Synthesis, characterization and antimicrobial activities of mixed ligand transition metal complexes with isatin monohydrazone Schiff base ligands and heterocyclic nitrogen base

Article abstract of DOI:10.1016/j.saa.2014.07.041

Mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with various uninegative tridentate ligands derived from isatin monohydrazone with 2-hydroxynapthaldehyde/substituted salicylaldehyde and heterocyclic nitrogen base 8-hydroxyquinoline have been s

Full text of DOI:10.1016/j.saa.2014.07.041

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, characterization and antimicrobial activities of mixed ligand
transition metal complexes with isatin monohydrazone Schiff base
ligands and heterocyclic nitrogen base
⇑
Jai Devi , Nisha Batra
Department of Chemistry, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana, India
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
ꢀ
ꢀ
ꢀ
ꢀ
Synthesis and characterization of
Schiff bases and their complexes.
In vitro antimicrobial activity of
compounds.
Biocidal activity of ligands increased
upon coordination with metal ions.
Compound Cu(LIV)(Q)ꢁH2O is found to
be most potent.
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 April 2014
Received in revised form 5 July 2014
Accepted 17 July 2014
Available online 1 August 2014
Mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with various uninegative tridentate ligands
derived from isatin monohydrazone with 2-hydroxynapthaldehyde/substituted salicylaldehyde and
heterocyclic nitrogen base 8-hydroxyquinoline have been synthesized and characterized by elemental
analysis, conductometric studies, magnetic susceptibility and spectroscopic techniques (IR, UV–VIS,
NMR, mass and ESR). On the basis of these characterizations, it was revealed that Schiff base ligands existed
as monobasic tridentate ONO bonded to metal ion through oxygen of carbonyl group, azomethine nitrogen
and deprotonated hydroxyl oxygen and heterocyclic nitrogen base 8-hydroxyquinoline existed as monoba-
sic bidentate ON bonded through oxygen of hydroxyl group and nitrogen of quinoline ring with octahedral
or distorted octahedral geometry around metal ion. All the compounds have been tested in vitro against var-
ious pathogenic Gram positive bacteria, Gram negative bacteria and fungi using different concentrations
Keywords:
Antimicrobial
8-Hydroxyquinoline
Octahedral
Tridentate
(25, 50, 100, 200 lg/mL) of ligands and their complexes. Comparative study of antimicrobial activity of
ligands, and their mixed complexes indicated that complexes exhibit enhanced activity as compared to free
ligands and copper(II) Cu(LIV)(Q)ꢁH2O complex was found to be most potent antimicrobial agent.
Ó 2014 Published by Elsevier B.V.
Introduction
in many areas of modern medicine. In this regard, mixed ligand
metal complexes play an important role in the activation of
The therapeutic and diagnostic properties of transition metal
complexes have attracted attention leading to their application
enzymes and display good nucleolytic cleavage activity. Mixed
ligand complexes are used for storage as well as for transport
of active material through membrane [1]. Among the important
pharmacophores responsible for biological activity, the isatin
scaffold is viable lead structure for the synthesis of efficient
⇑
Corresponding author.
E-mail address: jaidevi_gju@yahoo.com (J. Devi).
http://dx.doi.org/10.1016/j.saa.2014.07.041
1386-1425/Ó 2014 Published by Elsevier B.V.

J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
711
chemotherapeutic agent [2]. Schiff bases derived from isatin
Experimental
exhibit many neurophysiological and neuropharmacological
effects like antimicrobial, antiviral, anticonvulsant, anticancer,
antimycobacterial, antimalarial, cysticidal, herbicidal and anti-
inflammatory activity [3–8]. They also have anti-HIV, antiproto-
zoal and antihelminthic activities [9–12]. Recently they have
found application as enzyme inhibitors in the inhibition of cys-
teine and serine proteases [13]. Incited by this and as a part of
our work on isatin derivatives, we reported the synthesis of novel
mixed ligand transition metal complexes derived from isatin
monohydrazone with 2-hydroxynapthaldehyde/substituted sali-
cylaldehyde and heterocyclic nitrogen base 8-hydroxyquinoline.
These compounds were characterized by elemental analysis,
conductometric studies, magnetic susceptibility and spectroscopic
techniques (IR, UV–VIS, NMR, Mass and ESR) and evaluated for
antimicrobial activity with an expectation to find some novel
and potential antimicrobial agent.
Materials and methods
All the chemicals used in the present investigation were of Ana-
lytical grade. Metal salts as nitrates obtained from Aldrich and
were used as such without any further purification. Elemental
analysis (C, H and N) of samples was carried out by using Perkin
Elmer 2400 instrument. Metal contents determined using standard
gravimetric methods, cobalt as cobalt pyridine thiocyanate, nickel
as nickel dimethylglyoximate, copper as cuperous thiocyanate and
zinc as zinc ammonium phosphate [14]. IR spectra were recorded
on Shimadzu IR affinity-I 8000 FT-IR spectrometer using KBr disc.
1H NMR and 13C NMR were recorded on Bruker Avance II
300 MHz NMR spectrometer and all chemical shifts were reported
in parts per million relative to TMS as internal standard in CDCl3.
UV spectra were recorded on UV–VIS–NIR Varian Cary-5000
NNH2
O
O
EtOH
Reflux, 3h
O
NH NH2. H2O
+
2
N
H
N
H
CHO
OH
NH
HLI =
HLII =
CH3
Br
NO2
H
H
H
HLIII
HLIV
=
=
N
N
HC
O
OH
HLI-HLIV
OH
N
N
NH
N
HC
M(NO3)2. xH2O
+
+
O
OH
HQ
HLI-HLIV
H
N
O
M
N
N
O
+
(x-1)H O 2HNO
2
3
+
HC
N
O
H2O
M = Co(II), Ni(II),Cu(II) and Zn(II)
x = 1,6
Scheme 1.

712
J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
M(NO ) . xH O
HLI-IV
2HNO
+
HQ
(x-1) H O
+
2
+
M(LI-IV)(Q).H2O
+
3 2
2
3
Scheme 2. Reaction scheme for the synthesis of metal complexes.
spectrometer in DMF. Magnetic susceptibilities of complexes were
measured by Gouy’s method, using Hg [Co(SCN)4] as the calibrant
at room temperature. Mass spectra were recorded on a API 2000
(Applied Biosystems) mass spectrometer equipped with an electro-
spray source and a Shimadzu Prominence LC. Powder XRD of sam-
evaporation of solvent was filtered, washed with methanol, recrys-
tallized from same solvent and dried under vacuum (yield 70%).
Synthesis of metal complexes
ples were carried out on Rigaku-miniflex-II with Cu K
source of radiation.
a (1.54 Å), a
Aqueous solution (15 mL) of metal salt, M(NO3)2ꢁxH2O (5 mmol)
was added to hot methanolic solution (20 mL) of Schiff base
ligands (HLI–IV) (5 mmol) with constant stirring and then added
methanolic solution of 8-hydroxyquinoline (HQ) (0.72 g, 5 mmol).
Sodium hydroxide was added to maintain the pH of solution. The
resulting solution was refluxed for 4 h, separated complex was fil-
tered, washed thoroughly with methanol followed by petroleum
ether to remove unreacted metal nitrates or ligands and then dried
in vacuum over fused calcium chloride (Scheme 1).
Synthesis of Schiff base ligands
Isatin monohydrazone was synthesized by reacting ethanolic
solution (30 mL) of isatin (4.41 g, 30 mmol) with hydrazine
hydrate (0.15 g, 30 mmol) in ethanol (10 mL). The mixture was
refluxed for 3 h on water bath and allowed to cool at room temper-
ature. The yellow compound formed was filtered, washed, dried
and recrystallized from ethanol (mp. 225 °C, yield 90%).
Pharmacology
Schiff base ligands used in present investigation were prepared
by reacting hot methanolic solution (20 mL) of 2-hydroxynapthal-
dehyde/5-substituted salicylaldehyde (10 mmol) with methanolic
solution (10 mL) of isatin monohydrazone (10 mmol) with con-
stant stirring. The resulting mixture was refluxed for 5 h with
few drops of glacial acetic acid. The product obtained after the
Schiff base ligands HLI–IV, ligand HQ and their mixed ligand
transition metal(II) complexes were assessed for antimicrobial
activity against Gram positive bacteria viz. Bacillus subtilis (MTCC
No. 1790), Micrococcus luteus (MTCC No. 4821); Gram negative bac-
teria viz. Pseudomonas aeruginosa (MTCC No. 9126), Pseudomonas
Table 1
Analytical data of ligands and their mixed transition metal(II) complexes.
Compounds
Mol. formula (mol.wt.)
Yield (%)
M.pt. (°C)
Color
Found (calcd) (%)
m/z
(
XM) ꢂ 10ꢃ3
C
H
N
M
–
HLI
C19H13N3O2
(315.33)
C16H13N3O2
(279.29)
C15H10N3O2Br
(344.16)
C15H10N4O4
(310.26)
C28H20N4O4Co
(535.42)
C28H20N4O4Ni
(535.18)
C28H20N4O4Cu
(540.03)
C28H20N4O4Zn
(541.87)
C25H20N4O4Co
(499.38)
C25H20N4O4Ni
(499.14)
C25H20N4O4Cu
(504.00)
C25H20N4O4Zn
(505.84)
C24H17N4O4BrCo
(564.25)
C24H17N4O4BrNi
(564.01)
C24H17N4O4BrCu
(568.87)
C24H17N4O4BrZn
(570.71)
75
78
73
79
58
52
55
60
57
55
60
54
55
57
59
54
55
61
53
58
220
Red
72.13
4.47
13.65
316.2
279.9
344.8
310.6
535.8
535.6
539.2
541.5
499.8
499.6
504.6
505.1
564.8
564.9
568.2
571.3
530.9
530.7
535.4
537.2
–
(72.37)
68.42
(68.81)
52.59
(52.35)
58.49
(58.07)
63.04
(62.81)
63.01
(62.84)
62.53
(62.27)
62.32
(62.06)
60.42
(60.13)
60.43
(60.16)
59.83
(59.58)
59.65
(59.36)
51.34
(51.09)
51.45
(51.11)
50.94
(50.67)
50.84
(50.51)
54.67
(4.16)
4.94
(4.69)
3.24
(2.93)
3.74
(3.25)
3.97
(3.77)
3.53
(3.77)
4.01
(3.73)
3.97
(3.72)
4.53
(4.04)
4.31
(4.04)
4.19
(4.00)
4.16
(3.99)
3.34
(3.04)
3.28
(3.04)
3.43
(3.01)
3.24
(3.00)
3.48
(13.33)
15.38
(15.05)
12.48
(12.21)
18.23
(18.06)
10.74
(10.46)
10.73
(10.47)
10.14
(10.37)
10.59
(10.34)
11.45
(11.22)
11.54
(11.22)
11.54
(11.12)
11.32
(11.08)
10.05
(9.93)
9.79
(9.93)
10.04
(9.85)
10.14
(9.82)
13.45
HLII
185
Orange
Brown
Light yellow
Green
–
–
–
–
HLIII
168
–
HLIV
215
–
Co(LI)(Q)ꢁH2O
Ni(LI)(Q)ꢁH2O
Cu(LI)(Q)ꢁH2O
Zn(LI)(Q)ꢁH2O
Co(LII)(Q)ꢁH2O
Ni(LII)(Q)ꢁH2O
Cu(LII)(Q)ꢁH2O
Zn(LII)(Q)ꢁH2O
Co(LIII)(Q)ꢁH2O
Ni(LIII)(Q)ꢁH2O
Cu(LIII)(Q)ꢁH2O
Zn(LIII)(Q)ꢁH2O
Co(LIV)(Q)ꢁH2O
Ni(LIV)(Q)ꢁH2O
Cu(LIV)(Q)ꢁH2O
Zn(LIV)(Q)ꢁH2O
>298d
>300d
>287d
>300d
>294d
>296d
>294d
>300d
>285d
>299d
>300d
>300d
>296d
>297d
>295d
>294d
11.54
(11.01)
11.02
(10.97)
11.56
(11.77)
12.43
(12.07)
12.04
(11.80)
11.95
(11.76)
12.94
(12.61)
13.04
(12.93)
10.67
(10.44)
10.74
(10.41)
11.24
(11.17)
11.67
(11.46)
11.45
(11.11)
11.43
(11.07)
12.04
(11.88)
12.43
8.4
6.3
4.7
6.9
8.4
5.6
7.2
7.6
8.5
7.8
6.4
6.9
9.2
11.0
9.3
6.5
Brown
Green
Color-less
Green
Brown
Green
Color-less
Green
Brown
Green
Color-less
Green
C24H17N5O6Co
(530.35)
C24H17N5O6Ni
(530.12)
C24H17N5O6Cu
(534.97)
C24H17N5O6Zn
(536.81)
(54.35)
54.87
(54.38)
54.03
(53.88)
53.94
(53.70)
(3.23)
3.45
(3.23)
3.47
(3.20)
3.54
(3.19)
(13.21)
13.54
(13.21)
13.28
(13.09)
13.43
(13.05)
Brown
Green
Color-less
(12.18)
d = Decomposition temperature.

J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
713
Table 2
1H and 13C NMR spectral characteristics (d) of isatin monohydrazone Schiff base ligands and 8-hydroxyquinoline.
6
5
OH
8''
7
4
N
9"
8
9
3
2''
3''
7''
6''
5'
6'
1'
N
NH
5'
6'
H
N
5'
HC
10"
4'
2
HLII= CH3
4'
5''
HLI =
2'
O
3'
Br
HLIII
HLIV
=
=
H
OH
HQ
6'
HLI-HLIV
NO2
H
Ligands 1H NMR (CDCl3) d in ppm
13C NMR (CDCl3) d in ppm
HLI
13.95 (s, 1H, OH), 11.04 (s, 1H, CH), 9.81 (s, 1H, NH), 7.89 (d, 1H, C4AH,
J = 7.92 Hz), 7.12 (t, 1H, C5AH), 7.60 (t, 1H, C6AH), 8.46 (d, 1H, C7AH,
J = 8.28 Hz), 8.05 (d, 1H, C03AH, J = 9.08 Hz), 7.18 (d, 1H, C04AH, J = 9.08 Hz),
7.68 (d, 1H, C05AH, J = 7.44 Hz), 7.46 (q, C60 AH, C70 AH), 6.94 (d, C80 AH,
J = 7.76 Hz)
164.97 (@N), 162.29 (CH@N), 159.57 (C@O), 110.80 (C4), 120.90 (C5), 120.38
(C6), 119.81(C7), 144.13(C8), 123.99(C9), 108.22 (C01), 148.34 (C20 ), 127.41 (C30 ),
133.36 (C04), 128.32 (C50 ), 132.61 (C60 ), 122.26 (C07), 122. 11 (C80 ), 136.78 (C09),
128.99 (C010
)
HLII
HLIII
HLIV
HQ
13.38 (s, 1H, OH), 10.95 (s, 1H, CH), 9.69 (s, 1H, NH), 7.83 (d, 1H, C4AH,
J = 7.28 Hz), 7.15 (t, 1H, C5AH), 7.62 (t, 1H, C6AH), 8.38 (d, 1H, C7AH,
J = 9.02 Hz), 7.43 (d, 1H, C03AH, J = 7.26 Hz), 7.41 (d, 1H, C04AH, J = 8.42 Hz),
7.52 (s, 1H, C06AH)
13.52 (s, 1H, OH), 11.26 (s, 1H, CH), 9.70 (s, 1H, NH), 7.86 (d, 1H, C4AH,
J = 6.84 Hz), 7.18 (t, 1H, C5AH), 7.61 (t, 1H, C6AH), 8.39 (d, 1H, C7AH,
J = 7.02 Hz), 7.74 (d, 1H, C03AH, J = 9.34 Hz), 8.30 (d, 1H, C04AH, J = 7.18 Hz),
8.40 (s, 1H, C06AH)
13.49 (s, 1H, OH), 11.13 (s, 1H, CH), 9.72 (s, 1H, NH), 7.82 (d, 1H, C4AH,
J = 9.02 Hz), 7.23 (t, 1H, C5AH), 7.58 (t, 1H, C6AH), 8.48 (d, 1H, C7AH,
J = 8.38 Hz), 7.82 (d, 1H, C03AH, J = 9.02 Hz), 8.36 (d, 1H, C04AH, J = 7.38 Hz),
7.68 (s, 1H, C06AH)
164.72 (C@N), 161.93 (CH@N), 159.05 (C@O), 111.09 (C4), 121.84 (C5), 120.27
(C6), 120.31 (C7), 144.01 (C8), 124.08 (C9), 109.42 (C01), 148.21 (C20 ), 127.30
(C30 ), 132.94 (C04), 130.04 (C50 ), 131.22 (C60 ), 20.09 (ACH3)
164.53 (C@N), 162.02 (CH@N), 159.24 (C@O), 111.78 (C4), 122.01 (C5), 120.78
(C6), 120.67 (C7), 144.19 (C8), 124.19 (C9), 109.43 (C01), 148.37 (C20 ), 127.63
(C03), 133.08 (C04), 129.12 (C50 ), 131.58 (C60 )
164.95 (C@N), 162.31 (CH@N), 159.21 (C@O), 111.13 (C4), 122.06 (C5), 120.74
(C6), 120.62 (C7), 144.37 (C8), 124.85 (C9), 109.15 (C01), 148.47 (C20 ), 127.78
(C03), 133.25 (C04), 141.19 (C50 ), 132.08 (C60 )
12.92 (s, 1H, OH), 8.84 (d, 1H, C020 AH, J = 9.02 Hz), 7.28 (t, 1H, C003AH), 7.99 (d, 150.30 (C002), 125.64 (C003), 137.40 (C004), 120.42 (C005), 128.92 (C006), 116.40
1H, C004AH, J = 8.04 Hz), 7.36 (d, 1H, C005AH, J = 8.28 Hz), 7.28 (t, 1H, C006AH),
7.01 (d, 1H, C007AH, J = 9.18 Hz)
(C007), 153.74 (C008), 138.81 (C009), 130.52 (C00
)
10
Table 3
1H and 13C NMR spectral characteristics (d) of zinc(II) complexes of isatin monohydrazone Schiff base ligands and 8-hydroxyquinoline.
Complexes
1H NMR (CDCl3) d in ppm
13C NMR (CDCl3) d in ppm
Zn(LI)(Q)H2O
11.22 (s, 1H, ACH), 9.80 (s, 1H, NH), 7.92 (d, 1H, C4AH, J = 6.34 Hz), 7.12 (t, 166.84 (C@N), 164.40 (ACH@N), 161.89(C@O), 111.72(C4), 121.04 (C5),
1H, C5AH), 7.60 (t, 1H, C6AH), 8.46 (d, 1H, C7AH, J = 7.04 Hz), 8.18 (d, 1H, 120.54 (C6), 120.04(C7), 145.13(C8), 124.08 (C9), 109.21 (C01), 150.02 (C20 ),
C03AH, J = 8.24 Hz), 7.20 (d, 1H, C40 AH, J = 7.10 Hz), 7.70 (d, 1H, C05AH,
J = 8.20 Hz), 7.46 (q, C06AH, C70 AH), 6.93 (d, C08AH, J = 7.42 Hz), 8.95 (d, 1H,
C020 AH, J = 6.45 Hz), 7.30 (t, 1H, C300 AH), 7.99 (d, 1H, C040 AH, J = Hz), 7.36 (d,
1H, C500 AH, J = 6.04 Hz), 7.28 (t, 1H, C600 AH), 7.01(d, 1H, C070 AH, J = 8.04 Hz),
3.54 (s, 2H, H2O)
128.04 (C030 ), 133.65 (C40 ), 128.32 (C50 ), 132.61 (C60 ), 122.26 (C70 ), 122. 11
(C08), 136.78 (C09), 128.99 (C10), 153.48 (C020 ), 125.93 (C300 ), 138.01 (C040 ),
00
120.98 (C050 ), 129.04 (C600 ), 117.65(C700 ), 155.01 (C800 ), 138.98 (C090 ), 131.04 (C
)
10
Zn(LII)(Q)H2O
11.15 (s, 1H, ACH), 9.69 (s, 1H, NH), 7.83 (d, 1H, C4AH, J = 7.05 Hz), 7.15 (t, 165.94 (C@N), 162.06 (ACH@N), 160.72 (C@O), 111.74 (C4), 122.03 (C5),
1H, C5AH), 7.60 (t, 1H, C6AH), 8.42 (d, 1H, C7AH, J = 8.24 Hz), 7.52 (d, 1H, 120.74 (C6), 120.31 (C7), 145.00 (C8), 124.82 (C9), 109.82 (C01), 150.04 (C20 ),
C03AH, J = 6.40 Hz), 7.42 (d, 1H, C04AH, J = 8.34 Hz), 7.52 (s, 1H, C06AH), 8.92
(d, 1H, C020 AH, J = 8.03 Hz), 7.28 (t, 1H, C300 AH), 7.99 (d, 1H, C040 AH,
J = 4.32 Hz), 7.54 (d, 1H, C050 AH, J = 8.28 Hz), 7.30 (t, 1H, C06AH), 7.14 (d, 1H,
C070 AH, J = 9.18 Hz), 3.52 (s, 2H, H2O)
127.57 (C030 ), 133.01 (C04), 130.16 (C50 ), 132.04 (C60 ), 20.09 (ACH3), 152.48
(C020 ), 125.43 (C300), 137.83 (C400 ), 121.84 (C050 ), 129.02 (C600 ), 116.40 (C070 ), 154.83
(C080 ), 138.94 (C090 ), 130.86 (C
)
00
10
Zn(LIII)(Q)H2O 11.45 (s, 1H, ACH), 9.70 (s, 1H, NH), 7.87 (d, 1H, C4AH, J = 6.93 Hz), 7.20 (t, 165.84 (C@N), 163.48 (ACH@N), 161.08 (C@O), 111.93 (C4), 122.18 (C5),
1H, C5AH), 7.61 (t, 1H,C6AH), 8.39 (d, 1H, C7AH, J = 8.14 Hz), 7.93 (d, 1H, 120.78 (C6), 120.67 (C7), 145.04 (C8), 124.74 (C9), 109.43 (C01), 150.03 (C20 ),
C03AH, J = 9.02 Hz), 8.31 (d, 1H, C04AH, J = 8.02 Hz), 8.44 (s, 1H, C06AH), 8.98
(d, 1H, C020 AH, J = 4.27 Hz), 7.29 (t, 1H, C300 AH), 7.97 (d, 1H, C040 AH,
J = 8.04 Hz), 7.37 (d, 1H, C050 AH, J = 8.04 Hz), 7.28 (t, 1H, C060 AH), 7.03(d, 1H,
C070 AH, J = 8.04 Hz), 3.54 (s, 2H, H2O)
127.92 (C03), 133.19 (C40 ), 129.84 (C50 ), 131.82 (C06), 151.07 (C200 ), 125.64 (C030 ),
137.58 (C400 ), 120.42 (C500 ), 128.92 (C600 ), 116.40 (C070 ), 154.32 (C800), 138.98 (C090 ),
00
130.23 (C
)
10
Zn(LIV)(Q)H2O 11.34 (s, 1H, ACH), 9.71 (s, 1H, NH), 7.84 (d, 1H, C4AH, J = 6.38 Hz), 7.24 (t, 167.08 (C@N), 164.01 (CH@N), 162.04 (C@O), 111.45 (C4), 122.83 (C5),
1H, C5AH), 7.60 (t, 1H, C6AH), 8.49 (d, 1H, C7AH, J = 9.02 Hz), 7.92 (d, 1H, 120.74 (C6), 120.62 (C7), 145.23 (C8), 125.01 (C9), 109.15 (C01), 150.01
C03AH, J = 8.04 Hz), 8.35 (d, 1H, C04AH, J = 4.14 Hz), 7.69(s, 1H, C06AH), 8.97
(d, 1H, C020 AH, J = 4.44 Hz), 7.28 (t, 1H, C300 AH), 7.99 (d, 1H, C040 AH,
J = 9.02 Hz), 7.35 (d, 1H, C050 AH, J = 9.03 Hz), 7.28 (t, 1H, C060 AH), 7.01 (d, 1H,
C070 AH, J = 7.12 Hz), 3.52 (s, 2H, H2O)
(C20 ), 127.89 (C30 ), 133.53 (C40 ), 141.19 (C50 ), 132.08 (C60 ), 153.01 (C200 ), 125.93
(C030 ), 137.52 (C400), 120.42 (C500 ), 128.92 (C060 ), 116.40 (C700), 155.83 (C080 ), 138.81
(C090 ), 130.64 (C
)
00
10
mendocina (MTCC No. 7094) and fungi Verticillum dahlia (MTCC No.
2063), Cladosporium herbarium (MTCC No. 351), Trichophyton
soudanense (MTCC No.7859) by agar plate disc diffusion method.
The bacteria and fungi were subcultured on Nutrient agar and sab-
ouraud dextrose agar, respectively. The experimental values were
compared with standard drugs i.e. Streptomycin for antibacterial
activity and Fluconazole for antifungal activity.
Antibacterial activity assay
For in vitro antibacterial activity, stock solution was prepared by
dissolving compound in minimum amount of DMSO. Target micro-
organism cultures were prepared separately in 15 mL of liquid
nutrient broth for activation. Inoculation was done with the help
of micropipette with sterilized tips, 100
was placed onto the surface of agar plate, spread over the whole
lL of activated strain

714
J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
Table 4
Electronic absorption spectral data and magnetic moment
hydroxyquinoline.
(l) of mixed ligand transition metal(II) complexes of isatin monohydrazone Schiff base ligands and 8-
Complexes
Absorption (cmꢃ1
)
Band assignment
B value
b value
t2/
t1
Geometry
l (BM)
Co(LI)(Q) H2O
24,730
17,010
8820
24,820
15,324
9734
24,325
15,480
23,550
24,650
17,105
8846
24,730
15,448
9830
24,530
15,410
23,825
24,545
17,180
8835
24,310
15,430
9856
24,432
15,370
23,710
24,810
17,110
8830
24,535
15,370
9760
4T1g(F) ? 4T1g(P)
4T1g(F) ? 4A2g(F)
4T1g(F) ? 4T2g(F)
3A2g(F) ? 3T1g(P)
3A2g(F) ? 3T1g(F)
3A2g(F) ? 3T2g(F)
623
–
–
729
–
–
0.64
–
–
0.70
–
–
1.92
–
–
1.57
–
–
Octahedral
–
–
Octahedral
–
–
Distorted
Octahedral
Octahedral
Octahedral
–
–
Octahedral
–
–
Distorted
Octahedral
Octahedral
Octahedral
–
4.34
–
–
3.06
–
–
Ni(LI)(Q)H2O
Cu(LI)(Q)H2O
p
N ? Cu⁄
1.87
2Eg(D) ? 2T2g(D)
LMCT
Zn(LI)(Q)H2O
Co(LII)(Q) H2O
4T1g(F) ? 4T1g(P)
4T1g(F) ? 4A2g(F)
4T1g(F) ? 4T2g(F)
3A2g(F) ? 3T1g(P)
3A2g(F) ? 3T1g(F)
3A2g(F) ? 3T2g(F)
613
–
–
712
–
–
0.63
–
–
0.69
–
–
1.93
–
–
1.57
–
–
4.21
–
–
3.04
–
–
Ni(LII)(Q)H2O
Cu(LII)(Q)H2O
p
N ? Cu⁄
1.75
2Eg(D) ? 2T2g(D)
LMCT
Zn(LII)(Q)H2O
Co(LIII)(Q) H2O
4T1g(F) ? 4T1g(P)
4T1g(F) ? 4A2g(F)
4T1g(F) ? 4T2g(F)
3A2g(F) ? 3T1g(P)
3A2g(F) ? 3T1g(F)
3A2g(F) ? 3T2g(F)
602
–
–
678
–
–
0.62
–
–
0.65
–
–
1.94
–
–
1.56
–
–
4.38
–
–
3.01
–
–
–
Ni(LIII)(Q)H2O
Cu(LIII)(Q)H2O
Octahedral
–
–
Distorted
Octahedral
Octahedral
Octahedral
–
p
N ? Cu⁄
1.86
2Eg(D) ? 2T2g(D)
LMCT
Zn(LIII)(Q)H2O
Co(LIV)(Q) H2O
4T1g(F) ? 4T1g(P)
4T1g(F) ? 4A2g(F)
4T1g(F) ? 4T2g(F)
3A2g(F) ? 3T1g(P)
3A2g(F) ? 3T1g(F)
3A2g(F) ? 3T2g(F)
623
–
–
708
–
–
0.64
–
–
0.68
–
–
1.93
–
–
1.57
–
–
4.43
–
–
3.08
–
–
–
Ni(LIV)(Q)H2O
Octahedral
–
–
Cu(LIV)(Q)H2O
Zn(LIV)(Q)H2O
24,588
15,450
23,926
p
N ? Cu⁄
Distorted
Octahedral
Octahedral
1.92
2Eg(D) ? 2T2g(D)
LMCT
–
–
–
–
surface and then two wells having diameter of 10 mm were dug in
media. In each well of inoculated agar plate, 100 L of sterilized
100
l
g/ml. The stock solution (0.1 mL) was added to 1.8 mL of ster-
l
ile nutrient broth to form the first dilution (50 lg/mL). One mL of
stock solution was poured and incubated at 37 °C for 48 h. Activity
was determined by measuring the diameter of zone showing com-
plete inhibition and has been expressed in mm.
the solution from first dilution was diluted further with one mL
of the sterile double strength nutrient broth to produce the second
dilution. The process was repeated until a set of five dilutions with
test compound concentrations of 50, 25, 12.5, 6.25 and 3.12
lg/mL
was obtained. The MIC of standard drugs for antibacterial activity
and antifungal activity were found to be <3.12 lg/mL.
Antifungal activity assay
For in vitro antifungal activity, the moulds were grown on sab-
ouraud dextrose agar (SDA) at 25 °C for 7 days and used as inocu-
Results and discussion
late. 15 mL of molten SDA (45 °C) was added to 100
lL volume of
each compound having concentration of 100 g/mL, reconstituted
l
Mixed ligand transition metal(II) complexes were obtained by
reaction of transition metal salts M(NO3)2ꢁxH2O [M@Co(II), Ni(II),
Cu(II) and Zn(II); x = 1,6] with isatin monohydrazone Schiff base
ligands 3-[(2-hydroxy-naphthalen-1-ylmethylene)-hydrazono]-1,
3-dihydro-indol-2-one (HLI), 3-[(2-hydroxy-5-methyl-benzyli-
dene)-hydrazono]-1,3-dihydro-indol-2-one (HLII), 3-[(5-Bromo-2-
hydroxy-benzylidene)-hydrazono]-1,3-dihydro-indol-2-one (HLIII),
3-[(2-hydroxy-5-nitro-benzylidene)-hydrazono]-1,3-dihydro-
indol-2-one (HLIV) and other ligand heterocyclic nitrogen base
8-hydroxyquinoline (HQ).
in the DMSO, poured into a sterile Petri plate and allowed to solid-
ify at room temperature. The solidified poisoned agar plates were
inoculated at the centre with fungal plugs 10 mm obtained from
actively growing colony and incubated at 25 °C for 7 days. DMSO
was used as negative control and Fluconazole was used as positive
control to access antifungal activity. Diameters of the fungal colo-
nies were measured and expressed as percent mycelial inhibition
determined by the following formula.
Inhibition of mycelial growth % ¼ ðdc ꢃ dtÞ=dc ꢂ 100
dc – average diameter of fungal colony in negative control; dt – aver-
age diameter of fungal colony in experimental plates.
Table 5
ESR spectral data of mixed ligand copper(II) complexes of isatin monohydrazone
Schiff base ligands and 8-hydroxyquinoline.
Determination of minimum inhibitory concentration (MIC)
Complexes
g||
g\
gav
G
k (–) a2
b2
K||
K\
MIC is the lowest concentration of a compound that will inhibit
the visible growth of microbes after overnight incubation. MIC of
synthesized compounds were determined by means of two fold
serial dilution technique. The stock solution of the test compound
was prepared in dry dimethylsulfoxide to give a concentration of
Cu(LI)(Q)H2O
Cu(LII)(Q)H2O
Cu(LIII)(Q)H2O 2.32 2.09 2.16 3.62 614
Cu(LIV)(Q)H2O 2.1 2.08 2.15 3.96 579
2.31 2.09 2.16 3.50 619
2.29 2.08 2.15 3.70 577
0.67 0.91 0.96 1.09
0.65 0.92 0.96 1.03
0.66 0.93 0.99 1.09
0.65 0.92 1.02 1.02

J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
715
The metal nitrates reacted with mixed ligands according to fol-
lowing proposed general equation (see Scheme 2).
MðNO3Þ2 ꢁ xH2O þ HLI—IV þ HQ ! MðLI—IVÞðQÞ ꢁ H2O þ ðx ꢃ 1ÞH2O
þ 2HNO
All the complexes were obtained as solids, insoluble in most of
the organic solvents except DMF and DMSO. The homogeneity of
the ligands and their metal complexes was checked by TLC. The
low molar conductance values for 1 ꢂ 10ꢃ3 M complexes were
found to be in the range of 4.7–11.0
X
ꢃ1 cm2 molꢃ1 in dry DMSO
indicating non-electrolytic nature of complexes (Table 1). The ste-
reochemistry of these metal complexes was determined by spec-
troscopic techniques (IR, NMR, electronic, ESR and mass) and
magnetic susceptibility measurements.
IR spectra
In order to find binding modes of Schiff base ligands and 8-
hydroxyquinoline with transition metal ions, IR spectra of com-
pounds were recorded. On comparison of IR spectra of Schiff base
ligands HLI–IV, HQ and their metal complexes bands at 1573–
1585 cmꢃ1 and 1703–1710 cmꢃ1 in Schiff base ligands HLI–IV due
Fig. 1. ESR spectra of Cu(LI)(Q)ꢁH2O complex at 300 K.
to aldimine
m(C@N) and m(C@O) groups respectively was shifted
by 15–25 cmꢃ1 to lower frequency on complexation indicated
involvement of nitrogen of aldimine group in chelation and coordi-
nation of carbonyl oxygen of isatin ring to metal ion [15]. The band
corresponding to ketimine
m(C@N) moiety observed at 1680–
1684 cmꢃ1 almost remains unaffected, showed its non bonded
state with metal ion [16]. Hydroxyl oxygen coordinated to metal
ion with deprotonation was evidenced by disappearance of band
3360–3385 cmꢃ1 due to AOH group in ligands. There was no
change in the position of ANH stretching band of isatin ring, con-
firms the nonparticipation of ANH group in coordination. How-
ever, the coordination of HQ was confirmed by disappearance of
band at 3420 cmꢃ1 due to hydroxyl group and shifting of
band of quinoline ring from 1575 cmꢃ1 to 1548–1562 cmꢃ1
m(C@N)
.
Fig. 2. XRD of complex Co(LI)(Q)ꢁH2O.
Table 6
The in vitro antibacterial activity of isatin monohydrazone Schiff base ligands, 8-hydroxyquinoline and their mixed ligand transition metal(II) complexes.
Sr. No
Compounds
Zone of Inhibition (mm)
Gram+ve
Gram–ve
B. subtilis
M. Luteus
P.aeruginosa
P. mendocina
25
50
100
200
25
50
100
200
25
50
100
200
25
50
100
200
1
2
3
4
5
6
7
8
HLI
HLII
HLIII
HLIV
9
8
10
11
8
10
9
11
11
8
10
11
12
12
10
16
16
18
14
13
14
16
12
16
16
16
14
16
17
20
15
25
11
12
12
13
11
16
18
20
16
15
16
18
14
17
17
19
16
18
19
22
17
26
10
8
9
11
9
10
8
9
11
10
10
12
10
16
17
17
15
14
15
16
13
16
16
17
16
17
16
18
16
23
12
11
11
13
11
18
19
20
17
15
16
19
15
16
18
20
17
19
18
21
18
25
10
9
9
10
8
11
10
11
12
9
11
10
12
12
10
15
16
19
16
16
17
17
13
16
15
17
15
16
17
20
16
25
12
10
11
13
10
17
18
21
18
16
18
19
15
17
18
20
17
19
19
22
18
28
10
11
9
11
8
11
8
11
10
11
14
10
16
17
20
17
15
18
19
14
16
18
19
17
17
18
22
17
27
12
11
13
14
11
18
19
22
19
17
19
21
16
19
19
21
18
18
20
24
19
30
11
12
10
15
16
18
16
15
16
17
14
14
16
19
15
17
18
19
16
25
12
10
14
16
17
15
14
15
16
13
15
16
17
15
17
16
18
15
20
HQ
Co(LI)(Q) H2O
Ni(LI)(Q)H2O
Cu(LI)(Q)H2O
Zn(LI)(Q)H2O
Co(LII)(Q) H2O
Ni(LII)(Q)H2O
Cu(LII)(Q)H2O
Zn(LII)(Q)H2O
Co(LIII)(Q) H2O
Ni(LIII)(Q)H2O
Cu(LIII)(Q)H2O
Zn(LIII)(Q)H2O
Co(LIV)(Q) H2O
Ni(LIV)(Q)H2O
Cu(LIV)(Q)H2O
Zn(LIV)(Q)H2O
Streptomycin
14
14
16
13
12
12
14
11
13
14
15
12
15
15
17
14
19
15
15
18
14
13
14
16
12
14
16
16
14
16
15
19
15
21
14
14
16
14
13
12
15
12
13
14
15
12
14
15
17
13
19
14
13
15
14
13
13
15
12
13
14
16
12
14
15
17
14
20
14
15
17
16
15
15
17
13
14
15
17
13
16
17
19
16
23
14
15
16
14
14
15
16
13
14
14
17
13
15
15
18
14
22
9
10
11
12
13
14
15
16
17
18
19
20
21
22

716
J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
Table 7
The in vitro antifungal activity of isatin monohydrazone Schiff base ligands, 8-hydroxyquinoline and their mixed ligand transition metal(II) complexes.
Sr. No
Compounds
Mycelial growth Inhibition (%)
V. dahliae
C. herbarium
T. soudanense
25
50
100
200
25
50
100
200
25
50
100
200
1
2
3
4
5
6
7
8
HLI
HLII
HLIII
HLIV
46.4
44.8
45.1
47.3
42.3
53.4
53.3
54.1
52.4
50.1
50.7
52.3
49.3
50.8
51.4
5.9
47.9
45.6
46.8
48.4
44.8
54.8
53.9
55.8
53.6
52.0
51.9
53.1
50.2
52.6
53.1
54.6
52.6
53.2
53.2
56.1
54.2
79.4
49.2
47.3
48.5
50.2
46.4
55.4
55.8
57.6
54.3
52.9
52.4
54.9
52.3
54.3
54.9
56.1
53.2
54.8
53.9
57.9
55.3
79.8
50.4
49.8
49.9
51.5
48.9
56.8
56.6
59.2
55.8
54.2
54.4
56.2
53.8
55.8
56.0
57.4
54.7
55.2
54.8
59.6
56.2
81.2
45.7
43.9
44.1
46.8
42.3
50.9
51.2
53.3
50.1
51.5
51.8
52.2
50.9
51.3
51.4
52.1
50.8
55.4
55.2
58.3
53.4
75.8
46.4
44.8
45.3
47.9
44.1
52.1
53.2
54.7
51.8
52.3
52.2
53.8
51.9
52.5
52.3
53.6
51.3
57.1
57.3
59.6
55.2
77.2
48.7
46.6
47.4
49.6
45.2
54.4
55.1
56.2
52.3
53.1
52.9
54.4
52.6
53.8
54.1
55.2
52.4
59.1
58.3
60.8
57.1
78.3
49.9
47.8
48.8
50.4
46.8
55.3
56.8
57.3
54.1
54.7
54.0
55.9
54.2
54.2
55.1
57.3
53.2
59.9
59.4
62.3
57.8
81.9
46.2
43.4
44.8
47.4
41.2
52.2
52.1
54.2
51.8
49.9
50.1
51.9
49.4
50.9
51.2
53.1
50.2
56.4
55.2
57.3
53.1
74.1
48.4
45.6
46.2
49.2
41.9
53.6
53.4
56.0
53.4
50.8
51.2
53.3
50.2
52.4
53.4
55.2
51.8
57.9
56.3
58.2
53.4
76.4
49.6
46.2
47.9
50.6
42.3
54.1
54.7
57.3
54.2
52.3
53.6
54.0
51.8
53.6
53.7
56.8
52.3
58.1
57.4
59.4
54.8
79.6
50.3
47.9
49.4
51.9
43.7
55.8
56.4
58.4
54.9
53.6
54.3
55.2
53.5
54.2
55.8
58.3
54.9
58.9
58.2
59.8
56.9
83.3
HQ
Co(LI)(Q) H2O
Ni(LI)(Q)H2O
Cu(LI)(Q)H2O
Zn(LI)(Q)H2O
Co(LII)(Q) H2O
Ni(LII)(Q)H2O
Cu(LII)(Q)H2O
Zn(LII)(Q)H2O
Co(LIII)(Q) H2O
Ni(LIII)(Q)H2O
Cu(LIII)(Q)H2O
Zn(LIII)(Q)H2O
Co(LIV)(Q) H2O
Ni(LIV)(Q)H2O
Cu(LIV)(Q)H2O
Zn(LIV)(Q)H2O
Fluconazole
9
10
11
12
13
14
15
16
17
18
19
20
21
22
50.2
51.1
52.2
55.6
53.1
76.2
Coordination of both ligands i.e Schiff base ligands (HL) and het-
erocyclic base (HQ) was further confirmed by appearance of weak
Table 8
Minimum inhibitory concentration of isatin monohydrazone Schiff base ligands, 8-
hydroxyquinoline and their mixed ligand transition metal(II) complexes against
bacteria.
bands around 496–510 cmꢃ1 and 540–580 cmꢃ1 due to
m
(MAO)
(MAN) [17] stretching frequencies. Broad band in the region
between 3390 and 3440 cmꢃ1 was attributed due to asymmetric
and
m
Sr. No Compounds
MIC (
Gram+ve
B. subtilis M. Luteus P.aeruginosa P.
mendocina
lg/mL)
and symmetric
m(OAH) stretching modes of coordinated water
Gram–ve
molecule and weak band in the range 1555–1570 cmꢃ1 due to
HAOAH bending vibrations [18].
1
2
3
4
HLI
HLII
HLIII
HLIV
50
100
100
50
50
50
50
25
50
100
25
50
50
50
1H NMR and 13C NMR spectra
50
25
The 1H and 13C NMR spectra of Schiff base ligands HLI–IV, HQ and
their zinc(II) complexes are given in Tables 2 and 3. In 1H NMR of
Zn(II) complexes, the absence of AOH proton signal at d 13.38–
13.95 in Schiff base ligands HLI–IV was observed and hydroxyl
group proton at d 12.92 in HQ also showed deprotonation when
attached to zinc metal ion. With complexation deshielding was
observed in the proton of ACH from d 10.95–11.26 to d 11.15–
11.45 and not so much variation was observed in chemical shift
of aromatic protons of isatin ring and quinoline ring. The presence
of water molecule in complexes was confirmed by the appearance
of new signal around d 3.90 due to coordinated H2O proton [19].
In 13C NMR of complexes, shifting of signals of ketimine carbon
atom (C3) of Schiff base ligands HLI–IV from d 164.53–164.97 to d
167.08–165.84, CH aldimine carbon atom from d 161.93–162.31
to d 162.06–164.40 and (C2) carbonyl group of ligands from d
159.05 to d 160.72–162.04 were observed. Shifting of signal of car-
bon attached to hydroxyl group of quinoline ring was observed
along with small shift in C@N but no so much variation was
observed for other carbon atom signals.
5
6
7
8
HQ
100
25
12.5
6.25
25
25
25
12.5
50
12.5
25
12.5
12.5
12.5
50
12.5
25
12.5
50
12.5
12.5
25
25
25
12.5
12.5
25
50
25
12.5
6.25
25
12.5
50
25
25
25
25
25
50
25
12.5
12.5
6.25
<3.12
100
25
12.5
Co(LI)(Q) H2O
Ni(LI)(Q)H2O
Cu(LI)(Q)H2O
Zn(LI)(Q)H2O
Co(LII)(Q) H2O
Ni(LII)(Q)H2O
Cu(LII)(Q)H2O
Zn(LII)(Q)H2O
Co(LIII)(Q) H2O
Ni(LIII)(Q)H2O
Cu(LIII)(Q)H2O
Zn(LIII)(Q)H2O
Co(LIV)(Q) H2O
Ni(LIV)(Q)H2O
Cu(LIV)(Q)H2O
Zn(LIV)(Q)H2O
Streptomycin
12.5
12.5
25
12.5
12.5
12.5
12.5
12.5
25
25
12.5
12.5
3.12
3.12
9
10
11
12
13
14
15
16
17
18
19
20
21
22
25
12.5
6.25
12.5
6.25
6.25
12.5
<3.12
<3.12
<3.12
Electronic spectra and magnetic susceptibility measurements
The geometry of mixed ligand transition metal complexes were
obtained from the electronic spectral data and magnetic suscepti-
bility measurements. The electronic absorption spectra of all the
complexes were recorded in DMF (Table 4). Mixed ligand complexes
of Co(II) exhibited distinct absorption bands in the region of
ꢄ8800 cmꢃ1, 17,000 cmꢃ1 and 24,500 cmꢃ1 due to 4T1g(F) ? 4T2g(F)
Mass spectra
The LC-MS of Schiff base ligands HLI–IV, ligand HQ and their
complexes were recorded which were in close agreement with
molecular ion peaks. The mass spectra of HLI (C19H13N3O2) showed
molecular ion peak at m/z 316.2 and its corresponding copper com-
plex Cu(LI)(Q)ꢁH2O showed molecular ion peak at m/z 539.2 which
were in close agreement with molecular weights of compounds.
(m
1), 4T1g(F) ? 4A2g(F) (
The (
weak intensity. The ligand field parameters B, b were calculated
m
2) and 4T1g(F) ? 4T1g(P) (
m
3) transition [20].
m
2) band involving two electron transition was observed of

J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
717
Table 9
to three unpaired electrons showing octahedral geometry. Ni(II)
mixed ligand complexes showed absorption bands in the region of
Minimum inhibitory concentration of isatin monohydrazone Schiff base ligands,
8-hydroxyquinolineandtheirmixedligand transitionmetal(II) complexesagainst fungi.
3
9800 cmꢃ1, 15,000 cmꢃ1 and 24,000 cmꢃ1 due to A2g(F) ? 3T2g(F)
3
3
(m
1), A2g(F) ? 3T1g(F)
(m
2), A2g(F) ? 3T1g(P)
(m3)
transitions,
Sr. No
Compounds
MIC (lg/mL)
respectively and value of m2/m1 was found to 1.56–1.57, which was
V. dahliae
C. herbarium
T. soudanense
in accordance with octahedral geometry around nickel ion [21].
The Racah interelectronic repulsion parameters B, b calculated for
the Ni(II) complexes were found to be 678–729 cmꢃ1 and 0.65–
0.70, respectively. The B value was less than the free ion value
because of the decreased interelectronic repulsion from electron
delocalization [22]. Ni(II) complexes have magnetic moment of
3.01–3.08 BM, expected for S = 1 due to two unpaired electrons with
small contribution of orbital motion indicative of an octahedral
geometry. Copper(II) mixed ligand complexes showed bands in
the vicinity of 24,000 cmꢃ1 due to symmetry forbidden ligand ?
metal charge transfer and broad absorption band was observed in
the region of 15,000 cmꢃ1 due to 2Eg ? 2Tg transition. Broadness
of this band showed its distortion from octahedral geometry [23]
with magnetic moment 1.75–1.92 BM which was close to spin
allowed values expected for an S = 1/2 system indicative of an octa-
hedral geometry and broadness of band showed distortion from
octahedral geometry. Zinc(II) complexes showed absorption bands
in the region of 23,000 cmꢃ1 due to ligand to metal charge transfer
with zero magnetic moment which corresponds to all paired
electrons.
1
2
3
4
5
6
7
8
HLI
HLII
HLIII
HLIV
50
50
100
25
50
25
12.5
12.5
25
25
12.5
25
50
100
50
100
100
100
25
100
25
25
12.5
25
12.5
25
12.5
12.5
25
25
25
50
12.5
12.5
6.25
25
50
HQ
100
12.5
12.5
25
50
25
12.5
12.5
50
12.5
6.25
25
25
12.5
25
Co(LI)(Q) H2O
Ni(LI)(Q)H2O
Cu(LI)(Q)H2O
Zn(LI)(Q)H2O
Co(LII)(Q) H2O
Ni(LII)(Q)H2O
Cu(LII)(Q)H2O
Zn(LII)(Q)H2O
Co(LIII)(Q) H2O
Ni(LIII)(Q)H2O
Cu(LIII)(Q)H2O
Zn(LIII)(Q)H2O
Co(LIV)(Q) H2O
Ni(LIV)(Q)H2O
Cu(LIV)(Q)H2O
Zn(LIV)(Q)H2O
Fluconazole
9
10
11
12
13
14
15
16
17
18
19
20
21
22
25
12.5
12.5
12.5
25
25
12.5
6.25
12.5
<3.12
3.12
12.5
<3.12
<3.12
using band fitting equation for the Co(II) complexes and found to be
602–623 cmꢃ1 and 0.62–0.64, respectively, these parameters along
with the transition indicated d7 high spin system and characteristics
ESR of copper(II) complexes
of octahedral geometry around metal ion. The value of m2/m1 was
found to be around 1.92–1.94 with magnetic moment in the range
of 4.21–4.43 BM, which was in close agreement with S = 3/2 due
The spin hamiltonian parameters and G value of all Cu(II) com-
plexes were calculated by ESR spectra of complexes (Table 5). The
observed values for Cu(II) complex Cu(LI)(Q)ꢁH2O (Fig. 1) have
Fig. 3. Average Antibacterial activity data of ligands and their transition metal(II) complexes (1–22 as in Table 6).

718
J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
g\ = 2.09 and g|| = 2.31. In ESR spectrum, g tensor parameters with
g|| > g > 2.0023 for copper complex is in accordance with axially
elongated octahedral geometry and showed that the unpaired
XRD of Complexes
X-ray powder diffraction in the range 10 < 2h < 100 of Co(II)
complexes was carried out in order to give insight about dynamics
of compounds. X-ray diffraction study of Co(LI)(Q)H2O complex
indicated their amorphous nature (Fig. 2).
electron is in dx2
orbital of Cu(II) ion. The anisotropic G factor
ꢃy2
calculated from G = (g|| ꢃ 2.0023)/(g\ ꢃ 2.0023) was found to be
less than 4 and showed little exchange interaction between cop-
per(II) centers in solid state. This hyperfine interaction observed
for complexes was attributed due to interaction with nitrogen
and oxygen nuclei adjacent to copper ion [24]. The spin orbital cou-
pling constant k (ꢃ619 cmꢃ1) was calculated using the relation
gav = 2 (1–2k/10Dq), gav = 1/3(g|| + 2 g\) which is less than Cu(II) k
(ꢃ832 cmꢃ1) for free ion complex and supported the covalent char-
acter of M–L bond in complex. The molecular orbital coefficients,
Antimicrobial activity of ligands and their metal complexes
The antimicrobial activity of Schiff base ligands HLI–IV, ligand
HQ and their transition metal(II) complexes (M(LI–IV)(Q)H2O) were
tested against Gram positive bacteria (B. subtilis, M. luteus) and
Gram negative bacteria (P. aeruginosa, P. mendocina) and antifungal
activity was assessed against three fungi (V. dahlia, C. herbarium, T.
soudanense) using agar plate disc diffusion method at different
in-plane
p r bonding (a
bonding (b2) and in-plane 2) are usually
taken as measure of covalency of bonding were calculated. The
observed value of covalency parameter a2 (0.67) indicated that
the complex has some covalent character in ligand environment.
From these values of a2 and b2 (0.91), it was evident that there is
concentrations (25 lg/mL, 50 lg/mL, 100 lg/mL and 200 lg/mL)
in DMSO which was used as negative control and activities com-
pared with standard antibiotics Streptomycin and Fluconazole for
antibacterial and antifungal activity, respectively which were used
as positive controls. The zone of inhibition, percent mycelial
growth inhibition and their MIC values against the growth of
microorganisms for the compounds are summarized in Tables 6-
9 and their graphical representations are given in Figs. 3 and 4.
All synthesized compounds showed biological activity. Ligands
showed zone of inhibition in the range of 8–14 mm against gram
positive and gram negative bacteria. It has been observed that
the transition metal complexes showed enhancement in zone of
inhibition against bacterial strains ranging from 11 to 24 mm and
an interaction in in-plane
bonding (b2) is almost ionic. Lower value of a2 showed in-plane
bonding is more covalent than in-plane bonding which was
r bonding (a p
2), where as in-plane
r
p
confirmed by orbital reduction parameters i:e K|| (0.96) and K\
(1.09) calculated from these equations:
K
K
¼ ðgk ꢃ 2:0023Þ d ꢃ d transition=8k
k
¼ ðg? ꢃ 2:0023Þ d ꢃ d transition=2k
?
For these copper complexes, the observed value of K\ was
greater than K|| and it showed greater presence of significant
in-plane bonding [25].
MIC values ranging from 3.12 to 50
was revealed that copper(II) mixed ligand complex Cu(LIV)(Q)H2O
lg/mL. From biocidal data, it
p
Fig. 4. Average antifungal activity data of ligands and their transition metal(II) complexes (1–22 as in Table 7).

J. Devi, N. Batra / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 135 (2015) 710–719
719
showed maximum zone of inhibition 24 mm against growth of P.
medocina with MIC of 3.12 g/mL.
In case of antifungal activity, all the synthesized compounds
showed activity against fungal strains. Ligands showed mycelial
growth inhibition from 43.9% to 51.5% against various fungi, with
complexation to transition metal ion, it increased from 49.3% to
compared to the parent ligands under identical experimental con-
ditions. Among all compounds, Cu(LIV)(Q)H2O was found to be
most potent antimicrobial agent and may be used in food and
pharmaceutical industry after testing its toxicity in human beings.
l
Appendix A. Supplementary material
62.3% with MIC value ranging from 3.12 to 50
lg/mL. Similar to
antibacterial activity, copper(II) mixed ligand complex Cu(LIV
(Q)H2O showed higher mycelial growth inhibition against
C. herbarium and showed more than 60% mycelial growth inhibi-
)
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.saa.2014.07.041.
tion with MIC of 3.12 lg/mL.
References
This enhancement in biological activity on complexation is
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complexes exhibited moderate activity when compared with stan-
dard drugs and copper(II) complexes showed maximum activity.
The growth of trend of inhibition followed the order:
Cu > Ni ꢄ Co > Zn > HLI–IV > HQ.
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Based on the various observations of elemental analysis, molar
conductivity, spectroscopic techniques (IR, 1HNMR, 13C NMR, mass
and ESR) and magnetic susceptibility measurements, it was
observed that Schiff base ligands HLI–IV existed as monobasic tri-
dentate ONO bonded to metal ion through oxygen of carbonyl
group, azomethine nitrogen, deprotonated hydroxyl oxygen and
HQ ligand existed as monobasic bidentate ON bonded through oxy-
gen of hydroxyl group and nitrogen of quinoline ring. Mononuclear
structure with octahedral or distorted octahedral geometry has
been proposed for complexes. All the synthesized compounds
showed promising antimicrobial activities against various
microorganisms and their complexes showed better activity as
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