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

For a general background on the mol­ecular self-assembly of supra­molecular architectures, see: Mou *et al.* ( 2008[@bb2]); Moulton & Zaworotko (2001[@bb3]); Zeng *et al.* ( 2007[@bb6]). 

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

 {#sec2.1}

### Crystal data {#sec2.1.1}

\[Pr(C~6~H~4~NO~3~)(C~2~O~4~)(H~2~O)~2~\]*M* *~r~* = 403.06Triclinic,*a* = 7.5820 (19) Å*b* = 8.643 (2) Å*c* = 9.375 (4) Åα = 108.992 (4)°β = 103.925 (4)°γ = 102.043 (3)°*V* = 535.6 (3) Å^3^*Z* = 2Mo *K*α radiationμ = 4.60 mm^−1^*T* = 296 K0.19 × 0.17 × 0.16 mm

### Data collection {#sec2.1.2}

Bruker APEXII area-detector diffractometerAbsorption correction: multi-scan (*SADABS*; Sheldrick, 1996[@bb4]) *T* ~min~ = 0.435, *T* ~max~ = 0.4852751 measured reflections1888 independent reflections1753 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.024

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.030*wR*(*F* ^2^) = 0.080*S* = 1.101888 reflections187 parameters8 restraintsH atoms treated by a mixture of independent and constrained refinementΔρ~max~ = 1.06 e Å^−3^Δρ~min~ = −1.66 e Å^−3^

 {#d5e590}

Data collection: *APEX2* (Bruker, 2004[@bb1]); cell refinement: *APEX2*; data reduction: *SAINT* (Bruker, 2004[@bb1]); program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb5]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb5]); molecular graphics: *SHELXTL* (Sheldrick, 2008[@bb5]); software used to prepare material for publication: *SHELXL97*. 

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

Crystal structure: contains datablocks I, global.  DOI: [10.1107/S160053680900542X/rz2293sup1.cif](http://dx.doi.org/10.1107/S160053680900542X/rz2293sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S160053680900542X/rz2293Isup2.hkl](http://dx.doi.org/10.1107/S160053680900542X/rz2293Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?rz2293&file=rz2293sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?rz2293sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?rz2293&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [RZ2293](http://scripts.iucr.org/cgi-bin/sendsup?rz2293)). 

The authors gratefully acknowledge the financial support from the Emphasis Project sponsored by the Department of Education of Guangdong Province (No.  \[2007\]129). 

Comment
=======

Molecular self-assembly of supramolecular architectures has received much attention during recent decades (Zeng *et al.*,  2007; Moulton & Zaworotko, 2001; Mou *et al.*,  2008).  The structures and properties of such systems depend on the coordination and geometric preferences of both the central metal ions and the bridging building blocks, as well as the influence of weaker non-covalent interactions, such as hydrogen bonds and π-π stacking interactions.  Recently, we obtained the title coordination polymer, which was synthesized under hydrothermal conditions. 

As illustrated in Fig.  1, in the structure of the title compound each Pr^III^ centre is in a distorted bicapped square antiprismatic geometry, defined by eight oxygen atoms from two 2-oxynicotinate ligands, two oxalate ligands, and two water molecules The Pr^III^ ions are linked by 2-oxynicotinate ligands and oxalate ligands to form layers parallel to the *bc* plane (Fig.  2), with separations between adjacent Pr^III^ metal centres of 4.410 (4), 6.505 (5) and 6.551 (3) Å. Intermolecular O---H···O and N---H···O hydrogen bonding interactions (Table 1) involving the 2-oxynicotinate ligands, the oxalate ligands and the water molecules assemble neighboring layers to form a three-dimensional supramolecular network motif. 

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

A mixture of Pr~2~O~3~ (0.330 g; 1.0 mmol), 2-oxynicotinic acid (0.127 g; 1 mmol), oxalic acid(0.09 g; 1 mmol), water (10 ml) in the presence of HNO~3~ (0.024 g; 0.385 mmol) was stirred vigorously for 20 min and then sealed in a Teflon-lined stainless-steel autoclave (20 ml, capacity).  The autoclave was heated and maintained at 443 K for 3 days.  After cooling to room temperature at 5 K h^-1^, colourless block crystals of the title compound were obtained. 

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

Water H atoms were located in difference Fourier maps and were refined with distance restraints of O--H = 0.84 Å, H···H = 1.35 Å, and with *U*~iso~(H) = 1.5 *U*~eq~(O).  The separation between symmetry related H4W atoms at (*x*, *y*, *z*) and (1 - *x*, 1 - *y*, 2 - *z*) was restrained to be 2.2 Å. Carbon-bound H atoms were placed at calculated positions and were treated as riding on the parent C atoms with C---H = 0.93 Å, and with *U*~iso~(H) = 1.2 *U*~eq~(C).  The H atom bound to the N1 nitrogen atom was refined with a distance restraints of N--H = 0.86 Å and with *U*~iso~(H) = 1.2 *U*~eq~(N). 

Figures
=======

![ The molecular structure of the title compound showing the atom-numbering scheme.  Displacement ellipsoids are drawn at the 50% probability level.  Symmetry codes: (i) -x, 1 - y, 2 - z; (ii) -x, 1 - y, 1 - z; (iii) -x, 2 - y, 2 - z.](e-65-0m310-fig1){#Fap1}

![ Crystal structure of the title compound viewed approximately along the a axis.](e-65-0m310-fig2){#Fap2}

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

  ------------------------------------------- ---------------------------------------
  \[Pr(C~6~H~4~NO~3~)(C~2~O~4~)(H~2~O)~2~\]   *Z* = 2
  *M~r~* = 403.06                             *F*(000) = 388
  Triclinic, *P*1                             *D*~x~ = 2.499 Mg m^−3^
  Hall symbol: -P 1                           Mo *K*α radiation, λ = 0.71073 Å
  *a* = 7.5820 (19) Å                         Cell parameters from 2183 reflections
  *b* = 8.643 (2) Å                           θ = 2.6--28.0°
  *c* = 9.375 (4) Å                           µ = 4.60 mm^−1^
  α = 108.992 (4)°                            *T* = 296 K
  β = 103.925 (4)°                            Block, colourless
  γ = 102.043 (3)°                            0.19 × 0.17 × 0.16 mm
  *V* = 535.6 (3) Å^3^                        
  ------------------------------------------- ---------------------------------------

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

  --------------------------------------------------------------- --------------------------------------
  Bruker APEXII area-detector diffractometer                      1888 independent reflections
  Radiation source: fine-focus sealed tube                        1753 reflections with *I* \> 2σ(*I*)
  graphite                                                        *R*~int~ = 0.024
  φ and ω scans                                                   θ~max~ = 25.2°, θ~min~ = 2.4°
  Absorption correction: multi-scan (*SADABS*; Sheldrick, 1996)   *h* = −9→8
  *T*~min~ = 0.435, *T*~max~ = 0.485                              *k* = −6→10
  2751 measured reflections                                       *l* = −11→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*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.030   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.080                  H atoms treated by a mixture of independent and constrained refinement
  *S* = 1.10                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0483*P*)^2^ + 0.01*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  1888 reflections                      (Δ/σ)~max~ = 0.001
  187 parameters                        Δρ~max~ = 1.06 e Å^−3^
  8 restraints                          Δρ~min~ = −1.66 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~   
  Pr1   0.13688 (4)   0.65736 (3)   0.88899 (3)   0.01199 (13)         
  O1    0.1360 (5)    0.5899 (6)    1.1378 (4)    0.0209 (9)           
  O2    0.2431 (6)    0.4573 (6)    1.2882 (5)    0.0292 (10)          
  O3    0.4163 (6)    0.8435 (6)    1.1280 (4)    0.0255 (10)          
  O4    0.0792 (6)    0.7141 (5)    0.6359 (4)    0.0210 (9)           
  O5    −0.0653 (6)   0.5985 (5)    0.3701 (5)    0.0240 (9)           
  O6    0.1917 (5)    0.9740 (5)    0.9339 (5)    0.0211 (9)           
  O7    0.0683 (6)    1.1925 (5)    0.9755 (5)    0.0221 (9)           
  N1    0.6714 (7)    0.9795 (7)    1.3550 (6)    0.0213 (11)          
  H1    0.709 (9)     1.056 (6)     1.320 (7)     0.026\*              
  C1    0.2690 (8)    0.5814 (8)    1.2460 (6)    0.0184 (12)          
  C2    0.4526 (7)    0.7259 (7)    1.3291 (6)    0.0155 (11)          
  C3    0.5671 (8)    0.7451 (8)    1.4747 (7)    0.0226 (13)          
  H3    0.5331        0.6633        1.5160        0.027\*              
  C4    0.7339 (8)    0.8845 (9)    1.5629 (7)    0.0268 (14)          
  H4    0.8106        0.8963        1.6620        0.032\*              
  C5    0.7816 (8)    1.0019 (8)    1.5011 (7)    0.0260 (14)          
  H5    0.8900        1.0978        1.5591        0.031\*              
  C6    0.5042 (8)    0.8480 (8)    1.2612 (6)    0.0176 (12)          
  C7    0.0043 (7)    0.5910 (7)    0.5025 (6)    0.0169 (12)          
  C8    0.0756 (7)    1.0482 (7)    0.9731 (6)    0.0132 (11)          
  O1W   0.4579 (6)    0.7364 (7)    0.8300 (6)    0.0344 (11)          
  H1W   0.526 (8)     0.825 (6)     0.912 (6)     0.052\*              
  H2W   0.532 (7)     0.703 (9)     0.781 (7)     0.052\*              
  O2W   0.3042 (6)    0.4283 (6)    0.9073 (5)    0.0256 (9)           
  H3W   0.253 (9)     0.355 (5)     0.938 (6)     0.038\*              
  H4W   0.362 (3)     0.520 (3)     0.987 (4)     0.038\*              
  ----- ------------- ------------- ------------- -------------------- --

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

  ----- -------------- ------------ -------------- -------------- -------------- --------------
        *U*^11^        *U*^22^      *U*^33^        *U*^12^        *U*^13^        *U*^23^
  Pr1   0.01204 (18)   0.0123 (2)   0.01350 (19)   0.00367 (13)   0.00302 (12)   0.00841 (14)
  O1    0.0147 (19)    0.030 (3)    0.0152 (19)    0.0010 (18)    −0.0001 (16)   0.0128 (18)
  O2    0.030 (2)      0.023 (3)    0.031 (2)      −0.003 (2)     0.0026 (19)    0.019 (2)
  O3    0.0211 (19)    0.029 (3)    0.019 (2)      −0.0046 (18)   −0.0042 (16)   0.0153 (19)
  O4    0.031 (2)      0.015 (2)    0.0137 (19)    0.0041 (18)    0.0044 (17)    0.0060 (17)
  O5    0.040 (2)      0.016 (2)    0.016 (2)      0.0109 (19)    0.0039 (18)    0.0103 (18)
  O6    0.0183 (19)    0.019 (2)    0.035 (2)      0.0104 (18)    0.0150 (17)    0.0138 (19)
  O7    0.027 (2)      0.013 (2)    0.036 (2)      0.0079 (18)    0.0173 (18)    0.0158 (19)
  N1    0.019 (2)      0.019 (3)    0.025 (3)      0.002 (2)      0.003 (2)      0.012 (2)
  C1    0.023 (3)      0.019 (3)    0.013 (3)      0.006 (3)      0.005 (2)      0.006 (2)
  C2    0.015 (2)      0.018 (3)    0.015 (3)      0.004 (2)      0.006 (2)      0.008 (2)
  C3    0.026 (3)      0.028 (4)    0.018 (3)      0.009 (3)      0.007 (2)      0.016 (3)
  C4    0.020 (3)      0.035 (4)    0.019 (3)      0.005 (3)      −0.003 (2)     0.012 (3)
  C5    0.015 (3)      0.025 (4)    0.029 (3)      0.003 (3)      0.001 (2)      0.006 (3)
  C6    0.019 (3)      0.021 (3)    0.015 (3)      0.008 (2)      0.008 (2)      0.006 (2)
  C7    0.017 (3)      0.017 (3)    0.019 (3)      0.005 (2)      0.005 (2)      0.011 (2)
  C8    0.014 (2)      0.011 (3)    0.013 (3)      0.003 (2)      0.000 (2)      0.005 (2)
  O1W   0.025 (2)      0.035 (3)    0.034 (3)      0.000 (2)      0.0112 (19)    0.007 (2)
  O2W   0.025 (2)      0.030 (3)    0.033 (2)      0.015 (2)      0.0120 (18)    0.021 (2)
  ----- -------------- ------------ -------------- -------------- -------------- --------------

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

  ------------------------- ------------- --------------------- -------------
  Pr1---O3                  2.458 (4)     O7---C8               1.253 (7)
  Pr1---O4                  2.532 (4)     O7---Pr1^i^           2.537 (4)
  Pr1---O7^i^               2.537 (4)     N1---C5               1.350 (8)
  Pr1---O5^ii^              2.540 (4)     N1---C6               1.372 (8)
  Pr1---O1^iii^             2.543 (4)     N1---H1               0.86 (6)
  Pr1---O6                  2.555 (4)     C1---C2               1.491 (8)
  Pr1---O1                  2.583 (4)     C1---Pr1^iii^         3.018 (6)
  Pr1---O2W                 2.593 (4)     C2---C3               1.367 (8)
  Pr1---O1W                 2.626 (4)     C2---C6               1.434 (8)
  Pr1---O2^iii^             2.734 (4)     C3---C4               1.396 (8)
  Pr1---C1^iii^             3.018 (6)     C3---H3               0.9300
  Pr1---H4W                 2.44 (4)      C4---C5               1.352 (9)
  O1---C1                   1.280 (7)     C4---H4               0.9300
  O1---Pr1^iii^             2.543 (4)     C5---H5               0.9300
  O2---C1                   1.253 (7)     C7---C7^ii^           1.546 (11)
  O2---Pr1^iii^             2.734 (4)     C8---C8^i^            1.555 (10)
  O3---C6                   1.251 (7)     O1W---H1W             0.84 (5)
  O4---C7                   1.248 (7)     O1W---H2W             0.84 (5)
  O5---C7                   1.255 (6)     O2W---H3W             0.84 (5)
  O5---Pr1^ii^              2.540 (4)     O2W---H4W             0.83 (3)
  O6---C8                   1.249 (6)                           
                                                                
  O3---Pr1---O4             120.86 (13)   O4---Pr1---H4W        127.8 (11)
  O3---Pr1---O7^i^          88.47 (14)    O7^i^---Pr1---H4W     129.5 (10)
  O4---Pr1---O7^i^          102.37 (13)   O5^ii^---Pr1---H4W    81.2 (5)
  O3---Pr1---O5^ii^         137.09 (15)   O1^iii^---Pr1---H4W   88.8 (9)
  O4---Pr1---O5^ii^         63.36 (13)    O6---Pr1---H4W        129.1 (6)
  O7^i^---Pr1---O5^ii^      134.11 (14)   O1---Pr1---H4W        60.0 (11)
  O3---Pr1---O1^iii^        127.58 (12)   O2W---Pr1---H4W       18.7 (8)
  O4---Pr1---O1^iii^        111.40 (13)   O1W---Pr1---H4W       67.4 (11)
  O7^i^---Pr1---O1^iii^     76.36 (13)    O2^iii^---Pr1---H4W   134.2 (6)
  O5^ii^---Pr1---O1^iii^    70.57 (14)    C1^iii^---Pr1---H4W   111.2 (8)
  O3---Pr1---O6             69.27 (14)    C1---O1---Pr1^iii^    98.8 (3)
  O4---Pr1---O6             65.37 (13)    C1---O1---Pr1         131.9 (3)
  O7^i^---Pr1---O6          63.08 (12)    Pr1^iii^---O1---Pr1   118.71 (14)
  O5^ii^---Pr1---O6         128.42 (12)   C1---O2---Pr1^iii^    90.5 (3)
  O1^iii^---Pr1---O6        136.28 (12)   C6---O3---Pr1         140.0 (4)
  O3---Pr1---O1             66.31 (12)    C7---O4---Pr1         119.9 (3)
  O4---Pr1---O1             170.59 (12)   C7---O5---Pr1^ii^     120.3 (4)
  O7^i^---Pr1---O1          70.75 (13)    C8---O6---Pr1         120.7 (3)
  O5^ii^---Pr1---O1         116.45 (13)   C8---O7---Pr1^i^      121.3 (3)
  O1^iii^---Pr1---O1        61.29 (14)    C5---N1---C6          125.6 (5)
  O6---Pr1---O1             115.03 (13)   C5---N1---H1          116 (5)
  O3---Pr1---O2W            81.72 (14)    C6---N1---H1          118 (4)
  O4---Pr1---O2W            117.75 (13)   O2---C1---O1          120.7 (5)
  O7^i^---Pr1---O2W         137.99 (13)   O2---C1---C2          119.7 (5)
  O5^ii^---Pr1---O2W        63.32 (13)    O1---C1---C2          119.5 (5)
  O1^iii^---Pr1---O2W       77.80 (13)    O2---C1---Pr1^iii^    65.0 (3)
  O6---Pr1---O2W            144.55 (13)   O1---C1---Pr1^iii^    56.4 (3)
  O1---Pr1---O2W            67.88 (13)    C2---C1---Pr1^iii^    168.4 (4)
  O3---Pr1---O1W            65.67 (14)    C3---C2---C6          120.3 (5)
  O4---Pr1---O1W            69.36 (14)    C3---C2---C1          119.0 (5)
  O7^i^---Pr1---O1W         139.13 (15)   C6---C2---C1          120.6 (5)
  O5^ii^---Pr1---O1W        79.60 (14)    C2---C3---C4          121.5 (6)
  O1^iii^---Pr1---O1W       144.47 (15)   C2---C3---H3          119.2
  O6---Pr1---O1W            77.88 (14)    C4---C3---H3          119.2
  O1---Pr1---O1W            120.06 (14)   C5---C4---C3          118.5 (5)
  O2W---Pr1---O1W           71.70 (15)    C5---C4---H4          120.7
  O3---Pr1---O2^iii^        153.63 (15)   C3---C4---H4          120.7
  O4---Pr1---O2^iii^        67.95 (13)    N1---C5---C4          119.8 (6)
  O7^i^---Pr1---O2^iii^     65.16 (14)    N1---C5---H5          120.1
  O5^ii^---Pr1---O2^iii^    69.19 (14)    C4---C5---H5          120.1
  O1^iii^---Pr1---O2^iii^   49.16 (12)    O3---C6---N1          118.7 (5)
  O6---Pr1---O2^iii^        96.62 (13)    O3---C6---C2          127.0 (5)
  O1---Pr1---O2^iii^        102.91 (12)   N1---C6---C2          114.3 (5)
  O2W---Pr1---O2^iii^       117.69 (14)   O4---C7---O5          127.0 (5)
  O1W---Pr1---O2^iii^       135.00 (14)   O4---C7---C7^ii^      117.4 (6)
  O3---Pr1---C1^iii^        147.53 (14)   O5---C7---C7^ii^      115.7 (6)
  O4---Pr1---C1^iii^        88.65 (14)    O6---C8---O7          127.4 (5)
  O7^i^---Pr1---C1^iii^     70.79 (14)    O6---C8---C8^i^       116.4 (6)
  O5^ii^---Pr1---C1^iii^    65.76 (14)    O7---C8---C8^i^       116.2 (6)
  O1^iii^---Pr1---C1^iii^   24.77 (14)    Pr1---O1W---H1W       103 (4)
  O6---Pr1---C1^iii^        118.47 (14)   Pr1---O1W---H2W       148 (5)
  O1---Pr1---C1^iii^        83.03 (13)    H1W---O1W---H2W       107 (6)
  O2W---Pr1---C1^iii^       96.95 (15)    Pr1---O2W---H3W       116 (5)
  O1W---Pr1---C1^iii^       144.76 (15)   Pr1---O2W---H4W       70 (3)
  O2^iii^---Pr1---C1^iii^   24.54 (14)    H3W---O2W---H4W       108 (4)
  O3---Pr1---H4W            63.2 (7)                            
  ------------------------- ------------- --------------------- -------------

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

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

  -------------------- ---------- ---------- ----------- ---------------
  *D*---H···*A*        *D*---H    H···*A*    *D*···*A*   *D*---H···*A*
  O2W---H4W···O3       0.83 (3)   2.56 (2)   3.306 (6)   149 (4)
  O2W---H3W···O7^iv^   0.84 (5)   1.95 (6)   2.764 (6)   164 (7)
  O2W---H4W···O2W^v^   0.83 (3)   2.37 (2)   2.820 (8)   114 (2)
  O1W---H2W···O2^v^    0.85 (6)   2.49 (4)   3.280 (7)   157 (8)
  O1W---H1W···O3       0.84 (5)   2.34 (6)   2.760 (6)   111 (5)
  O1W---H1W···O6^vi^   0.84 (5)   2.24 (3)   3.002 (6)   151 (6)
  N1---H1···O4^vi^     0.86 (6)   2.12 (4)   2.878 (7)   146 (6)
  -------------------- ---------- ---------- ----------- ---------------

Symmetry codes: (iv) *x*, *y*−1, *z*; (v) −*x*+1, −*y*+1, −*z*+2; (vi) −*x*+1, −*y*+2, −*z*+2. 

###### Hydrogen-bond geometry (Å, °)

  *D*---H⋯*A*               *D*---H    H⋯*A*      *D*⋯*A*     *D*---H⋯*A*
  ------------------------- ---------- ---------- ----------- -------------
  O2*W*---H4*W*⋯O3          0.83 (3)   2.56 (2)   3.306 (6)   149 (4)
  O2*W*---H3*W*⋯O7^i^       0.84 (5)   1.95 (6)   2.764 (6)   164 (7)
  O2*W*---H4*W*⋯O2*W*^ii^   0.83 (3)   2.37 (2)   2.820 (8)   114 (2)
  O1*W*---H2*W*⋯O2^ii^      0.85 (6)   2.49 (4)   3.280 (7)   157 (8)
  O1*W*---H1*W*⋯O3          0.84 (5)   2.34 (6)   2.760 (6)   111 (5)
  O1*W*---H1*W*⋯O6^iii^     0.84 (5)   2.24 (3)   3.002 (6)   151 (6)
  N1---H1⋯O4^iii^           0.86 (6)   2.12 (4)   2.878 (7)   146 (6)

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