Joyce Y. Corey
Professor
Corey received her Ph.D. degree at the University of Wisconsin
following a B.S. and M.S. at the University of North Dakota.
She has held visiting faculty positions at the University
of Wisconsin,
and the Universite des Sciences et Techniques du Languedoc. She
has been at UM-St. Louis since 1968 and assumed emeritus status
in 2008..
corey@umsl.edu
Office: B318
Phone: (314) 516-5360
Fax: (314) 516-5342
Research
Interests
Unlike CH bonds in hydrocarbon chemistry, the SiH bond in hydrosilanes
may be viewed as a functional group. However, transformations of SiH
to other Si-element bonds usually require a catalyst. Typical coreactants
are HE1 species and if E1 represents another silicon unit, then homodehydrocoupling
occurs to give silicon oligomers and polymers with H2 as
the only by-product. Titanium triad complexes are particularly effective
for this transformation. Silicon analogs of substituted ethanes, propanes
and butanes can be formed through the reaction of secondary silanes
such as PhMeSiH2 in the presence of the combination, Cp2MCl2 (M = Ti, Zr, Hf) and n-BuLi. With the availability of this simple dehydrogenative
coupling reaction, the chemistry of short chains can be studied and
developed. Examples include the removal of phenyl groups in H(PhMeSi)xH
with l to x equivalents of triflic acid to give the corresponding silyl
triflates, H[(Ph)x-y(OTf)ySixMex]H.
Replacement of the triflate group by reaction with a number of nucleophiles
may then take place to provide new oligomers. Oligomers with fluorosilane
end groups have also been prepared through reaction with CuF2 or CuCl2/KF/KI.
Condensation of primary silanes with metallocene halides plus RLi provides
polysilanes whose molecular weights vary with the structure of the metallocene.
The mechanism for this condensation process is not entirely clear but
probably involves sigma-bond materials steps and possibly radical processes.
Strategies that will lead to an increase in molecular weight are under
study and include modification of the basic metallocene structure as
well as the development of new catalyst systems. Although earlier reports
suggested that syndiotactic polysilanes were produced from metallocene
catalysts, our recent studies have demonstrated that this is not the
case and that the polymers are atactic. New challenges are to find catalysts
that improve the molecular weights and control the microstructure of
the polymer. Dehydrocoupling has also been utilized to generate polystannanes
from hydrostannanes as well as carbosilanes from systems of the general
formula, H3Si-X-SiH3.
The general reaction of hydrosilanes with other H-element bonds is a
general process promoted by a variety of transition metals. This transformation
proceeds by a mechanism that differs from the nucleophilic processes
at SiCl bonds that are usually employed for substitution at silicon.
As an example, hydrosilanes couple with alcohols in the presence of
Cp2TiCl2/n-BuLi. In the presence of transition
metal complexes hydrosilanes are also useful reducing agents for organic
substrates. An example includes hydrosilylation of ketones that can
be promoted in the presence of Cp2TiF2
Selected publications
"Activation of Group 14 El-H Bonds at Platinum(0)", C. P. White, J. Braddock-Wilking, J. Y. Corey, H. Xu, E. Redekop, S. Sedinkin, and N. P. Rath, Oganometallics 2007, 26, 1996.
"Si-H Bond Activation by (Ph3P)2Pt(h2-C2H4) in Dihydrosilicon Tricycles that Also Contain O and N Heteroatoms," J. Braddock-Wilking, J. Y. Corey, L. M. French, E. Choi, V. J. Speedie, M. F. Rutherford, S.Yao, H, Xu and N. P. Rath, Organometallics, 2006, 25, 3974.
"Spectroscopic and Reactivity Studies of Platinum-Silicon Monomers and Dimers," J. Braddock-Wilking, J. Y. Corey, K. A. Trankler, H. Xu, L. M. French, N. Praingam, C. White and N. P. Rath, Organometallics, 2006, 25, 2859.
"Reaction of Diphenylgermane with (Ph3P)2Pt(h2-C2H4): Generation of Mono- and Dinuclear Complexes Containing Pt-Ge Bonds. X-ray Crystal Structure Determination of [(Ph3P)Pt(m-h2-H-GePh2)]2," J. Braddock-Wilking, J. Y. Corey, C. White, H. Xu and N. P. Rath, Organometallics, 2005, 24, 4113.
"Reaction of Silafluorenes with (Ph3P)2Pt(h2-C2H4): Generation and Characterization of Pt-Si Monomers, Dimers, and Trimers," J. Braddock-Wilking, J. Y. Corey, K. A. Trankler, K. M. Dill, L. M. French and N. P. Rath, Organometallics, 2004, 23, 4576.
"Dehydrocoupling of hydrosilanes to polysilanes and silicon oligomers: A 30 year overview," J. Y. Corey, Adv. Organomet. Chem., 2004, 51, 1.
"Halide induced epimerization of meso-1,2-dihalo-1,2-diaryl-1,2-dimethyldisilanes" K. A. Trankler, J. Y. Corey and N. P. Rath, J. Organomet. Chem., 2003, 686, 66.
" Formation and X-ray Crystal Structure Determination of a Novel Triplatinum Cluster, ([(Ph3P)Pt(m-SiC12H8)]3 from Reaction of Silafluorene with (Ph3P)2Pt(h2-C2H4)," J. Braddock-Wilking, J. Y. Corey, K. Dill and N. P. Rath, Organometallics, 2002, 21, 5467.
"Amino-functionalized zirconocene C5H4CH(Me)NMe2)2ZrCl2, a catalyst for the dehydropolymerization of PhSiH3 Probing of peripheral substituent effects on catalyst dehydropolymerization activity," B. J. Grimmond and J. Y. Corey, Inorg. Chem. Acta., 2002, 330, 89 .
"Preparation of F(ArSiMe)2F and Observation of Crystallization-Induced Asymmetric Transformation in meso-rac-F(ArSiMe)2F and Anion-Induced Epimerization of meso-F(ArSiMe)2F'," K. A. Trankler, D. S. Wyman, J. Y. Corey, E. E. Katz and N. P. Rath, Organometallics, 2002, 20, 5139.
"Dehydrocoupling Reactions
of Hydrosilanes with Group 4 Metallocenes Cp2MY2 (M
= Ti, Zr, Hf; Y = F, OPh, NMe2)," Q. Wang and J. Y. Corey, Can.
J. Chem., 2000, 78, 1434.
"The Synthesis of Polysilanes by the Catalytic Dehydropolymerisation of Hydrosilanes," G.
M. Gray and J. Y Corey, in"Silicon Containing Polymers: The Science and Technology
of Their Synthesis and Applications," edited by R. Jones, J. Chojnowski and W.
Andro, Kluwer Academic Publishers, Dordrecht, 2000, Chap. 14,
371.
"The Synthesis and Characterization of Atactic Poly(p-Tolysilane) via the Catalytic
Dehydrocoupling of p-Tolylsilane," B. J. Grimmond and J. Y. Corey, Organometallics, 2000, 19,
3776.
"Enantiopure Siloxy-Functionalized Group 4 Metallocene Dichlorides. Synthesis,
Characterization and Catalytic Dehydropolymerization of PhSiH3," B.
J. Grimmond, N. P. Rath and J. Y. Corey, Organometallics, 2000, 19, 2975.
"Preparation of F(ArMeSi)2F and Isomerization of the Diastereomers," K.
A. Trankler, D. S. Wyman, J. Y. Corey, and E. E. Katz, Organometallics, 2000, 19,
2408.