What factors influence the metal-proton spin-spin coupling constants in mercury- and cadmium-substutited rubredoxin?

The indirect metal-proton spin-spin coupling constants between protons in cysteine groups and the mercury or cadmium nucleus have been calculated for a small model of Me-rubredoxin complex (Me = Cd, Hg) by means of density functional theory with zeroth-order regular approximation Hamiltonian (DFT-ZORA). The calculated spin-spin coupling constants, in spite of the moderate size of the model system, are in good agreement with the values measured in NMR experiment, which are in the 0.29-0.

Spin-spin coupling constants in [corrected] artificial DNA intercalated with silver cations: theoretical prediction.

The indirect nuclear spin-spin coupling constants of Ag(+) cation intercalated between imidazole rings in DNA chains are calculated by means of DFT with relativistic effects taken into account by the use of the zeroth-order regular approximation Hamiltonian (DFT-ZORA). The calculations model how the (1)J((15)N,(109)Ag) coupling constant is affected by different types of geometry deformations and by the presence of water, which is simulated by means of the polarizable continuum model and explicitly present water molecules. Calculations for systems containing two and three imidazole pairs are also carried out to model the influence of stacking interactions.

Theoretical prediction of the spin-spin coupling constants between an axis and macrocycle of a rotaxane.

The indirect nuclear spin-spin coupling constants between nuclei belonging to the axis and to the macrocycle of three structurally related rotaxanes have been calculated by means of density functional theory. It has been shown that the through-space axis-macrocycle proton-proton coupling constants can be as large as 0.4-0.