Two anilinium salts: anilinium hydrogenphosphite and anilinium hydrogenoxalate hemihydrate

In the title compounds, C₆H₅NH₃⁺·H₂PO₃^- and C₆H₅NH₃⁺·C₂HO₄^-·0.5H₂O, the NH₃⁺ groups of the anilinium ion are ordered at room temperature. The rotation of these groups along the N-C_aryl bond, which is often observed at room temperature in other anilinium compounds, is prevented by hydrogen bonds between the NH₃⁺ group and the anions. In both compounds, the geometry of the cation is significantly distorted from D_6h to a symmetry close to C_2v. The angle ipso to the substituent is significantly larger than 120°, as expected from the [sigma]-electron-withdrawing character of the NH₃⁺ group.

Computing details

For both compounds, data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

(I) Anilinium hydrogenphosphite

Crystal data

C6H8N^+·H2PO3^−	F(000) = 368
Mr = 175.12	Dx = 1.409 Mg m^−3
Monoclinic, P21/a	Mo Kα radiation, λ = 0.71073 Å
a = 6.216 (2) Å	Cell parameters from 25 reflections
b = 14.219 (6) Å	θ = 9.7–15.2°
c = 9.342 (3) Å	µ = 0.29 mm^−1
β = 90.91 (3)°	T = 293 K
V = 825.6 (5) Å^3	Prism, colourless
Z = 4	0.34 × 0.34 × 0.34 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.023
Radiation source: fine-focus sealed tube	θmax = 26.0°, θmin = 3.6°
Graphite monochromator	h = −7→7
profile data from ω–2θ scans	k = 0→17
3607 measured reflections	l = −11→11
1612 independent reflections	3 standard reflections every 180 min
1221 reflections with I > 2σ(I)	intensity decay: 1%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.028	All H-atom parameters refined
wR(F^2) = 0.084	w = 1/[σ^2(Fo^2) + (0.038P)^2 + 0.3216P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1612 reflections	Δρmax = 0.25 e Å^−3
140 parameters	Δρmin = −0.25 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.015 (2)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
P1	0.03258 (8)	0.36864 (3)	0.40048 (5)	0.03614 (17)
H1	−0.022 (3)	0.3043 (14)	0.491 (2)	0.048 (6)*
O1	0.1077 (2)	0.32294 (10)	0.26648 (14)	0.0448 (4)
O2	−0.1538 (2)	0.43441 (10)	0.38316 (16)	0.0503 (4)
O3	0.2302 (2)	0.41784 (12)	0.47158 (17)	0.0564 (5)
H8	0.196 (5)	0.464 (2)	0.519 (3)	0.085*
C1	0.0613 (3)	0.12860 (12)	0.04184 (18)	0.0335 (4)
C2	0.2505 (3)	0.09411 (16)	−0.0102 (2)	0.0466 (5)
H2	0.360 (4)	0.0804 (17)	0.054 (3)	0.061 (7)*
C3	0.2716 (4)	0.08397 (19)	−0.1567 (3)	0.0584 (6)
H3	0.401 (4)	0.0613 (18)	−0.190 (3)	0.072 (8)*
C4	0.1064 (4)	0.10847 (18)	−0.2485 (3)	0.0601 (6)
H4	0.121 (4)	0.101 (2)	−0.349 (3)	0.074 (8)*
C5	−0.0816 (4)	0.14348 (19)	−0.1948 (2)	0.0607 (6)
H5	−0.201 (5)	0.162 (2)	−0.260 (3)	0.083 (9)*
C6	−0.1051 (4)	0.15338 (16)	−0.0487 (2)	0.0482 (5)
H6	−0.234 (4)	0.1749 (18)	−0.012 (3)	0.060 (7)*
N	0.0369 (3)	0.14186 (13)	0.19561 (17)	0.0369 (4)
H7A	0.133 (4)	0.1060 (17)	0.253 (3)	0.055 (6)*
H7B	−0.097 (4)	0.1337 (17)	0.218 (3)	0.057 (7)*
H7C	0.071 (4)	0.2033 (19)	0.222 (3)	0.060 (7)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0381 (3)	0.0390 (3)	0.0314 (2)	0.0007 (2)	0.00316 (17)	−0.0048 (2)
O1	0.0461 (8)	0.0472 (8)	0.0411 (8)	−0.0013 (6)	0.0051 (6)	−0.0141 (6)
O2	0.0365 (7)	0.0567 (9)	0.0575 (9)	0.0059 (6)	−0.0077 (6)	−0.0239 (7)
O3	0.0450 (9)	0.0612 (10)	0.0624 (10)	0.0150 (7)	−0.0171 (7)	−0.0274 (8)
C1	0.0377 (9)	0.0282 (8)	0.0347 (9)	−0.0031 (8)	0.0006 (7)	−0.0051 (7)
C2	0.0418 (11)	0.0513 (12)	0.0465 (11)	0.0052 (10)	−0.0007 (9)	−0.0069 (9)
C3	0.0546 (14)	0.0668 (16)	0.0543 (13)	0.0054 (12)	0.0150 (11)	−0.0135 (11)
C4	0.0786 (17)	0.0638 (15)	0.0381 (11)	−0.0033 (13)	0.0048 (11)	−0.0094 (10)
C5	0.0679 (15)	0.0716 (16)	0.0422 (12)	0.0084 (13)	−0.0133 (11)	−0.0042 (11)
C6	0.0454 (12)	0.0560 (13)	0.0432 (11)	0.0093 (10)	−0.0039 (9)	−0.0065 (9)
N	0.0355 (9)	0.0404 (9)	0.0349 (8)	−0.0003 (7)	−0.0002 (7)	−0.0034 (7)

Geometric parameters (Å, º)

P1—O1	1.4919 (14)	C3—C4	1.372 (4)
P1—O2	1.4954 (15)	C3—H3	0.92 (3)
P1—O3	1.5538 (16)	C4—C5	1.373 (4)
P1—H1	1.29 (2)	C4—H4	0.95 (3)
O3—H8	0.82 (3)	C5—C6	1.382 (3)
C1—C2	1.370 (3)	C5—H5	0.99 (3)
C1—C6	1.371 (3)	C6—H6	0.93 (3)
C1—N	1.459 (2)	N—H7A	0.94 (3)
C2—C3	1.385 (3)	N—H7B	0.87 (3)
C2—H2	0.92 (2)	N—H7C	0.93 (3)
O1—P1—O2	115.70 (8)	C3—C4—C5	119.8 (2)
O1—P1—O3	107.40 (9)	C3—C4—H4	120.4 (16)
O2—P1—O3	111.75 (9)	C5—C4—H4	119.8 (16)
O1—P1—H1	109.0 (9)	C4—C5—C6	120.1 (2)
O2—P1—H1	107.7 (9)	C4—C5—H5	120.7 (17)
O3—P1—H1	104.6 (9)	C6—C5—H5	119.2 (17)
P1—O3—H8	112 (2)	C1—C6—C5	119.5 (2)
C2—C1—C6	121.09 (18)	C1—C6—H6	120.0 (15)
C2—C1—N	119.90 (17)	C5—C6—H6	120.5 (15)
C6—C1—N	118.99 (17)	C1—N—H7A	114.5 (14)
C1—C2—C3	118.9 (2)	C1—N—H7B	109.7 (16)
C1—C2—H2	118.2 (15)	H7A—N—H7B	113 (2)
C3—C2—H2	122.9 (15)	C1—N—H7C	110.7 (15)
C4—C3—C2	120.6 (2)	H7A—N—H7C	103 (2)
C4—C3—H3	121.5 (17)	H7B—N—H7C	106 (2)
C2—C3—H3	117.9 (17)
C6—C1—C2—C3	−0.4 (3)	C3—C4—C5—C6	−0.5 (4)
N—C1—C2—C3	−178.7 (2)	C2—C1—C6—C5	0.0 (3)
C1—C2—C3—C4	0.3 (4)	N—C1—C6—C5	178.3 (2)
C2—C3—C4—C5	0.1 (4)	C4—C5—C6—C1	0.5 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H8···O2^i	0.82 (3)	1.74 (3)	2.550 (2)	173 (3)
N—H7A···O2^ii	0.94 (3)	1.88 (3)	2.799 (2)	165 (2)
N—H7B···O1^iii	0.87 (3)	2.00 (3)	2.804 (2)	154 (2)
N—H7C···O1	0.93 (3)	1.77 (3)	2.693 (2)	174 (2)

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

(II) Anilinium hydrogenoxalate monohydrate

Crystal data

C6H8N^+·HC2O4^−·0.5H2O	F(000) = 808
Mr = 192.17	Dx = 1.418 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 23.9825 (19) Å	Cell parameters from 25 reflections
b = 5.7253 (14) Å	θ = 11.4–16.3°
c = 13.891 (2) Å	µ = 0.12 mm^−1
β = 109.340 (11)°	T = 293 K
V = 1799.7 (5) Å^3	Prism, white
Z = 8	0.49 × 0.48 × 0.29 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.005
Radiation source: fine-focus sealed tube	θmax = 27.5°, θmin = 3.0°
Graphite monochromator	h = 0→30
profile data from ω–2θ scans	k = 0→7
2189 measured reflections	l = −18→17
2062 independent reflections	3 standard reflections every 180 min
1735 reflections with I > 2σ(I)	intensity decay: 1.7%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	All H-atom parameters refined
wR(F^2) = 0.101	w = 1/[σ^2(Fo^2) + (0.0529P)^2 + 0.8427P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
2062 reflections	Δρmax = 0.31 e Å^−3
164 parameters	Δρmin = −0.16 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0211 (14)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.07951 (5)	0.24192 (19)	0.23798 (8)	0.0370 (3)
H1A	0.0555 (8)	0.109 (3)	0.2298 (13)	0.059 (5)*
H1B	0.0739 (7)	0.300 (3)	0.1764 (13)	0.049 (4)*
H1C	0.0685 (8)	0.346 (3)	0.2793 (14)	0.060 (5)*
C1	0.14192 (5)	0.1901 (2)	0.28895 (8)	0.0364 (3)
C2	0.15779 (7)	−0.0203 (3)	0.33765 (11)	0.0508 (4)
H2	0.1267 (9)	−0.138 (4)	0.3347 (14)	0.071 (5)*
C3	0.21687 (8)	−0.0640 (4)	0.38763 (13)	0.0672 (5)
H3	0.2272 (10)	−0.219 (4)	0.4185 (17)	0.084 (6)*
C4	0.25867 (8)	0.1007 (4)	0.38970 (13)	0.0691 (5)
H4	0.2986 (9)	0.073 (4)	0.4193 (15)	0.082 (6)*
C5	0.24243 (8)	0.3083 (4)	0.33934 (15)	0.0664 (5)
H5	0.2717 (10)	0.419 (4)	0.3392 (16)	0.082 (6)*
C6	0.18346 (7)	0.3548 (3)	0.28811 (12)	0.0513 (4)
H6	0.1705 (8)	0.497 (4)	0.2534 (14)	0.064 (5)*
O1	0.06771 (5)	0.68721 (14)	0.53305 (7)	0.0458 (3)
O2	0.05456 (5)	0.53471 (16)	0.38059 (6)	0.0467 (3)
O3	0.08251 (5)	0.25105 (17)	0.61327 (6)	0.0516 (3)
O4	0.06044 (5)	0.10789 (15)	0.45603 (7)	0.0491 (3)
H4A	0.0644 (9)	−0.024 (4)	0.4854 (17)	0.075 (6)*
C7	0.06364 (5)	0.52080 (18)	0.47337 (8)	0.0298 (2)
C8	0.07027 (5)	0.27599 (18)	0.52312 (8)	0.0298 (2)
O5	0.0000	0.8901 (2)	0.2500	0.0375 (3)
H5A	0.0159 (8)	0.793 (3)	0.3006 (13)	0.062 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0476 (6)	0.0319 (5)	0.0335 (5)	0.0014 (4)	0.0159 (4)	−0.0002 (4)
C1	0.0469 (6)	0.0353 (6)	0.0288 (5)	0.0029 (5)	0.0150 (5)	−0.0023 (4)
C2	0.0635 (9)	0.0417 (8)	0.0435 (7)	0.0034 (7)	0.0127 (6)	0.0062 (6)
C3	0.0753 (11)	0.0614 (10)	0.0525 (9)	0.0187 (9)	0.0046 (8)	0.0092 (8)
C4	0.0523 (9)	0.0878 (14)	0.0563 (9)	0.0158 (9)	0.0035 (7)	−0.0061 (9)
C5	0.0517 (9)	0.0755 (12)	0.0721 (11)	−0.0089 (9)	0.0209 (8)	−0.0064 (9)
C6	0.0546 (8)	0.0444 (8)	0.0575 (8)	−0.0014 (6)	0.0220 (7)	0.0041 (7)
O1	0.0810 (7)	0.0201 (4)	0.0366 (5)	0.0011 (4)	0.0200 (4)	−0.0021 (3)
O2	0.0838 (7)	0.0285 (4)	0.0316 (4)	0.0133 (4)	0.0243 (4)	0.0062 (3)
O3	0.0875 (7)	0.0334 (5)	0.0283 (5)	−0.0027 (5)	0.0117 (4)	0.0043 (3)
O4	0.0934 (8)	0.0192 (4)	0.0356 (5)	0.0014 (4)	0.0227 (5)	−0.0006 (3)
C7	0.0402 (6)	0.0202 (5)	0.0302 (5)	0.0031 (4)	0.0133 (4)	0.0018 (4)
C8	0.0394 (6)	0.0209 (5)	0.0291 (5)	0.0006 (4)	0.0114 (4)	0.0007 (4)
O5	0.0548 (7)	0.0255 (6)	0.0291 (6)	0.000	0.0099 (5)	0.000

Geometric parameters (Å, º)

N1—C1	1.4587 (16)	C4—H4	0.92 (2)
N1—H1A	0.939 (19)	C5—C6	1.382 (2)
N1—H1B	0.886 (17)	C5—H5	0.95 (2)
N1—H1C	0.926 (19)	C6—H6	0.94 (2)
C1—C2	1.3725 (19)	O1—C7	1.2453 (14)
C1—C6	1.375 (2)	O2—C7	1.2365 (14)
C2—C3	1.379 (2)	O3—C8	1.1963 (14)
C2—H2	1.00 (2)	O4—C8	1.3057 (14)
C3—C4	1.369 (3)	O4—H4A	0.85 (2)
C3—H3	0.98 (2)	C7—C8	1.5475 (15)
C4—C5	1.369 (3)	O5—H5A	0.877 (18)
C1—N1—H1A	112.4 (11)	C5—C4—H4	117.0 (15)
C1—N1—H1B	110.5 (10)	C3—C4—H4	122.5 (15)
H1A—N1—H1B	107.4 (15)	C4—C5—C6	119.99 (17)
C1—N1—H1C	106.7 (11)	C4—C5—H5	119.8 (14)
H1A—N1—H1C	108.2 (15)	C6—C5—H5	120.2 (14)
H1B—N1—H1C	111.7 (15)	C1—C6—C5	118.96 (16)
C2—C1—C6	121.53 (13)	C1—C6—H6	118.5 (11)
C2—C1—N1	119.35 (12)	C5—C6—H6	122.5 (11)
C6—C1—N1	119.11 (12)	C8—O4—H4A	110.4 (15)
C1—C2—C3	118.58 (16)	O2—C7—O1	126.34 (10)
C1—C2—H2	119.5 (12)	O2—C7—C8	118.71 (9)
C3—C2—H2	121.9 (12)	O1—C7—C8	114.95 (9)
C4—C3—C2	120.58 (17)	O3—C8—O4	125.65 (11)
C4—C3—H3	122.5 (13)	O3—C8—C7	121.93 (10)
C2—C3—H3	116.9 (13)	O4—C8—C7	112.41 (9)
C5—C4—C3	120.32 (16)
C6—C1—C2—C3	0.8 (2)	N1—C1—C6—C5	177.89 (13)
N1—C1—C2—C3	−178.38 (13)	C4—C5—C6—C1	0.1 (3)
C1—C2—C3—C4	0.9 (3)	O2—C7—C8—O3	175.55 (12)
C2—C3—C4—C5	−2.1 (3)	O1—C7—C8—O3	−5.00 (17)
C3—C4—C5—C6	1.5 (3)	O2—C7—C8—O4	−5.16 (15)
C2—C1—C6—C5	−1.3 (2)	O1—C7—C8—O4	174.29 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O5^i	0.939 (19)	1.915 (19)	2.8163 (15)	160.1 (16)
N1—H1B···O1^ii	0.886 (17)	1.949 (17)	2.7955 (15)	159.3 (15)
N1—H1C···O2	0.926 (19)	1.89 (2)	2.8067 (14)	171.2 (17)
O4—H4A···O1^i	0.85 (2)	1.77 (2)	2.6177 (14)	173 (2)
O5—H5A···O2	0.877 (18)	1.898 (19)	2.7516 (13)	163.8 (17)

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