Growth, crystal structure, Hirshfeld surface, optical, piezoelectric, dielectric and mechanical properties of bis­(L-asparaginium hydrogensquarate) single crystal

Molecular organic single crystals of bis­(L-asparaginium hydrogensquarate) monohydrate [BASQ; (C₈H₁₀N₂O₇)₂·H₂O] have been grown by solution technique. Crystallographic information was investigated by single-crystal X-ray diffraction (SCXRD) analysis. Hirshfeld surface and fingerprint plot studies were performed to understand the intermolecular interactions of the BASQ crystal in graphical representation. Functional group identification was studied with FT–IR (Fourier transform–IR) spectroscopy. The positions of proton and carbon atoms in the BASQ compound were analyzed using NMR spectroscopy. High transparency and a wide band gap of 3.49 eV were observed in the linear optical study by UV–vis–NIR spectroscopy. Intense and broad photoluminescence emissions at room temperature were observed in blue and blue–green regions. The frontier molecular orbitals of the BASQ molecule were obtained by the DFT/B3LYP method employing 6-311G** as the basis set. The dielectric study was carried out with temperature at various frequency ranges. The piezoelectric charge coefficient (d₃₃) value of BASQ crystal was found to be 2 pC/N, which leads to its application in energy harvesting, mechanical sensors and actuators applications. In the non-linear optical study, the BASQ crystal showed promising SHG conversion efficiency. Mechanical properties of the BASQ crystal were studied experimentally by Vicker's microhardness technique, which revealed that the grown crystal belonged to the softer category. BASQ crystal void estimation reveals the mechanical strength and porosity of the material.

Computing details

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

2(C4H9N2O3)·2(C4HO4)·H2O	Dx = 1.574 Mg m^−3
Mr = 510.38	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P21212	Cell parameters from 2347 reflections
a = 19.7808 (13) Å	θ = 3.4–29.2°
b = 8.9659 (6) Å	µ = 0.14 mm^−1
c = 6.0713 (4) Å	T = 293 K
V = 1076.75 (12) Å^3	Block, colorless
Z = 2	0.5 × 0.5 × 0.5 mm
F(000) = 532

Data collection

Xcalibur, Sapphire3 diffractometer	2394 reflections with I > 2σ(I)
ω scans	Rint = 0.019
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.	θmax = 29.2°, θmin = 3.4°
Tmin = 0.850, Tmax = 1.000	h = −24→26
5216 measured reflections	k = −11→4
2531 independent reflections	l = −7→7

Refinement

Refinement on F^2	H atoms treated by a mixture of independent and constrained refinement
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.041P)^2 + 0.176P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.035	(Δ/σ)max = 0.001
wR(F^2) = 0.086	Δρmax = 0.26 e Å^−3
S = 1.09	Δρmin = −0.16 e Å^−3
2531 reflections	Extinction correction: SHELXL-2014/7 (Sheldrick 2014, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
167 parameters	Extinction coefficient: 0.018 (4)
0 restraints	Absolute structure: Flack x determined using 882 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.1 (4)
Hydrogen site location: mixed

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.

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

	x	y	z	Uiso*/Ueq
O4	−0.44943 (9)	−0.83943 (18)	−0.4070 (2)	0.0354 (4)
O2	−0.39987 (11)	−1.0128 (2)	0.2833 (3)	0.0452 (5)
H2	−0.4133	−0.9544	0.3776	0.068*
O1	−0.47779 (8)	−0.72246 (18)	0.0954 (3)	0.0338 (4)
O3	−0.36888 (9)	−1.12265 (19)	−0.2132 (3)	0.0378 (4)
C1	−0.44708 (10)	−0.8293 (2)	0.0092 (3)	0.0235 (4)
C4	−0.43391 (11)	−0.8815 (2)	−0.2203 (3)	0.0240 (4)
C2	−0.41196 (11)	−0.9579 (2)	0.0882 (3)	0.0270 (4)
C3	−0.39708 (11)	−1.0131 (2)	−0.1306 (3)	0.0254 (4)
O5	−0.34959 (8)	−0.55773 (19)	−0.3119 (3)	0.0328 (4)
N1	−0.42409 (9)	−0.3422 (2)	−0.5022 (3)	0.0277 (4)
H1A	−0.4548	−0.2909	−0.5778	0.033*
H1B	−0.3926	−0.2801	−0.4516	0.033*
H1C	−0.4440	−0.3881	−0.3896	0.033*
C5	−0.34832 (10)	−0.5579 (2)	−0.5101 (3)	0.0243 (4)
O7	−0.27338 (8)	−0.3096 (2)	−0.5702 (3)	0.0388 (4)
C6	−0.39223 (10)	−0.4543 (2)	−0.6481 (3)	0.0223 (4)
H6	−0.4286	−0.5147	−0.7115	0.027*
O6	−0.31313 (9)	−0.6483 (2)	−0.6345 (3)	0.0362 (4)
H6A	−0.2883	−0.6994	−0.5569	0.054*
C8	−0.29175 (11)	−0.3008 (3)	−0.7648 (4)	0.0284 (5)
C7	−0.35520 (10)	−0.3801 (3)	−0.8382 (3)	0.0276 (4)
H7A	−0.3434	−0.4552	−0.9466	0.033*
H7B	−0.3852	−0.3088	−0.9084	0.033*
N2	−0.25854 (12)	−0.2247 (3)	−0.9142 (4)	0.0536 (7)
H2A	−0.2222	−0.1780	−0.8788	0.064*
H2B	−0.2731	−0.2216	−1.0475	0.064*
O8	−0.5000	−0.5000	−0.1963 (4)	0.0299 (5)
H8	−0.4834 (19)	−0.557 (4)	−0.137 (6)	0.075 (13)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O4	0.0547 (10)	0.0333 (8)	0.0182 (7)	0.0123 (7)	−0.0039 (7)	0.0013 (7)
O2	0.0849 (14)	0.0347 (9)	0.0161 (8)	0.0254 (9)	−0.0033 (8)	−0.0006 (7)
O1	0.0497 (9)	0.0273 (8)	0.0244 (7)	0.0135 (7)	−0.0007 (7)	−0.0031 (7)
O3	0.0575 (11)	0.0317 (8)	0.0242 (8)	0.0175 (8)	−0.0039 (7)	−0.0066 (7)
C1	0.0322 (10)	0.0210 (9)	0.0172 (9)	0.0011 (8)	−0.0021 (7)	−0.0001 (8)
C4	0.0330 (10)	0.0210 (9)	0.0179 (9)	0.0015 (8)	−0.0005 (8)	−0.0019 (8)
C2	0.0403 (11)	0.0224 (10)	0.0182 (9)	0.0046 (8)	−0.0026 (9)	−0.0019 (8)
C3	0.0349 (11)	0.0240 (10)	0.0171 (9)	0.0016 (8)	−0.0027 (8)	−0.0010 (8)
O5	0.0385 (9)	0.0380 (9)	0.0219 (7)	0.0104 (7)	0.0002 (7)	−0.0003 (7)
N1	0.0278 (8)	0.0245 (9)	0.0309 (9)	0.0035 (6)	0.0020 (7)	−0.0019 (8)
C5	0.0232 (9)	0.0239 (10)	0.0258 (10)	0.0009 (7)	0.0005 (8)	−0.0026 (9)
O7	0.0420 (9)	0.0456 (10)	0.0287 (8)	−0.0204 (8)	−0.0074 (7)	0.0059 (8)
C6	0.0226 (9)	0.0213 (9)	0.0230 (10)	0.0003 (7)	−0.0022 (7)	−0.0044 (8)
O6	0.0446 (9)	0.0394 (10)	0.0245 (8)	0.0209 (7)	−0.0024 (6)	−0.0039 (7)
C8	0.0282 (10)	0.0319 (11)	0.0251 (10)	−0.0002 (9)	0.0016 (8)	0.0027 (9)
C7	0.0324 (11)	0.0304 (11)	0.0199 (9)	0.0005 (9)	−0.0029 (8)	−0.0002 (9)
N2	0.0452 (12)	0.0818 (19)	0.0338 (11)	−0.0240 (12)	−0.0022 (10)	0.0179 (13)
O8	0.0329 (12)	0.0291 (12)	0.0278 (12)	0.0085 (10)	0.000	0.000

Geometric parameters (Å, º)

O4—C4	1.234 (2)	O5—C5	1.204 (3)
O2—C2	1.304 (3)	N1—C6	1.481 (3)
O1—C1	1.249 (3)	C5—C6	1.523 (3)
O3—C3	1.236 (3)	C5—O6	1.308 (3)
C1—C4	1.493 (3)	O7—C8	1.238 (3)
C1—C2	1.429 (3)	C6—C7	1.520 (3)
C4—C3	1.489 (3)	C8—C7	1.510 (3)
C2—C3	1.448 (3)	C8—N2	1.311 (3)
O1—C1—C4	135.74 (19)	C2—C3—C4	87.99 (16)
O1—C1—C2	135.6 (2)	O5—C5—C6	122.5 (2)
C2—C1—C4	88.59 (16)	O5—C5—O6	126.1 (2)
O4—C4—C1	135.92 (18)	O6—C5—C6	111.34 (17)
O4—C4—C3	134.41 (19)	N1—C6—C5	109.14 (16)
C3—C4—C1	89.58 (15)	N1—C6—C7	111.23 (17)
O2—C2—C1	134.30 (19)	C7—C6—C5	114.20 (16)
O2—C2—C3	131.79 (18)	O7—C8—C7	119.72 (19)
C1—C2—C3	93.83 (17)	O7—C8—N2	123.1 (2)
O3—C3—C4	134.58 (19)	N2—C8—C7	117.2 (2)
O3—C3—C2	137.38 (19)	C8—C7—C6	112.48 (17)