Raymond J. Butcher
INORGANIC CHEMISTRY
202-806-6886(Voice)
202-806-5442 (FAX)
Physical Inorganic Chemistry, Bioinorganic Chemistry, X-Ray Crystallography
B.Sc. 1968, University of Canterbury, Christchurch, New Zealand
Ph.D. 1974, University of Canterbury, Christchurch, New Zealand
Postdoctoral, 1976-77, Georgetown University
My research interests span the broad areas of physical inorganic chemistry of transition metal complexes, the bioinorganic chemistry of selected transition metals such as copper, iron, nickel, manganese, and molybdenum, and X-ray structure determination. A summary of a number of areas in which research is currently in progress includes the following:
(1) Several new homo- and hetero-polynuclear transition metal cluster compounds have recently been synthesized and structurally characterized. These types of compounds are being actively sought as possible multi-electron transfer reagents or as catalysts for selected reactions. The magnetic and spectroscopic properties of these compounds serve as benchmarks for the improvement of current theories on exchange interactions in condensed systems.
(2) New binuclear copper(II) complexes are being synthesized which are diamagnetic at room temperature. These are being used as models for the type III site in multicopper oxidases and have been shown to mimic the magnetic, spectroscopic, and electrochemical properties of such enzymes. Since the coordination environment of the copper in the type III site is not well understood, these model studies will shed light on this important question.
(3) Iron is an important constituent in many crucial enzymes such as cytochrome C', hemerythrin, ribonucleotide reductase, and chloroperoxidase. In these, and related iron-containing enzymes, it is often found that the magnetic state of the iron atom is of fundamental importance to the efficacy of these enzymes. Consequently attention is being focused on the synthesis, magnetism, electrochemistry, and structures of magnetically interacting and "spin crossover" complexes of iron(III). We have recently synthesized an iron(III) complex in which both spin crossover and antiferromagnetic behavior has been observed. Considerable effort is being expended in this area of our research.
(4) The bioinorganic chemistry of molybdenum is currently the focus of a great deal of attention among inorganic chemists in view of the essential role of this element in the biological fixation of atmospheric nitrogen by the molybdenum-containing enzyme nitrogenase, and also in a number of important mammalian redox enzymes such as nitrate reductase, sulfite oxidase, xanthine oxidase, etc. In view of the complex nature of the chemistry of molybdenum and its multiple oxidation states, attention is being given to the synthesis and structural characterization of complexes of molybdenum (VI), (V), and (IV) with ligands of biological interest, i.e., those likely to be found in the biosystem in which molybdenum is located. New molybdenum complexes have been synthesized with sugars, amino-acids, flavins, and polyhydroxy alcohols and X-ray structure determinations have been carried out on several of these.
(5) It has been discovered in our laboratory that the nitration of selected heterocycles can be enhanced by factors of up to 107 if the heterocycle is coordinated to suitable "inert" metals such as cobalt(III) and chromium(III). Thus imidazole can be regiospecifically nitrated in the 4-position in 100% yield in 5 minutes at 0 0C when coordinated to Co(NH3 )53+, whereas only a low yield of a mixture of products is obtained when imidazole is nitrated at elevated temperatures for 24 hours. The generality of this reaction is being established for other inert metals and other heterocycles.
Representative Publications
R. J. Butcher, H. K. J. Powell, C. J. Wilkins, and S. H. Yong, "New Amino-acid Complexes of Molybdenum", J. Chem. Soc. Dalton, (1976) 356.
R. J. Butcher, B. R. Penfold, and E. Sinn, "The Crystal Structures of cis-Dioxodibromobis (triphenylphosphineoxide) molybdenum(VI), cis-Dioxodichlorobis (triphenylphosphineoxide) molybdenum(VI), and cis-Dioxobis (butane-2,3-diolato) molybdenum(VI) Bis (butane-2,3-diol): A Comparison of Coordination Spheres and the General Stereochemistry of Molybdenum(VI) Oxo Complexes", J. Chem. Soc. Dalton, (1979) 668.
R. J. Butcher, C. J. O'Connor, and E. Sinn, "Synthesis and Relation between Magnetism and Structure of a Trinuclear Copper(II) Hydroxy Complex [Cu3(OH)L3(ClO4)](ClO4) and a Hexanuclear Copper(II) Oxo Complex [Cu3OL'3(ClO4)]2, (LH = 3-(Phenylimino)-butanone-2-oxime, L'H = 1,2-Diphenyl-2-(methylimino)-ethanone-1-oxime)", Inorg. Chem., 20, (1981) 537.
G. A. Eisman, W. M. Reiff, R. J. Butcher, and E. Sinn, "Low Temperature Moessbauer Spectroscopy Study of Some Partially Solvated Tris(dialkyl dithiocarbamato)iron(III) Complexes: The Possibility of Stabilization of a Spin-Quartet Ground State", Inorg. Chem., 20, (1981) 3484.
R. J. Butcher, C. J. O'Connor, and E. Sinn, "Antiferromagnetically and Ferromagnetically Coupled Nickel(II) Dimers With and Without Interdimer Coupling: Solvent Effects in the preparation of Nickel(II) Dimers", Inorg. Chem., 20, (1981) 3486.
N. R. Brodsky, N. M. Nguyen, N. S. Rowan, C. B. Storm, R. J. Butcher, and E. Sinn, "pKa and Isomer Determinations of Cobalt(III) Imidazole and Histidine Complexes by NMR and X-ray Crystallography", Inorg. Chem., 23, (1984) 891.
R. G. Swisher, E. Sinn, R. J. Butcher and R. N. Grimes, "Organotransition-Metal Metallacarboranes: 5. Studies on (n6-Arene)iron(carborane) Complexes of Benzene and Biphenyl: Crystal Structures of (n6-C6H5-C6H5)Fe(Et2C2B4H4) and 1,2-[(n6-C6H6)Fe(Et2C2B4H3)]2-CH(CH3)CH2, a Hydrocarbon Linked Bis-ferracarborane", Organometallics, 4, (1985) 882
R. J. Butcher. G. B. Jameson and C. B. Storm, "The Crystal and Molecular Structure of Tetratolylporphine: Implications for the 15N Cp-MAS NMR Spectrum", J. Amer. Chem. Soc., 107, (1985) 2978.
R. J. Butcher, G. Diven, G. Erickson, G. M. Mockler and E. Sinn, "Copper Complexes of Binucleating N,N'-hydroxyalkyl-diamine-bis(salicylidine) Ligands Containing a Cu-O-Cu Bridge and an Exogenous Bridge", Inorg. Chem. Acta, 111, (1986) L55.
R. J. Butcher, G. Diven, G. Erickson, G. M. Mockler, and E. Sinn, "Towards a Hemocyanin Model. Effect of Interplanar Angles on Exchange Coupling in Binuclear Copper Complexes", Inorg. Chem. Acta, 123, L17 (1986).
K. A. Akinade, A. Adeyemo, R. J. Butcher and E. Sinn, "1-N-(N-2-Aminoethylmorpholine)-1-phenyl-2-oximo-propane-chloro-palladium(II) Chloride", Cryst. Spect. Res., 16, (1986) 597.
R. J. Butcher, C. Wei, A. R. M. Ali, S. H. Goh and E. Sinn, " Structure of Leuconolam, an Alkaloid Containing an Unusual Nine-Membered Ring", Acta Cryst., C42, (1986) 349.
J. T. Spencer, M. R. Pourian, R. J. Butcher , E. Sinn and R. N. Grimes, "Organotransition-Metal Metallacarboranes. 10. _-Complexation of nido-(PhCH2)2C2B4H6 at the C2B3 and C6 Rings. Synthesis and Crystal Structures of nido-2,3-[(CO)3-Cr(C6H5)CH2-2,3-C2B4H6 and (PhCH2)4C4B8H8", Organometallics, 6, (1987) 335.
R. J. Butcher, et. al., "The Structure of (I) Dimethyl-N,N'-[1,1'-p-enyl-enbis-(1-Methylethyl)] dicarbamate...", Polymer Reprints, 28, (1987) 472.
J. P. Jasinski, C. R. Desper, B. A. Zentner, R. J. Butcher and C. F. Day, "The Structure of (I) Dimethyl-N,N'[1,1'-p-phenylenebis(1-methylethyl)]dicarbamate, C16H26N2O4 and (II) Diethyl-N,N'[1,1'-p-phenylenebis(1-methylethyl)]dicarbamate, C18H28N2O4: Model Compounds for Diol Linked TMXDI Units in Polyurethane Hard Segments", Acta Cryst., C44, (1=88) 1135.
J. P. Jasinski, C. R. Desper, B. A. Zentner and R. J. Butcher, "The Structure of Dimethyl-N,N'-trans-1,4-cyclohexane-dicarbamate: A Model Compound for Diol Linked CHDI Units in Polyurethane Hard Segments", Acta Cryst., C44, (1988) 1137.
W. K. Ng, W. Chen, V. G. Kumar Das and R. J. Butcher, "Synthesis and Crystal Structure of Bis (triphenylarsineoxide)-(p-chlorophenyl) diphenyltin (IV) Tetraphenylborate", J. Organometal Chem., 361, (1989) 53.
R. J. Butcher, A. W. Addison and C. G. Wahlgren, "Structural Aspects of the Bis(2,2'-dipicolylamine)iron(II) Cation" Inorg. Chem. Acta., 158, (1989) 211.
Structural Evidence of Diorganotin(IV) Bischelates. Crytallographic Evidence of Seven-Coordinate Tin in Bis(2-carbomethoxyethyl)bis(N,N'-dimethyldithiocarbamato)tin(IV), [MeOC(O)(CH2)2]2Sn[SC(S)NMe2]2", Organometallic Chem., 365, (1989) 75.
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