Christopher J. Ziegler

Research Interests

Our interests focus on coordination chemistry and understanding the synergistic relationships between metals and ligands in biomolecules and materials, including coordination polymers. While the coordination of small molecules to metal centers is relatively well understood, the effect of complex ligand environments is still an area of intense investigation. Our research examines metal ions in complex coordination environments, including tetrapyrrolic macrocycles and advanced materials.

Metalloporphyrins have been studied for more than a century and many researchers have probed the relationship between macrocycle structure and the metal center. However, the metal complexes of porphyrin isomers (such as porphycene or N-confused porphyrin), porphyrin analogs (such as corrole) and other pyrrolic macrocycles have not been as extensively studied. Not only are porphyrin isomers and analogs excellent potential ligands for transition metals, but these compounds also can be used to examine the effects of aromaticity and central pore size on metal structure and reactivity. Our research examines the metal complexes of novel polypyrrolic ligands, in part as an attempt to determine the reasons behind the natural selection of porphyrin as the tetrapyrrole of choice. We have published several reports on the fundamental chemistry of N-confused porphyrin.  In addition, we have begun to explore a family of phthalocyanine analogs known as the hemiporphyrazines.  As in N-confused porphyrin, the hemiporphyrazines can bind metal ions in unusual geometries.

We have also begun to explore the chemistry of organometallic complexes in aqueous systems.  Normally, organometallic bonds are highly sensitive to both dioxygen and water.  However, certain metal ions, especially those with d⁶ electron counts, can form complexes that are stable in aerobic aqueous conditions.  In particular, we are currently exploring the chemistry of compounds  containing the Re(CO)₃⁺ moiety.  This unit can be used to model the chemistry of next generation technetium drugs based on the Tc(CO)₃⁺ group; technetium is the most commonly used radionuclide in the clinic and there is a continuing need for new imaging agents based on this element.

Selected Publications

1. Franklin, B.R.; Herrick, R.S.; Ziegler, C.J.; Çetin, A.; Barone, N.; Condon, L.R.  "Reactions of the Re(CO)₃(H₂O)₃⁺ Synthon with Monodentate Ligands under Aqueous Conditions" Inorganic Chemistry, 2008, 47(13) 5902-5909.
2. Cetin, A.; Sripothongnak, S.; Wu, R. Durfee, W. S.; Ziegler, C. J. "Co(II) and Co(III) complexes of m-benziphthalocyanine" Chemical Communications, 2007, (41) 4289-4290.
3. Cetin, A.; Durfee, W. S.; Ziegler, C. J. "Low-Coordinate Transition Metal Complexes of a Carbon Substituted Hemiporphyrazine" Inorganic Chemistry, 2007, 46(16) 6239-6241. 
4. Wu, Q.; Cetin, A.; Durfee, W. S.; Ziegler, C. J. "Metal mediated C-H bond activation in a carbon substituted hemiporphyrazine" Angewante Chemie, 2006, 45(34) 5670-5673.
5. Herrick, R.S.; Brunker, T.J.; Maus, C.; Crandall, K.; Cetin, A.; Ziegler, C.J. "Aqueous preparation and physiological stability studies of Re(CO)₃(scorpionate) compounds" Chemical Communications, 2006, (41), 4330 - 4331.
6. Herrick, R.S.; Ziegler, C.J.; Cetin, A.; Brunker, T.J. "Structure of the triaquatricarbonylrhenium(I) cation and its conjugate base" European Journal of Inorganic Chemistry, 2007, (12)  1632-1634.
7. Hamilton, B. H.; Kelly, K. A.; Wagler, T. A.; Espe, M. P.; Ziegler C. J. "Lead Tetrakis(imidazolyl)borate solids: Anion exchange, solvent intercalation, and self assembly of an organic anion" Inorganic Chemistry, 2004, 43(1) 50-56.
8. Harvey, J. D.; Ziegler, C. J. "Developments in the metal chemistry of N-confused porphyrin" Coordination Chemistry Reviews, 2003, 247 (1-2) 1-19.
9. Harvey, J. D.; Ziegler, C. J. "CH bond activation and meso carbon reduction in manganese N-confused porphyrins" Chemical Communications, 2003,  (23) 2890-2891.
10. Harvey, J. D., Ziegler, C. J. "Dimeric and monomeric forms of manganese N-confused porphyrin" Chemical Communications, 2002, (17) 1942 - 1943.
11. Hamilton, B. H., Kelly, K. A. Wagler T. A., Espe, M. P., Ziegler, C. J. "The construction of a functional layered solid using the tetrakis(imidazolyl)borate coordinating anion" Inorganic Chemistry, 2002, 41(20) 4984-4986.
12. Hamilton, B. H., Ziegler C. J. "The structures of Cu(I) and Ag(I) coordination polymers using the tricyanofluoroborate anion" Chemical Communications, 2002, (8) 842-843.