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Rick Geier, Associate Professor of Chemistry; Department Chair

Contact Information
Mail: 211 Wynn Hall
Office: Chemistry
Phone: 315 2286795
Email: ggeier@colgate.edu

Department Affiliation
Chemistry

Degree
B.A. (Chemistry and Biology), 1992, Luther College
Ph.D. (Chemistry), 1997, University of Washington

Professional Experience
Visiting Scholar, Rensselaer Polytechnic Institute, 2004; Research Assistant Professor, North Carolina State University, 1999-2000; Postdoctoral Research Associate, North Carolina State University, 1997-1999

Specialities
Organic chemistry, molecular nanotechnology

Research Interests

Research in the Geier laboratory is directed towards investigation of methodology for the preparation of a variety of porphyrinoids.  Successful syntheses of porphyrinic species facilitate studies of macrocycle properties—such as stability, spectroscopy, metal binding, and catalysis.

Porphyrins perform diverse functions in Nature (Figure 1).  For example, the characteristic red color of blood and green color of plants are due to porphyrinoids (heme and chlorophyll respectively).  The rich diversity of porphyrin function arises from the variety of mechanisms available for the fine tuning of macrocycle properties.  The identity of the central metal ion and axial ligands are important.  The protein matrix surrounding the porphyrin ring also influences macrocycle properties.  And of particular interest to our research group, the core structure of the porphyrin can be substituted, reduced, heteroatom modified, isomerized, expanded, and/or contracted relative the prototypical porphyrin structure.

Structural alterations to the porphyrin macrocycle give rise to a large family of molecules that display diverse and complementary properties (Figure 2).  Some of the general structures shown in Figure 2 are found in Nature.  Others have been created in the laboratory in an effort to produce porphyrinoids of fundamental interest, and materials useful for a wide range of commercial applications including molecular electronic devices, solar energy, photodynamic cancer therapy, ion selective sensors, and catalysis. 

In the Geier research group, we have a number of ongoing projects involving many of the macrocycles shown in Figure 2.  Presently, we are exploring the series of compounds shown in Figure 3.  The central core of the porphyrinoids differ in subtle, but profound ways which may impact metal binding and properties of the metal chelates.  To forward these efforts, our group has contributed methodology for the preparation of corroles (J. Org. Chem. 2004, 69, 4159-4169), phlorin (J. Org. Chem. 2007, 72, 4084-4092), and 5-isocorrole (J. Org. Chem. 2010, 75, 553-563).  The phlorin prepared by our group is noteworthy as it is one of the most stable phlorins known towards degradation in light and air.  Preliminary metal binding experiments have been successfully carried out on a 5-isocorrole in collaboration with the Ziegler group at The University of Akron (Dalton Trans. 2011, 40, 4384-4386).  Further investigation of the coordination chemistry of these porphyrinoids, and studies of catalysis mediated by the metalloporphyrinoids are ongoing.  We also continue to target additional novel porphyrinoids in our synthetic investigations.

Throughout our studies, we utilize a broad range of experimental techniques including preparative organic synthesis, parallel analytical-scale reactions, analytical chromatographic methods (GC, HPLC) and preparative chromatography, and a variety of spectroscopic tools (NMR, UV-vis, IR, fluorimetry, EI-MS, CI-MS, and LD-MS).

Please make an appointment with Professor Geier to discuss current research opportunities in the Geier laboratory.

Further Readings

Excellent reviews of many topics germane to this research may be found in The Porphyrin Handbook, Kadish, K.M.; Smith, K.M.; Guilard, R., eds. Academic Press, 2000. and in The Colours of Life. Milgrom, L. R., Oxford University Press:  New York, 1997.

Publications

  • Costa, R.; Geier, G. R., III; Ziegler, C. J. “Structure and Spectroscopic Characterization of Free Base and Metal Complexes of 5,5-Dimethyl-10,15-bis(pentafluorophenyl)isocorrole,” Dalton Trans. 2011, 40, 4384-4386.
  • Flint, D. L.;* Fowler, R. L.;* LeSaulnier, T. D.;* Long, A. C.;* O’Brien, A. Y.; Geier, G. R., III “Investigation of Complementary Reactions of a Dipyrromethane with a Dipyrromethanemonocarbinol Leading to a 5-Isocorrole,” J. Org. Chem. 2010, 75, 553-563.
  • Braaten, K. C.;* Gordon, D. G.;* Aphibal, M. M.;* Geier, G. R., III “Effect of Carbinol Group Placement on Complementary Reactions of Dipyrromethane + Bipyrrole Species Leading to Corrole and/or an Octaphyrin,” Tetrahedron 2008, 64, 9828-9836.
  • O’Brien, A. Y.; McGann, J. P.;* Geier, G. R., III “Dipyrromethane + Dipyrromethanedicarbinol Routes to an Electron Deficient meso-Substituted Phlorin with Enhanced Stability,”  J. Org. Chem. 2007, 72, 4084-4092.
  • LeSaulnier, T. D.;* Graham, B. W.;* Geier, G. R., III “Enhancement of Phlorin Stability by the Incorporation of meso-Mesityl Substituents,” Tetrahedron Lett. 2005, 46, 5633-5637.
  • Geier, G. R., III; Grindrod, S. C.* “Meso-Substituted [34]Octaphyrin(1.1.1.0.1.1.1.0) and Corrole Formation in Reactions of a Dipyrromethanedicarbinol with 2,2'-Bipyrrole,” J. Org. Chem. 2004, 69, 6404-6412.
  • Geier, G. R, III; Chick, J. F. B;* Callinan, J. B.;* Reid, C. G.;* Auguscinski, W. P.* “A Survey of Acid Catalysis and Oxidation Conditions in the Two-Step, One-Flask Synthesis of meso-Substituted Corroles via Dipyrromethane-Dicarbinols and Pyrrole,”J. Org. Chem. 2004, 69, 4159-4169.
  • Chevalier, F.; Geier, G. R., III; Lindsey, J. S. “Acidolysis of Intermediates Used in the Preparation of Core-Modified Porphyrinic Macrocycles,” J. Porphyrins Phthalocyanines, 2002, 6, 186-197.
  • Geier, G. R., III; Callinan, J. B.;* Rao, D. P.; Lindsey, J. S. “A Survey of Acid Catalysts in Dipyrromethanecarbinol Condensations Leading to meso-Substituted Porphyrins,” J. Porphyrins Phthalocyanines, 2001, 5, 810-823.

Asterisks indicate undergraduate student co-authors who conducted their research in collaboration with a faculty member at Colgate.

Dissertation
The Preparation of a Metalloporphyrin-Peptide Conjugate Artificial Protein for the Catalytic Oxidation of Alkenes