Computed spin–orbit coupling constants between singlet and triplet excited states and norm of derivative couplings between triplet excited states for 6–8.

Compound	ΔEST/eV	ΔET1–T2/eV	SOCS1–T1/cm−1	SOCS1–T2/cm−1	DCT1–T2/bohr−1
6	0.25	0.02	0.44	0.23	29.1
7	0.46	0.34	0.42	0.46	1.2
8	0.13	0.06	0.45	0.56	1.0