Title: Professor, Inorganic and Theoretical Chemistry
Office: SZ 501
Phone: (252) 328-9759
Army High Performance Computing Research Center (1992-1994)
Postdoctoral Fellow, Minnesota Supercomputer Institute (1991-1992)
Ph.D., Texas A&M University (1991)
B.A., The Colorado College (1985)
Much of the emphasis in our research group involves the application of accurate quantum chemical methods to the analysis of molecular systems. Two systems are currently garnering the bulk of our attention, and they are briefly described below.
Crown ether compounds are well known for their ability to selectively bind metal ions in the electron-rich pocket of the macrocycle. Interest in these systems stems, in part, from their enzyme-like specificity and their potential application as ion transport and sequestering agents of radionuclides in the treatment of streams contaminated by nuclear waste or heavy metal ions. Collaborators in the research group of Dr. John Sibert at the University of Texas at Dallas have recently derivatized the standard crown ether moiety with a redox-active substituent that is positioned to directly participate in host-guest interactions. These new molecules, dubbed Wurster’s crowns for their structural relationship to the well-known Wurster’s reagent (N,N,N’,N’-tetramethyl-p-phenylenediamine), have demonstrated numerous interesting properties, and our group is applying accurate computational methods to investigate the role of the redox-active moiety in metal-ion binding for both the neutral and oxidized species. Future work will involve the analysis of macrocycles with multiple redox centers and/or nitrogen and sulfur donor atoms, and will probe their application in chemical sensing, heavy-metal ion transport and redox-switchable catalysis.
Rhodium catalyzed hydroacylation effects the rapid synthesis of cyclopentanones, which are important intermediates in a variety of pharmaceuticals. A simple catalytic cycle of the process is shown in the accompanying schematic. Bosnich (Fairlie, D.P.; Bosnich, B. Organometallics 1988, 7, 946-954) attempted a detailed examination of the reaction mechanism using deuterium-labeling studies, but was thwarted by the overall complexity of the reaction and a lack of isolable intermediates. In this context, we are applying accurate computational methods to the analysis of the catalytic mechanism.
"Dimerization and Anion Binding of a Fluorescent Phospholipid Analogue," D. M. Jessen, A. N. Wercholuk, B. Xiong, A. L. Sargent, W. E. Allen, J. Org. Chem. 2012, 77, 6615-6619.
"Binding of Carboxylic Acids by Fluorescent Pyridyl Ureas," L.M. Jordan, P.D. Doyle, A.L. Sargent, W.E. Allen, J. Org. Chem. 2010, 75, 8450-8456.
"Wurster-Type' Ureas as Redox-Active Receptors for Anions," J. P. Clare, A. Statnikov, V. Lynch, A. L. Sargent, J. W. Sibert, J. Org. Chem. 2009, 74, 6637-6646.
"Fluorous Effects in Amide-Based Receptors for Anions," J. V. Gavette, J. M. McGrath, A. M. Spuches, A. L. Sargent, W. E. Allen, J. Org. Chem. 2009, 74, 3706-3710.
"Hydrogen Bonding vs Steric Gearing in a Hexasubstituted Benzene," J. V. Gavette, A. L. Sargent, W. E. Allen J. Org. Chem. 2008, 73, 3582-3584.
"Mechanism of Rhodium-Catalyzed Intramolecular Hydroacylation: A Computational Study," I. F. D. Hyatt, H. K. Anderson, A. T. Morehead Jr., A. L. Sargent, Organometallics 2008, 27, 135-147.
"On the Oxidation of Wurster's Reagent and the Wurster's Crown Analog of 15-Crown-5 in the Presence of Alkali Metal Cations," M. DeBacker, M. Hureau, M. Depriester, A. Deletoille, A. L. Sargent, P. B. Forshee, J. W. Sibert, J. Electroanal. Chem. 2008, 612, 97-104.
"Wurster's Crowns: A Comparative Study of ortho- and para-Phenylenediamine-Containing Macrocyclic Receptors," J. W. Sibert, P. B. Forshee, G. R. Hundt, A. L. Sargent, S. G. Bott, V. Lynch, Inorg. Chem. 2007, 46, 10913-10925.
"An Interactive Computer Program to Help Students Learn Molecular Symmetry Elements and Operations," D. E. Meyer, A. L. Sargent, J. Chem. Educ. 2007, 84, 1551-1552.
"A Theoretical Investigation on the Wurster's Crown Analogue of 18-Crown-6," A. L. Sargent, B. J. Mosley, J. W. Sibert, J. Phys. Chem. A 2006, 110/10, 3826-3837.
"Wurster's Crownophanes: An Alternate Topology for para-Phenylenediamine-Based Macrocycles," J. W. Sibert, G. R. Hundt, A. L. Sargent, V. Lynch, Tetrahedron 2005, 61/52, 12350-12357.
"Participation of Host 'Spacer' Atoms in Carboxylic Acid Binding: Implications for Amino Acid Recognition," D. K. Barnhill, A. L. Sargent, W. E. Allen, Tetrahedron 2005, 61/35, 8366-8371.
"Dynamic Disorder and Conformer Exchange in the Crystalline Monomer of Polycarbonate," J. E. Wolak, J. Knutson, J. D. Martin, P. Boyle, A. L. Sargent, J. L. White, J. Phys Chem. B 2003, 107, 13293-13299.
"Global vs. Local Aromaticity in Porphyrinoid Macrocycles: Experimental and Theoretical Study of 'Imidacene,' an Imidazole-Containing Analogue of Porphycene," A. L. Sargent, I. C. Hawkins, W. E. Allen, H. Liu, J. L. Sessler, C. J. Fowler, Chem. Eur. J. 2003, 9, 3065-3072.
"C-S and C-H Bond Activation of Thiophene by Cp*Rh(PMe3): A DFT Theoretical Investigation," A. L. Sargent and E. P. Titus, Organometallics, 1998, 17, 65-77.
"Electronic Structure of Axially Ligated Rhodium Carboxylates: pi Back-Bonding Revisited," A. L. Sargent, M. E. Rollog and C. T. Eagle, Theor. Chem. Acc., 1997, 97, 283-288.
"Poly(Thienyl)Borates: An Investigation Into the Coordination of Thiophene and Its Derivatives," A. L. Sargent, E. P. Titus, C. G. Riordan, A. L. Rheingold and P. Ge, Inorg. Chem., 1996, 35, 7095-7101.
"Enzyme-Catalyzed Enolization Reactions: A Theoretical Study on the Energetics of Concerted and Stepwise Pathways," A. L. Sargent, M. E. Rollog, J. Almlof, P. G. Gassman and J. Gerlt, J. Molec. Struct. (THEOCHEM), 1996, 388, 145-159.
"Massively Parallel Algorithms for Electronic Structure Calculations in Quantum Chemistry," A. L. Sargent, J. Almlof and M. W. Feyereisen, in Applications on Advanced Architecture Computers, G. Astfalk, Ed., Vol. 1, 1996, 1-13.
"Electron Delocalization in Helical Bis(quinone) Anion Radicals," A. L. Sargent, J. Almlof, and C. A. Liberko, J. Phys. Chem., 1994, 98, 6114-6117.
"Massively Parallel Algorithms for Electronic Structure Calculations in Quantum Chemistry," A. L. Sargent, J. Almlof, and M. W. Feyereisen, SIAM News, 1993, 26(1), 14.
"Theoretical Studies of Inorganic and Organometallic Reaction Mechanisms. 4. The Oxidative Addition of Dihydrogen to d8 Square-Planar Iridium Complexes With Trans Phosphines," A. L. Sargent and M. B. Hall, Inorg. Chem., 1992, 31, 317-321.
"Theoretical Studies of Inorganic and Organometallic Reaction Mechanisms. 3. The Origin of the Difference in the Barrier for the Kinetic and Thermodynamic Products for the Oxidative Addition of Dihydrogen to a Square-Planar Iridium Complex," A. L. Sargent, M. B. Hall, and M. F. Guest, J. Am. Chem. Soc., 1992, 114, 517-522.
"The Oxidative Addition of H2 to d8 Square-Planar Iridium Complexes," A. L. Sargent and M. B. Hall, in Topics in Physical Organometallic Chemistry, Vol. 4, M. Gielen, Ed., Freund Pub.: London, England, 1992; pp 1-39.
"Basis Sets for Geometry Optimizations of Second-Row Transition Metal Inorganic and Organometallic Complexes," Sargent, A. L.; Hall, M. B. J. Comp. Chem. 1991, 12, 923‑933.
"Linear Semibriding Carbonyls - 3. Carbonyl and Thiocarbonyl Ligands as Four‑Electron Donors," Sargent, A. L.; Hall, M. B. Polyhedron, 1990, 15/16, 1799‑1808.
"Linear Semibridging Carbonyls - 2. Heterobimetallic Complexes Containing a Coordinatively Unsaturated Late Transition Metal Center," Sargent, A. L.; Hall, M. B. J. Am. Chem. Soc. 1989, 111, 1563‑1569.