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

For complexes of disulfide derivatives, see Li *et al.* ( 2008[@bb4]). 

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

 {#sec2.1}

### Crystal data {#sec2.1.1}

C~16~H~10~O~8~S~2~*M* *~r~* = 394.36Monoclinic,*a* = 16.396 (3) Å*b* = 9.8462 (15) Å*c* = 20.363 (3) Åβ = 98.840 (2)°*V* = 3248.2 (9) Å^3^*Z* = 8Mo *K*α radiationμ = 0.37 mm^−1^*T* = 298 K0.48 × 0.21 × 0.03 mm

### Data collection {#sec2.1.2}

Bruker APEXII area-detector diffractometerAbsorption correction: multi-scan (*SADABS*; Sheldrick, 2004[@bb5]) *T* ~min~ = 0.831, *T* ~max~ = 0.98811095 measured reflections3027 independent reflections1992 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.039

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.047*wR*(*F* ^2^) = 0.140*S* = 1.033027 reflections239 parametersH-atom parameters constrainedΔρ~max~ = 0.53 e Å^−3^Δρ~min~ = −0.32 e Å^−3^

 {#d5e429}

Data collection: *APEX2* (Bruker, 2004[@bb1]); cell refinement: *SAINT* (Bruker, 2004[@bb1]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb6]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb6]); molecular graphics: *ORTEPIII* (Burnett & Johnson, 1996[@bb2]) and *ORTEP-3 for Windows* (Farrugia, 1997[@bb3]); software used to prepare material for publication: *SHELXL97*. 

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

Crystal structure: contains datablocks I, global.  DOI: [10.1107/S1600536809013622/cv2546sup1.cif](http://dx.doi.org/10.1107/S1600536809013622/cv2546sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536809013622/cv2546Isup2.hkl](http://dx.doi.org/10.1107/S1600536809013622/cv2546Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?cv2546&file=cv2546sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?cv2546sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?cv2546&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [CV2546](http://scripts.iucr.org/cgi-bin/sendsup?cv2546)). 

The author gratefully acknowledges financial support by the Youth Foundation of Lishui University, China (grant No.  QN05002). 

Comment
=======

The disulfide derivatives of the nicotinate - dithiodinicotinates - adopt usually a twisted structure with the C---S---S---C torsion of ca 90° in the solid state, that provides a possibility to show the axial chirality with M- and P-forms of the enantiomers (Li *et al.*,  2008).  Herewith we present the crystal structure of the title compound (Fig.  1), where torsion angle C---S---S---C is 91.80 (15)°. 

In the crystal, intermolecular O---H···O hydrogen bonds (Table 1) link the molecules into layers parallel to *ab* plane. 

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

2,2\'-Disulfanediylditerephthalic acid (0.40 mg, 0.1 mmol), Mn(CH3COO)2 (0.28 mg, 0.11 mmol), NaOH (25 mg, 0.06 mmol) were added in methanol.  The mixture was heated and stirred for six hours under reflux.  The resultant was then filtered off to give a pure solution which was treated by diethyl ether in a closed vessel.  One week later, single crystals were obtained. 

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

All H atoms attached to C atoms or O atoms were fixed geometrically and treated as riding with C---H = 0.93 Å (aromatic) or O---H = 0.82 Å (hydroxyl group) with U~iso~(H) = 1.2U~eq~.

Figures
=======

![ Molecular structure of (I), showing the atom-labelling scheme.  Displacement ellipsoids are drawn at the 30% probability level.  H atoms are represented as small spheres of arbitrary radii.](e-65-o1095-fig1){#Fap1}

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

  ----------------------- ---------------------------------------
  C~16~H~10~O~8~S~2~      *F*(000) = 1616
  *M~r~* = 394.36         *D*~x~ = 1.613 Mg m^−3^
  Monoclinic, *C*2/*c*    Mo *K*α radiation, λ = 0.71073 Å
  Hall symbol: -C 2yc     Cell parameters from 1947 reflections
  *a* = 16.396 (3) Å      θ = 2.4--25.6°
  *b* = 9.8462 (15) Å     µ = 0.37 mm^−1^
  *c* = 20.363 (3) Å      *T* = 298 K
  β = 98.840 (2)°         Block, colourless
  *V* = 3248.2 (9) Å^3^   0.48 × 0.21 × 0.03 mm
  *Z* = 8                 
  ----------------------- ---------------------------------------

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

  --------------------------------------------------------------- --------------------------------------
  Bruker APEXII area-detector diffractometer                      3027 independent reflections
  Radiation source: fine-focus sealed tube                        1992 reflections with *I* \> 2σ(*I*)
  graphite                                                        *R*~int~ = 0.039
  φ and ω scans                                                   θ~max~ = 25.5°, θ~min~ = 2.4°
  Absorption correction: multi-scan (*SADABS*; Sheldrick, 2004)   *h* = −19→19
  *T*~min~ = 0.831, *T*~max~ = 0.988                              *k* = −11→11
  11095 measured reflections                                      *l* = −24→24
  --------------------------------------------------------------- --------------------------------------

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*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.047   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.140                  H-atom parameters constrained
  *S* = 1.03                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0679*P*)^2^ + 4.4093*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  3027 reflections                      (Δ/σ)~max~ \< 0.001
  239 parameters                        Δρ~max~ = 0.53 e Å^−3^
  0 restraints                          Δρ~min~ = −0.32 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------------------

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

  ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Geometry.  All esds (except the esd in the dihedral angle between two l.s.  planes) are estimated using the full covariance matrix.  The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry.  An approximate (isotropic) treatment of cell esds is used for estimating esds 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^ \> 2sigma(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~   
  S1    0.26721 (5)     1.00797 (9)   0.25924 (4)    0.0312 (2)           
  S2    0.15066 (5)     1.01218 (9)   0.20597 (4)    0.0324 (2)           
  O1    0.41835 (14)    1.0121 (3)    0.32740 (12)   0.0477 (7)           
  O2    0.46882 (15)    0.9002 (3)    0.41908 (14)   0.0578 (8)           
  H2D   0.5089          0.9490        0.4171         0.087\*              
  O3    0.05065 (14)    0.6603 (3)    0.32417 (13)   0.0496 (7)           
  H3D   0.0114          0.6090        0.3250         0.074\*              
  O4    0.10411 (15)    0.5422 (3)    0.41363 (13)   0.0520 (7)           
  O5    0.00331 (15)    1.0344 (3)    0.13061 (14)   0.0539 (8)           
  O6    −0.05464 (15)   0.9000 (3)    0.04927 (14)   0.0506 (7)           
  H6D   −0.0924         0.9549        0.0482         0.076\*              
  O7    0.30978 (15)    0.5421 (3)    0.05144 (13)   0.0442 (7)           
  O8    0.36843 (15)    0.6784 (3)    0.13228 (15)   0.0591 (8)           
  H8D   0.4087          0.6302        0.1299         0.089\*              
  C1    0.33165 (18)    0.8542 (3)    0.37059 (15)   0.0254 (7)           
  C2    0.26309 (18)    0.8786 (3)    0.32073 (15)   0.0256 (7)           
  C3    0.19173 (18)    0.8031 (3)    0.32198 (15)   0.0267 (7)           
  H3A   0.1462          0.8166        0.2893         0.032\*              
  C4    0.18767 (18)    0.7073 (3)    0.37180 (15)   0.0267 (7)           
  C5    0.25458 (19)    0.6852 (3)    0.42111 (15)   0.0292 (7)           
  H5    0.2514          0.6215        0.4544         0.035\*              
  C6    0.32567 (19)    0.7586 (3)    0.42018 (15)   0.0305 (8)           
  H6    0.3707          0.7443        0.4532         0.037\*              
  C7    0.41062 (19)    0.9292 (3)    0.37033 (17)   0.0331 (8)           
  C8    0.11000 (19)    0.6282 (3)    0.37180 (16)   0.0306 (7)           
  C9    0.15409 (19)    0.8884 (3)    0.14229 (16)   0.0289 (7)           
  C10   0.08448 (18)    0.8614 (3)    0.09422 (15)   0.0292 (7)           
  C11   0.0880 (2)      0.7598 (3)    0.04614 (17)   0.0365 (8)           
  H11   0.0416          0.7418        0.0150         0.044\*              
  C12   0.1597 (2)      0.6863 (3)    0.04463 (17)   0.0344 (8)           
  H12   0.1616          0.6190        0.0129         0.041\*              
  C13   0.22814 (19)    0.7144 (3)    0.09087 (16)   0.0301 (7)           
  C14   0.22585 (18)    0.8129 (3)    0.13977 (16)   0.0300 (7)           
  H14   0.2725          0.8287        0.1710         0.036\*              
  C15   0.0074 (2)      0.9392 (3)    0.09224 (17)   0.0331 (8)           
  C16   0.30639 (19)    0.6367 (3)    0.08988 (16)   0.0319 (7)           
  ----- --------------- ------------- -------------- -------------------- --

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

  ----- ------------- ------------- ------------- -------------- -------------- --------------
        *U*^11^       *U*^22^       *U*^33^       *U*^12^        *U*^13^        *U*^23^
  S1    0.0270 (4)    0.0334 (5)    0.0317 (5)    −0.0071 (3)    −0.0001 (3)    0.0045 (3)
  S2    0.0282 (4)    0.0332 (5)    0.0347 (5)    0.0045 (4)     0.0013 (3)     −0.0017 (4)
  O1    0.0276 (13)   0.0655 (18)   0.0462 (15)   −0.0226 (12)   −0.0062 (11)   0.0224 (14)
  O2    0.0245 (14)   0.075 (2)     0.0660 (18)   −0.0225 (13)   −0.0174 (13)   0.0367 (15)
  O3    0.0268 (14)   0.0661 (19)   0.0513 (16)   −0.0234 (12)   −0.0079 (12)   0.0185 (13)
  O4    0.0292 (14)   0.0607 (17)   0.0616 (18)   −0.0227 (12)   −0.0072 (12)   0.0274 (14)
  O5    0.0308 (14)   0.0606 (18)   0.0651 (18)   0.0206 (13)    −0.0094 (12)   −0.0262 (15)
  O6    0.0270 (14)   0.0599 (18)   0.0594 (17)   0.0170 (12)    −0.0105 (12)   −0.0205 (14)
  O7    0.0339 (14)   0.0468 (15)   0.0514 (16)   0.0141 (11)    0.0055 (12)    −0.0084 (12)
  O8    0.0292 (15)   0.069 (2)     0.075 (2)     0.0203 (13)    −0.0069 (14)   −0.0258 (16)
  C1    0.0186 (16)   0.0304 (17)   0.0271 (16)   −0.0088 (13)   0.0029 (12)    −0.0036 (13)
  C2    0.0240 (16)   0.0262 (16)   0.0275 (17)   −0.0054 (13)   0.0066 (13)    −0.0019 (13)
  C3    0.0200 (16)   0.0313 (17)   0.0277 (17)   −0.0069 (13)   −0.0001 (13)   −0.0014 (13)
  C4    0.0213 (16)   0.0305 (17)   0.0289 (17)   −0.0072 (13)   0.0052 (13)    −0.0002 (13)
  C5    0.0263 (17)   0.0335 (18)   0.0280 (17)   −0.0079 (14)   0.0050 (13)    0.0047 (13)
  C6    0.0203 (17)   0.040 (2)     0.0294 (17)   −0.0068 (14)   −0.0039 (13)   0.0047 (14)
  C7    0.0228 (17)   0.039 (2)     0.0361 (19)   −0.0104 (15)   0.0010 (14)    0.0021 (15)
  C8    0.0226 (17)   0.0327 (19)   0.0366 (19)   −0.0100 (14)   0.0045 (14)    0.0016 (15)
  C9    0.0255 (17)   0.0286 (17)   0.0328 (18)   0.0003 (13)    0.0051 (14)    0.0031 (14)
  C10   0.0210 (17)   0.0333 (18)   0.0329 (18)   0.0030 (14)    0.0032 (13)    0.0008 (14)
  C11   0.0252 (18)   0.044 (2)     0.038 (2)     0.0059 (15)    −0.0012 (15)   −0.0051 (16)
  C12   0.0288 (18)   0.0374 (19)   0.0362 (19)   0.0068 (15)    0.0024 (15)    −0.0066 (15)
  C13   0.0262 (18)   0.0309 (18)   0.0333 (18)   0.0062 (14)    0.0048 (14)    0.0025 (14)
  C14   0.0186 (16)   0.0340 (18)   0.0361 (18)   0.0037 (13)    −0.0001 (14)   0.0028 (14)
  C15   0.0248 (18)   0.0357 (19)   0.0377 (19)   0.0070 (14)    0.0012 (15)    −0.0027 (15)
  C16   0.0242 (18)   0.0365 (19)   0.0348 (19)   0.0049 (14)    0.0042 (14)    0.0011 (15)
  ----- ------------- ------------- ------------- -------------- -------------- --------------

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

  ------------------- ------------- ----------------------- ------------
  S1---C2             1.795 (3)     C3---C4                 1.394 (4)
  S1---S2             2.0476 (11)   C3---H3A                0.9300
  S2---C9             1.787 (3)     C4---C5                 1.386 (4)
  O1---C7             1.217 (4)     C4---C8                 1.493 (4)
  O2---C7             1.299 (4)     C5---C6                 1.374 (4)
  O2---H2D            0.8200        C5---H5                 0.9300
  O3---C8             1.303 (4)     C6---H6                 0.9300
  O3---H3D            0.8200        C9---C14                1.399 (4)
  O4---C8             1.216 (4)     C9---C10                1.410 (4)
  O5---C15            1.229 (4)     C10---C11               1.407 (4)
  O6---C15            1.295 (4)     C10---C15               1.473 (4)
  O6---H6D            0.8200        C11---C12               1.384 (4)
  O7---C16            1.223 (4)     C11---H11               0.9300
  O8---C16            1.296 (4)     C12---C13               1.378 (4)
  O8---H8D            0.8200        C12---H12               0.9300
  C1---C6             1.395 (4)     C13---C14               1.395 (4)
  C1---C2             1.415 (4)     C13---C16               1.497 (4)
  C1---C7             1.491 (4)     C14---H14               0.9300
  C2---C3             1.390 (4)                             
                                                            
  C2---S1---S2        104.58 (10)   O4---C8---O3            124.0 (3)
  C9---S2---S1        103.87 (11)   O4---C8---C4            121.5 (3)
  C7---O2---H2D       109.5         O3---C8---C4            114.4 (3)
  C8---O3---H3D       109.5         C14---C9---C10          118.0 (3)
  C15---O6---H6D      109.5         C14---C9---S2           120.6 (2)
  C16---O8---H8D      109.5         C10---C9---S2           121.3 (2)
  C6---C1---C2        119.9 (3)     C11---C10---C9          120.1 (3)
  C6---C1---C7        119.6 (3)     C11---C10---C15         118.5 (3)
  C2---C1---C7        120.5 (3)     C9---C10---C15          121.4 (3)
  C3---C2---C1        118.3 (3)     C12---C11---C10         120.8 (3)
  C3---C2---S1        121.0 (2)     C12---C11---H11         119.6
  C1---C2---S1        120.7 (2)     C10---C11---H11         119.6
  C2---C3---C4        120.6 (3)     C13---C12---C11         119.0 (3)
  C2---C3---H3A       119.7         C13---C12---H12         120.5
  C4---C3---H3A       119.7         C11---C12---H12         120.5
  C5---C4---C3        120.8 (3)     C12---C13---C14         121.2 (3)
  C5---C4---C8        119.9 (3)     C12---C13---C16         119.9 (3)
  C3---C4---C8        119.3 (3)     C14---C13---C16         118.8 (3)
  C6---C5---C4        119.1 (3)     C13---C14---C9          120.7 (3)
  C6---C5---H5        120.5         C13---C14---H14         119.7
  C4---C5---H5        120.5         C9---C14---H14          119.7
  C5---C6---C1        121.3 (3)     O5---C15---O6           122.9 (3)
  C5---C6---H6        119.4         O5---C15---C10          120.7 (3)
  C1---C6---H6        119.4         O6---C15---C10          116.4 (3)
  O1---C7---O2        123.5 (3)     O7---C16---O8           124.0 (3)
  O1---C7---C1        121.4 (3)     O7---C16---C13          121.4 (3)
  O2---C7---C1        115.1 (3)     O8---C16---C13          114.6 (3)
                                                            
  C2---S1---S2---C9   −88.20 (15)   S1---S2---C9---C14      1.9 (3)
  C6---C1---C2---C3   −1.5 (4)      S1---S2---C9---C10      −179.6 (2)
  C7---C1---C2---C3   178.1 (3)     C14---C9---C10---C11    0.9 (5)
  C6---C1---C2---S1   176.3 (2)     S2---C9---C10---C11     −177.6 (3)
  C7---C1---C2---S1   −4.1 (4)      C14---C9---C10---C15    −178.1 (3)
  S2---S1---C2---C3   2.9 (3)       S2---C9---C10---C15     3.4 (4)
  S2---S1---C2---C1   −174.9 (2)    C9---C10---C11---C12    −0.9 (5)
  C1---C2---C3---C4   1.0 (5)       C15---C10---C11---C12   178.2 (3)
  S1---C2---C3---C4   −176.9 (2)    C10---C11---C12---C13   −0.3 (5)
  C2---C3---C4---C5   0.0 (5)       C11---C12---C13---C14   1.4 (5)
  C2---C3---C4---C8   179.8 (3)     C11---C12---C13---C16   −179.7 (3)
  C3---C4---C5---C6   −0.4 (5)      C12---C13---C14---C9    −1.4 (5)
  C8---C4---C5---C6   179.8 (3)     C16---C13---C14---C9    179.7 (3)
  C4---C5---C6---C1   −0.2 (5)      C10---C9---C14---C13    0.2 (5)
  C2---C1---C6---C5   1.2 (5)       S2---C9---C14---C13     178.8 (2)
  C7---C1---C6---C5   −178.4 (3)    C11---C10---C15---O5    −175.4 (3)
  C6---C1---C7---O1   179.1 (3)     C9---C10---C15---O5     3.6 (5)
  C2---C1---C7---O1   −0.5 (5)      C11---C10---C15---O6    5.8 (5)
  C6---C1---C7---O2   −1.5 (5)      C9---C10---C15---O6     −175.2 (3)
  C2---C1---C7---O2   178.9 (3)     C12---C13---C16---O7    −4.7 (5)
  C5---C4---C8---O4   −1.4 (5)      C14---C13---C16---O7    174.2 (3)
  C3---C4---C8---O4   178.8 (3)     C12---C13---C16---O8    175.0 (3)
  C5---C4---C8---O3   178.2 (3)     C14---C13---C16---O8    −6.1 (5)
  C3---C4---C8---O3   −1.6 (5)                              
  ------------------- ------------- ----------------------- ------------

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

  -------------------- --------- --------- ----------- ---------------
  *D*---H···*A*        *D*---H   H···*A*   *D*···*A*   *D*---H···*A*
  O8---H8D···O5^i^     0.82      1.81      2.632 (3)   174
  O6---H6D···O7^ii^    0.82      1.83      2.633 (3)   166
  O3---H3D···O1^iii^   0.82      1.81      2.623 (3)   174
  O2---H2D···O4^iv^    0.82      1.82      2.639 (3)   174
  -------------------- --------- --------- ----------- ---------------

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

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*          *D*---H   H⋯*A*   *D*⋯*A*     *D*---H⋯*A*
  -------------------- --------- ------- ----------- -------------
  O8---H8*D*⋯O5^i^     0.82      1.81    2.632 (3)   174
  O6---H6*D*⋯O7^ii^    0.82      1.83    2.633 (3)   166
  O3---H3*D*⋯O1^iii^   0.82      1.81    2.623 (3)   174
  O2---H2*D*⋯O4^iv^    0.82      1.82    2.639 (3)   174

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