C. Karunakaran et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 120 (2014) 84–87
85
production of ATP, a molecule the body uses to store energy. Phos-
phorus works with the B vitamins. It also assists in the contraction
of muscles, in the functioning of kidneys, in maintaining the regu-
larity of the heartbeat, and in nerve conduction [12]. Therefore, the
synthesis of phosphated imidazole is of our interest.
With the rapid development of nanostructured materials and
nanotechnology in the fields of biotechnology and biomedicine in
3 4 2 3
recent years, iron oxides (Fe O and Fe O ), in particular, have re-
InF
diphenyl-1H-imidazole
mixture of naphthaldehyde (1 mmol), benzil (1 mmol),
ammonium acetate (1 mmol) and InF (1 mol%) was stirred at sol-
vent-free conditions at 80° C; progress of the reaction was moni-
tored by TLC. After completion of the reaction, the mixture was
cooled, dissolved in acetone and filtered. The product was purified
by column chromatography using benzene: ethyl acetate (9:1) as
3
-catalysed facile and rapid synthesis of 2-(naphthalen-1-yl)-4,5-
A
3
ceived considerable attention for their strong magnetic properties
and low toxicity [13–15]. The outstanding potential of these iron
oxide nanoparticles has stimulated the extensive development of
synthetic technology [16,17].
the eluent. M.p. 258°., Anal. calcd. for C25
5.24; N, 8.09. Found: C, 86.63; H, 5.21; N, 8.03. H NMR
(400 MHz, CDCl ): d 7.26–7.38 (m, 6H), 7.52–7.66 (m, 8H), 7.79
(d, J = 6.8 Hz, 1H), 7.93 (bs, 2H), 7.98 (d, J = 8 Hz, 1H), 8.82 (d,
18 2
H N : C, 86.68; H,
1
3
1
3
Superparamagnetic (Fe
3
O
4
and Fe
2
O
3
) nanoparticles are of inter-
J = 8 Hz, 1H), 10.41 (s, 10.4,).
3
C NMR (100 MHz, CDCl ): d
est for in vivo applications because they do not retain any magne-
tism after they are removed from the magnetic field [18–20]. The
nanoparticles of iron oxides have been extensively exploited as
materials of choice for ferrofluids, high-density information storage,
magnetic resonance imaging (MRI) [21], tissue-specific releasing of
therapeutic agents [22], hyperthermia [23], gene magnetofection
125.11, 126.00, 126.37, 126.71, 127.20, 127.55, 127.88, 128.45,
128.69, 129.06, 129.75, 129.95, 134.93. MS: m/z. 346 [M+].
Synthesis of phosphated imidazole (PI)
About 1 mmol of syrupy phosphoric acid was added to 1 mmol
of imidazole in ethanol. The reaction mixture was stirred under
room temperature for 1 h. The pale yellow precipitate phosphated
imidazole was washed with ethanol and dried at 110 °C.
[
24] and targeted drug delivery labeling [25] and sorting of cells,
and separation of biochemical products [26]. For these in vitro or
in vivo applications, high magnetic sensitivity, good biocompatibil-
ity and rich surface functionality are very crucially required [27].
The organic chelates (ligands) have a tendency to form metal com-
plexes with various metal ions in solution when they are first sorbed
onto a suitable support material, and play a very important role in
the preconcentration as well as the separation of analytes [28].
Phosphoric acid is used as the complexing agent. Which forms phos-
phated imidazole (PI) and finally the phosphated imidazole bound
Synthesis of Fe
About 1 mmol of phosphated imidazole in dimethyl sulphoxide
was added to 1 mmol of Fe nanoparticles suspended in di-
2 3
O – phosphated imidazole (PIBMN)
2 3
O
methyl sulphoxide under constant stirring for 3 h. The solid was
filtered, washed with dimethyl sulphoxide and dried at 110 °C.
Fe
2
O
3
(PIBMN). In this article the photophysical characteristics of
Result and discussion
the newly synthesized phosphated imidazole and phosphated imid-
azole bound magnetic nanoparticle were investigated by steady-
state absorption and emission spectroscopy as well as time resolved
fluorometry. From these experiments, the position of the spectral
Fig. 1 shows the powder X-ray diffraction (XRD) pattern of phos-
phated imidazole bound Fe
tally agrees with the standard diffraction pattern of maghemite
cubic -Fe structure. JCPDS card no. 39-1346 is the reference
2 3
O nanoparticles. The XRD pattern to-
maxima (kabs, kexc and kemi), lifetime (
s
), the rate constants of radia-
c
2 3
O
tive (k ) and nonradiative (knr) deactivation of synthesized phos-
r
used. The unit cell length is 0.83515 nm. Fig. 1 also displays the
powder XRD of the precursor used. The diffractogram is in agree-
phated imidazole and phosphated imidazole bound magnetic
nanoparticle have been determined and discussed in detail.
ment with that of
the reference employed. These results show that the binding of
the imidazole does not modify the crystal characteristics of Fe
nanoparticles. The average crystal size of the synthesized imidazole
bound Fe and that of the Fe nanoparticles are 34 and 39 nm,
respectively. The average crystallite sizes (L) of the synthesized
SnO have been deduced from the half-width of the full maximum
2 3
c-Fe O . Here too the JCPDS card no. 39-1346 is
Experimental
2 3
O
Spectral measurements
2
O
3
2 3
O
The infrared spectra were recorded with an Avatar 330-Thermo
Nicolet FT-IR spectrometer. The proton spectra at 400 MHz were
obtained at room temperature using a Bruker 400 MHz NMR spec-
trometer. Proton decoupled 13C NMR spectra were also recorded at
room temperature employing a Bruker 400 MHz NMR spectrome-
ter operating at 100 MHz. The mass spectra of the samples were
obtained using a Thermo Fischer LC-Mass spectrometer in FAB
mode. The cyclic voltammetry analysis was performed with CHI
2
(HWFM) of the most intense peak of the respective crystals using
Scherer’s equation L = Kk/bcosh, where K is the shape factor, D is
6
1
30A potentiostap-electrochemical analyzer at a scan rate of
ꢁ1
00 mV s
using 0.1 M tetra-(n-butyl)-ammonium hexafluoro-
+
3
phosphate as supporting electrolyte with Ag/Ag (0.01 M AgNO )
as the reference electrode and Pt electrode as the working elec-
trode under nitrogen atmosphere at room temperature.
The UV–vis absorption and fluorescence spectra were recorded
with PerkinElmer Lambda 35 spectrophotometer and PerkinElmer
LS55 spectrofluorometer, respectively. Fluorescence lifetime
measurements were carried out with a nanosecond time correlated
single photon counting (TCSPC) spectrometer Horiba Fluorocube-
0
1-NL lifetime system with NanoLED (pulsed diode excitation
source) as the excitation source and TBX-PS as detector. The slit
width was 8 nm and the laser excitation wavelength was
2
80 nm. The fluorescence decay was analyzed using DAS6
Fig. 1. Powder X-ray diffraction (XRD) pattern of phosphated imidazole bound
software.
2 3
Fe O nanoparticles.
Karunakaran
