Crystal structure and photoluminescent properties of bis­(4′-chloro-2,2′:6′,2′′-terpyrid­yl)cobalt(II) dichloride tetra­hydrate

Thippeswamy, B.; Suchetan, P.A.; Mahadevan, K.M.; Nagabhushana, H.; Vijayakumar, G.R.

doi:10.1107/S205698902000287X

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Volume 76| Part 4| April 2020| Pages 496-499

https://doi.org/10.1107/S205698902000287X

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Crystal structure and photoluminescent properties of bis(4′-chloro-2,2′:6′,2′′-terpyridyl)cobalt(II) dichloride tetrahydrate

B. Thippeswamy,^a,^b P. A. Suchetan,^a K. M. Mahadevan,^c H. Nagabhushana ^d and G. R. Vijayakumar ^a ^*

^aDepartment of Chemistry, University College of Science, Tumkur University, Tumkur, Karnataka 572 103, India, ^bDepartment of Chemistry, Government Science College, Chitradurga, 577501, India, ^cDepartment of Chemistry, Kuvempu University, P. G. Centre, Kadur-577548, India, and ^dProf. C. N. R Rao Centre for Advanced Materials Research, Tumkur University, Tumkur-572 103, India
^*Correspondence e-mail: vijaykumargr18@gmail.com

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 23 December 2019; accepted 1 March 2020; online 5 March 2020)

In the title hydrated complex, [Co(C₁₅H₁₀ClN₃)₂]Cl₂·4H₂O, the complete dication is generated by $[\overline{4}]$ symmetry. The CoN₆ moiety shows distortion from regular octahedral geometry with the trans bond angles of two N—Co—N units being 160.62 (9)°. In the crystal, O—H⋯Cl and C—H⋯O interactions link the components into (001) sheets. The title compound exhibits blue-light emission, as indicated by photoluminescence data, and a HOMO–LUMO energy separation of 2.23 eV was obtained from its diffuse reflectance spectrum.

Keywords: crystal structure; 2,2′,6′,2′′-terpyridine; photoluminescence; SEM; TG–DTA.

CCDC reference: 1914486

1. Chemical context

Since the pioneering work of Tang et al. (1987 ), there has been increasing interest in chelating organic compounds being employed as charge-transporting materials in electronic devices such as OLEDs. Transition-metal complexes are promising candidates for use as hole-transporting materials as the metal ions can assume variable oxidation states and are found to exhibit low kinetic barriers for self-exchange reactions (Marcus, 1965 ).

As 2,2′-bipyridine (bpy) is reported to show both σ-donor and π-acceptor capabilities, disubstituted 4,4′-, 5,5′- and 6,6′-derivatives of bpy have been widely employed in supramolecular and coordination chemistry (Kaes et al., 2000 ; Williams et al., 2002 ). Materials incorporating pyridine have also been shown to perform well in electron-transporting layers in OLEDs because of their high electron mobility (Ichikawa et al., 2010 ).

Single-layer device structures that make use of Ru^II complexes involving bipyridine and its derivatives not only show the potential to transport both holes and electrons but also exhibit luminescent properties (Rudmann & Rubner, 2001 ; Gao & Bard, 2000 ). Reports of the application of cyclometalated Ir^III complexes in vapour-deposited OLEDs both as efficient emissive and charge-transporting materials (Adamovich et al., 2003 ; Grushin et al., 2001 ) and the luminescent properties of a distorted octahedral Ni^II complex with 5,5′-dimethyl-2,2′-bipyridine have been published (Abedi et al., 2015 ). The synthesis and a study of the thermal and luminescent properties of d⁸ transition-metal complexes with the incorporation of substituted 2,2′;6′,2′′-terpyridine ligands were described by Momeni et al. (2017 ).

As an extension of such studies, we now report the synthesis, structure, spectroscopic characterization and thermal behaviour of the title complex, (I).

2. Structural commentary

The [Co(C₁₅H₁₀N₃)₂Cl₂]²⁺ cation in (I) is symmetric (the metal atom lies on a special position with $[\overline{4}]$ site symmetry; atoms N2, C8 and Cl1 lie on a crystallographic twofold axis), thus the asymmetric unit contains half of the ligand coordinated to the cobalt ion, one water molecule of crystallization (O atom site symmetry 1) and half of a chloride counter-ion (site symmetry 2) (Fig. 1). The complex shows distortion from an ideal octahedral geometry for the metal ion with two N1—Co1—N1 bond angles being 160.62 (9)°. However, the N2—Co1—N2 bond angle is 180°, as it lies on the rotoinversion axis. The coordinated ligand is almost planar with the r.m.s. deviation of all the non-hydrogen atoms being 0.025 Å. Moreover, the dihedral angle between the ligands is 90.0°, as constrained by the presence of the rotoinversion axis.

Figure 1
The molecular structure of (I)

with displacement ellipsoids drawn at the 50% probability level. The complete cation of the complex is generated by applying the symmetry operations (a) −y + $[{5\over 4}]$ , x + $[{1\over 4}]$ , −z + $[{5\over 4}]$ , (b) −x + 1, −y + $[{3\over 2}]$ , z and (c) y − $[{1\over 4}]$ , −x + $[{5\over 4}]$ , −z + $[{5\over 4}]$ .

3. Supramolecular features

The unit cell of (I) contains four cations, which are electrically balanced by eight chloride ions along with sixteen water molecules of crystallization (Fig. 2). In the crystal structure, two pairs of O—H⋯Cl hydrogen bonds between water molecules and chloride ions [O2—H2O1⋯Cl2 and O2—H1O1⋯Cl2] link the components into infinite (001) sheets (Table 1).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H2O1⋯Cl2	0.82	2.35	3.1735	177
O1—H1O1⋯Cl2ⁱ	0.84	2.43	3.2607	170
C7—H7⋯O1ⁱⁱ	0.93	2.44	3.334 (4)	161
Symmetry codes: (i) -x, -y+1, -z+1; (ii) $[x, y+{\script{1\over 2}}, -z+1]$ .

Figure 2
A partial view of the crystal packing of (I)

viewed down [100]. Hydrogen bonds are shown as thin blue lines.

4. Thermal and photoluminescence studies

Thermogravimetry (TG) and differential thermal analysis (DTA) on (I) show progressive decomposition in several steps. The first mass loss (obs. 10.0%, calc. 9.8% over the temperature range 60–140°C) is attributed to the loss of the water molecules of crystallization, accompanied by endotherms at 78 and 134°C. The second mass loss over the temperature range 200–310°C accompanied by a DTA peak at 306°C is probably due to the decomposition of one ligand with an estimated mass loss of 36.1% (calcd. mass loss 36.2%). Powder XRD of the final residue after heating to 800°C indicated the presence of cobalt oxy hydroxide, CoO(OH) and Co₃O₄ (Sulikowska et al., 2000 ).

The diffuse reflectance (DR) spectrum of (I) was scanned in the wavelength range 200–1100 nm and an absorption band appeared in the visible region as shown in Fig. 3a. A prominent peak with a diffuse reflectance percentage of 5.4 is observed at 640 nm. The Kubelka–Munk function (Harry, 1976 ) (Fig. 3b) was used in order to determine the HOMO–LUMO gap for (I): the band gap energy obtained from the plot was found to be 2.23 eV (Morales et al., 2007 ).

Figure 3
(a) Diffuse reflectance spectrum of (I)

(b) Plot of [F(R_∞)hν]^1/2 versus energy for (I)

The excitation and emission spectra of (I) recorded at room temperature are shown in Fig. 4a and b. The excitation spectrum shows features at 318, 339, 382 and 395 nm. From the emission spectrum, three well-defined peaks at 436, 541 and 653 nm are apparent for (I). The determination of chromaticity co-ordinates [Publication CIE No 15.2 (1986 ) and 17.4 (1987 )] was carried out at an excitation wavelength of 395 nm. The estimated CIE values for the probable excitation are incorporated in the left corner of Fig. 4c. The colour of emission for the highlighted phosphor is indicated in the chromaticity diagram by the solid circle sign (star), which indicates that the emission colour is blue.

Figure 4
Photoluminescence spectra of (I)

; (a) excitation spectrum (b) emission spectrum (c) CIE graph

5. Database survey

A search of the Cambridge Structural Database gave 90 matches for crystal structures containing the 4′-chloro-2,2′;6′,2′′-terpyridine (L) ligand. Closely related complexes to (I) with a pair of chelating L ligands generating an MN₆ coordination sphere include the nickel and iron complexes [Ni(L-κ³N,N′,N′′)₂]Cl₂·3H₂O (CCDC refcode HIVPUY; Huang et al., 2008 ) and [Fe(L-κ³N,N′,N′′)₂]Cl₂·4H₂O (HIVQEJ; Huang et al., 2008); the latter complex is isostructural with (I). The structure of [Ru(L-κ³N,N′,N′′)₂]Cl₂·2H₂O (PAYMOT; Wang et al., 2012 ) has also been described. The dihedral angles between the L ligands in HIVPUY, HIVQEJ and PAYMOT are 94.9 (3), 86.1 (3) and 87.0 (3)°, respectively. The crystals of both HIVPUY and HIVQEJ display three-dimensional networks arising from O—H⋯Cl and C—H⋯O interactions. In PAYMOT, the cations, anions and water molecules are linked into a three-dimensional network by C—H⋯Cl, C—H⋯O and O—H⋯Cl hydrogen bonds.

6. Synthesis and crystallization

A solution of 4′-chloro-2,2′;6′,2′′-terpyridine (2) (0.535 g, 2.00 mmol) in 3 ml of ethanol was stirred at 333 K for about 30 min and an aqueous solution of cobalt(II) chloride hexahydrate (1) (0.2379 g, 1.00 mmol) dissolved in 2 ml of water was added slowly and the resulting solution was refluxed for one h. The brown solution obtained was subjected to slow evaporation at room temperature and was finally triturated with toluene to recover the powdered form of the title complex. The solid product was then kept in a desiccator in order to achieve constant weight (yield 0.584 g; 87.8%).

The product was recrystallized from a mixed methanol–acetonitrile (1:9) solvent system and brown prisms of (I) were obtained. IR (KBr, cm⁻¹): 3039 (CH aromatic), 1595 (C=N aromatic), 1416–1554 (C=C aromatic), 491 and 409 (Co—N symmetric and asymmetric bending, respectively). The broad band centred near 3423 cm⁻¹ can be ascribed to ν(O—H) vibrations.

Simultaneous TG/DTA measurements were carried out using a Perkin–Elmer Diamond TG/DTA analyser. A Perkin–Elmer Lambda-35 UV-visible spectrophotometer and Moriba spectrofluorimeter equipped with a 450 W xenon lamp as an excitation source were used to obtain the diffuse reflectance and photoluminescence spectra, respectively.

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The oxygen-bound H atoms were located from difference-Fourier maps and refined as riding: O—H = 0.82 (2) Å. The carbon-bound H atoms were placed in calculated positions (C—H = 0.93 Å) and were included in the refinement in the riding-model approximation, with U_iso(H) set to 1.2U_eq(C).

Table 2
Experimental details

Crystal data
Chemical formula	[Co(C₁₅H₁₀ClN₃)₂]Cl₂·4H₂O
M_r	737.31
Crystal system, space group	Tetragonal, I4₁/a
Temperature (K)	296
a, c (Å)	9.2846 (7), 38.069 (4)
V (Å³)	3281.7 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.89
Crystal size (mm)	0.35 × 0.35 × 0.30

Data collection
Diffractometer	Bruker APEXII CCD area
Absorption correction	Multi-scan (SADABS; Bruker, 2009 )
T_min, T_max	0.739, 0.765
No. of measured, independent and observed [I > 2σ(I)] reflections	12778, 2054, 1628
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.669

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.127, 1.08
No. of reflections	2054
No. of parameters	112
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.69, −0.41
Computer programs: APEX2 (Bruker, 2009), SAINT-Plus (Bruker, 2009), SHELXT2016/4 (Sheldrick, 2015a ), SHELXL2016/4 (Sheldrick, 2015b ), Mercury (Macrae et al., 2020 ).

Supporting information

CCDC reference: 1914486

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S205698902000287X/hb7878sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698902000287X/hb7878Isup2.hkl

(a) SEM image (b) EDS spectrum of the complex (3) and elemental composition of the complex (inset table). DOI: https://doi.org/10.1107/S205698902000287X/hb7878sup3.docx

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus (Bruker, 2009); program(s) used to solve structure: SHELXT2016/4 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016/4 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: SHELXL2016/4 (Sheldrick, 2015b).

Bis(4'-chloro-2,2':6',2''-terpyridyl)cobalt(II) dichloride tetrahydrate top

Crystal data top

[Co(C₁₅H₁₀ClN₃)₂]Cl₂·4H₂O	Prism
M_r = 737.31	D_x = 1.492 Mg m⁻³
Tetragonal, I4₁/a	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -I 4ad	Cell parameters from 143 reflections
a = 9.2846 (7) Å	θ = 2.1–28.4°
c = 38.069 (4) Å	µ = 0.89 mm⁻¹
V = 3281.7 (6) Å³	T = 296 K
Z = 4	Prism, brown
F(000) = 1508	0.35 × 0.35 × 0.30 mm

Data collection top

Bruker APEXII CCD area diffractometer	2054 independent reflections
Radiation source: fine-focus sealed tube	1628 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
phi and φ scans	θ_max = 28.4°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −10→12
T_min = 0.739, T_max = 0.765	k = −11→12
12778 measured reflections	l = −50→50

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.127	w = 1/[σ²(F_o²) + (0.0659P)² + 2.6119P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max < 0.001
2054 reflections	Δρ_max = 0.69 e Å⁻³
112 parameters	Δρ_min = −0.41 e Å⁻³
2 restraints

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
Co1	0.500000	0.750000	0.625000	0.03266 (18)
Cl1	0.500000	0.750000	0.45878 (2)	0.0973 (5)
Cl2	0.000000	0.250000	0.51848 (4)	0.0902 (4)
N2	0.500000	0.750000	0.57542 (6)	0.0327 (5)
N1	0.3088 (2)	0.8560 (2)	0.61590 (4)	0.0374 (4)
O1	0.1904 (3)	0.5302 (3)	0.52954 (7)	0.0799 (7)
C6	0.3905 (2)	0.8121 (2)	0.55799 (5)	0.0368 (4)
C5	0.2786 (2)	0.8709 (2)	0.58127 (5)	0.0396 (5)
C1	0.2131 (3)	0.9052 (3)	0.63940 (6)	0.0463 (5)
H1	0.233771	0.896268	0.663200	0.056*
C7	0.3886 (3)	0.8165 (3)	0.52162 (5)	0.0488 (6)
H7	0.314890	0.862669	0.509485	0.059*
C8	0.500000	0.750000	0.50418 (8)	0.0516 (9)
C2	0.0868 (3)	0.9678 (4)	0.62963 (7)	0.0616 (7)
H2	0.022044	1.000078	0.646538	0.074*
C4	0.1537 (3)	0.9336 (4)	0.56990 (7)	0.0700 (9)
H4	0.134770	0.943043	0.546016	0.084*
C3	0.0559 (3)	0.9828 (5)	0.59462 (7)	0.0816 (11)
H3	−0.029809	1.025672	0.587528	0.098*
H2O1	0.142 (3)	0.457 (2)	0.5273 (8)	0.057 (9)*
H1O1	0.151 (4)	0.589 (3)	0.5157 (8)	0.085 (13)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0358 (2)	0.0358 (2)	0.0263 (3)	0.000	0.000	0.000
Cl1	0.1200 (10)	0.1498 (13)	0.0220 (4)	0.0660 (9)	0.000	0.000
Cl2	0.1157 (11)	0.0514 (6)	0.1035 (10)	−0.0010 (6)	0.000	0.000
N2	0.0373 (12)	0.0359 (12)	0.0249 (10)	0.0001 (9)	0.000	0.000
N1	0.0424 (10)	0.0422 (10)	0.0274 (8)	0.0000 (7)	−0.0015 (7)	0.0003 (7)
O1	0.0732 (16)	0.0850 (19)	0.0814 (16)	−0.0034 (14)	0.0074 (13)	−0.0058 (15)
C6	0.0405 (11)	0.0418 (11)	0.0282 (9)	0.0017 (8)	−0.0022 (8)	−0.0011 (8)
C5	0.0408 (11)	0.0490 (12)	0.0292 (10)	0.0040 (9)	−0.0027 (8)	−0.0004 (8)
C1	0.0541 (14)	0.0557 (14)	0.0292 (10)	0.0014 (11)	0.0042 (9)	−0.0005 (9)
C7	0.0536 (14)	0.0648 (15)	0.0281 (10)	0.0148 (11)	−0.0063 (9)	−0.0012 (9)
C8	0.065 (2)	0.069 (2)	0.0210 (13)	0.0163 (17)	0.000	0.000
C2	0.0535 (15)	0.085 (2)	0.0462 (14)	0.0173 (14)	0.0114 (11)	−0.0033 (13)
C4	0.0591 (17)	0.116 (3)	0.0346 (12)	0.0347 (17)	−0.0058 (11)	−0.0014 (14)
C3	0.0580 (17)	0.135 (3)	0.0519 (16)	0.0430 (19)	−0.0035 (13)	−0.0036 (17)

Geometric parameters (Å, º) top

Co1—N2ⁱ	1.888 (2)	C6—C7	1.385 (3)
Co1—N2	1.888 (2)	C6—C5	1.471 (3)
Co1—N1	2.0591 (18)	C5—C4	1.368 (3)
Co1—N1ⁱ	2.0591 (18)	C1—C2	1.361 (4)
Co1—N1ⁱⁱ	2.0591 (18)	C1—H1	0.9300
Co1—N1ⁱⁱⁱ	2.0591 (18)	C7—C8	1.376 (3)
Cl1—C8	1.728 (3)	C7—H7	0.9300
N2—C6	1.344 (2)	C8—C7ⁱⁱⁱ	1.376 (3)
N2—C6ⁱⁱⁱ	1.344 (2)	C2—C3	1.370 (4)
N1—C1	1.341 (3)	C2—H2	0.9300
N1—C5	1.355 (3)	C4—C3	1.385 (4)
O1—H2O1	0.824 (18)	C4—H4	0.9300
O1—H1O1	0.843 (18)	C3—H3	0.9300

N2ⁱ—Co1—N2	180.0	N2—C6—C5	113.33 (18)
N2ⁱ—Co1—N1	99.69 (5)	C7—C6—C5	125.58 (19)
N2—Co1—N1	80.31 (5)	N1—C5—C4	121.8 (2)
N2ⁱ—Co1—N1ⁱ	80.31 (5)	N1—C5—C6	113.71 (18)
N2—Co1—N1ⁱ	99.69 (5)	C4—C5—C6	124.48 (19)
N1—Co1—N1ⁱ	91.623 (15)	N1—C1—C2	122.3 (2)
N2ⁱ—Co1—N1ⁱⁱ	80.31 (5)	N1—C1—H1	118.8
N2—Co1—N1ⁱⁱ	99.69 (5)	C2—C1—H1	118.8
N1—Co1—N1ⁱⁱ	91.623 (15)	C8—C7—C6	117.3 (2)
N1ⁱ—Co1—N1ⁱⁱ	160.62 (9)	C8—C7—H7	121.3
N2ⁱ—Co1—N1ⁱⁱⁱ	99.69 (5)	C6—C7—H7	121.3
N2—Co1—N1ⁱⁱⁱ	80.31 (5)	C7ⁱⁱⁱ—C8—C7	122.3 (3)
N1—Co1—N1ⁱⁱⁱ	160.62 (9)	C7ⁱⁱⁱ—C8—Cl1	118.85 (14)
N1ⁱ—Co1—N1ⁱⁱⁱ	91.623 (16)	C7—C8—Cl1	118.86 (14)
N1ⁱⁱ—Co1—N1ⁱⁱⁱ	91.623 (15)	C1—C2—C3	119.3 (2)
C6—N2—C6ⁱⁱⁱ	120.8 (2)	C1—C2—H2	120.4
C6—N2—Co1	119.59 (12)	C3—C2—H2	120.4
C6ⁱⁱⁱ—N2—Co1	119.60 (12)	C5—C4—C3	118.7 (2)
C1—N1—C5	118.49 (19)	C5—C4—H4	120.6
C1—N1—Co1	128.45 (15)	C3—C4—H4	120.6
C5—N1—Co1	113.02 (14)	C2—C3—C4	119.4 (3)
H2O1—O1—H1O1	103 (3)	C2—C3—H3	120.3
N2—C6—C7	121.1 (2)	C4—C3—H3	120.3

N1—Co1—N2—C6	0.56 (12)	N2—C6—C5—N1	2.1 (3)
N1ⁱ—Co1—N2—C6	−89.44 (12)	C7—C6—C5—N1	−178.2 (2)
N1ⁱⁱ—Co1—N2—C6	90.56 (12)	N2—C6—C5—C4	−177.1 (3)
N1ⁱⁱⁱ—Co1—N2—C6	−179.44 (12)	C7—C6—C5—C4	2.6 (4)
N1—Co1—N2—C6ⁱⁱⁱ	−179.44 (12)	C5—N1—C1—C2	0.7 (4)
N1ⁱ—Co1—N2—C6ⁱⁱⁱ	90.56 (12)	Co1—N1—C1—C2	−176.8 (2)
N1ⁱⁱ—Co1—N2—C6ⁱⁱⁱ	−89.44 (12)	N2—C6—C7—C8	2.5 (3)
N1ⁱⁱⁱ—Co1—N2—C6ⁱⁱⁱ	0.56 (12)	C5—C6—C7—C8	−177.14 (19)
C6ⁱⁱⁱ—N2—C6—C7	−1.31 (17)	C6—C7—C8—C7ⁱⁱⁱ	−1.23 (15)
Co1—N2—C6—C7	178.69 (16)	C6—C7—C8—Cl1	178.78 (15)
C6ⁱⁱⁱ—N2—C6—C5	178.4 (2)	N1—C1—C2—C3	−0.7 (5)
Co1—N2—C6—C5	−1.6 (2)	N1—C5—C4—C3	−0.1 (5)
C1—N1—C5—C4	−0.4 (4)	C6—C5—C4—C3	179.0 (3)
Co1—N1—C5—C4	177.5 (2)	C1—C2—C3—C4	0.2 (6)
C1—N1—C5—C6	−179.6 (2)	C5—C4—C3—C2	0.1 (6)
Co1—N1—C5—C6	−1.7 (2)

Symmetry codes: (i) y−1/4, −x+5/4, −z+5/4; (ii) −y+5/4, x+1/4, −z+5/4; (iii) −x+1, −y+3/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H2O1···Cl2	0.82	2.35	3.1735	177
O1—H1O1···Cl2^iv	0.84	2.43	3.2607	170
C7—H7···O1^v	0.93	2.44	3.334 (4)	161

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

Acknowledgements

The authors thank Tumkur University administration for their support and encouragement. BT is thankful to the Principal and the staff of Government Science College, Chithradurga-577501.

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