| AUTHOR |
TITLE |
Zhang, D.,
Busch, D. H.,
Lennon, P. L.,
Weiss, R. H.,
Neumann, W. L.,
Riley, D. P. |
Iron(III) Complexes as Superoxide Dismutase Mimics: Synthesis, Characterization, Crystal Structure, and Superoxide Dismutase (SOD) Activity of Iron(III) Complexes Containing Pentaaza Macrocyclic Ligands
Inorganic Chemistry; 1998; 37(5); 956-963. (Article) |
Experimental Section
Instrumentation.
The rate constant for the catalyzed superoxide dismutation reaction of superoxide was measured by the stopped-flow spectrophotometric methods reported previously and by utilizing an OLIS rapid-scan spectrophotometer/stopped-flow system. In general, the FeIII(L) complexes were dissolved in 80 mM HEPES buffer solutions, and the saturated KO2 solution (~0.2 M) in DMSO was freshly prepared. On the instrument, an aqueous solution of the complex and DMSO solution of KO2 (mixing ratio: 19/1 water to DMSO) were injected into the mixing cell from two syringes, and the decay of absorbance of superoxide (λmax = 245 nm) was monitored. The background decay of superoxide itself is second-order and at the pH range utilized in these studies (7.4-8.1) is much slower than the catalytic rates measured with these catalysts when they are utilized at the 10-6 M concentration range. |
Johnson, M. D.,
Read, J. F. |
Kinetics and Mechanism of the Ferrate Oxidation of Thiosulfate and Other Sulfur-Containing Species
Inorganic Chemistry; 1996; 35(23); 6795-6799. (Article) |
Experimental Section
Kinetic Measurements. The reaction rates were measured spectrophotometrically using a D110 Durrum spectrophotometer with an OLIS computer interface. The reactions were monitored at 505 nm under pseudo-first-order conditions with the reductant in at least 10-fold excess. Typical reductant ranges were between 0.05 and 0.002 M. Absorbance changes were fitted using an OLIS data fitting routine. Each rate constant is an average of three to five trials. The temperature was controlled to within 0.1 °C. For determination of the activation parameters, five to seven temperatures ranging from 12 to 34.0 °C were used. All studies were conducted using 0.05 M phosphate buffers (I = 1.0 M NaClO4) to control pH and to prevent any precipitation of iron hydroxide/oxides by complexation of the iron final product. No effect on the observed rate constants was found between the phosphate concentrations of 0.01 and 0.05 M. The ferrate concentrations were between 1 × 10-4 and 5 × 10-4 M. |
Karki, L.,
Williams, R. D.,
Hupp, J. T.,
Allan, C. B. |
Electroabsorption and Related Spectroscopic Studies of Bimetallic Tetraiminoethylenedimacrocyclic Complexes: Corroboration of Valence Electron Delocalization
Inorganic Chemistry; 1998; 37(11); 2837-2840. (Note) |
Experimental Section
[Ru2TIEDCl4](PF6), Fe2TIEDCl4, and [Fe2TIEDCl4](PF6) were synthesized and characterized according to literature methods. Absorption and electroabsorption studies were performed on a 5:1 (v:v) 2-methyltetrahydrofuran/acetonitrile mixture at 77 K. The sample was dissolved in a deoxygenated solvent matrix, then loaded rapidly into the Stark cell, and immersed in liquid nitrogen. The electroabsorption procedure used here was similar to the method described in detail elsewhere. Briefly, however, measurements were performed with an Olis modified Cary-14 spectrophotometer in single-beam mode. A large, oscillating electric field (~107 V/m) was applied across the sample, and the field dependent and independent transmittance signals were detected with a Hamamatsu silicon photodiode (S 5591). |
Karki, L.,
Hupp, J. T. |
Electroabsorption Studies of Metal-to-Ligand Charge Transfer in Ru(phenanthroline)32+: Evidence for Intrinsic Charge Localization in the Initially Formed Excited State
Inorganic Chemistry; 1997; 36(15); 3318-3321. (Article) |
Experimental Section
The hexafluorophosphate salt of ruthenium(II) tris(phenanthroline) was synthesized and purified according to a literature method. Absorption measurements were performed at 77 K in a 1:1 (v:v) butyronitrile:2-methyl tetrahydrofuran glass by using a retrofitted Cary-14 spectrophotometer featuring OLIS control software. |
Nielson, R. M.,
Lyon, L. A.,
Hupp, J. T. |
Primitive Molecular Recognition Effects in Electron Transfer Processes: Modulation of ((Trimethylammonio)methyl)ferrocenium/ferrocene Self-Exchange Kinetics via Hydrophobic Encapsulation
Inorganic Chemistry; 1996; 35(4); 970-973. (Article) |
Experimental Section
Measurements.
Near-infrared absorption measurements were made in D2O with an OLIS-modified Cary 14 spectrophotometer |
Dai, S.,
Shin, Y. S.,
Toth, L. M.,
Barnes, C. E. |
Comparative UV-Vis Studies of Uranyl Chloride Complex in Two Basic Ambient-Temperature Melt Systems: The Observation of Spectral and Thermodynamic Variations Induced via Hydrogen Bonding
Inorganic Chemistry; 1997; 36(21); 4900-4902. |
| UV-visible spectra were measured at room temperature with a Cary 14H scanning spectrophotometer interfaced to a PC for data collection and analysis via On-Line Instrument Systems (OLIS) software and hardware. Samples were loaded into a quartz cuvette (1 cm path length) with a threaded glass cap. |
Dai, S.,
Metcalf, D. H.,
Del Cul, G. D.,
Toth, L. M. |
Spectroscopic Investigation of the Photochemistry of Uranyl-Doped Sol-Gel Glasses Immersed in Ethanol
Inorganic Chemistry; 1996; 35(26); 7786-7790. (Article) |
Experimental Section
Photochemical Experiment.
Visible and near-IR spectra were measured by a Cary 14 scanning spectrophotometer. Spectral data were collected and stored by On-Line Instrument Systems (OLIS) for data acquisition interface. Sol-gel glass samples were immersed in the ethanol contained in a quartz cuvette (0.5 cm pathlength). The ethanol is in contact with the atmosphere. UV-visible spectra were taken in-situ during the photolysis of the sample by 457 nm line of an argon ion laser (Spectra-Physics Model 165, about 70 mW laser power on samples) |
Higgs, T. C.,
Ji, D.,
Czernuszewicz, R. S.
Matzanke, B. F.
Schunemann, V.,>br >Trautwein, A. X.,
Helliwell, M.,
Ramirez, W.,
Carrano, C. J. |
The Fe(III), Co(III), and V(III) Complexes of the "Heteroscorpionate" Ligand (2-Thiophenyl)bis(pyrazolyl)methane
Inorganic Chemistry; 1998; 37(10); 2383-2392. (Article) |
Experimental Procedures
Solution electronic spectra were obtained on a Hewlett-Packard 8452A diode array spectrophotometer under the computer control of a PC with OLIS diode array spectrophotometry software (On-Line Instruments, Inc.). |
Higgs, T. C.,
Spartalian, K.,
O'Connor, C. J.,
Matzanke, B. F.,
Carrano, C. J. |
Synthesis and Characterization of a Series of Edge-Sharing Octahedral-Tetrahedral-Octahedral Linear Trinuclear Complexes [M3(L1O)4]2+, Where M = Mn2+, Co2+, Ni2+, Cu2+, and Zn2+ and L1OH Is the "Heteroscorpionate" Ligand (2-Hydroxyphenyl)bis(pyrazolyl)met
Inorganic Chemistry; 1998; 37(9); 2263-2272. (Article) |
Experimental Section
Microanalyses were performed by Desert Analytics Laboratory, Tucson, AZ. IR spectra were recorded as KBr disks on a Perkin-Elmer 1600 Series FTIR. Solution electronic spectra were obtained using a Hewlett-Packard 8452A diode array spectrophotometer under the computer control of a Compaq Deskpro 386S with OLIS diode array spectrophotometry software (On-line Instruments Inc.). |
Higgs, T. C.,
Dean, N. S.,
Carrano, C. J. |
Homo- and Heterometallic Mono-, Di-, and Trinuclear Co2+, Ni2+, Cu2+, and Zn2+ Complexes of the "Heteroscorpionate" Ligand (2-Hydroxyphenyl)bis(pyrazolyl)methane and Its Derivatives
Inorganic Chemistry; 1998; 37(7); 1473-1482. (Article) |
Experimental Section
Solution electronic spectra were obtained using a Hewlett-Packard 8452A diode array spectrophotometer under the computer control of a Compaq Deskpro 386S with OLIS model 4300 data system diode array spectrophotometry software (On-line Instruments Inc.). |
