Metals NMR spectroscopy

Transition metal NMR spectroscopy is not only a valuable source of structural information, but metal chemical shifts may also permit predictions of the reactivity and possibly even catalytic activity of a complex.51 The key to such analyses is frequently the observation of correlations of metal chemical shifts... 

The relatively small changes in chemical shift with pressure can be qualitatively explained in terms of changes in bulk susceptibility as most spectra in SCFs are obtained without internal lock. Large chemical shift ranges are a characteristic of metal NMR spectroscopy, and the changes observed on changing temperature, pressure or solvent are no more exaggerated in supercritical solvents than those observed with conventional solvents. 

Si spin lattice relaxation times. Direct evidence of pairing between alkali metal cations and silicate anions has recently been presented by McCormick et al. (14) using alkali metal NMR spectroscopy (14). The formation of cation-anion pairs was found to influence both the chemical shift and spin-relaxation time of the cation. Additional manifestations of ion pairing were observed in studies of the silicon spin relaxation and exchange between silicate anions (L5). This work revealed that cation-anion contacts affect the silicon T2 values, an effect also seen in Figure 1. 

A. V. McCormick, A. T. Bell, C. J. Radke, Evidence from alkali-metal NMR-spectroscopy for... 

W. von Phillipsborn (1999) Chemical Society Reviews, vol. 28, p. 95 - Probing organometallic structure and reactivity by transition metal NMR spectroscopy . 

Alkali metal NMR spectroscopy provides a good diagnostic tool for isolated alkali metal anions in solution and in solid alkalides. The chemical shifts are close to those calculated for the gaseous anions much more diamagnetic (negative) than the reference state of M (aq.). In solution, the chemical shifts of M are about —62, — 100, — 190. and -290 ppm for M=Na. K. Rb, and Cs. respectively, compared with calculated gas-phase values of —63,... 

Pregosin, P. S.Transition Metal NMR Spectroscopy 1991, Elsevier Amsterdam. 

Metal NMR spectroscopy is also beginning to gain favor as a technique for the characterization of encaged clusters. [156] For example, Zhang et al. [157] used Co spin echo NMR spectroscopy to characterize the size and location of the Co dusters in the cages of NaY zeolite. 

Group 1. Alkali Metals. NMR spectroscopy has been used to examine the preferential solvation of Li" in non-aqueous mixed solvents. Salt effects on the self-association of ethanol in water have been studied. The eoneentration dependence of " N, Na, and Cs chemical shifts in MNO3-HNO3 has... 

Rehder D (1986) Applications of transition metal NMR spectroscopy in coordination chemistry. Chimia 6 186-199. 

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