Department of Medicinal and Biological Chemistry

A. Alan Pinkerton, Ph.D.

Photo of Dr. A. Alan Pinkerton
  Professor

  Department of Medicinal and Biological Chemistry
  BO 2024
  Phone: 419.530.7902
  E-mail: a.pinkerton@utoledo.edu

 

AREA OF RESEARCH

Lanthanides and actinides. Synthetic routes have been developed to unusual lanthanide and actinide complexes with sulfur donor ligands containing phosphorus. The softness of the donor atoms enhances the covalent contribution to bonding to these hard metal ions. The complexes have been characterized by single crystal X-ray diffraction in the solid state and by NMR in solution. The observation of nuclear spin-spin coupling to 89-Y and through UO(2++) has been interpreted in terms of both sigma and pi contributions to the bonding. Hyperfine interactions have been derived from the NMR spectra (see below) of the paramagnetic complexes, which give information on electron-spin delocalization.

The work is currently being expanded to other sulfur donors, to other oxidation states of the lanthanides and actinides, and to organometallic compounds. The object of this study is to prepare new compounds in order to determine the influence of soft donor ligands on the stability and reactivity of the various oxidation states and of the organometallics, and to further characterize their bonding. The tools used will be X-ray diffraction, and solution and solid state NMR. Theoretical calculations are being carried out to characterize the orbitals involved in bonding and the mechanism for the transfer of spin to the ligands (hyperfine interactions).

Nuclear magnetic resonance. Our interest in NMR focuses on three major topics: i) Diamagnetic complexes in solution exhibit spin-spin coupling between 31-P and some metal nuclei, which gives us information about the intervening bonds. In other cases we are able to observe coupling between different phosphorous nuclei through the metal center which provides another bonding parameter; ii) Many lanthanide and actinide ions have unpaired f-electrons and are thus paramagnetic. We have developed methods to interpret the drastic effects these ions have on the NMR spectra of ligands. We thus obtain information concerning solution structures and a measure of spin delocalization expressed as the hyperfine coupling constant; iii) With the information available from solution NMR and solid state X-ray studies, we are now investigating NMR properties of these complexes in the solid in order to have an experimental link between solid state structures and those in solution.

X-Ray crystallography. The use of X-ray crystallography to solve chemical problems is well developed. We have structural interests in a wide variety of molecules. These studies are carried out on compounds we have prepared ourselves (see above), and on compounds prepared by other groups either within this department or as part of an international collaboration. Current studies involve small organic and organometallic molecules, drug structures, models of drug receptor sites, and natural products. Using a combination of X-ray diffraction and neutron diffraction we are able to determine charge density in the bonding region of small molecules. Current studies examine the metal-metal bond in a series of related organometallics, the deformation of pi-electron density due to pyramidalized sp2 carbon in a series of organic molecules, and the charge-density distribution in high energy (explosive) molecules. The study will be extended to map the electrostatic potential around molecules.

Educational Background

Maitre Assistant/Privat Docent Universite de Lausanne (Switzerland), 1978-84
Premier Assistant Universite de Lausanne (Switzerland), 1976-78
Chercheur invite Faculte des Sciences, Universite de Nice (France), 1974-76
  Universite de Lausanne (Switzerland), 1972-74
Postdoctoral Fellow University of Sussex (England), 1971-72
Ph.D. University of Alberta (Canada), 1971
Graduate Royal Institute of Chemistry, Brighton Polytechnic (England), 1966

Publications and Journals

  1. Dollimore, D., A. Martin and A.A. Pinkerton. (1996) A study of the thermal decomposition of biguanidinium diperchlorate using thermogravimetry and mass spectroscopy. Thermochim. Acta 285, 109-117.
  2. Pinkerton, A.A., C. leDrian and P. Vogel. (1996) Torturing the 7-oxabicyclo[2.2.1]heptane skeleton with an oxetane ring: structure of 4,7-dioxatricyclo[3.2.1.0-2,4]octane at 190 K. Acta Crystallogr. C52, 2927-2929.
  3. Guidi, A., V. Theurillat-Moritz, P. Vogel and A.A. Pinkerton. (1996) Enantiomerically pure Diels-Alder adducts of maleic anhydride to furfural acetals through thermodynamic control. Single crystal and molecular structure of (1S,4R,4'S,5'S)-1-(4',5'-dimethyldioxolan-2'-yl)-5,6-dimethylidenei-7-oxabicyclo[2.2.1]hept-2-ene. Tetrahed. Asymm. 7, 3153-3162.
  4. Li, J., K.V. Katti, A.A. Pinkerton, H. Nar and R.G.Cavell. (1996) Synthesis and characterization of phosphinimine-substituted trifluoro- or trichloro-p-benzoquinones and their cationic Rh(I) complexes. The crystal and molecular structure of 3,5,6-trichloro-2-(triphenylphosphinimino)-p-benzoquinone. Can. J. Chem. 74, 2378-2385.
  5. Pinkerton, A.A. and A. Martin. (1996) Charge densities and electrostatic potentials for energetic materials. Mater. Res. Soc. Symp. Proc. 418, 49-54.
  6. Martin, A., A.A. Pinkerton and A. Schiemann. (1996) Energetic materials: the biguanidinium nitrates. (1996) Acta Crystallogr., Sect. C: Cryst. Struct. Commun. C52, 966-970.
  7. Martin, A. and A.A. Pinkerton. (1996) Two energetic ionic materials: the biguanidinium perchlorates. Acta Crystallogr. Sect C: Cryst. Struct. Commun. C52, 1048-1052.
  8. Li, J., A.A. Pinkerton, D.C. Finnen, M. Kummer, A. Martin, F. Wiesemann and R.G. Cavell. (1996) Multifunctional ligands. Phosphinimine-substituted cyanofluoroaromatics including x-ray molecular structures of three representative ligands: 4,6-(CN)2C6F2-1,3-(N:PPh3)2, 4,6-(CN)2C6F3-1,3-(N:PPh2Me)2 and 4,6-(CN)2C6F2-1-(N:PPh3)-3-(N:PPh2Me).Formation of L complexes Rhodium(I). Inorg. Chem. 35, 5684-5692.
  9. Pinkerton, A.A., and A. Martin. Charge densities and electrostatic potentials for energetic materials. Mat. Res. Soc. Symp. Proc.418: 49-53, 1996.
  10. Martin, A., A.A. Pinkerton and A. Schiemann: Energetic materials. The biguanidinium nitrates. Acta Crystallogr. C52: 966-970, 1996.
  11. Martin, A. and A.A. Pinkerton. Two energetic ionic materials: the biguanidinium perchlorates. Acta. Crystallogr. C52: 1048-1052, 1996..
  12. Li, J., A.A. Pinkerton, D.C Finnen, m. Kummer, A. Martin, F. Wiesemann and R.G. Cavell. Multifunctional ligands. Phosphinimine-substituted cyanofluoroaromatics including x-ray molecular structures of three representative ligands 4,6-(CN)2C6F2-1,3-(N = PPh3) 2, ,4,6-(CN)2C6F2-1,3-(N = PPh3Me) 2 and 4,6-(CN)2C6F2-1-(N = PPh3)-3-( = PPh2Me) 2 Formation of Rhodium(I) complexes. Inorg. Chem. 35: 5684-5692, 1996.
  13. Dollimore, D., A. Martin and A.A. Pinkerton. A study of the thermal decomposition of biguanidinium dipherchlorate using thermogravimetry and mass spectroscopy. Thermochim. Acta 285: 109-117, 1996.
  14. Pinkerton, A.A. C. deDrian, and P. Vogel. Torturing the 7-oxabicyclo[2.2.1]heptane skeleton with an oxetane ring: structure of 4,7-dioxatricyclo[3.2.102,4]octane at 190 K. Acta Crystallogr. C62: 2927-2929.
  15. Li, J., K.V. Katti, A.A. Pinkerton, H. Nar and R.G. Cavell. Synthesis and characterization of phosphinimine-substituted trifluoro- or trichloro-p-benzoquinones and their cationic rh(I) complexes. The crystal and molecular structure of 3,5,6-trichloro-2 (triphenyphosphinimino)-p-benzo-quinone. Can. J. Chem. 74: 2378-2385, 1996.
  16. Guidi, A., V. Theurillat-Moritz, P. Vogel and A.A. Pinkerton. Enantiomerically pure Diels-Alder adducts of maleic anhydride to furfural acetals through thermodynamic control. Single crystal and molecular structure of (1S,-4R,r'S,5'S)-1-(4',5'-dimethyldioxolan-2'yl)-56-dimethylidene-7-oxabicyclo-[2,2.1]hept-2-ene. Tetrahed, Asymm 7: 3153-3162, 1996.
  17. Martin, A., A.A. Pinkerton, RD**. Gilardi and J.C. Bottaro. Energetic materials - the preparation and structural characterization of three biguanidinium dinitramides. Acta Crystallogr B53: 504-512, 1997.
  18. Pinkerton, A.A., A. Martin, A.P. Marchand, and A. Devasagayaraj. Intermolecular [2 + 2} photocyclization of ethyl 5-oxo-1a,2,5,5a,6,6ahexahydro-2,6-methano-2aH-indeno-[5,6-b]oxirene-2a-carboxylate. J. Chem. Crystallogr. 27: 701-705, 1997.
  19. Martin, A., A.A. Pinkerton, R.D. Gilardi and J. C. Bottaro. Energetic materials: the preparation and structural characterization of three biguanidinium dinitramides. Acta Crystallogr., Sect. B: Struct. Sci. B853: 50,512, 1997.
  20. Finnen, D.C. and A.A. Pinkerton. The chelating agent N,N,N',N'',N''',N''''-triethylenetraminehexacetic acid (TTHA). Acta Crystallogr., Sect. C: Cryst. Struct. Commun. C53: 1455-1457, 1997.
  21. Gano, J.E., C. Kluwe, K. Kirschbaum, A.A. Pinkerton, P. Sekheer, E Skrzypczak-Junkun, G. Subramaamaniam and D. Lenoir. (E)-2,2,5,5-tetramethyl-3,4-diphenylhex-3-ene, C22H28. Acta Crystallogr. Sect. C: Cryst. Struct. Commun., C53: 1723-1725, 1997.
  22. Pinkerton, A.A., F.P. Ahlers, H.F. Greiwing and B. Krebs. Dithiophosphinate complexes of the UO22+ ion containing a coordinated water molecule - solid sate structures and stereochemical regidity in solution. Inorg. Chim. Acta 257: 77-81, 1997.
  23. Kirschbaum, K., A. Martin and A.A. Pinkerton. Contamination in charge-coupled device area-detector data. J. Appl. Crstallogr. 30: 514-516, 1997.
  24. Pinkerton, A.A., A. Martin, A.P. Marchand and A. Devasagayaraj. Intermolecular photocyclization of ethyl5-oxo-1a,2,5,5a,6,6a-hexahydro-2,6,6a-hexahydro-2,6-methano-2aH-indenooxiene-2a-carboxylate. J. Chem. Crystallogr 27: 701-705, 1997.
  25. Mosimann, H., P. Vogel, A.A. Pinkerton and K. Kirschbaum. Highly stereoselective synthesis of perhydro-8a-(hydroxymethyl)phenathrene-1,2,4,5,7,8-hexol and derivatives. J. Org. Chem. 62: 3002-3007, 1997.

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Last Updated: 7/28/21