Both BS-DFT and CASSCF/NEVPT2 calculations show a nearly linear decrease in J In BS-DFT, the projection methods of Noodleman and Ruiz represent the extreme cases of weak and strong overlap between magnetic orbitals, respectively. Due to only small amounts of spin contamination encountered in all three model complexes, the denominator term found in Yamaguchi's formula approaches the term found in the weak coupling limit described by Noodleman, resulting in similar J coupling constants for both projection schemes.