Joseph W. Bruno, Ph.D. Professor of Inorganic & Organometallic    Chemistry and Dean, Natural Sciences and Mathematics       (860) 685-2649     jbruno@wesleyan.ed

    Ketenes are of interest because: a) they have been postulated as intermediates in the conversion of synthesis gas (CO/H₂) to oxygen-containing products; and b) they are highly unsaturated and potentially able to undergo several sequential bond-forming transformations. Ketenes are able to bind transition metals via at least two modes, involving either C=C or C=O p complexation. We have focused on the latter, and are interested in understanding the mechanism by which such bound ketenes undergo C=C cleavage to CO and carbene (R₂C:). Also, we not that C=O complexation of unsymmetrical ketenes is highly selective, and that nucleophilic attack can be used in the formation of E enolate isomers.

    Other research has centered on the syntheses and luminescence spectroscopy of organocerium (III) compounds. We have prepared strerically accessible compounds of this large lanthanide ion (which has a ground electronic state of 4f1), and found that they all luminesce from a 4f-5d excited state. Since cerium 5d orbitals figure prominently in metal-ligand bonding, the wave-lengths of the luminescent emissions vary significantly (over a range of 300nm) with the nature of the ligand sphere. This will allow the use of cerium (III) as a sensitive luminescent probe of metal binding sites in complex media, and as an indicator of the nature of the metal ligand bonding.
 

Selected Publications

• "Facile Synthesis of a,b-Unsaturated Niobium Acyls via g-Hydride Abstraction" Hneihen, A. S.; Fermin, M. C; Maas, J. J.; Bruno, J. W. J. Organomet. Chem. 429, C33-C37 (1992).
• "FT-IR Analysis of Toluene Hydrogenation Reactions on Reduced Alumina-Supported Catalysts" DeCanio, E. C.; Storm, D. A.; Bruno, J. W. Progress in Catalysis, 231 (1992).
• "Equilibrium Acidities of Some Transition Metal Acyl Compounds" Fermin, M. C.; Thiyagarajan, B.; Bruno, J. W. J. Am. Chem. Soc.115, 974 (1993).
• "Activation of Niobocene-Ketene Complexes: Ligand-Centered Syntheses of Hydrides and Acyls" Fermin, M. C.; Hneihen, A. .; Maas, J. J; Bruno, J. W. Organometallics 12, 1845 (1993).
• "MAS ¹H NMR Characterization of g-Alumina and Modified g-Aluminas" DeCanio, E. C.; Edwards, J. C.; Bruno, J. W. J. Catal. 148, 76 (1994).
• "Luminescence Studies of Cerium(III) Incorporated in Silica Gels Prepared Using Sol-Gel Methods" Rand, E. R.; Smuckler, M. B.; Go, E.; Bradley, M. S.; Bruno, J. W. Inorg. Chim. Acta 233, 71 (1995).
• "Synthesis, Structure, and Redox Reactivity of a Substituted Niobocene Formaldehyde Complex. The Importance of Hydrogen-Bonding in the Redox Chemistry" Thiyagarajan, B.; Michalczyk, L.; Bollinger, J. C.; Huffman, J. C.; Bruno, J. W. Organometallics 15, 1989 (1996).
• "Generation of Organoniobium(II) Radicals and Synthesis of Heterometallic Niobium-Mercury Compounds" Thiyagarajan, B.; Michalczyk, L.; Bollinger, J. C.; Bruno, J. W. Organometallics 15, 2588 (1996).
• "Electrophilic Attack on the Carbon Terminus of a Niobium-Bound Formaldehyde Ligand" Thiyagarajan, B.; Kerr, M. E.; Bollinger, J. C.; Young, V. G., Jr.; Bruno, J. W. Organometallics 16, 1331 (1997).
• "Synthesis and Reactivity of Niobium-Vinylketene Complexes Exhibiting Ketene C,O Complexation" Kerr, M. E.; Bruno, J. W. J. Am. Chem. Soc. 119, 3183 (1997).
• "Effects of the Niobium(V) Center on the Energetics of Ligand-Centered Proton and Hydrogen Atom Transfer Reactions in Acyl and Alkoxide Complexes" Kerr, M. E.; Zhang, X.-M.; Bruno, J. W. Organometallics 16, 3249 (1997).
• "Niobium-Mercury Hetermetallic Compounds as Sources of Niobium(II): Radical Paths to Organoniobium Species," Thiyagarajan, B.; Michalczyk, L.: Young, V.G., Jr.; Bruno, J.W. Organometallics 16, 5884 (1997).
• "Hydride Affinities of Arylcarbenium Ions and Iminium Ions in Dimethyl Sulfoxide and Acetonitrile," Zhang, X.-M.; Bruno, J.W.; Enyinnaya, E. J. Org. Chem. 63, 4671 (1998).
• "Thermodynamic and Kinetic Studies of Hydride Transfer for a Series of Molybdenum and Tungsten Hydrides," Sarker, N.; Bruno, J.W.; J. Am. Chem. Soc. 121, 2174 (1999).
• "Hydride and Proton Transfer Reactions of Niobium-Bound Ligands. Synthetic and Thermodynamic Studies of Ketene, Enacyl and Vinylketene Complexes," Kerr, M.E.; Sarker, N.; Hneihen, A.S.; Schulte, G.S.; Bruno, J.W. Organometallics 2000, 19, 901-912.
• "Process for High Temperature Production of Organic Aerogels," Mendenhall, R.; Andrews, G.; Bruno, J.W.; Albert, D.F., U.S. Patents 6,077,876 and 6,090,861, 2000.
• "Use of Niobium(III) and Niobium(V) Compounds in Catalytic Imine Metathesis under Mild Conditions," Bruno, J.W.; Li, X.J. Organometallics 2000, 19, 4672-4674.
• "Thermodynamic Studies of Hydride Transfer for a Series of Niobium and Tantalum Compounds," Sarker, N.; Bruno, J.W. Organometallics  2001, 20, 55-61.
• "Supercritical Methanol Drying as a Convenient Route to Phenolic-Furfural Aerogels," Albert, D.F.; Andrews, G.R.; Mendenhall, R.S; Bruno, J.W. J. Non-Cryst. Solids  2001, 296, 1-9.
• "Chelating Aryloxide Ligands in the Synthesis of Niobium, Tantalum, and Titanium Compounds," Michalczyk, L.; de Gala, S.; Bruno, J.W. Organometallics  2001, 20, 5547-5556.

• “Sterically-Congested Bisphosphite Ligands for the Catalytic Hydrosilation of Ketones,” Smith, A.R.; Bruno, J.W.; Pastor, S.D. Phosphorus, Sulfur, Silicon 2002, 177, 479-485.

• “Hydricities of BzNADH, C₅H₅Mo(PMe₃)(CO)₂H, and C₅Me₅Mo(PMe₃)(CO)₂H in Acetonitrile,” Ellis, W. W.; Raebiger, J. W.; Curtis, C. J.; Bruno, J. W.; DuBois, D. L. J. Amer. Chem. Soc.  2004,  126,  2738-2743.

Education

B.A. 1978 Augustana College

M.S. 1979 Northwestern University

Ph.D. 1983 Northwestern University

[Chemistry] [Wesleyan]

Last updated: January, 2002 (JB)