Journal of Minerals and Materials Characterization and Engineering, 2012, 11, 769-773
Published Online August 2012 (
The Influence of Benzophenone Substitution on the
Physico-Chemical Characterizations of
8-HydroxyQuinoline NLO Single Crystals
M. J. Jarald Brigit Gilda1, S. Anbarasu2, Y. Samson3, Prem Anand Devarajan2*
1Department of Physics, Ponjesly College of Engineering, Alamparai, India
2Deparment of Physics, St. Xavier’s College, Palayamkottai, India
3Departmentof Physics, Annai Velankanni College, Tholayavattam, India
Email: *
Received February 12, 2012; revised March 20, 2012; accepted April 7, 2012
Single crystals of 8-HydroxyQuinoline (8-HQ) and Benzophenone substituted 8-HydroxyQuinoline (B8-HQ) are grown
by slow evaporation of acetone at room temperature. Coloured crystals of 8-HQ and B8-HQ with good optical quality
of dimensions 54 × 3 × 1.5 mm3 and 27 × 3 × 1 mm3 are harvested. Single crystal X-ray diffractometer was utilized to
measure the unit cell parameters and to confirm the crystal structure. The presence of various functional groups in the
molecule was ascertained by FTIR spectral analysis. The cut off wavelength of 8-HQ and B8-HQ was centered at 350
and 356 nm. The functional groups in the molecule are elucidated by 1H and 13C-NMR spectral analyses. Kurtz Perry
test confirms the SHG in8-HQ andB8-HQ single crystals.
Keywords: Crystal Growth; X-Ray Diffraction (XRD); FTIR; UV-Vis-NIR; 1H and 13C-NMRe
1. Introduction
Nonlinear optical materials (NLO) have wide applica-
tions in the area of laser technology, optical communica-
tion and in storage devices. The high non linearity makes
it possible for organic crystals to double the frequency of
Ga-Al-As diode lasers for generating blue light which is
an important coherent source [1]. One of the advantages
in working with organic materials is that they allow one
to fine-tune the chemical structures and properties for the
desired nonlinear optical properties. In addition, organic
crystals have large optical susceptibility, inherent ul-
trafast response and high optical threshold for laser
power as compared with inorganic materials. Moreover,
their lower cutoff wavelength and a wide transparency
window in the visible region makes the candidate mate-
rials subject for extensive investigation [2].
In this context 8-HydroxyQuinoline (8-HQ) has been
identified as an important material for NLO applications
in the visible and ultraviolet regions. M. Rajasekaran has
reported the growth of 8-HQ single crystal by slow
evaporation technique using chloroform as a solvent. The
cut off wavelength is below 400 nm [3]. Recently K.
Aravinth has reported that the cut off wavelength of
8-HQ is around 390 nm and the lattice parameters are a =
3.85 Å, b = 24.93 Å, c = 28.72 Å, V = 2754 Å. The
grown 8-HQ crystal belongs to orthorhombic system
with non-centro-symmetric space group Fdd2 [4]. Elena
M. Filip et al. have performed quantum chemical semi
empirical PM3 calculations optimization of 8-Hydroxy-
Quinoline (8-HQ) structure, dipolemoment, polarizability
and other physical parameters [5].
The sonochemical fabrication of 8-HydroxyQuinoline
(8-HQ) aluminium (Alq3) nanoflowers with high electro
generated chemiluminescence was reported by Chang-Jie
Mao et al. [6]. Due to the continuation of interest in the
supramolecular arrangements, a new crystal structure of
hydrated 8-HydroxyQuinoline chloride was synthesized
from a reaction mixture consisting of 2-chloro nicotinoyl
chloride and 8-HydroxyQuinoline (8-HQ) [7]. Addition-
ally the tunable photoluminescence from tris (8-HQ) al-
uminium (Alq3) blended thin films of Alq3 embedded in
poly methyl methacrylate matrix at different concentra-
tions are also investigated by J. G. Mahakhode et al. [8].
The interaction between donor 8-HQ and π acceptor
P-Nitrophenol has been investigated spectroscopically. It
was shown by 1H-NMR that 8-HQ with π PNP forms
complex of 1:1 stoichiometry. Infrared spectral data in-
dicates a charge transfer interaction between donor and
acceptor due to n – π* transitions by the formation of
radical ion pairs [9].
*Corresponding author.
Copyright © 2012 SciRes. JMMCE
In this paper, we report the results of our work on the
influence of physico chemical characterization studies of
benzophenone substituted 8-HydroxyQuinoline (B8-HQ)
NLO crystals along with characterization by single crys-
tal X-ray diffraction (XRD), Fourier transform infrared
(FTIR), UV-Visible-NIR and 1H & 13C-Nuclear magnetic
resonance (NMR) spectral measurements and NLO test
for the first time.
2. Experimental Details
The starting materials are commercially available (E-
Merck). The solvent evaporation technique was used to
grow single crystals of 8-HQ. The corresponding 8-HQ
salt was dissolved in acetone to prepare a saturated solu-
tion and the solution was filtered using Whatmann filter
paper. The filtered solution was then taken in a beaker
which was hermetically sealed to avoid the evaporation
of the solvent. Optically defect free good quality single
crystals of 8-HQ with reasonable dimensions were har-
vested in a month. Benzophenone (5 M) was substituted
with the solution containing 8-HQ and acetone. The
concentration of the growth solution was fixed at 3 M.
Within a month, seed crystals are formed due to sponta-
neous nucleation. In the present work, good optical qual-
ity crystals of pure 8-HQ and Benzophenone substituted
8-HQ crystals (B8-HQ) are harvested. Figures 1 and 2
show the photographs of asgrown pure 8-HQ and B8-HQ
3. Single Crystal XRD
The X-ray diffraction data was collected using an auto-
matic X-ray diffractometer, EnrafNonius CAD 4-MV 31
Bruker kappa APE XIII. The structure was solved by the
direct method using SHELXL program. It is observed
from the X-ray diffraction data that both pure 8-HQ and
Figure 1. Photograph of as grown pure 8-HQ single crystal.
Figure 2. Photograph of as grown B8-HQ single crystal.
Fdd2. The calculated lattice parameter values of pure
8-HQ and B8-HQ are presented in Table 1. The results
of the present work are in good agreement with the re-
ported values [4]. It is evident from Table 1, that the
doped sample has a slight variation in the cell volume.
The variation in the cell volume may be due to the in-
corporation of Benzophenone into 8-HQ crystal lattice.
4. Ftir Spectral Analysis
The FTIR spectroscopy study is effectively used to iden-
tify the functional groups present in the crystal and to
determine the molecular structure. In order to analyze
qualitatively the presence of the functional groups in
8-HQ and B8-HQ, FTIR was recorded using the Perkin
Elmer Model spectrum-100 in the range 450 - 4000 cm–1
and the corresponding spectra obtained are shown in
Figures 3 and 4 respectively. The FTIR spectrum of pure
8-HQ is presented in Figure 5. The aromatic C-H
stretching appears at 3029 cm–1. The band assigned at
1576 cm–1 is attributed to C=C ring stretching vibrations.
The C=N stretching vibrations appears at the region of
1694 cm–1.
The peak at 3743 cm–1 is designated to O-H stretching.
The peaks at 1271 and 1222 cm–1 are assigned to C-O
stretching vibration. The aromatic C-H plane bending
appears at 1163 cm–1. The C-H out of plane bending oc-
curs at 707 and 738 cm–1. The peak at 1433 cm–1 is as-
signed to O-H plane bending. The spectrum of B8-HQ is
shown in Figure 4. The spectrum carries nearly similar
features of pure 8-HQ spectra. An additional peak at
3057 cm–1 is observed which is due to the C=O stretch-
ing of Benzophenone. An interesting observation to be
mentioned here is all the peaks of Figure 4 are shifted to
a higher frequencies of 1 cm–1, and hence it can be stated
that there is harmonious existence of dopant Benzophe-
none into the crystal lattice of 8-HQ. Higher resolution of
peaks and enhancement of the bands between the region
3400 - 1500 cm–1 are also observed.
Table 1. XRD data for 8-HQ and B8-HQ single crystal.
Data 8-HQ B8-HQ
8-HQ crystals are orthorhombic with a space group o
a (Å) 3.84 3.85
b (Å) 24.97 24.98
c (Å) 28.68 28.71
α˚ 90˚ 90˚
β˚ 90˚ 90˚
γ˚ 90˚ 90˚
Crystal system Orthorhombic Orthorhombic
Volume (Å) 2749.97 2761.12
Space group Fdd2 Fdd2
Copyright © 2012 SciRes. JMMCE
Copyright © 2012 SciRes. JMMCE
grown pure 8-HQ single crystFigure 3. FTIR spectrum of as
Figure 4. FTIR spectrum of as grown B8-HQ single crystal.
5. UV-Vis–NIR Studies
The UV-Visible absorption s
8-HQ was recorded in the wavelength region 200 -
1500 nm using a VARIAN CARY 5E model spectro-
photometer and the obtained spectra are shown in Figure
6. When the absorbance is monitored from longer to shorter
wavelength, the absorption is found to be moderately low
in the visible region and the near infrared region of th
sirable property of materials
t off wavelength of 8-
HQ was found to be at 350 nm which is in agreement
with reported values [3,4] and the cut off wavelength of
B8-HQ crystals was centered at 356 nm which is a de-
sirable property for SONLO materials.
pectrum of pure 8-HQ and spectrum. This is the most de
possessing NLO activity. The cu
6. 1H and 13C-NMR Spectral Analyses
The 1H NMR spectra of 8-HQ and B8-HQ were meas-
ured in Tetramethylsilane using the instrument Bruker
AV III NMR spectrometer. 1H and 13C spectra of pure
8-HQ and B8-HQ are shown in Figures 5 and 7-9 re-
spectively. The structure of 8-HQ single crystal is
B8-HQ single
Figure 5. 13C NMR spectrum of as grown
500 1000
Wavelength (nm)
Pure 8-HQ
Figure 6. UV-Vis-NIR spectrum of as grown 8-HQ and
B8-HQ single crystal.
n 8-HQ single crystal.
shown in Figure 10. A slight variation in 1H-NMR spec-
tra is observed in the Benzophenone substituted spectra
of 8-HQ. The addition of peaks centered around 7.175
and 7.160 ppm may be attributed to the incorporation of
Benzophenone in the 8-HQ crystal lattice. Thus it is clear
from the spectra that the characteristic functional groups
of 8-HQ and B8-HQ are evident. In the 13C-NMR spectra,
the various functional groups in the carbon bonded net-
work of 8-HQ and B8-HQ are shown in Figures 5 and 9
respectively. A slight variation is observed in the B8-HQ
spectra. Thus it is ascertained from Figure 5, that the addi-
tion of ketone functional group is revealed in the spectrum.
Figure 7. 1H NMR spectrum of as grow
Figure 8. 1H NMR spectrum of as grown B8-HQ single crys-
Figure 9. 13C NMR spectrum of as grown pure 8-HQ single
Figure 10. Structure of 8-HQ single crystal.
Copyright © 2012 SciRes. JMMCE
Copyright © 2012 SciRes. JMMCE
. NLO Test
The NLO property of pure 8-HQ and B8-HQ were
measured by Kurtz Perry’s NLO test. ANd-YAG laser
beam of wavelength 1064 nm of pulse width 8ns and
repetition rate of 10 Hz was made to incident on the sample.
Second harmonic radiation generated by 8-HQ and B8-
HQ were focused by a lens and collected by a photomul-
tiplier tube. In our study, KDP was taken as a reference
crystal. The output power intensity of pure 8-HQ was
found to be 0.75 times that of KDP [4] and B8-HQ was
found to be 0.85 times that of KDP single crystal.
8. Conclusion
Single crystals of pure 8-HQ and B8-HQ were grown
successfully by slow evaporation technique at room
onth. The non-Centro-symmetric nature of the crystals
was confirmed by XRD. The various functional groups
assigned to 8-HQ and B8-HQ were confirmed by FTIR
spectral analysis. The UV-Vis-NIR studies show that the
cut off wavelength of 8-HQ is at 350 nm and that of B8-
HQ is at 356 nm. The protons and the carbon bonded
network in these samples were elucidated by 1H and 13C-
NMR spectral analysis. Studies pertaining to TG/DTA,
SEM, Dielectric and Photoconductivity are in progress.
9. Acknowledgements
One of the authors (M. J. Jarald Brigit Gilda) is pleased
to acknowledge Prof. I. Sebasdiyar, Head of the depart-
ment of physics, St. Xavier’s college, Palayamkottai and
(ASN),” Rasayan Journal of Chemistry, Vol. 1, No. 4,
2008, pp. 782-787.
[2] C. Sekar and R. Parimala Devi, “Effect of Silver Nitrate
(AgNO3) on the Growth, Optical, Spectral, Thermal and
Mechanical Properties of γ-Glycine Single Crystal,” Jour-
nal of Optoelectronics and Biomedical Materials, Vol. 1,
No. 2, 2009, pp. 215-225.
[3] M. Rajasekaran, P. Anbusrinivasan and S. C. Mojumdar,
“Growth, Spectral and Thermal Characterization of
8-HydroxyQuinoline,” Journal of Thermal Analysis and
Calorimetry, Vol. 100, No. 3, 2010, pp. 827-830.
temperature. Defect free, optically transparent single
crystals of 8-HQ and B8-HQ were harvested within a
Dr. Maniysundar, Principal, Ponjesly College of Engineer-
ing, for their constant help, support and encouragement.
[1] S. Palanisamy and O. N. Balasundaram, “Growth, Optical
and Mechanical Properties of Alanine Sodium Nitrate
“Growth of <201> 8-HydroxyQuinoline Organic Crystal
by Czochralski Method and Its Characterizations,” Jour-
nal of Thermal Analysis and Calorimetry, 2011, 7 p.
[5] E. M. Filip, I. V. Humelnicu and C. I. Ghirve, “Some
Aspects of 8-HydroxyQuinoline in Solvents,” Acta Chem-
ica Iasi, Vol. 17, 2009, pp. 85-96.
[6] C.-J. Mao, D.-C. Wang, H.-C. Pan and J.-J. Zhu, “Sono-
chemical Fabrication of 8-HydroxyQuinoline Aluminum
(Alq3) Nanoflowers with High Electrogenerated Chem-
iluminescence,” Ultrasonics Sonochemistry, Vol. 18, No.
2, 2011, pp. 473-476.
[7] J. M. S. Skakle, J. L. Wardell and S. M. S. V. Wardell,
“Formation of Ladders from R44(8) and R66(12) Ring
in 8-Hydroxyquinoliniumchloride Monohydrate: Com-
d Salts,” Acta Crystallographica Section C Crystal
Structure Communications, Vol. 62, 2006, pp. 312-314.
[8] J. G. Mahakhode, B. M. Bahirwar, S. J. Dhoble and S. V.
Moharil, “Tunable Photoluminescence from Tris (8-Hy-
droxyquinoline) Aluminum (Alq3),” Proceedings of Asian
Symposium on Information Display, New Delhi, 8-12
October 2006, pp. 237-239.
[9] I. M. Khan, N. Singh and A. Ahmad, “Spectroscopic
Studies of Multiple Charge Transfer Complexes of
8-HydroxyQuinoline with π-Acceptor P-Nitrophenol in
Different Solvents at Room Temperature,” Canadian
Journal of Analytical sciences and Spectroscopy, Vol. 54,
No. 1, 2009, pp. 31-37.
[4] K. Aravinth, G. Anandha Babu and P. Ramasamy,
parisons with the Supramolecular Arrangements in Re-