Well-defined surface imido amido tantalum(v) species from ammonia and silica-supported tantalum hydrides. Avenier, P., Lesage, A., Taoufik, M., Baudouin, A., Mallmann, A. D., Fiddy, S., Vautier, M., Veyre, L., Basset, J., Emsley, L., & Quadrelli, E. A. Journal of the American Chemical Society, 129(1):176–186, January, 2007.
Well-defined surface imido amido tantalum(v) species from ammonia and silica-supported tantalum hydrides. [link]Paper  doi  abstract   bibtex   
The MCM-41 supported hydrides [([triple bond]SiO)(2)TaH(3)], 1a, and [([triple bond]SiO)(2)TaH(3)], 1b, cleave N-H bonds of ammonia at room temperature to yield the well-defined imido amido surface complexes [([triple bond]SiO)(2)Ta(NH)(NH(2))], 2, and 2xNH(3). Additionally, the surface silanes [[triple bond]Si-H] that exist in close proximity to 1a and 1b also react with ammonia at room temperature to give the surface silylamido [Si-NH(2)]. Such reaction is tantalum assisted: surface silanes were synthesized independently and in absence of tantalum by reaction of highly strained silica, SiO(2-1000), with SiH(4) and no reaction with ammonia was observed. Surface-supported complexes 2, 2xNH(3), and [[triple bond]Si-NH(2)] have been characterized by, inter alia, solid-state NMR, IR, and EXAFS and independent synthesis of [[triple bond]Si-NH(2)]. The NMR studies on the fully 15N-labeled samples have led to unambiguous discrimination between imido, amido, and amino resonances of 2*, 2*x(15)NH(3), and [[triple bond]Si-15NH(2)] through the combination of solid-state magic angle spinning (MAS), heteronuclear correlation (HETCOR), 2D proton double-quantum (DQ) single-quantum (SQ) correlation, and 2D proton triple-quantum (TQ) single-quantum (SQ) correlation spectra. The in situ IR monitoring of the reaction of 1a and 1b with regular NH(3) and 15NH(3), and after H/D exchange has yielded the determination of all the NH(x) vibration and deformation modes, with their respective H/D and 14N/15N isotopic shifts. EXAFS study yielded the bond distances in 2 of 1.79(2) Angstrom for Ta=N, 1.89(1) Angstrom for Ta-O, and 1.98(2) Angstrom for Ta-N.
@article{Avenier2007,
	title = {Well-defined surface imido amido tantalum(v) species from ammonia and silica-supported tantalum hydrides.},
	volume = {129},
	issn = {0002-7863},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17199297},
	doi = {10.1021/ja0666809},
	abstract = {The MCM-41 supported hydrides [([triple bond]SiO)(2)TaH(3)], 1a, and [([triple bond]SiO)(2)TaH(3)], 1b, cleave N-H bonds of ammonia at room temperature to yield the well-defined imido amido surface complexes [([triple bond]SiO)(2)Ta(NH)(NH(2))], 2, and 2xNH(3). Additionally, the surface silanes [[triple bond]Si-H] that exist in close proximity to 1a and 1b also react with ammonia at room temperature to give the surface silylamido [Si-NH(2)]. Such reaction is tantalum assisted: surface silanes were synthesized independently and in absence of tantalum by reaction of highly strained silica, SiO(2-1000), with SiH(4) and no reaction with ammonia was observed. Surface-supported complexes 2, 2xNH(3), and [[triple bond]Si-NH(2)] have been characterized by, inter alia, solid-state NMR, IR, and EXAFS and independent synthesis of [[triple bond]Si-NH(2)]. The NMR studies on the fully 15N-labeled samples have led to unambiguous discrimination between imido, amido, and amino resonances of 2*, 2*x(15)NH(3), and [[triple bond]Si-15NH(2)] through the combination of solid-state magic angle spinning (MAS), heteronuclear correlation (HETCOR), 2D proton double-quantum (DQ) single-quantum (SQ) correlation, and 2D proton triple-quantum (TQ) single-quantum (SQ) correlation spectra. The in situ IR monitoring of the reaction of 1a and 1b with regular NH(3) and 15NH(3), and after H/D exchange has yielded the determination of all the NH(x) vibration and deformation modes, with their respective H/D and 14N/15N isotopic shifts. EXAFS study yielded the bond distances in 2 of 1.79(2) Angstrom for Ta=N, 1.89(1) Angstrom for Ta-O, and 1.98(2) Angstrom for Ta-N.},
	number = {1},
	journal = {Journal of the American Chemical Society},
	author = {Avenier, Priscilla and Lesage, Anne and Taoufik, Mostafa and Baudouin, Anne and Mallmann, Aimery De and Fiddy, Steven and Vautier, Manon and Veyre, Laurent and Basset, Jean-Marie and Emsley, Lyndon and Quadrelli, Elsje Alessandra},
	month = jan,
	year = {2007},
	pmid = {17199297},
	keywords = {\#nosource},
	pages = {176--186},
}

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