Template synthesis, spectroscopic studies, antimicrobial, nematicidal and pesticidal activities of chromium(III) macrocyclic complexes

Article abstract of DOI:10.3109/14756366.2011.625022

A new series of Cr(III) macrocyclic complexes have been synthesized by template condensation of ligands 2-[4-chloro-2-(2-oxo-1,2-diphenyl- ethylideneamino)-phenylimino]-1,2-diphenyl-ethanone (ML¹) and 2-[4-fluro-2-(2-oxo-1,2-diphenyl-ethylidene

Full text of DOI:10.3109/14756366.2011.625022

Journal of Enzyme Inhibition and Medicinal Chemistry, 2013; 28(1): 33–40
© 2013 Informa UK, Ltd.
ISSN 1475-6366 print/ISSN 1475-6374 online
DOI: 10.3109/14756366.2011.625022
RESEARCH ARTICLE
Template synthesis, spectroscopic studies, antimicrobial,
nematicidal and pesticidal activities of chromium(III)
macrocyclic complexes
Iffat Masih, Nighat Fahmi, and Rajkumar
Department of Chemistry, University of Rajasthan, Jaipur, India
Abstract
A new series of Cr(III) macrocyclic complexes have been synthesized by template condensation of ligands 2-[4-
chloro-2-(2-oxo-1,2-diphenyl-ethylideneamino)-phenylimino]-1,2-diphenyl-ethanone (ML1) and 2-[4-fluro-2-(2-oxo-
1,2-diphenyl-ethylideneamino)-phenylimino]-1,2-diphenyl-ethanone (ML2) respectively, with appropriate diamines
i.e. 1,2-phenylenediamine, 4- chloro 1,2-phenylenediamine and 4-fluro- 1,2-phenylenediamine in the presence of
CrCl3.6H2O. The ligands and their complexes have been characterized on the basis of elemental analyses, molecular
weight determinations, conductance and magnetic susceptibility measurements and spectral studies including
IR, ESR, electronic spectra and X-ray powder diffraction studies. On the basis of these studies, a six-coordinated
octahedral geometry has been proposed for all these complexes. The newly synthesized ligands and their complexes
have been screened for their antimicrobial, nematicidal and pesticidal activities. The results are indeed positive.
Keywords: Cr(III) macrocyclic complexes, spectral studies, antimicrobial activity, nematicidal activity, pesticidal
activity, minimum inhibitory concentration
Introduction
e present article deals with the synthesis, character-
ization and biological properties of chromium(III) macro-
cycliccomplexes.esecomplexeshavebeencharacterised
with the help of various physicochemical techniques. e
antibacterial and antifungal activities of the ligands and
their metal complexes have been determined by screen-
ing of the compounds against various bacterial and fun-
gal strains. e results obtained, were compared with
antibacterial and antifungal activities shown by standard
bactericide Streptomycin and fungicide Bavistin. ese
complexes were also evaluated for their nematicidal and
pestcidal activity and the results were quite encouraging.
e chemistry of macrocyclic ligands and their com-
plexes have been extensively studied in recent years.1,2
Template reactions have been widely used for the syn-
theses of macrocyclic complexes, where a transition
metal ion is used as templating agent.3 Macrocyclic
complexes of transition metal ions have attracted con-
siderable attention because of various applications in
catalysis,4 bioinorganic5 and supramolecular chemis-
try6 and a number of unique properties offered by the
macrocyclic, environment, such as extremely high ther-
modynamic stability and the ability to access unusual
oxidation states of a metal centre.7 Nowadays interest
is focused on the synthesis of macrocyclic complexes
with potential medicinal applications, as contrast-en-
hancing agents in magnetic resonance imaging (MRI),8
as N.M.R shift and relaxation reagents9 and as RNA
cleavage catalyst.10,11 Macrocyclic complexes of transi-
tion metals exhibit antibacterial,12 anticarcinogenic,13
antifertility,14 and antifungal15 activities.
Experimental
Material
All the chemicals used were of AnalaR grade. Chromium
chloride (CrCl3.6H2O) and various diamines were pur-
chased from Sigma–Aldrich. Solvents of analytical grade
were distilled from appropriate drying agents immedi-
ately prior to use.
Address for Correspondence: Dr. Nighat Fathmi, Department of Chemistry, University of Rajasthan, Jaipur 302004, India.
Tel: 91-141- 2704677(O), 91-141-2763337(R). Fax: 91-141-2708621. E-mail: nighat.fahmi@gmail.com
(Received 03 June 2011; revised 13 September 2011; accepted 13 September 2011)
33

34 I. Masih et al.
Synthesis of the ligands (ML1 and ML2)
Supplementary Figure S1. is figure has been drawn
with the help of Chem3D Ultra software.
e ligands (ML1 and ML2) were prepared by dissolv-
ing 1,2-diphenyl-1,2 ethanedione (benzil) (20 mmol,
4.20 g) in 40 mL of ethanol, then calculated amount
of diamines i.e. 4-chloro 1,2-phenylenediamine (10
mmol, 1.42 g) or 4-fluro 1,2-phenylenediamine (10
mmol, 1.26 g) were added respectively in 2:1 molar
ratio. e reaction mixture was heated under reflux for
4–6 h on a ratio head. It was then concentrated to half
of the volume. e solution was cooled and the excess
solvent was removed by slow evaporation by keeping
it in a desiccator overnight. e coloured crystalline
products so obtained were purified by recrystallization
in the same solvent and dried in vacuo. e analysis
and physical properties of these ligands are given in
Supplementary Table S1. e synthetic route of the
ligands has been shown in Scheme 1 and the structure of
2-[4-chloro-2-(2-oxo-1,2-diphenyl-ethylideneamino)-
phenylimino]-1,2-diphenyl-ethanone (ML1) is given in
Synthesis of the Cr (III) macrocyclic complexes
e complexes were synthesised by the template con-
densation of ligands 2-[4-chloro-2-(2-oxo-1,2-diphenyl-
ethylideneamino)-phenylimino]-1,2-diphenyl-ethanone
(ML1)or2-[4-fluro-2-(2-oxo-1,2-diphenyl-ethylideneamino)-
phenylimino]-1,2-diphenyl-ethanone (ML2) with various
diamines such as 1,2-phenylenediamine, 4-chloro 1,2-phe-
nylenediamine and 4-fluro 1,2-phenylenediamine in the
presence of CrCl3.6H2O.
Synthesis of the [Cr(C40H26N4Cl3F)]Cl complex
A weighted amount of methanolic solution of the ligand
ML1 (10 mmol, 2.63g) was taken in a 100mL round bottom
flask. e solution of the ligand was mixed with the metha-
nolic solution of 4-fluro 1,2-phenylenediamine (10 mmol,
0.63g) and CrCl3.6H2O (10 mmol, 1.33g). After addition of
Scheme 1. Synthetic route of the Cr (III) macrocyclic complexes
Journal of Enzyme Inhibition and Medicinal Chemistry

New series of Cr(III) macrocyclic complexes 35
all the reagents, the contents were boiled under reflux for
about 7–8h on a ratio head; the reaction mixture was con-
centrated to half of its volume and kept in a desiccator at
room temperature. e complex obtained as solids, were
washed with methanol and dried under vacuo.
spectra of the complexes were monitored on a Varian
E-4X band spectrometer, USA at SAIF, IIT Madras,
Chennai, and magnetic susceptibility was measured
on a Lakeshore VSM 7410 model 155 vibrating sample
magnetometer, USA at RSIC,IIT Chennai. e conduc-
tivity values were measured on 10−3 mol dm−3 solution
in DMF at room temperature on century digital con-
ductivity meter model CC601 Chandigarh, India.
Synthesis of the [Cr(C40H27N4Cl2X)]Cl complexes ( X = Cl, F)
To obtain this type of complexes the methanolic solu-
tion of ligand ML1 (10 mmol, 2.63 g) or ML2 (10 mmol,
2.55 g) was mixed with the methanolic solution of 1,2-
phenylenediamine (10 mmol, 0.54 g) in the presence of
CrCl3.6H2O (10 mmol, 1.33 g). After addition was com-
pleted, the contents were refluxed for 7–8h on a ratio
head. It was then concentrated to half of the volume by
removing the solvent and kept in a desiccator at room
temperature. e complexes obtained as solids, were
washed with methanol and dried under vacuo.
Biological assay
Test microorganism
All the compounds were evaluated for their antimicro-
bial properties. MIC was recorded as minimum con-
centration, which inhibits the growth of microorganism.
e results obtained were compared with those of the
standard drug Streptomycin for bacteria and Bavistin for
fungi. e microorganisms used were Escherichia coli
(ATCC25922), Bacillus subtilis (ATCC6633), Fusarium
oxysporum (ATCC7808) and Rhizopus nigricans
(ATCC6227b). e synthesised macrocyclic complexes
were also tested for the nematicidal and pesticidal activ-
ity against Meloidogyne incognita and fifth instar larva of
Corcyra cephalonica respectively.
Synthesis of the [Cr(C40H26N4Cl2X2)]Cl complex ( X = Cl)
is type of complex was prepared by mixing a metha-
nolic solution of ML1 (10 mmol, 2.63 g) with methanolic
solution of 4-chloro 1,2-phenylenediamine (10 mmol,
0.71 g) and CrCl3.6H2O (10 mmol, 1.33 g). e reaction
mixture was heated under reflux for 7–8 h. e reaction
mixture was concentrated to half of its volume. After
cooling, the solution was kept overnight in a desiccator
at room temperature. e complex obtained as solid, was
washed with methanol and dried under vacuo.
In vitro antibacterial activity
e newly prepared compounds were screened for their
antibacterialactivityagainstEscherichiacoli(ATCC25922)
and Bacillus subtilis (ATCC6633) by paper-disc plate
method.18 Each compound was dissolved in DMSO and
solutions of the concentrations (500 and 1000 ppm)
were prepared separately. Paper discs of Whatman fil-
ter paper (No. 42) of uniform diameter (5mm) were cut
and sterilised in an autoclave. e paper discs soaked
in the desired concentration of the complex solutions
were placed aseptically in the Petri dishes containing
nutrient agar media (agar 20g + beef extract 3g + pep-
tone 5 g) seeded with Escherichia coli (ATCC25922) and
Bacillus subtilis (ATCC6633) separately. e Petri dishes
were incubated at 37°C and the inhibition zones were
recorded after 24 h of incubation. e antibacterial activ-
ity of standard antibiotic Streptomycin was also recorded
using the same procedure. e medium with DMSO as a
solvent was used as a negative control. e experiments
were performed in triplicates. e % activity index for the
compounds was calculated by the formula given in equa-
tion 1 and the results are shown in the Figure 1a.
Synthesis of the [Cr(C40H26N4Cl2X2)]Cl complex ( X = F)
is complex was prepared by following the above pro-
cedure, using the ligand ML2 and 4-fluro 1,2-phenylene-
diamine in the presence of CrCl3.6H2O in 1:1:1 molar
ratio.
All the complexes were recrystallised from 1:1 molar
solution of methanol and benzene. e purity of the com-
plexes was checked by thin layer chromatography (TLC).
e analysis and physical properties of these complexes
are given in Supplementary Table S1. e template syn-
thesis of the complexes may be represented by the fol-
lowing scheme 1.
Analytical and physical measurements
e nitrogen and chlorine contents of the complexes
were estimated by the Kjeldahl’s and Volhard’s method,
respectively.16 e metal contents were estimated
gravimetrically.17 Elemental analysis of C and H were
performed at CDRI, Lucknow. Molecular weights were
determined by Rast Camphor method. Melting points
were determined by using capillaries in electrical
melting point apparatus. e electronic spectra were
recorded on an Ultraviolet visible spectrophotometer
752/752N, Mohali, India, infrared spectra of the ligands
and their complexes were recorded with the help of
FTIR-8400S Fourier Transform infrared spectropho-
tometer Shimadzu, Japan on KBr pellets. XRD were
measured on Panalytical make Xpert Pro 3040 Almelo,
Netherlands, electron paramagnetic resonance (EPR)
Zone of inhibition by test
compound (diameter)
(1)
× 100
% Activity index =
Zone of inhibition
by standard (diameter)
In vitro antifungal activity
e newly prepared complexes were also screened for
their antifungal activity against Fusarium oxysporum
(ATCC7808) and Rhizopus nigricans (ATCC6227b) by the
agar-plate technique.19 e media was prepared by dis-
solving starch (20 g), D-glucose (20 g) and agar-agar (20 g)
© 2013 Informa UK, Ltd.

36 I. Masih et al.
Figure 1. (a) % Activity index data for antibacterial activity of ligands and their complexes. (b) % Activity index data for antifungal activity
of ligands and their complexes.
in distilled water (1000 mL). e compounds were dis-
solved in 50, 100 and 200 ppm concentrations in DMSO
and then were mixed with the medium. e medium
was then poured into Petri plates and the spores of fungi
were placed on the medium with the help of inoculum’s
needle. ese Petri plates were wrapped in polythene
bags containing few drops of alcohol and were placed in
an incubator at 30 2°C. e controls were also run and
three replicates were used in each case. e fungal activ-
ity of each compound was compared with Bavistin as a
standard drug. e medium with DMSO as a solvent was
used as a negative control.
% activity index for fungal strain is also calculated with the
help of equation 1, which is presented in Figure 1b,
C −T
C
(2)
% of inhibition =
× 100
where C and T are the diameters of the fungal colony in
the control and the test plates, respectively.
Determination of minimum inhibitory concentration (MIC)
e minimum inhibitory concentration (MIC) is the lowest
concentration of the antimicrobial agent that prevents the
development of viable growth after overnight incubation.20
e determination of the MIC involves a semi quantita-
tive test procedure, which gives an approximation to the
least concentration of an antimicrobial needed to prevent
e linear growth of the fungus was recorded by mea-
suring the diameter of the fungal colony after 96h and the
percentage of inhibition was calculated by equation 2. e
Journal of Enzyme Inhibition and Medicinal Chemistry

New series of Cr(III) macrocyclic complexes 37
microbial growth. e minimum inhibitory concentration
was determined by microbroth dilution method.21 In this
method, the test concentrations of chemically synthesised
compounds were made from 100 to 3.125 µg /mL in the
DMSO. Inoculum of the overnight culture was prepared.
In a series of tubes, 1mL each of Cr(III) complex solution
with different concentrations was taken and 0.4mL of the
inoculum was added to each tube. Further 3.5mL of the
sterile water was added to each of the test tubes. ese
test tubes were incubated for 18h and observed for the
presence of turbidity. e absorbance of the suspension
of the inoculum was observed with spectrophotometer
at 555nm. e end result of the test was the minimum
concentration of the antimicrobial agent (test materials),
which gave a clear solution, i.e. no visual growth.22,23
containing 500 g of wheat cereals were labeled to indicate
the date of introduction of adults and new emergence.
On alternate days larvae were shifted to fresh jars so that
successive rearing jars can be maintained and insects of
known age can be obtained regularly. Pesticidal activity
of the synthesised compounds was tested by immersion
method. All the synthetic compounds were weighed and
dissolved in methanol to prepare 1000 mg L−1 stock solu-
tion. Further concentrations viz., 900, 800, 700, 600, 500,
400, 300, 200, 100 mg L−1 were prepared by serial dilution.
Twenty larvae were released in each Petri plate and then
one mL of each concentration of various compounds was
directly poured in each Petri plate with the help of a brush.
Petri plates with test solution were rotated vigorously and
were kept at 27 1°C and 70% relative humidity. Mortality
was observed after 96 h. Larva was considered dead if it
failed to respond to stimulus by touch. Control mortality
was corrected by using Abbott’s formula25 and data was
subjected to probit analysis according to Finney.26
Nematicidal activity
A step-by-step procedure24 was followed for obtaining
quantities of clean Meloidogyne incognita eggs. Brinjal
roots heavily infected by Meloidogyne incognita, were
washed thoroughly under running water and cut into
small pieces. e pieces were placed in a beaker in
100 mL of tap water. e suspension was shaken vigor-
ously for 5 min after adding 500 mL of 1% NaOCl and
then the suspension was poured quickly through nested
150- and 400-mesh sieves. Eggs that passed through the
400-mesh sieves were recovered by repeated sieving and
rinsing. e eggs that were retained on the 400-mesh
sieves were washed with sufficient quantities of distilled
water. From the sieves, eggs were eluted and transferred
to 40 mL of water. A centrifuge tube was filled two-thirds
with 20% sucrose solution and the egg–water suspen-
sion was centrifuged at 500 g for 5 min. At the junction
of sugar solution, a silver layer containing the suspended
eggs and egg suspension was removed with the help of
a pipette and quickly poured on to a 400-mesh sieve.
e eggs retained on the sieve were washed three times
thoroughly with distilled water and collected in a beaker.
A total of 230 eggs of nematode Meloidogyne incognita
were used per replicate sample and each treatment was
replicated three times. e experiment was conducted at
room temperature 30 2°C. e eggs were treated with
25, 50 and 100 ppm solution of the complexes for 24 h
and hatching of Meloidogyne eggs were noted. e nem-
aticidal property was calculated by using the equation 3,
% mortality observed
−% mortality in control
100 −% mortality in control
Corrected %
mortality
=
× 100
Result and discussion
Chemistry
e elemental analysis and spectral data suggested the
formation of the ligands (ML1 and ML2) and their mac-
rocyclic complexes of the type [Cr(C40H26N4Cl3F)]Cl,
[Cr(C40H27N4Cl2X)]Cl and [Cr(C40H26N4Cl2X2)]Cl, where
X = Cl, F. e resulting macrocyclic complexes are
coloured, solids, stable at room temperature and non
hygroscopic.12 ey are soluble in DMF and DMSO.
Molecular weight determination showed that they are
monomeric in nature. e values of molar conductance
measurements of 10–3M solution in DMF indicate that
the complexes are 1:1 electrolytes (Supplementary
Table S2).
Magnetic moment and electronic spectra
e magnetic moment of the chromium(III) complexes
lie in the range 3.70–3.83 B.M, which is close to the spin
only value, suggesting an octahedral geometry around
the chromium ion27. e electronic spectra of the high-
spin chromium(III) complexes display three spin allowed
HT ×100
NP (%) =
transitions in the range 16,550–17,880, 21,000–3300 and
HC
4
30,038–32,970, which may be assigned to A2g
→
4T2g
(F) v1, A2g → 4T1g (F) v2 and A2g → 4T1g (P) v3 transitions
respectively, suggesting an octahedral geometry around
Cr(III).28 Various ligand field parameters like Dq, B, and
β have been calculated and given in Supplementary
4
4
where NP is the nematicidal property, HC is the amount
of hatching in the control and HT is the amount of hatch-
ing in the test plate.
4
Pesticidal activity
Table S2. Energy of the first spin allowed transition A2g
→ 4T2g (F) v1 directly gives the value of 10Dq. Electronic
repulsion parameter is expressed in terms of Racah
parameter and “B” has been evaluated during these
studies. e nephelauxetic ratio β indicates that the com-
plexes have appreciable covalent character.
Fifth instar larvae of Corcyra cephalonica were obtained
from stock culture maintained at the storage section
of Division of Entomology, Durgapura Agricultural
Research Institute, Jaipur. Insects were reared on wheat
grain at 27 1°C and 70% relative humidity. Glass jars
© 2013 Informa UK, Ltd.

38 I. Masih et al.
results show that the compound belongs to “orthorhom-
bic” crystal system having unit cell parameters as a=9.05,
b=17.15, c=21.15, maximum deviation of 2θ=0.046 and
α=90, β=90, and γ=90 at wavelength=1.93728. Table
showing XRD measurement data of [Cr(C40H26N4Cl3F)]Cl,
is given in Supplementary Table S4.
ESR spectra
e electron spin resonance (ESR) spectra of the mac-
rocyclic complexes of chromium were recorded at room
temperature. ese consist of a single broad peak in each
case and from which the Lande splitting factor (“g” val-
ues) has been calculated. ese g values lie in the range
1.9783–1.9831 with giso (2.04), which are characteristic of
an octahedral geometry.29
Biological results and discussion
e results of antimicrobial activity are shown in
Supplementary Figures S4 and S5. All the ligands and
their Cr(III) complexes were sensitive against all the
fungal and bacterial strains. e antimicrobial screening
data indicate that the metal complexes are more potent
antimicrobial agents than the free ligands.
MIC values for the ligands and their chromium (III)
complexes are shown in Supplementary Figure S6.
Minimum inhibitory concentration of the ligands and
their metal complexes was determined against four
tested strains. Compound [Cr(C40H27N4Cl3)]Cl and
[Cr(C40H26N4Cl4)]Cl show low MIC values at 30 µg/mL
for bacterial strain Escherichia coli, Bacillus subtilis and
at 5.125 µg/mL for fungal strain Fusarium oxysporum.
Metal complexes are more active against fungal strains in
comparison to bacterial strains.
e biological activity of the ligands exhibited a
marked enhancement on coordination with the metal
ions against all the test bacterial/fungal strains, which
shows that metal chelates are more active than the
ligands. is may be explained by Tweedy’s Chelation
theory33 according to which chelation reduces the polar-
ity of the central metal atom because of the partial shar-
ing of its positive charge with the ligand,34 which favours
permeation of the complexes through the lipid layer of
cell membrane.35 Other factors such as solubility, con-
ductivity and dipole moment, which are affected by the
presence of metal ions may also be possible reasons for
increasing the biological activity of the metal complexes
as compared to the corresponding ligands.
IR- spectra
etentativeabsorptionfrequenciesoftheligandsandtheir
Cr(III) complexes along with their assignment are recorded
and listed in Supplementary Table S3. e bands due to
vas(NH2) at 3380cm−1, vs(NH2) at 3250cm−1 and v(C=O) in
the region 1670–1680cm−1 were present in the spectra of the
diamines and ligands respectively, but were absent in the
infrared spectra of all the complexes. e disappearance of
the vas (NH2), vs (NH2) and v(C=O) bands and appearance
of absorption band around 1610–1615cm−1 indicates the
formation of macrocyclic framework, as these bands may
be assigned to v(C=N).30 e value of absorption band due
to v(C=N) is lower than that usually occur for azomethine
group, which supports the coordination of this group to
the metal atom and formation of macrocyclic complexes.
e phenyl ring absorptions appear in the 1465–1495 and
1355–1390cm−1 region are assigned to vasymC6H5 and vsym
C6H5 respectively. e single band observed from 310 to
320cm−1 is due to v(Cr–Cl) vibration31 and bands at 415–
460cm−1 are assigned to v(Cr ← N).32
On the basis of analytical and spectral data the
structures of the complexes have been proposed.
Supplementary Figure S5 represents 3D structure of [Cr
(C40H27N4Cl3)] Cl macrocyclic complex. is structure is
also drawn with the help of Chem3D Ultra software.
X-ray powder diffraction studies
e possible lattice dynamics of the complex,
[Cr(C40H26N4Cl3F)]ClhasbeendeducedonthebasisofX-ray
powder diffraction studies and the XRD pattern of com-
pound [Cr(C40H26N4Cl3F)]Cl is given in Supplementary
Figure S3. e observed interplanar spacing values (“d”
in Å) have been measured from the diffractogram of the
compound and the Miller indices h, k, and l have been
assigned to each d value and 2θ angles are reported. e
e results of nematicidal activity indicate that the
newly synthesised complexes are more active in inhib-
iting the hatching of eggs as compared to the ligands
and the maximum hatching was recorded in the control
(H2O). e results are summarized in Table 1.
Table 1. Nematicidal activity and pesticidal activity of the ligands and their complexes.
Nematicidal activity
Hatching in Meloidogyne incognita (%)
Pesticidal activity
25 ppm
25.5
50 ppm
20.5
100 ppm
LC50
410
840
210
195
165
410
170
–
χ2
Corrected mortality (%)
Compound
C34H23N2O2Cl
14.0
0.274
0.431
0.547
0.684
0.150
0.49
55.55
50
C34H23N2O2F
22.2
19.0
15.0
[Cr(C40H26N4Cl3F)]Cl
[Cr(C40H27N4Cl3)]Cl
[Cr(C40H26N4Cl4)]Cl
[Cr(C40H27N4FCl2)]Cl
[Cr(C40H26N4F2Cl2)]Cl
control
20.2
18.5
–
–
–
–
–
60.11
65.66
76.77
65.66
70.22
–
17.9
15.0
15.1
12.5
18.6
14.0
19.6
16.4
0.282
1.142
LC, lethal concentration.
Journal of Enzyme Inhibition and Medicinal Chemistry

New series of Cr(III) macrocyclic complexes 39
6. Campbell K, McDonald R, Tykwinski RR. Functionalized
macrocyclic ligands for use in supramolecular chemistry. J Org
Chem 2002;67:1133–1140.
7. Paryzek WR, Patroniak V, Lisowski J. M etal complexes of polyaza
and polyoxoaza Schiff bases macrocycles. Coord Chem Rev
2005;249:2156–2175.
8. Kong D, Meng L, Song L, Xie Y. Synthesis, structure and antitumor
activities of a new macrocyclic ligand with four neutral pendent
groups: 1,4,7,10-tetrakisbenzyl-1,4,7,10-tetraazacyclododecane (L)
and its Co, Ni and Cu complexes. Trans Met Chem 1999;24:553–557.
9. Sharma K, Joshi SC, Singh RV. Synthesis, Characterization and
AntifertilityActivityofNewUnsymmetricalMacrocyclicComplexes
of Tin(II). Met Based Drugs 2000;7:237–243.
10. Rossiter CS, Mathews RA, Morrow JR. Uridine binding by Zn(II)
macrocyclic complexes: diversion of RNA cleavage catalysts. Inorg
Chem 2005;44:9397–9404.
Both the ligands and their chromium complexes
were also evaluated for pesticidal activity and they have
a potent inhibitory effect on growth and development
of Corcyra cephalonica larva. e LC50 values in mg L−1
are shown in Table 1. e data indicate that all Cr(III)
complexes exhibit greater pesticidal activity than the
respective ligands, but compound [Cr(C40H26N4Cl4)]Cl
was highly effective as a pesticide with LC50 165 mg L−1
against Corcyra cephalonica. A possible explanation is
that, the compound inhibit molting hormone of pest
larva36 i.e. ecdysis disruption.
Conclusion
11. Baker BF, Khalili H, Wei N, Morrow JR. Cleavage of the 5′ cap
structure of mRNA by a europium(III) macrocyclic complex with
pendant alcohol groups. J Am Chem Soc 1998;119:8749–8755.
12. Reddy PM, Shanker K, Rohini R, Ravinder V. Antibacterial active
tetraaza macrocyclic complexes of chromium (III) with their
spectroscopic approach. Int J Chem Tech Res 2009;1:367–372.
13. Chandra S, Pundir M. Spectroscopic characterization of
chromium(III), manganese(II) and nickel(II) complexes with a
nitrogen donor tetradentate, 12-membered azamacrocyclic ligand.
Spectrochim Acta A Mol Biomol Spectrosc 2008;69:1–7.
14. Chandra S, Gupta R, Gupta N, Bawa SS. Biologically relevant
macrocyclic complexes of copper spectral, magnetic, thermal and
antibacterial approach. Trans Met Chem 2006;31:147–151.
15. Chandra S, Gupta LK, Agrawal S. Synthesis spectroscopic
and biological approach in the characterization of novel [N4]
macrocyclic ligand and its transition metal complexes. Trans Met
Chem 2007;32:558–563.
16. Vogel AI. A Textbook of Quantitative Chemical Analysis, 6th
edition. Pearson Education Ltd.: ames Polytechnique, London,
2006, pp. 387.
17. Vogel AI. A Text Book of Quantitative Inorganic Analysis. Longmans
Green: ELBS London, 1962.
18. GaurS,FahmiN,SinghRV.Coordinationbehaviorofunsymmetrical
ligand complexes of diorganotin and diorganosilicon derived
from Schiff bases. Phosphorus Sulfur Silicon Relat Elem
2007;182:853–862.
19. Shrivastava S, Fahmi N, Singh R V. Studies on chromium(III)
complexes with active nitrogen, oxygen and sulfur donor
ketimines synthesized under microwave conditions. J Sulfur Chem
2010;31:515–524.
We describe the synthesis, characterization and bio-
logical activity of Cr(III) macrocyclic complexes. On
the basis of magnetic, analytical and spectral data an
octahedral geometry has been proposed for the Cr(III)
macrocyclic complexes. e antimicrobial activity
results indicated that the complexes showed promising
antibacterial and antifungal activities, but compound
[Cr(C40H27N4Cl3)]Cl and [Cr(C40H26N4Cl4)]Cl showed
highest activity against bacterial strain Escherichia coli
ATCC25922, Bacillus subtilis ATCC6633 (MIC = 30 µg/
mL) and fungal strain Fusarium oxysporum ATCC7808
(MIC = 5.125 µg/mL). e enhanced activity of the
macrocyclic complexes than the parent ligands has
been explained on the basis of chelation theory. e
newly synthesised complexes exhibited consider-
able nematicidal and pesticidal activity. Compound
[Cr (C40H26N4Cl4)]Cl was found to be highly effective
as a pesticide with LC50 165 mg L−1 against Corcyra
cephalonica.
Declaration of interest
e authors are grateful to UGC, New Delhi for financial
assistance through grant No: 36 - 282/2008 (S.R.).
20. Greenwood D, Slack R, Peutherer J. Medical microbiology. A
guide to microbial infections: pathogenesis, immunity, laboratory
diagnosis and control. 15th ed. Edinburgh: ELST Publishers;
1997.
21. Shanker K, Rohini R, Ravinder V, Reddy PM, Ho YP. Ru(II)
complexes of N4 and N2O2 macrocyclic Schiff base ligands: their
antibacterial and antifungal studies. Spectrochim Acta A Mol
Biomol Spectrosc 2009;73:205–211.
22. Davidson PM, Parish ME. Methods for testing the efficacy of food
antimicrobials. Food Technol 1989;43:148–155.
23. Collins CH. Antibiotics and antibacterial substances. In:
Microbiological Methods. Butterworths, London, 1964, pp.
296–305.
24. Jain M, Gaur S, Singh VP, Singh RV. Organosilicon(IV) and
organotin(IV) complexes as biocides and nematicides: Synthetic,
spectroscopic and biological studies of N∩N donor sulfonamide
imine and its chelates. Appl Organometal Chem 2004;18:73–82.
25. Abbott WS. A method of computing the effectiveness of an
insecticide. J Econ Entomol 1925;18:265–267.
References
1. Paryzek WR, Patroniak V, Lisowski J. M etal complexes of polyaza
and polyoxaaza Schiff base macrocycles. Coord Chem Rev
2005;249:2156–2175.
2. Masih I, Fahmi N. Synthesis, spectroscopic studies and
electrochemistry of palladium (II) macrocyclic complexes derived
fromanewtetraazahalogensubstitutedligandsbytemplatemethod
and their antimicrobial and pesticidal activities. Spectrochim Acta
A Mol Biomol Spectrosc 2011;79:940–947.
3. Singh DP, Kumar R, Malik V, Tyagi P. Template synthesis,
spectroscopic studies and biological activities of macrocyclic
complexes derived from thiocarbohydrazide and glyoxal. J Enzy
Inhib Med Chem 2007;221:77–182.
4. Anbu S, Kandaswamy M, Suthakaran P, Murugan V, Varghese B.
Structural, magnetic, electrochemical, catalytic, DNA binding
and cleavage studies of new macrocyclic binuclear copper(II)
complexes. J Inorg Biochem 2009;103:401–410.
26. Finney DJ. Probit Analysis, 3rd edn. Univ Press: Cambridge, UK,
1971, 333.
27. Figgis BN. Introduction to Ligand Field eory. Wiley, New York,
1978.
5. Singh RV, Chaudhary A. Biologically relevant tetraazamacrocyclic
complexes of manganese: synthetic, spectral, antimicrobial,
antifertility and antiinflammatory approach. J Inorg Biochem
2004;98:1712–1721.
© 2013 Informa UK, Ltd.

40 I. Masih et al.
28. Fabretti AC, Preti C, Tassi L, Tosi G, Zannini P. Magnetic and
spectroscopic studies on copper(II) and chromium(III) complexes
with sulfur chelating ligands. Aust J Chem 1986;39:605–612.
29. El-Ajaily MM, Maihub AA, Hudere SS, Bensaber SM. Nickel
II chelate of Schiff base derived from 4-dimethyl-amino-
benzaaldehyde with systeine. Asian J Chem 2006;18:2427–2430.
30. BorisovaNE,ReshetovaMD,UstynyukYA.Metal-freemethodsinthe
synthesis of macrocyclic schiff bases. Chem Rev 2007;107:46–79.
31. Bhoon YK. Magnetic and EPR properties of Mn(II), Fe(III), Ni(II)
and Cu(II) complexes of thiosemicarbazone of α-hydroxy-β-
napthaldehyde. Polyhedron 1983;2:365–368.
33. Geeta B, Shravankumar K, Reddy PM, Ravikrishna E, Sarangapani
M, Reddy KK et al. Binuclear cobalt(II), nickel(II), copper(II) and
palladium(II) complexes of a new Schiff-base as ligand: synthesis,
structural characterization, and antibacterial activity. Spectrochim
Acta A Mol Biomol Spectrosc 2010;77:911–915.
34. Keshavan B, Gowda HK. Synthesis, spectral and fungicidal
studies on dioxobridged binuclear niobium (V) and tantalum
(V) complexes of N-alkylphenothiazines. Turk J Chem 2002;26:
237–243.
35. Varnes AW, Dodson RB, Wehry EL. Interactions of transition-metal
ions with photoexcited states of flavins. Fluorescence quenching
studies. J Am Chem Soc 1972;94:946–950.
36. Guerrero A, Rosell G. Biorational approaches for insect control by
enzymatic inhibition. Curr Med Chem 2005;12:461–469.
32. ShrivastavaS,FahmiN,SinghD,SinghRV.Structural,spectroscopic,
and biological aspects of S N donor Schiff-base ligands and their
chromium(III) complexes. J Coord Chem 2010;63:1807–1819.
Journal of Enzyme Inhibition and Medicinal Chemistry