Extension of the Karplus Relationship for NMR Spin-Spin Coupling Constants to Nonplanar Ring Systems: Pseudorotation of Tetrahydrofuran

Extension of the Karplus Relationship for NMR Spin-Spin Coupling Constants to Nonplanar Ring Systems: Pseudorotation of Tetrahydrofuran

Karplus relationships for all 26 NMR spin-spin coupling constants (SSCCs) J of the pseudorotating tetrahydrofuran (THF) molecule were derived by expanding J as a function J(q,φ) of the puckering amplitude q and the pseudorotational phase angle φ. For this purpose, the conformational potential V(q,φ) of THF was determined at the MBPT(2)/ccpVTZ and B3LYP/6-31G(d,p) levels of theory. THF is a slig...

NMR Spin-Spin Coupling Constants in Gaussian 03 for dummies

Experimental Determination of Pseudorotation Potentials for Disubstituted Cyclopentanes Based on Spin–Spin Coupling Constants

Complete analysis of H-NMR spectra of trans-1,2-dichlorocyclopentane and trans-1,2-dibromocyclopentane was performed with use of our total lineshape fitting algorithm VALISA. The resulting high precision spin-spin coupling constants were then applied to the problem of conformational analysis, yielding a continuos potential of pseudorotation for the studied compounds in CDCl3, CCl4, and CD3CN so...

Relativistic Computation of NMR Shieldings and Spin-spin Coupling Constants

2 Relativistic theory of NMR shieldings and spin-spin coupling constants 3 2.1 Relativity in quantum chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 Nuclear shieldings and spin-spin couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3 Computational methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

Calculation and analysis of NMR spin-spin coupling constants.

The analysis of NMR spin-spin coupling leads to a unique insight into the electronic structure of closed-shell molecules, provided one is able to decode the different features of the spin-spin coupling mechanism. For this purpose, the physics of spin-spin coupling is described and the way how spin-spin coupling constants (SSCCs) can be quantum mechanically determined. Based on this insight, a s...