Table 2. LL'CT absorption maxima, extinction coefficients and estimated excited state energies for (cat)Ni(bpy^tBu₂) (1), (ap)Ni(bpy^tBu₂) (2), and (ap^Ph)Ni(bpy^tBu₂) (3) in THF.

	λ max/nm	ε/M–1 cm–1	E LL'CT/eV	Solvatochromic shift a
1	620	3600	1.52	0.45
2	890	6200	1.12	0.16
3	970	8100	0.95	0.19

^aDetermined using the electronic solvent number. See ESI and ref. 9.