Related literature {#sec1}
==================

For background to Schiff bases derived from thio­semicarbazone and its derivatives, see: Casas *et al.* (2001[@bb5]); Beraldo *et al.* (2001[@bb2]); Jouad *et al.* (2002[@bb6]); Swearingen *et al.* (2002[@bb12]). For bond-length data, see: Allen *et al.* (1987[@bb1]). For similar structures, see: Selvanayagam *et al.* (2002[@bb9]); Karakurt *et al.* (2003[@bb7]); Bernhardt *et al.* (2003[@bb3]); Sampath *et al.* (2003[@bb8]).

Experimental {#sec2}
============

 {#sec2.1}

### Crystal data {#sec2.1.1}

C~8~H~10~N~4~S*M* *~r~* = 194.26Monoclinic,*a* = 7.276 (3) Å*b* = 6.581 (2) Å*c* = 10.297 (3) Åβ = 92.997 (2)°*V* = 492.4 (3) Å^3^*Z* = 2Mo *K*α radiationμ = 0.29 mm^−1^*T* = 298 K0.17 × 0.15 × 0.15 mm

### Data collection {#sec2.1.2}

Bruker APEXII CCD diffractometerAbsorption correction: multi-scan (*SADABS*; Sheldrick, 2004[@bb10]) *T* ~min~ = 0.953, *T* ~max~ = 0.9583208 measured reflections1106 independent reflections640 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.041

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.043*wR*(*F* ^2^) = 0.118*S* = 1.021106 reflections84 parameters2 restraintsH atoms treated by a mixture of independent and constrained refinementΔρ~max~ = 0.14 e Å^−3^Δρ~min~ = −0.20 e Å^−3^

 {#d5e427}

Data collection: *APEX2* (Bruker, 2004[@bb4]); cell refinement: *SAINT* (Bruker, 2004[@bb4]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb11]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb11]); molecular graphics: *SHELXTL* (Sheldrick, 2008[@bb11]); software used to prepare material for publication: *SHELXTL*.

Supplementary Material
======================

Crystal structure: contains datablocks global, I. DOI: [10.1107/S1600536810048853/hb5755sup1.cif](http://dx.doi.org/10.1107/S1600536810048853/hb5755sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536810048853/hb5755Isup2.hkl](http://dx.doi.org/10.1107/S1600536810048853/hb5755Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?hb5755&file=hb5755sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?hb5755sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?hb5755&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [HB5755](http://scripts.iucr.org/cgi-bin/sendsup?hb5755)).

Comment
=======

Thiosemicarbazone and its derivatives are important materials for the preparation of Schiff bases (Casas *et al.*, 2001; Beraldo *et al.*, 2001; Jouad *et al.*, 2002; Swearingen *et al.*, 2002). In this paper, the title new Schiff base compound derived from the condensation of 3-formylpyridine with 4-methylthiosemicarbazone is reported.

The molecule of the title compound, Fig. 1, possess a crystallographic mirror plane symmetry. The bond lengths have normal values (Allen *et al.*, 1987), and are comparable to those observed in similar compounds (Selvanayagam *et al.*, 2002; Karakurt *et al.*, 2003; Bernhardt *et al.*, 2003; Sampath *et al.*, 2003).

In the crystal, molecules are linked through intermolecular N---H···N hydrogen bonds (Table 1), to form zigzag chains along the *a* axis (Fig. 2).

Experimental {#experimental}
============

The title compound was prepared by the Schiff base condensation of equimolar quantities of 3-formylpyridine (0.107 g, 1 mmol) with 4-methylthiosemicarbazone (0.105 g, 1 mmol) in methanol. The excess methanol was removed by distillation. Colourless blocks were obtained by slow evaporation of an ethanol solution of the product in air.

Refinement {#refinement}
==========

The amino H atoms were located in a difference map and refined with N---H distance restrained to 0.90 (1) Å. The remaining H atoms were positioned geometrically (C---H = 0.93--0.96 Å) and refined using a riding model, with *U*~iso~(H) = 1.2*U*~eq~(C) and 1.5*U*~eq~(C8).

Figures
=======

![The molecular structure of the title compound, showing 30% probability displacement ellipsoids.](e-66-o3324-fig1){#Fap1}

![The crystal packing of the title compound, viewed along the b axis.](e-66-o3324-fig2){#Fap2}

Crystal data {#tablewrapcrystaldatalong}
============

  ------------------------- --------------------------------------
  C~8~H~10~N~4~S            *F*(000) = 204
  *M~r~* = 194.26           *D*~x~ = 1.310 Mg m^−3^
  Monoclinic, *P*2~1~/*m*   Mo *K*α radiation, λ = 0.71073 Å
  Hall symbol: -P 2yb       Cell parameters from 669 reflections
  *a* = 7.276 (3) Å         θ = 2.7--24.5°
  *b* = 6.581 (2) Å         µ = 0.29 mm^−1^
  *c* = 10.297 (3) Å        *T* = 298 K
  β = 92.997 (2)°           Block, colourless
  *V* = 492.4 (3) Å^3^      0.17 × 0.15 × 0.15 mm
  *Z* = 2                   
  ------------------------- --------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  --------------------------------------------------------------- -------------------------------------
  Bruker APEXII CCD diffractometer                                1106 independent reflections
  Radiation source: fine-focus sealed tube                        640 reflections with *I* \> 2σ(*I*)
  graphite                                                        *R*~int~ = 0.041
  ω scans                                                         θ~max~ = 26.5°, θ~min~ = 2.8°
  Absorption correction: multi-scan (*SADABS*; Sheldrick, 2004)   *h* = −9→9
  *T*~min~ = 0.953, *T*~max~ = 0.958                              *k* = −8→8
  3208 measured reflections                                       *l* = −12→10
  --------------------------------------------------------------- -------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- -------------------------------------------------------------------------------------
  Refinement on *F*^2^                  Primary atom site location: structure-invariant direct methods
  Least-squares matrix: full            Secondary atom site location: difference Fourier map
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.043   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.118                  H atoms treated by a mixture of independent and constrained refinement
  *S* = 1.02                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0547*P*)^2^\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  1106 reflections                      (Δ/σ)~max~ \< 0.001
  84 parameters                         Δρ~max~ = 0.14 e Å^−3^
  2 restraints                          Δρ~min~ = −0.19 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------

Special details {#specialdetails}
===============

  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  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 *F*^2^ against ALL reflections. The weighted *R*-factor *wR* and goodness of fit *S* are based on *F*^2^, conventional *R*-factors *R* are based on *F*, with *F* set to zero for negative *F*^2^. The threshold expression of *F*^2^ \> σ(*F*^2^) is used only for calculating *R*-factors(gt) *etc*. and is not relevant to the choice of reflections for refinement. *R*-factors based on *F*^2^ 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 (Å^2^) {#tablewrapcoords}
==================================================================================================

  ----- -------------- -------- ------------- -------------------- ------------
        *x*            *y*      *z*           *U*~iso~\*/*U*~eq~   Occ. (\<1)
  S1    0.68926 (12)   0.2500   0.29184 (9)   0.0835 (4)           
  N1    −0.2929 (3)    0.2500   −0.1051 (2)   0.0558 (7)           
  N2    0.2508 (3)     0.2500   0.0542 (2)    0.0507 (6)           
  N3    0.4324 (3)     0.2500   0.1009 (2)    0.0566 (7)           
  N4    0.3217 (4)     0.2500   0.3028 (3)    0.0699 (8)           
  C1    0.0350 (3)     0.2500   −0.1287 (3)   0.0496 (7)           
  C2    −0.1201 (3)    0.2500   −0.0547 (3)   0.0510 (8)           
  H2    −0.1020        0.2500   0.0354        0.061\*              
  C3    −0.3159 (4)    0.2500   −0.2351 (3)   0.0616 (9)           
  H3A   −0.4353        0.2500   −0.2720       0.074\*              
  C4    −0.1733 (4)    0.2500   −0.3164 (3)   0.0697 (10)          
  H4A   −0.1954        0.2500   −0.4061       0.084\*              
  C5    0.0049 (4)     0.2500   −0.2620 (3)   0.0673 (10)          
  H5    0.1041         0.2500   −0.3154       0.081\*              
  C6    0.2213 (4)     0.2500   −0.0687 (3)   0.0581 (8)           
  H6    0.3209         0.2500   −0.1217       0.070\*              
  C7    0.4698 (4)     0.2500   0.2318 (3)    0.0554 (8)           
  C8    0.3272 (5)     0.2500   0.4451 (3)    0.0994 (13)          
  H8A   0.3310         0.1125   0.4762        0.149\*              0.50
  H8B   0.2193         0.3162   0.4743        0.149\*              0.50
  H8C   0.4349         0.3213   0.4781        0.149\*              0.50
  H3    0.519 (3)      0.2500   0.042 (2)     0.080\*              
  H4    0.212 (2)      0.2500   0.259 (3)     0.080\*              
  ----- -------------- -------- ------------- -------------------- ------------

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ---- ------------- ------------- ------------- --------- -------------- ---------
       *U*^11^       *U*^22^       *U*^33^       *U*^12^   *U*^13^        *U*^23^
  S1   0.0681 (6)    0.1189 (9)    0.0617 (6)    0.000     −0.0150 (4)    0.000
  N1   0.0392 (13)   0.0640 (17)   0.0642 (17)   0.000     0.0028 (12)    0.000
  N2   0.0365 (12)   0.0615 (16)   0.0542 (15)   0.000     0.0019 (11)    0.000
  N3   0.0416 (13)   0.0775 (18)   0.0508 (16)   0.000     0.0024 (11)    0.000
  N4   0.0738 (18)   0.085 (2)     0.0518 (16)   0.000     0.0136 (14)    0.000
  C1   0.0369 (14)   0.0618 (19)   0.0503 (17)   0.000     0.0058 (12)    0.000
  C2   0.0425 (15)   0.0593 (19)   0.0512 (18)   0.000     0.0011 (13)    0.000
  C3   0.0450 (16)   0.074 (2)     0.064 (2)     0.000     −0.0062 (15)   0.000
  C4   0.0587 (19)   0.102 (3)     0.0478 (19)   0.000     −0.0054 (16)   0.000
  C5   0.0505 (18)   0.097 (3)     0.055 (2)     0.000     0.0091 (15)    0.000
  C6   0.0389 (15)   0.078 (2)     0.0579 (19)   0.000     0.0108 (13)    0.000
  C7   0.0624 (19)   0.0541 (19)   0.0499 (18)   0.000     0.0033 (15)    0.000
  C8   0.126 (3)     0.121 (4)     0.053 (2)     0.000     0.023 (2)      0.000
  ---- ------------- ------------- ------------- --------- -------------- ---------

Geometric parameters (Å, °) {#tablewrapgeomlong}
===========================

  --------------- ------------ ---------------- -----------
  S1---C7         1.682 (3)    C1---C6          1.460 (4)
  N1---C2         1.335 (3)    C2---H2          0.9300
  N1---C3         1.340 (3)    C3---C4          1.367 (4)
  N2---C6         1.273 (4)    C3---H3A         0.9300
  N2---N3         1.382 (3)    C4---C5          1.385 (4)
  N3---C7         1.361 (4)    C4---H4A         0.9300
  N3---H3         0.899 (10)   C5---H5          0.9300
  N4---C7         1.334 (4)    C6---H6          0.9300
  N4---C8         1.463 (4)    C8---H8A         0.9600
  N4---H4         0.898 (10)   C8---H8B         0.9600
  C1---C5         1.379 (4)    C8---H8C         0.9600
  C1---C2         1.394 (4)                     
                                                
  C2---N1---C3    117.0 (2)    C3---C4---H4A    120.8
  C6---N2---N3    117.1 (2)    C5---C4---H4A    120.8
  C7---N3---N2    118.9 (2)    C1---C5---C4     119.9 (3)
  C7---N3---H3    124 (2)      C1---C5---H5     120.0
  N2---N3---H3    117 (2)      C4---C5---H5     120.0
  C7---N4---C8    124.7 (3)    N2---C6---C1     121.7 (3)
  C7---N4---H4    117 (2)      N2---C6---H6     119.2
  C8---N4---H4    119 (2)      C1---C6---H6     119.2
  C5---C1---C2    117.0 (2)    N4---C7---N3     114.7 (3)
  C5---C1---C6    121.1 (3)    N4---C7---S1     125.2 (2)
  C2---C1---C6    121.9 (3)    N3---C7---S1     120.1 (2)
  N1---C2---C1    124.1 (2)    N4---C8---H8A    109.5
  N1---C2---H2    118.0        N4---C8---H8B    109.5
  C1---C2---H2    118.0        H8A---C8---H8B   109.5
  N1---C3---C4    123.6 (3)    N4---C8---H8C    109.5
  N1---C3---H3A   118.2        H8A---C8---H8C   109.5
  C4---C3---H3A   118.2        H8B---C8---H8C   109.5
  C3---C4---C5    118.5 (3)                     
  --------------- ------------ ---------------- -----------

Hydrogen-bond geometry (Å, °) {#tablewraphbondslong}
=============================

  ----------------- ---------- ---------- ----------- ---------------
  *D*---H···*A*     *D*---H    H···*A*    *D*···*A*   *D*---H···*A*
  N4---H4···N2      0.90 (2)   2.14 (3)   2.585 (4)   109 (2)
  N3---H3···N1^i^   0.90 (1)   2.09 (1)   2.989 (3)   176 (3)
  ----------------- ---------- ---------- ----------- ---------------

Symmetry codes: (i) *x*+1, *y*, *z*.

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*     *D*---H    H⋯*A*      *D*⋯*A*     *D*---H⋯*A*
  --------------- ---------- ---------- ----------- -------------
  N4---H4⋯N2      0.90 (2)   2.14 (3)   2.585 (4)   109 (2)
  N3---H3⋯N1^i^   0.90 (1)   2.09 (1)   2.989 (3)   176 (3)

Symmetry code: (i) .
