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with biological, pharmacological and analytical applications [9,10].
A number of triazine analogues examined for metal ion extraction
we have reviewed as well [11,12]. Some triazine derivatives with
pyrazole, functioning at the least conventional habiliments, are
screened and identified as potential inhibitors of photosynthetic
electron transport [13].
In recent years, quest to design and develop the non-linear
optical materials, have increased, to meet the current demand
due to their widespread advantage in many high-profile areas
such as high-speed information processing, optical communica-
tions and optical data storage. Researches, of late, suggest that
the criterion for the compound to exhibit NLO activity is non-
its complexes were determined by the modified version of powder
technique at IISc, Bangalore.
Synthesis of ligand (L)
2-Phenylamino-4,6-dichloro-s-triazine [19] (0.001 mol, 2.4 g)
in 20 ml of ethanol was added drop wise to an ethanolic solution
of 3,5-dimethyl pyrazole (0.002 mol, 2.12 g). The mixture was
refluxed on water bath for 4 h and the reaction was monitored
by TLC. The solution was allowed to stand at room temperature
and the solid obtained was washed with ethanol and recrystallized
from ethanol (Yield 75%) (Fig. 1).
centrosymmetric and D–p–A system. In addition to organic
materials, transition metal complexes have also been found to
be effective in this regard [14]. Taking into perspective of the
aforementioned advantages, spotlight is now on s-triazine’s
derivatives owing to their impeccable hyperpolarizabilities and
better transparency [15]. Besides, the easily polarizable aromatic
Synthesis of [ML] and [ML2]Cl2 type metal complexes: general
procedure
Hot ethanolic solution of ligand (0.001 mol/0.002 mol) and hot
ethanolic solution of the corresponding metal(II) chlorides
(0.001 mol) were added together with constant stirring. The
mixture was refluxed for 6 h at 70–80 °C. On cooling, characteristic
colored solid metal complexes of type [ML] and [ML2]Cl2 were
precipitated out. The precipitated metal complexes were filtered,
washed with cold ethanol and dried under vacuum. Purity of the
complexes was checked by TLC (Fig. 2).
p-system, another matchless feature of s-triazine is that due to
its -deficient nature, it can act as an auxiliary acceptor in NLO
p
chromophores [16]. Further advantages in considering the s-tri-
azine as central moiety is its symmetric nature by which it will
be possible to chemically tune its NLO nature by mono- or
di- substitution [17,18]. Hence s-triazine derivatives, we regard,
a first choice.
In order to promote the NLO response of s-triazine,3,5-dimethyl
pyrazole is introduced into triazine core. Hence the ligand 4,6-
bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-phenyl-1,3,5-triazin-2-amine,
we have synthesized by the condensation of 2-phenylamino-4,
6-dichloro-s-triazine and 3,5-dimethyl pyrazole reveals NLO prop-
erty and its pharmacological significance. This paper reports, the
spectroscopic characteristics of 4,6-bis(3,5-dimethyl-1H-pyrazol-
1-yl)-N-phenyl-1,3,5-triazin-2-amine chelated metal(II) complexes
and their NLO activity and biological screening.
Nonlinear optical property
The SHG efficiency of the ligand and its metal(II) complexes
were determined by the modified version of the powder
technique developed by Kurtz and Perry [20]. The samples were
ground into powder and packed between two transparent glass
slides. An Nd:YAG laser beam of wavelength 1064 nm was passed
through the sample cell. The transmitted fundamental wave was
absorbed by a copper(II) sulphate solution, which removes the
incident 1064 nm light and Filter BG-38 removing any residual
1064 nm light. Interference filter band width was 4 nm and for
central wavelength of 532 nm. Green light was finally detected
by the photomultiplier tube and displayed on the oscilloscope.
The second harmonic signal was detected by a photomultiplier
tube and displayed on a storage oscilloscope. The efficiency of
the sample was compared with microcrystalline powder of KDP
and urea. The input energy used in this particular set-up was
2.2 mJ/pulse.
Experimental
Materials and methods
Reagents such as Cyanuric chloride and various metal(II) chlo-
rides were of Merck products. Elemental analyses were performed
by the use of Perkin-Elmer CHN analyzer. The EI-mass spectra were
recorded on Jeol-GC MATE-2 Instrument. 1H NMR spectrum of the
ligand was recorded at 300 MHz on Bruker DRX-300 spectrometer
in DMSO-d6 by employing TMS as internal standard. IR spectra of
the samples were recorded on Jasco FT-IR spectrophotometer in
4000–400 cmꢁ1 range using KBr pellet. The UV–Vis spectra were
obtained on a Jasco V-530 spectrophotometer using DMSO as a sol-
vent. The ESR spectra of powder copper(II) complexes were
recorded with Varian, USA-E-112 ESR Spectrometer at 300 and
77 K by using DPPH (Diphenylpicrylhydrazyl) as the g-marker.
Magnetic susceptibility of the complexes was determined by MS1
Mark Guoy balance using copper sulphate as calibrant. Effective
Antibacterial and antifungal activity
The biological screening effects of the synthesized compounds
were evaluated by well diffusion method [21]. Bacillus subtilis,
Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermi-
dis, Streptococcus mutans, Escherichia coli, Enterobacter aerogenes,
Klebsiella pneumoniae, Proteus vulgaris, Cryptococcus neoformans,
Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens,
Shigella flexneri, Vibrio cholera, Vibris parahaemolyticus, were used
for bacterial test. Antifungal activity was evaluated against
Aspergillus niger, Candida albicans, Penicillium oxalicum and
Candida neoformans. All the bacterial strains mentioned above
were incubated in Nutrient Broth (NB) at 37 °C for 24 h and fungal
isolates were incubated in PDA broth at 28 °C for 2–3 days. The
wells each of 5 mm in diameter were made in Muller Hinton
magnetic moments were calculated using the formula
leff = 2.28
(v
MT)1/2, where vM is the corrected molar susceptibility. Cyclic
voltammetry measurements were carried out at room temperature
by model CH 608 C instrument in DMSO under nitrogen atmo-
sphere using three electrode cell containing a Ag/AgCl reference
electrode, platinum wire auxiliary electrode and a glassy carbon
working electrode with tetrabutylammonium perchlorate (TBAP)
as supporting electrolyte. The molar conductance of the complexes
was carried out using a Systronic conductivity bridge at room tem-
perature in DMSO. The antimicrobial activities of the ligand and its
metal complexes were carried out by well-diffusion method. The
SHG (Second Harmonic Generation) efficiency of the ligand and
agar using cork borer. The test solution was prepared in 10ꢁ3
concentration (DMSO) and then 100 of the solution was
transferred into each well. The plates were incubated for 24 h at
37 °C and examined for clear inhibition zone around the well.
The assay was carried out in duplicate for all the test organisms.
M
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