Synthesis, spectral characterization and microbiological studies of Co(II), Ni(II) and Cu(II) complexes with some novel 20-membered macrocyclic hydrazino-1,2,4-triazole Schiff bases

Figures & data

Figure 1.  Schiff bases used. Where R = H, CH₃, C₂H₅ and C₃H₇.

Table I.  Elemental analyses, magnetic and molar conductance data of Co(II), Ni(II) and Cu(II) complexes of Schiff bases (H₂L^I- H₂L^IV).

		M%		N%		Cl%
Comp.No.	Empirical formula	Obsd.	Calcd.	Obsd.	Calcd.	Obsd.	Calcd.	λm cm^2 Ω^− 1 mol^− 1	μeff (BM)
1	[Co2 (L^I)Cl2].2H2O	16.52	16.57	23.52	23.59	9.78	9.83	22	4.12
2	[Co2 (L^II)Cl2].2H2O	15.91	15.94	22.65	22.70	9.38	9.45	18	4.14
3	[Co2 (L^III)Cl2].2H2O	15.12	15.16	21.48	21.59	8.93	8.99	24	4.22
4	[Co2 (L^IV)Cl2].2H2O	14.75	14.82	21.02	21.10	8.75	8.79	20	4.28
5	[Ni2(L^I)Cl2(H2O)2].2H2O	15.48	15.54	22.46	22.52	9.32	9.38	22	3.16
6	[Ni2(L^II)Cl2(H2O)2].2H2O	14.91	14.98	21.64	21.70	9.01	9.04	19	3.22
7	[Ni2(L^III)Cl2(H2O)2].2H2O	14.22	14.28	20.62	20.68	8.54	8.62	28	3.26
8	[Ni2(L^IV)Cl2(H2O)2].2H2O	13.92	13.97	20.12	20.24	8.40	8.43	21	3.23
9	[Cu2 (L^I)Cl2].2H2O	17.45	17.50	23.27	23.33	9.68	9.72	27	1.44
10	[Cu2 (L^II)Cl2].2H2O	16.86	16.93	22.51	22.58	9.35	9.40	20	1.46
11	[Cu2 (L^III)Cl2].2H2O	16.00	16.03	21.29	21.37	8.88	8.90	18	1.41
12	[Cu2 (L^IV)Cl2].2H2O	15.59	15.67	20.82	20.89	8.67	8.70	24	1.43

Table II.  The important infrared frequencies (in cm⁻¹) of Schiff bases (H₂L^I–H₂L^IV) and their Co(II), Ni(II) and Cu(II) complexes.

Complex No.	H-bonded Phenolic-OH	ν(OH) (Water)	ν(C = N)	ν(NH)	νCH3	Phenolic C-O	ν(M-N)	ν(M-O)	ν(M-Cl)
H2L^I	2748	–	1623	3150	2933	1290	–	–	–
H2L^II	2755	–	1620	3143	2924	1275	–	–	–
H2L^III	2738	–	1625	3140	2935	1295	–	–	–
H2L^IV	2732	–	1628	3146	2928	1286	–	–	–
1	–	3432	1600	3015	2930	1365	455	512	309
2	–	3405	1602	3018	2905	1360	450	525	316
3	–	3411	1610	3010	2910	1364	462	518	320
4	–	3440	1614	3032	2916	1370	444	535	328
5	–	3408	1608	3040	2912	1362	470	554	330
6	–	3430	1610	2995	2908	1368	474	560	321
7	–	3434	1601	3001	2928	1369	456	530	324
8	–	3440	1609	3010	2920	1370	440	542	333
9	–	3435	1603	3026	2922	1363	458	520	318
10	–	3425	1605	3021	2918	1360	449	538	324
11	–	3428	1610	3038	2909	1366	465	566	330
12	–	3438	1612	2998	2917	1361	458	570	313

Table III.  Ligand Field Parameters Of Ni(ii) Complexes Of Schiff Bases (H₂lⁱ–h₂l^iv).

	Transitions (cm^− 1)
Complex No.	ν1	ν2	ν3	ν2 Calcd. cm^− 1	Dq cm^− 1	B^1 cm^− 1	% Distortion	ν2/ν1	LFSE	μeff Calcd. BM	β	β° %
5	9655	15545	25444	15529	965.50	800.57	0.099	1.61	33.10	3.19	0.758	24.188
6	9584	15645	25686	15508	958.40	829.52	0.878	1.63	32.85	3.20	0.786	21.447
7	9764	15774	25554	15663	976.04	795.02	0.706	1.61	33.47	3.19	0.753	24.713
8	9546	15542	25695	15469	954.60	835.13	0.466	1.62	32.72	3.20	0.791	20.916

Dq, B¹ (Racah Parameter), B & β (Nephlauxetic Ratio), LFSE (Ligand Field Stabilization Energy)

Figure 2.  FAB mass spectrum Schiff base (H₂L^II).

Figure 3.  FAB mass spectrum of Ni(II) (5) complex.

Figure 4.  ESR spectrum of Cu(II) (10) complex.

Figure 5.  Thermogravimetric (TG/DTG) curves of Ni(II) (6) complex.

Table IV.  Thermogravimetric data of Co(II) (2), Ni(II) (6) and Cu(II) (10) complexes of Schiff base (H₂L^II).

		Decomposition temperature ^oC	%Weight loss
Complex No.	Empirical formula		Obsd.	Calcd.	Inference
2	[Co2 (L^II)Cl2]·2H2O	115–130	4.828	4.864	Loss of coordinated water molecules
		230–260	35.651	35.675	Loss of aldehyde moieties
		300–320	29.697	29.729	Loss of triazole moieties
6	[Ni2(L^II)Cl2(H2O)2]·2H2O	115–130	4.638	4.651	Loss of coordinated water molecules
		230–260	34.05	34.108	Loss of aldehyde moieties
		300–320	28.425	28.423	Loss of triazole moieties
10	[Cu2 (L^II)Cl2]·2H2O	115–130	4.829	4.838	Loss of coordinated water molecules
		230–260	35.472	35.483	Loss of aldehyde moieties
		300–320	29.561	29.569	Loss of triazole moieties

Figure 6.  Absorption spectrum of Schiff base (H₂L^II).

Table V.  Bacteriological results of Schiff bases derived from 3-substituted-4-amino-5-hydrazino-1,2,4-triazoles and 2-6 diformyl-4-methyl phenol and their Co(II), Ni(II) and Cu(II) complexes.

		Activity against bacteria (mm)^*			Activity against fungi (mm)
Comp. No.	Empirical formula	E. coli	P. aeruginosa	B. cereus	S. aureus	A. niger	A. fumigates
H2L^I	(C22H20N12O2)	08	08	20	08	20	20
H2L^II	(C24H24N12O2)	12	10	16	10	20	20
H2L^III	(C26H28N12O2)	10	12	18	10	18	20
H2L^IV	(C28H32N12O2)	10	10	16	10	20	20
1	[Co2 (L^I)Cl2]·2H2O	08	12	18	08	20	24
2	[Co2 (L^II)Cl2]·2H2O	10	08	12	08	16	16
3	[Co2 (L^III)Cl2]·2H2O	10	12	08	10	18	18
4	[Co2 (L^IV)Cl2]·2H2O	08	10	08	10	18	16
5	[Ni2(L^I)Cl2(H2O)2]·2H2O	08	08	12	08	20	12
6	[Ni2(L^II)Cl2(H2O)2]·2H2O	08	08	12	08	18	20
7	[Ni2(L^III)Cl2(H2O)2]·2H2O	10	10	10	08	20	18
8	[Ni2(L^IV)Cl2(H2O)2]·2H2O	12	08	10	10	20	20
9	[Cu2 (L^I)Cl2]·2H2O	10	08	12	08	20	18
10	[Cu2 (L^II)Cl2]·2H2O	08	10	16	08	22	24
11	[Cu2 (L^III)Cl2]·2H2O	10	12	08	10	20	20
12	[Cu2 (L^IV)Cl2]·2H2O	08	10	10	12	18	18
	Gentamycin	20	20	20	20	–	–
	Fluconazole	–	–	–	–	24	24

* Zone of inhibition (mm).

Figure 7.  (A) Antibacteriogram of Schiff bases; (B) Antifungal screening of Schiff bases; (C) Antibacteriogram of metal complexes; (D) Antifungal screening of metal complexes.

Figure 8.  Square pyramidal geometry of Co(II) and Cu(II) complexes.