Design, synthesis and in vitro bactericidal/fungicidal screening of some vanadyl(IV)complexes with mono- and di-substituted ONS donor triazoles

Figures & data

Scheme 1. Synthesis of mono-substituted schiff base derived triazoles (L¹)–(L³) and their vanadyl(IV) complexes (1) & (2).

Scheme 2. Synthesis of di-substituted schiff base derived triazoles (L⁴)–(L⁶) and their vanadyl(IV) complexes (3) & (4).

Table 1. Physical and analytical data of the vanadyl(IV) complexes (1)–(4).

				Calc. (Found) %
No.	Structure formula	MW in g/mole [M.P in °C]	Yield % [color]	C	H	N	V
1	[VO(L^1)2]SO4 C16H18N10O7SV	[545.32]	70	35.21	3.33	25.69	9.34
		252–254	[Dark green]	(35.17)	(3.29)	(25.64)	(9.30)
		2	[VO(L^2)2]SO4 C16H18N10S3O5V	[577.45]	68	33.28	3.14	24.24	8.82
260–262	[Green]			(33.22)	(3.11)	(24.20)	(8.78)
3	[VO(L^3)2]SO4 C28H26N10O9SV			729.51	74	46.05	3.56	19.19	6.98
		[260–262]	[Green]	(46.22)	(3.67)	(19.27)	(6.96)
		4	[VO(L^4)2]SO4 C28H26N10S5O5V	793.77	77	42.33	3.27	17.63	6.41
[273–275]	[Green]			(42.39)	(3.35)	(17.68)	(6.48)

Table 2. Physical, spectral and IR data of the vanadyl(IV) complexes.

No.	ΩM (Ω^−1cm^−1 mol^−1)	B.M (μeff)	λmax (cm^−1)	IR (cm^−1)
1	95	1.71	13 290, 18 502, 26 879, 36 104	1621 (C = N), 1086 (SO4), 978 (V = O), 868 (C–S), 495 (V–O), 422 (V–N).
2	98	1.73	13 334, 18 468, 26 846, 36 154	1620 (C = N), 1084 (SO4), 977 (V = O), 1115 (C–O), 476 (V–S), 417 (V–N)
3	92	1.74	13 275, 18 528, 26 892, 36 094	1622 (C = N), 1083 (SO4), 976 (V = O), 868 (C–S), 497 (V–O), 422 (V–N).
4	95	1.73	13 341, 18 438, 26 869, 36 142	1618 (C = N), 1082 (SO4), 980 (V = O), 1115 (C-O), 475 (V–S), 417 (V–N).

Figure 1. Proposed mass fragmentation pattern of triazole ligand (L¹).

Table 3. Bactericidal activity (concentration used 1 mg/mL of DMSO) of Triazole schiff bases and their vanadyl(IV) complexes [Zone of Inhibition (mm)].

Bacteria	Compounds [zone of Inhibition (mm)]
	(L^1)	(L^2)	(L^3)	(L^4)	(L^5)	(L^6)	(1)	(2)	(3)	(4)	(A)	SD
Gram-negative
(a)	16	13	14	18	14	16	22	19	24	19	10	29
(b)	14	12	12	16	13	17	19	18	21	17	12	30
(c)	19	15	14	19	17	18	25	24	25	24	11	30
(d)	12	14	14	14	17	18	18	20	17	20	10	29
Gram-positive
(e)	17	16	16	17	18	20	22	23	22	24	08	27
(f)	16	11	17	16	14	19	21	19	23	18	09	28
SA =	1.83	1.51	1.90	2.32	2.48	3.20	2.48	2.43	2.83	3.01	1.41	1.72

(a) = E. Coli, (b) = S. Flexneri, (c) = P. Aeruginosa, (d) = S. Typhi (e) = S. Aureus, (f) = B. Subtilis; <10 = weak; 11–15 = moderate; 16 and above = Significant; (A) = 3,5-Diamino-1,2,4-triazole; SD, standard drug = Imipenum; SA, statistical analysis.

Figure 2. Comparison of bactericidal activity of triazole schiff bases versus vanadyl(IV) complexes.

Figure 3. Comparison of fungicidal activity of triazole schiff bases versus vanadyl(IV) complexes.

Table 4. Fungicidal activity (concentration used 200 µg/mL) of triazole schiff bases and their vanadyl(IV) complexes [% inhibition].

	Compounds
Organism	(L^1)	(L^2)	(L^3)	(L^4)	(L^5)	(L^6)	(1)	(2)	(3)	(4)	SD
(a)	55	43	56	46	59	40	71	54	59	76	100
(b)	59	35	60	57	62	61	74	48	64	78	100
(c)	51	54	58	44	64	70	59	68	65	77	100
(d)	56	57	61	45	67	57	67	70	72	80	100
(e)	65	52	56	52	56	35	75	74	76	73	100
(f)	45	48	70	48	64	55	57	57	63	82	100
SA =	20.58	4.86	7.72	8.86	20.15	13.16	4.32	10.58	8.80	7.37

(a) = T. Longifusus (b) = C. Albicans (c) = A. Flavus (d) = M. Canis (e) = F. Solani (f) = C. 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 (1)–(4) against selected bacteria and in vitro cytotoxic bioassay of ligands, (L¹)–(L⁶) and vanadyl(IV) complexes (1)–(4).

	Minimum inhibitory concentration (M/mL)				Cytotoxic bioassay
No.	E. Coli	P. Aeruginosa	S. Aureus	B. Subtilis	LD50 (M/mL)
(L^1)	–	–	–	–	>7.19 × 10^−4
(L^2)	–	–	–	–	>5.81 × 10^−3
(L^3)	–	–	–	–	>6.11 × 10^−4
(L^4)	–	–	–	–	>7.19 × 10^−2
(L^5)	–	–	–	–	>5.81 × 10^−4
(L^6)	–	–	–	–	>6.11 × 10^−4
(1)	–	2.62 × 10^−7	3.54 × 10^−7	–	>6.11 × 10^−4
(2)	–	1.64 × 10^−7	1.67 × 10^−7	–	>4.14 × 10^−4
(3)	1.68 × 10^−8	4.54 × 10^−8	5.42 × 10^−7	1.98 × 10^−8	>3.69 × 10^−4
(4)	–	1.76 × 10^−8	2.16 × 10^−8	–	>4.14 × 10^−4