Table 1. Key Structural Parameters and Associated Excited State Properties of Molecules 1a, 1b, 1c, and 1d^a.

	state	conformer	r/Å	B-X/Å	∠φ/°	∠τ/°	ES1	fS1	ET1	ΔES1–T1	ESOC
	GS	twisted	1.43		89.2	0.1	3.58	0.00002	3.42	0.16	0.15
	GS	planar*	1.40		0.2	0.1	4.04	0.47984	3.28	0.76	0.05
	T1	twisted	1.49		79.2	0.1	3.01	0.01419	3.00	0.01	0.08
1a	T1	planar*	1.40		0.8	0.5	3.85	0.00007	2.41	1.44	0.38
	S1	twisted	1.50		89.7	0.1	2.85	0.00001	2.84	0.01	0.00
	S1	planar*	1.49		0.5	0.0	3.11	0.15901	2.86	0.25	0.00
	GS	twisted	1.43	3.00	89.5	0.2	3.44	0.00005	3.40	0.04	0.16
	GS	bent*	1.41	3.31	49.4	37.4	4.05	0.37769	3.27	0.78	0.05
1b	T1	twisted	1.49	2.95	90.1	0.1	2.67	0.00001	2.67	0.00	0.01
	T1	bent*	1.40	3.31	0.0	37.5	3.83	0.01514	2.40	1.43	0.75
	S1	twisted*	1.49	3.00	89.7	0.2	2.65	0.00001	2.64	0.01	0.01
	S1	bent	1.40	3.32	1.2	35.5	3.25	0.00349	2.59	0.72	1.21
	GS	twisted*	1.44	2.69	89.9	0.0	3.44	0.00007	3.37	0.07	0.15
	GS	bent	1.41	3.08	0.2	31.2	3.77	0.27690	3.25	0.52	0.05
1c	T1	twisted	1.50	2.73	88.4	0.4	2.50	0.00001	2.50	0.00	0.01
	T1	bent*	1.42	2.81	50.8	10.1	3.21	0.03689	2.19	1.02	1.40
	S1	twisted*	1.50	2.75	1.2	89.9	2.47	0.00001	2.46	0.01	0.01
	GS	twisted*	1.48	2.83	81.5	0.6	3.62	0.00301	3.15	0.47	0.06
	GS	bent	1.41	3.34	3.22	41.2	3.69	0.14269	3.27	0.42	0.32
1d	T1	twisted*	1.49	2.90	88.9	5.2	2.45	0.00124	2.44	0.01	0.18
	S1	twisted*	1.49	2.91	89.5	6.9	2.37	0.00001	2.35	0.02	0.02

^aOnly the stable conformers are shown, and the lowest energy conformer for each state is marked with *. The bond distance r and angles ϕ and τ are defined in Figure 2. Energies are given in eV and the SOCME are in cm^–1.