48 tungsten(vi) centers [{MnIV24MnIII12O28(H2O)23}2(W24O120)2]40- has been prepared from the carboxylic Mn12 cluster. Its structure comprises two unprecedented cage-like Mn36W24 cores linked via two Mn-O-W bonds, leading to a Mn72W48 assembly. The inorganic synthetic mechanism was investigated through different synthesis methods and comprehensive ESI-MS tests.

7.
Dalton Trans ; 47(18): 6288-6292, 2018 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-29667674

RESUMO

A monomeric trinickel(ii)-substituted phosphotungstate [H9P2W15O62Ni3]9- ion is stabilized by grafting three {Re(CO)3} organometallic groups on the surface for the first time. Magnetic measurements manifest that the resulting complex, Na(NH4)5[P2W15O56Ni3(H2O)3(µ3-OH)3(Re(CO)3)3]·18H2O (1), displays overall ferromagnetic interactions with the presence of ZFS for Ni2+ at low temperature.

8.
Inorg Chem ; 56(22): 14053-14059, 2017 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-29095603

RESUMO

The high-nuclearity polyoxovanadate-based carboxylate derivative K6H[VV17VIV12(OH)4O60(OOC(CH2)4COO)8]·nH2O (1) has been successfully synthesized by conventional aqueous methods and structurally characterized. The [VV17VIV12(OH)4O60(OOC(CH2)4COO)8]7- polyanion is built up from three cages: one {VV17(OH)4O44} cage and two identical [(VIV3O6)2(OOC(CH2)4COO)4]8- cages. Of the three cages, the {VV17(OH)4O44} is a purely inorganic polyoxovanadate cluster, whereas each of the [(VIV3O6)2(OOC(CH2)4COO)4]8- cages is a vanadium-based organic-inorganic hybrid cluster framed via four adipate ligands linking simultaneously to two triangular {V3} units. The two [(VIV3O6)2(OOC(CH2)4COO)4]8- cages are covalently attached to the central {VV17(OH)4O44} cage via V-O-V bonds in a linear arrangement, resulting in a {V29}-based hybrid cluster skeleton. The catalytic properties of compound 1 for the oxidation of sulfides by tert-butyl hydroperoxide were investigated, and the result indicates that 1 exhibits excellent catalytic activity for the oxidation of sulfides under mild conditions.

9.
Sci Rep ; 7(1): 10653, 2017 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-28878281

RESUMO

Eight new lanthanide derivatives containing 6-peroxoniobio-4-phosphate building block, [LnIII(H2O)6]2[H4(NbO2)6P4O24]·nH2O [Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), Yb (8), 1-5, 7, 8 n = 12; 6 n = 9], have been successfully obtained using an in-situ strategy and fully characterized in the solid state by single-crystal X-ray diffraction, IR spectra, TG-MS, PXRD. Structural analyses indicate that these isostructural polyanions 1-8 consist of one [P4(NbO2)6O24]10- (P 4 (NbO 2 ) 6 ) clusters and two pendant Ln3+ cations. In these compounds, P 4 (NbO 2 ) 6 clusters are connected by lanthanide cations to form extended two-dimensional architectures. The approach takes advantage of the ability of in-situ formed P 4 (NbO 2 ) 6 cluster to build frameworks by using it as ligands to lanthanide ions. The photoluminescence (PL) and lifetime decay behaviors of 1, 3 and 4 in solid state have been performed at room temperature. The PL emission of 1, 3 and 4 is mainly derived from the characteristic 5D0→7FJ (J = 1, 2, 3, 4), 5D4→7FJ (J = 6, 5, 4, 3) and 4F9/2→6H J (J = 15/2, 13/2, 11/2) transitions of the EuIII, TbIII and DyIII cations, respectively.

10.
Dalton Trans ; 46(38): 12981-12987, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28933485

RESUMO

A series of new lanthanide-containing peroxoisopolyoxotungstates, K6Na4[H32{Ln4(WO4)(H2O)16[W7O22(O2)2]4}3]·105H2O [Ln = CeIII (1), NdIII (2), SmIII (3), TbIII (4), ErIII (5)], have been successfully synthesized and structurally characterized. All polyanions [Ln(WO4)(H2O)16{W7O22(O2)2}4]14- are isostructural and consist of a central [Ln(WO4)(H2O)16]10+ cluster surrounded by four peripheral [W7O22(O2)2]6- units. They could act as efficient recyclable catalysts for the epoxidation of various alkenes including different cycloalkenes, styrene derivatives, internal and long-chain alkenes. Under optimal conditions, catalyst 2 displays the best catalytic activity for the oxidation of cyclooctene with high cyclooctene conversion (98.3%) and excellent selectivity (up to 99%) and could be reused for three cycles with a negligible decrease in reactivity.

11.
Inorg Chem ; 56(17): 10131-10134, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28813146

RESUMO

A monomeric tricobalt(II)-substituted phosphotungstate polyanion, [H9P2W15O62Co3]9-, is stabilized by the attachement of an organometallic group, {Mn(CO)3}, for the first time. The resulting polyoxometalate-supported [Mn(CO)3]+ complex (1) can be used as an efficient catalyst in the cycloaddition of CO2 with epoxides under mild reaction conditions with pyrrolidinium bromide as a cocatalyst. Besides, magnetic measurements show that the compound exhibits weaker ferromagnetic interactions at low temperature.

12.
Molecules ; 22(8)2017 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-28805742

RESUMO

Two novel heteropolyoxomolybdate [XMo8O31]n- (X = Ge(1) or P(2)) manganese carbonyl derivatives [(CH3)4N]6H6{MnII(GeMo8O31)[MnI(CO)3]2}2·12H2O (1) and [(CH3)4N]4H6{MnII(PMo8O31)[MnI(CO)3]2}2·14H2O (2), have been successfully synthesized and characterized in the solid state by single crystal X-ray diffraction, IR and thermogravimetric analysis, and in solution by UV-Vis spectroscopy and electrochemistry. The two polyoxomolybdate-based organometallic compounds 1 and 2 represent rare examples of transition metal sandwich-based polyoxometalate metal carbonyl derivatives (PMCDs), in which the organic-inorganic hybrids are composed of four Mn(CO)3⁺ groups symmetrically occupied the tetravacant sites of dimeric heteropolyoxomolybdate {Mn2(XMo8O31)2}n- through MnI-O-Mo bonds. The carbonyl functionalized Mn atoms are octahedrally coordinated via three µ2-oxygens of the [XMo8O31]n- unit and three carbonyl carbon atoms. Interestingly, 1 and 2 form a psedocuboidal ring Mn(CO)3Mo3O12 with {Mn(CO)3}⁺ occupying the three fold axis of the Mo3O12 octahedral triad. Beside this, the two centrally placed adjacent MnII atoms show intramolecular Mn∙∙∙Mn interactions of 3.11 and 3.16 Å in 1 and 2, respectively. Significant n→π* and O···O intermolecular interactions between the orthogonally aligned adjacent carbonyl groups through the overlap of lone-pair electrons on oxygen atoms with the antibonding orbital (π*) of the adjacent carbony carbon atom of the subsequent units in 1 and 2 were observed. The electrochemical properties of the two compounds were also been investigated.


Assuntos
Manganês/química , Molibdênio/química , Compostos Organometálicos/química , Cristalografia por Raios X/métodos , Eletroquímica/métodos , Elétrons , Modelos Moleculares , Estrutura Molecular , Oxigênio/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Termogravimetria/métodos , Difração de Raios X/métodos
13.
Inorg Chem ; 56(17): 10119-10122, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28809099

RESUMO

A novel 24-niobic-2-tellurite, [H2Te2Nb24O72]14-, was isolated by incorporating tellurite anions into a polyoxoniobate cage. The synthesized cluster represents the first example of a sandwich-type polyoxoniobate with the largest telluroniobate aggregate. Furthermore, the hybrid material acts as an efficient catalyst for the decolorization of basic fuchsin.

14.
Inorg Chem ; 56(10): 5537-5543, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28467059

RESUMO

Polyoxometalates (POMs) of Nb and Ta are greatly different from those of Mo, W, and V that have been studied extensively and developed well. The latter can be formed simply by acidification of their aqueous monomeric oxoanions and has found application areas from catalysis to magnetism, materials science, medicine, and nanotechnology. Even now the polyoxoniobate (PONb) chemistry has accelerated dramatically over the last 15 years, and a vast expansion of available PONbs has been reported. However, after nearly 200 years of POM research, Ta-based POM chemistry is still at its infant stage and only dominated by the isopolyoxotantalate ions (Ta6 and Ta10) and transition-metal-capped Ta6 species, along with two Ti-substituted polyoxotantalates [Ti2Ta8O28]8- and [Ti12Ta6O44]10- reported very recently. In this study, we discover two novel peroxotantalophosphate clusters [P4(TaO2)6O25]12- (1) and [P4(TaO2)6O24]10- (2) by incorporating phosphorus heteroatom into Ta-oxo framework, which represent the first two examples of heteropolytantalate. Interestingly, two P2Ta3 half-units are cis- and trans-condensed in 1 and 2, leading to "open" and "closed" configurations, respectively. These two chemically and structurally related clusters can be isolated in a controlled manner, and the yields are relatively high. Both compounds were characterized in the solid state by single-crystal X-ray diffraction, 31P MAS NMR, FT-IR, TGA, and elemental analysis as well as by 31P NMR in solution. The results presented here provide a strategy to be applicable to other heteroatom-incorporated polyoxotantalates and further expand the phase space for polyoxotantalate chemistry.

15.
Dalton Trans ; 46(16): 5398-5405, 2017 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-28386614

RESUMO

Two novel trans-isomers of 1 : 2-type lanthanide-containing monolacunary Dawson-type tungstophosphates [Ln(α2-P2W17O61)2]17- (Ln = LaIII (1), CeIII (2)) were successfully isolated and characterized by elemental analysis, IR, TG, and 31P NMR studies. Both polyanions 1 and 2 consist of one Ln3+ ion sanwiched between two monolacunary Dawson-type tungstophosphates fragments [α2-P2W17O61]10- oriented at 180° with respect to each other. The solid-state and solution 31P NMR spectroscopy revealed that the trans-[Ce(α2-P2W17O61)2]17- species probably quickly isomerizes to the cis-isomer species in solution.

16.
Dalton Trans ; 46(5): 1368-1371, 2017 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-28067387

RESUMO

A new heteropolyniobate, [Fe3Nb25O76]18-, persists in aqueous solution by means of electrospray ionization mass spectrometry. It has been synthesized and characterized by IR, TGA, EDX-SEM, magnetic and single-crystal X-ray diffraction, and it features an Fe-centred Nb-Keggin unit {Fe3Nb10}.

17.
Dalton Trans ; 45(38): 15236-15241, 2016 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-27711713

RESUMO

A new trimeric cluster [(SiW9Nb3O38)3MnO3(H2O)3]13- (1) with three Keggin-type trilacunary SiW9 units connected by a {MnNb9} core were structurally characterized. The polyanion 1 features three corner-shared {Nb3O3} fragments that are linked to each other on two sides via three Nb-O-Nb bridges and by a {MnII} linker. To the best of our knowledge, polyanion 1 represents the first example of a trimeric niobotungstate cluster reported to date, and is revealed for the first time uniting a family of polytungstosilicate clusters. The formation of polyanion 1 exemplifies the reactivity of {(NbO2)3SiW9} with a manganese metal ion, defining a new in situ synthetic strategy for {(NbO2)3SiW9}-based derivatives, featuring POM chemistry between Nb/W mixed-addendum POMs and various transition-metal or lanthanide species.

18.
Dalton Trans ; 45(41): 16173-16176, 2016 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-27711767

RESUMO

[H4Ni10(H2O)8Nb32O102]20-, representing the first high-nuclear nickel-cation-bridged polyoxoniobate, has been synthesized. It incorporates two [{Ni2O4}(H2O)2(Nb6O19)]12- and two [Ni3(H2O)2Nb10O34]12- subunits exhibiting a rhombus-like architecture. Furthermore, the solution behaviour was examined by electrospray ionization mass spectrometry and the magnetic properties in the low temperature range indicate the presence of ferromagnetic interactions.

19.
Chemistry ; 22(31): 10983-9, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27345965

RESUMO

Novel Fe10 and Fe14 clusters [Rb9 Cs4 H37 Fe10 O34 (A-α-PW9 O31 )3 (OH)3 ]⋅36 H2 O (1) and [H3 Rb3 Fe14 (OH)12 (PO4 )6 (B-α-PW9 O34 )2 ]⋅21 H2 O (2) were synthesized and characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and magnetic studies, and in solution by electrochemistry. Cluster 1 is a decameric Fe(III) polyanionic cluster encapsulating a cesium atom in the center. Cluster 2 is a unique tetradecanuclear Fe(III) sandwich structure with phosphate-linked units featuring two quasicubic Fe4 O4 moieties. Apparently, 2 has the highest nuclearity of all known Fe(III) sandwich-type polyoxometalate clusters. Clusters 1 and 2 also act as photocatalysts with platinum as cocatalyst for H2 evolution from light-driven water splitting. Changes in the cyclovoltammetric patterns with variations in pH were observed for 1 and 2, most likely due to intermolecular interactions among the high-nuclearity Fe(III) cluster cores and subsequent changes in the acid-base properties of the two reduced POMs. Magnetic studies provide evidence of antiferromagnetic interactions in 1 and 2. TGA showed that complexes 1 and 2 decompose between 580 and 590 °C.

20.
Dalton Trans ; 45(15): 6726-31, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-26974953

RESUMO

A novel isopentatungstate-supported metal carbonyl derivative KH[(CH3)4N]3{[Re(CO)3]4[(µ2-OH)(µ3-O)(W5O18)]}·6H2O () has been synthesized and characterized. Compound represents the second example of isopolyoxotungstate-supported metal carbonyl derivative. The catalysis of for alkene epoxidation with H2O2 was investigated, and was found to efficiently catalyze the epoxidation of cyclooctene with high conversion (98.9%) and excellent selectivity (99%). Furthermore, the solution behavior of the polyanion was also explored using electrospray ionization mass spectrometry.

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