Calculated average metal–ligand bond distances (Å), angles (°), and G values (%) for the series of Fe(ii) polypyridyl complexes depicted in Chart 1^a.

	Fe–N (Å)	N–Fe–N (°)	G value (%)
[Fe(bpy)3]2+ (LS)	2.03	142.29	95.01
[Fe(bpy)3]2+ (HS)	2.23	128.57	84.16
[Fe(dmb)3]2+ (LS)	2.02	142.25	95.09
[Fe(dmb)3]2+ (HS)	2.23	128.56	84.16
[Fe(5,5′-dmb)3]2+ (LS)	2.03	142.39	94.98
[Fe(5,5′-dmb)3]2+ (HS)	2.23	128.61	84.20
[Fe(dtbbpy)3]2+ (LS)	2.02	142.41	95.20
[Fe(dtbbpy)3]2+ (HS)	2.23	128.55	84.16

^aUsing optimized structures from DFT calculations in vacuum, i.e., no solvent continuum applied.