Hetarylazopyrazolone Dyes Based on Benzothiazole and Benzimidazole Ring Systems: Synthesis, Spectroscopic Investigation, and Computational Study

Table 1

Characterization data and elemental analysis of dyes 3a–3f.

Dye	Molecular formula		Cryst.		Melting point	C%		H%		N%		S%
number	(mol.wt.)		solvent	(%)	(°C)	Calc.	Found	Calc.	Found	Calc.	Found	Calc.	Found
3a	C18H12N6OS2 (392.5)	Orange	Acetic acid	87	255–257	55.09	44.90	3.08	3.11	21.41	20.94	16.34	16.09
3b	C18H11ClN6OS2 (426.9)	Orange	Acetic acid	95	265–267	50.64	50.27	2.60	2.77	19.69	19.92	15.02	14.97
3c	C19H14N6O2S2 (422.5)	Dark red		56	248–250	54.01	53.96	3.34	3.34	19.89	19.53	15.18	15.03
3d	C20H16N6OS2 (420.5)	Orange	Ethanol	94	270-271	57.12	56.73	3.84	3.56	19.99	19.42	15.25	14.82
3e	C18H13N7OS (375.4)	Orange	Acetic acid/water	76	294-295	57.59	57.20	3.49	3.52	26.12	25.88	8.54	8.11
3f	C20H17N7OS (403.5)	Orange	DMF/water	81	303-304	59.54	58.93	4.25	4.33	24.3	23.77	7.95	7.64

.
of crude product.
with ethanol.