Table 3. Selected Singlet Excited States (SES) (in eV and in Parentheses in Nm) with Oscillator Strength (f) Higher than 0.045 of Complexes 1–3 in Acetonitrile^a.

complex	SES	f	type	transition, ψo → ψv
1	3.24 (383)	0.049	MLLCTRe2-CO→phen(Re2), π–π*CO,phen(R2)	H–3 → L (58%)
			MMLCTRe1-OOC→Re2-py	H–1 → L (26%)
	3.55 (349)	0.057	MLLCTRe1-OOC→NA	H–1 → L+4 (82%)
	3.84 (323)	0.121	MLLCTCO-Re2-py→NA, π–π*NA	H–3 → L+4 (91%)
	4.53 (274)	0.083	MLLCTCO-Re2 → phen(Re2), π–π*phen(Re2)	H–4 → L+5 (49%)
			π–π*phen, d-dRe2	H–10 → L (17%)
	4.61 (269)	0.153	π–π*CO(Re2), d–dRe2	H–4 → L+9 (23%)
			π–π*phen(Re2), LLCTphen(Re2) → CO(Re2)	H–10 → L (23%)
2	3.49 (355)	0.110	MLLCTCO-Re-phen→NA	H → L+1 (90%)
	3.67 (338)	0.053	LLCTphen → NA	H–3 → L+1 (90%)
	4.53 (273)	0.131	LLCTCO → phen, d–d	H–1 → L+2 (30%)
			LLCTphen → NA	H–4 → L+1 (28%)
			π–π*phen	H–4 → L (18%)
3	3.11 (399)	0.069	MLLCTCO-Re-OOC→phen	H → L+1 (70%)
	4.43 (280)	0.048	MLLCTCO-Re-OOC→phen	H–1 → L+2 (92%)
	4.52 (274)	0.134	MLLCTCO-Re→phen	H–6 → L (51%)
			π–π*phen	H–5 → L (32%)

^aThe transition types are assigned based on the occupied and the virtual molecular orbitals ψ_o and ψ_v (shown in Figure 3 and Figure S1, respectively), defining the transition with normalized percent contributions listed in parentheses. Subscripts denote the main contributing moiety. (MMLCT = metal-to-metal-and-ligand charge transfer; MLLCT = metal-and-ligand-to-ligand charge transfer; LLCT = ligand-to-ligand charge transfer; and LMCT = ligand-to-metal charge transfer.)