Matthew C. Asplund
BS, Brigham Young University (1992)
Ph.D., University of California at Berkeley (1998)
Postdoctoral Fellow, University of Pennsylvania (1998-2000)
The development of short-pulsed lasers has allowed for direct probing of chemical reactions in real time. Typically, one laser pulse is used to initiate a chemical reaction, and a second pulse is used to probe the intermediates or products some time later. Chemical reactions in condensed phases are especially well suited to these techniques, since the steps in the reactions occur very fast, usually on a time scale shorter than a nanosecond. My research focuses on the use of time-resolved techniques, both on the femtosecond/picosecond time scale, and on the longer nanosecond/microsecond time scale. Of particular importance is the use of infrared spectroscopy for probing chemical species, since it is easier to correlate with molecular structure than electronic spectroscopy.
Model Ring Formation Reactions: One area of particular interest in my lab is reactions involving organometallic species involved in the formation of new carbon-carbon bonds and the formation of rings. An interesting class of reactions is labeled Pauson-Khand reactions. In its most general form, it is the reaction of an alkene, and alkyne a carbonyl to form a 5-membered cyclopenteneone ring.
The reaction proceeds thermally, and in order to follow the reaction with time-resolved spectroscopic methods, we use a variant of the reactant that combines the alkene and alkyne in the same molecule.
The reaction mechanism shows that the first step is the removal of a CO from the Mo(CO)6, followed by formation of a complex between the Mo(CO)5 and the complex, followed by formation of the ring. We are trying to establish which part of the ligand attaches to the metal first.
Bi-metal catalyst systems: One of the difficulties in current catalytic systems is that they usually require use of a rare and expensive metal atom. There is tremendous interest in using bimetallic systems where the two atoms act cooperatively to give reactions that are similar to rare metals. While there are many catalytic reaction studies that have established the viability of this approach, there is little known about the details of the reactions. We are applying our transient infrared spectroscopy to these bi-metallic systems to try to understand how these cooperative systems drive chemistry.
C-F bond activation reactions: One are of particular interest in my lab is reactions involving organometallic species involved in catalytic bond breaking processes. Previous work on molecules which break C—H bonds in alkanes shows that the first photon dissociates a ligand from the metal center, and then this metal atom reacts with the surrounding alkane solvent molecule to form a alkyl hydride product, having broken a C—H bond in the alkane. Currently we are studying a related molecule that is able to break C—F bonds in perfluoro-benzene. This tungsten containing organometallic has a reaction between the W atom, and a tethered perfluorobenzene ring. Our recently published work showed that the rate of the reaction is limited by the formation of a weak complex with the solvent. We are able to measure the spectrum of this solvent complex on a nanosecond time-scale, and compare the spectrum directly with calculations.
Laser surface patterning: In my lab we are also research novel methods for using lasers to functionalize surfaces. Working with Dr. Matt Linford, we are using high intensity laser pulses to ablate, of remove, atoms from the surface of silicon wafers. The newly exposed Si atoms react rapidly with molecules in liquid placed on the surface. Using an array of micro-lenses, we have shown rapid functionalization and patterning of surfaces with alkyl halides, epoxides, amines and other chemically important groups. Our current setup allows for the creation of 2500 spots each with a diameter of 2-3 microns. These spots can be functionalized with DNA, proteins or other chemical or biochemical sensors.
F. Zhang, L. Pei, E. Bennion, G. Jiang, D. Connley, L. Yang, M. V. Lee, R. C. Davis, V. S. Smentkowski, G. Strossman, M. R. Linford, M. C. Asplund, Laser Activation Modification of Semiconductor Surfaces (LAMSS), Langmuir, In Press
M. C. Asplund, A. M. Johnson, J. A. Jakeman, Time-resolved infrared dynamics of C-F bond activation by a tungsten metal-carbonyl, Journal of Physical Chemistry B, 110, 20-24, 2006
Y. Y. Lua, W. J. J. Fillmore, L. Yang, M. V. Lee, P. B. Savage, M. C. Asplund, M. R. Linford, First reaction of a bare silicon surface with acid chlorides and a one-step preparation of acid chloride terminated monolayers on scribed silicon, Langmuir, 21, 2093-2097, 2005
L. W. Zilch, G. A. Husseini, Y. Y. Lua, M. V. Lee, K. R. Gertsch, B. R. Cannon, R. M. Perry, E. T. Sevy, M. C. Asplund, A. T. Woolley, M. R. Linford, Rapid and convenient method for preparing masters for microcontact printing with 1-12 micron features, Review of Scientific Instruments, 75, 3065-3067,2004
N. Agbonkonkon, H. D. Tolley, M. C. Asplund, E. D. Lee, M. L. Lee, Prediction of gas-phase reduced ion mobility constants (K-0), Analytical Chemistry, 76, 5223-5229, 2004
G. L. Jiang, T. L. Niederhauser, S. A. Fleming, M. C. Asplund, M. R. Linford, Evidence for a radical mechanism in monolayer formation on silicon ground (or scribed) in the presence of alkyl halides, Langmuir, 20, 1772-1774, 2004
T. Pan, R. T. Kellly, M. C. Asplund, A. T. Woolley, Fabrication of calcium fluoride capillary electrophoreseis microdevices for on-chip infrared detection,Journal of Chromatography A, 1027, 2004
Y. Y. Lua, M. V. Lee, W. J. J. Fillmore, R. Matheson, A. Sathyapalan, M. C. Asplund, S. A. Fleming, M. R. Linford, Amine-reactive monolayers on scribed silicon with controlled levels of functionality: Reaction of a bare silicon surface with mono- and di-epoxides, Angewandte Chemie-International Edition, 42, 2003
G. Husseini, J.G. Peacock,T.L. Niederhauser, M. C. Asplund, E. T. Sevy, M. R. Linford, PhotoChemical Lithography: Creation of patterned acid chloride functionalized surfaces by exposure to UV light. Langmuir 19, 4856-4858, 2003
Lua, Y.-Y.; Niederhauser; T.L.; Matheson, R.; Bristol, C.; Mowat, I.A.; Asplund, M.C.; Linford, M.R. Static Time-of-Flight Secondary Ion Mass Spectrometry of Monolayers on Scribed Silicon derived from 1-Alkenes, 1-Alkynes and 1-Haloalkanes. Langmuir, 18, 4840-4846, 2002
M. C. Asplund, P. T. Snee, J. S. Yeston, M. S. Wilkens, C. K. Payne, H. Yang, K. T. Kotz, H. Frei, R. G. Bergman, C. B. Harris, Ultrafast UV pump/IR probe studies of C-H activation in linear, cyclic and aryl hydrocarbons, Journal of the American Chemical Society 124, 10605-10612, 2002
Niederhauser, T. L.; Jiang, G.; Lua, Y.-Y.; Dorff, M. J.; Woolley, A. T.; Asplund, M. C.; Berges, D. A.; Linford, M. R.; A New Method of Preparing Monolayers on Silicon and Patterning Silicon Surfaces by Scribing in the Presence of Reactive Species, Langmuir, 17, 5889-5900, 2001
M. T. Zanni, M. C. Asplund, R. M.Hochstrasser, Two-dimensional heterodyned and stimulated infrared photon echoes of N-methylacetamide-D, J Chem Phys, 114, 4579-4590, 2001
M. C. Asplund, M. T. Zanni, R. M. Hochstrasser, Two Dimensional Infrared Spectroscopy of Peptides by Phase Controlled Femtosecond Vibrational Photon Echoes, Proceeding of National Academy of Science, 97, 8219-8224, 2000
R. M. Hochstrasser, M. C. Asplund, P. Hamm, N.-H. Ge, Femtosecond Two-Dimensional Infrared Spectroscopy, Journal of the Chinese Chemical Society, Presented at the Ultrafast Phenomena in Spectroscopy Conference, Taipei, Taiwan, October 1999
M. C. Asplund, M. Lim, R. M. Hochstrasser, Spectrally Resolved Three Pulse Photon Echoes in the Vibrational Infrared, Chemical Physics Letters, 323, 268-277, 2000
H. Yang, K. T. Kotz, M. C. Asplund, M. J. Wilkins, C. B. Harris, Ultrafast infrared studies of bond activation in organometallic complexes, Accounts of Chemical Research, 32, 551-560, 1999
M. C. Asplund, H. Yang, K. T. Kotz, S. E. Bromberg, M. J. Wilkens, C. B. Harris, Femtosecond infrared studies of chemical bond activation, Laser Chemistry, 19, 253-262, 1999
H. Yang, M. C. Asplund, K. T. Kotz, M. J. Wilkens, H. Frei, C. B. Harris, Reaction mechanism of silicon-hydrogen bond activation studied using femtosecond to nanosecond IR spectroscopy and ab initio methods, Journal of the American Chemical Society, 120, 10154-10165, 1998
S. E. Bromberg, H. Yang , M. C. Asplund, T. Lian, B. K. McNamara, K. T. Kotz, J. S. Yeston, M. Wilkens, H. Frei, Robert G. Bergman, C. B. Harris, The mechanism of a C-H bond activation reaction in room-temperature alkane solution, Science, 289, 260-263, 1997
H. Yang, K. T. Kotz, M. C. Asplund, C. B. Harris, Femtosecond Infrared studies of silane silicon-hydrogen bond activation, Journal of the Americal Chemical Society, 119, 9564-9565, 1997
T. Q. Lian, S. E. Bromberg, M. C. Asplund, H. Yang, C. B. Harris, Femtosecond infrared studies of the dissociation and dynamics of transition metal carbonyls in solution. Journal Of Physical Chemistry, Jul 18, 1996, 100, 11994-12001.