Hydrogen bonding in cytosinium dihydrogen phosphite.

In the title compound, C(4)H(8)N(3)O(4)P(+)·H(2)PO(3) (-), the cytosine mol-ecule is monoprotonated and the phospho-ric acid is in the monoionized state. Strong hydrogen bonds, dominated by N-H⋯O inter-actions, are responsible for cohesion between the organic and inorganic layers and maintain the stability of this structure.

Related literature

For general background, see: Jeffrey & Saenger (1991 ▶); Kabanos et al. (1992 ▶); Weber & Craven (1990 ▶); Sivanesan et al. (2000 ▶). For hydrogen bonds, see: Blessing (1986 ▶); Masse & Levy (1991 ▶). For related structures, see: Bendheif et al. (2003 ▶); Bouchouit et al. (2005 ▶); Benali-Cherif, Abouimrane et al. (2002 ▶); Benali-Cherif et al. (2007 ▶); Benali-Cherif, Benguedouar et al. (2002 ▶); Bendjeddou et al. (2003 ▶); Cherouana, Benali-Cherif & Bendjeddou (2003 ▶); Cherouana, Bouchouit et al. (2003 ▶); Messai et al. (2009 ▶).

Experimental

Crystal data

C4H6N3O+·H2PO3 −

M = 193.10

Triclinic,

a = 4.5625 (3) Å

b = 6.4739 (4) Å

c = 6.5933 (6) Å

α = 92.934 (4)°

β = 91.236 (4)°

γ = 98.627 (5)°

V = 192.21 (2) Å3

Z = 1

Mo Kα radiation

μ = 0.34 mm−1

T = 293 K

0.1 × 0.1 × 0.1 mm

Data collection

Nonius KappaCCD diffractometer

Absorption correction: none

1500 measured reflections

1500 independent reflections

1430 reflections with I > 2σ(I)

Refinement

R[F 2 > 2σ(F 2)] = 0.035

wR(F 2) = 0.084

S = 1.13

1500 reflections

112 parameters

4 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.33 e Å−3

Absolute structure: Flack (1983 ▶), 580 with Friedel pairs

Flack parameter: 0.06 (10)

Data collection: COLLECT (Nonius, 1997–2000 ▶); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO (Otwinowski & Minor, 1997 ▶) and SCALEPACK; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809014020/gw2061sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809014020/gw2061Isup2.hkl

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

C4H6N3O+·H2PO3−	Z = 1
Mr = 193.10	F(000) = 100
Triclinic, P1	Dx = 1.668 Mg m−3
Hall symbol: P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.5625 (3) Å	Cell parameters from 739 reflections
b = 6.4739 (4) Å	θ = 0.7–27.9°
c = 6.5933 (6) Å	µ = 0.34 mm−1
α = 92.934 (4)°	T = 293 K
β = 91.236 (4)°	Cubic, yellow
γ = 98.627 (5)°	0.1 × 0.1 × 0.1 mm
V = 192.21 (2) Å3

Nonius KappaCCD diffractometer	1430 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.0000
horizonally mounted graphite crystal	θmax = 28.0°, θmin = 3.2°
Detector resolution: 9 pixels mm-1	h = −6→5
CCD rotation images, thick slices scans	k = −8→8
1500 measured reflections	l = −8→8
1500 independent reflections

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.084	w = 1/[σ2(Fo2) + (0.0447P)2 + 0.0402P] where P = (Fo2 + 2Fc2)/3
S = 1.13	(Δ/σ)max < 0.001
1500 reflections	Δρmax = 0.25 e Å−3
112 parameters	Δρmin = −0.33 e Å−3
4 restraints	Absolute structure: Flack (1983), with how many Friedel pairs?
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.06 (10)

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
O7	0.3049 (5)	0.5610 (3)	1.0498 (3)	0.0265 (5)
N1	0.3442 (5)	0.6856 (3)	0.7331 (4)	0.0213 (5)
H1	0.2420	0.7833	0.7642	0.026*
N3	0.5864 (5)	0.4107 (3)	0.8218 (3)	0.0183 (5)
H3	0.6371	0.3301	0.9118	0.022*
N8	0.8625 (5)	0.2462 (4)	0.5932 (4)	0.0236 (5)
H7	0.9227	0.1652	0.6793	0.028*
H8	0.9180	0.2312	0.4701	0.028*
C2	0.4021 (5)	0.5545 (4)	0.8791 (4)	0.0177 (5)
C4	0.6911 (5)	0.3898 (4)	0.6323 (4)	0.0178 (5)
C5	0.6099 (6)	0.5224 (4)	0.4837 (4)	0.0232 (6)
H5	0.6711	0.5094	0.3507	0.028*
C6	0.4412 (6)	0.6684 (4)	0.5406 (4)	0.0228 (6)
H6	0.3901	0.7593	0.4457	0.027*
P1	−0.06174 (7)	0.00189 (6)	0.08872 (6)	0.01852 (18)
O1	0.1928 (4)	0.0549 (3)	0.2547 (3)	0.0209 (4)
H1A	0.3538	0.0628	0.2004	0.031*
O2	0.0527 (4)	−0.0044 (3)	−0.1225 (3)	0.0222 (4)
O3	−0.2857 (4)	0.1487 (3)	0.1256 (3)	0.0214 (4)
H9	−0.172 (6)	−0.1857 (19)	0.137 (5)	0.026*

	U11	U22	U33	U12	U13	U23
O7	0.0323 (11)	0.0300 (11)	0.0203 (11)	0.0138 (8)	0.0056 (9)	0.0032 (8)
N1	0.0274 (12)	0.0176 (11)	0.0212 (13)	0.0108 (9)	−0.0016 (10)	0.0023 (9)
N3	0.0231 (11)	0.0198 (11)	0.0138 (11)	0.0079 (9)	−0.0004 (9)	0.0043 (8)
N8	0.0343 (13)	0.0234 (11)	0.0163 (11)	0.0134 (9)	0.0058 (10)	0.0031 (9)
C2	0.0175 (13)	0.0174 (13)	0.0181 (15)	0.0036 (10)	−0.0010 (10)	−0.0007 (10)
C4	0.0218 (13)	0.0166 (12)	0.0150 (13)	0.0034 (10)	−0.0016 (11)	−0.0005 (10)
C5	0.0327 (14)	0.0224 (13)	0.0165 (13)	0.0094 (11)	0.0002 (12)	0.0042 (10)
C6	0.0308 (15)	0.0188 (13)	0.0193 (15)	0.0056 (11)	−0.0032 (11)	0.0033 (10)
P1	0.0176 (3)	0.0189 (3)	0.0200 (4)	0.0051 (2)	0.0016 (2)	0.0033 (2)
O1	0.0142 (8)	0.0330 (10)	0.0170 (10)	0.0066 (7)	0.0028 (7)	0.0039 (7)
O2	0.0271 (10)	0.0250 (10)	0.0174 (10)	0.0129 (8)	0.0018 (8)	0.0008 (8)
O3	0.0175 (9)	0.0255 (10)	0.0235 (11)	0.0098 (7)	0.0024 (8)	0.0032 (8)

O7—C2	1.220 (3)	C4—C5	1.414 (4)
N1—C6	1.358 (4)	C5—C6	1.349 (4)
N1—C2	1.362 (4)	C5—H5	0.9300
N1—H1	0.8600	C6—H6	0.9300
N3—C4	1.354 (3)	P1—O2	1.498 (2)
N3—C2	1.389 (3)	P1—O3	1.5114 (18)
N3—H3	0.8600	P1—O1	1.5655 (18)
N8—C4	1.321 (3)	P1—H9	1.301 (16)
N8—H7	0.8601	O1—H1A	0.8200
N8—H8	0.8600
C6—N1—C2	122.8 (2)	N3—C4—C5	118.4 (2)
C6—N1—H1	118.6	C6—C5—C4	118.1 (3)
C2—N1—H1	118.6	C6—C5—H5	121.0
C4—N3—C2	123.8 (2)	C4—C5—H5	121.0
C4—N3—H3	118.1	C5—C6—N1	121.5 (2)
C2—N3—H3	118.1	C5—C6—H6	119.2
C4—N8—H7	126.0	N1—C6—H6	119.2
C4—N8—H8	117.2	O2—P1—O3	114.99 (10)
H7—N8—H8	116.8	O2—P1—O1	112.60 (10)
O7—C2—N1	123.7 (2)	O3—P1—O1	108.41 (11)
O7—C2—N3	121.1 (2)	O2—P1—H9	110.0 (14)
N1—C2—N3	115.2 (2)	O3—P1—H9	109.9 (13)
N8—C4—N3	119.0 (2)	O1—P1—H9	99.9 (14)
N8—C4—C5	122.7 (3)	P1—O1—H1A	109.5
C6—N1—C2—O7	−176.3 (2)	C2—N3—C4—C5	0.3 (4)
C6—N1—C2—N3	4.5 (3)	N8—C4—C5—C6	−178.0 (3)
C4—N3—C2—O7	177.1 (2)	N3—C4—C5—C6	2.4 (4)
C4—N3—C2—N1	−3.7 (3)	C4—C5—C6—N1	−1.7 (4)
C2—N3—C4—N8	−179.2 (2)	C2—N1—C6—C5	−2.0 (4)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2i	0.86	1.86	2.713 (3)	170
O1—H1A···O3ii	0.82	1.75	2.542 (3)	163
N3—H3···O3iii	0.86	1.94	2.797 (3)	175
N8—H7···O2iii	0.86	1.89	2.750 (3)	178
N8—H8···O1ii	0.86	2.29	3.034 (3)	145
N8—H8···O3ii	0.86	2.44	3.153 (3)	141

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2i	0.86	1.86	2.713 (3)	170
O1—H1A⋯O3ii	0.82	1.75	2.542 (3)	163
N3—H3⋯O3iii	0.86	1.94	2.797 (3)	175
N8—H7⋯O2iii	0.86	1.89	2.750 (3)	178
N8—H8⋯O1ii	0.86	2.29	3.034 (3)	145
N8—H8⋯O3ii	0.86	2.44	3.153 (3)	141

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