Loker Hydrocarbon Research Institute

Wed. May. 22, 2013

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Karl O. Christe

Research Professor of Chemistry

Office:	ACB 206
Phone:	(213) 740-3552
Fax:	(213) 740-6679
Email:	kchriste@usc.edu
	College Website

Research Focus

Our interests are very broad and range from very basic studies to applied research of academic, Government or industrial interest. We are particularly interested in high energy density materials (HEDM), inorganic main group chemistry, polynitrogen and nitramine chemistry, high-oxygen carriers, energetic ionic liquids, chemistry at the limits of oxidation and coordination, and the synthesis and characterization of novel carbocation and fluorocarbon compounds. Our work exploits the synergism of theory and synthesis and greatly benefits from close collaborations with numerous groups of theoreticians. The main goal of our research is to advance the state of the art and strive for spectacular break-throughs, rather than settling for small incremental improvements.

Typical examples of break-through achievements, achieved by us in the past, include the first syntheses of novel cations, such as NF₄⁺ [1] or ClF₆⁺ [2], which are derived from nonexisting parent molecules, the first chemical synthesis of elemental fluorine [3] which according to the textbooks was impossible, the synthesis of XeF₅^- [4] and IF₅² [5] which constitute the first examples of pentagonal planar AX5 species, the development of a synthesis for truly anhydrous soluble "naked" fluoride ion [6] which has led to a renaissance in high coordination number chemistry [7], the synthesis of N₅⁺ [8] which is the only stable polynitrogen species in more than 100 years and only the second known man-made polynitrogen preparable on a macroscopic scale, the spectroscopic identification of the cyclic N₅^- anion [9], the synthesis of the first oxygen-balanced energetic ionic liquids for liquid monopropellant applications [10], the preparation and characterization of over 40 new polyazides [11] and their combination with energetic counter-ions as for example in [N₅]⁺[B(N₃)₄]^- [12], and the developments of the first quantitative scales for oxidizer strengths [13] and Lewis acidities [14].

References

1.	"The Tetrafluoronitronium (V) Cation, NF₄⁺," K. O. Christe, J.P. Guertin, and A.E. Pavlath, Inorg. Nucl. Chem. Letters, 2, 83 (1966).
2.	"The Hexafluorochlorine (VII) Cation, ClF₆⁺," K. O. Christe, Inorg. Nucl. Chem. Letters, 8, 741 (1972).
3.	"Chemical Synthesis of Elemental Fluorine," K. O. Christe, Inorg. Chem., 25, 3721 (1986).
4.	"The Pentafluoroxenate (IV) Anion, XeF₅^-; the First Example of a Pentagonal Planar AX₅ Species," K. O. Christe, E. C. Curtis, H.P. Mercier, J. C. P. Sanders, G. J. Schrobilgen, and D. Dixon, J. Am. Chem. Soc., 113, 3351 (1991).
5.	"Pentagonal Planar AX₅ Species: Synthesis and Characterization of the Iodine (III) Pentafluoride Dianion, IF₅^2-," K. O. Christe, W.W. Wilson, G.W. Drake, D.A. Dixon, J.A. Boatz, and R.Z. Gnann, J. Am. Chem. Soc., 120, 4711 (1998).
6.	"Syntheses, Properties, and Structures of Anhydrous Tetramethylammonium Fluoride and its 1:1 Adduct with trans-3-Amino-2-Butene Nitrile," K. O. Christe, W. W. Wilson, R. D. Wilson, R. Bau, and J. Feng, J. Am. Chem. Soc., 112, 7619 (1990).
7.	"Heptacoordinated Main-Group Fluorides and Oxyfluorides," K. O. Christe, E.C. Curtis, D.A. Dixon, H.P.A. Mercier, J.C.P. Sanders, G.J. Schrobilgen, and W.W. Wilson, Chapter 5 in "Inorganic Fluorine Chemistry Toward the 21st Century" ACS Symposium Series 555 (1994).
8.	"N₅⁺: A Novel Homoleptic Polynitrogen Ion as a High Energy Density Material," K. O. Christe, W. W. Wilson, J. A. Sheehy, and J. A. Boatz, Angew. Chem. Int. Ed., 38, 2004 (1999).
9.	“Experimental Detection of the Pentaazacyclopentadienide (Pentazolate) Anion, cyclo-N₅^-,” A. Vij, J. G. Pavlovich, W. Wilson, V. Vij, and K. O. Christe, Angew. Chem. Int. Ed., 41, 3051 (2002),.
10.	“Oxygen Balanced Energetic Ionic Liquid,” C. J. Bigler Jones, R. Haiges, T. Schroer, and K. O. Christe. Angew. Chem. Int. Ed., 2006, published on line.
11.	“Experimental Evidence for Linear Metal-Azide Bonds. The Binary Group 5 Azides Nb(N₃)₅, Ta(N₃)₅, [Nb(N₃)₆]^- and [Ta(N₃)₆]^-, and 1:1 Adducts of Nb(N3)5 and Ta(N₃)₅ with CH₃CN,” R. Haiges, J. A. Boatz, T. Schroer, M.Yousufuddin, and K. O. Christe, Angew. Chem. Int. Ed., 45, 4830 (2006) and references cited therein.
12.	“New High Energy Density Materials. Synthesis and Characterization of N₅⁺P(N₃)₆^-, N₅⁺B(N₃)₄^-, N₅⁺HF₂^-_nHF, N₅⁺BF₄^-, N₅⁺PF₆^-, and N₅⁺SO₃F^-,” R. Haiges, S. Schneider, T. Schroer, and K. O. Christe, Angew. Chem. Int. Ed., 43, 4919 (2004),.
13.	"A Quantitative Scale for the Oxidizing Strength of Oxidative Fluorinators," K. O. Christe and D.A. Dixon, J. Am. Chem. Soc., 114, 2978 (1992) .
14.	"A Quantitative Scale for Lewis Acidities Based on Absolute Fluoride Ion Affinities," K. O. Christe, D. A. Dixon, and D. McLemore, J. Am. Chem. Soc., to be published.