Behaviour of the NMR Relaxation Parameters at High Fields

Canet, Daniel; Robert, J. B.

doi:10.1007/978-3-642-48814-6_3

Cited by 2 publications

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“…Under extreme narrowing conditions and assuming a symmetric shielding tensor, the chemical shift anisotropy is given by eq : − italicR 1 CSA = ( 2 15 ) γ 2 italicB normalO normalΔ σ 2 τ normalC …”

Section: Theorymentioning

confidence: 99%

Field- and Temperature-Dependent ¹³C NMR Studies of the EDTA–Zn²⁺ Complex: Insight into Structure and Dynamics via Relaxation Measurements

2014

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The relaxation rates for the three different carbon types in EDTA (carbonyl, CH2 central, and CH2 lateral) were measured with and without Zn(2+) as a function of field strength and temperature. The use of different field strengths in combination with NOE measurements allowed for the contribution of each relaxation mechanism (chemical shift anisotropy; spin rotation; dipole-dipole) to the total relaxation rate for each carbon to be determined. Temperature studies allowed for determination of the activation energy (Ea) for the motions of each carbon type. The most surprising result was the observation that the τ(c) decreases significantly for the lateral carbon upon addition of Zn(2+) at neutral pH, going from 54 to 8.6 ps at 298 K. This appears to be a pH-dependent phenomenon as other reports indicate that τ(c) increases for the lateral carbon upon addition of Zn(2+) under strongly basic conditions.

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