Synthesis, characterization and biological properties of thienyl derived triazole Schiff bases and their oxovanadium(IV) complexes

Figures & data

Scheme 1.  Preparation of ligands (L¹)-(L⁵) and their oxovanadium(IV) complexes (1)–(5).

Table 1.  Physical and micronalytical data of the oxovanadium(IV) complexes (1)–(5).

No.	Complex	m.p. (°C)	Yield (%)	Calc. (Found) %
				C	H	N	V
(1)	(VO(L^1)2)SO4 (549.38)	262–264	84	30.60	2.57	25.27	9.27
	C14H14N10O5S3V (light green)			30.64	2.55	25.46	9.24
(2)	(VO(L^2)2)SO4 (577.43)	261–263	81	33.25	3.12	24.25	8.82
	C16H18N10O5S3V (deep green)			33.22	3.09	24.23	8.78
(3)	(VO(L^3)2)SO4 (577.43)	258–260	72	33.25	3.12	24.25	8.82
	C16H18N10O5S3V (sea green)			33.23	3.10	24.22	8.79
(4)	(VO(L^4)2)SO4 (618.27)	244–246	78	27.17	1.94	22.64	8.24
	C14H12Cl2N10O5S3V (light green)			27.15	1.92	22.61	8.22
(5)	(VO(L^5)2)SO4 (639.37)	281–283	82	26.30	1.88	26.28	7.97
	C14H12N12O9S3V (deep green)			26.27	1.86	26.23	7.94

Table 2.  Conductivity, magnetic and spectral data of oxovanadium(IV) complexes.

No.	ΩM (Ω^−1 cm^2 mol^−1)	BM (µeff)	λmax (cm^−1)	IR (cm^−1)
(1)	82	1.75	13269, 18546, 26955, 36197	1619 (HC=N), 1088 (SO4), 976 (V=O), 865 (C-S), 419 (V-N), 375 (V-S)
(2)	84	1.74	13344, 18489, 26934, 36211	1621 (HC=N), 1082 (SO4), 978 (V=O), 867 (C-S), 415 (V-N), 371 (V-S)
(3)	83	1.73	13365, 18473, 26971, 36288	1620 (HC=N), 1085 (SO4), 980 (V=O), 872 (C-S), 416 (V-N), 375 (V-S)
(4)	86	1.72	13384, 18509, 27016, 36354	1620 (HC=N), 1086 (SO4), 984 (V=O), 870 (C-S), 427 (V-N), 380 (V-S)
(5)	89	1.77	13413, 18556, 27087, 36404	1617 (HC=N), 1083 (SO4), 987 (V=O), 874 (C-S), 434(V-N), 388 (V-S)

Table 3.  Antibacterial activity (concentration used 1 mg/mL of DMSO) of triazole Schiff bases and oxovanadium(IV) complexes.

Bacteria						Compounds (Zone of inhibition (mm))
	(L^1)	(L^2)	(L^3)	(L^4)	(L^5)	(1)	(2)	(3)	(4)	(5)	SD
Gram-negative
(a)	16	13	16	17	19	19	16	18	24	26	29
(b)	17	14	18	15	18	21	18	21	19	25	31
(c)	14	17	14	17	19	18	19	17	20	24	30
(d)	16	12	15	17	21	20	16	19	23	26	29
Gram-positive
(e)	12	16	08	16	17	17	20	17	21	22	26
(f)	17	14	13	14	18	19	17	16	19	24	28
SA	1.83	1.97	3.41	1.26	1.37	1.41	1.63	1.79	2.10	1.52	1.72

(a), Escherichia coli; (b), Shigella flexneri; (c), Pseudomonas aeruginosa; (d), Salmonella enterica serover typhi; (e), Staphylococcus aureus; (i), Bacillus subtilis; 10< weak; >10 moderate; >16 and above significant; SD, standard drug (imipenem) SA, statistical analysis.

Table 4.  Antifungal activity (concentration used 200 µg/mL) of triazole Schiff bases and oxovanadium(IV) complexes.

Organism						Compounds
	(L^1)	(L^2)	(L^3)	(L^4)	(L^5)	(1)	(2)	(3)	(4)	(5)	SD
(a)	45	50	44	55	48	61	63	58	69	63	A
(b)	24	57	56	00	55	48	72	70	38	72	B
(c)	52	48	00	44	60	63	59	35	56	78	C
(d)	43	38	41	46	58	55	58	56	60	75	D
(e)	55	43	50	38	45	67	56	42	55	61	E
(f)	00	54	47	29	44	42	68	63	64	70	F
SA	20.91	7.00	20.11	19.56	6.89	9.55	6.25	13.13	5.65	6.66

(a), Trichophyton longifucus; (b), Candida albican; (c), Aspergillus flavus; (d), Microscopum canis; (e), Fusarium solani; (f), Candida glabrata; SD, standard drugs MIC µg/mL; A, miconazole (70 µg/mL: 1.6822 × 10⁻⁷ M/mL); B, miconazole (110.8 µg/mL: 2.6626 × 10⁻⁷ M/mL); C, amphotericin B (20 µg/mL: 2.1642 × 10⁻⁸ M/mL); D, miconazole (98.4 µg/mL: 2.3647 × 10⁻⁷ M/mL); E, miconazole (73.25 µg/mL: 1.7603 × 10⁻⁷ M/mL); F, miconazole (110.8 µg/mL: 2.66266 × 10⁻⁷ M/mL). SA, statistical analysis.

Table 5.  Minimum inhibitory concentration (M/mL) of the selected compounds (4) and (5) against selected bacteria.

Microorganisms	MIC (M/mL)^a (4) (5)
Escherichia coli	2.323 × 10^−6	2.324 × 10^−6
Shigella flexneri	ND	ND
Pseudomonas aeruginosa	ND	ND
Salmonella enterica serover typhi	2.342 × 10^−6	3.212 × 10^−7
Staphylococcus aureus	3.179 × 10^−5	2.127 × 10^−7
Bacillus subtilis	1.672 × 10^−7	3.891 × 10^−8

^aEach compound was measured three times, with a standard deviation (SD) less than 10% in all the cases. ND is not determined at tested concentrations.