Synthesis, crystal structure and vibrational spectroscopy of a nonlinear optical crystal: l -arginine maleate dihydrate

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Optical Materials 30 (2008) 1001–1006 www.elsevier.com/locate/optmat

Synthesis, crystal structure and vibrational spectroscopy of a nonlinear optical crystal: L-arginine maleate dihydrate Z.H. Sun *, W.T. Yu, X.F. Cheng, X.Q. Wang, G.H. Zhang, G. Yu, H.L. Fan, D. Xu

*

Institute of Crystal Materials, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, PR China Received 3 January 2007; received in revised form 18 March 2007; accepted 18 May 2007 Available online 10 July 2007

Abstract From the aqueous solution containing L-arginine and maleic acid (C4H4O4), crystals of L-arginine maleate dihydrate were grown. The crystal structure was determined by single crystal X-ray diffraction. In the triclinic unit cell (space group P1), the molecule contains one L-arginine cation, one maleate anion and two water molecules. The crystal can be described as an inclusion complex from its layer structure. The basic unit in L-arginine layer is centrosymmetric and the maleate anions exist in coplanarity. Hydrogen bond plays a great role in the construction of the crystal and nonlinear optical properties. The crystal was characterized by infrared (IR) and Raman spectra. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. Powder second harmonic generation (SHG) experiment was investigated to explore its NLO properties.  2007 Elsevier B.V. All rights reserved. PACS: 61.10.i; 78.30.Jw; 65.40.b; 42.70.Mp; 81.70.Pg Keywords: L-arginine maleate dihydrate; X-ray diffraction; Hydrogen bonds; Infrared and Raman spectra; Thermal properties; Nonlinear optical properties

1. Introduction Over the past two decades, the discovery of the promising nonlinear optical (NLO) properties in L-arginine phosphate monohydrate (abbreviated as LAP, where L-arginine stands for (+(H2N)2CNH(CH2)3CH(NH2)COO)) [1] has stimulated an intense interest in this crystal family [2–8]. It has high NLO coefficients (>1 pm/V), high damage threshold (>15 J/cm2) and high angular sensitivity when compared to widely used potassium dihydrogen phosphate (KDP) for frequency conversion of infrared lasers. The deuterated LAP has been thought to be a promising candidate to replace the conversional KDP crystal that applied in UV region in many high-tech areas [9]. Some known or novel crystalline salts of L-arginine with inorganic acids were grown and characterized [10–14]. Especially in Ref. *

Corresponding author. E-mail address: [email protected] (Z.H. Sun).

0925-3467/$ - see front matter  2007 Elsevier B.V. All rights reserved. doi:10.1016/j.optmat.2007.05.028

[10] the complexes containing L-arginine were synthesized by evaporation at ambient temperature and the structural parameters were reported. In slightly different conditions, crystalline salts of L-arginine with organic acids were synthesized [15–19]. In order to widen the properties of LAP and discover novel crystals with better NLO properties, research on new crystals and growth mechanism are in process in our lab [20–22]. Many oxalates are reported to be active in second harmonic generation (SHG) [23] and it may be useful to study complexes with other carboxylic acids and their properties. Maleic acid with relatively large p-conjugation has attracted our attention. In this paper, the crystal structure and properties of the organic NLO crystal, L-arginine maleate dihydrate (whose molecular formula is C6H14N4O2 Æ C4H4O4 Æ 2H2O) will be reported. Its structure is determined by X-ray diffraction and the cell parameters are quite different from previously reported complex of malate [2]. The grown crystal is characterized by the infrared and Raman spectra. Its thermal properties

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are studied thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The powder SHG experiment of crystal is carried out to examine its NLO properties. 2. Experimental All the starting materials are of analytic reagent grade. The growth solution was prepared by dissolving L-arginine and maleic acid with the mole ratio fixed at 2:1 in deionized water, which was in an attempt to synthesize crystals contain two L-arginine molecules. The solution was left in an oven for several days at 40 C, thereby plane and colorless crystals were obtained. In order to obtain crystals with high quality used for X-ray diffraction, large single crystals with dimensions of 20 · 10 · 2 mm3 were grown from aqueous solution by the temperature-lowering method. The X-ray diffraction intensity data for a perfect crystal (0.25 · 0.23 · 0.19 mm3) were measured at 293 K on a Bruker APEX2 CCD area-detector diffractometer with a Mo ˚ . The x:2h scan technique Ka radiation, k = 0.71073 A was employed to measure 3711 reflections up to h = 27.60 and 1762 reflections were unique. The data were corrected for absorption employing a semi-empirical correction. The crystal structure was solved by direct methods and refined by a Full-matrix least-squares procedure based on F(0 0 0) employing 1697 reflections. SHELXS-97 and SHELXL-97 [24,25] were applied. Non-hydrogen atoms were refined with anisotropic positions were included in the model at their calculated positions. A single weighting scheme was applied, and the refinement continued until the final deviation factors, R and RW were 0.0303 and 0.0693, respectively. The infrared spectrum of the grown crystal was recorded on a Nicolet 750 FTIR spectrometer at room temperature in the 4000–500 cm1 range. Its Raman spectrum was registered using NXR FT-Raman spectrometer with InGaAs as a detector. The TGA and DTA experiments were carried out on a Diamond TGA/DTA Perkin Elmer instrument with a heating rate of flux 20 C/min from 20 to 650 C. Samples were weighed in a platinum crucible with a microprocessor-driven temperature control unit and a data station. The SHG measurement was performed using a Nd:YAG laser with fundamental radiation of 1064 nm as the optical source. The laser light was projected directly onto the sample powder. 3. Results and discussion The crystal data and details of the data collection for the crystal structure determination are listed in Table 1. The molecular configuration and projection along the a-axis are shown in Figs. 1 and 2, respectively. The selected bond lengths and torsion angles are listed in Table 2. The data of hydrogen bonds are presented in Table 3. Layer growth in molecular structure is shown in Fig. 3. In the molecule structure, both the a-amino and guanidyl groups are protonated. The C–N bond lengths (Table 2) in the guanidyl

Table 1 Crystal data and structure refinement Empirical formula Formula weight Temperature Wavelength Crystal system, space group Unit cell dimensions

Volume Calculated density Absorption coefficient F(0 0 0) Crystal size Theta range for data collection Limiting indices Reflections collected/unique Completeness to theta = 27.60 Absorption correction Max. and min. transmission Refinement method Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I > 2r (I)] R indices (all data) Absolute structure parameter

C10 H22 N4 O8 326.32 293(2) K ˚ 0.71073 A Triclinic, P1 ˚ a = 106.155(1) a = 5.2710(1) A ˚ b = 97.265(1) b = 8.0481(2) A ˚ c = 9.7942(2) A c = 101.649(2) ˚ 3 Z=1 383.42(2) A 1.413 Mg/m3 0.122 mm1 174 0.25 · 0.23 · 0.19 mm3 2.92–27.60 6 6 h 6 6, 10 6 k 6 10, 11 6 l 6 12 3711/1762 [R(int) = 0.0113] 99.0% Semi-empirical from equivalents 0.9773 and 0.9706 Full-matrix least-squares on F2 1762/7/220 1.022 R1 = 0.0303, wR2 = 0.0693 R1 = 0.0314, wR2 = 0.0700 0.2(11)

Fig. 1. The molecular configuration.

˚ with an average groups range from 1.324(3)–1.330(2) A ˚ , which is close to the expected value of value of 1.325 A ˚ . A typical characteristic structure feature is their 1.323 A interactions through hydrogen bonds (Table 3). It contains several kinds of hydrogen bonds among the negatively charged carboxylate groups, positively charged protonated guanidyl groups and a-amino groups. In the selection of hydrogen bonds, the recommendations of Zefirov [26] were followed. The literature declared that for N–H  O and O– H  O type bonds the H  O distances of strongest Vander Waals and weakest hydrogen bonds lie in the range 2.45– ˚ . From Table 3, one can see that the hydrogen bonds 2.15 A between maleic acid and L-arginine are dominant in the crystal. The hydrogen bonds between guanidyl and carboxylate groups are little weaker. Water molecule binds to the cations as an acceptor by weaker hydrogen bonds. These

Z.H. Sun et al. / Optical Materials 30 (2008) 1001–1006

1003

Fig. 2. The projection along the a-axis.

Table 2 ˚ ) and torsion angles () The selected bond lengths (A Bond lengths (A˚) C(1)–N(2) C(1)–N(3) C(2)–C(3) C(4)–C(5) C(5)–C(6) C(6)–O(2) C(10)–O(6) C(9)–C(8) C(7)–O(4) O(3)–H(6)

1.324(3) 1.330(2) 1.520(3) 1.531(3) 1.531(3) 1.262(2) 1.288(3) 1.333(3) 1.235(3) 1.25(5)

O(5)–C(10)–C(9)–C(8) C(10)–C(9)–C(8)–C(7) C(9)–C(8)–C(7)–O(3)

179.8(3) 0.4(4) 1.0(4)

C(1)–N(1) N(3)–C(2) C(3)–C(4) C(5)–N(4) C(6)–O(1) C(10)–O(5) C(10)–C(9) C(8)–C(7) C(7)–O(3) O(6)–H(6) O(6)–C(10)–C(9)–C(8) C(9)–C(8)–C(7)–O(4)

1.321(3) 1.454(3) 1.521(3) 1.496(3) 1.235(2) 1.222(3) 1.485(3) 1.495(3) 1.269(3) 1.15(5) 1.2(4) 179.9(2)

Fig. 3. Layers growth from molecular structure.

Table 3 Hydrogen-bonding data D

A

˚) D–H (A

˚) H–A (A

˚) D–A (A

N(4) N(1) N(1) N(4) N(2) N(2) N(3) N(4) O(3) O(7) O(7) O(7) O(8) O(8)

O(2) O(1) O(3) O(5) O(2) O(5) O(4) O(7) O(6) O(8) O(1) O(8) O(4) O(2)

0.89 0.86 0.86 0.89 0.86 0.86 0.86 0.89 1.28(4) 0.90(2) 0.87(2) 0.87(2) 0.87(3) 0.88(2)

1.98 2.18 1.98 2.23 2.10 2.08 2.10 1.92 1.13(4) 1.91(2) 2.35(4) 2.57(5) 2.01(2) 1.97(3)

2.843(2) 2.935(2) 2.843(2) 3.079(3) 2.948(2) 2.862(3) 2.955(2) 2.801(2) 2.407(2) 2.791(3) 3.081(3) 3.186(4) 2.873(3) 2.770(2)

interactions may have an effect on the crystal structure, which is similar to the case of patassiun hydrogen bis-trichloroacetate [27]. Figs. 2 and 3 show how hydrogen bonds connect the L-arginine layers with neighbor layers. The

L-arginine

layers are stabilized by almost parallel N– H  O hydrogen bonds between guanidyl and carboxylic groups. These hydrogen bonds interconnect the layers along the cell axis of intermediate dimensions, while the L-arginine molecules are interconnected along the shortest crystallographic axis by N(4)  O(2) hydrogen bonds in head-to-tail sequences. The maleic acid layers form strings with glide-related molecules. However, these strings in the layer do not interact among themselves directly. The carboxyl groups in maleic acid layers are connected with the main-chain atoms of two neighbor L-arginine molecules through N–H  O and O–H  O hydrogen bonds between amino acid and guanidyl groups. Each molecule is entirely surrounded by L-arginine molecules so that the complex may be described as an inclusion complex, which is essential to the mechanism of crystal growth. The torsion angles in maleate anion, O(6)–C(10)–C(9)– C(8), C(10)–C(9)–C(8)–C(7) and C(9)–C(8)–C(7)–O(3) are 1.2(4), 0.4(4) and 1.0(4), respectively. This means

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maleate anion exists in coplanarity. The similar result has been observed in many other complexes containing the maleic acid molecule [28–30]. However, the bond length ˚ ) is much longer than that of of O(3)–H(6) (1.25(5) A ˚ O(6)–H(6) (1.15(5) A). The former exists as a donor while the later is an acceptor, which is consistent with the hydrogen bond length between O(3) and O(6). This indicates that the hydrogen bond between O(3) and O(6) is asymmetric. The coexistence of both forms of carboxylic groups resulting breaking of central-symmetry appears to be a fruitful idea underlined by Guru Row [31]. The bond lengths and angles of L-arginine cation in the title crystal are close to those in L-arginine Æ 2H2O (abbreviated as LAW) [32]. LAW molecules are interacted with one another through guanidyl and carboxyl groups by hydrogen bonds along c-axis. The dipole orientation of the molecules is opposite due to the combined activities of the three 21 spiral axes. Although LAW crystallizes in a noncentrosymmetric space group, there is no distinct NLO effect in LAW crystals. Yet in the title crystal, L-arginine and maleic acid molecules arrange in order. The maleate anion with relatively large p-conjugation optimizes the orientation of L-arginine, namely the optically active L-arginine is arranged with the asymmetrical guanidyl and carboxyl groups with maleate anion. Therefore, compared with LAW, the introduction of maleate anion greatly enhances its NLO properties and susceptibility. Water molecules are involved in the interactions between L-arginine and maleic acid layers through N–H  O and O–H  O hydrogen bonds. In the cell unit, both water molecules are interacted with Larginine and maleic acid layers, while hydrogen bonds connect them together. The infrared and Raman spectra are shown in Figs. 4 and 5, respectively. The observed bands with their assignments are listed in Table 4. The bands observed in the region 4000–500 cm1 arise from internal vibrations of L-arginine cations, maleate anions and vibration of hydrogen bonds. To analyze the spectra, we should take into consideration that L-arginine molecule exists in zwitterionic form with typical formula (H2N)2+CNH(CH2)3CH(NH2)COO. Both the a-amino and the guanidyl groups are protonated by accepting proton from its own carboxyl group and maleic acid. Here we can also deduce the results from the IR and Raman spectra. On investigation of the absorption bands below 1000 cm1, COO rocking, COO wagging, C–C stretching and CH2 rocking are identified. In medium wavenumber region (2000–1000 cm1), the presence of COO, NHþ 3 stretching vibration forms an indicator band for zwitterionic structure of L-arginine cation. High wavenumber region (4000–2000 cm1) contains NH2, NHþ 3 , and CH2 stretching vibration and combinations of them. Especially overtones and combination bands of NHþ 3 bending and NHþ torsion confirm the protonation of amino group. 3 However, the intense absorption band at 3226 cm1 are difficult to assign for the overlapping of t(O–H) and t(N–H). Because O–H vibrations of water molecule and hydrogen bonds extend to the region near 3200 cm1 [33,34], while

Fig. 4. IR transmission spectrum.

Fig. 5. Raman spectrum.

N–H occupies a wide range of 3500–3050 cm1 for a large dispersion of hydrogen bonds. Fig. 6 shows the thermal properties of the crystal carried out by TGA and DTA. From these curves, it can be seen that the sample starts losing water from 90 to 105 C with the mass loss of 5.3%. The value is very close to the theoretical share (5.516%) of one water molecule. The evident endothermic peak observed at 99 C in DTA race corresponds to the melting point of the residua. This is attributed to utilization of the thermal energy to overcome the valence bonding between the L-arginine cation and maleate anion, which happens in the initial stage of decomposition. The next loss of mass with endothermic character occurs between 140 and 160 C is due to loss of the rest water. The account for mass loss is about 5.6%, which is nearly same as the theoretical value. The total mass loss of the dehydration is 10.9%, which corresponds to the completed dehydration. During the next stage, maleic acid in the

Z.H. Sun et al. / Optical Materials 30 (2008) 1001–1006 Table 4 Observed spectral data and their assignment in 4000–500 cm1 range IR (cm1) 3408 3226 3041 2959 2670–1700 1682 1625 1514 1489 1391 1360 1347 1311 1210 1169 1123 1042 1010 979 931 894 865 800 747 708 662 581 547 499

Raman shift (cm1)

3042 2971 2926 1685 1627 1481 1438 1394 1364 1343 1314 1210 1172 1048 1013 977 932 889 862 797 754 711 664 579 548 476

Mode assignments N–H  O stretching NH2 stretching; O–H stretching NHþ 3 asymmetric stretching C–H stretching CH2 Stretching Overtone and combination bands C@N stretching COO asymmetric deformation NHþ 3 symmetric deformation C–N asymmetric stretching CH2 deformation COO symmetric deformation C–CH in plane deformation O–H in plane deformation CH2 wagging CH2 twisting C–O(H) stretching NHþ 3 rocking NH2 wagging C–N symmetric stretching O–H out of plane deformation C–C stretching C–C–N symmetric stretching C–C stretching C–C stretching CH2 rocking NH2 out of plane deformation O–C@O in plane deformation COO wagging C–C@O in plane deformation COO rocking

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and amino groups leading to the formation of peptide bonds. More volatile substances, such as CO and CH4 are liberated around 400 C. Further heating results in the liberation of NH3 above 500 C. To check the NLO properties of the grown crystal, Kurtz and Perry technique was used [37]. A high-intensity Nd:YAG laser with fundamental radiation of 1064 nm was used as the optical source and directed onto the powered sample of crystal. The SHG behaviour has been confirmed from the output of intense green light emission (k = 532 nm) from the crystal. Intensity of the bright green emission is three times higher that of KDP. 4. Conclusions In this paper, large-size crystals of L-arginine maleate dihydrate were grown from aqueous solution and its structure was determined by X-ray diffraction. The crystal was characterized using IR and Raman spectra and TGA/ DTA measurements. The NLO properties of the grown crystal were examined by Kurtz and Perry technique, and its SHG efficiency is three times higher that of KDP. Acknowledgements This work is supported by a National Natural Science Foundation of China (NNSFC) Grant (No. 60608010) and a Foundation for the Author of National Excellent Doctoral Dissertation of China (No. 200539). References

Fig. 6. TGA, DTA and DTG curves.

crystal decomposes and may become anhydride [35,36]. Meanwhile, volatile substances are released with further heating. The DTG curve shows these reactions clearly. The loss of mass for this stage is 9.6%. The endothermic peak observed at 310 C in DTG corresponds to formation of peptide. The reactions of simplest amino acids induced by heating include the condensation reactions of carboxyl

[1] D. Xu, M.H. Jiang, Z. Tan, Acta. Chim. Sin. 2 (1983) 230. [2] A. Yokotani, T. Sasaki, K. Yoshida, S. Nakai, Appl. Phys. Lett. 55 (1989) 2692. [3] D. Eimerl, S. Velsko, L. Davis, F. Wang, G. Loiacono, G. Kennedy, IEEE J. Quantum Electron. QE-25 (1989) 179. [4] A.S. H-Hameed, G. Ravi, P. Ramasamy, J. Cryst. Growth 229 (2001) 547. [5] A. Brignnon, J.P. Huignard, Phase Conjugate Laser Optics, John Wiley, 2004. [6] S.S. Terzyan, H.A. Karapetyan, R.B. Sukiasyan, A.M. Petrosyan, J. Cryst. Growth 687 (2004) 111. [7] K. Wu, S.Y. Lee, J. Phys. Chem. A 101 (1997) 937. [8] T. Sasaki, Technol. Rep. Osaka Univ. 39 (1989) 25. [9] H. Yoshida, M. Nakatsuka, H. Fujita, T. Sasaki, K. Yoshida, Appl. Opt. 36 (1997) 7783. [10] S.B. Monaco, L.E. Davis, S.P. Velsko, F.T. Wang, D. Eimerl, A. Zalkin, J. Cryst. Growth 85 (1987) 252. [11] P. Tanusri, K. Tanusree, J. Cryst. Growth 234 (2002) 267. [12] A.M. Petrosyana, H.A. Karapetyan, R.P. Sukiasyana, A.E. Aghajanyan, V.G. Morgunov, E.A. Kravchenko, A.A. Bush, J. Mol. Struct. 752 (2005) 144. [13] T. Pal, T. Kar, J. Cryst. Growth 276 (2005) 247. [14] S. Haussuhl, H.A. Karapetyan, R.P. Sukiasyan, A.M. Petrosyan, Cryst. Growth Des. 6 (2006) 2042. [15] C.G. Suresh, M. Vijayan, Int. J. Peptide Protein Res. 21 (1983) 223. [16] T.N. Bhat, M. Vijayan, Acta Crystallogr. B 33 (1977) 1754. [17] C.G. Suresh, J. Ramaswamy, M. Vijayan, Acta Crystallogr. B 42 (1986) 473. [18] J. Soman, M. Vijayan, J. Biosci. 14 (1989) 111.

1006

Z.H. Sun et al. / Optical Materials 30 (2008) 1001–1006

[19] R. Ravishankar, N.R. Chandra, M. Vijayan, J. Biomed. Struct. Dyn. 15 (1998) 1093. [20] D. Xu, X.Q. Wang, W.T. Yu, S.X. Xu, G.H. Zhang, J. Cryst. Growth 253 (2003) 481. [21] X.J. Liu et al., J. Alloys Compd. (2006), doi:10.1016/ j.jallcom.2006.09.128. [22] Y.L. Geng, D. Xu, X.Q. Wang, G.W. Yu, G.H. Zhang, H.B. Zhang, J. Cryst. Growth 282 (2005) 208. [23] H.L. Bhat, Bull. Mater. Sci. 17 (1994) 1233. [24] G.M. Sheldrick, SHELXS-97, University of Gottingen, Germany, 1997. [25] G.M. Sheldrick, SHELXL-97, University of Gottingen, Germany, 1997. [26] Zefirov, V. Yu, Kristallografia 44 (1999) 1091. [27] H. Ratajczak, J. Baran, S. Debrus, Bull. Pol. Acad. Sci. Chem. 49 (2001) 261.

[28] M.N. James, G.J. Williams, Acta Crystallogr. B30 (1974) 1257. [29] J.C. Barnes, T.J. Weakly, Acta Crystallogr. C53 (1997) IUC9700018. [30] J.V. Pratap, R. Ravishankar, M. Vijayan, Acta Crystallogr. B56 (2000) 690. [31] T.N. Guru Row, Coord. Chem. Rev. 183 (1999) 81. [32] I. Karle, J. Karle, Acta Crystallogr. 17 (1964) 835. [33] K. Nakamoto, M. Margoshes, R.E. Rundle, J. Am. Chem. Soc. 77 (1955) 6480. [34] A. Novak, Infrared and Raman Spectroscopy of biological molecules, in: Proceedings of the NATO Advanced Study Institute, Athens, August 22, 1978. [35] T.R. Felthouse, J.C. Burnett, B. Horrel, M.J. Munney, Y.J. Kuo, www.huntsman.com/performance_products/Media/KOMaleic.pdf. [36] S. Natarajan, S.A. M-Britto, E. Ramachandran, Cryst. Growth Des. 6 (2006) 137. [37] S.K. Kurtz, T.T. Perry, J. Appl. Phys. 39 (1968) 3798.