Chemical Shifts in the Nuclear Magnetic Resonance of Co59 and the Ligand Field Theory

Multinuclear Magnetic Resonance Spectroscopy of Centered Zirconium Halide Clusters

“…The large ranges over which chemical shifts vary for cobalt and manganese is understood to result from large induced paramagnetic contributions that are in turn characteristic of transition metal compounds where low-lying d manifold excited states are accessible. For example, studies of Co III (d 6 ) complexes show a clear qualitative correlation between chemical shift, temperature-independent paramagnetism (TIP), and ligand field strength. − This correlation can be seen in Table where the weak field (but still low-spin) hexaaquo complex, [Co(H 2 O) 6 ] 3+ , stands at the deshielded extreme of the known chemical shift range. Of course, the hexaaquo ion occupies a position near the high-spin to low-spin crossover point as a function of ligand field strength and therefore possesses very low-lying paramagnetic excited states.…”

“…For example, studies of Co III (d 6 ) complexes show a clear qualitative correlation between chemical shift, temperature-independent paramagnetism (TIP), and ligand field strength. [57][58][59][60][61][62][63][64] This correlation can be seen in Table 4 where the weak field (but still low-spin) hexaaquo complex, [Co(H 2 O) 6 ] 3+ , stands at the deshielded extreme of the known chemical shift range. Of course, the hexaaquo ion occupies a position near the high-spin to low-spin crossover point as a function of ligand field strength and therefore possesses very low-lying paramagnetic excited states.…”

Infrared, Raman, and hydrogen-1, carbon-13, and lead-207 nuclear magnetic resonance spectra of hexamethyldilead

“…The results for 59Co and 195Pt chemical shifts may be compared here. 32,33 We therefore conclude that 207Pb chemical shift differences between related lead compounds are not necessarily dominated by the paramagnetic term and the neighboring anisotropy effect of the (CH3)3Pb group may be more important in hexamethyldilead.…”

Cobalt-59 nuclear magnetic resonance studies on hexakis(phosphite)-cobalt(III) complexes

“…These shifts have also been associated5,6,8 with an increase in covalency which can be expressed by introducing a (/)2 term into eq 1, where k' (the orbital reduction factor12) is the coefficient of the dz2 and dx2_y2 AO's on cobalt in the ligand field treatment. Inclusion of the diamagnetic contribution of the cobalt ion12 into eq 1 gives (2), where i denotes…”