2,6-Diamino-pyridinium dihydrogen phosphate.

In the crystal structure of the title compound, C(5)H(8)N(3) (+)·H(2)PO(4) (-), N-H⋯O hydrogen bonds, involving the unprotonated amino-group and the NH(+) group in the pyridinium ring and dihydrogenphosphate O atoms, link the cations and anions. A long chain-like stacking of dihydrogenphosphate anions along the c-axis direction is constructed by O-H⋯O hydrogen bonds. Also along the c-axis direction, π-π stacking between inversion-related pyridinium rings [centroid-centroid distance = 3.8051 (10) Å] forms columnar stacks of cations.

Related literature

For functional materials with similar crystal structures and their proton-transfer mechanism, see: Lasave et al. (2007 ▶); Morenzoni et al. (2007 ▶); Reiter (2002 ▶); Szklarz et al. (2011 ▶); Zhang et al. (2010 ▶). For the design of similar organic–inorganic functional materials, see: Horiuchi & Tokura (2008 ▶); Zhang & Xiong (2012 ▶).

Experimental

Crystal data

C5H8N3 +·H2O4P−

M = 207.13

Triclinic,

a = 7.4821 (4) Å

b = 8.1110 (2) Å

c = 8.1790 (1) Å

α = 70.811 (10)°

β = 74.980 (14)°

γ = 84.883 (15)°

V = 452.77 (3) Å3

Z = 2

Mo Kα radiation

μ = 0.29 mm−1

T = 153 K

0.50 × 0.30 × 0.20 mm

Data collection

Rigaku Mercury CCD diffractometer

Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T min = 0.868, T max = 0.944

5434 measured reflections

2057 independent reflections

1938 reflections with > σ(I)

R int = 0.013

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.090

S = 1.17

2057 reflections

133 parameters

4 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.30 e Å−3

Δρmin = −0.33 e Å−3

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812035489/pk2425sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812035489/pk2425Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812035489/pk2425Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C5H8N3+·H2O4P−	Z = 2
Mr = 207.13	F(000) = 216
Triclinic, P1	Dx = 1.519 Mg m−3
Hall symbol: -P 1	Melting point: 396 K
a = 7.4821 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.1110 (2) Å	Cell parameters from 1340 reflections
c = 8.1790 (1) Å	θ = 2.7–27.5°
α = 70.811 (10)°	µ = 0.29 mm−1
β = 74.980 (14)°	T = 153 K
γ = 84.883 (15)°	Block, yellow
V = 452.77 (3) Å3	0.50 × 0.30 × 0.20 mm

Rigaku Mercury CCD diffractometer	2057 independent reflections
Radiation source: fine-focus sealed tube	1938 reflections with > σ(I)
Graphite monochromator	Rint = 0.013
ω and φ scans	θmax = 27.5°, θmin = 2.7°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	h = −9→8
Tmin = 0.868, Tmax = 0.944	k = −10→10
5434 measured reflections	l = −10→10

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 1.17	w = 1/[σ2(Fo2) + (0.0388P)2 + 0.1286P] where P = (Fo2 + 2Fc2)/3
2057 reflections	(Δ/σ)max < 0.001
133 parameters	Δρmax = 0.30 e Å−3
4 restraints	Δρmin = −0.33 e Å−3

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.

	x	y	z	Uiso*/Ueq
N1	1.09610 (18)	−0.12682 (15)	0.27998 (16)	0.0371 (3)
H1	1.1789	−0.2047	0.3065	0.044*
N2	1.2828 (3)	0.0630 (2)	0.3140 (3)	0.0656 (5)
H1N2	1.294 (3)	0.166 (3)	0.304 (3)	0.079*
H2N2	1.350 (3)	−0.023 (3)	0.354 (3)	0.079*
N3	0.9398 (2)	−0.34142 (19)	0.2483 (2)	0.0494 (4)
H1N3	1.044 (3)	−0.400 (3)	0.241 (3)	0.059*
H2N3	0.852 (3)	−0.368 (3)	0.213 (3)	0.059*
C1	1.1233 (2)	0.0373 (2)	0.2779 (2)	0.0457 (4)
C2	0.9892 (3)	0.1617 (2)	0.2384 (3)	0.0615 (5)
H3C	1.0028	0.2753	0.2361	0.074*
C3	0.8346 (3)	0.1145 (2)	0.2023 (3)	0.0626 (5)
H4A	0.7440	0.1984	0.1763	0.075*
C4	0.8092 (2)	−0.0517 (2)	0.2035 (2)	0.0502 (4)
H5A	0.7037	−0.0804	0.1788	0.060*
C5	0.9458 (2)	−0.17538 (19)	0.2426 (2)	0.0376 (3)
P1	0.44212 (5)	−0.47555 (5)	0.25676 (5)	0.03232 (13)
O1	0.46973 (19)	−0.65793 (14)	0.39139 (15)	0.0485 (3)
H1A	0.5193	−0.6456	0.4650	0.073*
O2	0.39135 (16)	−0.34140 (14)	0.35200 (15)	0.0439 (3)
O3	0.63300 (16)	−0.4229 (2)	0.12119 (16)	0.0564 (4)
H3	0.6390	−0.4552	0.0348	0.085*
O4	0.30132 (14)	−0.50108 (16)	0.16548 (15)	0.0451 (3)

	U11	U22	U33	U12	U13	U23
N1	0.0417 (7)	0.0296 (6)	0.0424 (6)	−0.0011 (5)	−0.0130 (5)	−0.0124 (5)
N2	0.0784 (12)	0.0459 (9)	0.0813 (12)	−0.0211 (8)	−0.0222 (10)	−0.0242 (9)
N3	0.0382 (7)	0.0458 (8)	0.0771 (10)	0.0003 (6)	−0.0228 (7)	−0.0301 (7)
C1	0.0575 (10)	0.0331 (7)	0.0434 (8)	−0.0106 (6)	−0.0015 (7)	−0.0140 (6)
C2	0.0734 (13)	0.0313 (8)	0.0683 (12)	0.0015 (8)	0.0017 (10)	−0.0158 (8)
C3	0.0571 (11)	0.0464 (9)	0.0668 (12)	0.0172 (8)	−0.0012 (9)	−0.0102 (8)
C4	0.0384 (8)	0.0548 (10)	0.0524 (9)	0.0092 (7)	−0.0097 (7)	−0.0140 (8)
C5	0.0348 (7)	0.0401 (7)	0.0380 (7)	−0.0006 (6)	−0.0072 (6)	−0.0138 (6)
P1	0.0338 (2)	0.0371 (2)	0.0335 (2)	−0.00135 (14)	−0.01388 (14)	−0.01632 (15)
O1	0.0767 (8)	0.0343 (5)	0.0468 (6)	0.0030 (5)	−0.0286 (6)	−0.0196 (5)
O2	0.0588 (7)	0.0381 (5)	0.0482 (6)	0.0114 (5)	−0.0289 (5)	−0.0223 (5)
O3	0.0419 (6)	0.0955 (10)	0.0429 (6)	−0.0273 (6)	−0.0061 (5)	−0.0329 (7)
O4	0.0328 (5)	0.0688 (7)	0.0477 (6)	−0.0014 (5)	−0.0154 (5)	−0.0322 (6)

N1—C1	1.3586 (18)	C2—H3C	0.9300
N1—C5	1.3601 (19)	C3—C4	1.375 (3)
N1—H1	0.8600	C3—H4A	0.9300
N2—C1	1.350 (3)	C4—C5	1.389 (2)
N2—H1N2	0.822 (18)	C4—H5A	0.9300
N2—H2N2	0.848 (19)	P1—O4	1.5028 (10)
N3—C5	1.336 (2)	P1—O2	1.5050 (10)
N3—H1N3	0.874 (17)	P1—O3	1.5584 (12)
N3—H2N3	0.852 (17)	P1—O1	1.5608 (12)
C1—C2	1.379 (3)	O1—H1A	0.8200
C2—C3	1.378 (3)	O3—H3	0.8200
C1—N1—C5	123.93 (14)	C4—C3—H4A	118.7
C1—N1—H1	118.0	C2—C3—H4A	118.7
C5—N1—H1	118.0	C3—C4—C5	118.03 (17)
C1—N2—H1N2	110.8 (18)	C3—C4—H5A	121.0
C1—N2—H2N2	120.4 (18)	C5—C4—H5A	121.0
H1N2—N2—H2N2	128 (3)	N3—C5—N1	116.91 (13)
C5—N3—H1N3	117.6 (14)	N3—C5—C4	124.57 (15)
C5—N3—H2N3	116.4 (15)	N1—C5—C4	118.52 (14)
H1N3—N3—H2N3	120 (2)	O4—P1—O2	115.15 (6)
N2—C1—N1	115.83 (16)	O4—P1—O3	110.88 (6)
N2—C1—C2	126.02 (16)	O2—P1—O3	107.55 (7)
N1—C1—C2	118.14 (17)	O4—P1—O1	106.11 (7)
C3—C2—C1	118.83 (16)	O2—P1—O1	110.22 (6)
C3—C2—H3C	120.6	O3—P1—O1	106.64 (8)
C1—C2—H3C	120.6	P1—O1—H1A	109.5
C4—C3—C2	122.54 (17)	P1—O3—H3	109.5
C5—N1—C1—N2	−178.37 (15)	C2—C3—C4—C5	0.0 (3)
C5—N1—C1—C2	1.1 (2)	C1—N1—C5—N3	179.29 (15)
N2—C1—C2—C3	179.19 (19)	C1—N1—C5—C4	−1.4 (2)
N1—C1—C2—C3	−0.2 (3)	C3—C4—C5—N3	−179.93 (17)
C1—C2—C3—C4	−0.3 (3)	C3—C4—C5—N1	0.8 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2i	0.86	1.90	2.7515 (17)	170
N2—H2N2···O2i	0.85 (2)	2.58 (2)	3.241 (2)	136 (2)
N3—H1N3···O4i	0.87 (2)	2.05 (2)	2.9078 (19)	167 (2)
N2—H1N2···O1ii	0.82 (2)	2.40 (2)	3.0734 (19)	139 (2)
N2—H1N2···O4ii	0.82 (2)	2.56 (2)	3.342 (2)	159 (2)
O1—H1A···O2iii	0.82	1.76	2.5705 (15)	169
O3—H3···O4iv	0.82	1.73	2.5334 (15)	167
N3—H2N3···O3	0.85 (2)	2.11 (2)	2.9574 (18)	178 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2i	0.86	1.90	2.7515 (17)	170
N2—H2N2⋯O2i	0.85 (2)	2.58 (2)	3.241 (2)	136 (2)
N3—H1N3⋯O4i	0.87 (2)	2.05 (2)	2.9078 (19)	167 (2)
N2—H1N2⋯O1ii	0.82 (2)	2.40 (2)	3.0734 (19)	139 (2)
N2—H1N2⋯O4ii	0.82 (2)	2.56 (2)	3.342 (2)	159 (2)
O1—H1A⋯O2iii	0.82	1.76	2.5705 (15)	169
O3—H3⋯O4iv	0.82	1.73	2.5334 (15)	167
N3—H2N3⋯O3	0.85 (2)	2.11 (2)	2.9574 (18)	178 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .