Direct determination of NMR correlation times from spin-lattice and spin-spin relaxation times

The NMR rotational correlation equations for dipolar relaxation between H-1 and the nuclei, 1H, C-13, P-31, and Cd-113 have been solved for viscous solutions using the R-2/R-1 dipolar ratio. The rotational correlation times have been determined over the dipolar R-2/R-1 range of 1.1-1200 at field strengths of 4.7, 6.35, 7.05, 9.4, 11.75, and 14.1 T. The calculated correlation times at each field strength have been fitted to pairs of polynomials which reproduce the correlation times from R-2/R-1 values at a given temperature. The C-13-H-1 and H-1-H-1 equations are used to determine the Al-27 nuclear quadrupole coupling constants in 1:2 LiCl-ethylaluminum dichloride melts and neat ethylaluminum dichloride. The Cd-113-H-1 and P-31-H-1 polynomials are used to characterize Cd2+ and inorganic phosphate binding sites in the enzyme, yeast inorganic pyrophosphatase.