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The crystal structure of ammonium 2-mercapto­pyridine-3-carboxyl­ate hydrate, NH4+·C6H4NO2S-·H2O, contains a zwitterionic anion with the pyridine-N atom protonated. All potential donor and acceptor atoms are involved in hydrogen-bonding, resulting in a three-dimensional network structure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803006020/tk6097sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803006020/tk6097Isup2.hkl
Contains datablock I

CCDC reference: 209979

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.004 Å
  • R factor = 0.040
  • wR factor = 0.174
  • Data-to-parameter ratio = 17.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_353 Alert C Long N-H Bond (0.87A) N(11) - H(12) = 1.01 Ang.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

2-Mercapto-substituted alcohols and acids have considerable utility as bidentate ligands in coordination chemistry (Harris & Livingstone, 1964; McAuliffe, 1986). These ligands may act as either mono- or di-anionic species and with bismuth(III) often give octahedral complexes (Agoes et al., 1997; Sagatys et al., 2003). The ammonium tris(2-mercaptobenzoato-O,S)bismuth(III) dihydrate complex (Sagatys et al., 2003) is readily formed, while the complex with the analogous ligand thionicotinic acid (2-mercaptopyridine-3-carboxylic acid) is less so. The structure of the ionic species formed from the latter acid under aqueous ammoniacal conditions was therefore determined in an attempt to explain this anomoly.

The crystal structure of ammonium 2-mercaptopyridine-3-carboxylate hydrate, (I), confirms the presence of a zwitterionic anion species with protonation at the pyridine-N atom and deprotonation as the carboxylate and thiolate residues (Fig. 1). The plane of the carboxylate group at C3 is anticlinally related to that of the pyridine ring [torsion angle C2—C3—C7—O71 = 75.1 (4)°]. The formation of the stable zwitterion probably accounts for the different behaviour of thionicotinic acid compared to thiosalicylic acid as a complexing agent.

The crystal packing of (I) shows that all ammonium H atoms, together with the zwitterionic pyridinium H atom, are involved in hydrogen-bonding interactions to carboxylate and water O atoms, as well as to a thiol-S atom [N11—H14···S2 = 3.350 (3) Å] (Fig. 2 and Table 1). The water molecule is also hydrogen bonded to two carboxylate O atoms, giving a three-dimensional network structure.

Experimental top

The title compound, (I), was prepared by dissolving 5.0 g (3.2 mmol) of thionicotinic acid (2-mercaptopyridine-3-carboxylic acid) in 150 ml of 28% ammonia solution at room temperature and allowing the filtered solution to evaporate to dryness at room temperature over a period of ca 3 weeks.

Refinement top

H atoms involved in hydrogen-bonding interactions (i.e. H1, H11, H12, H13, H14, H21 and H22) were located by difference methods, and both positional and displacement parameters were refined. Other H atoms were included in the riding-model approximation.

Computing details top

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON for Windows (Spek, 1999).

Figures top
[Figure 1] Fig. 1. The molecular configuration and atom-naming scheme for (I). Ellipsoids are shown at the 30% probability level.
[Figure 2] Fig. 2. The packing of (I) in the unit cell, viewed down a, showing hydrogen-bonding interactions as broken lines.
ammonium 2-mercaptopyridine-3-carboxylate hydrate top
Crystal data top
H4N+·C6H4NO2S·H2OF(000) = 400
Mr = 190.22Dx = 1.424 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ynCell parameters from 25 reflections
a = 6.8327 (4) Åθ = 11.8–18.9°
b = 10.8017 (12) ŵ = 0.34 mm1
c = 12.2436 (5) ÅT = 296 K
β = 100.854 (5)°Plate, colourless
V = 887.47 (12) Å30.35 × 0.35 × 0.12 mm
Z = 4
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.041
Radiation source: Rigaku rotating anodeθmax = 29.5°, θmin = 2.5°
Graphite monochromatorh = 08
ω–2θ scansk = 013
2631 measured reflectionsl = 1515
2451 independent reflections3 standard reflections every 150 reflections
1113 reflections with I > 2σ(I) intensity decay: 0.5%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.040H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.174 w = 1/[σ2(Fo2) + (0.1032P)2 + 0.154P]
where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max < 0.001
2451 reflectionsΔρmax = 0.33 e Å3
138 parametersΔρmin = 0.24 e Å3
Primary atom site location: structure-invariant direct methods
Crystal data top
H4N+·C6H4NO2S·H2OV = 887.47 (12) Å3
Mr = 190.22Z = 4
Monoclinic, P21/nMo Kα radiation
a = 6.8327 (4) ŵ = 0.34 mm1
b = 10.8017 (12) ÅT = 296 K
c = 12.2436 (5) Å0.35 × 0.35 × 0.12 mm
β = 100.854 (5)°
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.041
2631 measured reflections3 standard reflections every 150 reflections
2451 independent reflections intensity decay: 0.5%
1113 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.040138 parameters
wR(F2) = 0.174H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.33 e Å3
2451 reflectionsΔρmin = 0.24 e Å3
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
xyzUiso*/Ueq
S20.16986 (13)0.37274 (8)0.37160 (7)0.0356 (3)
O710.2178 (3)0.1737 (2)0.16045 (17)0.0381 (8)
O720.0904 (3)0.1222 (2)0.17581 (17)0.0369 (7)
N10.2715 (4)0.1932 (3)0.5196 (2)0.0340 (9)
C20.2008 (4)0.2221 (3)0.4105 (2)0.0274 (9)
C30.1579 (4)0.1187 (3)0.3383 (2)0.0261 (9)
C40.1793 (5)0.0004 (3)0.3796 (3)0.0357 (10)
C50.2488 (5)0.0213 (3)0.4930 (3)0.0393 (11)
C60.2945 (5)0.0767 (4)0.5616 (3)0.0409 (11)
C70.0906 (5)0.1411 (3)0.2149 (2)0.0270 (9)
N110.2151 (4)0.1086 (3)0.0645 (2)0.0386 (9)
O20.6010 (4)0.2069 (3)0.2788 (2)0.0601 (10)
H10.316 (5)0.261 (4)0.570 (3)0.047 (11)*
H40.1508000.0684000.3314000.0430*
H50.2648000.1012000.5227000.0480*
H60.3444000.0689000.6380000.0500*
H110.147 (8)0.034 (6)0.092 (5)0.080 (16)*
H120.194 (7)0.127 (6)0.013 (5)0.079 (15)*
H130.136 (7)0.157 (5)0.116 (4)0.069 (15)*
H140.346 (6)0.116 (5)0.067 (5)0.075 (14)*
H210.475 (6)0.189 (6)0.237 (6)0.066 (15)*
H220.702 (7)0.179 (6)0.258 (6)0.070 (15)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S20.0459 (5)0.0313 (4)0.0300 (4)0.0004 (4)0.0079 (3)0.0025 (4)
O710.0400 (14)0.0517 (15)0.0239 (11)0.0036 (12)0.0097 (9)0.0009 (10)
O720.0325 (13)0.0464 (14)0.0281 (11)0.0001 (11)0.0039 (9)0.0002 (11)
N10.0356 (16)0.0439 (17)0.0207 (12)0.0019 (14)0.0005 (11)0.0052 (12)
C20.0242 (16)0.0354 (18)0.0222 (14)0.0004 (13)0.0030 (11)0.0007 (12)
C30.0250 (15)0.0323 (17)0.0208 (12)0.0005 (13)0.0037 (10)0.0012 (12)
C40.042 (2)0.0314 (17)0.0335 (17)0.0011 (15)0.0066 (14)0.0007 (14)
C50.048 (2)0.037 (2)0.0326 (17)0.0069 (16)0.0070 (14)0.0131 (14)
C60.044 (2)0.054 (2)0.0229 (15)0.0070 (18)0.0016 (14)0.0103 (16)
C70.0322 (17)0.0257 (15)0.0218 (13)0.0039 (13)0.0021 (11)0.0022 (12)
N110.0437 (17)0.0412 (18)0.0298 (14)0.0062 (14)0.0040 (12)0.0003 (12)
O20.0365 (15)0.091 (2)0.0523 (17)0.0042 (15)0.0074 (12)0.0295 (16)
Geometric parameters (Å, º) top
S2—C21.697 (3)N11—H121.01 (6)
O71—C71.242 (4)N11—H140.90 (4)
O72—C71.256 (4)C2—C31.420 (4)
O2—H210.94 (5)C3—C41.380 (5)
O2—H220.84 (5)C3—C71.514 (3)
N1—C61.357 (5)C4—C51.399 (5)
N1—C21.368 (3)C5—C61.351 (5)
N1—H10.97 (4)C4—H40.9394
N11—H130.91 (5)C5—H50.9349
N11—H110.96 (6)C6—H60.9371
H21—O2—H22119 (6)C2—C3—C4120.7 (3)
C2—N1—C6125.2 (3)C4—C3—C7120.4 (3)
C6—N1—H1117 (2)C3—C4—C5120.5 (3)
C2—N1—H1117 (2)C4—C5—C6119.1 (3)
H11—N11—H14119 (5)N1—C6—C5119.6 (3)
H12—N11—H13112 (5)O71—C7—C3118.0 (3)
H12—N11—H14109 (5)O72—C7—C3116.5 (3)
H13—N11—H14113 (5)O71—C7—O72125.5 (2)
H11—N11—H1393 (5)C3—C4—H4120.24
H11—N11—H12111 (5)C5—C4—H4119.27
S2—C2—C3125.4 (2)C4—C5—H5121.88
S2—C2—N1119.7 (2)C6—C5—H5119.02
N1—C2—C3114.9 (3)N1—C6—H6117.12
C2—C3—C7118.9 (3)C5—C6—H6123.25
C6—N1—C2—S2177.0 (3)C2—C3—C7—O7175.1 (4)
C6—N1—C2—C32.6 (4)C2—C3—C7—O72106.5 (3)
C2—N1—C6—C51.1 (5)C7—C3—C4—C5177.5 (3)
N1—C2—C3—C42.9 (4)C4—C3—C7—O7274.3 (4)
N1—C2—C3—C7176.4 (3)C4—C3—C7—O71104.2 (4)
S2—C2—C3—C4176.8 (2)C3—C4—C5—C60.1 (5)
S2—C2—C3—C74.0 (4)C4—C5—C6—N10.3 (6)
C2—C3—C4—C51.7 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O72i0.97 (4)1.83 (4)2.801 (4)174 (4)
N11—H11···O72ii0.96 (6)1.97 (6)2.892 (4)159 (5)
N11—H12···O711.01 (6)1.85 (6)2.839 (3)166 (4)
N11—H13···O2iii0.91 (5)1.94 (5)2.774 (4)151 (4)
N11—H14···S2iv0.90 (4)2.47 (4)3.350 (3)164 (5)
O2—H21···O710.94 (5)1.84 (5)2.767 (3)173 (6)
O2—H22···O72v0.84 (5)1.98 (6)2.806 (3)167 (7)
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x, y, z; (iii) x1/2, y+1/2, z1/2; (iv) x+1/2, y+1/2, z1/2; (v) x+1, y, z.

Experimental details

Crystal data
Chemical formulaH4N+·C6H4NO2S·H2O
Mr190.22
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)6.8327 (4), 10.8017 (12), 12.2436 (5)
β (°) 100.854 (5)
V3)887.47 (12)
Z4
Radiation typeMo Kα
µ (mm1)0.34
Crystal size (mm)0.35 × 0.35 × 0.12
Data collection
DiffractometerRigaku AFC-7R
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2631, 2451, 1113
Rint0.041
(sin θ/λ)max1)0.693
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.174, 1.00
No. of reflections2451
No. of parameters138
No. of restraints?
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.33, 0.24

Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999), MSC/AFC Diffractometer Control Software, TEXSAN for Windows (Molecular Structure Corporation, 1999), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON for Windows (Spek, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O72i0.97 (4)1.83 (4)2.801 (4)174 (4)
N11—H11···O72ii0.96 (6)1.97 (6)2.892 (4)159 (5)
N11—H12···O711.01 (6)1.85 (6)2.839 (3)166 (4)
N11—H13···O2iii0.91 (5)1.94 (5)2.774 (4)151 (4)
N11—H14···S2iv0.90 (4)2.47 (4)3.350 (3)164 (5)
O2—H21···O710.94 (5)1.84 (5)2.767 (3)173 (6)
O2—H22···O72v0.84 (5)1.98 (6)2.806 (3)167 (7)
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x, y, z; (iii) x1/2, y+1/2, z1/2; (iv) x+1/2, y+1/2, z1/2; (v) x+1, y, z.
 

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