Nuclear Magnetic Resonance Fluorine—Fluorine Coupling Constants

Rate constants determined by nuclear magnetic resonance.

Fast kinetic methods are used to measure reactions that take place in less time than required to mix the reagents manually and to measure the reaction by usual methods, like UV-visible spectrophotometry and fluorescence. The best known of them are rapid-mixing and relaxation methods, which are used for reactions with half-times in the millisecond and microsecond ranges, respectively. The picose...

Nuclear magnetic resonance spin–spin coupling constants from density functional theory: Problems and results

Our recently developed method for the calculation of indirect nuclear spin–spin coupling constants is studied in more detail. For the couplings between nuclei other than N, O, and F ~which have lone pairs! the method yields very reliable results. The results for J~Si–H! couplings are presented and their dependence on the basis set quality is analyzed. Also, J~H–H! and J~X–H! couplings ~X5C, Si,...

Nuclear magnetic resonance spin–spin coupling constants from coupled perturbed density functional theory

For the first time, a complete implementation of coupled perturbed density functional theory ~CPDFT! for the calculation of NMR spin–spin coupling constants ~SSCCs! with pure and hybrid DFT is presented. By applying this method to several hydrides, hydrocarbons, and molecules with multiple bonds, the performance of DFT for the calculation of SSCCs is analyzed in dependence of the XC functional ...

Refinement of Protein Tertiary Structure by Using Spin-Spin Coupling Constants from Nuclear Magnetic Resonance Measurements

Decomposition of nuclear magnetic resonance spin-spin coupling constants into active and passive orbital contributions.

The theory of the J-OC-PSP (decomposition of J into orbital contributions using orbital currents and partial spin polarization) method is derived to distinguish between the role of active, passive, and frozen orbitals on the nuclear magnetic resonance (NMR) spin-spin coupling mechanism. Application of J-OC-PSP to the NMR spin-spin coupling constants of ethylene, which are calculated using coupl...