Analysis of One-Bond Se-Se Nuclear Couplings in Diselenides and 1,2-Diselenoles on the Basis of Molecular Orbital Theory: Torsional Angular Dependence, Electron Density Influence, and Origin in ¹𝐽(Se,Se)

Scheme 1

How do the indirect nuclear spin-spin couplings originate? Mechanisms for ^𝑛𝐽_DSO, ^𝑛𝐽_PSO, ^𝑛𝐽_SD, and ^𝑛𝐽_FC terms, contributing to ^𝑛𝐽_TL.