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Preparation, structural characterization, and thermal ammonolysis of two novel dimeric transition silylamide complexes

Cheng, Fei; Hope, Christopher N.; Archibald, Stephen J.; Bradley, John S.; Clark, Stephen; Francesconi, M. Grazia; Kelly, Stephen M.; Young, Nigel A.; Lefebvre, Frédéric

Authors

Fei Cheng F.Cheng@hull.ac.uk

Christopher N. Hope

John S. Bradley

Stephen Clark

Dr Nigel Young N.A.Young@hull.ac.uk
Senior Lecturer/ Director of Studies/ Deputy Head of Chemistry and Biochemistry/ Industrial Placements Coordinator

Frédéric Lefebvre



Abstract

The preparation and molecular structures of two novel dimeric transition metal silylamide complexes {Li0.5Zr[NHSi(NMe2)3]1.5[NSi(NMe2)3]0.5[μ -NSi(NMe2)3]}2 and {Li0.5Hf[NHSi(NMe2)3]1.5[NSi(NMe2)3]0.5[μ-NSi(NMe2)3]}2 with a tetrahedral coordination environment are reported. Thermal ammonolysis of  {Li0.5Zr[NHSi(NMe2)3]1.5[NSi(NMe2)3]0.5[μ-NSi(NMe2)3]}2 in an autoclave yields a mesoporous partially lithiated silicon zirconium imide powder Si3Zr(N)(NH)x(NH2)y(NMe2)z with a surface area of 440 m2/g. A microporous partially lithiated silicon hafnium imide powder Si3Hf(N)(NH)x(NH2)y(NMe2)z with a surface area of 232 m2/g was obtained via a similar ammonolysis process of {Li0.5Hf[NHSi(NMe2)3]1.5[NSi(NMe2)3]0.5[μ-NSi(NMe2)3]}2. Both of these silicon zirconium and hafnium imide powders have a disordered octahedral coordination environment. Pyrolysis of these zirconium and hafnium silicon imide powders leads to the formation of mixtures of porous zirconium or hafnium lithium silicon nitride ceramics with a regular octahedral coordination environment. They contain some residual lithium and exhibit a much reduced surface area due to an almost total collapse of the pores during the pyrolysis process.

Journal Article Type Article
Publication Date 2011-03
Journal INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
Print ISSN 1546-542X
Electronic ISSN 1744-7402
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 8
Issue 2
Pages 467-481
APA6 Citation Cheng, F., Hope, C. N., Archibald, S. J., Bradley, J. S., Clark, S., Francesconi, M. G., …Lefebvre, F. (2011). Preparation, structural characterization, and thermal ammonolysis of two novel dimeric transition silylamide complexes. International Journal of Applied Ceramic Technology, 8(2), 467-481. https://doi.org/10.1111/j.1744-7402.2009.02452.x
DOI https://doi.org/10.1111/j.1744-7402.2009.02452.x
Keywords Marketing; Materials Chemistry; Condensed Matter Physics; Ceramics and Composites
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