ABSTRACT
Employing in situ N-alkylation of the conjugated compound 9,10-bis(4-pyridyl)anthracene (bpanth) as structure-directing agent, a 3D inorganic-organic hybrid iodoplumbate, [Me2 (bpanth)][Pb4 I10 ] (1), was solvothermally prepared. The in situ N-alkylation of bpanth with alcohols was investigated. 1 features a novel 3D open framework based on an interesting Pb6 I24 cluster. UV/Vis spectroscopy analyses indicate that 1 is a potential semiconductor material with a narrow energy gap of 2.06â eV. It exhibits good catalytic activity in the visible-light-drived degradation of an organic dye. This work further illustrates that introducing conjugated organic molecules as templates is conducive to achieving semiconducting hybrid halometallates with narrow band gaps.
ABSTRACT
Three zeolitic pentaborates (H2en)[B5O8(OH)] (1, en = ethylenediamine), (Hen)2[Al(B5O10)] (2), (H2en)[NH(CH3)2][Al(B5O10)] (3) were solvothermally obtained by employing ethanediamine molecules as structure-directing agents (SDAs). The nonmetal borate of 1 features a noncentrosymmetric two-dimensional layered structure. Through introducing Al atoms as the linkers and regulating the reaction conditions of 1, two three-dimensional zeolitic open-framework aluminoborates, noncentrosymmetric (NCS) of 2 and centrosymmetric (CS) of 3, were achieved. Both 2 and 3 exhibit [Al(B5O10)] n2 n- zeolitic frameworks based on the same fundamental building blocks (FBBs). However, the different arrangements between two FBBs result in 2 showing a NCS framework with dia topology, while 3 presents CS framework with cag topology. The flexibility of linkages modes of the FBBs as well as the unique structure-directing functions play crucial roles in the different formations. Powder second-harmonic generation (SHG) measurements revealed that acentric 1 and 2 possess nonlinear optical activity and 2 is type I phase-matchable with SHG responses of â¼1.0 time for KDP (KH2PO4). Infrared and UV-vis diffuse reflectance spectroscopy, along with electronic structure calculations, were also performed for the materials.
ABSTRACT
Through regulating the pH values, a series of iodo-argentate/cuprate hybrids, [Me3 (4-TPT)]4 [Ag6 I18 ] (1, Me3 (4-TPT)=N,N',N''-trimethyl-2,4,6-tris(4-pyridyl)-1,3,5-triazine), [Me3 (4-TPT)][M5 I8 ] (M=Ag/2, Cu/2 a), [Me3 (3-TPT)][M5 I8 ] (Me3 (3-TPT)=N,N',N''-trimethyl-2,4,6-tris(3-pyridyl)-1,3,5-triazine, M=Ag/3, Cu/4), which exhibit adjustable structural variations with different dimensional structures, have been obtained under solvothermal conditions. They are directed by two types of in situ N-alkylation TPT-derivatives (Me3 (4-TPT) for 1/2/2 a and Me3 (3-TPT) for 3/4) and represent the isolated units (1), 1D polymeric chain (4), 2D layered structures (2/2 a, 3) based on diverse metal iodide clusters. These compounds possess reducing band gaps as compared with the bulk ß-AgI and CuI and belong to potential semiconductor materials. Iodocuprates feature highly efficient photocatalytic activity in the sunlight-induced degradation of organic dyes. The detailed study on the possible photocatalytic mechanism, including radical trapping tests and theoretical calculations, reveals that the N-alkylation TPT moieties contribute to the narrow semiconducting behavior and effectively inhibit the recombination of photogenerated electron-hole pairs, which result in an excellent visible-light-induced photocatalytic performance.
ABSTRACT
Transition-metal catalysts, particularly featuring a triple-layered core-shell structure, are very promising for practical application; however, reports on their synthesis and catalytic application for a cascade reaction were very rare. In this work, tiny Cu@Co@Ni core-shell nanoparticles (â¼3.3 nm) containing Cu core, Co middle shell, and Ni outer shell stabilized by metal-organic framework (MOF) were successfully synthesized to give a quadruple-layered Cu@Co@Ni/MOF at moderate conditions. The catalyst exhibited superior catalytic performance toward the in situ hydrogenation of nitroarenes using the H2 generated from the hydrolysis of ammonia borane (NH3BH3) under mild conditions. Interestingly, the Cu@Co@Ni/MOF also showed excellent catalytic activity toward CO oxidation reaction, which outperforms those of noble-metal catalysts. To our knowledge, this is the first report on transition-metal nanoparticles with a three-layered core-shell structure stabilized by MOF as a cooperative catalyst for cascade reaction and CO oxidation.
