1-Ethyl-4-hydroxy-2,6-dimethyl­pyridinium bromide dihydrate

Seethalakshmi, T.; Manivannan, S.; Lynch, D.E.; Dhanuskodi, S.; Kaliannan, P.

doi:10.1107/S1600536807000232

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 63| Part 2| February 2007| Pages o599-o601

https://doi.org/10.1107/S1600536807000232

1-Ethyl-4-hydroxy-2,6-dimethylpyridinium bromide dihydrate

T. Seethalakshmi,^a S. Manivannan,^a Daniel E. Lynch,^b S. Dhanuskodi ^a and P. Kaliannan ^a ^*

^aSchool of Physics, Bharathidasan University, Tiruchirappalli 620 024, India, and ^bFaculty of Health and Life Sciences, Coventry University, Coventry, CV1 5FB, UK
^*Correspondence e-mail: kal_44in@yahoo.co.in

(Received 8 December 2006; accepted 3 January 2007; online 12 January 2007)

The title compound, C₉H₁₄NO⁺Br⁻·2H₂O, comprises 1-ethyl-2,6-dimethyl-4-hydroxypyridinium cations and bromide anions, with two solvent water molecules per formula unit. In the crystal structure, the anions, cations and water molecules are linked via intermolecular O—H⋯Br and O—H⋯O hydrogen bonds, forming layers parallel to the (100) plane.

Comment

2,6-Dimethyl-4-hydroxypyridinone and 4-hydroxypyridinium salts have attracted much attention in the field of non-linear optics (NLO), since the 4-hydroxypyridinium conjugated electronic system could be an interesting hyperpolarizable chromophore for NLO activity (Manivannan et al., 2004 ; Dhanuskodi et al., 2006 ). To achieve self-assembly of organic cations in the manner required to exhibit NLO activity (Tamuly et al., 2005 ), suitable anions must be identified and used effectively. Halide anions have been reported to improve the physicochemical stability of 1-ethyl-2,6-dimethyl-4-(1H)-pyridinones (Dhanuskodi et al., 2006). We report here the crystal structure of 1-ethyl-2,6-dimethyl-4-hydroxypyridinium bromide dihydrate (EDMPBr·2H₂O), (I).

The crystal structure of (I) (Fig. 1) comprises 1-ethyl-2,6-dimethyl-4-hydroxypyridinium cations and bromide anions, with two solvent water molecules per formula unit. The C2—N1—C6 bond angle in the cation [120.71 (16)°] is comparable to that in 2,6-dimethylpyridine (Bond & Davies, 2001 ) and the 2,6-dimethylpyridine-urea complex (Lee & Wallwork, 1965 ). The organic cations lie in layers parallel to the (100) plane (Fig. 2). The bromide anions and water molecules lie between these layers, forming hydrogen-bonded sheets via O—H⋯O and O—H⋯Br interactions (Fig. 3 and Table 1). Two distinct ring motifs exist within these sheets, with graph-set descriptors R₄⁶(12) and R₁₀⁶(20) (Bernstein et al., 1995 ). O—H⋯O hydrogen bonds are formed between atom O1 of the hydroxyl group of the organic cation and one of the solvent water molecules (Fig. 2 and Table 1).

Figure 1
The molecular structure of (I)

, showing displacement ellipsoids drawn at the 50% probability level. H atoms are represented by circles of arbitrary radius.

Figure 2
View of (I)

along b, showing layers of organic cations lying parallel to the (100) plane, with Br⁻ anions and water molecules lying between them. Dashed lines indicate hydrogen bonds. H atoms not involved in hydrogen bonding have been omitted.

Figure 3
A single Br⁻/H₂O sheet viewed along the a-axis direction, showing O—H⋯O and O—H⋯Br hydrogen bonds (dashed lines).

Experimental

The title compound was synthesized by dissolving 1-ethyl-2,6-dimethyl-4(1H)-pyridinone trihydrate (EDMP·3H₂O, 1.51 g) with HBr (2.43 g) in distilled water (5 ml). The solution was stirred well at room temperature for 7 h and the solvent was allowed to evaporate at 323 K. The residual crystalline powder was redissolved in distilled water, and single crystals of (I) were obtained by slow evaporation at 303 K.

Crystal data

C₉H₁₄NO⁺Br⁻·2H₂O
M_r = 268.15
Monoclinic, P 2₁ /c
a = 10.5747 (3) Å
b = 8.0382 (1) Å
c = 15.0377 (4) Å
β = 109.298 (1)°
V = 1206.41 (5) Å³
Z = 4
D_x = 1.476 Mg m⁻³
Mo Kα radiation
μ = 3.39 mm⁻¹
T = 120 (2) K
Block, colourless
0.54 × 0.48 × 0.12 mm

Data collection

Nonius KappaCCD diffractometer
φ and ω scans
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.176, T_max = 0.666
15899 measured reflections
2768 independent reflections
2455 reflections with I > 2σ(I)
R_int = 0.033
θ_max = 27.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.021
wR(F²) = 0.052
S = 1.04
2768 reflections
131 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0208P)² + 0.702P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.52 e Å⁻³
Extinction correction: SHELXL
Extinction coefficient: 0.0104 (6)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O1Wⁱ	0.80	1.78	2.5720 (16)	173
O1W—H11⋯O2W	0.82	1.90	2.7135 (16)	175
O1W—H12⋯Br1ⁱⁱ	0.76	2.50	3.2610 (12)	172
O2W—H21⋯Br1	0.81	2.52	3.3332 (12)	178
O2W—H22⋯Br1ⁱⁱⁱ	0.79	2.52	3.3061 (12)	173
Symmetry codes: (i) -x+1, -y+1, -z; (ii) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (iii) $[-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

H atoms, except those of the water molecules, were positioned geometrically with C—H = 0.93 (CH), 0.96 (CH₃) or 0.97 Å (CH₂), and with O—H = 0.80 Å. They were then refined as riding, with U_iso(H) = 1.2U_eq(C,O) or 1.5U_eq(methyl C). H atoms of the water molecules were found in difference Fourier maps and refined initially with a restrained geometry. In the final cycles of refinement, they were made to ride on their parent O atoms, with U_iso(H) = 1.2U_eq(O).

Data collection: COLLECT (Nonius, 1998 ); cell refinement: DENZO (Otwinowski & Minor, 1997 ); data reduction: DENZO; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ) and PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97 and PARST (Nardelli 1995 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536807000232/bi2126sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807000232/bi2126Isup2.hkl

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PARST (Nardelli 1995).

(I) top

Crystal data top

C₉H₁₄NO⁺Br⁻·2H₂O	F(000) = 552
M_r = 268.15	D_x = 1.476 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2935 reflections
a = 10.5747 (3) Å	θ = 1.0–27.5°
b = 8.0382 (1) Å	µ = 3.39 mm⁻¹
c = 15.0377 (4) Å	T = 120 K
β = 109.298 (1)°	Block, colourless
V = 1206.41 (5) Å³	0.54 × 0.48 × 0.12 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	2768 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2455 reflections with I > 2σ(I)
10 cm confocal mirrors monochromator	R_int = 0.033
φ and ω scans	θ_max = 27.5°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −13→13
T_min = 0.176, T_max = 0.666	k = −10→10
15899 measured reflections	l = −19→19

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.021	H-atom parameters constrained
wR(F²) = 0.052	w = 1/[σ²(F_o²) + (0.0208P)² + 0.702P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max = 0.001
2768 reflections	Δρ_max = 0.30 e Å⁻³
131 parameters	Δρ_min = −0.52 e Å⁻³
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0104 (6)

Special details top

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.53552 (11)	0.11597 (15)	−0.12166 (8)	0.0210 (3)
H1	0.6082	0.1578	−0.1037	0.025*
N1	0.30377 (13)	0.25353 (16)	0.03692 (9)	0.0151 (3)
C2	0.25160 (15)	0.15705 (19)	−0.04183 (11)	0.0164 (3)
C3	0.33045 (16)	0.11197 (19)	−0.09427 (11)	0.0167 (3)
H3	0.2949	0.0458	−0.1474	0.020*
C4	0.46300 (16)	0.16421 (19)	−0.06866 (11)	0.0159 (3)
C5	0.51367 (15)	0.26305 (19)	0.01139 (11)	0.0162 (3)
H5	0.6019	0.2999	0.0295	0.019*
C6	0.43404 (15)	0.30649 (19)	0.06379 (11)	0.0162 (3)
C7	0.49030 (18)	0.4105 (2)	0.15046 (13)	0.0242 (4)
H7A	0.5830	0.4336	0.1602	0.036*
H7B	0.4825	0.3515	0.2039	0.036*
H7C	0.4415	0.5132	0.1428	0.036*
C8	0.21871 (17)	0.2994 (2)	0.09484 (12)	0.0203 (3)
H8A	0.1264	0.3101	0.0541	0.024*
H8B	0.2474	0.4065	0.1243	0.024*
C9	0.22680 (19)	0.1707 (2)	0.17072 (13)	0.0252 (4)
H9A	0.2006	0.0639	0.1419	0.038*
H9B	0.1678	0.2021	0.2046	0.038*
H9C	0.3171	0.1648	0.2135	0.038*
C10	0.10880 (16)	0.1013 (2)	−0.07030 (13)	0.0241 (4)
H1A	0.0942	0.0425	−0.0190	0.036*
H1B	0.0897	0.0292	−0.1240	0.036*
H1C	0.0509	0.1966	−0.0861	0.036*
O1W	0.22566 (12)	0.76473 (15)	0.07413 (9)	0.0252 (3)
H11	0.2091	0.7218	0.1186	0.030*
H12	0.1964	0.7154	0.0286	0.030*
O2W	0.15723 (11)	0.63640 (15)	0.21883 (8)	0.0221 (3)
H21	0.1498	0.7078	0.2552	0.027*
H22	0.0903	0.5849	0.2026	0.027*
Br1	0.123005 (16)	0.92168 (2)	0.370123 (12)	0.02309 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0193 (6)	0.0291 (6)	0.0176 (6)	−0.0035 (5)	0.0102 (5)	−0.0053 (5)
N1	0.0185 (6)	0.0149 (6)	0.0138 (7)	0.0036 (5)	0.0079 (5)	0.0023 (5)
C2	0.0168 (7)	0.0171 (7)	0.0136 (8)	0.0022 (6)	0.0029 (6)	0.0045 (6)
C3	0.0193 (8)	0.0177 (7)	0.0121 (8)	−0.0003 (6)	0.0038 (6)	0.0002 (6)
C4	0.0189 (8)	0.0164 (7)	0.0137 (8)	0.0025 (6)	0.0072 (6)	0.0024 (6)
C5	0.0164 (7)	0.0182 (8)	0.0141 (8)	−0.0018 (6)	0.0051 (6)	0.0009 (6)
C6	0.0191 (8)	0.0141 (7)	0.0149 (8)	0.0008 (6)	0.0048 (6)	0.0021 (6)
C7	0.0297 (9)	0.0252 (9)	0.0193 (9)	−0.0042 (7)	0.0100 (7)	−0.0056 (7)
C8	0.0238 (8)	0.0200 (8)	0.0225 (9)	0.0047 (7)	0.0148 (7)	0.0013 (7)
C9	0.0330 (10)	0.0243 (9)	0.0243 (10)	0.0016 (7)	0.0177 (8)	0.0025 (7)
C10	0.0166 (8)	0.0306 (9)	0.0245 (10)	−0.0001 (7)	0.0060 (7)	0.0021 (7)
O1W	0.0263 (6)	0.0302 (6)	0.0224 (7)	−0.0068 (5)	0.0125 (5)	−0.0044 (5)
O2W	0.0223 (6)	0.0229 (6)	0.0212 (6)	−0.0018 (5)	0.0071 (5)	−0.0026 (5)
Br1	0.02279 (10)	0.02429 (11)	0.02064 (11)	0.00401 (7)	0.00508 (7)	−0.00067 (7)

Geometric parameters (Å, º) top

O1—C4	1.3332 (18)	C7—H7C	0.960
O1—H1	0.800	C8—C9	1.522 (2)
N1—C6	1.369 (2)	C8—H8A	0.970
N1—C2	1.370 (2)	C8—H8B	0.970
N1—C8	1.4905 (19)	C9—H9A	0.960
C2—C3	1.372 (2)	C9—H9B	0.960
C2—C10	1.496 (2)	C9—H9C	0.960
C3—C4	1.390 (2)	C10—H1A	0.960
C3—H3	0.930	C10—H1B	0.960
C4—C5	1.393 (2)	C10—H1C	0.960
C5—C6	1.375 (2)	O1W—H11	0.821
C5—H5	0.930	O1W—H12	0.763
C6—C7	1.496 (2)	O2W—H21	0.815
C7—H7A	0.960	O2W—H22	0.786
C7—H7B	0.960

C4—O1—H1	110.7	H7A—C7—H7C	109.5
C6—N1—C2	120.65 (13)	H7B—C7—H7C	109.5
C6—N1—C8	119.56 (13)	N1—C8—C9	112.01 (13)
C2—N1—C8	119.79 (13)	N1—C8—H8A	109.2
N1—C2—C3	119.91 (14)	C9—C8—H8A	109.2
N1—C2—C10	119.81 (14)	N1—C8—H8B	109.2
C3—C2—C10	120.28 (15)	C9—C8—H8B	109.2
C2—C3—C4	120.64 (15)	H8A—C8—H8B	107.9
C2—C3—H3	119.7	C8—C9—H9A	109.5
C4—C3—H3	119.7	C8—C9—H9B	109.5
O1—C4—C3	118.23 (14)	H9A—C9—H9B	109.5
O1—C4—C5	123.32 (14)	C8—C9—H9C	109.5
C3—C4—C5	118.44 (14)	H9A—C9—H9C	109.5
C6—C5—C4	120.43 (14)	H9B—C9—H9C	109.5
C6—C5—H5	119.8	C2—C10—H1A	109.5
C4—C5—H5	119.8	C2—C10—H1B	109.5
N1—C6—C5	119.93 (14)	H1A—C10—H1B	109.5
N1—C6—C7	120.17 (14)	C2—C10—H1C	109.5
C5—C6—C7	119.90 (14)	H1A—C10—H1C	109.5
C6—C7—H7A	109.5	H1B—C10—H1C	109.5
C6—C7—H7B	109.5	H11—O1W—H12	112.4
H7A—C7—H7B	109.5	H21—O2W—H22	107.6
C6—C7—H7C	109.5

C6—N1—C2—C3	0.3 (2)	C3—C4—C5—C6	0.4 (2)
C8—N1—C2—C3	−178.74 (14)	C2—N1—C6—C5	0.1 (2)
C6—N1—C2—C10	−179.64 (14)	C8—N1—C6—C5	179.21 (14)
C8—N1—C2—C10	1.3 (2)	C2—N1—C6—C7	−179.43 (14)
N1—C2—C3—C4	−0.4 (2)	C8—N1—C6—C7	−0.4 (2)
C10—C2—C3—C4	179.54 (15)	C4—C5—C6—N1	−0.5 (2)
C2—C3—C4—O1	179.55 (14)	C4—C5—C6—C7	179.06 (15)
C2—C3—C4—C5	0.1 (2)	C6—N1—C8—C9	−90.24 (18)
O1—C4—C5—C6	−179.05 (14)	C2—N1—C8—C9	88.85 (18)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O1Wⁱ	0.80	1.78	2.5720 (16)	173
O1W—H11···O2W	0.82	1.90	2.7135 (16)	175
O1W—H12···Br1ⁱⁱ	0.76	2.50	3.2610 (12)	172
O2W—H21···Br1	0.81	2.52	3.3332 (12)	178
O2W—H22···Br1ⁱⁱⁱ	0.79	2.52	3.3061 (12)	173

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

Acknowledgements

The authors thank the EPSRC National Crystallography Service (University of Southampton, UK) for the X-ray data collection. TS thanks Professor V. Parthasarathi, School of Physics, Bharathidasan University, for fruitful discussions.

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