Crystal structure and Hirshfeld surface analysis of poly[[di-μ3-glycine-lithium] perchlorate]

Revathi, P.; Mohan, J.S.; Balakrishnan, T.; Ramamurthi, K.; Thamotharan, S.

doi:10.1107/S2056989018018145

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 75| Part 2| February 2019| Pages 134-138

https://doi.org/10.1107/S2056989018018145

Open

access

Crystal structure and Hirshfeld surface analysis of poly[[di-μ₃-glycine-lithium] perchlorate]

Palanisamy Revathi,^a Janani S. Mohan,^b Thangavelu Balakrishnan,^a ‡ Kandasamy Ramamurthi ^c and Subbiah Thamotharan ^b ^*

^aCrystal Growth Laboratory, PG and Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli 620 023, India, ^bBiomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613 401, India, and ^cDepartment of Bio-Medical Engineering, Aarupadai Veedu Institute of Technology, Vinayaga Missions Research Foundation, Paiyanoor, Chennai 603 104, India
^*Correspondence e-mail: thamu@scbt.sastra.edu

Edited by J. Ellena, Universidade de Sâo Paulo, Brazil (Received 19 November 2018; accepted 20 December 2018; online 4 January 2019)

In the title salt, {[Li(C₂H₅NO₂)₂]ClO₄}_n, the Li⁺ cation is coordinated by four carboxylate oxygen atoms of the glycine molecules with a distorted tetrahedral geometry. The glycine exists in a zwitterionic form with protonated amino and deprotonated carboxylate groups. In the crystalline state, the title salt is primarily stabilized by intermolecular N—H⋯O and C^α—H⋯O interactions which interconnect various units. Hirshfeld surface analysis indicates that the intermolecular H⋯O/O⋯H interactions are the most important contributors to the crystal packing.

Keywords: crystal structure; zwitterionic glycine; C^α—H⋯O interactions; glycine⋯perchlorate interaction; distorted tetrahedral geometry.

CCDC reference: 1886641

1. Chemical context

As part of an ongoing effort aimed at the elucidation of the crystal and molecular structures of several metal complexes/co-crystals originating from simple amino acids (Balakrishnan et al., 2013a ,b ; Revathi et al., 2015 ; Sathiskumar et al., 2015a ,b ), we report herein the crystal structure of (I), a bis(glycinium)lithium perchlorate salt complex and discuss the hydrogen-bonding interactions it forms. The crystal packing and important molecular geometries of (I) are compared with a closely related structure bis(glycine)lithium nitrate salt complex (Baran et al., 2009 ).

2. Structural commentary

An ORTEP view of the title salt is shown in Fig. 1. The asymmetric unit contains two glycinium units, one Li cation and a perchlorate anion. Both glycine molecules exhibit a zwitterionic structure, as evident from the bond lengths involving the carboxylate atoms (Table 1) and the protonation of the N atoms of the glycine molecules. In (I), the torsion angle N1A—C2A—C1A—O1A in the one of the glycinium is −0.18 (19)°, while the corresponding angle is 20.75 (18)° in the other glycinium. The superposition of these two glycine molecules involving non-hydrogen atoms reveals high degree of similarity with an r.m.s.d. value of 0.13 Å, the maximum deviation (0.19 Å) being observed at the C^α (C2A and C2B) atom.

Table 1
Selected geometric parameters (Å, °)

O1A—Li1ⁱ	1.991 (3)	O2A—Li1	2.015 (3)
O2A—Li1ⁱⁱ	1.966 (3)	O1B—Li1	1.906 (3)

O1B—Li1—O1Aⁱⁱⁱ	108.95 (12)	O1B—Li1—O2A	102.15 (11)
O2A^iv—Li1—O1Aⁱⁱⁱ	102.03 (11)	O2A^iv—Li1—O2A	109.18 (12)
Symmetry codes: (i) x, y-1, z; (ii) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) x, y+1, z; (iv) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Figure 1
Part of the crystal structure of (I)

showing the atomic labelling. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (a) x, y − 1, z; (b) x, y + 1, z; (c) −x + 1, y − $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (d) −x + 1, y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ].

In the crystal, the Li cation is coordinated by four carboxylate oxygen atoms of the glycine molecules. One oxygen atom from each glycine molecule is incorporated in the Li coordination sphere with Li—O distances ranging from 1.906 (3) to 2.015 (3) Å. The geometry around the Li cation is distorted tetrahedral, as discernible from the angles around the Li cation (Table 1). The lithium coordination is extended as a layer that runs parallel to the b axis. The distance between two adjacent Li ions is 3.270 (13) Å.

In a closely related structure of the complex bis(glycine) lithium nitrate (Baran et al., 2009), the Li cation is surrounded by four carboxylate oxygen atoms in a distorted tetrahedral geometry as in (I). The distance between two adjacent Li ions is 5.034 Å.

3. Supramolecular features

As shown in Table 2, the title salt is stabilized by a network of intermolecular N—H⋯O, N—H⋯Cl and C^α—H⋯O interactions. Overall, the crystal structure of the title salt can be described as alternate layers of perchlorate anions and Li-glycine cations (Fig. 2); these layers extend along the c-axis direction. In the crystalline state, each of the zwitterionic glycine molecule is arranged in a different way. The first glycine, molecule A (shown in grey), forms double arrays that run parallel to the b- and c-axis directions. In the array parallel to the b axis, the molecules are oriented in opposite directions, as shown in Fig. 3. The first glycine molecule also forms arrays running parallel to the b axis. The second glycine molecules (shown in orange) and the perchlorate anions are sandwiched between adjacent arrays formed by the first glycinium molecules (Fig. 3). Similar packing features are observed for bis(glycine)lithium nitrate (Baran et al., 2009).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1A—H11⋯Cl1^v	0.88 (3)	2.97 (3)	3.7635 (17)	151 (2)
N1A—H11⋯O4^v	0.88 (3)	2.16 (3)	3.037 (2)	178 (2)
N1A—H12⋯O5^vi	0.90 (3)	2.23 (3)	2.965 (2)	139 (2)
N1A—H12⋯O6^vii	0.90 (3)	2.51 (3)	3.125 (2)	126 (2)
N1A—H13⋯O4	0.85 (3)	2.29 (3)	3.091 (2)	156 (2)
N1B—H14⋯O2Bⁱ	0.90 (2)	2.00 (2)	2.8653 (19)	160.5 (18)
N1B—H15⋯O1A^viii	0.89 (2)	2.05 (2)	2.9308 (16)	169.8 (19)
N1B—H16⋯O1B^ix	0.93 (2)	2.35 (3)	2.9249 (17)	119 (2)
N1B—H16⋯O2B^x	0.93 (2)	2.28 (2)	3.119 (2)	150 (2)
C2A—H21⋯O1B	0.97	2.63	3.3747 (18)	134
C2A—H22⋯O5^v	0.97	2.44	3.185 (2)	133
C2B—H23⋯O2A^xi	0.97	2.60	3.4867 (18)	152
C2B—H24⋯O4ⁱⁱⁱ	0.97	2.55	3.360 (2)	141
Symmetry codes: (i) x, y-1, z; (iii) x, y+1, z; (v) $[-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vi) $[-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vii) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (viii) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (ix) -x+1, -y+1, -z+1; (x) -x+1, -y+2, -z+1; (xi) $[x, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ .

Figure 2
The crystal structure of (I)

, comprising alternate layers of Li–glycinium units and perchlorate anions, viewed down the b axis. Hydrogen bonds are indicated by dashed lines.

Figure 3
Second glycinium molecules (orange) and perchlorate anions are sandwiched between arrays of the first glycinium molecules (grey).

Furthermore, a careful examination of the crystal structure reveals that the first glycinium molecule does not self-assemble in the solid state. It interacts with the perchlorate anion through intermolecular N—H⋯O and N—H⋯Cl interactions and with the second glycinium via intermolecular C^α—H⋯O interactions. In contrast, the second glycinium molecule is able to self-associate in the crystal through N—H⋯O interactions (involving H14⋯O2B and H16⋯O2B). The former linear hydrogen bond links the glycinium molecules in a head-to-tail fashion in which amino acids are self-associated via their amino and carboxylate groups. This is one of the characteristic features observed in many amino acids and amino acid complexes (Sharma et al., 2006 ; Selvaraj et al., 2007 ; Balakrishnan et al., 2013a,b; Revathi et al., 2015). Moreover, this head-to-tail chain sequence extends along the b-axis direction and adjacent chains are oriented in an anti-parallel fashion. Centrosymmetrically related dimers [R₂²(10) motif] of the second glycinium molecules are generated through H16⋯O2B interactions. Together, the H14⋯O2B and H16⋯O2B interactions lead to alternating R₂²(10) and R₄²(8) motifs (Fig. 4).

Figure 4
Anti-parallel glycinium arrays showing the formation of alternate R₂²(10) and R₄²(8) motifs.

The protonated amino group of the first glycinium (mol A) is involved in five hydrogen-bonding (N—H⋯O and N—H⋯Cl) interactions (see Table 2). One of the bifurcated hydrogen-bonding interactions is formed between H12 and atoms O5 and O6 of the perchlorate anions. This interactions generate an R₂⁴(8) loop motif in which two glycinium and two perchlorate ions are involved [Fig. 5(a)]. Intermolecular N1A—H13⋯O4 and C2A—H21⋯O3 interactions connect the glycinium molecules and perchlorate anions into a loop with adjacent loops being interconnected by C2A—H22⋯O5 interactions [Fig. 5(b)]. As mentioned earlier, the second glycinium interacts with carboxylate groups through its protonated amino group (N1B) (Fig. 4). It also interacts with the perchlorate anion through C2B—H24⋯O4 interaction.

Figure 5
(a) The glycinium molecules and perchlorate anions form a closed R₂⁴(8) loop through intermolecular N—H⋯O hydrogen bonds. (b) The glycinium molecules and perchlorate anions are interconnected by N—H⋯O and C^α—H⋯O interactions, forming a ring motif, with adjacent rings connected by C^α—H⋯O interactions.

4. Hirshfeld surface analysis and 2D fingerprint plots

The Hirshfeld surface (HS) analysis was carried out in order to understand the nature of the intermolecular interactions present in the crystal structure. The shorter and longer contacts are indicated as red and blue spots on the HS and contacts with distances equal to the sum of the van der Waals radii are represented as white. The Hirshfeld surfaces for the cation (consisting of two glycinium molecules and a lithium ion) and anion of the title salt complex were generated and analysed separately using the program CrystalExplorer (Wolff et al., 2012 ). The HS of the cation mapped over the normalized distance, d_norm, and the 2D fingerprint plots (Spackman & McKinnon, 2002 ) are illustrated in Fig. 6. In the cation, intermolecular O⋯H/H⋯O interactions are predominant making a 66.9% contribution to the total HS. In the two-dimensional fingerprint plots, these contacts are depicted as a pair of sharp spikes with d_e + d_i ∼1.9 Å. There is a remarkable difference observed in the relative contribution of the H⋯O (donor region where d_e > d_i) and O⋯H (acceptor region where d_e < d_i) contacts. The former contact contributes 47.3%, while the contribution of the latter reciprocal contact is 19.6%. Similarly, the relative contribution of the Li⋯O/O⋯Li contacts is calculated to be 12.7% and these contacts appear as sharp spikes at a distance of around 1.9 Å. The proportions of Li⋯O and O⋯Li contacts are comparable (5.9 and 6.8%, respectively). The H⋯H contacts contribute 11.3% to the total HS of the cation part. The H⋯Li/Li⋯H (2.5%), O⋯C/C⋯O (2.4%) and O⋯O (2.0%) contacts play a minor role in the stabilization of the crystal structure.

Figure 6
(a) Hirshfeld surface of the bis(glycinium)lithium unit and (b) two-dimensional fingerprint plots for the intermolecular O⋯H/H⋯O and Li⋯O/O⋯Li contacts.

In the perchlorate anion, the relative contributions of the O⋯H/H⋯O and O⋯O contacts are 81.4 and 18.2%, respectively (Fig. 7). The O⋯H/H⋯O contacts visible on the HS are due to the N—H⋯O and C—H⋯O hydrogen bonds. The O⋯O contacts are also visible on the HS and this contact of around 2.8 Å has the shortest distances of d_e and d_i of around 1.4 Å (Fig. 8). This O⋯O short contact [2.879 (2) Å] links the anionic molecules into a chain running parallel to the b-axis direction.

Figure 7
(a) Hirshfeld surface of the perchlorate unit and (b) two-dimensional fingerprint plots for the intermolecular O⋯H/H⋯O and O⋯O contacts.

Figure 8
An intermolecular O⋯O contact interconnects adjacent percholorate anions.

5. Database survey

A search of the Cambridge Structural Database (CSD, version 5.39, last update August 2018; Groom et al., 2016 ) using the keywords `lithium (name)' and `amino-acids, peptides and complexes (class)' yielded 50 hits of which 18 are glycine amino acids. In most of the complexes, carboxylate oxygen atoms are involved in the Li coordination as described in the following examples. In the catena-[μ³-glycinato-O,O′)-(nitrato-O)lithium] complex, one of oxygen atoms of the nitro group is involved in the Li coordination along with the glycine carboxylate O atoms (ALUNEA, Baran et al., 2003 ). In three complexes (HEFWUK, Müller et al., 1994 ; NEPWUC, Balakrishnan et al., 2013b; UCIYOV, Fleck et al., 2006 ), the water O atom and three glycine carboxylate O atoms participate in the Li coordination. In the catena-[[μ⁴-glycyl-N,O,O,O′]lithium] complex (HEFXAR, Müller et al., 1994), the deprotonated amino group N atom is involved in the Li coordination sphere and in cyclo[tris(glycyl-prolyl-O)]isothiocyanatolithium trihydrate (YUWXUJ, Thomas et al., 1994 ), the N atom of the isothiocynate, which acts as a fourth ligand, participates in the Li coordination sphere.

A detailed survey was also been conducted in the protein data bank (www.rcsb.org) to understand the Li⁺ coordination with protein molecules. The keyword `lithium' was used in the search, which resulted in 74 hits (up to 3.0 Å resolution). There are 30 structures found with better than 1.5 Å resolution and these structures were examined further. In this dataset, we found that Li is three- to six-coordinate with a water molecule belonging to the Li complex cation. Moreover, the residues aspartate and glutamate are included in the Li coordination in several structures.

6. Synthesis and crystallization

The title salt was synthesized by dissolving AR-grade glycine and lithium perchlorate in a 2:1 stoichiometric ratio in double distilled water and stirred continuously for 2 h. Slow evaporation of this aqueous solution at room temperature yielded transparent colourless single crystals of the title salt.

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. The positions of N-bound H atoms were located from a difference-Fourier map and refined freely along with their isotropic displacement parameters. The remaining H atoms were placed in calculated positions (C—H = 0.97 Å) and refined as riding with U_iso(H) = 1.2U_eq(C). Reflections 1 0 0 and 0 0 2 were obscured by the beam stop and were omitted during final refinement cycle.

Table 3
Experimental details

Crystal data
Chemical formula	[Li(C₂H₅NO₂)₂]ClO₄
M_r	256.53
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	12.7792 (14), 5.2144 (4), 15.6368 (18)
β (°)	111.808 (4)
V (Å³)	967.40 (17)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.43
Crystal size (mm)	0.35 × 0.30 × 0.30

Data collection
Diffractometer	Bruker Kappa APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2004 )
T_min, T_max	0.865, 0.883
No. of measured, independent and observed [I > 2σ(I)] reflections	7318, 2304, 2047
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.662

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.092, 1.07
No. of reflections	2304
No. of parameters	170
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.42
Computer programs: APEX2, SAINT and XPREP (Bruker, 2004), SIR92 (Altomare et al., 1994 ), SHELXL2014/7 (Sheldrick, 2015 ), PLATON (Spek, 2009 ), Mercury (Macrae et al., 2008 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1886641

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989018018145/ex2017sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018018145/ex2017Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Poly[[di-µ₃-glycine-lithium] perchlorate] top

Crystal data top

[Li(C₂H₅NO₂)₂]ClO₄	F(000) = 528
M_r = 256.53	D_x = 1.761 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 12.7792 (14) Å	Cell parameters from 4824 reflections
b = 5.2144 (4) Å	θ = 5.4–56.2°
c = 15.6368 (18) Å	µ = 0.43 mm⁻¹
β = 111.808 (4)°	T = 296 K
V = 967.40 (17) Å³	Block, colourless
Z = 4	0.35 × 0.30 × 0.30 mm

Data collection top

Bruker Kappa APEXII CCD diffractometer	2047 reflections with I > 2σ(I)
ω and φ scan	R_int = 0.023
Absorption correction: multi-scan (SADABS; Bruker, 2004)	θ_max = 28.1°, θ_min = 3.4°
T_min = 0.865, T_max = 0.883	h = −16→16
7318 measured reflections	k = −6→4
2304 independent reflections	l = −20→20

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.033	w = 1/[σ²(F_o²) + (0.0468P)² + 0.4555P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.092	(Δ/σ)_max < 0.001
S = 1.07	Δρ_max = 0.52 e Å⁻³
2304 reflections	Δρ_min = −0.42 e Å⁻³
170 parameters	Extinction correction: SHELXL2014/7 (Sheldrick 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.051 (3)

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

	x	y	z	U_iso*/U_eq
O1A	0.32780 (8)	0.05574 (18)	0.19473 (6)	0.0197 (2)
O2A	0.41860 (8)	0.43353 (19)	0.22629 (7)	0.0215 (2)
O1B	0.41750 (10)	0.7653 (2)	0.38667 (7)	0.0268 (3)
O2B	0.37499 (12)	1.1669 (2)	0.41178 (8)	0.0356 (3)
N1A	0.13201 (12)	0.2513 (3)	0.19284 (12)	0.0312 (3)
H11	0.068 (2)	0.335 (5)	0.1779 (16)	0.049 (6)*
H12	0.128 (2)	0.138 (6)	0.1487 (19)	0.062 (7)*
H13	0.135 (2)	0.163 (5)	0.2393 (19)	0.056 (7)*
N1B	0.38884 (12)	0.5778 (3)	0.53719 (9)	0.0255 (3)
H14	0.3687 (17)	0.465 (4)	0.4903 (16)	0.037 (5)*
H15	0.3625 (17)	0.529 (4)	0.5801 (15)	0.037 (5)*
H16	0.466 (2)	0.599 (5)	0.5661 (16)	0.051 (7)*
C1A	0.33341 (11)	0.2912 (3)	0.21201 (8)	0.0157 (3)
C1B	0.38168 (11)	0.9307 (3)	0.42732 (9)	0.0198 (3)
C2A	0.22888 (11)	0.4280 (3)	0.21347 (10)	0.0224 (3)
H21	0.2455	0.5039	0.2737	0.027*
H22	0.2090	0.5653	0.1684	0.027*
C2B	0.34142 (13)	0.8330 (3)	0.50229 (10)	0.0229 (3)
H23	0.3636	0.9542	0.5530	0.027*
H24	0.2598	0.8225	0.4775	0.027*
Li1	0.4371 (2)	0.7982 (5)	0.27213 (16)	0.0196 (5)
Cl1	0.07919 (3)	0.27547 (7)	0.41247 (3)	0.02800 (14)
O3	0.09668 (13)	0.4960 (3)	0.36429 (11)	0.0504 (4)
O4	0.08777 (12)	0.0478 (2)	0.36201 (10)	0.0453 (4)
O5	−0.03202 (11)	0.2865 (3)	0.41610 (11)	0.0483 (4)
O6	0.16270 (12)	0.2672 (3)	0.50378 (9)	0.0506 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1A	0.0213 (5)	0.0155 (5)	0.0206 (5)	0.0022 (4)	0.0060 (4)	−0.0015 (4)
O2A	0.0183 (5)	0.0196 (5)	0.0296 (5)	−0.0016 (4)	0.0123 (4)	−0.0026 (4)
O1B	0.0422 (7)	0.0217 (5)	0.0228 (5)	0.0042 (4)	0.0192 (5)	0.0016 (4)
O2B	0.0639 (8)	0.0171 (5)	0.0338 (6)	0.0026 (5)	0.0275 (6)	0.0039 (4)
N1A	0.0194 (6)	0.0278 (7)	0.0493 (9)	−0.0026 (5)	0.0160 (6)	−0.0073 (7)
N1B	0.0357 (7)	0.0230 (7)	0.0248 (6)	0.0074 (5)	0.0192 (6)	0.0075 (5)
C1A	0.0161 (6)	0.0176 (6)	0.0129 (5)	0.0019 (5)	0.0050 (4)	0.0005 (4)
C1B	0.0256 (7)	0.0175 (7)	0.0167 (6)	−0.0007 (5)	0.0081 (5)	0.0006 (5)
C2A	0.0169 (6)	0.0182 (7)	0.0324 (7)	0.0002 (5)	0.0096 (5)	−0.0038 (5)
C2B	0.0312 (7)	0.0180 (7)	0.0246 (7)	0.0043 (5)	0.0163 (6)	0.0029 (5)
Li1	0.0217 (11)	0.0180 (11)	0.0206 (10)	0.0008 (9)	0.0096 (9)	0.0017 (9)
Cl1	0.0232 (2)	0.0203 (2)	0.0330 (2)	0.00037 (12)	0.00177 (15)	−0.00111 (13)
O3	0.0580 (9)	0.0278 (7)	0.0699 (10)	0.0008 (6)	0.0290 (8)	0.0097 (6)
O4	0.0509 (8)	0.0263 (7)	0.0500 (8)	0.0016 (5)	0.0085 (6)	−0.0107 (6)
O5	0.0259 (7)	0.0473 (8)	0.0679 (10)	−0.0025 (5)	0.0131 (6)	−0.0002 (7)
O6	0.0341 (7)	0.0704 (11)	0.0346 (7)	0.0116 (6)	−0.0019 (6)	−0.0082 (6)

Geometric parameters (Å, º) top

O1A—C1A	1.2535 (16)	N1B—H16	0.93 (2)
O1A—Li1ⁱ	1.991 (3)	C1A—C2A	1.5219 (18)
O2A—C1A	1.2670 (16)	C1B—C2B	1.5318 (19)
O2A—Li1ⁱⁱ	1.966 (3)	C2A—H21	0.9700
O2A—Li1	2.015 (3)	C2A—H22	0.9700
O1B—C1B	1.2543 (17)	C2B—H23	0.9700
O1B—Li1	1.906 (3)	C2B—H24	0.9700
O2B—C1B	1.2525 (18)	Li1—O2Aⁱⁱⁱ	1.966 (3)
N1A—C2A	1.4793 (19)	Li1—O1A^iv	1.991 (3)
N1A—H11	0.88 (3)	Li1—Li1ⁱⁱⁱ	3.270 (3)
N1A—H12	0.90 (3)	Li1—Li1ⁱⁱ	3.270 (3)
N1A—H13	0.85 (3)	Cl1—O6	1.4308 (13)
N1B—C2B	1.4796 (19)	Cl1—O3	1.4371 (14)
N1B—H14	0.90 (2)	Cl1—O5	1.4443 (14)
N1B—H15	0.89 (2)	Cl1—O4	1.4521 (13)

C1A—O1A—Li1ⁱ	123.96 (11)	H21—C2A—H22	107.9
C1A—O2A—Li1ⁱⁱ	122.18 (11)	N1B—C2B—C1B	111.92 (12)
C1A—O2A—Li1	126.51 (11)	N1B—C2B—H23	109.2
Li1ⁱⁱ—O2A—Li1	110.42 (9)	C1B—C2B—H23	109.2
C1B—O1B—Li1	127.90 (12)	N1B—C2B—H24	109.2
C2A—N1A—H11	111.7 (17)	C1B—C2B—H24	109.2
C2A—N1A—H12	112.5 (17)	H23—C2B—H24	107.9
H11—N1A—H12	110 (2)	O1B—Li1—O2Aⁱⁱⁱ	118.06 (13)
C2A—N1A—H13	112.8 (17)	O1B—Li1—O1A^iv	108.95 (12)
H11—N1A—H13	104 (2)	O2Aⁱⁱⁱ—Li1—O1A^iv	102.03 (11)
H12—N1A—H13	106 (2)	O1B—Li1—O2A	102.15 (11)
C2B—N1B—H14	109.4 (13)	O2Aⁱⁱⁱ—Li1—O2A	109.18 (12)
C2B—N1B—H15	108.6 (13)	O1A^iv—Li1—O2A	117.22 (12)
H14—N1B—H15	110.6 (19)	O1B—Li1—Li1ⁱⁱⁱ	121.15 (12)
C2B—N1B—H16	106.7 (16)	O2Aⁱⁱⁱ—Li1—Li1ⁱⁱⁱ	35.28 (8)
H14—N1B—H16	114 (2)	O1A^iv—Li1—Li1ⁱⁱⁱ	67.82 (6)
H15—N1B—H16	107.5 (19)	O2A—Li1—Li1ⁱⁱⁱ	132.77 (14)
O1A—C1A—O2A	126.04 (12)	O1B—Li1—Li1ⁱⁱ	111.95 (11)
O1A—C1A—C2A	118.81 (12)	O2Aⁱⁱⁱ—Li1—Li1ⁱⁱ	75.88 (12)
O2A—C1A—C2A	115.11 (12)	O1A^iv—Li1—Li1ⁱⁱ	134.29 (14)
O2B—C1B—O1B	126.11 (13)	O2A—Li1—Li1ⁱⁱ	34.30 (3)
O2B—C1B—C2B	117.23 (13)	Li1ⁱⁱⁱ—Li1—Li1ⁱⁱ	105.77 (13)
O1B—C1B—C2B	116.66 (12)	O6—Cl1—O3	110.10 (10)
N1A—C2A—C1A	111.90 (12)	O6—Cl1—O5	110.00 (9)
N1A—C2A—H21	109.2	O3—Cl1—O5	109.62 (9)
C1A—C2A—H21	109.2	O6—Cl1—O4	109.79 (8)
N1A—C2A—H22	109.2	O3—Cl1—O4	108.16 (9)
C1A—C2A—H22	109.2	O5—Cl1—O4	109.15 (8)

Li1ⁱ—O1A—C1A—O2A	53.01 (19)	Li1—O1B—C1B—O2B	−17.0 (2)
Li1ⁱ—O1A—C1A—C2A	−129.18 (14)	Li1—O1B—C1B—C2B	162.37 (14)
Li1ⁱⁱ—O2A—C1A—O1A	−2.3 (2)	O1A—C1A—C2A—N1A	−0.18 (19)
Li1—O2A—C1A—O1A	−170.40 (12)	O2A—C1A—C2A—N1A	177.86 (13)
Li1ⁱⁱ—O2A—C1A—C2A	179.83 (12)	O2B—C1B—C2B—N1B	−159.82 (14)
Li1—O2A—C1A—C2A	11.73 (18)	O1B—C1B—C2B—N1B	20.75 (18)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1A—H11···Cl1^v	0.88 (3)	2.97 (3)	3.7635 (17)	151 (2)
N1A—H11···O4^v	0.88 (3)	2.16 (3)	3.037 (2)	178 (2)
N1A—H12···O5^vi	0.90 (3)	2.23 (3)	2.965 (2)	139 (2)
N1A—H12···O6^vii	0.90 (3)	2.51 (3)	3.125 (2)	126 (2)
N1A—H13···O4	0.85 (3)	2.29 (3)	3.091 (2)	156 (2)
N1B—H14···O2Bⁱ	0.90 (2)	2.00 (2)	2.8653 (19)	160.5 (18)
N1B—H15···O1A^viii	0.89 (2)	2.05 (2)	2.9308 (16)	169.8 (19)
N1B—H16···O1B^ix	0.93 (2)	2.35 (3)	2.9249 (17)	119 (2)
N1B—H16···O2B^x	0.93 (2)	2.28 (2)	3.119 (2)	150 (2)
C2A—H21···O1B	0.97	2.63	3.3747 (18)	134
C2A—H22···O5^v	0.97	2.44	3.185 (2)	133
C2B—H23···O2A^xi	0.97	2.60	3.4867 (18)	152
C2B—H24···O4^iv	0.97	2.55	3.360 (2)	141

Symmetry codes: (i) x, y−1, z; (iv) x, y+1, z; (v) −x, y+1/2, −z+1/2; (vi) −x, y−1/2, −z+1/2; (vii) x, −y+1/2, z−1/2; (viii) x, −y+1/2, z+1/2; (ix) −x+1, −y+1, −z+1; (x) −x+1, −y+2, −z+1; (xi) x, −y+3/2, z+1/2.

Footnotes

‡Additional correspondence author, email: balacrystalgrowth@gmail.com.

Funding information

TB and PR acknowledge the Tamil Nadu State Council for Science and Technology, Tamil Nadu, for providing funding under a Major Research Project Scheme (TNSCST/S&T project/PS/ RJ/2013–2014). ST is very grateful to the management of SASTRA Deemed University for infrastructure and financial support (Professor TRR grant).

References

Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435. CrossRef Web of Science IUCr Journals Google Scholar
Balakrishnan, T., Ramamurthi, K., Jeyakanthan, J. & Thamotharan, S. (2013b). Acta Cryst. E69, m60–m61. CrossRef IUCr Journals Google Scholar
Balakrishnan, T., Ramamurthi, K. & Thamotharan, S. (2013a). Acta Cryst. E69, o57. CrossRef IUCr Journals Google Scholar
Baran, J., Drozd, M., Pietraszko, A., Trzebiatowska, M. & Ratajczak, H. (2003). Pol. J. Chem. 77, 1561–1577. CAS Google Scholar
Baran, J., Drozd, M., Ratajczak, H. & Pierraszko, A. (2009). J. Mol. Struct. 927, 42–49. CrossRef Google Scholar
Bruker (2004). APEX2, SAINT, XPREP and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Fleck, M., Schwendtner, K. & Hensler, A. (2006). Acta Cryst. C62, m122–m125. Web of Science CrossRef CAS IUCr Journals Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Müller, G., Maier, G.-M. & Lutz, M. (1994). Inorg. Chim. Acta, 218, 121–131. CrossRef Web of Science Google Scholar
Revathi, P., Balakrishnan, T., Ramamurthi, K. & Thamotharan, S. (2015). Acta Cryst. E71, 875–878. Web of Science CrossRef IUCr Journals Google Scholar
Sathiskumar, S., Balakrishnan, T., Ramamurthi, K. & Thamotharan, S. (2015a). Spectrochim. Acta A Mol. Biomol. Spectrosc. 138, 187–194. CrossRef CAS Google Scholar
Sathiskumar, S., Balakrishnan, T., Ramamurthi, K. & Thamotharan, S. (2015b). Acta Cryst. E71, 217–219. CrossRef IUCr Journals Google Scholar
Selvaraj, M., Thamotharan, S., Roy, S. & Vijayan, M. (2007). Acta Cryst. B63, 459–468. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sharma, A., Thamotharan, S., Roy, S. & Vijayan, M. (2006). Acta Cryst. C62, o148–o152. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spackman, M. A. & McKinnon, J. J. (2002). CrystEngComm, 4, 378–392. Web of Science CrossRef CAS Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Thomas, L. M., Ramasubbu, N. & Bhandary, K. K. (1994). Biopolymers, 34, 1007–1013. CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wolff, S. K., Grimwood, D. J., McKinnon, J. J., Turner, M. J., Jayatilaka, D. & Spackman, M. A. (2012). CrystalExplorer. The University of Western Australia. Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.