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Start Over Author "Bu, Xianhui" Journal journal of the american chemical society
138 results on '"Bu, Xianhui"'

8. Hydrothermal synthesis and structural characterization of zeolite-like structures based on gallium and aluminum germanates

Author

Bu, Xianhui, Feng, Pingyun, Gier, Thurman E., Zhao, Dongyuan, and Stuckyk, Galen D.

Subjects
Zeolites -- Research, Gallium -- Research, Aluminum -- Research, Chemistry
Abstract

Research was conducted to examine the hydrothermal synthesis and structural characterization of zeolite-like structures based on gallium and aluminum germanates. A novel class of germanate zeolite structures were prepared with inorganic cations or organic amines as structure-directing agents. The successful synthesis of several gallo- and aluminogermanate zeolite-like structures represents an important breakthrough in the synthesis of Ge-based 4-connected 3D framework structures.

Published
1998

9. Syntheses and characterization of chiral tetrahedral cobalt phosphates with zeolite ABW annd related frameworks

Author

Feng, Pingyun, Bu, Xianhui, Tolbert, Sarah H., and Stucky, Galen D.

Subjects
Cobalt -- Research, Zeolites -- Research, Chemistry
Abstract

The syntheses and characterizations of chiral tetrahedral cobalt phosphate compounds: MCoPO4 (M=Na, K, NH4, Rb) as well as the different types of framework structures have been described. One of the structures has the same topology as the zeolite ABW framework and the other cobalt phosphate can be viewed as a hybrid of tridymite and ABW frameworks. The cobalt phosphate compounds can be synthesized under hydrothermal conditions and their frameworks are more flexible than aluminosilicate in adapting cations of different sizes.

Published
1997

12. Largest Molecular Clusters in the Supertetrahedral TnSeries

Author

Wu, Tao, Wang, Le, Bu, Xianhui, Chau, Victoria, and Feng, Pingyun

Abstract

Supertetrahedral Tnclusters are exact fragments of cubic ZnS-type lattice and are often formed in situas building units for the construction of 3-D open-framework chalcogenide materials. Small Tnclusters can also be synthesized in discrete forms, allowing them to exist as soluble species in solution. In addition to their tunable electronic and optical properties, these soluble clusters can be used as precursors for the synthesis of porous semiconducting and optical materials. However, the synthesis of large Tnclusters is a significant challenge, and for several decades prior to this work, the size of the discrete Tncluster remained at T3, with only 10 metal sites (e.g., [Cd10S4(SPh)16]4−and [M5Sn5S20]10−, M = Zn, Co). Here we report a family of discrete chalcogenide T4 clusters ([MxGa18−xSn2Q35]12−, x= 2 or 4; M = Mn, Cu, Zn; Q = S, Se) whose discovery resulted from an unusual phase transformation from a 3-D T4 covalent framework into 0-D T4 molecular clusters. The driving force for such a transformation is the perfect match in both charge density and geometry between chalcogenide clusters and protonated amine, leading to the higher stability of isolated clusters. The perfect match is achieved by using complex quaternary compositions to maximize charge tunability of the cluster. These T4 clusters are the largest molecular Tnclusters known to date and can be made in various compositions showing tunable band structures in both solution and solid state.

Published
2024
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20. Templated assembly of sulfide nanoclusters into cubic-C3N4 type framework

Author

Bu, Xianhui, Zheng, Nanfeng, Li, Yuqi, and Feng, Pingyun

Subjects
Photoluminescence -- Research, Sulfide minerals -- Research, Chemistry
Abstract

Dibutylamine (DBA) has been capable of directing the formation of the cubic-C3N4 type topology. UCR-8Znlns-DBA is found to exhibit a strong photoluminescent emission centered at 470nm when excited at 410 nm.

Published
2003

21. Pushing up the size limit of chalcogenide supertetrahedral clusters: two- and three-dimensional photoluminescent open frameworks from (Cu5In30S54)(super 13-) clusters

Author

Bu, Xianhui, Zheng, Nanfeng, Li, Yuqi, and Feng, Pingyun

Subjects
Tetrahedra -- Atomic properties, Tetrahedra -- Structure, Particles, Cluster analysis, Chemistry
Abstract

The synthesis of UCR-16 and -17 has led to the creation of supertetrahedral clusters with unprecedented size and composition. Increasing size of supertetrahedral clusters represents a step forward toward bringing the size gap between colloidal nanoparticles and small clusters such as T2 and T3.

Published
2002

22. alpha-iminocarboxamidato-nickel(II) ethylene polymerization catalysts

Author

Lee, Bun Yeoul, Bazan, Guillermo, Vela, Javier, Komon, Zachary J.A., and Bu, Xianhui

Subjects
Catalysts -- Research, Polymerization -- Research, Chemistry
Abstract

It has been established that borane attachment to a site removed from the ethylene insertion trajectory can be used to activate nickel catalysts for olefin polymerization. There were found to be similarities in structure/reactivity relationships to Brookhart's diimine catalysts.

Published
2001

29. Boratabenzene complexes of Cr

Author

Rogers, Jonathan, S., Bu, Xianhui, and Bazan, Guillermo.

Subjects
Benzene -- Research, Borates -- Research, Chemistry
Abstract

Monoboratabenzene-Cr(III) compounds are found to be readily accessible by reaction with Ph3Cr(THF)3 or CrMe3.

Published
2000

30. Novel germanate zeolite structures with 3-rings

Author

Bu, Xianhui, Feng, Pingyun, and Stucky, Galen D.

Subjects
Zeolites -- Research, Cyclic compounds -- Research, Ring formation (Chemistry) -- Methods, Chemistry
Abstract

The limited success in the formation of silicate-based 3-ring structures may be due to the short Si-O bond distance and the corresponding large T-O-T angles that do not favor the highly stressed 3-ring configuration relative to rings of bigger sizes. To produce new 3-ring structures, the geometrical factors for reducing the stress found in a 3-ring structure have to be considered. The first 3-ring-containing germanates have been synthesized and their structures are shown.

Published
1998

31. Na2Zn3(CO3)4.3H2O, a microporous sodium zincocarbonate with a diamond-type tetrahedral-triangular topology

Author

Gier, Thurman E., Bu, Xianhui, Wang, Sue-Lein, and Stucky, Galen D.

Subjects
Carbonates -- Research, Sodium compounds -- Research, Organic compounds -- Research, Chemistry
Abstract

The synthesis, crystal growth and single crystal structure of a microporous sodium zincarbonate is reported. The open framework structure is characterized by a diamond-type tetrahedral-triangular topology and prepared as a microcrystalline powder by slowly adding NaHCO3 to ZnCl2. The crystals are stable in air and moisture but dissolve in dilute acid. Its asymmetric unit has two crystallographically different carbon and sodium atom sites.

Published
1996

39. Multilevel-Regulated Metal–Organic Framework Platform Integrating Pore Space Partition and Open-Metal Sites for Enhanced CO2Photoreduction to CO with Nearly 100% Selectivity

Author

Zheng, Hui-Li, Zhao, Jian-Qiang, Sun, Ya-Yong, Zhang, An-An, Cheng, Yu-Jia, He, Liang, Bu, Xianhui, Zhang, Jian, and Lin, Qipu

Abstract

Rational design and regulation of atomically precise photocatalysts are essential for constructing efficient photocatalytic systems tunable at both the atomic and molecular levels. Herein, we propose a platform-based strategy capable of integrating both pore space partition (PSP) and open-metal sites (OMSs) as foundational features for constructing high-performance photocatalysts. We demonstrate the first structural prototype obtained from this strategy: pore-partitioned NiTCPE-pstp(TCPE = 1,1,2,2-tetra(4-carboxylphenyl)ethylene, pstp= partitioned stptopology). Nonpartitioned NiTCPE-stpis constructed from six-connected [Ni3(μ3–OH)(COO)6] trimer and TCPE linker to form 1D hexagonal channels with six coplanar OMSs directed at channel centers. After introducing triangular pore-partitioning ligands, half of the OMSs were retained, while the other half were used for PSP, leading to unprecedented microenvironment regulation of the pore structure. The resulting material integrates multiple advanced properties, including robustness, wider absorption range, enhanced electronic conductivity, and high CO2adsorption, all of which are highly desirable for photocatalytic applications. Remarkably, NiTCPE-pstpexhibits excellent CO2photoreduction activity with a high CO generation rate of 3353.6 μmol g–1h–1and nearly 100% selectivity. Theoretical and experimental studies show that the introduction of partitioning ligands not only optimizes the electronic structure to promote the separation and transfer of photogenerated carriers but also reduces the energy barrier for the formation of *COOH intermediates while promoting CO2activation and CO desorption. This work is believed to be the first example to integrate PSP strategies and OMSs within metal–organic framework (MOF) photocatalysts, which provides new insight as well as new structural prototype for the design and performance optimization of MOF-based photocatalysts.

Published
2023
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