In vitro antibacterial, antifungal & cytotoxic activity of some isonicotinoylhydrazide Schiff's bases and their cobalt (II), copper (II), nickel (II) and zinc (II) complexes

Figures & data

Figure 1 Proposed structures of the ligands.

Table I.  Physical and analytical data of the metal (II) complexes (1–24).

No	Metal complex/Mol. formula	D.P (°C)	B.M (μeff)	C, H, N; Calc. (Found) %	λmax (cm^− 1)	IR (cm^− 1)
1	[Co(L^1)2Cl2][557.8] C22H16CoCl2N6O4	318–320	4.6	47.3 2.9 15.1 (47.8)(2.9)(15.2)	8615,17520, 30115	1565 (C = N), 1515 (NNH), 460 (M–O), 395, (MN), 315 (M–Cl)
2	[Co(L^2)2Cl2][585.8] C24H20CoCl2N6O4	322–324	4.8	49.2 3.4 14.3 (49.3)(3.2)(14.4)	8895,17665, 29980	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
3	[Co(L^3)2Cl2][647.8] C22H14CoCl2N8O8	335–337	4.6	40.8 2.2 17.3 (41.2)(2.3)(17.0)	8790,17570, 29995	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
4	[Co(L^4)2Cl2][711.9] C22H14CoCl2N8O6S2	320–322	4.7	37.1 2.0 15.7 (37.5)(2.3)(15.3)	8815,17595, 30105	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
5	[Co(L^5)2Cl2][619.9] C24H22CoCl2N6O2S2	326–328	4.7	46.5 3.5 13.6 (46.6)(3.8)(13.3)	8675,17615, 30000	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
6	[Co(L^6)2Cl2][589.9] C22H16CoCl2N6O2S2	316–318	4.8	44.8 2.7 14.2 (44.6)(2.9)(14.3)	8855,17630, 30111	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
7	[Cu(L^1)2]Cl2 [562.4] C22H16CuCl2N6O4	322–324	1.4	46.9 2.8 14.9 (46.6)(2.5)(15.3)	15215,19260, 30310	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N)
8	[Cu(L^2)2]Cl2 [590.4] C24H20CuCl2N6O4	322–324	1.6	48.8 3.4 14.2 (48.6)(3.0)(14.5)	15355,19675, 30175	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N)
9	[Cu(L^3)2]Cl2 [652.4] C22H14CuCl2N8O8	318–320	1.3	40.5 2.3 17.2 (40.7)(2.5)(17.4)	15265, 19285, 30355	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N)
10	[Cu(L^4)2]Cl2 [716.5] C22H14CuCl2N8O6S2	324–326	1.5	36.8 2.0 15.6 (36.3)(2.5)(15.4)	15280, 19445, 30200	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N)
11	[Cu(L^5)2]Cl2 [624.5] C24H22CuCl2N6O2S2	328–330	1.5	46.1 3.5 13.4 (46.5)(3.8)(13.5)	15310, 19550, 30285	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
12	[Cu(L^6)2]Cl2 [594.5] C22H16CuCl2N6O2S2	320–324	1.3	44.4 2.7 14.1 (44.1)(2.5)(14.3)	15345, 19615, 30245	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N)
13	[Ni(L^1)2Cl2][557.6] C22H16NiCl2N6O4	330–332	3.4	47.3 2.9 19.0 (47.6)(2.7)(19.4)	10585, 16345, 29480	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
14	[Ni(L^2)2Cl2][585.6] C24H20NiCl2N6O4	325–327	3.6	49.2 3.4 14.3 (49.5)(3.2)(14.7)	10150, 16455, 29965	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
15	[Ni(L^3)2Cl2][647.6] C22H14NiCl2N8O8	328–330	3.5	40.8 2.2 17.3 (40.5)(2.0)(17.1)	10275, 16370, 29565	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
16	[Ni(L^4)2Cl2][711.7] C22H14NiCl2N8O6S2	323–325	3.4	37.1 2.0 15.7 (37.2)(2.5)(15.3)	10465, 16395, 29615	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
17	[Ni(L^5)2Cl2][619.7] C24H22NiCl2N6O2S2	326–328	3.6	46.5 3.6 13.6 (46.2)(3.2)(13.7)	10525, 16410, 29595	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
18	[Ni(L^6)2Cl2][589.7] C22H16NiCl2N6O2S2	325–328	3.4	44.8 2.7 14.2 (45.1)(2.5)(12.4)	10440, 16435, 29815	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
19	[Zn(L^1)2Cl2][564.3] C22H16ZnCl2N6O4	328–330	Dia	46.8 2.8 14.9 (46.3)(2.5)(14.7)	28540	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
20	[Zn(L^2)2Cl2][592.3] C24H20ZnCl2N6O4	320–322	Dia	48.6 3.4 14.2 (48.9)(3.0)(14.4)	29385	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
21	[Zn(L^3)2Cl2][654.3] C22H14ZnCl2N8O8	318–320	Dia	40.4 2.1 17.1 (40.9)(2.5)(17.4)	28770	1565 (C = N), 1515 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
22	[Zn(L^4)2]Cl2][718.4] C22H14ZnCl2N8O6S2	324–326	Dia	36.8 1.9 15.6 (36.4)(2.2)(15.4)	29210	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
23	[Zn(L^5)2]Cl2][626.4] C24H22ZnCl2N6O2S2	322–324	Dia	46.0 3.5 13.4 (46.4)(3.8)(13.8)	29195	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)
24	[Zn(L^6)2]Cl2][596.4] C22H16ZnCl2N6 O2S2	325–327	Dia	44.3 2.7 14.1 (44.5)(2.9)(14.3)	28905	1565 (C = N), 1510 (NNH), 460 (M–O), 395 (M–N), 315 (M–Cl)

Figure 2 Proposed structures of the metal (II) complexes.

Table II.  In-vitro antibacterial activity data for the ligands (L¹–L⁶) and metal (II) complexes (1–24).

	Diameter of zones showing complete inhibition of growth (mm)
Compound	(a)	(b)	(c)	(d)	(e)	(f)	(g)	(h)	(j)	(k)
L^1	23	15	14	16	7	15	6	5	14	12
L^2	22	18	12	17	5	18	8	10	12	13
L^3	24	18	16	18	6	15	12	13	14	15
L^4	25	15	18	19	5	18	15	14	15	17
L^5	21	12	12	15	6	14	6	10	12	12
L^6	22	14	10	15	5	14	6	10	11	15
1	28	22	21	20	10	22	18	15	18	19
2	30	20	20	22	9	21	16	16	17	20
3	28	22	21	20	8	21	19	17	20	20
4	27	20	19	20	9	22	15	15	21	19
5	28	21	21	20	7	20	18	14	18	20
6	28	22	21	20	6	20	15	15	20	20
7	29	20	22	24	10	22	16	14	18	21
8	30	25	20	22	11	22	18	18	19	21
9	32	23	20	23	9	20	16	15	20	20
10	30	22	20	24	10	21	18	15	18	20
11	28	22	22	22	11	23	15	16	18	19
12	29	20	20	22	11	20	14	15	18	19
13	23	20	22	25	7	22	15	15	18	19
14	22	22	22	23	8	22	18	16	19	18
15	25	23	22	24	8	22	15	15	18	18
16	24	22	20	23	8	21	15	14	18	19
17	22	20	22	22	8	21	18	12	18	18
18	25	22	20	22	7	21	19	15	18	18
19	29	20	22	22	9	21	18	14	20	20
20	30	22	21	22	10	22	16	15	17	19
21	30	22	19	22	11	20	15	15	18	20
22	32	20	19	22	10	23	15	14	17	20
23	31	21	20	22	9	23	16	12	18	19
24	31	24	20	22	10	23	14	14	20	19
Imipenum	30	30	25	30	32	30	30	25	30	32

Ligand: >15 mm = significant activity; 7–14 mm = moderate activity; < 7 mm = weak activity. (a) = M. tuberculosis (b) = E. coli, (c) = K. pneumoniae, (d) = P. mirabilis, (e) = P. aeruginosa, (f) = S. typhi, (g) = S. dysenteriae, (h) = B. cereus, (j) = C. diphtheriae, (k) = S. pyogenes, (m) = S. aureus. Imipenum = standard drug.

Table III.  In-vitro antifungal activity data for the ligands (L¹–L⁶) and metal (II) complexes (1–24).

	Diameter of zones showing complete inhibition of growth (mm)
Compound	(a)	(b)	(c)	(d)	(e)	(f)
L^1	15	17	11	16	12	10
L^2	14	12	14	14	15	13
L^3	15	15	12	15	10	14
L^4	14	15	11	15	10	14
L^5	15	14	11	14	12	14
L^6	16	15	11	15	12	12
1	17	15	15	18	22	17
2	17	12	15	18	20	19
3	19	24	15	20	18	18
4	17	12	14	20	20	19
5	20	11	15	18	06	20
6	20	18	14	20	20	18
7	20	18	16	21	18	19
8	17	16	16	18	18	19
9	19	15	18	20	15	18
10	18	16	15	18	20	15
11	20	15	15	20	18	19
12	17	14	18	20	18	19
13	19	16	14	21	20	17
14	20	17	18	18	18	17
15	19	18	16	20	18	17
16	17	18	16	18	20	16
17	17	18	18	18	21	18
18	18	14	15	20	22	20
19	19	13	16	20	18	18
20	20	15	16	20	20	17
21	19	11	20	15	21	18
22	17	16	18	20	22	20
23	19	14	20	18	18	19
24	17	11	16	20	18	19
Miconazole	25	20	25	25	25	25
Amphotericin B	30	25	30	25	25	30

Ligand: >14 mm = significant activity; 7–13 mm = moderate activity; < 7 mm = weak activity. (a) = T. longifusus, (b) = C. albicans, (c) = A. flavus, (d) = M. canis, (e) = F. solani, (f) = C. glabrata. Miconazole and Amphotericin B = standard drugs.

Table IV.  Brine shrimp bioassay data for the ligands (L¹–L⁶) and their metal (II) complexes (1–24).

Compound	LD50 (μg/ml)
L^1	>1000
L^2	>1000
L^3	423
L^4	>1000
L^5	>1000
L^6	365
1	>1000
2	>1000
3	>1000
4	>1000
5	>1000
6	>1000
7	>1000
8	>1000
9	>1000
10	430
11	354
12	>1000
13	>1000
14	>1000
15	>1000
16	>1000
17	>1000
18	>1000
19	>1000
20	>1000
21	>1000
22	312
23	406
24	>1000

Table V.  Minimum inhibitory concentration (μg/ml) of the ligands and their metal complexes.

Compound	(a)	(b)	(c)	(d)	(e)	(f)	(g)	(h)	(j)	(k)
L^1	10	–	–	>100	–	–	–	–	–	–
L^2	10	–	–	>100	10	10	–	–	–	–
L^3	10	>100	–	10	>100	–	–	–	–	–
L^4	10	–	–	>100	10	10	–	–	–	10
L^5	–	–	–	–	10	–	–	–	–	–
L^6	>100	–	–	–	–	–	–	–	–	–
1	10	>100	>100	>100	10	10	10	–	>100	25
2	10	25	–	25	>100	>100	>100	>100	10	10
3	10	>100	>100	>100	>100	>100	>100	>100	10	10
4	–	>100	–	>100	10	>100	–	–	25	10
5	10	>100	>100	–	10	25	10	–	10	10
6	>100	>100	25	>100	10	10	–	–	>100	>100
7	10	>100	>100	25	>100	>100	>100	–	10	>100
8	25	>100		–>100	>100	10	>100	10 > 100	10
9	10	–	>100	>100	>100	>100	>100	10	–	>100
10	>100	>100	–	>100	>100	10	>100	–	>100	>100
11	10	–	>100	25	>100	10	–	>100	10	>100
12	>10	–	–	>100	25	>100	–	–	10	>100
13	10	25	25	>100	>100	>100	–	–	>100	>100
14	>100	>100	–	>100	>100	10	>100	>100	>100	10
15	10	25	–	>100	>100	>100	–	>100	>100	25
16	>10	>100	>100	25	>100	10	–	–	>100	>100
17	25	10	>100	>100	>100	10	>100	–	>100	>100
18	25	>100	–	>100	10	>100	25	–	10	>100
19	10	>100	–	>100	10	>100	>100	–	10	10
20	10	10	>100	>100	>100	>100	>100	–	>100	>100
21	>10	>100	>100	>100	>100	–	–	–	>100	>100
22	10	10	25	>100	>100	>100	–	–	>100	25
23	10	10	>100	25	25	>100	>100	–	25	>100
24	>10	10	>100	>100	>100	>100	–	–	>100	>100

(a) = M. tuberculosis, (b) = E. coli, (c) = K. pneumoniae, (d) = P. mirabilis, (e) = P. aeruginosa, (f) = S. typhi, (g) = S. dysenteriae, (h) = B. cereus, (j) = C. diphtheriae, (k) = S. pyogenes. No activity = –.