Research article:

Titanium-Oxide Host Clusters with Exchangeable Guests

Guanyun Zhang, Wenyun Li, Caiyun Liu, Jiong Jia, Chen-Ho Tung , and Yifeng Wang*
J. Am. Chem. Soc., DOI: 10.1021/jacs.7b10565

[Abstract] A novel family of water-soluble, polyoxocationic titanium-oxide host–guest clusters are reported herein. They exhibit an unprecedented hexagonal prismatic core structure for hosting univalent cationic guests like K+, Rb+, Cs+ and H3O+. Guest exchange has been studied using 133Cs NMR, showing the flexible pore of a host permits passage of a comparatively larger cation and giving an equilibrium constant of ca. 13 for displacing Rb+ by Cs+. Attractive ion-dipole interaction, depending on host–guest size complementarity, plays a dominant role for the preferential encapsulation of larger alkali-metal cationic guests. [View details......]

ACS Catal. Research Article
Iodine/Visible Light Photocatalysis for Activation of Alkynes for Electrophilic Cyclization Reactions
Yuliang Liu, Bin Wang, Xiaofeng Qiao, Chen-Ho Tung , and Yifeng Wang*
ACS Catal., 2017, 7, pp 4093–4099

[Abstract] Photocatalytic organic synthesis needs photocatalysts to initiate the reactions and to control the reaction paths. Available photocatalytic systems rely on electron transfer or energy transfer between the photoexcited catalysts and the substrates. We explore a concept based on the photopromoted catalyst coupling to the substrate and the phototriggered catalyst regeneration by elimination from the catalytic cycle. A catalytic amount of elementary I2 is applied as both a visible light photocatalyst and a π Lewis acid, enabling the direct activation of alkyne C≡C bonds for electrophilic cyclization reactions, one of the most important reactions of alkynes. Visible light is crucial for both the iodocyclization of the propargyl amide and the deiodination of the intermediate. Singlet oxygen is found to play a key role in the regeneration of I2. This system shows good functional group compatibility for the generation of substituted oxazole aldehydes and indole aldehydes. Hence, this study provides a readily accessible alternative catalytic system for the construction of heterocycle aldehyde derivatives by sunlight photocatalysis. [View more......]

Published in Inorganic Chemistry, 2016 Mar 05.

The article reports that weak adsorbents (universal in solutions) can substaintially affect the catalytic reactions of strong adsorbents in catalysis.


Inorganic Chemistry


Influence of Polyoxometalate Protecting Ligands on Catalytic Aerobic Oxidation at the Surfaces of Gold Nanoparticles in Water


Synopsis: The rate of gold nanoparticle (Au NP)-catalyzed aerobic (O2) oxidations of CO to CO2 increases as a linear function of the number of surface-bound metal−oxygen cluster anions, α-PW11O397− (polyoxometalates, or POMs), which, in turn, decrease the binding energies of electrons in Au 4f atomic orbitals at the nanoparticle surface. Hence, just as catalysis by metal(0) nanoparticles is influenced by metal oxide supports in heterogeneous catalysis, metal oxide cluster-anion ligands modify the reactivities of colloidal Au NPs in solution. [View more......]


Mingfu Zhang, Jingcheng Hao, Alevtina Neyman, Yifeng Wang*, and Ira A. Weinstock*
Inorg. Chem. 2016, DOI: 10.1021/acs.inorgchem.6b02167

Publication Date (Web): December 12, 2016




Chemoselective Claisen-​Schmidt bis-​substitutional condensation catalyzed by an alkoxy-​bridged dinuclear Ti(IV) cluster


ABSTRAACT: The highly efficient and chemoselective α,α′-bis-substitution of alkanones is important in organic synthesis. Herein, a dimeric titanium cluster, Ti2Cl2(OPri)6·2HOPri (Ti2), is used in the Claisen–Schmidt condensation reaction, for the selectively activation of symmetrical ketones containing α,α′-methylene groups and production of α,α′-bis-substituted alkanones in high efficiency and chemoselectivity. The high efficiency and chemoselectivity can be extended to a variety of typical alkanones and aromatic aldehydes. Both of the oxo-bridged dimeric motif of Ti2 and the ionic Ti–Cl bond are responsible for the high efficiency and chemoselectivity. [view more... ]


Yufei Wu, Jie Hou, Yuliang Liu, Mingfu Zhang, Chen-Ho Tung, Yifeng Wang
Tetrahedron, 2016, 72, pp 1511-1516
Publication Date (Web): January 30, 2016
DOI: org/10.1016/j.tet.2016.01.055

Inorganica Chimica Acta


Interfacial charge transfer in a functionalized polyoxotitanate cluster


ABSTRACT:Understanding the charge transfer processes at the dye/TiO2 interface is often modeled using catechol/TiO2 systems. However, it indeed require precise structural information. In order to simulate the dye/TiO2 systems at a molecular level, herein we report the synthesis and structure of a novel titanium oxo-cluster [Ti4O(OiPr)6(DTBC)4] (1) functionalized with 3,5-di-tert-butylcatechol (DTBC). UV–Vis spectroscopy, electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations show that 1 exhibits property of Ti(III) which is caused by substantial charge transfer from the π electrons of the benzene rings to Ti3d orbitals. The present precise structure and charge transfer mechanism help to better understand chromophore binding to semiconductor surfaces and charge transfer at the dye/TiO2 interfaces. [view more... ]


Jie Hou, Qun Zhang, Yufei Wu, Yuliang Liu, Lin Du, Chen-Ho Tung, Yifeng Wang
Inorganica Chimica Acta, 2016, 443, pp 279-283
Publication Date (Web): June 28, 2016
DOI: org/10.1016/j.ica.2016.01.017


Inorg. Chem.


A Post-Functionalizable Iso-Polyoxotitanate Cage Cluster


Synopsis: In the late stage of solvothermal synthesis of TiO2 nanocrystals, a host−guest 22-titanium oxo cluster encapsulating two guests, an I and an OH, is isolated. The surface of this novel compound can be postfunctionalizable with catecholate and carboxylate ligands. [view more... ]

Jie Hou, Junyi Hu, Qing Sun, Guanyun Zhang, Chen-Ho Tung, and Yifeng Wang
Inorg. Chem., 2016, 55 (14), pp 7075–7078
Publication Date (Web): June 28, 2016
DOI: 10.1021/acs.inorgchem.6b00982

Inorg. Chem.


Counteranion-Stabilized Titanium(IV) Isopolyoxocationic Clusters Isolated from Water


Synopsis: A new titanium(IV) oxo cluster comprised of only Ti, O, and H atoms, [Ti6(Oμ)8(OtH2)20]8+, was isolated from water and thoroughly characterized. This type of a relatively rare isopolyoxocationic cluster with no organic ligands is stabilized by hydrogen-bonded counteranions. [view more... ]


Guanyun Zhang, Jie Hou, Mingzhong Li, Chen-Ho Tung, and Yifeng Wang
Inorg. Chem., 2016, 55 (10), pp 4704–4709
Publication Date (Web): April 27, 2016
DOI: 10.1021/acs.inorgchem.5b01901

Inorg. Chem.


Small Titanium Oxo Clusters: Primary Structures of Titanium(IV) in Water


ABSTRACT: For sol–gel synthesis of titanium oxide, the titanium(IV) precursors are dissolved in water to form clear solutions. However, the solution status of titanium(IV) remains unclear. Herein three new and rare types of titanium oxo clusters are isolated from aqueous solutions of TiOSO4 and TiCl4 without using organic ligands. Our results indicate that titanium(IV) is readily hydrolyzed into oxo oligomers even in highly acidic solutions. The present clusters provide precise structural information for future characterization of the solution species and structural evolution of titanium(IV) in water and, meanwhile, are new molecular materials for photocatalysis. [View more... ]

Guanyun Zhang, Jie Hou, Chen-Ho, Tung and Yifeng Wang
Inorg. Chem., 2016, 55 (7), pp 3212–3214
Publication Date (Web): March 18, 2016
DOI: 10.1021/acs.inorgchem.6b00129




Inorg. Chem.


Effects of Substitutional Dopants on the Photoresponse of a Polyoxotitanate Cluster


Synopsis: Using 17 isostructural polyoxotitanates (POTs) as molecular models of doped titanium oxide nanoparticles, it has been revealed that lattice doping with transition metal ions may not be an efficient way, while loading of defect sites may be very effective for both photocatalysis and solar cells applications of titanium oxides. [View more...]

Junyi Hu, Lijie Zhan, Guanyun Zhang, Qun Zhang, Lin Du, Chen-Ho Tung, and Yifeng Wang
Inorg. Chem., 2016, 55 (17), pp 8493–8501
Publication Date (Web): August 25, 2016 (Article)
DOI: 10.1021/acs.inorgchem.6b01071

ACS Catal.


TiO2 Photocatalytic Cyclization Reactions for the Syntheses of Aryltetralones


ABSTRACT: This work focuses on a new strategy to overcome the overoxidation in heterogeneous TiO2 photocatalysis and to realize high-efficiency photosynthesis. We demonstrate that TiO2 photocatalysis can integrate C–C and C═O formation in a tandem manner to achieve efficient oxidative cyclization for the syntheses of aryltetralones. This protocol does not need any additive besides the inexpensive and/or recyclable TiO2, O2, and (solar) light. High yields with excellent diastereoselectivities are obtained for a wide scope of electron-rich substrates. Our findings demonstrate that in contrast to the conventional overoxidation, as long as the radical cations possess sufficient reactivity toward nucleophilic addition, single-electron transfer processes in TiO2 photocatalysis can be developed into a powerful tool to construct C–C bonds and even strained carbon rings. [View more...]


Yuliang Liu, Mingfu Zhang, Chen-Ho Tung, and Yifeng Wang*
ACS Catal., Articles ASAP (As Soon As Publishable), pp 8389–8394
Publication Date (Web): November 8, 2016 (Letter)
DOI: 10.1021/acscatal.6b03076

Inorg. Chem.


Alkali Halide Cubic Cluster Anions ([Cs8X27]19–, X = Cl, Br) Isolated from Water


Synopsis: A series of [Cs8X27]19− (X = Cl, Br) cubic cluster anions, which feature the structure of four unit cells of CsCl type, were obtained by precipitating the prenucleation octacesium chloride anionic clusters from water solutions and using [M4(OH)8(OH2)16]8+ (M = ZrIV or HfIV) as the counter cations to form intercluster compounds. [View more...]


Qing Sun, Guanyun Zhang, Chen-Ho Tung, and Yifeng Wang*
Inorg. Chem., 2016, 55 (21), pp 11125–11130
DOI: 10.1021/acs.inorgchem.6b01741
Publication Date (Web): October 24, 2016


J. Am. Chem. Soc.


Water-Soluble Pentagonal-Prismatic Titanium-Oxo Clusters


ABSTRACT: By using solubility control to crystallize the prenucleation clusters of hydrosol, a family of titanium-oxo clusters possessing the {Ti18O27} core in which the 18 Ti(IV)-ions are uniquely connected with μ-oxo ligands into a triple-decked pentagonal prism was obtained. The cluster cores are wrapped by external sulfate and aqua ligands, showing good solubilities and stabilities in a variety of solvents including acetonitrile and water and allowing their solution chemistry being studied by means of electrospray ionization mass spectroscopy, 17O NMR, and vibrational spectroscopy. Furthermore, this study provides new titanium oxide candidates for surface modifications and homogeneous photocatalysis. [view more...]


Guanyun Zhang, Caiyun Liu, De-Liang Long, Leroy Cronin, Chen-Ho Tung, and Yifeng Wang*
J. Am. Chem. Soc., 2016, 138 (35), pp 11097–11100
Publication Date (Web): August 15, 2016 (Communication)
DOI: 10.1021/jacs.6b06290


Journal article: Yifeng Wang, Dan Zhao, Hongwei Ji, Wanhong Ma, Jincai Zhao.* Sonochemical Hydrogen Production Efficiently Catalyzed by Au/TiO2. J. Phys. Chem. C., 2010, 114, 17728–17733.

Journal article: O. Snir, Yifeng Wang, M. E. Tuckerman, Y. V. Geletii, I. A. Weinstock.*  Concerted Proton−Electron Transfer to Dioxygen in Water. J. Am. Chem. Soc. 2010, 132 (33), 11678-11691.

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Address: School of chemistry, Shandong univerisity, Jinan, China