Table 4.

Structural parameters and Heisenberg coupling constants for 3.

Bond length [Å]/ Angle [°][a]	Vacuum BS-B3LYP// OLYP[b]	COSMO BS- B3LYP//OLYP[b]	Experimental[c]
Fe–Fe	2.75	2.76	2.70
Fe–N1	1.65	1.64	1.66
Fe–N2	1.64	1.65	1.66
N1–O1	1.21	1.20	1.16
N2–O2	1.21	1.21	1.16
Fe–S	2.25	2.25	2.24
Fe1-N1-O1	160.0	160.8	165.9
Fe2-N2-O2	163.7	163.6	165.9

J[d][cm−1]	Vacuum	COSMO
Noodleman[e]	7462	8773
Yamaguchi[f]	3476	4322

^[a]See Figure 7 A for atom numbering.

^[b]Broken-symmetry electronic structure optimized with B3LYP (Gaussian/6-311G(d,p)) at OLYP geometry (ADF/TZP).

^[c]Ref. [52]. Reported values are averages.

^[d]Based on $\mathscr{H}=J{S}_{\mathrm{A}}{S}_{\mathrm{B}}$.

^[e]Equation (2).

^[f]Equation (3).