Klaus Grohmann, Ph.D.
Professor (Emeritus) - Organic Chemistry
office 1401N (tel 212-772-5333), lab 1402N (tel 212-772-4637), dept fax 212-772-5332, email email@example.com
Ph.D. University of Heidelberg, Post-Doctoral Research: California Institute of Technology
The goal of our research is the synthesis and characterization of theoretically significant molecules. The results of their structural, chemical, and spectroscopic investigation will provide experimental tests for theoretical predictions as well as broaden our understanding of important concepts in organic chemistry. Most of our research centers around the various aspects of "aromaticity" or the lack of it. Some representative structures under investigation are shown below.
Semibullvalenes. The study of semibullvalenes, compounds which are characterized by the lowest activation energy for the Cope rearrangement, is aimed at further lowering this barrier until it becomes zero or negative, thus crossing the bridge between valence tautomerism (Eact>O) to resonance (Eact<O). A new general synthesis for substituted semibullvalenes has been developed.
13-Methylphenalene. This long sought after molecule and its benzo derivatives, possessing a rigid nearly planar 12n-perimeter, are expected to show a very strong paramagnetic ring current. Several synthetic approaches are under investigation.
Sulfur heterocycles/organic metals. The synthesis of heterocycles containing two or more sulfur units in conjugated 7- to 10-membered rings and in related polycyclic systems will be undertaken in order to determine th aromaticity as well as their reactivity with regard to sulfur extrusion and complex formation with transiti metals. The study of charge transfer complexes derived from these systems with respect to their potential as "organic metals" is part of our research program.
"Supramolecular squares of porphyrazines" Cheng, K.F., Thai, N.A., Teague, L.C., Grohmann, K., Drain, C.M. Chem. Commun. 2005, (37): 4678-4680
"Porphyrins linked directly to the 5,5 ' positions of 2,2 '-bipyridine: A new supramolecular building block and switch" Cheng, K.F., Drain, C.M., Grohmann, K. Inorg. Chem. 2003, 42 (6): 2075-2083.
"A Facile Entry into the Ring System of Sativene" Karimi, S., Petersen, B., Grohmann, K.G., (1998) Tetrahedron Letter 39, 2689
"1,2,5 Trithiepin: A 10pi Electron Heteroaromatic System" Ueng, S.N., Blumenstein, M., Grohmann, K.G., (1997) J. Org. Chem. 62, 2432
"Intramolecular Ring-Opening of Cyclopropanones by Enolate Anions," Karimi, S., Grohmann, K.G., and Todaro, L., (1995) J. Org. Chem. 60, 554
"2,4,6,8-Tetracarbomethoxybarbaralane,"Win, W. W. , Grohmann, K.G., and Todaro, L., (1994) J. Org. Chem. 59, 2803.
"Semibulivalenes IV: 2,6- and 2, 8-Trapping of the Bicyclo [13.3.0]octadienyl Diradical with Oxygen" lyengar, R., Pina, R., Grohmann, K.G. and Todaro, L., (1988) J. Amer. Chem. Soc. 110, 2643.
"Semibulivalenes II: A MNDO Theoretical Study of the Rearrangements of Semibullvalenes and Several of its Derivatives," Miller, L.S., Grohmann, K.G. and Dannenberg, J.J. (1983) Amer. Chem. Soc. 105, 6682.
"Semibullvalenes I: Synthesis and Crystal Structure of 1.5-Dimethyl-2, 4, 6, 8-tetracarbomethoxytricyclo [188.8.131.52] octa-3.6-diene - A Donor-Acceptor Substituted Semibullvalene," Miller, L.S., Grohmann, K.G., Dannenberg, J.J., Todaro, L. (1981) J. Amer. Chem. Soc. 103, 6249.