CURRENT RESEARCH INTERESTS: Our major interests are in the application of
solid-state NMR techniques to various problems in physical, analytical,
inorganic, and materials chemistry.
RELAXATION IN PARAMAGNETIC SYSTEMS. The presence of paramagnetic species
drastically affects relaxation times in NMR measurements. We have developed a
unique sample preparation technique to separate the paramagnetic effects from
the bulk effects associated with powders. We have systematically determined
the geometric dependence of this phenomenon with synthetically prepared
isotopically labeled samples, and compared our results with theoretical
models. These measurements will form the basis for interpreting complicated
NMR spectra obtained from samples such as coals, polymers, organometallics,
and conducting systems.
POLYMERS. Solid-state NMR is an excellent technique for characterizing
polymer systems. Relaxation studies on a series of related ionomeric polymer
systems suggests the ionic cross links do indeed play a role in determining
the range of motions available to the polymer chains. In a separate area, we
have used a number of polyazine systems to examine the synthesis and physical
properties of a novel one-dimensional conducting system. Carbon-13 and
nitrogen-15 NMR results indicate the charge carrier is a delocalized entity,
with the charges residing primarily on the nitrogens. This observation is in
agreement with theory.
PUBLICATIONS
46. "Solid State 29Si NMR Determination of Crystalline Silica in Natural
Iron Oxide Pigments," G. Kowalczyk and J. E. Roberts, (1994) Analyt. Chim.
Acta, 286, 25-35.
45. "Solid State NMR Studies of Ions in Protective Coatings II: Lithium and
Cesium Ions in Polybutadiene Coatings," R. Turoscy, H. Leidheiser, and J. E.
Roberts, (1992) J. Electrochem. Soc., 139, 779-783.
44. "Structural and Compostition Studies on the Mineral of Newly Formed
Dental Enamel: A Chemical, X-ray Diffraction, and 31P and Proton Nuclear
Magnetic Resonance Study," L. C. Bonar, M. Shimizu, J. E. Roberts, R. G.
Griffin, and M. J. Glimcher, (1991) J. Bone and Mineral Res., 6, 1167-1176.
43. "13C and 15N Solid State NMR of Partially Methyl Substituted
Polyazines," B. C.-Gill, W. B. Euler, and J. E. Roberts, (1991)
Macromolecules, 24, 3074-3080.
42. "Analysis of Spectral Changes in Isotopically Substituted Porphyrins
Adsorbed on Melanin Surfaces by Solid State Carbon-13 Nuclear Magnetic
Resonance Spectroscopy," G. A. Duff, J. E. Roberts, and N. Foster, (1991)
Melanoma Research, 1, 201-209.
41. "Direct Evidence of a Bipolaron Charge Carrier in Conducting Polyazines
by 13C and 15N Solid State NMR: Detection of a Nitrenium Cation by Natural
Abundance 15N Solid State NMR," B. Chaloner-Gill, W. B. Euler, and J. E.
Roberts, (1991) J. Amer. Chem. Soc., 113, 6831-6834.
40. "Detection of Macroscopic Orientation Effects in Illinois Number 6 Coal
by Solid-State NMR Techniques," J. E. Roberts, K. M. Coleman, M. H. Alaimo,
and J. W. Larsen, (1991) Energy and Fuels, 5, 619-624.
39. "Solid State 31P NMR Studies of the Conversion of Amorphous Tricalcium
Phosphate to Apatitic Tricalcium Phosphate," J. E. Roberts, M. Heughebaert,
J.-C. Heughebaert, L. C. Bonar, M. J. Glimcher, and R. G. Griffin, (1991)
Calcif. Tissue Int., 49, 378-382.
38. "Synthesis of New Symmetrical Meso-substituted Porphyrins:
Tetra-6-Quinoline Porphyrin, Tetra-6-[N-methyl(13C)] quinoline Porphyrin
Tetraiodide Salt and Their Copper(II) Complexes," J. D. McCurry and J. E.
Roberts, (1990) Polyhedron, 20, 2527-2531.
37. "Two-Dimensional Dipolar-Chemical Shift NMR in Rotating Solids," A. C.
Kolbert, H. J. M. de Groot, M. H. Levitt, M. G. Munowitz, J. E. Roberts, G.
S. Harbison, J. Herzfeld, and R. G. Griffin, in Multinuclear Magnetic
Resonance in Liquids and Solids - Chemical Applications, P. Granger and R. K.
Harris, eds., Kluwer Academic Publishers, Netherlands, 1990, 339-354.
36. "Polymer/Metal and Polymer/Ion Interactions in Protective Coatings," H.
Leidheiser, A. Vertes, J. E. Roberts, and R. Turoscy, (1990) Hyperfine
Interactions, 57, 1955-1962.
James E. Roberts
35. "The Structure of Glyoxal Dihydrazone and Synthesis, Characterization,
and Iodine Doping of Unsubstituted Polyazine," B. C.-Gill, C. J. Cheer, J. E.
Roberts, and W. B. Euler, (1990) Macromolecules, 23, 4597-4603.
34. "Selective Observation of 1H NMR Resonances from Rotating Solids," T. G.
Neiss and J. E. Roberts, (1990) J. Mag. Reson., 89, 605-607.
33. "Solid State NMR Studies of Sodium Ions in a Polybutadiene Matrix," R.
Turoscy, H. Leidheiser, and J. E. Roberts, (1990) J. Electrochem. Soc., 137,
1785-1788.
32. "Solid-State 13C NMR Study of Oligomeric and Polymeric Azines," W. B.
Euler, and J. E. Roberts, (1989) Macromolecules, 22, 4221-4225.
31. "Nitrogen-15 Chemical Shielding Tensors of Diammineplatinum-II
Compounds --- Anisotropy of the 'Heavy-Atom' Shift," R. A. Santos, W.-J.
Chien, G. S. Harbison, J. D. McCurry, and J. E. Roberts, (1989) J. Mag.
Reson., 84, 357-360.
30. "Solid State NMR on Oligomeric and Polymeric Azines," W. B. Euler and J.
E. Roberts, (1989) Synthetic Metals, 29, E545-E549.
29. "Physiological and 15N-NMR Analysis of Molecular Nitrogen Fixation by
Methanococcus thermolithotrophicus, Methanobacterium bryantii, and
Methanospirillum hungatei," N. Belay, Sparling, B.-S. Choi, M. Roberts, J. E.
Roberts, and L. Daniels, (1988) Biochim. Biophys. Acta, 971, 233-245.
28. "Solid-State NMR Detection of Proton Exchange Between the
Bacteriorhodopsin Schiff Base and Bulk Water," G. S. Harbison, J. E. Roberts,
J. Herzfeld, and R. G. Griffin, (1988) J. Amer. Chem. Soc., 110, 7221-7223.
27. "Analysis of the Structure of Synthetic and Natural Melanins by
Solid-Phase NMR," G. A. Duff, J. E. Roberts, and N. Foster, (1988)
Biochemistry, 27, 7112-7116.
26. "Homonuclear J-Couplings and Rotationally Induced Sideband Enhancements
in NMR Spectra of Rotating Solids," D. P. Raleigh, G. S. Harbison, T. G.
Neiss, J. E. Roberts, and R. G. Griffin, (1987) Chem. Phys. Lett., 138,
285-290.
25. "Magic-Angle Sample Spinning," R. G. Griffin, W. P. Aue, R. A.
Haberkorn, G. S Harbison, J. Herzfeld, E. M. Menger, M. B. Munowitz, E. T.
Olejniczak, D. P. Raleigh, J. E. Roberts, D. J. Ruben, S. O. Smith, and S.
Vega, in Physics of NMR Spectroscopy in Biology and Medicine, C. Corso, ed.,
Soc. Italiana di Fisica, Bologna, Italy, 1988, 203-266.
24. "Solid State NMR Techniques," James E. Roberts and Robert G. Griffin, in
Phosphorus NMR in Biology, C. T. Burt, ed., CRC Press, Boca Raton, 1987,
63-83.
23. "Measurement of Heteronuclear Bond Distances in Polycrystalline Solids
by Solid-State NMR Techniques," J. E. Roberts, G. S. Harbison, M. G.
Munowitz, J. Herzfeld, and R. G. Griffin, (1987) J. Amer. Chem. Soc., 109,
4163-4169.
James E. Roberts
22. "Sideband Intensities in Two-Dimensional NMR Spectra of Rotating
Solids," J. Herzfeld, J. E. Roberts, and R. G. Griffin, (1987) J. Chem.
Phys., 86, 597-602.
21. "Chemical Exchange Effects in the NMR Spectra of Rotating Solids," A.
Schmidt, S. O. Smith, D. P. Raleigh, J. E. Roberts, R. G. Griffin, and S.
Vega (1986) J. Chem. Phys., 85, 4248-4253.
20. "Solid State 13C- and 15N-NMR Studies of Intrinsic Membrane Proteins:
Bacteriorhodopsin," S. O. Smith, G. S. Harbison, D. P. Raleigh, J. E.
Roberts, J. A. Pardoen, S. K. Das Gupta, R. A. Mathies, J. Lugtenburg, J.
Herzfeld, and R. G. Griffin, (1986) Proceedings of the Second International
Symposium on the Synthesis and Applications of Isotopically Labelled
Compounds, 239-46, Kansas City, MO, September 3-6, 1985.
19. "Solid State 13C- and 15N-NMR investigations of the Mechanism of Proton
Pumping by Bacteriorhodopsin's Retinal Chromophore," S. O. Smith, D. P.
Raleigh, G. S. Harbison, J. E. Roberts, J. A. Pardoen, S. K. Das Gupta, C.
Mulliken, R. A. Mathies, J. Lugtenburg, J. Herzfeld, and R. G. Griffin,
Proceedings of the 4th Conversation on the Discipline of Biomolecular
Stereodynamics, SUNY at Albany, Albany, New York, June, 1985, (1986) Biomol.
Stereodyn., 3, 159-72.
18. "Nitrogen Metabolism in Methanobacterium Thermoautotrophicum: A Solution
and Solid-State 15N NMR Study," Byong-Seok Choi, James E. Roberts, Jeremy N.
S. Evans, and Mary F. Roberts (1986) Biochemistry, 25, 2243-2248.
17. "Solid State 13C- and 15N-NMR Investigations of the Retinal Protonated
Schiff-Base Chromophore in Bacteriorhodopsin," G. S. Harbison, S. O. Smith,
J. E. Roberts, J. A. Pardoen, P. P. J. Mulder, C. Winkel, J. M. L. Courtin,
R. A. Mathies, J. Lugtenburg, J. Herzfeld, and R. G. Griffin, NMR in Biology
and Medicine, S. Chien and C. Ho, eds., Raven Press, New York, 1986, 33-43.
16. "Physical and Chemical Characterization of the Development and
Maturation of Bone Mineral," L. C. Bonar, M. D. Grynpas, J. E. Roberts, R. G.
Griffin, and M. J. Glimcher, (1985) Proceedings of the Second International
Conference on the Chemistry and Biology of Mineralized Tissues, 226-33.
15. "Solid State 31P Nuclear Magnetic Resonance Investigation of the Mineral
Phases of Bone," Albert H. Roufosse, Walter P. Aue, James E. Roberts, Melvin
J. Glimcher, and Robert G. Griffin (1984) Biochemistry, 23, 6115-6120.
14. "Comparative ENDOR Study of Six Blue Copper Proteins," James E. Roberts,
John F. Cline, Vanessa Lum, Hans Freeman, Harry B. Gray, Jack Peisach, Bengt
Reinhammar, and Brian M. Hoffman (1984) J. Amer. Chem. Soc., 106, 5324-5330.
13. "Two Dimensional Heteronuclear Chemical Shift Correlation Spectroscopy
in Rotating Solids," James E. Roberts, Shimon Vega, and Robert G. Griffin
(1984) J. Amer. Chem. Soc., 106, 2506-2512.
12. "Rotor Frequency Lines in Multiple Pulse/Magic Angle Sample Spinning NMR
Spectra," Edward O. Olejniczak, James E. Roberts, Shimon Vega, and Robert G.
Griffin, (1984) J. Mag. Reson., 56, 156-162.
James E. Roberts
11. "Electron-Nuclear Double Resonance of Copper Complexes of Human
Transferrin," James E. Roberts, Theodore G. Brown, Brian M. Hoffman, and
Philip Aisen, (1983) Biochim. Biophys. Acta, 747, 49-54.
10. "57Fe ENDOR of the Nitrogenase MoFe Protein," Brian M. Hoffman, Ronald
A. Venters, James E. Roberts, Mark Nelson, and W. H. Orme-Johnson, (1982) J.
Amer. Chem. Soc., 104, 4711-4712.
9. "Electron Nuclear Double Resonance Studies on Cytochrome c Peroxidase and
Cytochrome c Oxidase," James E. Roberts, Brian M. Hoffman, Chae-Hee Kang,
Maurice Swanson, and Emanual Margoliash, in Interaction Between Fe and
Proteins in Oxygen Binding and Electron Transport, Q. H. Gibson and C. Ho,
eds., Elsevier-North Holland, pp. 179-183(1982).
8. "95Mo and 1H ENDOR of the Nitrogenase MoFe Protein," Brian M. Hoffman,
James E. Roberts, and W. H. Orme-Johnson, (1982) J. Amer. Chem. Soc., 104,
860-862.
7. "17O ENDOR of Horseradish Peroxidase Compound I," James E. Roberts, Brian
M. Hoffman, Rick Rutter, and Lowell P. Hager (1981) J. Amer. Chem. Soc., 103,
7654-7656.
6. "Electron Paramagnetic and Electron Nuclear Double Resonance of the
Hydrogen Peroxide Compound of Cytochrome c Peoxidase," Brian M. Hoffman,
James E. Roberts, Chae-Hee Kang, and Emanual Margoliash, (1981) J. Biol.
Chem., 256, 6556-6564.
5. "Electron-Nuclear Double Resonance of Horseradish Peroxidase Compound I:
Detection of the Porphyrin -cation Radical," James E. Roberts, Brian M.
Hoffman, Rick Rutter, and Lowell P. Hager, (1981) J. Biol. Chem., 256,
2118-2121.
4. "Copper Electron-Nuclear Double Resonance of Cytochrome c Oxidase," Brian
M. Hoffman, James E. Roberts, Maurice Swanson, Samuel H. Speck, and Emanual
Margoliash, (1980) Proc. Natl. Acad. Sci. USA, 77, 1452-1456.
3. "Electron-Nuclear Double Resonance Spectra of Stellacyanin, a Blue Copper
Protein," James E. Roberts, Theodore G. Brown, Brian M. Hoffman, and Jack
Peisach, (1980) J. Amer. Chem. Soc., 102, 825-829.
2. "Electron-Nuclear Double Resonance of the Hydrogen Peroxide Compound of
Cytochrome c Peroxidase: Identification of the Free Radical Site with a
Methionyl Cluster," Brian M. Hoffman, James E. Roberts, Theodore G. Brown,
Chae-Hee Kang, and Emanual Margoliash, (1979) Proc. Natl. Acad. Sci. USA, 86,
6132-6136.
1. "14N Nuclear Quadrupole Resonance Spectra of Coordinated 1,2-
dipiperidinoethane," James E. Roberts, C. P. Cheng, and Theodore L. Brown,
(1978) Inorg. Chem., 17, 754-756.