Tungsten (VI) oxychloride

Tungsten (VI) Oxychloride (WOCl₄) is an orange or red-orange crystalline material.  It is extremely air sensitive, reacting with both Oxygen and moisture.  It is a versatile precursor, and can be used to make a variety of Tungsten-based metal-organic complexes. It can also be used to incorporate Tungsten into silica-based materials.

For example, two researchers from the University of Turku and the University of Jyväskylä in Finland published work in which they used Tungsten oxytetrachloride to prepare a variety of coordination complexes with aminotris(phenolate) ligands.  The work was undertaken while developing metal-organic coordination compounds that could be used as catalysts for organic synthesis.

Tungsten-based catalytic organo-metallic complexes can also be incorporated into silica-based systems.  For example, a multi-national collaboration of researchers incorporated a Tungsten-based oxo imidazoline-2-iminato methyl precatalyst onto a silica support.  Tungsten Tetrachloride Oxide was used as the Tungsten precursor for synthetic preparation.  The material was then tested and found to be an effective catalyst for metathesis of terminal olefins such as propylene.

Besides catalysts, Tungsten (VI) Oxychloride can be incorporated into Tungsten other silica-based materials well.  Researchers from the National Taipei University of Technology in Taiwan used the precursor to prepare Vanadium Tungsten Silicate thin films of the formula V_1-x-yW_xSi_yO₂.  The films had thermochromic and thermo-optical properties that would make the material useful in sensors.

References:

1. Qureshi, Z. S., Hamieh, A., Barman, S., Maity, N., Samantaray, M. K., Ould-Chikh, S., Abou-Hamad, E., Falivene, L., D’Elia, V., Rothenberger, A., Llorens, I., Hazemann, J. L., & Basset, J. M. (2017). SOMC-Designed Silica Supported Tungsten Oxo Imidazolin-2-iminato Methyl Precatalyst for Olefin Metathesis Reactions. Inorganic Chemistry, 56(2), 861–871. https://doi.org/10.1021/ACS.INORGCHEM.6B02424
2. Gelbard, G., Mallek, J. L., & Girolami, G. S. (2014). Tungsten Oxytetrachloride and Several Tungstate Salts. Inorganic Syntheses, 36, 147–151. https://doi.org/10.1002/9781118744994.CH27
3. Arjun, N., Yang, T. C. K., Pan, G. T., Yang, Y. L., & Kareiva, A. (2016). The study of thermochromic and thermo-optical properties of sol–gel V1−x−y WxSiyO2 films by response surface method. Journal of the Taiwan Institute of Chemical Engineers, 69, 151–155. https://doi.org/10.1016/J.JTICE.2016.10.014
4. Lehtonen, A., & Sillanpää, R. (2005). Reactions of tris(ethanediolato)tungsten and tungsten oxytetrachloride with aminotris(phenol)s: Alkoxide, chloro, and alkyl derivatives of oxotungsten(VI) complexes with tetradentate [O3N]-type ligands. Organometallics, 24(11), 2795–2800. https://doi.org/10.1021/om050103w
5. Feil, S. E., Tyree, S. Y., Collier, F. N., McCarley, R. E., & Fleming, P. B. (2007). Tungsten Oxide Tetrachloride. Inorganic Syntheses, 9, 123–126. https://doi.org/10.1002/9780470132401.CH33