# Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal

I Md Zahid, C Amirtha Kumar, R Mohan Kumar

► To cite this version:

I Md Zahid, C Amirtha Kumar, R Mohan Kumar. Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal. Mechanics, Materials Science & Engineering Journal, 2017, 9, 10.2412/mmse.59.74.247. hal-01503662

HAL Id: hal-01503662

https://hal.science/hal-01503662v1

Submitted on 7 Apr 2017

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons CC BY 4.0 - Attribution - International License
# Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal

I. Md. Zahid¹, C. Amirtha Kumar¹, R. Mohan Kumar¹,ᵃ

1 – Department of Physics, Presidency College, Chennai-600 005, India

a – mohan66@hotmail.com

<figure><img src="image_2.png" /></figure>

DOI 10.2412/mmse.59.74.247 provided by [Seo4U.link](https://link.springer.com/10.2412/mmse.59.74.247)

**Keywords:** growth from solution, X-ray diffraction, nonlinear optics.

**ABSTRACT.** The proton transfer or H-bonded complex of 2-aminoanilinium benzoate (OPDB) was synthesized from O-phenylenediamine as donor and benzoic acid as acceptor. OPDB crystals were grown by solution growth technique. The cell parameters and crystalline perfection of the grown crystal were studied by single crystal and powder X-ray diffraction analyses. The title compound was classified into orthorhombic crystal system with non-centrosymmetric P2₁2₁2₁ space group. FTIR spectral analysis revealed the existence of functional groups and their corresponding vibrational modes have been assigned. The optical transmission properties of the crystal were studied by UV-Vis spectral analysis. Laser induced damage threshold of the grown crystal was estimated using Nd:YAG laser source. The second harmonic generation efficiency of the grown crystal was studied by Kurtz-Perry test.

**Introduction.** Current research in nonlinear optics (NLO) is at the forefront because of its importance in providing the key functions of frequency shifting, optical modulation, optical switching and optical memory for emerging technologies in the areas such as telecommunication, signal processing, and optical interconnections. Also organic nonlinear optical materials are attracting a great deal of attention towards such key functions in comparison with their inorganic counterparts [1,2]. One of the main advantages of organic materials is that they permit one to modify the chemical structure with large physical structural diversities desired for required NLO properties. In addition to the requirement for linear and nonlinear optical properties, high priority is given to crystal structures which belong to non-centrosymmetric class for the application of quadratic nonlinear optical effects and crystals having active SHG efficiency [3]. The second harmonic generation is a nonlinear optical effect that occurs when laser radiation strikes the surface of a material and a fraction of incident lights frequency is doubled [4,5]. In recent years, much effort has been directed towards the design and development of highly efficient organic NLO materials that promotes non-centrosymmetric crystal packing enabling easier and faster bulk crystal growth. Among the various classes of organic materials, amino derivative crystals constitute a family in which aminoanilinium coordination compounds has shown wide range of NLO applications. Interesting potentiality of crystals having orthorhombic system so that it exhibits optical nonlinearity. The pioneering strategy of such co crystallization process was proposed by Cara C.Evans and coworkers [6]. In the present investigation the growth, spectral and optical properties of 2-aminoanilinium benzoate (OPDB) crystal has been studied and results are presented.

**Experimental**

**Material Synthesis and Crystal Growth.** 2-aminoanilinium benzoate (OPDB) was synthesized from O-phenylenediamine (C₆H₈N₂, 10.81 g) as donor and Benzoic acid (C₇H₆O₂, 12.21 g) as acceptor by dissolving in 100 ml of ethanol. The solution was allowed to stir for 6 hr and then filtered.
The filtered saturated solution was covered by using polythene sheet with single perforation at the
center of the beaker for controlled evaporation and allowed to evaporate in the room temperature. In
a period of two weeks, colorless block-shaped crystal of the title compound was harvested. The
synthesis scheme and photograph of as grown crystal is shown in Fig. 1(a) & (b).

<figure><img src="image_3.png" /><figcaption>Fig. 1(a) Synthesis scheme of OPDB.</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>Fig. 1(b) Photograph of as grown OPDB crystal.</figcaption></figure>

**Results and Discussion**

**X-ray Diffraction Analyses.** The crystallographic lattice parameters of the grown OPDB
crystal were determined using Bruker Kappa APEXII CCD Single Crystal X-Ray Diffractometer and
it shows that OPDB crystal belongs to orthorhombic crystal system with non-centrosymmetric
P2₁212₁ space group. The estimated cell dimension are a = 6.0218(7) Å, b = 12.261 (1) Å,
c =16.637 (4) Å, V = 1224.0 (5) Å³ and it agree very well with the reported data [6]. The crystal was
then grounded finely and subjected to powder X-ray diffraction. The PANalytical X'Pert Powder
XRD system was used to record reflections from various planes and the hkl values were determined
using the inbuilt Highscore plus program. From the obtained powder X-ray diffraction spectrum
(Fig.2), the presence of well-consistent Bragg peaks at specific 2θ angles confirmed the crystallinity
of the grown crystal.

<figure><img src="image_5.png" /><figcaption>Fig. 2. Powder XRD pattern of OPDB crystal.</figcaption></figure>

**FT-IR Spectral analysis.** The infrared (IR) spectrum was recorded using JASCO FTIR 410
spectrometer (4000–450 cm⁻¹). KBr pellet technique was used for recording the infrared spectrum.
The assignments have been made on the basis of band position, shape and intensity in correlation
with the vibrational bands of structurally related molecules. The presence of aromatic ring in the
prepared compound was confirmed by following the IR absorption frequencies and the obtained
spectrum is shown in Fig.3. The broad peak appeared in the range of 3400-3600 cm⁻¹ shows the
presence of hydrogen bonded –OH group. The carbonyl stretching observed from the peak at 1645
cm⁻¹. The NH- bending of the amino group is affirmed by the peak appeared at 1589 cm⁻¹. The peaks
observed at 1498 cm⁻¹ and 1371 cm⁻¹ are due to aromatic C-H bending and stretching. The sharp peak obtained at 717 cm⁻¹ is due to C-H rocking vibration. The peaks corresponding to aromatic C=C and C-C vibrations appeared at 1165 and 650 cm⁻¹. Thus, the FT-IR spectrum confirmed the presence of synthesized compound as O-phenylenediamine benzoate and its characteristic vibrational frequencies are summarized in Table 1.

<figure><img src="image_6.png" /><figcaption>Fig. 3. Infrared spectrum of OPDB.</figcaption></figure>

<table><caption>Table 1. Infrared vibrational spectral assignments of OPDB.</caption><thead><tr><td>v IR(cm<sup>-1</sup>)</td><td>Assignments</td></tr></thead><tbody><tr><td>3400-3600</td><td>hydrogen bonded –OH group</td></tr><tr><td>1645</td><td>carbonyl stretching</td></tr><tr><td>1589</td><td>NH- bending of the amino group</td></tr><tr><td>1498 and 1371</td><td>aromatic C-H bending and stretching</td></tr><tr><td>717</td><td>C-H rocking vibration</td></tr><tr><td>1165 and 650</td><td>aromatic C=C and C-C vibrations</td></tr></tbody></table>

**UV visible transmission spectral studies.** The transmission spectrum of OPDB crystal was recorded using T90+Model Spectrometer in the wavelength range 190-900 nm. Fig.4 shows the UV- Transmission spectrum of the OPDB crystal. The higher transparency of the crystal, in the visible region is an important property for any nonlinear optical crystal for device fabrication. The cutoff wavelength was observed at 290 nm for the as grown OPDB crystal and found suitable for optoelectronic applications. Band gap energy (Eg) estimation illustrated about the conduction behavior of grown crystal. The band gap value of the material is very closely related to the material's atomic and electronic band structure. It was calculated using the relation.

$$E_g = hc/\lambda \qquad (1)$$

where h is the Planck's constant, c is the velocity of light and λ is the cut-off wavelength for OPDB.
The forbidden energy band gap ($E_g$) for the OPDB crystal was found to be 4.26 eV. Hence, the good transparency combined with low cutoff wavelength makes OPDB suitability for the nonlinear applications

<figure><img src="image_7.png" /><figcaption>Fig. 4. Uv-vis transmission spectrum of OPDB.</figcaption></figure>

**Second harmonic generation test.** The NLO property of the grown OPDB crystal was studied by Kurtz-Perry powder technique with KDP crystal as reference material. Finely powdered crystal of OPDB was densely packed in a micro-capillary tube of uniform bore. The second harmonic generation (SHG) measurement was carried out using 1064 nm Q-switched mode locked Nd:YAG laser. The pulse width of 8 ns and 10 Hz repetition rate with pulse energy of 2.8 mJ/pulse laser was made to fall normally on the sample cell. An intense green light ($\lambda$ = 532 nm) emission from the sample was detected by a photomultiplier tube which confirmed the second harmonic property of OPDB crystal. KDP powdered sample with identical size was used as reference material in the SHG measurement. The SHG output signal voltages of OPDB and KDP were measured to be 252 mV and 120 mV respectively. Thus, SHG efficiency of O-phenylenediamine benzoate was found to be 2.1 times higher than that of KDP crystal.

**Laser damage threshold.** One of the decisive criteria for a NLO crystal to perform as a device is its resistance to laser damage, since high optical intensities are involved in nonlinear processes. The multiple shot Laser damage threshold measurement was carried out for OPDB crystal using Nd:YAG laser system, which delivered laser pulses at 532 nm having pulse width 6 ns and repetition rate 10 Hz. The energy density was calculated using the relation,

$$ \text{Power density } P(d)=E/\tau A \qquad (2) $$

where E is the input energy (mJ), $\tau$ is the pulse width (ns) and A is the area of the circular spot size.

For OPDB crystal, the multiple shot laser damage energy density obtained from the Q-switched Nd:YAG laser was found to be 5.98 GW/cm². It was found that the laser damage threshold value of OPDB crystal is higher than standard potassium dihydrogen phosphate (KDP) crystal (0.20 GW/cm²).

**Summary.** Nonlinear optical 2-aminoanilinium benzoate single crystals were grown by slow evaporation method. The crystalline perfection and lattice parameters of the grown crystal were examined by X-ray diffraction studies. The modes of vibration molecule groups present in the
compound were confirmed by FTIR spectral analysis. The transmission percentage, lower cutoff wavelength, and optical band gap energy ($E_g$) of the grown crystal were estimated by UV-Vis spectral analysis. The second harmonic generation efficiency of the material was found to 2.1 times higher than that of standard KDP crystal. The surface laser damage threshold value for OPDB crystal was found to be 5.98 GW/cm², which will be useful for optical applications.

References

[1] P.N.Prasad, D.J.Williams, Introduction to Nonlinear Optical Effects in Organic Molecules and Polymers, Wiley, New York, 1991.

[2] D.S.Chemla, J.Zyss, Eds. Nonlinear Optical Properties of Organic Molecules and Crystals; Academic Press, New York, 1987.

[3] P.Vijayakumar, G.Anandha Babu, P.Ramasamy, Synthesis, crystal growth and characterization of nonlinear optical organic crystal: p-Toluidinium p-toluene sulphonate, Materials Research Bulletin 47 (2012) 957-962, doi: 10.1016/j.materresbull.2012.01.011

[4] N. Vijayan, R. Babu, R. Gopalakrishnan, P. Ramasamy, growth and characterization of Benzimidazole single crystals: a nonlinear optical material, J. Cryst. Growth 262, 2004, 490-498.DOI: 10.1016/j.crysgro.2003.08.082

[5] H. Nakatani, W.R. Bosenberg, L.K. Cheng, Appl. Phys. Lett. 53, 1988, 2587-2591.
DOI:10.1063/1.100535

[6] Cara. C. Evans, M. Bagieu-Beucher, R. Masse, J. F. Nicoud, Chem. Mater. 10, 1998, 847-854.
DOI:10.1021/cm970618

Cite the paper

I. Md. Zahid, C. Amirtha Kumar, R. Mohan Kumar, (2017 [Crystal Growth, Spectral and Optical Studies of 2-Aminoanilinium Benzoate Single Crystal](https://www.sciencedirect.com/science/article/pii/S0041-9707(17)70247-9), Vol 9. Doi [10.2412/mmse.59.74.247](https://www.sciencedirect.com/science/article/pii/S0041-9707(17)70247-9)