4-Carbamoylpyridinium dihydrogen phosphate

The crystal structure of the title compound, C₆H₇N₂O⁺·H₂PO₄⁻, indicates that the anion is connected to the cation via an inter­molecular N—H...O hydrogen bond. There are other inter­molecular N—H...O and O—H...O hydrogen bonds as well as weak C—H...O hydrogen bonds in the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.024
• wR factor = 0.086
• Data-to-parameter ratio = 11.4

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT706_ALERT_1_A H...A   Calc     6.09(4), Rep     1.74(2), Dev..     108.75 Sigma
              H1   -O5      1.555   2.454
PLAT706_ALERT_1_A H...A   Calc     8.09(4), Rep     1.97(2), Dev..     153.00 Sigma
              H2A  -O6      1.555   4.454
PLAT706_ALERT_1_A H...A   Calc     6.88(4), Rep   1.830(10), Dev..     126.25 Sigma
              H3B  -O5      1.555   2.555
PLAT706_ALERT_1_A H...A   Calc     6.89(4), Rep   2.330(10), Dev..     114.00 Sigma
              H4A  -O6      1.555   1.455
PLAT707_ALERT_1_A D...A   Calc    6.626(4), Rep    2.643(6), Dev..     995.75 Sigma
              N1   -O5      1.555   2.454
PLAT707_ALERT_1_A D...A   Calc    8.744(5), Rep    2.928(8), Dev..    1163.20 Sigma
              N2   -O6      1.555   4.454
PLAT707_ALERT_1_A D...A   Calc    6.384(4), Rep    2.628(7), Dev..     939.00 Sigma
              O3   -O5      1.555   2.555
PLAT707_ALERT_1_A D...A   Calc    3.230(4), Rep    2.229(7), Dev..     250.25 Sigma
              C3   -O2      1.555   4.455
PLAT707_ALERT_1_A D...A   Calc    7.304(5), Rep    2.158(6), Dev..    1029.20 Sigma
              C4   -O6      1.555   1.455
PLAT708_ALERT_1_A D-H..A  Calc      122(3), Rep      169(2), Dev..      15.67 Sigma
              N1   -H1   -O5      1.555   1.555   2.454
PLAT708_ALERT_1_A D-H..A  Calc      130(3), Rep      177(2), Dev..      15.67 Sigma
              N2   -H2A  -O6      1.555   1.555   4.454
PLAT708_ALERT_1_A D-H..A  Calc       50(3), Rep      171(2), Dev..      40.33 Sigma
              O3   -H3B  -O5      1.555   1.555   2.555
PLAT708_ALERT_1_A D-H..A  Calc      115(3), Rep      159(2), Dev..      14.67 Sigma
              C4   -H4A  -O6      1.555   1.555   1.455

Alert level B
PLAT736_ALERT_1_B H...A   Calc     1.79(5), Rep   1.790(10) ......       5.00 su-Ra
              H4B  -O6      1.555   1.455

Alert level C
PLAT048_ALERT_1_C MoietyFormula Not Given ........................          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         P1
PLAT707_ALERT_1_C D...A   Calc    2.930(4), Rep    2.936(7), Dev..       1.50 Sigma
              N2   -O2      1.555   1.455
PLAT736_ALERT_1_C H...A   Calc     2.09(5), Rep     2.09(2) ......       2.50 su-Ra
              H2B  -O2      1.555   1.455
PLAT736_ALERT_1_C H...A   Calc     6.88(4), Rep   1.830(10) ......       4.00 su-Ra
              H3B  -O5      1.555   2.555
PLAT736_ALERT_1_C H...A   Calc     2.33(3), Rep   2.330(10) ......       3.00 su-Ra
              H3A  -O2      1.555   4.455
PLAT736_ALERT_1_C H...A   Calc     6.89(4), Rep   2.330(10) ......       4.00 su-Ra
              H4A  -O6      1.555   1.455
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C6 H7 N2 O
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              H2 O4 P

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.90
           From the CIF: _reflns_number_total               1858
           Count of symmetry unique reflns         1095
           Completeness (_total/calc)            169.68%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       763
           Fraction of Friedel pairs measured     0.697
           Are heavy atom types Z>Si present        yes
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2

  13 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
  10 ALERT level C = Check and explain
   4 ALERT level G = General alerts; check

  22 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

Research on phosphate compounds has attracted attention due to their applications as O-donor ligands in coordination chemistry (Szemes et al., 1996; Kortz et al., 2000; Pope et al., 2005; Chippindale, 2006; Oh et al., 2006). The crystal structures of two phosphate compounds (Chieh & Palenik, 1971; Okabe et al., 1993) a dichlorophosphate (Gholivand & Pourayoubi, 2004) and a dioxophosphate (Gholivand et al., 2005) have been reported. Recently, considerable attention has been paid to the subtle manipulation of hydrogen bonding in solid state structures (Steiner, 2002).

We have synthesized the title compound and report here its crystal structure. An ORTEP view of the molecular structure is presented in Fig. 1. The cation and anion are connected to each other via the intermolecular hydrogen bond N1—H1···O5.

In the anion, the bond lengths are P1—O3 1.571 (2), P1—O4 1.550 (2), P1—O5 1.508 (2) and P1—O6 1.498 (2) Å. These are in excellent agreement with the values found in the Cambridge Structural Database (Version of November, 2006; 313 hits; Allen, 2002): P—OH 1.550, P═O 1.504 and P—O^- 1.504 Å. The coordination geometry around the phosphorus atom is slightly distorted tetrahedral. The sum of the angles around the atoms N1 and N2 are 359.5° and 358°, respectively. These results show that the nitrogen atoms deviate slightly from planarity (i.e. from 360.0°).

The packing diagram of the title compound (Fig. 2) shows the four cations and anions in the unit cell. Each H₂PO₄^- anion is connected to other anions by intermolecular O3—H3B···O5 and O4—H4B···O6 hydrogen bonds, whereas the 4-pyridinium carboxylic acid amide cation is linked to another cation by the intermolecular N2—H2B···O2 hydrogen bond. All these hydrogen bonds, together with weak intermolecular C3—H3A···O2 and C4—-H4A···O6 hydrogen bonds produce a three dimensional polymeric chain in the crystal structure (Table 1).

Related literature

For related literature, see: Allen (2002); Chieh & Palenik (1971); Chippindale (2006); Gholivand & Pourayoubi (2004); Gholivand et al. (2005); Kortz (2000); Oh et al. (2006); Okabe et al. (1993); Pope et al. (2005); Steiner (2002); Szemes et al. (1996).

S2. Experimental

To a stirred suspension of phosphorus pentachloride (2.08 g, 10 mmol) in dry CCl₄ (35 ml), 4-pyridinecarboxylic acid amide (1.22 g, 10 mmol) was added at 298 K. The mixture was then heated at the reflux temperature (353–355 K) for 24 h. The mixture was cooled to room temperature and the reaction flask was placed in an ice bath. Formic acid (0.46 g, 10 mmol) was added dropwise to the mixture to release CO and HCl and finally to oxidize the phosphoramidate. After stirring for 24 h, a white precipitate was obtained, which was filtered and washed with H₂O (40 ml) and dried in air. The white precipitate (0.406 g, 2 mmol) was added to Hg₂Cl₂ (0.472 g,1 mmol) in hot ethanol (20 ml) to synthesize the Hg complex; however, catalytic hydrolysis of the phosphoramidate occurred. The product of this reaction was filtered and washed with ethanol (10 ml) and then recrystallized from distilled water at 298 K (yield 65%; m.p. 429–431 K).

S3. Refinement

All H atoms were located in a difference synthesis and refined isotropically [C—H = 0.88 (4) - 0.95 (4) Å, N—H = 0.87 (5) - 0.96 (4) Å, and O—H = 0.76 (5) - 0.81 (4) Å].

Computing details

Data collection: X-AREA (Stoe & Cie, 2005); cell refinement: X-AREA (Stoe & Cie, 2005); data reduction: X-AREA (Stoe & Cie, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. ORTEP view of the structure of the title compound, indicating the atom labeling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A packing diagram of the crystal structure, in which the hydrogen bonds are shown as dashed lines.

4-carbamoylpyridinium dihydrogen phosphate

Crystal data

C6H7N2O^+·H2PO4^−	F(000) = 456
Mr = 220.12	Dx = 1.601 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 4.7748 (7) Å	Cell parameters from 2500 reflections
b = 23.629 (7) Å	θ = 1.8–27.9°
c = 8.340 (3) Å	µ = 0.30 mm^−1
β = 103.94 (3)°	T = 293 K
V = 913.2 (5) Å^3	Block, colourless
Z = 4	0.35 × 0.25 × 0.06 mm

Data collection

STOE IPDS II diffractometer	1820 reflections with I > 2σ(I)
rotation method scans	Rint = 0.023
Absorption correction: numerical (shape of crystal determined optically)	θmax = 27.9°, θmin = 1.7°
Tmin = 0.910, Tmax = 0.980	h = −5→6
4586 measured reflections	k = −30→30
1858 independent reflections	l = −10→10

Refinement

Refinement on F^2	All H-atom parameters refined
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0273P)^2 + 0.979P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.024	(Δ/σ)max = 0.004
wR(F^2) = 0.086	Δρmax = 0.19 e Å^−3
S = 1.27	Δρmin = −0.26 e Å^−3
1858 reflections	Absolute structure: Flack (1983), 3363 Friedel pairs
163 parameters	Absolute structure parameter: 0.14 (11)
2 restraints

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.4437 (6)	0.24832 (11)	−0.4892 (4)	0.0339 (6)
C2	0.3191 (6)	0.19021 (10)	−0.4761 (3)	0.0278 (5)
C3	0.1908 (7)	0.17827 (11)	−0.3488 (4)	0.0345 (6)
H3A	0.177 (7)	0.2049 (13)	−0.269 (4)	0.027 (7)*
C4	0.0827 (7)	0.12493 (12)	−0.3384 (4)	0.0377 (6)
H4A	0.001 (8)	0.1135 (15)	−0.261 (5)	0.041 (9)*
C5	0.2227 (8)	0.09561 (12)	−0.5738 (4)	0.0423 (8)
H5	0.234 (9)	0.0650 (15)	−0.645 (5)	0.043 (9)*
C6	0.3409 (8)	0.14827 (13)	−0.5879 (4)	0.0393 (6)
H6	0.442 (10)	0.1551 (17)	−0.669 (5)	0.061 (12)*
N1	0.0962 (6)	0.08611 (10)	−0.4504 (3)	0.0359 (5)
H1	−0.003 (9)	0.0540 (19)	−0.437 (5)	0.062 (12)*
N2	0.2814 (6)	0.29148 (11)	−0.4720 (5)	0.0490 (8)
H2A	0.339 (9)	0.3298 (16)	−0.484 (5)	0.046 (9)*
H2B	0.099 (11)	0.2873 (19)	−0.475 (6)	0.067 (14)*
O2	0.6852 (6)	0.25244 (9)	−0.5158 (4)	0.0563 (8)
O3	−0.4720 (5)	−0.03277 (10)	−0.6565 (3)	0.0440 (5)
H3B	−0.377 (10)	−0.0199 (18)	−0.716 (5)	0.062 (13)*
O4	−0.5034 (5)	−0.08807 (9)	−0.4108 (3)	0.0374 (5)
H4B	−0.663 (11)	−0.0822 (18)	−0.444 (6)	0.059 (14)*
O5	−0.1924 (5)	−0.00130 (8)	−0.3746 (3)	0.0404 (5)
O6	−0.0475 (5)	−0.09051 (8)	−0.4977 (3)	0.0341 (4)
P1	−0.29004 (11)	−0.05229 (2)	−0.48238 (8)	0.02305 (15)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0295 (14)	0.0300 (13)	0.0434 (14)	−0.0039 (10)	0.0113 (11)	0.0071 (11)
C2	0.0255 (12)	0.0250 (11)	0.0342 (12)	−0.0009 (9)	0.0098 (11)	0.0037 (9)
C3	0.0448 (17)	0.0278 (12)	0.0346 (14)	−0.0012 (11)	0.0169 (13)	−0.0006 (10)
C4	0.0470 (18)	0.0334 (14)	0.0364 (14)	−0.0024 (12)	0.0170 (14)	0.0087 (11)
C5	0.060 (2)	0.0305 (14)	0.0369 (16)	−0.0009 (13)	0.0126 (16)	−0.0068 (11)
C6	0.0517 (19)	0.0347 (14)	0.0368 (15)	0.0016 (13)	0.0213 (14)	0.0007 (11)
N1	0.0416 (14)	0.0236 (10)	0.0401 (13)	−0.0055 (9)	0.0050 (11)	0.0049 (9)
N2	0.0386 (17)	0.0236 (10)	0.090 (2)	−0.0046 (8)	0.0256 (18)	0.0017 (12)
O2	0.0342 (12)	0.0442 (11)	0.097 (2)	−0.0012 (10)	0.0272 (15)	0.0221 (12)
O3	0.0345 (12)	0.0595 (13)	0.0350 (11)	−0.0087 (10)	0.0028 (9)	0.0145 (10)
O4	0.0218 (11)	0.0431 (11)	0.0477 (13)	−0.0055 (8)	0.0092 (9)	0.0164 (9)
O5	0.0518 (13)	0.0302 (9)	0.0441 (11)	−0.0118 (9)	0.0213 (10)	−0.0122 (8)
O6	0.0266 (10)	0.0308 (9)	0.0465 (12)	−0.0011 (7)	0.0116 (9)	−0.0015 (8)
P1	0.0231 (3)	0.0211 (2)	0.0264 (3)	−0.0036 (2)	0.0086 (2)	0.0005 (2)

Geometric parameters (Å, º)

C1—O2	1.230 (4)	C5—H5	0.95 (4)
C1—N2	1.310 (4)	C6—H6	0.93 (4)
C1—C2	1.511 (3)	N1—H1	0.92 (4)
C2—C3	1.376 (3)	N2—H2A	0.96 (4)
C2—C6	1.382 (4)	N2—H2B	0.87 (5)
C3—C4	1.373 (4)	O3—P1	1.571 (2)
C3—H3A	0.93 (3)	O3—H3B	0.81 (4)
C4—N1	1.322 (4)	O4—P1	1.550 (2)
C4—H4A	0.88 (4)	O4—H4B	0.76 (5)
C5—N1	1.332 (4)	O5—P1	1.5084 (19)
C5—C6	1.383 (4)	O6—P1	1.498 (2)
O2—C1—N2	124.3 (3)	C2—C6—H6	120 (3)
O2—C1—C2	119.2 (2)	C5—C6—H6	121 (3)
N2—C1—C2	116.5 (2)	C4—N1—C5	122.5 (3)
C3—C2—C6	119.6 (2)	C4—N1—H1	112 (3)
C3—C2—C1	119.9 (2)	C5—N1—H1	125 (3)
C6—C2—C1	120.5 (2)	C1—N2—H2A	122 (2)
C4—C3—C2	118.7 (2)	C1—N2—H2B	121 (3)
C4—C3—H3A	119.1 (18)	H2A—N2—H2B	115 (4)
C2—C3—H3A	122.1 (18)	P1—O3—H3B	114 (3)
N1—C4—C3	120.7 (3)	P1—O4—H4B	117 (3)
N1—C4—H4A	114 (2)	O6—P1—O5	113.46 (13)
C3—C4—H4A	125 (2)	O6—P1—O4	107.30 (11)
N1—C5—C6	119.2 (3)	O5—P1—O4	110.09 (13)
N1—C5—H5	118 (2)	O6—P1—O3	111.38 (13)
C6—C5—H5	123 (2)	O5—P1—O3	109.83 (14)
C2—C6—C5	119.3 (3)	O4—P1—O3	104.35 (13)
O2—C1—C2—C3	133.7 (3)	C2—C3—C4—N1	−1.4 (5)
N2—C1—C2—C3	−46.7 (4)	C3—C2—C6—C5	2.7 (5)
O2—C1—C2—C6	−44.2 (4)	C1—C2—C6—C5	−179.4 (3)
N2—C1—C2—C6	135.4 (3)	N1—C5—C6—C2	−1.5 (5)
C6—C2—C3—C4	−1.2 (4)	C3—C4—N1—C5	2.6 (5)
C1—C2—C3—C4	−179.2 (3)	C6—C5—N1—C4	−1.1 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O5^i	0.92 (4)	1.74 (2)	2.643 (6)	169 (2)
N2—H2A···O6^ii	0.96 (4)	1.97 (2)	2.928 (8)	177 (2)
N2—H2B···O2^iii	0.87 (5)	2.09 (2)	2.936 (7)	162 (2)
O3—H3B···O5^iv	0.81 (4)	1.83 (1)	2.628 (7)	171 (2)
O4—H4B···O6^iii	0.76 (5)	1.79 (1)	2.524 (8)	162 (2)
C3—H3A···O2^v	0.93 (3)	2.33 (1)	2.229 (7)	162 (2)
C4—H4A···O6^iii	0.88 (4)	2.33 (1)	2.158 (6)	159 (2)

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