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Crystal structure of 2-ethyl-4-methyl-1-(2-oxido-3,4-dioxo­cyclo­but-1-en-1-yl)-1H-imidazol-3-ium

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aOndokuz Mayis University, Faculty of Arts and Sciences, Department of Physics, Atakum, Samsun, Turkey, and bOndokuz Mayis University, Faculty of Arts and Sciences, Department of Chemistry, Atakum, Samsun, Turkey
*Correspondence e-mail: iclalb@omu.edu.tr

Edited by D.-J. Xu, Zhejiang University (Yuquan Campus), China (Received 30 May 2016; accepted 15 June 2016; online 21 June 2016)

In the title inner salt molecule, C10H10N2O3, the four-membered cyclobutene ring is twisted by 7.1 (2)° with respect to the five-membered imidazole ring. The crystal packing exhibits an R22(9) hydrogen-bonding ring motif through N—H⋯O and C—H⋯O inter­actions. The potential non-linear optical properties were studied by a computational ab initio calculations performed at the DFT/B3LYP/6–31++G(d,p) level of theory.

1. Chemical context

The study of the non-linear optical (NLO) properties of organic mol­ecules and crystals are of great inter­est in physics, chemistry and applied technologies (Chemla et al., 1987[Chemla, D. S. & Zyss, J. (1987). In Nonlinear Optical Properties of Organic Molecules and Crystals. New York: Academic Press.]). Certain classes of organic compounds exhibit very pronounced NLO and electro-optical (EO) effects. Their non-linearity is based on the presence of mol­ecular units containing strongly delocalized π-electron systems with the donor and acceptor groups sited at opposite ends of the mol­ecule (Bosshard et al., 1995[Bosshard, C., Sutter, K., Prêtre, P., Hulliger, J., Flörsheimer, M., Kaatz, P. & Günter, P. (1995). In Organic Nonlinear Optical Materials. Amsterdam: Gordon & Breach.]; Kolev et al., 2008[Kolev, T. M., Yancheva, D. Y., Stamboliyska, B. A., Dimitrov, M. D. & Wortmann, R. (2008). Chem. Phys. 348, 45-52.]). The study of the development of new non-centrosymmetric single-crystal NLO materials to obtain efficient frequency doublers is the subject of crystal engineering. In this context, some squaric acid derivatives together with cyclo­butenediones with proper substitution groups have been found to be of inter­est in terms of their high NLO responses (Kolev et al., 2008[Kolev, T. M., Yancheva, D. Y., Stamboliyska, B. A., Dimitrov, M. D. & Wortmann, R. (2008). Chem. Phys. 348, 45-52.]).

[Scheme 1]

Squaric acid gives rise to two structurally different classes of derivatives, which can be described by the general mol­ecular structures 1,3-N-squarenes and amine-containing mol­ecule betaines (Gsänger et al., 2014[Gsänger, M., Kirchner, E., Stolte, M., Burschka, C., Stepanenko, V., Pflaum, J. & Würthner, F. J. (2014). J. Am. Chem. Soc. 136, 2351-2362.]; Kolev et al., 2005[Kolev, T., Wortmann, R., Spiteller, M., Sheldrick, W. S. & Mayer-Figge, H. (2005). Acta Cryst. E61, o1090-o1092.]). The squarenes shows photo-chemical, photo-conductive and NLO properties and can therefore be used as electron acceptors in photo-sensitive devices (Lindsay & Singer, 1995[Lindsay, G. A. & Singer, K. D. (1995). Editors. Polymers for Second-Order Nonlinear Optics, ACS Symposium Series 601.]). On the other hand, substituted betaines play an important role in NLO behavior due to their dipolar structures (Kolev et al., 2004[Kolev, T. M., Stamboliyska, B. A., Yancheva, D. Y. & Enchev, V. J. (2004). J. Mol. Struct. 691, 241-248.]). The conversion of the N2 atom of 2-ethyl-4-methyl­imidazole into the corresponding betaine squaric acid form provides a way of enhancing the charge-transfer transition at the mol­ecular level.

This study reports a novel betain form of squaric acid with a 2-ethyl-4-methyl­imidazole mol­ecule. The crystal structure, together with its NLO properties, are reported here.

2. Structural commentary

A view of the asymmetric unit is given in Fig. 1[link]. The C1—C2—C3, C2—C1—C4 and C2—C3—C4 bond angles in the squarate ring system are almost 90°. The C1—C4—C3 bond angle is 95.0 (3)° due to the C4 atom bonding to the imidazole ring through N2 atom. The C—C distances in the planar squarate ring system of the compound reflect partial double-bond character for C1—C4 and C3—C4 [1.426 (4) and 1.440 (4) Å, respectively]. Single-bond character is observed for C1—C2 and C2—C3 [1.514 (5) and 1.516 (5) Å, respectively]. The observed bond lengths indicate a degree of delocalization in the squarate ring, as has been observed in previous studies (Kolev et al., 2005[Kolev, T., Wortmann, R., Spiteller, M., Sheldrick, W. S. & Mayer-Figge, H. (2005). Acta Cryst. E61, o1090-o1092.]; Korkmaz et al., 2013[Korkmaz, U. & Bulut, A. (2013). J. Mol. Struct. 1050, 61-68.]). The C1—O1 and C3—O3 bond lengths are 1.234 (4) and 1.216 (4) Å, respectively. Conjugation of the squarate ring and the positively charged strong acceptor N2 result in a shortening of the carbonyl group C2=O2 bond [1.206 (4) Å]. A strong donor effect is observed for the 2-ethyl-4-methyl­imidazole group.

[Figure 1]
Figure 1
A view of the molecular structure of the title inner salt, with the atom labelling. Displacement ellipsoids drawn at the 40% probability level.

3. Supra­molecular features

The structural properties of the mol­ecule are the result of an extensive network of hydrogen-bonding inter­actions. The N—H⋯O and C—H⋯O heteronuclear hydrogen bonds that form an [R_{2}^{2}](9) ring motif contribute as both donor and acceptor to the crystal packing (Table 1[link], Fig. 2[link]). The N⋯O distance should be in the region of 2.72–2.78 Å, The observed N1—H1⋯O1i DA distance [2.680 (3) Å; Table 1[link]] corres­ponds to a [(+/−)CAHB] inter­action. Looking at the N⋯O distances in the symmetry-related hydrogen bonding between squarate ring systems, it can be seen that the inter­action is slightly shorter than the relevant inter­val values and is symbolized as either N+—H⋯ O1\2− or N+—H⋯ O (+/−)CAHB (Korkmaz & Bulut, 2013[Korkmaz, U. & Bulut, A. (2013). J. Mol. Struct. 1050, 61-68.]). The C—H⋯O (Table 1[link], Fig. 2[link]) inter­actions correspond to weak hydrogen bonding with an electrostatic or dispersion character according to the classification of Jeffrey (1997[Jeffrey, G. A. (1997). In An Introduction to Hydrogen Bonding. New York: Oxford University Press Inc.]). In the structure, the weak C—H⋯O inter­actions are responsible for the connection between the ribbons. Therefore it can be said that the hydrogen bonds form the mol­ecular assembly, producing a uni-dimensional construction in the supra­molecular view, while the C—H⋯O inter­actions extend this to bi-dimensionality.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O1i 0.97 (4) 1.73 (4) 2.680 (3) 164 (3)
C6—H6A⋯O1i 0.96 2.59 3.378 (4) 139
C9—H9A⋯O1 0.97 2.35 3.112 (4) 135
C9—H9B⋯O2i 0.97 2.51 3.429 (5) 158
Symmetry code: (i) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].
[Figure 2]
Figure 2
The crystal packing of the title compound, illustrating the N—H⋯O hydrogen bonds in the [010] direction together with weak C—H⋯O hydrogen bonds.

4. Computational studies

We have applied computational methods to evaluate the compound in terms of NLO activity. The values of the dipole moment (μtot), linear polarizability (αtot) and first-order hyperpolarizability (βtot) of the mol­ecule were calculated at the DFT/B3LYP method level of 6-31++G(d,p) by using Gaussian 03W program (Frisch et al., 2004[Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., Montgomery, J. A., Vreven, T., Kudin, K. N., Burant, J. C., Millam, J. M., Iyengar, S. S., Tomasi, J., Barone, V., Mennucci, B., Cossi, M., Scalmani, G., Rega, N., Petersson, G. A., Nakatsuji, H., Hada, M., Ehara, M., Toyota, K., Fukuda, R., Hasegawa, J., Ishida, M., Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Klene, M., Li, X., Knox, J. E., Hratchian, H. P., Cross, J. B., Bakken, V., Adamo, C., Jaramillo, J., Gomperts, R., Stratmann, R. E., Yazyev, O., Austin, A. J., Cammi, R., Pomelli, C., Ochterski, J. W., Ayala, P. Y., Morokuma, K., Voth, G. A., Salvador, P., Dannenberg, J. J., Zakrzewski, V. G., Dapprich, S., Daniels, A. D., Strain, M. C., Farkas, O., Malick, D. K., Rabuck, A. D., Raghavachari, K., Foresman, J. B., Ortiz, J. V., Cui, Q., Baboul, A. G., Clifford, S., Cioslowski, J., Stefanov, B. B., Liu, G., Liashenko, A., Piskorz, P., Komaromi, I., Martin, R. L., Fox, D. J., Keith, T., Al-Laham, M. A., Peng, C. Y., Nanayakkara, A., Challacombe, M., Gill, P. M. W., Johnson, B., Chen, W., Wong, M. W., Gonzalez, C. & Pople, J. A. (2004). GAUSSIAN03. Gaussian Inc., Wallingford, CT, USA.]). Urea is accepted as a prototype mol­ecule for non-linear optical materials and results were compared with its values (Pu, 1991[Pu, L. S. (1991). Acs Symp. Ser. 455, 331-343.]). The calculation results for μtot, αtot and βtot for urea at the same level are 3.8583 D, 4.9991 Å3 and 3.2637 x 10−31cm5/esu, respectively. The obtained values of μtot, αtot and βtot for the title compound are 14.8448 D, 22.2315 Å3 and 6.8664 × 10−30 cm5/esu, respectively. These values are comparable with those for some of the pyridinium-betains of squaric acid (Kolev et al., 2008[Kolev, T. M., Yancheva, D. Y., Stamboliyska, B. A., Dimitrov, M. D. & Wortmann, R. (2008). Chem. Phys. 348, 45-52.]). The value of βtot appears to be much greater than that of urea. This result clearly indicates that the title compound is a strong candidate to develop a non-linear optical material. This is a prerequisite for the design of efficient second- and third-order non-linear optical materials. It should be noted that the title compound crystallized in a centrosymmetric space group (P21/n).

5. Synthesis and crystallization

The title compound was synthesized according to the procedure of Schmidt et al. (1984[Schmidt, A. H., Becker, U. & Aiméne, A. (1984). Tetrahedron Lett. 25, 4475-4478.]). Squaric acid (H2Sq; 1g, 8.7 mmol) and 2-ethyl-4-methyl­imidazole (0.96 g; 8.7 mmol) were dissolved in acetic anhydride (30 cm3) in the molar ratio 1:1 and the solution was heated to 323 K using a controlled bath and stirred for 1 h. The reaction mixture was then cooled slowly to room temperature. The crystals formed were filtered, washed with water and methanol, and dried in air. A few days later, well-formed crystals were selected for X-ray studies. Elemental analysis for the compound (green, yield 48%) C10H10N2O3: calculated: C, 58.00; H, 5.11; N, 13.56%. Found: C, 58.25; H, 4.89; N, 13.59%. M.p. 544 K.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The H atoms attached to C5 and N1 (H5 and H1, respectively) were located in Fourier difference maps and freely refined. The remaining H atoms were positioned geometrically (C—H = 0.96–0.97 Å) and refined using a riding model with Uiso(H) = 1.2 or 1.5Ueq(C).

Table 2
Experimental details

Crystal data
Chemical formula C10H10N2O3
Mr 206.20
Crystal system, space group Monoclinic, P21/n
Temperature (K) 293
a, b, c (Å) 4.7940 (4), 14.4120 (9), 14.5360 (9)
β (°) 93.848 (6)
V3) 1002.04 (12)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.10
Crystal size (mm) 0.34 × 0.22 × 0.22
 
Data collection
Diffractometer Agilent SuperNova (single source at offset) Eos
Absorption correction Multi-scan (CrysAlis PRO; Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.])
Tmin, Tmax 0.708, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 5496, 3048, 1363
Rint 0.048
(sin θ/λ)max−1) 0.714
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.080, 0.247, 1.04
No. of reflections 3048
No. of parameters 144
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.33, −0.35
Computer programs: CrysAlis PRO (Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]) and DIAMOND (Brandenburg, 2005[Brandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]).

Supporting information


Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

2-Ethyl-4-methyl-1-(2-oxido-3,4-dioxocyclobut-1-en-1-yl)-1H-imidazol-3-ium top
Crystal data top
C10H10N2O3Dx = 1.367 Mg m3
Mr = 206.20Melting point: 544 K
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 4.7940 (4) ÅCell parameters from 943 reflections
b = 14.4120 (9) Åθ = 4.0–30.4°
c = 14.5360 (9) ŵ = 0.10 mm1
β = 93.848 (6)°T = 293 K
V = 1002.04 (12) Å3Prism, green
Z = 40.34 × 0.22 × 0.22 mm
F(000) = 432
Data collection top
Agilent SuperNova (single source at offset) Eos
diffractometer
3048 independent reflections
Radiation source: SuperNova (Mo) X-ray Source1363 reflections with I > 2σ(I)
Detector resolution: 16.0454 pixels mm-1Rint = 0.048
ω scansθmax = 30.5°, θmin = 4.0°
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
h = 66
Tmin = 0.708, Tmax = 1.000k = 1620
5496 measured reflectionsl = 2011
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.080H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.247 w = 1/[σ2(Fo2) + (0.0793P)2 + 0.493P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
3048 reflectionsΔρmax = 0.33 e Å3
144 parametersΔρmin = 0.35 e Å3
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
H50.783 (8)0.546 (3)0.562 (2)0.060 (11)*
H10.312 (8)0.693 (3)0.724 (2)0.069 (12)*
O10.2719 (5)0.30379 (16)0.74162 (16)0.0548 (7)
N10.3883 (6)0.63979 (19)0.69274 (18)0.0419 (6)
N20.5210 (5)0.50284 (17)0.65685 (16)0.0382 (6)
O30.9453 (5)0.38166 (18)0.54799 (18)0.0614 (7)
C40.5674 (6)0.4072 (2)0.6522 (2)0.0375 (7)
C30.7687 (7)0.3595 (2)0.6001 (2)0.0432 (8)
O20.7096 (6)0.18740 (16)0.63047 (19)0.0675 (8)
C20.6603 (7)0.2691 (2)0.6374 (2)0.0454 (8)
C80.3574 (6)0.5506 (2)0.7126 (2)0.0393 (7)
C10.4553 (7)0.3249 (2)0.6897 (2)0.0409 (7)
C50.6580 (7)0.5660 (2)0.6024 (2)0.0415 (7)
C60.6446 (9)0.7446 (2)0.5893 (2)0.0590 (10)
H6A0.54460.79120.62100.089*
H6B0.84200.75510.59980.089*
H6C0.59320.74790.52440.089*
C90.1873 (8)0.5129 (2)0.7852 (2)0.0512 (9)
H9A0.10380.45470.76410.061*
H9B0.03690.55590.79550.061*
C70.5737 (7)0.6514 (2)0.6245 (2)0.0430 (8)
C100.3587 (12)0.4966 (3)0.8760 (3)0.0884 (16)
H10A0.23980.47230.92080.133*
H10B0.50560.45310.86650.133*
H10C0.43870.55430.89790.133*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0629 (16)0.0385 (13)0.0661 (15)0.0065 (11)0.0278 (13)0.0052 (11)
N10.0482 (16)0.0340 (14)0.0439 (14)0.0004 (12)0.0053 (12)0.0031 (11)
N20.0423 (15)0.0330 (13)0.0404 (12)0.0001 (11)0.0110 (11)0.0004 (10)
O30.0610 (17)0.0521 (15)0.0753 (17)0.0066 (13)0.0351 (14)0.0089 (13)
C40.0394 (16)0.0330 (16)0.0405 (15)0.0005 (13)0.0057 (13)0.0015 (12)
C30.0439 (18)0.0396 (18)0.0474 (17)0.0035 (14)0.0118 (14)0.0021 (14)
O20.0790 (19)0.0345 (14)0.0906 (19)0.0097 (13)0.0179 (15)0.0010 (13)
C20.0479 (19)0.0380 (18)0.0511 (18)0.0041 (15)0.0089 (15)0.0028 (14)
C80.0377 (16)0.0379 (17)0.0426 (15)0.0001 (13)0.0057 (13)0.0020 (13)
C10.0448 (18)0.0337 (16)0.0447 (16)0.0004 (13)0.0074 (14)0.0013 (13)
C50.0475 (19)0.0337 (17)0.0446 (16)0.0016 (14)0.0128 (15)0.0027 (13)
C60.081 (3)0.038 (2)0.060 (2)0.0057 (18)0.018 (2)0.0014 (16)
C90.055 (2)0.0435 (19)0.058 (2)0.0025 (16)0.0230 (17)0.0024 (16)
C70.0524 (19)0.0368 (17)0.0403 (15)0.0042 (15)0.0062 (14)0.0006 (13)
C100.128 (5)0.089 (3)0.049 (2)0.035 (3)0.012 (2)0.010 (2)
Geometric parameters (Å, º) top
C1—O11.234 (4)C8—C91.479 (4)
N1—C81.328 (4)C5—C71.341 (4)
N1—C71.386 (4)C5—H50.91 (4)
N1—H10.97 (4)C6—C71.485 (5)
C8—N21.353 (4)C6—H6A0.9600
N2—C51.399 (4)C6—H6B0.9600
C4—N21.399 (4)C6—H6C0.9600
C3—O31.216 (4)C9—C101.526 (5)
C1—C41.426 (4)C9—H9A0.9700
C3—C41.440 (4)C9—H9B0.9700
C2—C31.516 (5)C10—H10A0.9600
C2—O21.206 (4)C10—H10B0.9600
C1—C21.514 (5)C10—H10C0.9600
C8—N1—C7111.0 (3)N2—C5—H5121 (2)
C8—N1—H1127 (2)C7—C6—H6A109.5
C7—N1—H1121 (2)C7—C6—H6B109.5
C8—N2—C5108.7 (3)H6A—C6—H6B109.5
C8—N2—C4129.1 (3)C7—C6—H6C109.5
C5—N2—C4122.1 (3)H6A—C6—H6C109.5
N2—C4—C1137.4 (3)H6B—C6—H6C109.5
N2—C4—C3127.6 (3)C8—C9—C10112.5 (3)
C1—C4—C395.0 (3)C8—C9—H9A109.1
O3—C3—C4136.1 (3)C10—C9—H9A109.1
O3—C3—C2135.9 (3)C8—C9—H9B109.1
C2—C3—C488.0 (2)C10—C9—H9B109.1
O2—C2—C1134.2 (3)H9A—C9—H9B107.8
O2—C2—C3137.3 (3)C5—C7—N1106.2 (3)
C1—C2—C388.5 (2)C5—C7—C6131.9 (3)
N1—C8—N2106.5 (3)N1—C7—C6121.9 (3)
N1—C8—C9125.8 (3)C9—C10—H10A109.5
N2—C8—C9127.6 (3)C9—C10—H10B109.5
O1—C1—C4137.8 (3)H10A—C10—H10B109.5
O1—C1—C2133.6 (3)C9—C10—H10C109.5
C2—C1—C488.6 (2)H10A—C10—H10C109.5
C7—C5—N2107.6 (3)H10B—C10—H10C109.5
C7—C5—H5132 (2)
C8—N2—C4—C18.9 (6)C4—N2—C8—C91.3 (5)
C5—N2—C4—C1173.9 (3)N2—C4—C1—O10.0 (7)
C8—N2—C4—C3171.7 (3)C3—C4—C1—O1179.5 (4)
C5—N2—C4—C35.6 (5)N2—C4—C1—C2179.6 (4)
N2—C4—C3—O30.7 (6)C3—C4—C1—C20.0 (3)
C1—C4—C3—O3178.9 (4)O2—C2—C1—O10.6 (7)
N2—C4—C3—C2179.7 (3)C3—C2—C1—O1179.6 (4)
C1—C4—C3—C20.0 (3)O2—C2—C1—C4179.8 (4)
O3—C3—C2—O21.2 (7)C3—C2—C1—C40.0 (2)
C4—C3—C2—O2179.8 (4)C8—N2—C5—C70.9 (4)
O3—C3—C2—C1179.0 (4)C4—N2—C5—C7178.6 (3)
C4—C3—C2—C10.0 (2)N1—C8—C9—C1093.9 (4)
C7—N1—C8—N20.5 (3)N2—C8—C9—C1082.6 (4)
C7—N1—C8—C9176.7 (3)N2—C5—C7—N10.5 (4)
C5—N2—C8—N10.8 (3)N2—C5—C7—C6179.3 (3)
C4—N2—C8—N1178.3 (3)C8—N1—C7—C50.1 (4)
C5—N2—C8—C9176.3 (3)C8—N1—C7—C6179.8 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.97 (4)1.73 (4)2.680 (3)164 (3)
C6—H6A···O1i0.962.593.378 (4)139
C9—H9A···O10.972.353.112 (4)135
C9—H9B···O2i0.972.513.429 (5)158
Symmetry code: (i) x+1/2, y+1/2, z+3/2.
 

Acknowledgements

We would like thank the Ondokuz Mayıs University Research Fund (PYO·FEN.1904.12.020) for financial support and also Dr Murat Taş for collecting the XRD data.

References

First citationAgilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.  Google Scholar
First citationBosshard, C., Sutter, K., Prêtre, P., Hulliger, J., Flörsheimer, M., Kaatz, P. & Günter, P. (1995). In Organic Nonlinear Optical Materials. Amsterdam: Gordon & Breach.  Google Scholar
First citationBrandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationChemla, D. S. & Zyss, J. (1987). In Nonlinear Optical Properties of Organic Molecules and Crystals. New York: Academic Press.  Google Scholar
First citationFrisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., Montgomery, J. A., Vreven, T., Kudin, K. N., Burant, J. C., Millam, J. M., Iyengar, S. S., Tomasi, J., Barone, V., Mennucci, B., Cossi, M., Scalmani, G., Rega, N., Petersson, G. A., Nakatsuji, H., Hada, M., Ehara, M., Toyota, K., Fukuda, R., Hasegawa, J., Ishida, M., Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Klene, M., Li, X., Knox, J. E., Hratchian, H. P., Cross, J. B., Bakken, V., Adamo, C., Jaramillo, J., Gomperts, R., Stratmann, R. E., Yazyev, O., Austin, A. J., Cammi, R., Pomelli, C., Ochterski, J. W., Ayala, P. Y., Morokuma, K., Voth, G. A., Salvador, P., Dannenberg, J. J., Zakrzewski, V. G., Dapprich, S., Daniels, A. D., Strain, M. C., Farkas, O., Malick, D. K., Rabuck, A. D., Raghavachari, K., Foresman, J. B., Ortiz, J. V., Cui, Q., Baboul, A. G., Clifford, S., Cioslowski, J., Stefanov, B. B., Liu, G., Liashenko, A., Piskorz, P., Komaromi, I., Martin, R. L., Fox, D. J., Keith, T., Al-Laham, M. A., Peng, C. Y., Nanayakkara, A., Challacombe, M., Gill, P. M. W., Johnson, B., Chen, W., Wong, M. W., Gonzalez, C. & Pople, J. A. (2004). GAUSSIAN03. Gaussian Inc., Wallingford, CT, USA.  Google Scholar
First citationGsänger, M., Kirchner, E., Stolte, M., Burschka, C., Stepanenko, V., Pflaum, J. & Würthner, F. J. (2014). J. Am. Chem. Soc. 136, 2351–2362.  PubMed Google Scholar
First citationJeffrey, G. A. (1997). In An Introduction to Hydrogen Bonding. New York: Oxford University Press Inc.  Google Scholar
First citationKolev, T. M., Stamboliyska, B. A., Yancheva, D. Y. & Enchev, V. J. (2004). J. Mol. Struct. 691, 241–248.  CrossRef CAS Google Scholar
First citationKolev, T., Wortmann, R., Spiteller, M., Sheldrick, W. S. & Mayer-Figge, H. (2005). Acta Cryst. E61, o1090–o1092.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationKolev, T. M., Yancheva, D. Y., Stamboliyska, B. A., Dimitrov, M. D. & Wortmann, R. (2008). Chem. Phys. 348, 45–52.  CrossRef CAS Google Scholar
First citationKorkmaz, U. & Bulut, A. (2013). J. Mol. Struct. 1050, 61–68.  CSD CrossRef CAS Google Scholar
First citationLindsay, G. A. & Singer, K. D. (1995). Editors. Polymers for Second-Order Nonlinear Optics, ACS Symposium Series 601.  Google Scholar
First citationPu, L. S. (1991). Acs Symp. Ser. 455, 331–343.  CrossRef CAS Google Scholar
First citationSchmidt, A. H., Becker, U. & Aiméne, A. (1984). Tetrahedron Lett. 25, 4475–4478.  CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

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