The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Noritaka Mizuno - One of the best experts on this subject based on the ideXlab platform.
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layered assemblies of a dialuminum substituted silicotungstate trimer and the reversible interlayer cation exchange properties
Inorganic Chemistry, 2011Co-Authors: Yuji Kikukawa, Kazuya Yamaguchi, Mitsuhiro Hibino, Noritaka MizunoAbstract:Two polyoxometalate assemblies, TBA9[{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3] (1; TBA = tetra-n-butylammonium) and TBA6Li3[{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3]·18H2O (2), were synthesized by trimerization of a dialuminum-substituted silicotungstate monomer. Both 1 and 2 possessed a layered structure composed of a basal sheet unit [TBA3{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3]6– and interlayer cations. The interconversion between 1 and 2 reversibly took place through interlayer cation exchange.
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synthesis of a dialuminum substituted silicotungstate and the diastereoselective cyclization of citronellal derivatives
Journal of the American Chemical Society, 2008Co-Authors: Yuji Kikukawa, Syuhei Yamaguchi, Yoshinao Nakagawa, Kazuhiro Uehara, Sayaka Uchida, Kazuya Yamaguchi, Noritaka MizunoAbstract:A novel dialuminum-substituted silicotungstate TBA3H[γ-SiW10O36{Al(OH2)}2(μ-OH)2]·4H2O (1, TBA = tetra-n-butylammonium) was synthesized by the reaction of the potassium salt of [γ-SiW10O36]8− (SiW10) with 2 equiv of Al(NO3)3 in an acidic aqueous medium. It was confirmed by the X-ray crystallographic analysis that compound 1 was a monomer of the γ-Keggin dialuminum-substituted silicotungstate with the {Al2(μ-OH)2} diamond core. The cluster framework of 1 maintained the γ-Keggin structure in the solution states. The reaction of 1 with pyridine yielded TBA3[(C5H5N)H][γ-SiW10O36{Al(C5H5N)}2(μ-OH)2]·2H2O (2), and the molecular structure was successfully determined by the X-ray crystallographic analysis. In compound 2, two of three pyridine molecules coordinated to the axial positions of aluminum centers and one of them existed as a pyridinium cation, showing that compound 1 has two Lewis acid sites and one Bronsted acid site. Compound 1 showed high catalytic activity for the intramolecular cyclization of citro...
Zhitong Yao - One of the best experts on this subject based on the ideXlab platform.
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dilithium Dialuminium trisilicate crystalline phase prepared from coal fly ash
Journal of Materials Engineering and Performance, 2012Co-Authors: Zhitong Yao, Meisheng XiaAbstract:The dilithium Dialuminium trisilicate phase Li2Al2Si3O10 was prepared using coal fly ash and lithium hydroxide monohydrate LiOH·H2O as precursors. The influences of various preparation conditions on Li2Al2Si3O10 forming were investigated. The results showed that the optimum additive amount of LiOH·H2O was about 20%. The onset of calcining temperature and time was identified as 980 °C and 1 h, respectively. XRD analysis indicated that the content of Li2Al2Si3O10 phase increased at the expense of quartz and mullite, with calcining temperatures increasing and time extending. SEM observation revealed that the calcined samples were drastically interlocked together with the prolonging of time. The obtained Li2Al2Si3O10 phase was well crystallized and with small grain size.
Yuji Kikukawa - One of the best experts on this subject based on the ideXlab platform.
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layered assemblies of a dialuminum substituted silicotungstate trimer and the reversible interlayer cation exchange properties
Inorganic Chemistry, 2011Co-Authors: Yuji Kikukawa, Kazuya Yamaguchi, Mitsuhiro Hibino, Noritaka MizunoAbstract:Two polyoxometalate assemblies, TBA9[{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3] (1; TBA = tetra-n-butylammonium) and TBA6Li3[{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3]·18H2O (2), were synthesized by trimerization of a dialuminum-substituted silicotungstate monomer. Both 1 and 2 possessed a layered structure composed of a basal sheet unit [TBA3{γ-H2SiW10O36Al2(μ-OH)2(μ-OH)}3]6– and interlayer cations. The interconversion between 1 and 2 reversibly took place through interlayer cation exchange.
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synthesis of a dialuminum substituted silicotungstate and the diastereoselective cyclization of citronellal derivatives
Journal of the American Chemical Society, 2008Co-Authors: Yuji Kikukawa, Syuhei Yamaguchi, Yoshinao Nakagawa, Kazuhiro Uehara, Sayaka Uchida, Kazuya Yamaguchi, Noritaka MizunoAbstract:A novel dialuminum-substituted silicotungstate TBA3H[γ-SiW10O36{Al(OH2)}2(μ-OH)2]·4H2O (1, TBA = tetra-n-butylammonium) was synthesized by the reaction of the potassium salt of [γ-SiW10O36]8− (SiW10) with 2 equiv of Al(NO3)3 in an acidic aqueous medium. It was confirmed by the X-ray crystallographic analysis that compound 1 was a monomer of the γ-Keggin dialuminum-substituted silicotungstate with the {Al2(μ-OH)2} diamond core. The cluster framework of 1 maintained the γ-Keggin structure in the solution states. The reaction of 1 with pyridine yielded TBA3[(C5H5N)H][γ-SiW10O36{Al(C5H5N)}2(μ-OH)2]·2H2O (2), and the molecular structure was successfully determined by the X-ray crystallographic analysis. In compound 2, two of three pyridine molecules coordinated to the axial positions of aluminum centers and one of them existed as a pyridinium cation, showing that compound 1 has two Lewis acid sites and one Bronsted acid site. Compound 1 showed high catalytic activity for the intramolecular cyclization of citro...
Uwe Kolitsch - One of the best experts on this subject based on the ideXlab platform.
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m m3 2as haso4 6 m m3 tlga csga csal three new metal arsenates containing aso6 octa hedra
Acta Crystallographica Section E: Crystallographic Communications, 2018Co-Authors: Karolina Schwendtner, Uwe KolitschAbstract:The crystal structures of hydrothermally synthesized (T = 493 K, 7 d) thallium(I) digallium arsenic(V) hexakis[hydrogenarsenate(V)], TlGa2As(HAsO4)6, caesium digallium arsenic(V) hexakis[hydrogenarsenate(V)], CsGa2As(HAsO4)6, and caesium Dialuminium arsenic(V) hexakis[hydrogenarsenate(V)], CsAl2As(HAsO4)6, were solved by single-crystal X-ray diffraction. The three compounds are isotypic and adopt the structure type of RbAl2As(HAsO4)6 (R\overline{3}c), which itself represents a modification of the RbFe(HPO4)2 structure type and consists of a tetrahedral–octahedral framework in which the slightly disordered M+ cations are located in channels. The three new compounds contain AsO6 octahedra assuming the topological role of M3+O6 octahedra. The As—O bond lengths are among the shortest As—O bond lengths known so far in AsO6 octahedra.
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M+M3+2As(HAsO4)6 (M+M3+ = TlGa, CsGa, CsAl): three new metal arsenates containing AsO6 octahedra
'International Union of Crystallography (IUCr)', 2018Co-Authors: Karolina Schwendtner, Uwe KolitschAbstract:The crystal structures of hydrothermally synthesized (T = 493 K, 7 d) thallium(I) digallium arsenic(V) hexakis[hydrogenarsenate(V)], TlGa2As(HAsO4)6, caesium digallium arsenic(V) hexakis[hydrogenarsenate(V)], CsGa2As(HAsO4)6, and caesium Dialuminium arsenic(V) hexakis[hydrogenarsenate(V)], CsAl2As(HAsO4)6, were solved by single-crystal X-ray diffraction. The three compounds are isotypic and adopt the structure type of RbAl2As(HAsO4)6 (R\overline{3}c), which itself represents a modification of the RbFe(HPO4)2 structure type and consists of a tetrahedral–octahedral framework in which the slightly disordered M+ cations are located in channels. The three new compounds contain AsO6 octahedra assuming the topological role of M3+O6 octahedra. The As—O bond lengths are among the shortest As—O bond lengths known so far in AsO6 octahedra
Meisheng Xia - One of the best experts on this subject based on the ideXlab platform.
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dilithium Dialuminium trisilicate crystalline phase prepared from coal fly ash
Journal of Materials Engineering and Performance, 2012Co-Authors: Zhitong Yao, Meisheng XiaAbstract:The dilithium Dialuminium trisilicate phase Li2Al2Si3O10 was prepared using coal fly ash and lithium hydroxide monohydrate LiOH·H2O as precursors. The influences of various preparation conditions on Li2Al2Si3O10 forming were investigated. The results showed that the optimum additive amount of LiOH·H2O was about 20%. The onset of calcining temperature and time was identified as 980 °C and 1 h, respectively. XRD analysis indicated that the content of Li2Al2Si3O10 phase increased at the expense of quartz and mullite, with calcining temperatures increasing and time extending. SEM observation revealed that the calcined samples were drastically interlocked together with the prolonging of time. The obtained Li2Al2Si3O10 phase was well crystallized and with small grain size.