Assembly strategy of polyoxotungstates: nanosized clusters with non-conventional templates

Yan, Jun (2010) Assembly strategy of polyoxotungstates: nanosized clusters with non-conventional templates. PhD thesis, University of Glasgow.

Abstract

This thesis focuses on the assembly of non-conventional templated polyoxotungstates, specifically on the 6A group anions such as SO32-, SeO32- and TeO66-, which results in the discovery of 40 new polyoxotungstate compounds from the traditional Dawson-like cluster {SW18} to the nanoscale cluster {Se8W119} cluster. This study demonstrated that the identification and isolation of discrete building blocks to produce versatile and modular species can be assembled in a controlled manner, and it still represents a fundamental objective in the development of inorganic chemistry from the molecule to the nano world.
The assembly of Iso-polyoxotungstate fragments can be affected by a few key reaction variables including, but not limited to, pH, temperature, ionic strength, type of cations and solvents. Carefully screening and controlling the reaction conditions can result in the isolation of the different aggregate behaviour of building blocks such as {W11} units. Further, the use of synthetically innocent anions appears to be important in the assembly of Iso-polyoxtungstate with pentagonal units.
The Dawson-Like type X ⊂ {W18O54} (X= SIV, SeIV or TeVI) clusters can be reasonably designed and were isolated in a “one-pot” procedure by using a “shrink wrapping” strategy. These clusters are fully characterized by XRD, ESI-MS/CSI-MS and chemical analysis, IR, as well as by preliminary electrochemical studies. The effects of organo-cation, ionic strength and pH are investigated, especially in tungstoselenite and tungstotellurate chemistry. The synthetic methodology is also developed, the combination of building block strategy and solvent & cation exchange methods lead to the isolation of a series of new polyoxotungstate compounds including an “in-situ” reduction product {TeIVW18}, the thermochromic {Se2W18} cluster, and the organic soluble lacunary cluster {Se2W19}. These discoveries lead to a general new polyoxometalate building block approach and start a new field in polyoxotungstate synthesis.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: polyoxometalate, self-assembly, structual building units, polyoxotungstate, cryospray mass stectrometry, molecular engineering
• Subjects: Q Science > QD Chemistry; T Technology > TP Chemical technology
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Cronin, Prof. Lee and Long, Dr. De-Liang
• Date of Award: 2010
• Embargo Date: 13 October 2021
• Depositing User: Mr JUN YAN
• Unique ID: glathesis:2010-2179
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 02 Dec 2010
• Last Modified: 19 Apr 2020 07:59
• URI: https://theses.gla.ac.uk/id/eprint/2179