organic compounds
2-(Pyridin-2-ylamino)pyridinium thiocyanate acetonitrile monosolvate
aNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth 6031, South Africa
*Correspondence e-mail: richard.betz@webmail.co.za
The title compound, C10H10N3+·NCS−·CH3CN, is the acetonitrile solvate of the thiocyanate salt of protonated dipyridin-2-ylamine. Protonation occurs at one of the pyridine N atoms. The molecular geometry around the central N atom is essentially planar (sum of angles = 359.89°). In the crystal, N—H⋯N hydrogen bonds, as well as C—H⋯S contacts link the different residues into chains along the c-axis direction. Interaction between aromatic systems gives rise to π-stacking, the shortest distance between two π-systems being 3.6902 (6) Å. Both the protonated and the non-protonated pyridyl groups are involved in the latter interaction.
Related literature
For the ); Pyrka & Pinkerton (1992); Schödel et al. (1996). For the crystal structures of comparable chloride, bromide and nitrate salts, see: Bock et al. (1998); Junk et al. (2006); Du & Zhao (2004). For the use of chelating ligands in coordination chemistry, see: Gade (1998). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995).
of dipyridin-2-ylamine, see for example: Johnson & Jacobson (1973Experimental
Crystal data
|
Refinement
|
Data collection: APEX2 (Bruker, 2010); cell SAINT (Bruker, 2010); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536811026808/ya2142sup1.cif
contains datablocks I, global. DOI:Supporting information file. DOI: 10.1107/S1600536811026808/ya2142Isup2.cdx
Structure factors: contains datablock I. DOI: 10.1107/S1600536811026808/ya2142Isup3.hkl
Supporting information file. DOI: 10.1107/S1600536811026808/ya2142Isup4.cml
The compound was prepared upon reacting of 4-bromobenzyl chloride (2.5 mmol) with potassium thiocyanate (2.5 mmol) and dipyridin-2-ylamine (2.5 mmol) in refluxing acetonitrile (15 mL) under nitrogen for two hours. Crystals suitable for the X-ray diffraction study were obtained upon free evaporation of the reaction mixture.
Carbon-bound H atoms were placed in calculated positions (C-H 0.95 Å, for methyl H atoms 0.98 Å) and were included in the
in the riding model approximation, with U(H) set to 1.2Ueq(C) [1.5Ueq(C) for methyl H atoms]. Both nitrogen-bound H atoms were located in a difference Fourier map and refined isotropically, N(pyr)-H 0.926 (15) Å; N(amine)-H 0.903 (15) Å.Data collection: APEX2 (Bruker, 2010); cell
SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).C10H10N3+·CNS−·C2H3N | Z = 2 |
Mr = 271.34 | F(000) = 284 |
Triclinic, P1 | Dx = 1.349 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71069 Å |
a = 7.5450 (3) Å | Cell parameters from 9959 reflections |
b = 7.8790 (3) Å | θ = 2.7–28.3° |
c = 11.9900 (4) Å | µ = 0.24 mm−1 |
α = 76.849 (1)° | T = 100 K |
β = 75.211 (1)° | Block, colourless |
γ = 81.371 (1)° | 0.54 × 0.40 × 0.34 mm |
V = 667.88 (4) Å3 |
Bruker APEXII CCD diffractometer | 3313 independent reflections |
Radiation source: fine-focus sealed tube | 3113 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.016 |
ϕ and ω scans | θmax = 28.3°, θmin = 2.7° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −10→10 |
Tmin = 0.899, Tmax = 1.000 | k = −10→10 |
11528 measured reflections | l = −15→15 |
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)] = 0.028 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.082 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0442P)2 + 0.184P] where P = (Fo2 + 2Fc2)/3 |
3313 reflections | (Δ/σ)max < 0.001 |
181 parameters | Δρmax = 0.43 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C10H10N3+·CNS−·C2H3N | γ = 81.371 (1)° |
Mr = 271.34 | V = 667.88 (4) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.5450 (3) Å | Mo Kα radiation |
b = 7.8790 (3) Å | µ = 0.24 mm−1 |
c = 11.9900 (4) Å | T = 100 K |
α = 76.849 (1)° | 0.54 × 0.40 × 0.34 mm |
β = 75.211 (1)° |
Bruker APEXII CCD diffractometer | 3313 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 3113 reflections with I > 2σ(I) |
Tmin = 0.899, Tmax = 1.000 | Rint = 0.016 |
11528 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | 0 restraints |
wR(F2) = 0.082 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | Δρmax = 0.43 e Å−3 |
3313 reflections | Δρmin = −0.20 e Å−3 |
181 parameters |
x | y | z | Uiso*/Ueq | ||
S1 | 0.29241 (3) | 0.79739 (3) | 0.47166 (2) | 0.02280 (9) | |
N1 | 0.25212 (11) | 0.56147 (10) | 0.07444 (7) | 0.01647 (16) | |
H71 | 0.265 (2) | 0.6054 (19) | 0.1350 (13) | 0.031 (3)* | |
N2 | 0.17025 (10) | 0.32447 (10) | 0.01896 (7) | 0.01588 (16) | |
N3 | 0.31181 (10) | 0.59208 (10) | −0.13124 (7) | 0.01503 (15) | |
H73 | 0.267 (2) | 0.484 (2) | −0.1156 (13) | 0.034 (4)* | |
N10 | 0.30552 (13) | 0.68937 (12) | 0.26202 (8) | 0.02613 (19) | |
N20 | 0.20385 (13) | 0.32594 (13) | 0.74643 (8) | 0.0283 (2) | |
C1 | 0.30149 (12) | 0.73414 (12) | 0.34893 (8) | 0.01752 (18) | |
C2 | 0.20307 (13) | 0.31158 (12) | 0.65393 (9) | 0.02028 (19) | |
C3 | 0.19939 (15) | 0.29362 (15) | 0.53641 (9) | 0.0254 (2) | |
H31 | 0.0713 | 0.3014 | 0.5301 | 0.038* | |
H32 | 0.2624 | 0.1799 | 0.5219 | 0.038* | |
H33 | 0.2620 | 0.3875 | 0.4781 | 0.038* | |
C11 | 0.18123 (12) | 0.39962 (11) | 0.10570 (8) | 0.01469 (17) | |
C12 | 0.12748 (12) | 0.32258 (12) | 0.22524 (8) | 0.01750 (18) | |
H12 | 0.1330 | 0.3817 | 0.2849 | 0.021* | |
C13 | 0.06646 (13) | 0.15854 (13) | 0.25345 (8) | 0.01970 (19) | |
H13 | 0.0315 | 0.1012 | 0.3334 | 0.024* | |
C14 | 0.05640 (13) | 0.07707 (12) | 0.16347 (9) | 0.01948 (18) | |
H14 | 0.0156 | −0.0364 | 0.1809 | 0.023* | |
C15 | 0.10734 (12) | 0.16579 (12) | 0.04863 (8) | 0.01750 (18) | |
H15 | 0.0974 | 0.1119 | −0.0125 | 0.021* | |
C21 | 0.31450 (11) | 0.65375 (11) | −0.03559 (8) | 0.01480 (17) | |
C22 | 0.38354 (12) | 0.81677 (12) | −0.05213 (8) | 0.01729 (18) | |
H22 | 0.3894 | 0.8618 | 0.0138 | 0.021* | |
C23 | 0.44192 (12) | 0.90943 (12) | −0.16401 (9) | 0.01963 (19) | |
H23 | 0.4863 | 1.0203 | −0.1757 | 0.024* | |
C24 | 0.43654 (13) | 0.84134 (12) | −0.26181 (8) | 0.01979 (19) | |
H24 | 0.4770 | 0.9051 | −0.3396 | 0.024* | |
C25 | 0.37210 (12) | 0.68195 (12) | −0.24274 (8) | 0.01763 (18) | |
H25 | 0.3693 | 0.6334 | −0.3078 | 0.021* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.02876 (14) | 0.02784 (14) | 0.01436 (12) | −0.00606 (10) | −0.00536 (9) | −0.00676 (9) |
N1 | 0.0214 (4) | 0.0168 (4) | 0.0133 (3) | −0.0032 (3) | −0.0052 (3) | −0.0050 (3) |
N2 | 0.0180 (3) | 0.0152 (3) | 0.0151 (3) | −0.0011 (3) | −0.0045 (3) | −0.0040 (3) |
N3 | 0.0161 (3) | 0.0148 (3) | 0.0147 (4) | −0.0021 (3) | −0.0037 (3) | −0.0034 (3) |
N10 | 0.0339 (5) | 0.0271 (4) | 0.0221 (4) | −0.0047 (4) | −0.0103 (4) | −0.0089 (3) |
N20 | 0.0331 (5) | 0.0306 (5) | 0.0226 (4) | −0.0048 (4) | −0.0063 (4) | −0.0072 (4) |
C1 | 0.0191 (4) | 0.0165 (4) | 0.0173 (4) | −0.0043 (3) | −0.0055 (3) | −0.0011 (3) |
C2 | 0.0209 (4) | 0.0174 (4) | 0.0225 (5) | −0.0040 (3) | −0.0042 (3) | −0.0034 (3) |
C3 | 0.0267 (5) | 0.0310 (5) | 0.0208 (5) | −0.0050 (4) | −0.0058 (4) | −0.0081 (4) |
C11 | 0.0143 (4) | 0.0150 (4) | 0.0149 (4) | 0.0006 (3) | −0.0045 (3) | −0.0033 (3) |
C12 | 0.0184 (4) | 0.0208 (4) | 0.0133 (4) | 0.0005 (3) | −0.0045 (3) | −0.0041 (3) |
C13 | 0.0188 (4) | 0.0211 (4) | 0.0158 (4) | −0.0002 (3) | −0.0027 (3) | 0.0006 (3) |
C14 | 0.0190 (4) | 0.0153 (4) | 0.0227 (5) | −0.0020 (3) | −0.0043 (3) | −0.0012 (3) |
C15 | 0.0188 (4) | 0.0160 (4) | 0.0187 (4) | −0.0012 (3) | −0.0049 (3) | −0.0053 (3) |
C21 | 0.0135 (4) | 0.0156 (4) | 0.0158 (4) | 0.0007 (3) | −0.0043 (3) | −0.0042 (3) |
C22 | 0.0165 (4) | 0.0170 (4) | 0.0205 (4) | −0.0019 (3) | −0.0054 (3) | −0.0065 (3) |
C23 | 0.0166 (4) | 0.0170 (4) | 0.0255 (5) | −0.0039 (3) | −0.0047 (3) | −0.0034 (3) |
C24 | 0.0178 (4) | 0.0211 (4) | 0.0183 (4) | −0.0041 (3) | −0.0021 (3) | −0.0004 (3) |
C25 | 0.0174 (4) | 0.0205 (4) | 0.0148 (4) | −0.0020 (3) | −0.0033 (3) | −0.0035 (3) |
S1—C1 | 1.6403 (10) | C12—C13 | 1.3773 (13) |
N1—C21 | 1.3564 (11) | C12—H12 | 0.9500 |
N1—C11 | 1.3920 (11) | C13—C14 | 1.3976 (13) |
N1—H71 | 0.903 (15) | C13—H13 | 0.9500 |
N2—C11 | 1.3334 (11) | C14—C15 | 1.3802 (13) |
N2—C15 | 1.3433 (11) | C14—H14 | 0.9500 |
N3—C21 | 1.3492 (11) | C15—H15 | 0.9500 |
N3—C25 | 1.3606 (11) | C21—C22 | 1.4116 (12) |
N3—H73 | 0.926 (15) | C22—C23 | 1.3696 (13) |
N10—C1 | 1.1659 (13) | C22—H22 | 0.9500 |
N20—C2 | 1.1418 (14) | C23—C24 | 1.4077 (13) |
C2—C3 | 1.4553 (13) | C23—H23 | 0.9500 |
C3—H31 | 0.9800 | C24—C25 | 1.3644 (13) |
C3—H32 | 0.9800 | C24—H24 | 0.9500 |
C3—H33 | 0.9800 | C25—H25 | 0.9500 |
C11—C12 | 1.4029 (12) | ||
C21—N1—C11 | 127.59 (8) | C14—C13—H13 | 120.3 |
C21—N1—H71 | 117.0 (9) | C15—C14—C13 | 118.25 (8) |
C11—N1—H71 | 115.3 (9) | C15—C14—H14 | 120.9 |
C11—N2—C15 | 117.74 (8) | C13—C14—H14 | 120.9 |
C21—N3—C25 | 122.32 (8) | N2—C15—C14 | 123.30 (8) |
C21—N3—H73 | 115.2 (9) | N2—C15—H15 | 118.3 |
C25—N3—H73 | 122.5 (9) | C14—C15—H15 | 118.3 |
N10—C1—S1 | 179.13 (9) | N3—C21—N1 | 120.87 (8) |
N20—C2—C3 | 179.23 (11) | N3—C21—C22 | 118.67 (8) |
C2—C3—H31 | 109.5 | N1—C21—C22 | 120.46 (8) |
C2—C3—H32 | 109.5 | C23—C22—C21 | 119.42 (8) |
H31—C3—H32 | 109.5 | C23—C22—H22 | 120.3 |
C2—C3—H33 | 109.5 | C21—C22—H22 | 120.3 |
H31—C3—H33 | 109.5 | C22—C23—C24 | 120.36 (8) |
H32—C3—H33 | 109.5 | C22—C23—H23 | 119.8 |
N2—C11—N1 | 117.54 (8) | C24—C23—H23 | 119.8 |
N2—C11—C12 | 123.26 (8) | C25—C24—C23 | 118.70 (8) |
N1—C11—C12 | 119.19 (8) | C25—C24—H24 | 120.6 |
C13—C12—C11 | 117.93 (8) | C23—C24—H24 | 120.6 |
C13—C12—H12 | 121.0 | N3—C25—C24 | 120.50 (8) |
C11—C12—H12 | 121.0 | N3—C25—H25 | 119.7 |
C12—C13—C14 | 119.46 (8) | C24—C25—H25 | 119.7 |
C12—C13—H13 | 120.3 | ||
C15—N2—C11—N1 | 177.96 (8) | C25—N3—C21—N1 | 179.52 (8) |
C15—N2—C11—C12 | −1.17 (13) | C25—N3—C21—C22 | −0.43 (12) |
C21—N1—C11—N2 | −0.70 (13) | C11—N1—C21—N3 | 0.43 (14) |
C21—N1—C11—C12 | 178.47 (8) | C11—N1—C21—C22 | −179.63 (8) |
N2—C11—C12—C13 | 2.30 (13) | N3—C21—C22—C23 | 1.40 (13) |
N1—C11—C12—C13 | −176.82 (8) | N1—C21—C22—C23 | −178.54 (8) |
C11—C12—C13—C14 | −1.38 (13) | C21—C22—C23—C24 | −1.21 (13) |
C12—C13—C14—C15 | −0.47 (13) | C22—C23—C24—C25 | 0.04 (14) |
C11—N2—C15—C14 | −0.87 (13) | C21—N3—C25—C24 | −0.76 (13) |
C13—C14—C15—N2 | 1.68 (14) | C23—C24—C25—N3 | 0.95 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H71···N10 | 0.903 (15) | 1.901 (15) | 2.8020 (11) | 176.4 (13) |
N3—H73···N2 | 0.926 (15) | 1.861 (15) | 2.6068 (11) | 135.9 (12) |
N3—H73···N20i | 0.926 (15) | 2.456 (15) | 3.1199 (12) | 128.7 (11) |
C25—H25···S1i | 0.95 | 2.83 | 3.5192 (9) | 130 |
Symmetry code: (i) x, y, z−1. |
Experimental details
Crystal data | |
Chemical formula | C10H10N3+·CNS−·C2H3N |
Mr | 271.34 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 100 |
a, b, c (Å) | 7.5450 (3), 7.8790 (3), 11.9900 (4) |
α, β, γ (°) | 76.849 (1), 75.211 (1), 81.371 (1) |
V (Å3) | 667.88 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.24 |
Crystal size (mm) | 0.54 × 0.40 × 0.34 |
Data collection | |
Diffractometer | Bruker APEXII CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.899, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11528, 3313, 3113 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.082, 1.07 |
No. of reflections | 3313 |
No. of parameters | 181 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.43, −0.20 |
Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H71···N10 | 0.903 (15) | 1.901 (15) | 2.8020 (11) | 176.4 (13) |
N3—H73···N2 | 0.926 (15) | 1.861 (15) | 2.6068 (11) | 135.9 (12) |
N3—H73···N20i | 0.926 (15) | 2.456 (15) | 3.1199 (12) | 128.7 (11) |
C25—H25···S1i | 0.95 | 2.83 | 3.5192 (9) | 130 |
Symmetry code: (i) x, y, z−1. |
Acknowledgements
The authors thank Mr David Neil-Schutte for helpful discussions.
References
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bock, H., Schödel, H., Van, T. T. H., Dienelt, R. & Gluth, M. (1998). J. Prakt. Chem. Chem. Zeitung, 340, 722–732. Web of Science CSD CrossRef CAS Google Scholar
Bruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Du, M. & Zhao, X.-J. (2004). Acta Cryst. E60, o439–o441. Web of Science CSD CrossRef IUCr Journals Google Scholar
Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262. CrossRef CAS Web of Science IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Gade, L. H. (1998). Koordinationschemie, 1. Auflage. Weinheim: Wiley-VCH. Google Scholar
Johnson, J. E. & Jacobson, R. A. (1973). Acta Cryst. B29, 1669–1674. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Junk, P. C., Wei-Min, L., Semenova, L. I., Skelton, B. W. & White, A. H. (2006). Z. Anorg. Allg. Chem. 632, 1303–1311. Web of Science CSD CrossRef CAS Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Pyrka, G. J. & Pinkerton, A. A. (1992). Acta Cryst. C48, 91–94. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Schödel, H., Näther, C., Bock, H. & Butenschön, F. (1996). Acta Cryst. B52, 842–853. CSD CrossRef Web of Science IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Chelate ligands have found widespread use in coordination chemistry due to the enhanced thermodynamic stability of resulting coordination compounds as compared to that of the complexes with exclusively monodentate ligands (Gade, 1998). Combining different sets of donor atoms in one chelate ligand molecule, allows to construct a probe for testing and accommodating metal centers of different Lewis acidities. In our efforts to synthesize a chelate ligand featuring a set of oxygen, sulfur and nitrogen as possible donor atoms, a crystalline reaction product was obtained whose crystal structure analysis revealed the unintentional synthesis of a salt of the starting material, dipyridin-2-ylamine. The crystal structure of free dipyridin-2-ylamine has been reported earlier (e.g. Johnson & Jacobson, 1973; Pyrka & Pinkerton, 1992; Schödel et al., 1996).
The studied compound was proved to be the thiocyanate salt of protonated dipyridin-2-ylamine (Fig. 1). Protonation occurs at one of the pyridine nitrogen atoms. The central nitrogen atom has a nearly trigonal-planar molecular geometry with H-N-C angles of 115.3 (9) °, 117.0 (9) ° and C-N-C angle of 127.59 (8) °. The aromatic systems are nearly coplanar, the least-squares planes defined by their respective atoms form very small dihedral angle of 1.99 (4) °. These observations are in good agreement with the geometrical parameters reported for similar compounds such as the chloride (Bock et al., 1998), the bromide (Junk et al., 2006) or the nitrate (Du & Zhao, 2004). In contrast to unprotonated dipyridine-2-ylamine, the title compound features the aromatic-ring-containing entity in a conformation with the pyridine nitrogen atoms facing each other. In addition, the pyridine moieties in neutral dipyridine-2-ylamine usually form dihedral angles well above 20 ° (Johnson & Jacobson, 1973); this difference is most probably due to the formation of an intramolecular hydrogen bond in the molecule of the title compound (Fig. 2; vide infra).
In the crystal structure, both nitrogen-bound hydrogen atoms take part in hydrogen bonds. While the nitrogen atom of the acetonitrile molecule serves as acceptor for the hydrogen bond originating from the protonated pyridyl moiety, the nitrogen atom of the thiocyanate anion serves as acceptor for the hydrogen bond involving the central NH group. Apart from these hydrogen bonds, the C-H···S contact, which is about 0.10 Å shorter than the sum of van-der-Waals radii of the corresponding atoms, exists in the crystal. These contacts originate from the H atom in ortho-position to the nitrogen atom in the protonated pyridyl moiety. As a result, all chemical residues of the crystal structure end up being linked into the infinite chains running along the crystallographic c axis (Fig. 2). In terms of graph-set analysis, (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the hydrogen bonding system on the unitary level is DD while the C-H···S contacts necessitate a D descriptor on the same level. Interaction between aromatic systems gives rise to π-stacking. The shortest intercentroid distance between two π-systems was measured at 3.6902 (6) Å and involves the protonated as well as the non-protonated pyridyl moiety. These connect the molecules into stacks along the a axis. The packing of the cystal of the title compound is shown in Fig. 3.