NMR magnetic susceptibility

The first tris(pentamethylcyclopentadienyl) complex of uranium was synthesized in 50% yield by hydrogenation of tetramethylfulvene with Cp 2UH(dmpe) (Scheme 34) and characterized by common analytical methods (IR, H, 13C NMR, magnetic susceptibility and elemental analysis).89,89a... 

Other magnetic measurements of catalysts include electron paramagnetic resonance and magnetic susceptibility. Although those are not as common as NMR, they can be used to look at the properties of paramagnetic and ferromagnetic samples. Examples of these applications can be found in the literature [87. 

Magnetic-susceptibility measurements showed the presence of UF4 in heated samples. Ebert et al. (E14) reported a nominal stoichiometry CisUFg, magnetic-susceptibility measurements indicating partial reduction at room temperature, with 10% of the uranium species present as U(IV). Wide-line NMR demonstrated the presence of both U(VI) and U(IV). 

The significant improvements in sensitivity achieved during the last 5 years have been because of improved probe design and radiofrequency circuits. Since the probe needs to be located very close to the sample, it must be made of a material with a low magnetic susceptibility, for otherwise it would cause distortions of the static magnetic field thereby adversely affecting line shape and resolution. Much research has therefore been undertaken by NMR spectrometer manufacturers to develop materials that... 

Spin-state transitions have been studied by the application of numerous physical techniques such as the measurement of magnetic susceptibility, optical and vibrational spectroscopy, the Fe-Mbssbauer effect, EPR, NMR, and EXAFS spectroscopy, the measurement of heat capacity, and others. Most of these studies have been adequately reviewed. The somewhat older surveys [3, 19] cover the complete field of spin-state transitions. Several more recent review articles [20, 21, 22, 23, 24, 25] have been devoted exclusively to spin-state transitions in compounds of iron(II). Two reviews [26, 27] have considered inter alia the available theoretical models of spin-state transitions. Of particular interest is the determination of the X-ray crystal structures of spin transition compounds at two or more temperatures thus approaching the structures of the pure HS and LS electronic isomers. A recent survey [6] concentrates particularly on these studies. 

It is thus evident that, in order to interpret the results obtained by one of the relaxation methods, a thorough investigation of the unperturbed equilibrium properties is required. In general, solution magnetic susceptibilities measured by the NMR method of Evans [83, 84] are used to this end, the equilibrium constant for the equilibrium in Eq. (37) being determined by ... 

The electrocrystallization and characterization of a novel molecular metal which displays both electronic and ionic conduction has been reported. The complex Li0.6(15-crown-5-ether)[Ni-(dmit)2] H20 is composed of stacks of [Ni(dmit)2] units which provide pathways for electronic conduction. The stacks are separated by parallel stacks of 15-crown-5-ether moieties in a channellike formation which facilitates ion conduction. The salt has a room temperature conductivity of 240 Scm-1. Temperature-dependent magnetic susceptibility and NMR measurements were used to prove the existence of Li+ movement within the crown ether channels.1030... 

W. Kutzelnigg, U. Fleischer, M. Schindler, The IGLO-method Ab initio Calculation and Interpretation of NMR Chemical Shifts and Magnetic Susceptibilities, in NMR Basic Principles and Progress, Vol. 23, p. 165 ff., Springer, Berlin 1990. 

Ishikawa etal. proposed an approach for the determination of the ligand-field (LF) parameters of a set of isostructural lanthanide complexes. This method consists of a simultaneous fit of the temperature dependence of magnetic susceptibilities and NMR spectra for the whole isostructural series [18]. In order to avoid over-parametrization a key restriction is imposed each parameter is expressed as a linear function of the number of f electrons, n ... 

Solutions of alkali metals in liquid ammonia have been studied by many techniques. These include electrical conductivity, magnetic susceptibility, nuclear magnetic resonance (NMR), volume expansion, spectroscopy (visible and infrared), and other techniques. The data obtained indicate that the metals dissolve with ionization and that the metal ion and electron are solvated. Several simultaneous equilibria have been postulated to explain the unique properties of the solutions. These are generally represented as follows ... 

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