The molar attenuation coefficients (ε), wavelength in absorption maximum (λ) for studied compounds in acetonitrile.

Compound	ε [dm3 mol−1 cm−1], λ [nm]	Compound	ε [dm3 mol−1 cm−1], λ [nm]
1	19 200, 326	b	14 200, 256
2	22 700, 280	c	12 700, 252
3	19 800, 271	d	14 100, 262
4	22 500, 258	e	11 700, 266
a	16 300, 276	f	19 700, 340