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1.
Artigo em Inglês | MEDLINE | ID: mdl-32608037

RESUMO

In this work, the largest heterometallic supertetrahedral clusters, [Zn6Ge16]4- and [Cd6Ge16]4-, were directly self-assembled through highly-charged [Ge4]4- units and transition metal cations, in which 3-center-2-electron σ bonding in Ge2Zn or Ge2Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time-dependent HRESI-MS spectra show that the larger clusters grow from smaller components with a single [Ge4]4- and ZnMes2 units. Calculations performed at the DFT level indicate a very large HOMO-LUMO energy gap in [M6Ge16]4- (2.22 eV), suggesting high kinetic stability that may offer opportunities in materials science. These observations offer a new strategy for the assembly of heterometallic clusters with high symmetry.

2.
J Am Chem Soc ; 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32689789

RESUMO

We report the synthesis of two new cluster anions [Cu4@E18]4- (E = Sn, Pb), in which a Cu4 subunit is incorporated into a continuous E18 tetrel cage. Both anions are characterized by X-ray crystallography and mass spectrometry, complemented by quantum chemical calculations which highlight the relationships to known Zintl clusters including the stannaspherenes and plumbaspherenes, [M@Sn12]q- and [M@Pb12]q-, the Matryoshka bronze [Sn@Cu12@Sn20]12- and also [Pd2@E'18]4- (E' = Ge, Sn).

3.
Nat Commun ; 11(1): 3477, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651376

RESUMO

Gold nanoparticles have been used for centuries, both for decoration and in medical applications. More recently, many of the major advances in cluster chemistry have involved well-defined clusters containing tens or hundreds of atoms, either with or without a ligand shell. In this paper we report the synthesis of two gold/lead clusters, [Au8Pb33]6- and [Au12Pb44]8-, both of which contain nido [Au@Pb11]3- icosahedra surrounding a core of Au atoms. Analogues of these large clusters are not found in the corresponding Ag chemistry: instead, the Ag-centered nido icosahedron, [Ag@Pb11]3-, is the only isolated product. The structural chemistry, along with the mass spectrometry which shows the existence of [Au2Pb11]2- but not [Ag2Pb11]2-, leads us to propose that the former species is the key intermediate in the growth of the larger clusters. Density functional theory indicates that secondary π-type interactions between the [Au@Pb11]3- ligands and the gold core play a significant part in stabilizing the larger clusters.

4.
Chem Commun (Camb) ; 56(48): 6583-6586, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32400811

RESUMO

In this work, we report a dimeric cluster anion, {[CuGe9Mes]2}4-, which was isolated as the [K(2,2,2-crypt)]+ salt and characterized by using single-crystal X-ray diffraction and ESI mass spectroscopy. The title cluster represents the first locally σ-antiaromatic compound in the solid state, as well as the first heteroatomic antiaromatic compound.

5.
Dalton Trans ; 49(12): 3700-3705, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-31215558

RESUMO

In this work, a cadmium-phosphonate network was prepared based on a tetrahedral shaped tetraphosphonic acid linker. The resulting three-dimensional compound Cd4(H4L)2(phen)2(H2O)4 (1) exhibited a rapid and efficient adsorption of Congo red (CR) dye, the adsorption capacity of which reached 684 mg g-1. Furthermore, this adsorbent showed excellent structural stability and adsorptive recyclability after three times of adsorption and desorption. The absorption kinetics fitted well with the pseudo-second-order kinetic model, revealing that the adsorption of the cadmium-phosphonate compound undergoes a chemical process, where hydrogen bonding between the amide groups (from CR) and the uncoordinated phosphonate oxygen atoms of the compound plays a pivotal role.

6.
Chemistry ; 26(9): 2073-2079, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31851761

RESUMO

The chemical bonding of Zintl clusters is still an evolving and hot topic in modern chemistry. In this paper we synthesized a novel [K([2.2.2]crypt)]4 [In8 Bi13 ] complex in a condensed phase. The quantum chemical calculations and X-ray data revealed that the compound consists of the 1:1 mixture of [Bi@In8 Bi12 ]3- and [Bi@In8 Bi12 ]5- clusters. To the date, those clusters are the largest binary clusters composed of In and Bi elements. Herein, we introduce a spherical aromatic description of chemical bonding for such clusters. We show through AdNDP, ELF, and induced magnetic field and quantitative NICS analyzes that both clusters are spherically aromatic which explains their high symmetry, stability, and peculiar magnetic properties. We believe that this work will help researchers in the further development and understanding of chemical bonding in Zintl clusters.

7.
Dalton Trans ; 48(42): 15888-15895, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31589230

RESUMO

A new Zintl cluster, [(Ni@Sn9)In(Ni@Sn9)]5-, has been isolated in two distinct isomeric forms, one where both Ni@Sn9 units are coordinated to the bridging In atom in an η3- mode, the other where one is η3- and the other η4-. Density functional theory indicates that the energetic separation between these two structures is minimal, suggesting that crystal packing plays a decisive role in the structural chemistry. A comparison of the electronic structure of [(Ni@Sn9)In(Ni@Sn9)]5- with [(Ni@Ge9)Ni(Ni@Ge9)]4-, which has four fewer valence electrons, sheds some light on possible mechanisms that lead to the fusion of cluster fragments.

8.
Chemphyschem ; 20(16): 2060-2062, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31184431

RESUMO

Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70-1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.

9.
Chem Sci ; 10(16): 4394-4401, 2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31057766

RESUMO

Through relatively subtle changes in reaction conditions, we have been able to isolate four distinct Rh/Sn cluster compounds, [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and [Rh3@Sn24]5-, from the reaction of K4Sn9 with [(COE)2Rh(µ-Cl)]2(COE = cyclooctene). The last of these has a hitherto unknown molecular topology, an edge-fused polyhedron containing three Rh@Sn10 subunits, and represents the largest endohedral Group 14 Zintl cluster yet to have been isolated from solution. DFT has been used to place these new species in the context of known cluster chemistry. ESI-MS experiments on the reaction mixtures reveal the ubiquitous presence of {RhSn8} fragments that may play a role in cluster growth.

10.
Angew Chem Int Ed Engl ; 58(25): 8367-8371, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31013397

RESUMO

We report the characterization of the compound [K([2.2.2]crypt)]4 [In8 Sb13 ], which proves to contain a 1:1 mixture of [Sb@In8 Sb12 ]3- and [Sb@In8 Sb12 ]5- . The tri-anion displays perfect Th symmetry, the first completely inorganic molecule to do so, and contains eight equivalent In3+ centers in a cube. The gas-phase potential energy surface of the penta-anion has eight equivalent minima where the extra pair of electrons is localized on one In+ center, and these minima are linked by low-lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron density is obtained from a model where the structure of the 5- cluster lies close to the gas-phase transition state.

11.
Inorg Chem ; 58(9): 6312-6319, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31017773

RESUMO

The incorporation of heterometallic atoms into the structure of titanium-oxygen nanomaterials is one of the known and effective strategies to develop new high-performance photovoltaic active materials. In this study, we have synthesized three benzoic acid-stabilized heterometallic titanium oxo clusters with the different transition metals Co, Cu, and Cd, formulated as [Ti4Co2(µ2-O)2(µ3-O)2(C6H5COO)12(CH3CN)2]·2CH3CN (1), [Ti5Cu4(µ3-O)6(C6H5COO)16] (2), and [Ti12Cd5(µ2-O)(µ3-O)15(µ4-O)2(C6H5COO)22(C6H5COOH)(CH3CN)]·CH3CN·C6H5COOH (3), and then we characterized their structures. UV-vis spectroscopy analysis revealed an enhanced UV-vis-light absorption of those heterometallic clusters. The density functional theory calculations indicated that charge transfer occurs from the p orbital of O atoms to the d orbital of Ti atoms in the TiO core (O → Ti) as well as from the metal to the core in 1 and 2. We also measured the photocurrent response and photocatalytic H2 evolution, which shows enhancement in the photocurrent intensity and good H2 evolution ability because of the cooperative effect of heterometal doping in titanium oxo clusters.

12.
Dalton Trans ; 48(4): 1246-1250, 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30542680

RESUMO

A novel 3D metal-organic framework based on Ni4 clusters as nodes has been synthesized using a tetrahedral linker of 5,5',5''-(methylsilanetriyl)triisophthalic acid (H6L). The compound possesses 1D channels with potential pore volumes that can accommodate guest molecules. Investigations on the coupling reaction of epoxides and CO2 indicate that the compound can be used as an efficient catalyst for CO2 chemical fixation, and its catalytic performance is greatly superior to most MOF-based catalysts. Additionally, compound 1 can be recycled at least five times without compromising its activity.

13.
Inorg Chem ; 57(24): 15370-15378, 2018 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-30481012

RESUMO

Six new 2-fold interpenetrated uranyl coordination polymers with two distinct types of (6,3)-net layers, (H3O)[(UO2)(L)]·H2O (1), (Hbipy)[(UO2)(L)]·H2O (2), (Hbib)[(UO2)(L)]·H2O (3), (H2dib)[(UO2)2(L)2]·H2O (4), [Zn(H2O)6][(UO2)2(L)2]·5H2O (5), and (NH4)[(UO2)(L)]·H2O (6), (bipy = 2,2'-bipyridine, bib = 4,4'-di(1 H-imidazol-1-yl)-1,1'-biphenyl, and dib = 1,4-di(1 H-imidazol-1-yl)benzene), were hydrothermally prepared from a tripodal polycarboxylate ligand, tri(4-carboxyphenyl)phenylsilane (H3L), with different N-bearing organic templates as the stacking templates and charge compensators. Structural analyses indicate that these compounds comprise two sets of conformational supramolecular isomers because of the same framework compositions but different conformations of the carboxylate ligands. The solid-state emission spectra of compounds 1-6 were recorded. Ion-exchange studies revealed that the ammonia hydrate in 6 can be selectively substituted by alkali metal cations with appropriate ionic radii, and that the resulting structures remain stable, as demonstrated by crystallographic characterization.

14.
Chem Commun (Camb) ; 54(51): 7093-7094, 2018 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-29881839

RESUMO

Correction for 'A microporous Cu-MOF with optimized open metal sites and pore spaces for high gas storage and active chemical fixation of CO2' by Chao-Ying Gao et al., Chem. Commun., 2016, 52, 11147-11150.

15.
Chemistry ; 24(55): 14583-14597, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29774973

RESUMO

Originally, the concepts of aromaticity and antiaromaticity were introduced to explain the stability and reactivity of unsaturated organic compounds. Since then, they have been extended to other species with delocalized electrons including various saturated systems, organometallic compounds, and even inorganic clusters and molecules. In this Minireview, we focus on the most recent progress of using these concepts to guide experimental synthesis and rationalize geometrical and electronic structures of a particular family of polyanions composed of Group 14 and 15 elements, namely Zintl clusters.

16.
Inorg Chem ; 57(8): 4419-4426, 2018 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-29570281

RESUMO

Exploitation of new materials for the removal of long-lived and highly radioactive actinides and their fission products produced in the nuclear fuel cycle is crucial for radionuclide management. Here, two rare porous anionic uranyl-organic frameworks (UOFs) have been successfully synthesized by a judicious combination of the tetratopic carboxylate ligand 1,3,6,8-tetrakis( p-benzoic acid)pyrene (H4TBAPy) and D3 h-symmetrical triangular [UO2(COO)3]-. The resulting two compounds exhibit different architectures, albeit with similar coordination modes. Of interest is that they have excellent adsorption performance on Cs+ from aqueous solution. The high removal efficency would make them promising in applications of radioactive waste management. Notably, the framework of compound 2, [(CH3)2NH2]4[(UO2)4(TBAPy)3]·22DMF·37H2O is sufficiently robust to allow the accessibility of intriguing single crystals of a Cs+-adsorbed derivative, which helps to elucidate the adsorption mechanism. The structural, bonding, and spectroscopic properties of the above compounds are examined using relativistic density functional theory (DFT). It is found that the adsorption toward cesium on UOFs is energetically favored, which features largely ionic bonds and is dominated by electrostatic attraction.

17.
Inorg Chem ; 57(6): 3025-3034, 2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29512998

RESUMO

The binary cluster [Co@Sn9]4- (1) was extracted directly from ethylenediamine (en) solutions of an intermetallic precursor with nominal composition "K5Co3Sn9", and its reactions with various organometallic reagents were explored. Reaction with Ni(PPh3)2(CO)2 gives [Co@Sn9Ni(CO)]3- (2), a Co-centered closo-Sn9Ni bicapped square antiprism. Analogous reactions with Ni(COD)2, Pt(PPh3)4, and Au(PPh3)Ph led to the isolation of [Co@Sn9Ni(C2H4)]3- (3), [Co@Sn9Pt(PPh3)]3- (4), and [Co@Sn9AuPh]3- (5), respectively. 3 is structurally similar to 2 but significantly distorted from a closo-cluster with one open square face. The coordination of [CoSn9]3- by PtPPh3 (4) or AuPh (5) induces a structural transformation in the CoSn9 core, from a monocapped square antiprism ( C4 v) to a tricapped trigonal prismatic structure ( pseudo- C3 v), with the transition metal fragment capping a triangular face. The four trimetallic anions presented here represent a new family of ternary functionalized Zintl clusters incorporating a d9 transition metal center. All clusters were characterized by single-crystal X-ray diffraction and electrospray ionization mass spectrometry (ESI-MS).

18.
Chem Commun (Camb) ; 54(14): 1758-1761, 2018 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-29380826

RESUMO

With coordinatively unsaturated metal centers decorating the channel walls, a MnII phosphonate exhibits highly efficient and substrate size-selective catalysis in the context of CO2 chemical conversion into cyclic carbonates under 1 atm pressure and at room temperature, proving to be a promising heterogeneous catalyst in an eco-friendly and energy efficient way.

19.
Chemistry ; 24(12): 2952-2961, 2018 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-29265501

RESUMO

The exploitation of new titanium-based coordination polymers (Ti CPs) with high crystallinity is difficult but highly desirable for their potential applications in photocatalysis. Herein, a cluster-cooperative assemble strategy is developed to synthesize Ti CPs. By utilizing various bifunctional ligands containing carboxylate acids and N-donor groups, we successfully assembled the zero-dimensional (0D) [(Ti3 O)(iPrO)8 ]2+ or [(Ti4 O2 )(iPrO)6 ]6+ clusters into one-dimensional (1D) tube-, ribbon-, or helical chain-shape architectures, two-dimensional (2D) layered structures, and a rare parallel 2D→three-dimensional (3D) polycatenation framework with various copper iodide dopants, including rhombus- or wing-shaped Cu2 I2 and tetrahedron- or ladder-shaped Cu4 I4 . The as-synthesized compounds display strong absorption in the visible region with narrow band gaps ranging from 1.70 to 2.72 eV and exhibit good photocatalytic activities in the degradation of organic pollutants.

20.
Chemistry ; 24(3): 699-705, 2018 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-29071743

RESUMO

We report the successful isolation and structural elucidation of two bimetallic doped [Co2 @Ge16 ]4- clusters (α and ß form), which were synthesized through the reaction of [{(ArN)2 CtBu}Co(η6 -toluene)] (Ar=2,6-diisopropylphenyl) and K4 Ge9 in ethylenediamine (en) solution and co-crystallized together in [K(2,2,2-crypt)]4 [Co2 @Ge16 ]⋅en. The α-[Co2 @Ge16 ]4- isomer prefers a distinct D2h 3-connected architecture, whereas the deltahedral isomeric ß-[Co2 @Ge16 ]4- isomer adopts a quasi-C2h geometry and can be seen as coupling of two distorted arachno-[Co@Ge10 ] units. Chemical bonding analyses indicate that the skeleton of the α isomer is mainly composed of localized bonds, whereas only multicenter bonding interactions govern the geometry of the ß isomer, which was further found to exhibit a fluxional behavior. The coexistence of both isomers within one unit cell links the 3-connected clusters with their deltahedral congeners, thus highlighting the structural and electronic flexibility of such discreet cluster systems.

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