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1.
Angew Chem Int Ed Engl ; 58(29): 9807-9810, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31050103

RESUMO

A new chloronium-containing salt, [Me2 Cl][Al(OTeF5 )4 ], was synthesized on multigram scale by means of a simple one-pot procedure. The isolated product can be handled at room temperature and used as a strong electrophilic methylation agent. This is demonstrated by the methylation of the very weak bases P(CF3 )3 , PF3 , MeI, and MeBr.

2.
Inorg Chem ; 58(7): 4052-4054, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30251538

RESUMO

K2Hg2Te3 was synthesized via a mercury-flux synthesis pathway. Single-crystal and powder X-ray diffraction reveal the compound to be isostructural to its lighter congener K2Hg2Se3, yet exhibiting enhanced photoconductivity and electrical conductivity of (several) orders of magnitude and a decreased thermal conductivity and band gap. In this report, we elaborate on the synthesis and properties of the novel ternary compound.

3.
Nat Commun ; 8(1): 1539, 2017 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-29146929

RESUMO

Metal-organic frameworks are known to contain defects within their crystalline structures. Successful engineering of these defects can lead to modifications in material properties that can potentially improve the performance of many existing frameworks. Herein, we report the high-throughput computational screening of a large experimental metal-organic framework database to identify 13 frameworks that show significantly improved methane storage capacities with linker vacancy defects. The candidates are first identified by focusing on structures with methane-inaccessible pores blocked away from the main adsorption channels. Then, organic linkers of the candidate structures are judiciously replaced with appropriate modulators to emulate the presence of linker vacancies, resulting in the integration and utilization of the previously inaccessible pores. Grand canonical Monte Carlo simulations of defective candidate frameworks show significant enhancements in methane storage capacities, highlighting that rational defect engineering can be an effective method to significantly improve the performance of the existing metal-organic frameworks.

4.
Chem Commun (Camb) ; 52(90): 13265-13268, 2016 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-27775108

RESUMO

The first hybrid crown ether with two adjacent disilane fragments was synthesized through reaction of O(Si2Me4Cl)2 (3) with O(C2H4OH)2. By means of DFT calculations, the complexation ability of 1,2,4,5-tetrasila[12]crown-4 (7) towards Li+ was determined to be considerably higher compared to [12]crown-4.

5.
Inorg Chem ; 55(13): 6725-30, 2016 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-27299466

RESUMO

K2Hg6Se7, Na2Hg3S2.51Se1.49, K2Hg3S1.03Se2.97, and K2Hg3S2.69Se1.31 were prepared by ionothermal treatment of K2Hg2Se3, Na2HgSe2, and K2Hg3Se4, respectively, in a nonclassical hydrosulfide ionic liquid (EMIm)(SH). In contrast to their lighter congeners, the title compounds could so far not be synthesized by inorganic polychalcogenide salt flux techniques. The applied method hence mimics polychalcogenide flux conditions, while operating at much lower temperatures below the decomposition temperature of the ionic liquid. It might thus be viewed as a pseudo-flux approach.

6.
Inorg Chem ; 55(9): 4441-7, 2016 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-27082743

RESUMO

The complexation ability of hybrid disilane and ethylene containing crown ether ring systems was analyzed using 1,2-disila[12]crown-4 (1), 1,2-disila[15]crown-5 (2), 1,2-disila[18]crown-6 (3), and 1,2,7,8-tetrasila[12]crown-4 (7). Alkali-metal complexes (Li(+), Na(+), K(+)) were obtained and analyzed via X-ray diffraction. The complex stability of [Li(1,2-disila[12]crown-4)](+) and [Li(1,2,7,8-tetrasila[12]crown-4)](+) was determined, in relation to the lithium complex of [12]crown-4, by density functional theory (DFT) calculations employing the BP86/def2-TZVP level of theory. In solution, the exchange of lithium cations between pure [12]crown-4 and hybrid [12]crown-4 is on even terms, as has been shown from the relative binding affinity of compounds 1 and 7 by means of dynamic proton nuclear magnetic resonance (NMR) spectroscopy.


Assuntos
Complexos de Coordenação/química , Éteres de Coroa/química , Metais Alcalinos/química , Compostos de Organossilício/química , Complexos de Coordenação/síntese química , Éteres de Coroa/síntese química , Isótopos , Lítio/química , Estrutura Molecular , Compostos de Organossilício/síntese química , Potássio/química , Espectroscopia de Prótons por Ressonância Magnética , Teoria Quântica , Sódio/química
7.
J Vis Exp ; (118)2016 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-28060345

RESUMO

The phases of "PbCh2" (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica glass ampules). Reduction of such phases by elemental alkaline metals in amines affords crystalline chalcogenidoplumbate(II) salts comprised of [PbTe3]2- or [Pb2Ch3]2- anions, depending upon which sequestering agent for the cations is present: crown ethers, like 18-crown-6, or cryptands, like [2.2.2]crypt. Reactions of solutions of such anions with transition-metal compounds yield (poly-)chalcogenide anions or transition-metal chalcogenide clusters, including one with a µ-PbSe ligand (i.e., the heaviest-known CO homolog). In contrast, the solid-state synthesis of a phase of the nominal composition "K2PbSe2" by successive reactions of the elements and by the subsequent solvothermal treatment in amines yields the first non-oxide/halide inorganic lead(IV) compound: a salt of the ortho-selenidoplumbate(IV) anion [PbSe4]4-. This was unexpected due to the redox potentials of Pb(IV) and Se(-II). Such methods can further be applied to other elemental combinations, leading to the formation of solutions with binary [HgTe2]2- or [BiSe3]3- anions, or to large-scale syntheses of K2Hg2Se3 or K3BiSe3 via the solid-state route. All compounds are characterized by single-crystal X-ray diffraction and elemental analysis; solutions of plumbate salts can be investigated by 205Pb and 77Se or 127Te NMR techniques. Quantum chemical calculations using density functional theory methods enable energy comparisons. They further allow for insights into the electronic configuration and thus, the bonding situation. Molecular Rh-containing Chevrel-type compounds were found to exhibit delocalized mixed valence, whereas similar telluridopalladate anions are electron-precise; the cluster with the µ-PbSe ligand is energetically favored over a hypothetical CO analog, in line with the unsuccessful attempt at its synthesis. The stability of formal Pb(IV) within the [PbSe4]4- anion is mainly due to a suitable stabilization within the crystal lattice.


Assuntos
Técnicas de Síntese em Fase Sólida , Cristalografia por Raios X , Elétrons , Ligantes , Espectroscopia de Ressonância Magnética , Difração de Raios X
8.
Angew Chem Int Ed Engl ; 54(38): 11283-8, 2015 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-26230752

RESUMO

Reactions of [K(18-crown-6)]2 [Pb2 Se3 ] and [K([2.2.2]crypt)]2 [Pb2 Se3 ] with [Rh(PPh3 )3 Cl] in en (ethane-1,2-diamine) afforded ionic compounds with [Rh3 (PPh3 )6 (µ3 -Se)2 ](-) and [Rh3 (CN)2 (PPh3 )4 (µ3 -Se)2 (µ-PbSe)](3-) anions, respectively. The latter contains a PbSe ligand, a rather uncommon homologue of CO that acts as a µ-bridge between two Rh atoms. Quantum chemical calculations yield a significantly higher bond energy for PbSe than for CO, since the size of the ligand orbitals better matches the comparably rigid Rh-Se-Rh angles and the resulting Rh⋅⋅⋅Rh distance. To rationalize the bent coordination of the ligand, orbitals with significant ligand contributions and their dependence on the bonding angle were investigated in detail.

9.
Inorg Chem ; 54(6): 2491-3, 2015 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-25719437

RESUMO

[(RhPPh3)6(µ3-Se)8]·0.5en (1; en = ethane-1,2-diamine), obtained by the reaction of [Pb2Se3](2-) anions with [Rh(PPh3)3Cl] in en, represents the first compound comprising a molecular [Rh6] octahedron with all faces capped by Se atoms. Analogous treatment of [Pb2Te3](2-) with [Pd(PPh3)2Cl2] yielded [Li4(en)10][Pd6(µ3-Te)8] (2), the first compound exhibiting a molecular, chalcogen-capped [Pd6] aggregate. Besides syntheses and structures of the title compounds, we report quantum-chemical calculations to understand the electronic properties of these molecular CHEVREL-like complexes.

10.
Angew Chem Int Ed Engl ; 53(18): 4699-703, 2014 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-24652783

RESUMO

The first inorganic lead(IV) compound without oxygen, nitrogen or halogen ligands attached to the lead atom was obtained as the potassium salt of the tetraselenidoplumbate(IV) anion [Pb(IV) Se4 ](4-) . It is stable under inert conditions which may enable the transfer of the chemistry of chalcogenidogermanate(IV) or chalcogenidostannate(IV) materials, to the lead homologues.

11.
Chem Commun (Camb) ; 48(92): 11295-7, 2012 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-22962663

RESUMO

Syntheses of [K([2.2.2]crypt)](+) salts of binary Pb-Bi Zintl anions and their reaction with ZnPh(2) or Ni(cod)(2), yielding ternary intermetalloid Ni-Pb-Bi or Zn-Pb-Bi clusters, proved the use of binary precursors with fully isoelectronic atoms as an efficient and thus valuable synthetic approach to this class of clusters. (207)Pb NMR and ESI mass spectra provided insight into the solution behavior of the binary or ternary cages.

12.
Inorg Chem ; 51(6): 3349-51, 2012 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-22384785

RESUMO

Two salts with one-dimensional, SiS(2)-type telluridostannate chain anions {[MSnTe(4)](2-)}(n), Rb(2)[HgSnTe(4)] (2) and (NMe(4))(2)[MnSnTe(4)] (3), were prepared by the reactions of [SnTe](4-) anions with Hg(2+) or Mn(2+) ions in solution. We present the crystal structures of 2 and 3, as well as the magnetic properties of the previously reported Cs(+) analogue Cs(2)[MnSnTe(4)] (1).

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