The increased blood oxygenation level-dependent contrast-to-noise ratio at ultrahigh field (7 T) has been exploited in a comparison of the spatial location and strength of activation in high-resolution (1.5 mm isotropic) gradient echo (GE) and spin echo (SE), echo planar imaging data acquired during the execution of a simple motor task in five subjects. SE… (More)
A continuous wave and pulse electron paramagnetic resonance study of the base-on form of cob(II)alamin diluted in hydroxocob(III)alamin powder is presented. HYSCORE spectroscopy at X-and Q-band was used to study the weakly coupled corrin nitrogens and the remote nitrogen of the axial dimethylbenzimidazole ligand. Simulations of the spectra measured at… (More)
Double electron-electron resonance (DEER) spectroscopy can determine, from measurement of the dipolar interaction, the distance and orientation between two paramagnetic centres in systems lacking long-range order such as powders or frozen solution samples. In spin systems with considerable anisotropy, the microwave pulses excite only a fraction of the… (More)
The structural, chemical and electronic changes of ceria as a function of decreasing particle size have been studied: at sizes below 5 nm the total amount of reducible oxygen dramatically increases due to superoxide formation on the ceria surface, a result indicative of a size dependent oxygen buffering capacity.
Metal-stabilized phenoxyl radicals appear to be important intermediates in a variety of enzymatic oxidations. We report that transition metal coordination also supports an aminyl radical, resulting in a stable crystalline complex: [Rh(I)(trop2N.)(bipy)]+OTf- (where trop is 5-H-dibenzo[a,d]cycloheptene-5-yl, bipy is 2,2'-bipyridyl, OTf- is… (More)
In this contribution we present a continuous wave (CW), pulse electron paramagnetic resonance (EPR), and pulse electron nuclear double resonance (ENDOR) study of (OEC)Co(C 6 H 5), where OEC is the trianion of To facilitate spectral assignments isotopic substitutions were employed (2 H and 13 C). From the analysis of the frozen solution CW EPR, ESEEM, and… (More)
Cyclopropane and its derivatives (ER 2) 3 (E = C, Si, Ge, Sn), bicyclobu-tanes, and other strained hydrocarbons have remarkably low oxidation potentials when compared to their unstrained linear counterparts. [1–3] Can this property be translated to transition-metal complexes, such that small rings incorporating the transition metal lead to more facile… (More)
In memoriam Professor Hanns Fischer This review discusses the application of pulse EPR to the characterization of disordered systems, with an emphasis on samples containing transition metals. Electron nuclear double-resonance (ENDOR), electron-spin-echo envelope-modulation (ESEEM), and double electron–electron resonance (DEER) methodologies are outlined.… (More)