This is a project in collaboration with Prof. Michael Bowers at UCSB (current ACS award winner in Physical Chemistry!) and funded by the Air Force Office of Scientific Research (AFOSR). See the Bowers group website at http://bowers.chem.ucsb.edu.
We are currently collaborating with Prof. Peter Stang and his group at the University of Colorado. The motivation for this collaboration is the characterization of coordination-based supramolecular assemblies for which x-ray structures are not known in general. Ion mobility mass spectrometry is able to achieve this goal Rectanglar and triangular structures have been thoroughly studied and the results published . Two supramolecular structures are much larger in cross-section and currently being studied. We hope to obtain structural information consistent with their known x-ray structures and, since they are rigid molecules, use them for calibrating our theoretical calculations for large molecules.
Another goal of this current research effort is to continue interfacing the ongoing synthetic program at Edwards AFB on polyhedral oligomeric silsesquioxane (POSS) with the structural characterization capabilities of the Bowers group at UCSB. I recently completed a National Research Council Senior Associateship with the Bowers group doing ion mobility mass spectrometry, data analysis and computer modeling of POSS structures and am continuing the work on an active AFOSR grant.
POSS family of molecules have recently become of great interest due to their
inherent thermal stability and their ability to improve the thermal, physical
and chemical properties of host polymer systems. Mass spectrometric-based methods have been
recently developed to both identify and structurally characterize POSS and POSS
containing materials. These methods use
ion mobility to experimentally obtain molecular shapes and extensive molecular
mechanics/molecular dynamics calculations to generate detailed structural
information consistent with experiment.
Initial studies on well characterized POSS cages yielded structures
virtually identical with X-ray structures.
The Bowers group is currently collaborating with synthetic groups at
both Edwards AFB and at the
E. R. Brocker, S. E. Anderson, B. H. Northrop, P. J. Stang, and M. T. Bowers, "Structures of Metallosupramolecular Coordination Assemblies Can Be Obtained by Ion Mobility Spectrometry-Mass Spectrometry," J. Am. Chem. Soc., 132, 13486, (2010).
S. E. Anderson, A. Somogyi, T. S. Haddad, E. B. Coughlin, G. Gadodia, D. F. Marten, J. Ray, and M. T. Bowers, "ESI and MALDI Mass Spectrometry of Large POSS Oligomers," Int. J. Mass Spectrom. 292, 38, (2010).
S. E. Anderson, D. J. Bodzin, T. S. Haddad, J. A. Boatz, J. M. Mabry, C. Mitchell, and M. T. Bowers, “Structural Investigation of Encapsulated Fluoride in Polyhedral Oligomeric Silsesquioxane Cages Using Ion Mobility Mass Spectrometry and Molecular Mechanics,” Chem. Mater., 20, 4299, (2008).
S. E. Anderson, E. S. Baker, T. S. Haddad, C. Mitchell, and M. T. Bowers, “Structure of Hybrid Polyhedral Oligomeric Silsesquioxane Polymethacrylate Oligomers Using Ion Mobility Mass Spectrometry and Molecular Mechanics,” Chem Mater., 17, 2537 (2005).
E. S. Baker, J. Gidden, S. E.
E. S. Baker, J. Gidden, D. P. Fee, P.R. Kemper, S. E. Anderson, and M.T. Bowers, “3-dimensional structural characterization of cationized polyhedral oligomeric silsesquioxanes (POSS) with Styryl and phenylethyl capping agents,” Int. J. Mass Spectrom, 227, 205 (2003).
J. Gidden, P.R. Kemper, E. Shammel, D. Fee, S. E. Anderson, and M.T. Bowers, “Application of ion mobility to the gas-phase conformational analysis of polyhedral oligomeric silsesquioxanes (POSS)," Int. J. Mass Spectrom, 222, 63 (2003).
(website to download PDF files requires on-line access to journals) or click on 2012.pdf, 2010b.pdf, 2010.pdf, 2008.pdf, 2006.pdf, 2005.pdf, 2004.pdf, 2003a.pdf, 2003b.pdf for the above references or click on 1997_1.pdf, 1999_1.pdf, 1999_2.pdf, 1999_3.pdf, 2000_1.pdf, 2000_2.pdf, 2002_1.pdf, 2004_1.pdf, 2004_2.pdf, and 2004_3.pdf for additional general polymer papers published by the Bowers group.
We were involved in developing simple inexpensive
instrumentation for the measurement of stratospheric ozone since 1993. The goal
has been to set up a worldwide network which can monitor ozone accurately. Trends in
M. Morys, F. Mims III,
(click to download manuscript PDF file)