The Catholic University of America

Dr. Leopold May
Professor Emeritus
Physical, Spectroscopy, History of Chemistry



                                   B.ChE, 1944, College of the City of New York.
                                   M. S., 1949, Ph. D., 1951, Polytechnic Institute of Brooklyn.
                                   Exchange Scientist, Academies of USA and USSR, 1976-1977; 1978. 
                                   Sr. Fulbright Lecturer, 1980.
                                   Fellow, Society for Applied Spectroscopy, 2008

 Tel:     (202) 319-5392


Summary of Research Interests

One of the research efforts in our laboratory has been devoted to the interpretation of spectroscopic measurements on a variety of chemical systems including europium, iron, and tin complexes, biochemicals, minerals and alloys. The primary type of spectroscopy used in this research is Mössbauer (or nuclear gamma resonance) spectroscopy, valuable for identifying oxidation and spin states and bonding of metal ions in complexes. Since 1985 with Dr. George Eng of University of the District of Columbia and his group, we have been studying the speciation of tributyltin and triphenyltin compounds in the sediments of the rivers in the vicinity of Washington and the Chesapeake Bay by measuring the Mössbauer spectra of the compounds directly within the sediments. This has been extended to components of sediments, such as clays and sand. With Dr. Clive I. Wynter of the Nassau Community College and his colleagues, we have doing research on the dynamic structure of europium compounds as well as its fluorescence properties. Another project is the measurement of the ferrous and ferric composition of American Indian Pottery and other ceramic materials.

Another research done in conjunction with Dr. John Golin of the Biology Department is concerned with the efflux of drugs from yeast. We have related the efflux of various substrates including tri-<em>n</em>-alkytin chlorides and tetraalkyltins to properties such as molecular volume, hydrophobicity, and distance between the tin and carbon atoms. Unexpectedly, the extent of efflux was not related to the hydrophobicity of the substrate but to its surface volume. We have found that there are three sites at which the substrates interact with the Pdr5 depending upon the properties of the substrate. Mutants are being prepared to aid in determining the natures of these sites.  For a recent review of this research, see Golin, et al., 2007.

  Research into the history of chemistry led to the collection of the birthdays of prominent chemists and the listing of significant chemical events, which is used by This Week in Chemical History published by the American Chemical Society. Historical events in spectroscopy may be viewed at Monthly Historical Events in Spectroscopy. Biographies of selected chemists and physicists are found at the History Corner. Also, a listing of historical events in Mössbauer Spectroscopy can be found here. An informal association of those devoted to propagating the music of chemist-composers has been formed- Society for the Propagation of the Music of the Chemist-Composers.

Visit the Hall of Chemical History in Maloney Hall by viewing the video "Tour of the Hall of Chemical History" prepared by Ms. Adrienne Black, Assistant to the Chairman of the Chemistry Department.

Some Recent  Publications

The yeast Pdr5p multidrug transporter: How does it recognize so many substrates?" Golin, J.; May, L.; Ambudkar, S. Biochem. Biophys. Res. Commun., 2007, 356, 1-5.

"Synthesis, spectroscopic characterization and X-ray crystal and molecular structures of diphenyltin(IV) complexes of acetone Schiff bases of S-alkyldithiocarcarbzates", Akbar Ali, M.; Mirza, A. H.; Hamid, M. H. H. A.; Bernhardt, P. V.; Atchade, O.; Song, X.; Eng, G.: May, L., Polyhedron, 2008, 27, 977-984.

"The lesser known chemist-composers, past and present," May, L. Bull. Hist. Chem., 2008, 33, 35-43.

"In celebration of the 50th anniversary of SAS: a brief history of the early years," Margoshes, M.; May, L., The SAS Spectrum Newsletter, 2008,

."In celebration of the 50th anniversary of SAS: a selection of ground breaking papers from Applied Spectroscopy," May, L.; Chase, B.; Griffiths, P.; Harris, J., The SAS Spectrum Newsletter, 2008,

"The early years of SAS," Margoshes, M.; May, L., Appl. Spectrosc., SAS 50th Yr. Spec. Ed., 2008, 5-14.

"A selection of ground breaking papers published in Applied Spectroscopy," May, L.; Chase, B.; Griffiths, P.; Harris, J., Appl. Spectrosc., SAS 50th Yr. Spec. Ed., 2008, 36-52.

"Mössbauer spectroscopy of 151europium dicarboxylates," Wynter, C. I.; Ryan, D. H.' Trichtchenko, O.; Voyer, C. J.; Brown, D. E.; Sobel, S. G.; Haigney. A. L.; May, L.; Hillery, B. R.; Gajbhiye, N. S., Hyperfine Inter., 2008, 185, 123-127.

"Mutations define cross-talk between the n-terminal nucleotide-binding domain and transmembrane helix-2 of the yeast multidrug transporter Pdr5: Possible conservation of a signaling interface for coupling ATP hydrolysis to drug transport," Sauna, Z. E.; Bohn, S. S.; Rutledge, R.; Dougherty, M. P.; Cronin, S.; May, L.; Xia, D.; Ambudkar, S. V.; Golin, J., J. Biol. Chem., 2008, 283, 35010-35022.