X-ray, dielectric, piezoelectric and optical analyses of a new nonlinear optical 8-hy­droxy­quinolinium hydrogen squarate crystal

The 1:1 complex of 8-hy­droxy­quinoline with squaric acid has been characterized using single-crystal X-ray diffraction, UV–vis spectroscopy, density functional theory (DFT) calculations, and photoluminescence, dielectric, piezoelectric and second-harmonic generation (SHG) studies. The title compound (8-hy­droxy­quinolinium hydrogen squarate; HQS) contains one protonated 8-hy­droxy­quinoline cation (C₉H₈NO⁺) and one hydrogen squarate mono-anion (C₄HO₄⁻). All the intermolecular hydrogen-bonding interactions present in the HQS crystal structure are analyzed by three-dimensional molecular Hirshfeld surface analysis and their relative contributions are determined from two-dimensional fingerprint plots. The structure of C₉H₈NO⁺·C₄HO₄⁻ molecular complex has been optimized at the DFT/B3LYP/6-31G(d,p) level. The UV–vis spectroscopic data calculated by time-dependent density functional theory are compared with the experimental data. The LUMO+1, LUMO, HOMO and HOMO−1 energy values, their shapes and energy gaps are calculated using the B3LYP/6-31G(d,p) level of theory. The HQS material exhibits high SHG output (2.6 times of that of potassium dihydrogen phosphate), high photoluminescence emission centred at 474 nm and a piezoelectric charge coefficient of 3 pC N⁻¹. Henceforth, HQS can serve as an alternative potential candidate for multifunctional nonlinear optically active and piezoelectric crystals.

Computing details

Data collection: CrysAlis PRO, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58); cell refinement: CrysAlis PRO, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58); data reduction: CrysAlis PRO, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

(I)

Crystal data

C9H8NO·C4HO4	Dx = 1.566 Mg m^−3
Mr = 259.21	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 2142 reflections
a = 5.6052 (3) Å	θ = 3.6–22.1°
b = 8.5753 (4) Å	µ = 0.12 mm^−1
c = 22.881 (1) Å	T = 293 K
V = 1099.81 (9) Å^3	Block, yellow
Z = 4	1.0 × 0.2 × 0.2 mm
F(000) = 536

Data collection

Xcalibur, Sapphire3 diffractometer	2784 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1836 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.062
Detector resolution: 15.9853 pixels mm^-1	θmax = 29.3°, θmin = 3.0°
ω scans	h = −7→7
Absorption correction: multi-scan CrysAlisPro, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	k = −11→10
Tmin = 0.816, Tmax = 1.000	l = −31→31
15943 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.054	w = 1/[σ^2(Fo^2) + (0.033P)^2 + 0.264P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.113	(Δ/σ)max < 0.001
S = 1.04	Δρmax = 0.18 e Å^−3
2784 reflections	Δρmin = −0.24 e Å^−3
174 parameters	Absolute structure: Flack x determined using 529 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
0 restraints	Absolute structure parameter: −0.9 (10)
Primary atom site location: structure-invariant direct methods

Special details

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.

Refinement. 1. Fixed Uiso At 1.2 times of: All C(H) groups, All N(H) groups At 1.5 times of: All O(H) groups 2.a Aromatic/amide H refined with riding coordinates: N1(H1), C7(H7), C2(H2), C4(H4), C5(H5), C3(H3), C6(H6) 2.b Idealised tetrahedral OH refined as rotating group: O4(H4A), O1(H1A)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O2	−0.8725 (4)	−0.9579 (3)	−0.05794 (10)	0.0419 (7)
O5	−1.2637 (4)	−1.1581 (3)	0.01750 (10)	0.0412 (7)
O4	−1.5004 (5)	−1.2779 (4)	−0.10281 (10)	0.0476 (8)
H4A	−1.579042	−1.297145	−0.073470	0.071*
O3	−1.0964 (5)	−1.1035 (3)	−0.17681 (10)	0.0455 (7)
N1	−0.5613 (5)	−0.8385 (3)	−0.14388 (12)	0.0344 (7)
H1	−0.640363	−0.862198	−0.112915	0.041*
C9	−0.3675 (6)	−0.7418 (4)	−0.13843 (14)	0.0305 (8)
O1	−0.4491 (5)	−0.7200 (4)	−0.03865 (11)	0.0530 (8)
H1A	−0.416321	−0.666960	−0.009947	0.079*
C8	−0.3083 (7)	−0.6774 (4)	−0.08400 (15)	0.0352 (9)
C14	−1.2149 (6)	−1.1375 (4)	−0.03536 (15)	0.0319 (8)
C10	−0.2332 (6)	−0.7066 (4)	−0.18893 (14)	0.0310 (8)
C7	−0.1167 (7)	−0.5790 (5)	−0.08069 (16)	0.0430 (10)
H7	−0.074982	−0.535064	−0.044974	0.052*
C2	−0.6321 (7)	−0.8968 (5)	−0.19418 (16)	0.0401 (9)
H2	−0.765613	−0.960975	−0.195677	0.048*
C12	−1.1411 (6)	−1.1142 (4)	−0.12425 (15)	0.0327 (8)
C4	−0.3094 (7)	−0.7709 (4)	−0.24232 (15)	0.0398 (9)
H4	−0.223167	−0.750631	−0.276204	0.048*
C11	−1.0364 (6)	−1.0510 (4)	−0.06933 (14)	0.0316 (8)
C13	−1.3175 (6)	−1.1911 (4)	−0.08866 (15)	0.0329 (8)
C5	−0.0366 (7)	−0.6060 (4)	−0.18359 (16)	0.0403 (9)
H5	0.056103	−0.581947	−0.216071	0.048*
C3	−0.5073 (8)	−0.8624 (4)	−0.24510 (17)	0.0424 (10)
H3	−0.558844	−0.901651	−0.280815	0.051*
C6	0.0167 (7)	−0.5441 (5)	−0.13051 (16)	0.0433 (10)
H6	0.145829	−0.476590	−0.127269	0.052*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0471 (15)	0.0487 (16)	0.0298 (13)	−0.0107 (14)	0.0024 (13)	−0.0065 (12)
O5	0.0366 (14)	0.0658 (19)	0.0212 (13)	0.0024 (13)	0.0019 (12)	0.0040 (11)
O4	0.0437 (15)	0.072 (2)	0.0270 (13)	−0.0186 (15)	0.0040 (12)	−0.0055 (14)
O3	0.0498 (16)	0.0642 (19)	0.0223 (13)	−0.0108 (15)	0.0058 (12)	−0.0006 (13)
N1	0.0361 (17)	0.0385 (18)	0.0286 (16)	−0.0025 (15)	0.0019 (14)	−0.0009 (13)
C9	0.0336 (18)	0.0302 (19)	0.0278 (18)	0.0008 (16)	−0.0030 (16)	0.0000 (15)
O1	0.0634 (19)	0.067 (2)	0.0285 (14)	−0.0166 (16)	0.0080 (14)	−0.0085 (14)
C8	0.042 (2)	0.036 (2)	0.0273 (19)	0.0014 (17)	−0.0026 (17)	−0.0005 (16)
C14	0.0296 (19)	0.039 (2)	0.0271 (18)	0.0050 (16)	0.0018 (16)	0.0000 (16)
C10	0.0353 (19)	0.0297 (19)	0.0279 (18)	0.0010 (16)	−0.0013 (17)	0.0021 (15)
C7	0.049 (2)	0.048 (2)	0.031 (2)	−0.004 (2)	−0.0074 (19)	−0.0059 (18)
C2	0.042 (2)	0.041 (2)	0.038 (2)	−0.0067 (18)	−0.0037 (19)	−0.0032 (18)
C12	0.035 (2)	0.037 (2)	0.0260 (18)	0.0028 (17)	0.0009 (17)	0.0004 (16)
C4	0.049 (2)	0.040 (2)	0.0301 (19)	−0.0049 (19)	0.0054 (18)	0.0025 (17)
C11	0.035 (2)	0.035 (2)	0.0255 (18)	0.0047 (18)	0.0003 (16)	−0.0010 (16)
C13	0.0299 (19)	0.042 (2)	0.0271 (19)	0.0017 (17)	0.0007 (16)	−0.0020 (16)
C5	0.041 (2)	0.044 (2)	0.036 (2)	−0.0077 (19)	0.0027 (19)	0.0021 (19)
C3	0.052 (2)	0.045 (2)	0.030 (2)	−0.008 (2)	−0.0025 (19)	−0.0043 (17)
C6	0.040 (2)	0.046 (2)	0.044 (2)	−0.009 (2)	−0.002 (2)	0.001 (2)

Geometric parameters (Å, º)

O2—C11	1.244 (4)	C14—C13	1.425 (5)
O5—C14	1.252 (4)	C10—C4	1.407 (4)
O4—C13	1.308 (4)	C10—C5	1.405 (5)
O3—C12	1.232 (4)	C7—C6	1.396 (5)
N1—C9	1.372 (4)	C2—C3	1.390 (5)
N1—C2	1.316 (4)	C12—C11	1.489 (5)
C9—C8	1.402 (4)	C12—C13	1.441 (5)
C9—C10	1.412 (4)	C4—C3	1.360 (5)
O1—C8	1.354 (4)	C11—C13	2.030 (5)
C8—C7	1.368 (5)	C5—C6	1.359 (5)
C14—C11	1.469 (5)
C2—N1—C9	123.2 (3)	C13—C12—C11	87.7 (3)
N1—C9—C8	120.4 (3)	C3—C4—C10	120.9 (3)
N1—C9—C10	118.5 (3)	O2—C11—C14	135.7 (3)
C8—C9—C10	121.1 (3)	O2—C11—C12	134.5 (3)
O1—C8—C9	115.9 (3)	O2—C11—C13	176.4 (3)
O1—C8—C7	125.6 (3)	C14—C11—C12	89.7 (3)
C7—C8—C9	118.6 (3)	C14—C11—C13	44.55 (19)
O5—C14—C11	137.0 (3)	C12—C11—C13	45.15 (19)
O5—C14—C13	133.9 (3)	O4—C13—C14	135.4 (3)
C13—C14—C11	89.1 (3)	O4—C13—C12	131.2 (3)
C4—C10—C9	117.7 (3)	O4—C13—C11	177.8 (3)
C5—C10—C9	118.6 (3)	C14—C13—C12	93.4 (3)
C5—C10—C4	123.7 (3)	C14—C13—C11	46.32 (19)
C8—C7—C6	120.5 (4)	C12—C13—C11	47.12 (19)
N1—C2—C3	120.1 (4)	C6—C5—C10	119.3 (3)
O3—C12—C11	135.8 (3)	C4—C3—C2	119.6 (4)
O3—C12—C13	136.5 (3)	C5—C6—C7	121.9 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2	0.86	1.99	2.821 (4)	163
N1—H1···O1	0.86	2.35	2.688 (4)	104
C2—H2···O3	0.93	2.26	3.174 (5)	167
C7—H7···O2^i	0.93	2.89	3.495	124
C7—H7···O1^i	0.93	2.93	3.363	110
C7—H7···O5^ii	0.93	2.49	3.185	132 (5)
C6—H6···O5^ii	0.93	2.81	3.348	118
C5—H5···O3^iii	0.93	2.47	3.280 (4)	146
C4—H4···O3^iii	0.93	2.44	3.265 (5)	148
C3—H3···O4^iv	0.93	2.89	3.555	130
C6—H6···O4^v	0.93	2.67	3.597	172
O4—H4A···O5	0.82	2.98	3.224	100
O4—H4A···O5^vi	0.82	1.69	2.508 (5)	174
O1—H1A···O2^i	0.82	1.90	2.720 (4)	174

Symmetry codes: (i) x+1/2, −y−3/2, −z; (ii) x+3/2, −y−3/2, −z; (iii) −x−1, y+1/2, −z−1/2; (iv) −x−2, y+1/2, −z−1/2; (v) x+2, y+1, z; (vi) x−1/2, −y−5/2, −z.