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

For medicinal applications of coumarin derivatives, see: Lin *et al.* (2006[@bb5]); Massimo *et al.* (2003[@bb7]); Tyagi *et al.* (2003[@bb13]); Nawrot-Modranka *et al.* (2006[@bb8]); Sardari *et al.* (1999[@bb10]); Huang *et al.* (2005[@bb4]); Elinos-Baez *et al.* (2005[@bb3]). For the synthesis of the title compound, see: Ali & Ilyas (1986[@bb1]). For a similar structure, see: Pereira Silva *et al.* (2010[@bb9]).

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

 {#sec2.1}

### Crystal data {#sec2.1.1}

C~12~H~11~IO~4~*M* *~r~* = 346.11Triclinic,*a* = 7.1103 (7) Å*b* = 9.5825 (10) Å*c* = 9.9866 (9) Åα = 109.645 (5)°β = 94.734 (5)°γ = 104.060 (5)°*V* = 611.50 (10) Å^3^*Z* = 2Mo *K*α radiationμ = 2.62 mm^−1^*T* = 293 K0.30 × 0.18 × 0.13 mm

### Data collection {#sec2.1.2}

Bruker APEXII CCD area-detector diffractometerAbsorption correction: multi-scan (*SADABS*; Sheldrick, 2003[@bb11]) *T* ~min~ = 0.511, *T* ~max~ = 0.71217329 measured reflections2970 independent reflections2701 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.025

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.021*wR*(*F* ^2^) = 0.090*S* = 1.282970 reflections157 parametersH-atom parameters constrainedΔρ~max~ = 0.75 e Å^−3^Δρ~min~ = −0.59 e Å^−3^

 {#d5e453}

Data collection: *APEX2* (Bruker, 2003[@bb2]); cell refinement: *SAINT* (Bruker, 2003[@bb2]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb12]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb12]); molecular graphics: *Mercury* (Macrae *et al.*, 2006[@bb6]); software used to prepare material for publication: *SHELXL97*.

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

Crystal structure: contains datablocks global, I. DOI: [10.1107/S1600536811007549/fj2395sup1.cif](http://dx.doi.org/10.1107/S1600536811007549/fj2395sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536811007549/fj2395Isup2.hkl](http://dx.doi.org/10.1107/S1600536811007549/fj2395Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?fj2395&file=fj2395sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?fj2395sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?fj2395&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [FJ2395](http://scripts.iucr.org/cgi-bin/sendsup?fj2395)).

This work was supported by the Fundação para a Ciência e a Tecnologia (FCT) under scholarship SFRH/BD/38387/2008.

Comment
=======

Coumarin is the simplest member of the group of oxygen heterocyclics called benzo-2-pyrone. Coumarins are an important class of compounds due to their presence in natural products as well as their medicinal applications such as anti-inflammatory (Lin *et al.*, 2006), anti-viral (Massimo *et al.*, 2003), antioxidant (Tyagi *et al.*, 2003), antibacterial (Nawrot-Modranka *et al.*, 2006), antifungal (Sardari *et al.*, 1999), anti-HIV (Huang *et al.*, 2005) and as anti-carcinogenic (Elinos-Baez *et al.*, 2005). Besides the wide spectrum of biological applications of coumarin and its derivatives, there are also applications as cosmetics, optical brightening agents, and laser dyes. A recent report has revealed the anion sensing ability of some coumarin derivatives. Among various coumarin derivatives, recent pharmacological evaluation of iodocoumarins as cannabinoid receptor antagonists and inverse agonists has been done. Iodocoumarins such as 8-iodo-7-hydroxycoumarin exhibited moderate activity and 8-iodo-5,7-dihydroxycoumarin displayed good antimicrobial properties with MIC values \<100 µg/ml. Also, iodocoumarins had been successfully used for the optimization of reaction conditions and kinetic studies in high throughput format. Because of the biological and pharmaceutical importance of iodocoumarins, several protocols for the synthesis have been reported.

In the light of the mentioned above we planned to synthesize iodocoumarins by reaction of 5,7-dimethoxy-4-methylcoumarin with iodine in basic media (Ali & Ilyas, 1986).

In the molecule of the title compound (Fig. 1), the best plane through the aromatic ring shows an r.m.s. deviation of 0.0059 Å; the O1---C2---C3---C4---C10---C9 ring shows a larger deviation from planarity, with an r.m.s. deviation of 0.0279 Å. The angle between these two planes is 2.85 (5)°.

The C2 atom of the carbonyl group has a distorted trigonal geometry with O2---C2---O1 \[116.5 (3)°\] and O2---C2---C3 \[127.3 (23)°\] deviating significantly from the ideal *sp*^2^ value of 120°.

The methoxy groups are almost in the same plane as the aromatic ring, as indicated by the torsion angles C12---O3---C5---C6 \[1.8 (4)°\] and C13---O4---C7---C6 \[0.3 (4)°\]. This contrasts with the geometry of 6,8-diiodo-5,7-dimethoxy-4-methylcoumarin (Pereira Silva *et al.*, 2010), where the methoxy groups are considerably out of this plane.

The iodine atom is approximately in the plane of the benzene ring and the methyl group is only slightly out of the pyrone ring plane.

In the crystal, the molecules are linked by very weak C---H···O hydrogen bonds and O···I contacts \[3.080 (2) Å.\]. There are no classic hydrogen bonds. The molecules are approximately parallel to (100), forming a layered structure (Fig. 2).

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

To a stirred solution of 5,7-dimethoxy-4-methylcoumarin (2.20 g, 10 mmol) in 15--20 ml of methanol containing 8.2 g KOH was dropwise added to a solution of I~2~ (2.56 g, 10 mmol) over a period of 30 min and stirred at room temperature for about 2 h. The reaction mixture was poured into water and residual iodine was removed by washing with sodium thiosulfate. On treatment with sodium thiosulfate we obtained a precipitate which was filtered and crystallized with CHCl~3~---MeOH as white crystals (300 mg, m.p. 490 K). This precipitate was identified as 6,8-Diiodo-5,7-dimethoxy-4-methylcoumarin (Pereira Silva *et al.*, 2010). The mother liquor showed the mixture of one major spot along with some minor impurity, which was removed by preparative thin layer chromatography (benzene:acetone; 3:2). The pure compound thus obtained was crystallized with CHCl~3~---MeOH as shining crystals of (I) (50 mg, m.p. 523 K).

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

All H atoms were located in a difference Fourier synthesis, placed in calculated positions and refined as riding on their parent atoms, using *SHELXL97* (Sheldrick, 2008) defaults.

Figures
=======

![A plot of the title compound. Displacement ellipsoids are drawn at the 50% probability level.](e-67-0o776-fig1){#Fap1}

![A packing diagram for (I), viewed down the a axis.](e-67-0o776-fig2){#Fap2}

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

  ------------------------ ---------------------------------------
  C~12~H~11~IO~4~          *Z* = 2
  *M~r~* = 346.11          *F*(000) = 336
  Triclinic, *P*1          *D*~x~ = 1.880 Mg m^−3^
  Hall symbol: -P 1        Melting point: 523 K
  *a* = 7.1103 (7) Å       Mo *K*α radiation, λ = 0.71073 Å
  *b* = 9.5825 (10) Å      Cell parameters from 5373 reflections
  *c* = 9.9866 (9) Å       θ = 2.6--28.2°
  α = 109.645 (5)°         µ = 2.62 mm^−1^
  β = 94.734 (5)°          *T* = 293 K
  γ = 104.060 (5)°         Irregular block, light pink
  *V* = 611.50 (10) Å^3^   0.30 × 0.18 × 0.13 mm
  ------------------------ ---------------------------------------

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

  --------------------------------------------------------------- --------------------------------------
  Bruker APEXII CCD area-detector diffractometer                  2970 independent reflections
  Radiation source: fine-focus sealed tube                        2701 reflections with *I* \> 2σ(*I*)
  graphite                                                        *R*~int~ = 0.025
  φ and ω scans                                                   θ~max~ = 28.3°, θ~min~ = 2.2°
  Absorption correction: multi-scan (*SADABS*; Sheldrick, 2003)   *h* = −9→9
  *T*~min~ = 0.511, *T*~max~ = 0.712                              *k* = −12→12
  17329 measured reflections                                      *l* = −13→13
  --------------------------------------------------------------- --------------------------------------

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*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.021   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.090                  H-atom parameters constrained
  *S* = 1.28                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0503*P*)^2^ + 0.1088*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  2970 reflections                      (Δ/σ)~max~ = 0.001
  157 parameters                        Δρ~max~ = 0.75 e Å^−3^
  0 restraints                          Δρ~min~ = −0.59 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~   
  I1     0.85918 (3)   0.28855 (2)   0.398380 (19)   0.04982 (11)         
  O1     0.7959 (3)    0.3031 (2)    0.0951 (2)      0.0420 (4)           
  O2     0.7759 (5)    0.4881 (3)    0.0176 (3)      0.0674 (7)           
  O3     0.6758 (4)    −0.2218 (2)   −0.2155 (2)     0.0476 (5)           
  O4     0.7788 (4)    −0.0678 (3)   0.3021 (2)      0.0473 (5)           
  C2     0.7757 (5)    0.3557 (4)    −0.0158 (4)     0.0463 (7)           
  C3     0.7564 (5)    0.2457 (4)    −0.1588 (3)     0.0448 (6)           
  H3     0.7581        0.2808        −0.2350         0.054\*              
  C4     0.7360 (4)    0.0940 (3)    −0.1890 (3)     0.0378 (5)           
  C5     0.7146 (4)    −0.1155 (3)   −0.0803 (3)     0.0345 (5)           
  C6     0.7277 (4)    −0.1539 (3)   0.0418 (3)      0.0357 (5)           
  H6     0.7109        −0.2565       0.0317          0.043\*              
  C7     0.7659 (4)    −0.0396 (3)   0.1791 (3)      0.0359 (5)           
  C8     0.7918 (4)    0.1150 (3)    0.1944 (3)      0.0356 (5)           
  C9     0.7759 (4)    0.1501 (3)    0.0716 (3)      0.0335 (5)           
  C10    0.7408 (4)    0.0401 (3)    −0.0695 (3)     0.0328 (5)           
  C11    0.7118 (5)    −0.0087 (4)   −0.3441 (3)     0.0468 (7)           
  H11A   0.7269        0.0532        −0.4030         0.070\*              
  H11B   0.5830        −0.0819       −0.3742         0.070\*              
  H11C   0.8100        −0.0630       −0.3545         0.070\*              
  C12    0.6410 (6)    −0.3812 (4)   −0.2349 (4)     0.0552 (8)           
  H12A   0.7577        −0.3960       −0.1932         0.083\*              
  H12B   0.6080        −0.4433       −0.3362         0.083\*              
  H12C   0.5340        −0.4114       −0.1882         0.083\*              
  C13    0.7526 (6)    −0.2253 (4)   0.2918 (4)      0.0543 (8)           
  H13A   0.6194        −0.2857       0.2470          0.081\*              
  H13B   0.7790        −0.2272       0.3869          0.081\*              
  H13C   0.8418        −0.2677       0.2348          0.081\*              
  ------ ------------- ------------- --------------- -------------------- --

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

  ----- -------------- -------------- -------------- -------------- ------------- -------------
        *U*^11^        *U*^22^        *U*^33^        *U*^12^        *U*^13^       *U*^23^
  I1    0.06807 (17)   0.03768 (14)   0.03117 (13)   0.01100 (10)   0.00271 (9)   0.00155 (9)
  O1    0.0595 (12)    0.0256 (9)     0.0397 (11)    0.0125 (8)     0.0081 (9)    0.0105 (8)
  O2    0.110 (2)      0.0386 (13)    0.0677 (17)    0.0334 (14)    0.0261 (16)   0.0265 (13)
  O3    0.0788 (15)    0.0293 (10)    0.0298 (10)    0.0149 (10)    0.0061 (9)    0.0062 (8)
  O4    0.0766 (14)    0.0390 (11)    0.0294 (10)    0.0203 (10)    0.0069 (9)    0.0144 (9)
  C2    0.0567 (16)    0.0366 (15)    0.0523 (18)    0.0160 (12)    0.0147 (14)   0.0217 (14)
  C3    0.0577 (16)    0.0417 (16)    0.0433 (16)    0.0159 (13)    0.0127 (13)   0.0239 (13)
  C4    0.0415 (13)    0.0402 (14)    0.0350 (14)    0.0121 (11)    0.0082 (10)   0.0175 (12)
  C5    0.0409 (12)    0.0300 (12)    0.0297 (13)    0.0109 (10)    0.0054 (10)   0.0073 (10)
  C6    0.0454 (13)    0.0277 (12)    0.0340 (13)    0.0114 (10)    0.0070 (10)   0.0112 (10)
  C7    0.0422 (13)    0.0351 (13)    0.0314 (13)    0.0126 (10)    0.0052 (10)   0.0127 (11)
  C8    0.0429 (13)    0.0300 (12)    0.0296 (13)    0.0100 (10)    0.0043 (10)   0.0066 (10)
  C9    0.0366 (12)    0.0266 (12)    0.0346 (13)    0.0081 (9)     0.0057 (10)   0.0086 (10)
  C10   0.0385 (12)    0.0294 (12)    0.0295 (12)    0.0097 (10)    0.0059 (9)    0.0099 (10)
  C11   0.0625 (17)    0.0474 (17)    0.0293 (14)    0.0130 (14)    0.0084 (12)   0.0149 (13)
  C12   0.089 (2)      0.0292 (14)    0.0413 (17)    0.0170 (15)    0.0137 (16)   0.0049 (13)
  C13   0.087 (2)      0.0440 (17)    0.0436 (17)    0.0286 (17)    0.0147 (16)   0.0233 (15)
  ----- -------------- -------------- -------------- -------------- ------------- -------------

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

  --------------------- ------------- --------------------- ------------
  I1---C8               2.078 (3)     C6---C7               1.392 (4)
  O1---C2               1.374 (4)     C6---H6               0.9300
  O1---C9               1.374 (3)     C7---C8               1.401 (4)
  O2---C2               1.198 (4)     C8---C9               1.380 (4)
  O3---C5               1.346 (3)     C9---C10              1.405 (4)
  O3---C12              1.429 (4)     C11---H11A            0.9600
  O4---C7               1.345 (3)     C11---H11B            0.9600
  O4---C13              1.441 (4)     C11---H11C            0.9600
  C2---C3               1.433 (5)     C12---H12A            0.9600
  C3---C4               1.350 (4)     C12---H12B            0.9600
  C3---H3               0.9300        C12---H12C            0.9600
  C4---C10              1.452 (4)     C13---H13A            0.9600
  C4---C11              1.498 (4)     C13---H13B            0.9600
  C5---C6               1.389 (4)     C13---H13C            0.9600
  C5---C10              1.423 (4)                           
                                                            
  C2---O1---C9          122.5 (2)     O1---C9---C8          115.4 (2)
  C5---O3---C12         118.9 (2)     O1---C9---C10         120.7 (2)
  C7---O4---C13         118.3 (2)     C8---C9---C10         123.9 (2)
  O2---C2---O1          116.5 (3)     C9---C10---C5         115.6 (2)
  O2---C2---C3          127.3 (3)     C9---C10---C4         118.2 (2)
  O1---C2---C3          116.3 (2)     C5---C10---C4         126.3 (2)
  C4---C3---C2          123.6 (3)     C4---C11---H11A       109.5
  C4---C3---H3          118.2         C4---C11---H11B       109.5
  C2---C3---H3          118.2         H11A---C11---H11B     109.5
  C3---C4---C10         118.2 (3)     C4---C11---H11C       109.5
  C3---C4---C11         117.9 (3)     H11A---C11---H11C     109.5
  C10---C4---C11        123.9 (3)     H11B---C11---H11C     109.5
  O3---C5---C6          122.7 (2)     O3---C12---H12A       109.5
  O3---C5---C10         115.8 (2)     O3---C12---H12B       109.5
  C6---C5---C10         121.5 (2)     H12A---C12---H12B     109.5
  C5---C6---C7          120.3 (2)     O3---C12---H12C       109.5
  C5---C6---H6          119.8         H12A---C12---H12C     109.5
  C7---C6---H6          119.8         H12B---C12---H12C     109.5
  O4---C7---C6          123.8 (2)     O4---C13---H13A       109.5
  O4---C7---C8          116.3 (2)     O4---C13---H13B       109.5
  C6---C7---C8          119.9 (2)     H13A---C13---H13B     109.5
  C9---C8---C7          118.7 (2)     O4---C13---H13C       109.5
  C9---C8---I1          120.70 (19)   H13A---C13---H13C     109.5
  C7---C8---I1          120.6 (2)     H13B---C13---H13C     109.5
                                                            
  C9---O1---C2---O2     172.5 (3)     C2---O1---C9---C8     −177.2 (3)
  C9---O1---C2---C3     −7.4 (4)      C2---O1---C9---C10    2.5 (4)
  O2---C2---C3---C4     −172.5 (4)    C7---C8---C9---O1     177.7 (2)
  O1---C2---C3---C4     7.4 (5)       I1---C8---C9---O1     −3.7 (3)
  C2---C3---C4---C10    −2.2 (4)      C7---C8---C9---C10    −1.9 (4)
  C2---C3---C4---C11    178.4 (3)     I1---C8---C9---C10    176.7 (2)
  C12---O3---C5---C6    1.8 (4)       O1---C9---C10---C5    −177.5 (2)
  C12---O3---C5---C10   −177.9 (3)    C8---C9---C10---C5    2.1 (4)
  O3---C5---C6---C7     −179.2 (3)    O1---C9---C10---C4    3.0 (4)
  C10---C5---C6---C7    0.4 (4)       C8---C9---C10---C4    −177.3 (2)
  C13---O4---C7---C6    0.3 (4)       O3---C5---C10---C9    178.3 (2)
  C13---O4---C7---C8    179.8 (3)     C6---C5---C10---C9    −1.3 (4)
  C5---C6---C7---O4     179.3 (3)     O3---C5---C10---C4    −2.2 (4)
  C5---C6---C7---C8     −0.2 (4)      C6---C5---C10---C4    178.1 (3)
  O4---C7---C8---C9     −178.6 (2)    C3---C4---C10---C9    −3.1 (4)
  C6---C7---C8---C9     0.9 (4)       C11---C4---C10---C9   176.3 (3)
  O4---C7---C8---I1     2.8 (3)       C3---C4---C10---C5    177.5 (3)
  C6---C7---C8---I1     −177.7 (2)    C11---C4---C10---C5   −3.1 (4)
  --------------------- ------------- --------------------- ------------

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

  -------------------- --------- --------- ----------- ---------------
  *D*---H···*A*        *D*---H   H···*A*   *D*···*A*   *D*---H···*A*
  C6---H6···O2^i^      0.93      2.56      3.460 (4)   163
  C13---H13C···O2^i^   0.96      2.51      3.211 (5)   130
  -------------------- --------- --------- ----------- ---------------

Symmetry codes: (i) *x*, *y*−1, *z*.

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*          *D*---H   H⋯*A*   *D*⋯*A*     *D*---H⋯*A*
  -------------------- --------- ------- ----------- -------------
  C6---H6⋯O2^i^        0.93      2.56    3.460 (4)   163
  C13---H13*C*⋯O2^i^   0.96      2.51    3.211 (5)   130

Symmetry code: (i) .
