2-Amino-4-methyl­pyridinium trifluoro­acetate: a monoclinic polymorph

Pourayoubi, M.; Toghraee, M.; Rheingold, A.L.; Golen, J.A.

doi:10.1107/S1600536810008408

organic compounds

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Volume 66| Part 4| April 2010| Page o844

doi:10.1107/S1600536810008408

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2-Amino-4-methylpyridinium trifluoroacetate: a monoclinic polymorph

Mehrdad Pourayoubi,^a ^* Maryam Toghraee,^a Arnold L. Rheingold ^b and James A. Golen ^b

^aDepartment of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779, Iran, and ^bDepartment of Chemistry, University of California, San Diego, 9500 Gilman, Drive, La Jolla, CA 92093, USA
^*Correspondence e-mail: mehrdad_pourayoubi@yahoo.com

(Received 3 March 2010; accepted 4 March 2010; online 17 March 2010)

The title salt, C₆H₉N₂⁺·C₂F₃O₂⁻, is a monoclinic polymorph of a previously reported structure [Hemamalini & Fun (2010). Acta Cryst. E66, o781–o782]. In the crystal structure, the cations and anions are linked by two different types of N—H⋯O hydrogen bonds, forming cation–anion pairs. These pairs are hydrogen bonded to neighbouring pairs via another N—H⋯O hydrogen bonds involving an H atom of the NH₂ group and one of the O atoms of the COO⁻ group into a chain extended along the b axis.

Related literature

For a related structure and the triclinic polymorph of the title salt, see: Hemamalini & Fun (2010a ,b ).

Experimental

Crystal data

C₆H₉N₂⁺·C₂F₃O₂⁻
M_r = 222.17
Monoclinic, P 2₁ /c
a = 8.5315 (7) Å
b = 11.4901 (9) Å
c = 9.7206 (8) Å
β = 90.820 (1)°
V = 952.79 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.15 mm⁻¹
T = 100 K
0.30 × 0.20 × 0.10 mm

Data collection

Bruker SMART APEX diffractometer
10752 measured reflections
2197 independent reflections
1784 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.035
wR(F²) = 0.098
S = 1.06
2197 reflections
150 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O2	0.952 (19)	1.82 (2)	2.7724 (14)	177.4 (18)
N2—H2C⋯O1	0.901 (18)	1.938 (19)	2.8376 (15)	176.3 (17)
N2—H2B⋯O2ⁱ	0.923 (18)	2.055 (18)	2.8946 (15)	150.5 (15)
Symmetry code: (i) $[-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: SMART (Bruker, 2005 ); cell refinement: SAINT (Bruker 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810008408/ng2740sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810008408/ng2740Isup2.hkl

checkCIF report

Comment top

In the previous works, the structure determinations of 2-aminopyridinium trifluoroacetate and the triclinic polymorph of 2-amino-4-methylpyridinium trifluoroacetate (Hemamalini & Fun, 2010a,b) have been investigated; we report here on the crystal structure of title compound, 4-methyl-2-aminopyridinium trifluoroacetate (Fig. 1). The cation and anion are linked by two different types of N—H···O hydrogen bonds, forming the cation-anion pair. The pairs are hydrogen bonded to neighbouring pairs via another N—H···O hydrogen bonds between the hydrogen of NH₂ moiety and one of the oxygen atom of COO^- group into chain extended along the b axis (Fig. 2).

Related literature top

For a related structure and the triclinic polymorph of the title salt, see: Hemamalini & Fun (2010a,b).

Experimental top

The title compound was obtained accidently from the reaction between 2,2,2-trifluoroacetamide, phosphorus pentachloride and formic acid and then the treatment of 2-amino-4-methylpyridine and triethylamine. The crystal was obtained from chloroform and n-heptane at room temperature.

Computing details top

Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker 2005); data reduction: SAINT (Bruker 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title salt, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50 % probability level.
	Fig. 2. A view of crystal packing along the b axis, hydrogen bonds are shown by dashed lines.

2-Amino-4-methylpyridinium trifluoroacetate top

Crystal data top

C₆H₉N₂⁺·C₂F₃O₂⁻	F(000) = 456
M_r = 222.17	D_x = 1.549 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5265 reflections
a = 8.5315 (7) Å	θ = 2.7–28.0°
b = 11.4901 (9) Å	µ = 0.15 mm⁻¹
c = 9.7206 (8) Å	T = 100 K
β = 90.820 (1)°	Block, colorless
V = 952.79 (13) Å³	0.30 × 0.20 × 0.10 mm
Z = 4

Data collection top

Bruker SMART APEX diffractometer	1784 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.036
Graphite monochromator	θ_max = 28.2°, θ_min = 2.4°
ϕ and ω scans	h = −5→11
10752 measured reflections	k = −14→14
2197 independent reflections	l = −12→12

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)] = 0.035	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.098	w = 1/[σ²(F_o²) + (0.0474P)² + 0.2454P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max = 0.001
2197 reflections	Δρ_max = 0.29 e Å⁻³
150 parameters	Δρ_min = −0.23 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0084 (16)

Crystal data top

C₆H₉N₂⁺·C₂F₃O₂⁻	V = 952.79 (13) Å³
M_r = 222.17	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.5315 (7) Å	µ = 0.15 mm⁻¹
b = 11.4901 (9) Å	T = 100 K
c = 9.7206 (8) Å	0.30 × 0.20 × 0.10 mm
β = 90.820 (1)°

Data collection top

Bruker SMART APEX diffractometer	1784 reflections with I > 2σ(I)
10752 measured reflections	R_int = 0.036
2197 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.035	0 restraints
wR(F²) = 0.098	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	Δρ_max = 0.29 e Å⁻³
2197 reflections	Δρ_min = −0.23 e Å⁻³
150 parameters

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.

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
F1	0.16929 (11)	0.27679 (7)	1.06142 (10)	0.0350 (2)
F2	0.08357 (10)	0.40806 (8)	0.92121 (10)	0.0358 (2)
F3	0.25375 (10)	0.45302 (7)	1.07851 (9)	0.0316 (2)
O1	0.36035 (11)	0.23798 (8)	0.85540 (11)	0.0259 (2)
O2	0.41240 (11)	0.42938 (8)	0.83832 (10)	0.0257 (2)
N1	0.61429 (13)	0.37742 (9)	0.62595 (12)	0.0212 (2)
H1B	0.544 (2)	0.3930 (17)	0.699 (2)	0.048 (5)*
N2	0.56684 (13)	0.18015 (10)	0.63958 (12)	0.0223 (3)
H2C	0.504 (2)	0.1964 (16)	0.711 (2)	0.040 (5)*
H2B	0.588 (2)	0.1040 (16)	0.6158 (18)	0.034 (5)*
C1	0.68436 (16)	0.47274 (12)	0.56989 (15)	0.0251 (3)
H1A	0.6618	0.5480	0.6049	0.030*
C2	0.78596 (16)	0.46100 (12)	0.46475 (15)	0.0250 (3)
H2A	0.8341	0.5277	0.4261	0.030*
C3	0.81986 (15)	0.34848 (12)	0.41287 (14)	0.0214 (3)
C4	0.74763 (14)	0.25417 (11)	0.47012 (13)	0.0206 (3)
H4A	0.7689	0.1784	0.4359	0.025*
C5	0.64122 (14)	0.26797 (11)	0.58005 (14)	0.0196 (3)
C6	0.93335 (16)	0.33574 (13)	0.29694 (15)	0.0260 (3)
H6A	0.9287	0.2560	0.2612	0.039*
H6B	1.0398	0.3523	0.3307	0.039*
H6C	0.9055	0.3905	0.2233	0.039*
C7	0.34308 (14)	0.34184 (11)	0.88424 (14)	0.0200 (3)
C8	0.21258 (15)	0.36940 (11)	0.98849 (15)	0.0236 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.0412 (5)	0.0257 (5)	0.0385 (5)	−0.0036 (4)	0.0209 (4)	0.0027 (4)
F2	0.0220 (4)	0.0367 (5)	0.0488 (6)	0.0070 (3)	0.0017 (4)	−0.0026 (4)
F3	0.0328 (5)	0.0271 (5)	0.0350 (5)	−0.0012 (3)	0.0096 (4)	−0.0114 (4)
O1	0.0294 (5)	0.0168 (5)	0.0319 (6)	−0.0008 (4)	0.0099 (4)	−0.0027 (4)
O2	0.0292 (5)	0.0179 (5)	0.0303 (6)	−0.0033 (4)	0.0105 (4)	0.0005 (4)
N1	0.0223 (5)	0.0177 (5)	0.0237 (6)	0.0006 (4)	0.0044 (4)	−0.0015 (5)
N2	0.0250 (6)	0.0168 (6)	0.0253 (6)	−0.0007 (4)	0.0073 (5)	−0.0007 (5)
C1	0.0272 (7)	0.0168 (6)	0.0314 (8)	−0.0007 (5)	0.0026 (6)	−0.0014 (5)
C2	0.0250 (7)	0.0200 (7)	0.0302 (8)	−0.0033 (5)	0.0032 (5)	0.0040 (5)
C3	0.0181 (6)	0.0239 (7)	0.0223 (7)	−0.0005 (5)	0.0013 (5)	0.0008 (5)
C4	0.0206 (6)	0.0187 (6)	0.0224 (7)	0.0006 (5)	0.0019 (5)	−0.0010 (5)
C5	0.0185 (6)	0.0181 (6)	0.0221 (6)	0.0003 (4)	−0.0005 (5)	−0.0005 (5)
C6	0.0236 (7)	0.0298 (7)	0.0247 (7)	−0.0021 (5)	0.0052 (5)	0.0023 (6)
C7	0.0200 (6)	0.0185 (6)	0.0217 (7)	−0.0005 (5)	0.0022 (5)	−0.0010 (5)
C8	0.0227 (6)	0.0182 (6)	0.0299 (7)	−0.0008 (5)	0.0060 (5)	−0.0015 (5)

Geometric parameters (Å, º) top

F1—C8	1.3337 (15)	C1—H1A	0.9500
F2—C8	1.3475 (16)	C2—C3	1.4190 (19)
F3—C8	1.3429 (16)	C2—H2A	0.9500
O1—C7	1.2352 (15)	C3—C4	1.3688 (18)
O2—C7	1.2523 (15)	C3—C6	1.5033 (18)
N1—C5	1.3552 (16)	C4—C5	1.4209 (17)
N1—C1	1.3650 (17)	C4—H4A	0.9500
N1—H1B	0.952 (19)	C6—H6A	0.9800
N2—C5	1.3290 (16)	C6—H6B	0.9800
N2—H2C	0.901 (18)	C6—H6C	0.9800
N2—H2B	0.923 (18)	C7—C8	1.5490 (18)
C1—C2	1.356 (2)

C5—N1—C1	122.40 (12)	N2—C5—N1	118.49 (12)
C5—N1—H1B	122.1 (12)	N2—C5—C4	123.85 (12)
C1—N1—H1B	115.5 (12)	N1—C5—C4	117.67 (12)
C5—N2—H2C	118.0 (12)	C3—C6—H6A	109.5
C5—N2—H2B	121.1 (11)	C3—C6—H6B	109.5
H2C—N2—H2B	120.5 (16)	H6A—C6—H6B	109.5
C2—C1—N1	120.62 (12)	C3—C6—H6C	109.5
C2—C1—H1A	119.7	H6A—C6—H6C	109.5
N1—C1—H1A	119.7	H6B—C6—H6C	109.5
C1—C2—C3	119.61 (12)	O1—C7—O2	129.54 (12)
C1—C2—H2A	120.2	O1—C7—C8	115.80 (11)
C3—C2—H2A	120.2	O2—C7—C8	114.62 (11)
C4—C3—C2	118.79 (12)	F1—C8—F3	107.24 (12)
C4—C3—C6	121.75 (12)	F1—C8—F2	106.89 (11)
C2—C3—C6	119.46 (12)	F3—C8—F2	106.54 (10)
C3—C4—C5	120.90 (12)	F1—C8—C7	113.06 (11)
C3—C4—H4A	119.5	F3—C8—C7	112.88 (11)
C5—C4—H4A	119.5	F2—C8—C7	109.85 (11)

C5—N1—C1—C2	−0.3 (2)	C3—C4—C5—N2	179.68 (13)
N1—C1—C2—C3	−0.1 (2)	C3—C4—C5—N1	−0.10 (19)
C1—C2—C3—C4	0.5 (2)	O1—C7—C8—F1	18.42 (18)
C1—C2—C3—C6	−179.60 (13)	O2—C7—C8—F1	−163.72 (12)
C2—C3—C4—C5	−0.37 (19)	O1—C7—C8—F3	140.38 (12)
C6—C3—C4—C5	179.73 (12)	O2—C7—C8—F3	−41.76 (17)
C1—N1—C5—N2	−179.33 (12)	O1—C7—C8—F2	−100.87 (14)
C1—N1—C5—C4	0.46 (19)	O2—C7—C8—F2	76.99 (14)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2	0.952 (19)	1.82 (2)	2.7724 (14)	177.4 (18)
N2—H2C···O1	0.901 (18)	1.938 (19)	2.8376 (15)	176.3 (17)
N2—H2B···O2ⁱ	0.923 (18)	2.055 (18)	2.8946 (15)	150.5 (15)

Symmetry code: (i) −x+1, y−1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₆H₉N₂⁺·C₂F₃O₂⁻
M_r	222.17
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	8.5315 (7), 11.4901 (9), 9.7206 (8)
β (°)	90.820 (1)
V (Å³)	952.79 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.15
Crystal size (mm)	0.30 × 0.20 × 0.10

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	10752, 2197, 1784
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.664

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.098, 1.06
No. of reflections	2197
No. of parameters	150
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.29, −0.23

Computer programs: SMART (Bruker, 2005), SAINT (Bruker 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2	0.952 (19)	1.82 (2)	2.7724 (14)	177.4 (18)
N2—H2C···O1	0.901 (18)	1.938 (19)	2.8376 (15)	176.3 (17)
N2—H2B···O2ⁱ	0.923 (18)	2.055 (18)	2.8946 (15)	150.5 (15)

Symmetry code: (i) −x+1, y−1/2, −z+3/2.

Acknowledgements

Support of this investigation by Ferdowsi University of Mashhad is gratefully acknowledged.

References

Bruker (2005). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Hemamalini, M. & Fun, H.-K. (2010a). Acta Cryst. E66, o691–o692. Web of Science CSD CrossRef IUCr Journals Google Scholar
Hemamalini, M. & Fun, H.-K. (2010b). Acta Cryst. E66, o781–o782. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef IUCr Journals Google Scholar