Dicoumarol complexes of Cu(II) based on 1,10-phenanthroline: Synthesis, X-ray diffraction studies, thermal behavior and biological evaluation

Article abstract of DOI:10.1016/j.saa.2012.09.096

A series of Cu(II) complexes containing dicoumarol derivatives and 1, 10-phenanthroline have been synthesized. Structural and spectroscopic properties of ligands were studied on the basis of mass spectra, NMR (¹H and ¹³C) spectra, FT-IR spectrophotometry and elemental analysis, while physico-chemical, spectroscopic and thermal properties of mixed ligand complexes have been studied on the basis of infrared spectra, mass spectra, electronic spectra, powder X-ray diffraction, elemental analysis and thermogravimetric analysis. X-ray diffraction study suggested the suitable octahedral geometry for hexa-coordinated state. The kinetic parameters such as order of reaction (n), energy of activation (E_a), entropy (S), pre-exponential factor (A), enthalpy (H) and Gibbs free energy (G) have been calculated using Freeman-Carroll method. Ferric-reducing antioxidant power (FRAP) of all complexes were measured. All the compounds were screened for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes and Bacillus subtilis, while antifungal activity against Candida albicans and Aspergillus niger have been carried out. Also compounds against Mycobacterium tuberculosis shows clear enhancement in the anti-tubercular activity upon copper complexation.

Full text of DOI:10.1016/j.saa.2012.09.096

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
Contents lists available at SciVerse ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Dicoumarol complexes of Cu(II) based on 1,10-phenanthroline: Synthesis,
X-ray diffraction studies, thermal behavior and biological evaluation
⇑
Hitesh R. Dholariya, Ketan S. Patel, Jiten C. Patel, Kanuprasad D. Patel
V.P. & R.P.T.P. Science College, Sardar Patel University, Vallabh Vidyanagar 388 120, Gujarat, India
g r a p h i c a l a b s t r a c t
h i g h l i g h t s
"
Mixed-ligand Cu(II) complexes
based on dicoumarol with 1,10-
phenanthroline.
"
Octahedral geometry was confirmed
using electronic spectra, X-ray
diffraction studies and magnetic
measurement.
"
"
Measurements of kinetic parameters
using Freeman–Carroll method.
Antioxidant, anti-tubercular and
antimicrobial studies of complexes.
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 29 June 2012
Received in revised form 30 August 2012
Accepted 8 September 2012
Available online 12 October 2012
A series of Cu(II) complexes containing dicoumarol derivatives and 1, 10-phenanthroline have been syn-
thesized. Structural and spectroscopic properties of ligands were studied on the basis of mass spectra,
NMR (1H and 13C) spectra, FT-IR spectrophotometry and elemental analysis, while physico-chemical,
spectroscopic and thermal properties of mixed ligand complexes have been studied on the basis of
infrared spectra, mass spectra, electronic spectra, powder X-ray diffraction, elemental analysis and ther-
mogravimetric analysis. X-ray diffraction study suggested the suitable octahedral geometry for hexa-
coordinated state. The kinetic parameters such as order of reaction (n), energy of activation (Ea), entropy
(Sꢀ), pre-exponential factor (A), enthalpy (Hꢀ) and Gibbs free energy (Gꢀ) have been calculated using Free-
man–Carroll method. Ferric-reducing antioxidant power (FRAP) of all complexes were measured. All the
compounds were screened for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa,
Streptococcus pyogenes and Bacillus subtilis, while antifungal activity against Candida albicans and Asper-
gillus niger have been carried out. Also compounds against Mycobacterium tuberculosis shows clear
enhancement in the anti-tubercular activity upon copper complexation.
Keywords:
Dicoumarol derivative
1, 10-Phenanthroline
X-ray diffraction study
Antimicrobial
Antioxidant
Anti-tubercular
Ó 2012 Elsevier B.V. All rights reserved.
Introduction
They are also extensively used as analytical reagents [1,2]. The
antitumor activities of coumarin and its known metabolite couma-
4-Hydroxycoumarin derivatives have a lot of applications as
drugs with several type of pharmacological agents possessing anti-
coagulant, spasmolytic, bacteriostatic, potential anti-HIV, anti-
fungal and herbicides activity among others. Some coumarin
derivatives are known for their in vitro antibiotic and antifungal
activities, furthermore some of the investigated compounds show
low toxicity and dose dependent anticoagulant activity in vivo.
rin derivatives were tested in several human tumor cell lines by
Steffen et al. [3]. Many coumarin derivatives have been well-
known from natural sources, especially green plants. The very long
association of plant coumarins with various animal species and
other organisms throughout progress may account for the
surprising range of biochemical and pharmacological activities.
Coumarins have important effects as enzyme inhibitors [4–6] and
they are precursors of toxic substances. In addition, these com-
pounds are involved in the actions of plant growth hormones
and growth regulators, Control of respiration, photosynthesis and
defense against infection. The coumarins have been recognized to
⇑
Corresponding author. Tel.: +91 2692 230011; fax: +91 2692 235207.
E-mail addresses: hitesh.msc123@gmail.com (H.R. Dholariya), drkdpatel64@
yahoo.co.in (K.D. Patel).
1386-1425/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.saa.2012.09.096

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H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
possess anti-inflammatory, antioxidant, antiallergic, hepatoprotec-
tive, antithrombotic, antiviral and anticarcinogenic activities [7].
Recently, an area of coumarin chemistry is increasing that concerns
important biologically active metal complexes of coumarin-based
ligands. In general, coordination of metal ions to therapeutic
agents improves their efficacy and accelerates bioactivity. In this
context, a broad array of medicinal applications of metal com-
plexes has been investigated [8–13].
PerkinElmer, USA. The analysis carried out under a nitrogen atmo-
sphere at a heating rate of 20 °C/min from 30 °C to 840 °C. Effective
magnetic susceptibility measurement were calculated by the
Gouy’s method using mercury tetrathiocyanato cobaltate (II) as a
calibrant (
v
= 16.44 ꢂ 10ꢁ6 c.g.s. units at 20 °C). Molar susceptibil-
ity was corrected using Pascal’s constant [29].
Crystallographic analysis
1,10-Phenanthroline(Ph) is well-known chelating bidentate li-
gand for transition metal ions which played an important role in
many fields such as coordination chemistry [14,15], in agreement
with the electron-deficient characteristics of the hetero aromatic
X-ray diffraction intensities were carried out with 0.0025
accuracy using XRD Diffractometer (powder), Xpert MPD, Philips,
Holland equipped with 2 kW power and Cu target X-ray tube used
as a source of wavelength 1.542 Å, while the data were accumulate
using JCPDF database. The detector used in the system was Xe-
filled counterate and 2° h measurement range of the instrument
is 3–136°. The system contains goniometer was operated on verti-
cal and horizontal mode with h–h and h–2h position respectively
with radius 130–230 mm.
rings and to the consequent lower
r-donor ability of its nitrogen
atoms [16], in spite of the low -donor ability of the hetero aro-
r
matic nitrogen atoms, the stability of these complexes is somewhat
higher mainly due to the hydrophobic nature of Ph and to the con-
sequent larger desolvation of metal cations upon complex forma-
tion [17,18]. In recent years, the study of CuAPh complexes has
become progressively more important due to their antimicrobial
and antioxidant properties [19–21].
Preparation of ligands
In our previous reports, we have mentioned a series of couma-
rin derivatives and its transition metal complexes [22–25]. Herein
we report the synthesis, antimicrobial, antioxidation and anti-
tubercular activities of Cu(II) mixed ligand complexes using
1,10-phenanthrolin with coumarin derivatives. We describe here
characterization, powder X-ray diffraction study and spectroscopic
features of new mixed ligand Cu(II) complexes. The thermal behav-
ior of these complexes has been investigated by using thermo-
4-Hydroxy-6-methyl-2H-chromen-2-one: 6-methyl-4-hydroxy-
coumarin was synthesized as reported method [30].
Synthesis of ligands (HL1–HL6)
General procedure for synthesis of the ligands (HL) is shown in
Scheme 1. The ligands were characterized using elemental analy-
sis, FT-IR, Mass spectra and NMR (1H and 13C) spectroscopy.
gravimetric (TG) analysis. Thermogravimetry is
a process in
which a substance is decomposed in the presence of heat, which
causes bonds of the molecules to be broken [26,27]. Kinetic param-
eters like order of reaction (n), activation energy (Ea), entropy
change (Sꢀ), enthalpy change (Hꢀ), free energy change (Gꢀ) and
pre-exponential factor (A) are measured out using kinetic studies
of thermal decomposition reactions.
3, 30-(Phenylmethylene)bis(4-hydroxy-6-methyl-2H-chromen-2-one-
(HL1)
An ethanolic solution (25 mL) of 6-methyl-4-hydroxycoumarin
(0.02 mol) was heated in water bath for 2 h, to obtain a clear solu-
tion. Ethanolic solution of benzaldehyde (0.01 mol) (25 mL) was
added in reaction mass and refluxed in presence of catalytic
amount of H2SO4 for 18 h. and the progress of the reaction was
monitored by TLC using mobile phase Ethyl acetate:Haxane (6:4).
After the completion of reaction, the reaction mixture was cooled
to room temperature. The product obtained was separated out
and were recrystallized from ethanol. Yield, 65%; m.p. 235 °C. Anal.
Calcd. for C27H20O6: C, 73.41, H, 4.79. calculated: C, 73.63, H, 4.58;
Experimental
Materials, instruments and methods
Chemicals were purchased from the following commercial
sources: Spectrochem Pvt. Ltd., Mumbai, E. Merck Pvt. Ltd., Mum-
bai, s.d. fine-chem Ltd., Mumbai and used as received. All solvents
of analytical grade were distilled, purified and dried using appro-
priate methods [28]. All reactions were monitored by thin-layer
chromatography (TLC on aluminium plates coated with silica gel
60 F254, 0.25 mm thickness, Merck) and detection of the compo-
nents were carried out under UV light or explored in iodine cham-
ber. The metal nitrates were used in hydrated form. Elemental
analysis was performed on elemental analyzer PerkinElmer, USA
2400-II CHN. Analyses of metal ions were carried out by the disso-
lution of the solid complexes in hot concentrated nitric acid, fur-
ther diluting with distilled water and filtered to remove the
precipitated organic ligands. Remaining solution was neutralized
with ammonia solution and the metal ions were titrated against
EDTA. Melting points were measured using open capillary. Infrared
spectra were recorded in the region of 4000–400 cmꢁ1 on Shima-
dzu FTIR 8401 spectrophotometer. All infrared spectra were run
as potassium bromide pellets. 1H and 13C NMR measurements
were carried out on Advance-II 400 MHz Bruker NMR spectrome-
ter. Chemical shifts were measured with respect to TMS as internal
standard and DMSO-d6 used as solvent. The Mass spectra were re-
corded on Thermo Scientific, USA. Electronic spectra were recorded
on a LAMBDA 19 UV/VIS/NIR in the region of 200–1200 nm.
Thermogravimetric scans were run on a model Diamond TG/DTA,
FT-IR (KBr cmꢁ1): 3180, 3050
cmꢁ1, 1623, 1574 (C@C) cmꢁ1, 1179, 1125, 1089, 820, 790, 744
(CAO) cmꢁ1, 2923(asym), 2738(sym) (CH3) cmꢁ1, 1436(asym),
1356(sym) d(CH3) cmꢁ1 1H NMR (DMSO-d6 400 MHz): d: 2.376
m m(C@O)
(AOH/H2O) cmꢁ1, 1663
m
m
m
.
(6H, s, ACH3), 6.485 (1H, Aliphatic), 7.167–7.873 (11H, m, Aromatic
proton), 10.156 (AOH phenolic); 13C NMR (DMSO-d6 100 MHz): d:
21.30 (C-24, 25), 35.67 (C-9), 103.54 (C-3, 18), 115.57, 117.22,
123.91, 127.08, 127.83, 128.35,132.19, 132.65, 141.24 (8C, Ar–C),
150.43 (C-8a, 23a), 164.67 (C-2, 17), 165.55 (C-4, 19); ESI-MS (m/
z): 440.7.
3, 30-((3-Hydroxyphenyl)methylene)bis(4-hydroxy-6-methyl-2H-
chromen-2-one(HL2)
HL2 was synthesized by the same method used for HL1 by using
3-hydroxybenzaldehyde as a substitute of benzaldehyde. Yield,
72%; m.p. 214 °C. Anal. Calcd. for C27H20O7: C, 71.24, H, 4.20. calcu-
lated: C, 71.05, H, 4.42; FT-IR (KBr cmꢁ1): 3135, 3054
m
(AOH/H2O)
(C@C) cmꢁ1, 1152, 1125,
(CAO) cmꢁ1, 2926(asym), 2861(sym)
(CH3)
cmꢁ1, 1449(asym), 1354(sym) d(CH3) cmꢁ1 1H NMR (DMSO-d6
cmꢁ1, 1666
m m
(C@O) cmꢁ1, 1624,1576
1094, 819, 792, 776
m
m
.
400 MHz): d: 2.365 (6H, s, ACH3), 6.267 (1H, Aliphatic), 6.519–
7.701 (10H, m, Aromatic proton), 9.231, 10.253 (AOH phenolic);
13C NMR (DMSO-d6 100 MHz): d: 21.55 (C-24, 25), 35.79 (C-9),
103.96 (C-3, 18), 112.50 , 113.53, 115.67, 117.32, 117.63, 123.55,

H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
321
Scheme 1. General procedure for synthesis of ligands (HL).
128.88, 132.63, 132.86, 141.47 (10C, Ar–C), 150.28 (C-8a, 23a),
157.17 (C-12), 164.95 (C-2, 17), 165.34 (C-4, 19); ESI-MS (m/z):
456.4.
m.p. 282 °C. Anal. Calcd. for C27H19NO8: C, 66.78, H, 4.12, N, 2.67.
calculated: C, 66.80, H, 3.95, N, 2.89; FT-IR (KBr cmꢁ1): 3140,
3025
cmꢁ1, 1150, 1122, 1088, 815, 785, 735
2756(sym)
(CH3) cmꢁ1, 1442(asym), 1340(sym) d(CH3) cmꢁ1
m
(AOH/H2O) cmꢁ1, 1664
m
(C@O) cmꢁ1, 1621 ,1573
m
(C@C)
(CAO) cmꢁ1, 2920(asym),
1H
m
3, 30-((4-Hydroxyphenyl)methylene)bis(4-hydroxy-6-methyl-2H-
chromen-2-one(HL3)
m
.
NMR (DMSO-d6 400 MHz): d: 2.382 (6H, s, ACH3), 6.353 (1H, Ali-
phatic), 7.128–8.234 (10H, m, Aromatic proton), 10.412 (AOH phe-
nolic); 13C NMR (DMSO-d6 100 MHz): d: 21.73 (C-24, 25), 35.82 (C-
9), 103.58 (C-3, 18), 115.39, 117.65, 121.43, 123.21, 128.37, 132.
51, 132.90, 136.23, 141.48 (9C, Ar–C), 150.64 (C-8a, 23a), 164.80
(C-2, 17), 165.55 (C-4, 19); ESI-MS (m/z): 485.2.
HL3 was synthesized by the same method used for HL1 by using
4-hydroxybenzaldehyde as a substitute of benzaldehyde. Yield,
68%; m.p. 221 °C. Anal. Calcd. for C27H20O7: C, 71.32, H, 4.63. calcu-
lated: C, 71.05, H, 4.42; FT-IR (KBr cmꢁ1): 3170,3045
m
(AOH/H2O)
(C@C) cmꢁ1, 1165, 1123,
(CAO) cmꢁ1, 2924(asym), 2840(sym)
(CH3)
cmꢁ1, 1438(asym), 1352(sym) d(CH3) cmꢁ1 1H NMR (DMSO-d6
cmꢁ1, 1665
m m
(C@O) cmꢁ1, 1623,1575
1087, 815, 787, 745
m
m
3, 30-((2-Nitrophenyl)methylene)bis(4-hydroxy-6-methyl-2H-
chromen-2-one(HL6)
.
400 MHz): d: 2.364 (6H, s, ACH3), 6.405 (1H, Aliphatic), 7.113–
7.815 (10H, m, Aromatic proton), 9.311, 10.156 (AOH phenolic);
13C NMR (DMSO-d6 100 MHz): d: 21.30 (C-24, 25), 35.67 (C-9),
103.54 (C-3, 18), 112.32 , 115.87, 117.82, 123.48, 128.36, 132.23,
132.92, 134.15, (8C, Ar–C), 150.46 (C-8a, 23a), 158.75 (C-13),
164.52 (C-2, 17), 165.44 (C-4, 19); ESI-MS (m/z): 456.8.
HL6 was synthesized by the same method used for HL1 by using
2-nitrobenzaldehyde as a substitute of benzaldehyde. Yield, 62%;
m.p. 275 °C. Anal. Calcd. for C27H19NO8: C, 66.91, H, 4.24, N, 2.74.
calculated: C, 66.80, H, 3.95, N, 2.89; FT-IR (KBr cmꢁ1):
3150.3035
(C@C) cmꢁ1, 1162, 1120, 1079, 817, 787, 740
2923(asym), 2746(sym)
(CH3) cmꢁ1, 1437(asym), 1350(sym)
d(CH3) cmꢁ1 1H NMR (DMSO-d6 400 MHz): d: 2.360 (6H, s,
m
(m, AOH/H2O) cmꢁ1, 1660
m
(C@O) cmꢁ1, 1623, 1574
(CAO) cmꢁ1
m
m
,
3, 30-((4-Chlorophenyl)methylene)bis(4-hydroxy-6-methyl-2H-
chromen-2-one(HL4)
m
.
ACH3), 6.377 (1H, Aliphatic), 7.184–8.364 (10H, m, Aromatic pro-
ton), 10.630 (AOH phenolic); 13C NMR (DMSO-d6 100 MHz): d:
21.47 (C-24, 25), 35.37 (C-9), 103.25 (C-3, 18), 116.40, 117.26,
123.36, 123.85, 128.57, 131. 05, 132.14, 132.62, 132.93, 141.28,
148.11 (11C, Ar–C), 150.32 (C-8a, 23a), 164.63 (C-2, 17), 165.72
(C-4, 19); ESI-MS (m/z): 485.8.
HL4 was synthesized by the same method used for HL1 by using
4-chlorobenzaldehyde as a substitute of benzaldehyde. Yield, 70%;
m.p. 265 °C. Anal. Calcd. for C27H19ClO6: C, 68.48, H, 4.24. calcu-
lated: C, 68.29, H, 4.03; FT-IR (KBr cmꢁ1): 3195,3052
m
(AOH/
(C@C) cmꢁ1, 1201,
(CAO) cmꢁ1, 2926(asym), 2731(sym)
1440(asym), 1346(sym) d(CH3) cmꢁ1 1H NMR
H2O) cmꢁ1, 1661
1124, 1086, 816, 786, 711
(CH3) cmꢁ1
m m
(C@O) cmꢁ1, 1625,1574
m
m
,
.
(DMSO-d6 400 MHz): d: 2.366 (6H, s, ACH3), 6.389 (1H, Aliphatic),
7.171–8.142 (10H, m, Aromatic proton), 10.044 (AOH phenolic);
13C NMR (DMSO-d6 100 MHz): d: 21.35 (C-24, 25), 36.04 (C-9),
103.56 (C-3, 18), 115.25, 118.02, 122.12, 125.48, 128.63, 132. 07,
132.51, 135.02, 141.32 (9C, Ar–C), 150.14 (C-8a, 23a), 165.06 (C-
2, 17), 165.82 (C-4, 19); ESI-MS (m/z): 474.3, 476.4(M + H+).
Synthesis of metal complexes
All these complexes HPC1–HPC6 was synthesized according to
same procedure as HPC, their analytical and physiochemical
parameters are summarized in Table 1, while general synthetic
route of complexes (HPC) shown in Scheme 2.
The Dicoumarol derivatives (0.01 mol) was dissolved in water
(25 mL). To that aqueous solution of Cu(NO3)2ꢃ3H2O (0.01 mol,
25 mL) was gradually added, followed by ethanolic solution of
1,10-phenthroline (0.01 mol, 25 mL). The pH was adjusted to
4.5–6.0 with diluted NaOH solution. Further the mixture was
3, 30-((4-Nitrophenyl)methylene)bis(4-hydroxy-6-methyl-2H-
chromen-2-one(HL5)
HL5 was synthesized by the same method used for HL1 by using
4-nitrobenzaldehyde as a substitute of benzaldehyde. Yield, 66%;

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H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
heated under reflux for 3–5 h and then heated over a steam bath to
evaporate up to half of the volume. The reaction mixture was kept
overnight at room temperature. A fine amorphous powder was ob-
tained was filtered and dried in air. The physiological and analyti-
cal data of the synthesized complexes are listed in Table 1. The
complexes comprise high melting points (above 300 °C) and insol-
uble in common organic solvents and partially soluble in DMSO.
(c) 20 mM FeCl3ꢃ6H2O (MW 270.30) in distilled water (DW).
(d) 1 mM of ascorbic acid (MW 176.13 g/mol) dissolved in
100 mL DW.
FRAP working solution: Mix the above prepared (a–c) solutions
in the ratio of 10:1:1 respectively. A mixture of 40.0 lL, 0.5 mM
sample solution and 1.2 mL FRAP reagent was incubated at 37 °C
for 15 min. The working solution must be always freshly prepared.
The ascorbic acid was used as a standard antioxidant compound.
The absorbance of the reaction mixture was measured at 593 nm
Pharmacology
Antimicrobial assay
against a blank containing DMF (400 lL) instead of the sample.
Antimicrobial activities of the compounds were tested against
the following test microorganisms (all ATCC cultures were col-
lected from Bangalore and tested against above mentioned known
drugs): bacteria (Bacillus subtilis ATCC11774, Streptococcus pyogenes
ATCC12384, Escherichia coli ATCC25922, Pseudomonas aeruginosa
ATCC25619) and fungi (Candida albicans ATCC66027, Aspergillus ni-
ger ATCC64958), compared to standard drugs Ciprofloxacin and
Norfloxacin (antibacterial), Flucanazole and Nystatin (antifungal)
as standard drugs. Bioactivities of the compounds were carried
out using Kirby–Bauer disk diffusion method according to the
guidelines of Clinical and Laboratory Standards Institute (CLSI)
[31]. The Minimum inhibition concentration (MIC) screening data
are shown in Table 2. The standard solutions of antibacterial drugs
(Ciprofloxacin, Norfloxacin) and antifungal drugs (Flucanazole,
Nystatin) were prepared in DMSO. The calculated standard devia-
tion for any result was not more than 1.0 mm. In this method,
antibiotics are impregnated onto paper disks and then placed on
a seeded Mueller–Hinton agar plate using a mechanical dispenser
or sterile forceps. The plate is then incubated for 16–18 h at
37 °C and the diameter of the zone of inhibition around the disk
is measured to the nearest millimeter. The solution of all newly
synthesized compounds and standard drugs were prepared at
The antioxidant activities results were expressed as ascorbic equiv-
alent (mmol/100 g of dried compound).
The FRAP Value can be calculated by following equation:
Ascorbic acid concentrationðmM=100 g of sampleÞ
D
D
A593 nm of test sample standard ðmmÞ
¼
ꢂ
ꢂ 100
A593 nm of standard
sample ðmgÞ
In vitro evaluation of anti-tuberculosis activity
An anti-tuberculosis activity (MICs) of the title compounds
were determined and interpreted for Mycobacterium tuberculosis
H37Rv according to the procedure of approved micro-dilution
reference method of antimicrobial susceptibility testing
[33–35]. Compounds were taken at concentrations of 100, 50,
25, 12.5, 6.25 and 3.125
tration was used for the study. To this, 9.0 mL of Lowenstein–
Jensen medium was added. sweep from M. tuberculosis
lg/mL in DMSO, 1.0 mL of each concen-
A
H37Rv strain culture was discharged with the help of nichrome
wire loop with a 3 mm external diameter into a vial containing
4 mL of sterile distilled water. The vial was shaken for 5 min.
Then using nichrome wire loop suspension was inoculated on
the surface of each of Lowenstein–Jensen medium containing
the test compounds. Further test media was incubated for
28 days at 37 °C. Readings were seen after 28 days of incubation.
The appearance of turbidity was considered as bacterial growth
and indicates resistance to the compound. Test compounds were
compared to reference drugs Isoniazid, Ethambutol and Strepto-
mycin. Lowenstein–Jensen medium containing standard drugs
was inoculated with M. tuberculosis H37Rv strain. Anti-tubercular
activity test was run in triplicate and the deviation for any
triplicate results was not more than 1% to 5% and results are
summarized in (Table 3).
600, 400, 200, 100, 70, 40, 20
60, 40, 35, 30, 20, 15, 10, 5, 2, 1
l
l
g/mL concentrations, at 100, 80,
g/mL concentrations in the wells
of microplates by diluting in MHB, respectively. The lowest con-
centration of the compound that completely inhibits macroscopic
growth was determined and minimum inhibitory concentrations
(MICs) are reported in Table 2.
Method of antioxidant assay
Ferric reducing antioxidant power (FRAP) was measured by a
modified method [32]. The antioxidant potentials of the com-
pounds were estimated as their power to reduce the TPTZ–Fe(III)
complex to TPTZ–Fe(II) complex, The total antioxidant capacity of
biological samples, but we tried the FRAP assay, The method is
simple, fast and reproducible results can be obtained. The results
are expressed as ascorbic equivalent (mmol/100 g of dried
compound).
Results and discussion
Preparation of solution:
The properties of Cu(II) complexes with coumarin derivatives
were studied. The synthesized compounds were explained by ele-
mental analysis, infrared spectra, electronic spectra, mass spectros-
copy, X-ray diffraction study, thermal methods, magnetic and
kinetic measurements. Further antimicrobial, antioxidant and
anti-tuberculosis activities of same compounds were carried out.
(a) Acetate buffer, 300 mM pH 3.6 (3.1 g sodium acetate trihy-
drate and 16 mL conc. acetic acid per L of buffer solution).
(b) 10 mM 2,4,6-tripyridyl-s-triazine (TPTZ) (MW 312.34) in
40 mM HCl.
Table 1
Analytical and physiochemical parameters of synthesized compounds.
Compounds/empirical formula
Elemental analyses, % found (required)
m.p. (°C)
Yield (%)
Molecular mass
leff B.M.
C
H
N
Cu(II)
C
C
C
C
C
C
39H32CuN2O9/(HPC1)
39H34CuN2O11/(HPC2)
39H32CuN2O10/(HPC3)
39H31ClCuN2O9/(HPC4)
39H35CuN3O13/(HPC5)
39H33CuN3O12/(HPC6)
63.44(63.62)
60.63(60.81)
62.45(62.27)
60.57(60.78)
57.13(57.32)
58.40(58.61)
4.17(4.38)
4.22(4.45)
4.05(4.29)
4.20(4.05)
4.51(4.32)
3.94(4.16)
3.98(3.81)
3.86(3.64)
3.93(3.72)
3.82(3.63)
5.38(5.14)
5.47(5.26)
8.39(8.63)
8.03(8.25)
8.61(8.45)
8.01(8.25)
7.56(7.78)
7.73(7.95)
>350
>350
>350
>350
>350
>350
78
70
72
68
65
60
717.26
733.24
733.56
751.05
762.15
762.42
1.84
1.82
1.91
1.87
1.83
1.86

H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
323
Scheme 2. General synthetic route of complexes (HPC).
Table 2
Antimicrobial and antioxidant activities of compounds.
Entry
Antimicrobial activity (minimal inhibition concentration)
Gram negative bacteria Gram positive bacteria
Antioxidant activity
Fungus
FRAP value (mmol/100 g)
E. coli
P. aeruginosa
S. pyogenes
B. subtilis
C. albicans
A. niger
HL1
HL2
HL3
HL4
HL5
HL6
HPC1
HPC2
HPC3
HPC4
HPC5
HPC6
Ciprofloxacin
Norfloxacin
Flucanazole
Nystatin
Ascorbic acid
400
600
400
100
200
200
400
600
400
70
100
200
20
10
NT
400
100
100
100
200
400
200
100
100
100
100
200
10
100
70
40
70
70
100
40
20
20
40
70
70
20
10
NT
NT
NT
70
20
20
20
70
70
40
20
20
20
40
40
05
10
NT
NT
NT
200
200
200
100
200
200
200
200
100
100
200
200
NT
200
200
200
100
200
200
100
200
100
100
200
200
NT
NT
NT
NT
NT
NT
NT
354
405
438
402
397
377
NT
NT
NT
NT
–
10
NT
NT
NT
NT
10
100
NT
NT
10
100
NT
NT
NT
E. Coli = ATCC25922; P. aeruginosa = ATCC25619; S. pyogenes = ATCC12384; B. subtilis = ATCC11774; C. albicans = ATCC 66027; A. niger = ATCC 64958.
NT = Not tested.
Table 3
IR spectra
Anti-tuberculosis activity of compounds.
The important infrared spectral bands and their tentative
assignments for the synthesized compounds were recorded as KBr
disks and are summarized in Table 4. The IR data of free ligands
and its metal complexes were carried out within the IR range
4000–400 cmꢁ1. The IR spectra of the dicoumarol derivatives show
Entry
MIC
l
g/mL M. tuberculosis (MTCC 200)
% Inhibition
HL1
HL2
HL3
HL4
HL5
HL6
HPC1
HPC2
HPC3
HPC4
HPC5
HPC6
Streptomycin
Isoniazid
Ethambutol
50
12.5
50
12.5
50
100
25
3.125
25
12.5
25
35
36
18
82
64
32
53
92
40
90
87
68
98
99
99
weak bands at ꢅ3135 cmꢁ1
,
ꢅ3050 cmꢁ1 and ꢅ1330 cmꢁ1
,
ꢅ1310 cmꢁ1 corresponding to
m
(OAH) respectively [36,37]. On
complexation OAH peak has vanished indicates deprotonation of
OAH proton. The
m
(C@O) of lactone rings observed at ꢅ1665 cmꢁ1
in free ligand is shifted to lower frequencies (ꢅ15 cmꢁ1) due to
complex formation [38], and further supported by shifting of
50
m(CAC), m(CAO), and m(CAOAC) stretch frequencies to higher values
6.25
0.25
3.125
[39–41]. In IR spectrum of ligands and its complexes exhibited
characteristic absorption band at ꢅ2920 and at 2850–2700 cmꢁ1
(asym. & sym. str.) for
m
(CH3) cmꢁ1 and ꢅ1450 cmꢁ1 and ꢅ1345
for (asym. & sym. str. of d(CH3) cmꢁ1). Two bands at ꢅ1620 and
ꢅ1570 cmꢁ1 were assigned to stretching vibration of conjugate
double bonding in the free ligand [42]. The HAOAH bending mode
occurring about 1600 cmꢁ1 has not been observed because of the
presence of strong absorbing group like methine group (ACH@). It
is difficult to resolve both these bands [43]. A broad band at
Elemental analysis
Analytical and physicochemical data of the complexes are sum-
marized in Table 1. Complexes are colored and stable in air. They
are insoluble in water and in most organic solvents but partially
soluble in DMSO. The structure of the complexes is assumed
according to the chemical reaction as shown below;
ꢅ3430 cmꢁ1 observed in the complex was due to the
m (OH) charac-
teristic peak of a coordinated water molecule [44]. The IR spectrum
of the free ligand shows a very stronger bands at ꢅ1630 and
ꢅ1576 cmꢁ1 due to stretching frequency of C@N present in
1,10-phenanthroline moiety. These bands were shifted to lower fre-
quencies in the complexes ꢅ30 cmꢁ1, which clearly indicate that it
CuðNO Þ ꢃ 3H O þ HL þ Ph dil:NaOH½CuðHLÞðPhÞðH OÞðOHÞꢄ ꢃ XH O
ƒƒƒ!
3
2
2
2
2
þ 2NaNO3 þ XH2O
where HL = HL1, HL2, HL3, HL4, HL5, HL6 (X = 1, 2, 1, 1, 3, 2).

324
H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
Table 4
FT-IR data of synthesized compounds.
w
Complexes
(HPC1–HPC6)
m
(OH/H2O)
m
(C@N)
m
(C@O)
m
(C@C)
m
(CAC)
m
(CAO),
m
m
(CH3) cmꢁ1
d(CH3) cmꢁ1
m
(CuAN)w
m
(CuAO)w
cmꢁ1
cmꢁ1
cmꢁ1
cmꢁ1
(CAOAC) cmꢁ1
cmꢁ1
cmꢁ1
HPC1
HPC2
HPC3
HPC4
HPC5
HPC6
3430(br)
1542
1652
1610
1182.1143, 1120, 852,
815, 782
1189, 1147, 1121.849,
816, 781
1185, 1138, 1120, 834,
818, 779
1186, 1141, 1123, 839,
820, 783
1188, 1142, 1126, 830,
824, 786
1180, 1149, 1127, 836,
827, 781
2924(asy),
2862(sy)
2923(asy),
2860(sy)
2925(asy),
2858(sy)
2923(asy),
2861(sy)
2927(asy),
2858(sy)
2931(asy),
2869(sy)
1425(asy),
1343(sy)
1428(asy),
1345(sy)
1432(asy),
1340(sy)
1425(asy),
1345(sy)
1432(asy),
1352(sy)
1435(asy),
1360(sy)
465
565
3428(br)
3435(br)
3440(br)
3425(br)
3432(br)
1544
1540
1541
1545
1547
1655
1650
1647
1645
1653
1613
1607
1611
1612
1608
478
462
467
464
475
567
563
561
569
560
s = strong, w = weak, br = broad.
460—800 ꢆC
ƒƒƒƒƒƒ!
has been affected upon complexation via metal ions. In IR spectrum
all the complexes shows the bands at ꢅ549 and ꢅ460 cmꢁ1 due to
the CuAO and CuAN respectively. Mehmet et al. mentioned the
weak band around ꢅ550 cmꢁ1 and ꢅ468 cmꢁ1 were attributed to
the CuAO and CuAN stretching frequency [45–47].
CuðHL1Þꢄ
metal residueðCuOÞ þ HL1
Removal of HL1ligand molecules
The thermal decomposition occurs in three steps. In first step, endo-
thermic decomposition between 50 and 110 °C attributed to dehy-
dration process, which is due to loss of lattice water molecule. The
mass loss observed is 2.82%, which is nearly equal to calculated va-
lue 2.51%. The loss of lattice water molecules is a first order and the
value of the energy of activation for the dehydration process is
found to be 3.58 kJ molꢁ1. In the second step, endothermic decom-
position between 160 and 460 °C corresponds to loss of coordinated
water molecule, hydroxyl ion and 1,10-phenanthroline ligand. The
observed mass loss is 32.01%, which is nearly equal to calculated va-
lue 29.99%. Next step, exothermic decomposition between 460 and
800 °C corresponds to loss of coordinated HL1 ligand. The observed
mass loss is 38.59%.
Mass spectra
The mass spectra of the complex HPC1 (C39H32CuN2O9) reveals
that molecular ion peak at m/z 717 of complex (without water of
crystallization) along with several other peaks observed at 700,
682, 667, 652, 626, 574, 548, 471, 419, 367, 235, 207 and 117 m/
z value.
Thermal studies
First is dehydration process with endothermic effect on
DTG curve at 108 °C, while increasing in temperature of
[Cu(HL1)(Ph)(H2O)(OH)], which shows also endothermic effect at
290 °C respectively. Exothermic DTG peak at 487 °C associated
with elimination of HL1 ligand.
Each compound (HPC1–HPC6) has followed the decomposition
process as shown below;
Solid-1 heat Solid-2 þ Gas
ƒ!
In our investigation, thermal behaviors of the all complexes in
terms of stability, peak temperatures and values of kinetic param-
eters are calculated. Kinetic parameters of decomposition method
such as entropy (Sꢀ), enthalpy (Hꢀ), pre-exponential factor (A),
and Gibbs free energy of the decomposition (Gꢀ), were studied
using the Horowitz–Metzger equation method is discussed in brief
and the results obtained by these methods are well correlated with
each other and summarized in Table 6. The pre-exponential factor,
A, was calculated from the equation: Ea/RTs2 = A/U exp (ꢁEa/RTs).
The entropy (Sꢀ), enthalpy (Hꢀ), and Gibbs free energy, (Gꢀ),
were calculated from: Sꢀ = 2.303(log Ah/KTs) R, Hꢀ = Ea ꢁ RTsꢀ and
Gꢀ = Hꢀ ꢁ Ts Sꢀ respectively. Where h is the Plank constant, U is
the heating rate, K is the Boltzmann constant, and Ts is the temper-
ature of peak from DTG curve. According to the kinetic data
obtained from DTG curves, all the complexes have negative entro-
py, which indicates that the studied complexes have more ordered
systems [50]. The energy of activation (Ea) is helpful in assigning
the strength of the bonding of ligand moieties with the metal
ion. The relative high Ea value (Table 6) indicates that both the
ligands is strongly bonded to the metal ion [51].
This process comprises several stages. The method reported by
Freeman and Carroll [48] integral method of Coats and Redfern
[49], the approximation method of Horowitz and Metzger [49]
has been assumed. Plots of [
D log(dw/dt)/D log wr] vs. [D(1/T)/D
log wr] were linear for all of the decomposition steps. The energy
of activation Ea was calculated from the slopes of these plots for
all stages and the order of reactions (n) determined from the inter-
cept, showing first order reaction over the entire range of decompo-
sition for all of the complexes. A typical plot for the thermal
degradation of HPC1 is shown in Fig. 1. All the complexes have neg-
ative entropy according to the kinetic data obtained from DTG
curves, which specify that the synthesized complexes have higher
controlled systems than reactants and are stable [49].
The thermal behavior of Cu(II) complexes
The thermal decomposition data of all the complexes are sum-
marized in Tables 5 and 6. Thermogravimetric analysis (TG and
DTG) representative curves corresponding to the complex (HPC1)
are presented in Figs. 2 and 3, respectively. The thermal fragmen-
tation scheme for the complexes is shown below;
Reflectance spectra and magnetic measurement
50—110 ꢆ
C
½CuðHL1ÞðPhÞðOHÞðH2OÞꢄꢃH2O
ðPhÞðOHÞðH2OÞꢄþH2O
½CuðHL1Þ
ƒƒƒƒƒ!
Removal of one mole lattice water molecules
The information regarding geometry of the mixed-ligand com-
plexes has been obtained from their electronic spectral data along
with magnetic susceptibility measurements. Cu(II) complexes (d9
system) are known for their varieties of structures due to their var-
ious coordination numbers. Six-coordinated Cu(II) complexes pos-
sesses distorted octahedral geometry. Normal octahedral geometry
160—460 ꢆC
½CuðHL1ÞðPhÞðOHÞðH2OÞꢄ
½CuðHL1Þꢄ
O
ƒƒƒƒƒ!
Removal of one mole ph ligand;AOH and H2
þ OH þ H2O þ Ph

H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
325
was found for Cu(II) complexes [52,53], even though the known
preference for Jahn–Teller distortions in cases of trigonal and octa-
hedral geometry. A very weak low intensity absorption band asso-
ciated with d–d transition for Cu(II) complexes at 465, 532 nm was
typical octahedral transition its indicate the octahedral geometry
of complexes [54]. moreover, the electronic spectra of six coordi-
nate Cu(II) complexes have either D4h or C4v symmetry, and the
Eg and T2g level of the 2D free ion term will split into B1g, A1g,
B2g and Eg levels, respectively under the influence of the distor-
tion, which can be cause two transitions such as, 2B1g ? 2B2g
and 2B1g ? 2A1g. This supports the distorted octahedral Cu(II)
complex which is usual in the d9 system [55,56]. The electronic
spectra of Cu(II) complexes (HPC1–HPC6) show three important
bands. Low intensity broad band in the region ꢅ18,000 cmꢁ1 is as-
signed as 10 Dq band corresponding to 2Eg ? 2T2g transition [57].
There is a high intensity band in the region ꢅ24,000 cmꢁ1 due to
symmetry forbidden ligand ? metal charge transfer transition
[58]. The band above 27,000 cmꢁ1 is assigned as ligand band.
Therefore distorted octahedral geometry around Cu(II) ion is sug-
gested on the basis of electronic spectra [59], which is further
ascertain by its magnetic moment of the Cu(II) complexes lies in
between 1.82 and 1.96 BM range. These values are typical of mono-
nuclear Cu(II) compounds with d9 electronic configuration. The ob-
served magnetic moments of all complexes correspond to
characteristic high-spin octahedral complexes. However, these val-
ues are slightly higher than the expected spin-only values due to
spin–orbit coupling contribution [60]. Thus the electronic spectral
data and magnetic moment data support the octahedral geometry
of the all complexes.
characteristics of the crystal w3x. Yang and Dang [61] were re-
cently reported the X-ray powder diffraction studies for structure
of hexa-coordinated Tin(IV) complex in which the ligand adopts
the most stereo-chemically favorable orientation. On the basis of
the X-ray powder diffraction study, proposed structure as per
Fig. 5 suggested for the complexes.
Antimicrobial
The examination of the data (Table 2) revealed that majority of
the compounds showed good antibacterial and antifungal activity
when compared with standard drugs. Transition metal complexes
posses higher antimicrobial activity compared to the coumarin
derivatives may be due to the change in structure by coordination
and chelating tends to make metal complexes act as more powerful
and potent bactereostatic agents, thus inhibiting the growth of the
microorganisms [62,63]. According to which the polarities of the li-
gands and the central metal atoms are reduced through charge
equilibration over the whole chelate ring. The process turns that
increase the lipophilic character of the central metal atom which
favors its permeation through the lipid layer of the microorganism
and thus destroying them more aggressively. As shown in Table 2,
Complexes HPC2, HPC3 and HPC4 were found to be higher potency
against most of the employed strains. In particular, against Gram
Positive bacteria S. Pyogenes, complexes HPC2 and HPC3 have
shown superior activity upon comparison with standard drugs.
Unfortunately, none of the synthesized ligands and its transition
metal complexes were found sufficiently potent to inhibit Gram
negative bacteria. Furthermore, against fungal pathogen A. niger,
complex HPC1 showed significant activity. While, ligand HL4 and
complexes HPC3 as well as HPC4 displayed excellent activity upon
comparison with Nystatin against both fungal pathogen.
X-ray diffraction studies
The investigation of the structure–activity relationship of anti-
bacterial screening revealed that the ligand HL1 was found to have
X-ray powder diffraction studies is carried out two find the fea-
sible lattice dynamics of the finely powdered compound HPC2
(Fig. 4). The observed inter planar spacing values (d-spacing) were
measured from the diffractogram of the compound. Furthermore,
the Miller indices h, k and l were assigned to each d value along
with 2-Theta angles are given in Table 7. The results show that
the compound belongs to hexagonal crystal system having unit cell
parameters as a = 4.9168, b = 4.9168, c = 5.4089, maximum devia-
tion of 2-Theta = 0.025 and Alpha = 90, Beta = 90, Gama = 120 at
the wavelength = 1.540598. We have tried to isolate single crystal
of Cu(II) complex for accurate X-ray crystal study but could not
succeed to develop single crystal, it might be due to polycrystalline
nature of complex. It is difficult to grow good quality single crystals
of entitled Cu(II) complexes. In such cases, the powder X-ray
diffraction studies might be useful. Even with some inherent
limitations, this method yield valuable information about the
activity (MIC = 400
mL) towards S. pyogenes, (MIC = 70
(MIC = 200 g/mL) towards A. niger but after formation of complex
with Cu(II), resulted complex HPC1 have been found to posses in-
creased the potency (MIC = 200 g/mL) against P. aeruginosa,
(MIC = 40 g/mL) against S. pyogenes, (MIC = 40 g/mL) against B.
subtilis and (MIC = 100 g/mL) against A. niger. Same thing is ob-
served in case of ligand HL5 have shown activity (MIC = 200 g/
mL) against E. coli, (MIC = 200 g/mL) against P. aeruginosa and
(MIC = 70 g/mL) against B. subtilis but after formation of complex
with Cu(II), resulted increase the potency of complex HPC5
towards E. coli (MIC = 100 g/mL), towards P. aeruginosa
(MIC = 100 g/mL) and towards B. subtilis (MIC = 40 g/mL).
lg/mL) towards P. aeruginosa, (MIC = 100
lg/
lg/mL) towards B. subtilis and
l
l
l
l
l
l
l
l
l
l
l
Moreover, complex HPC2 having m-hydroxy phenyl ring at
3-position of coumarine nucleus have been found inactive against
E. coli, C. albicans and A. niger but changing the position of hydroxyl
group to p-position of phenyl ring (complex HPC3), resulted in-
crease the activity towards E. coli, C. albicans and A. niger. Similar
situation observed in case of complex HPC6 carrying o-nitro phe-
nyl ring at 3-position of coumarine moiety showed inactivity
against gram negative bacteria E. coli and P. aeruginosa, while
replacing the o-position of nitro group to p-position of phenyl
ring(complex HPC5), resulted increase the antibacterial potency
towards E. coli and P. aeruginosa.
Interestingly, the complexes HPC3, HPC4 and HPC5 with substi-
tutions at p-position of the phenyl ring displayed good inhibitory
action against most of the employed strains than (un)substitutions
at other position of phenyl ring as well as ligand HL4 and its com-
plex HPC4 carrying chloro substitution at p-position of the phenyl
ring showed better activity against both fungal pathogen.
Complexes HPC2 and HPC3 have been found chief antimicrobial
members against gram positive bacteria.
Fig. 1. Thermal degradation of HPC1.

326
H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
Table 5
Thermoanalytical data of Cu(II) complexes.
Complexes
TG range (°C)
DTGmax (°C)
Mass loss (% obs. (calcd.))
Assignment
[Cu(HL1)(Ph)(H2O)(OH)]H2O
50–110
160–460
460–800
108
290
487
2.82(2.51)
32.01(29.99)
38.59
Removal of one mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL1 ligand
[Cu(HL2)(Ph)(H2O)(OH)]2H2O
[Cu(HL3)(Ph)(H2O)(OH)]H2O
[Cu(HL4)(Ph)(H2O)(OH)]H2O
[Cu(HL5)(Ph)(H2O)(OH)]3H2O
[Cu(HL6)(Ph)(H2O)(OH)]2H2O
60–110
180–450
450–800
102
294
479
4.64(4.91)
30.69(29.33)
43.20
Removal of two mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL2 ligand
50–100
160–450
450–800
82
284
498
2.94(2.45)
31.49(29.33)
45.23
Removal of one mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL3 ligand
70–130
170–480
480–800
97
280
471
2.67(2.39)
28.32(28.63)
52.36
Removal of one mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL4 ligand
40–100
160–470
470–800
89
297
490
7.52(7.08)
29.85(28.22)
49.23
Removal of three mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL5 ligand
70–150
190–510
510–800
120
288
497
4.29(4.72)
28.63(28.22)
44.32
Removal of two mole lattice H2O molecule
Removal of one mole Ph ligand, AOH and H2O
Removal of HL6 ligand
Table 6
Kinetic parameters of Cu(II) complexes.
Complex
TG range (°C)
Ea (kJ molꢁ1
)
n
A (sꢁ1
)
Sꢀ (J Kꢁ1 molꢁ1
)
Hꢀ (kJ molꢁ1
)
Gꢀ (kJ molꢁ1
)
[Cu(HL1)(Ph)(H2O)(OH)]H2O
50–110
160–460
460–800
3.58
3.67
39.35
1.30
1.32
1.00
0.108
0.062
6.48
ꢁ102.45
ꢁ101.06
ꢁ97.37
0.576
0.021
31.26
37.66
45.36
126.01
[Cu(HL2)(Ph)(H2O)(OH)]2H2O
[Cu(HL3)(Ph)(H2O)(OH)]2H2O
[Cu(HL4)(Ph)(H2O)(OH)]H2O
[Cu(HL5)(Ph)(H2O)(OH)]3H2O
[Cu(HL6)(Ph)(H2O)(OH)]2H2O
60–110
180–450
450–800
3.76
6.31
42.57
1.42
1.12
1.37
0.127
0.037
5.83
ꢁ105.59
ꢁ102.36
ꢁ94.32
ꢁ101.04
ꢁ98.18
ꢁ93.27
ꢁ109.72
ꢁ95.62
ꢁ92.37
ꢁ104.25
ꢁ103.37
ꢁ90.46
0.541
0.054
34.78
35.85
43.47
135.56
50–100
160–450
450–800
3.87
4.23
51.26
1.07
1.27
1.52
0.185
0.023
7.54
0.743
0.86
39.82
39.77
42.18
142.48
70–130
170–480
480–800
3.78
9.45
47.29
1.39
1.35
1.12
0.165
0.071
4.67
0.876
0.073
41.31
36.45
52.16
123.92
40–100
160–470
470–800
3.35
6.57
53.78
0.98
1.23
1.03
0.147
0.065
6.54
0.593
0.062
38.54
33.73
48.56
127.47
70–150
190–510
510–800
3.56
7.82
49.17
1.12
1.41
1.08
0.173
0.035
7.78
ꢁ103.82
ꢁ97.32
ꢁ94.63
0.485
0.035
40.68
38.46
44.76
122.35
Fig. 2. TG curve of HPC1.

H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
327
Fig. 3. DTG curve of HPC1.
Fig. 5. Proposed 3D structure of complex.
Fig. 4. XRD pattern of HPC2.
reducing power compared to that of chloro, nitro or unsubstituted
one. Thus form the data obtained, the potency order on the basis of
various substitutions on 4-position of the phenyl ring is given as
AOH > ACl > ANO2 > AH. However, none of the compounds have
been found to show better activity compared to the standard
ascorbic acid.
Reviewing and comparing the activity data, it is worthy to men-
tion that the antimicrobial activity of the target complexes
depends not only on the bicyclic heteroaromatic pharmacophore
appended through aryl ring but also on the nature of the metal
coordinated with ligands.
Antioxidant
Anti-tubercular activity
In vitro antioxidant activity of all the complexes HPC1–HPC6 is
shown in Table 2, exposed moderate to good ferric reducing power.
Among the tested compound, HPC3 showed more potency (FRAP
value 438 mM/100 g of sample), while HPC1 have less Frap value
(354 mM/100 g of sample). Furthermore, obtained data revealed
that hydroxyl group substituted derivatives show more ferric
The anti-tubercular activities of all the synthesized ligand and
its complexes were assessed against M. tuberculosis H37Rv at dif-
ferent concentration 3.125, 6.25, 12.5, 25, 50 and 100 lg/mL. The
Minimum Inhibitory Concentrations (MICs) of test compounds
compared with standard drugs Isoniazid, Ethambutol and
Table 7
Observed and calculated X-ray diffraction data of [Cu(HL2)(Ph)(H2O)(OH)]ꢃ2H2O complex.
h
k
l
2Theta (Obs.)
2Theta (Calc.)
2Theta (Diff.)
d (Obs.)
d (Calc.)
d (Diff.)
Intensity (Obs.)
0
1
1
0
0
0
0
0
1
0
1
2
16.8028
20.0306
26.9808
33.6646
16.375
20.845
26.622
33.097
0.4278
ꢁ0.8144
0.3588
5.27652
4.43294
3.30473
2.66234
5.40890
4.25807
3.34573
2.70445
ꢁ0.13238
0.17487
ꢁ0.041
10.46
10.93
20.81
7.67
0.5676
ꢁ0.04211

328
H.R. Dholariya et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 108 (2013) 319–328
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