An unusual two-dimensional hydrogen-bonding network in bis­(2,9-dimethyl-1,10-phenanthrolin-1-ium) peroxodisulfate dihydrate

The title compound, 2C₁₄H₁₃N₂⁺·S₂O₈²⁻·2H₂O, is a proton­ated amine salt which is formed from two rather uncommon ionic species, namely a peroxodisulfate (pds²⁻) anion, which lies across a crystallographic inversion centre, and a 2,9-di­methyl-1,10-phenanthrolin-1-ium (Hdmph⁺) cation lying in a general position. Each pds²⁻ anion binds to two water mol­ecules through strong water–peroxo O—H...O inter­actions, giving rise to an unprecedented planar network of hydrogen-bonded macrocycles which run parallel to (100). The atoms of the large R₈⁸(30) rings are provided by four water mol­ecules bridging in fully extended form (...H—O—H...) and four pds²⁻ anions alternately acting as long (...O—S—O—O—S—O...) and short (...O—S—O...) bridges. The Hdmph⁺ cations, in turn, bind to these units through hydrogen bonds involving their protonated N atoms. In addition, the crystal structure also contains π–π and aromatic–peroxo C—H...O inter­actions.

S1. Comment

In spite of not being an extensively explored species, the peroxodisulfate anion (S₂O₈^2-) has been shown to be a versatile ligand towards transition metals; the few relevant entries in the Cambridge Structural Database (CSD; Version 5.29, January 2008 update; Allen, 2002) show that its binding mode can be either monodentate, chelating or bridging, but it can also, unbound, behave as a counter-ion. Somewhat curiously, in all the reported cases, the cation is coordinated by an aromatic amine; these are 2,2'-bipyridine (Harvey, Baggio, Garland & Baggio, 2001; Harrison & Hathaway, 1980; Blackman et al., 1991; Díaz de Vivar et al., 2005), 1,10-phenanthroline (Harvey, Baggio, Garland, Burton & Baggio, 2001; Skogareva et al., 2004), 2,2':6',2''-terpyridine (Harvey, Baggio, Garland & Baggio, 2001; Harvey et al., 2004; Díaz de Vivar et al., 2005), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (Harvey et al., 2004), 2,6-bis(2-benzimidazolyl)pyridine (Harvey et al., 2004, 2005) and 2,9-dimethyl-1,10-phenanthroline (Harvey, Baggio, Garland, Burton & Baggio, 2001; revisited by Marsh, 2004).

While exploring some new synthetic routes to the (scarcely reported) 2,9-dimethyl-1,10-phenanthroline (dmph)/peroxodisulfate (pds) complexes, the title pds salt 2C₁₄H₁₃N₂⁺.S₂O₈^2-.2H₂O, (I), was obtained, where the cationic role is fulfilled by a protonated Hdmph⁺ group.

Fig. 1 shows a view of the asymmetric unit of (I); the pds^2- anion lies across a crystallographic inversion centre and compensates the single positive charge introduced by the extra H atom of Hdmph⁺, thus achieving charge balance. As expected, the Hdmph⁺ cation is planar [the mean deviation from the least-squares plane is 0.007 (1) Å, and the maximum deviation is 0.022 (1) Å for the protonated atom N1] and forms a weak intramolecular N1—H1···N2 hydrogen bond (Table 1) defining an S¹₁(5) pattern [for graph-set notation, see Bernstein et al. (1995)]. This is an inherent characteristic of the rigid atomic arrangement in the Hdmph⁺ cation and has already been described elsewhere (Yu et al., 2006).

We shall now discuss in detail some structural peculiarities of the pds^2- and Hdmph⁺ ions in the few structures where they occur, and which are also revealed in the present structure. For the pds^2- anion, it has been shown that, when it appears in an unperturbed, noncoordinated form [for instance, in the K⁺ (Sivertsen & Sorum, 1969) and NH₄⁺ (Naumov et al., 1997) salts], the anion presents a perfectly planar S—O'—O'—S nucleus (O' = O_core) where one of the three terminal O atoms (O") at each side occupies a perfectly trans position relative to the core, thus configuring a six membered O"—S—O'—O'—S—O" planar entity. These latter O atoms are special in that they subtend an O"—S—O' angle that is much smaller than the two remaining O"—S—O' angles. This fact had already been pointed out by Harvey, Baggio, Garland, Burton & Baggio(2001), where it was qualitatively explained in terms of a previous idea put forward by Cruickshank (1961), regarding the availability of 3d orbitals in SO₄ groups to form strong π-bonding molecular orbitals; this explanation was confirmed by ab initio calculations on the expected geometry of the anion.

The geometry of the pds^2- anion in (I) adjusts almost perfectly to these characteristics. In fact, letting O'= O4 and O"= O2,

(1) the core is perfectly planar; in this particular case, for symmetry reasons, S1—O4—O4ⁱ—S1ⁱ = 180° [symmetry code: (i) -x + 2, -y, -z;

(2) O2 is in an almost exactly trans position with respect to the planar core: O2—S—O4—O4ⁱ = -179.56 (12)°;

(3) O2—S1—O4 [96.98 (7)°] is significantly smaller than O3—S1—O4 [106.65 (8)°] and O1—S1—O4 [106.56 (7)°].

Regarding the Hdmph⁺ group, its peculiarity resides in the fact that protonation introduces differences in the environment of the N atoms, breaking their equivalence in the unprotonated species. This can be explained by the fact that the charge around the N atoms in the unprotonated case is distributed, in the form of lone pairs. When protonation occurs, in the corresponding N atom this charge concentrates in the form of an N—H single bond, with the consequent reduction in repulsion between the charge cloud and the C—N bond. The result is an opening of the C—N—C angle as compared with the remaining, unperturbed N atom. Thus, the C1–N1—C12 angle [123.01 (15)°] in (I) is significantly larger than C10—N2—C11 [118.34 (15)°]. Similar differences can be found in other closely related phenanthrolinium structures [Hphen⁺ (phen is 1,10-phenanthroline; Hensen et al., 1998) and Hdmph⁺ (Yu et al., 2006)].

However, the most appealing feature of the structure is the assembly of four different intermolecular interactions which, in addition to the obvious Coulombic forces, can be envisaged as building up the structure in a stepwise fashion, as follows:

(1) The pds^2- anion binds to two symmetry-related water molecules through two strong (O—H)_water···O_peroxo hydrogen bonds (Table 1), giving rise to an unusual two-dimensional network of R₈⁸(30) macrocycles parallel to (100) (Fig. 2). The 30 atoms involved in each centrosymmetric ring are provided by four water molecules bridging in fully extended form (···H—O—H···) and four pds^2- anions, alternately acting as long (···O—S—O—O—S—O···) or short (···O—S—O···) bridges, leading to an elongated loop with approximate maximum and minimum dimensions of 12.5 and 5.4 Å, respectively.

(2) These two-dimensional structures serve as the planar base to which the Hdmph⁺ groups attach via N1—H1···O1W hydrogen bonds (above and below the plane in Fig. 2) leaving the bulky hydrophobic side facing outwards.

(3) The complex two-dimensional structures thus configured stack along [100], as shown in Fig. 3, with interdigitation of aromatic amines to set them at distances from each other typical of graphitic packing; the structure thereby exhibits π–π interactions (Table 2).

(4) Finally, the inter-layer link is complemented by weak C—H···O bonds involving aromatic H atoms and peroxodisulfate O atoms (Table 1, entries 5–7).

It is worth mentioning that some previously reported pds hydrates, where the pds^2- anion is either free or only weakly coordinated, also exhibit interesting hydrogen-bonding motifs, including C²₂(6) or C³₃(8) linear chains (Figs. 4a and 4c), and doubly isolated R³₃(11) or concatenated R⁴₄(12) loops (Figs. 4d and 4b), but none are comparable in complexity to the unprecedented array of R₈⁸(30) rings displayed in the present structure (Fig. 3e).

Related literature

For related literature, see: Allen (2002); Bernstein et al. (1995); Blackman et al. (1991); Cruickshank (1961); Díaz de Vivar, Harvey, Garland, Baggio & Baggio (2005); Harrison & Hathaway (1980); Harvey et al. (2001a, 2001b, 2004, 2005); Hensen et al. (1998); Marsh (2004); Sivertsen & Sorum (1969); Skogareva et al. (2004); Yu et al. (2006); Yu Naumov et al. (1997).

S2. Experimental

The title salt was obtained while trying to synthesize an Mn^II complex, through direct mixing of aqueous solutions of manganese sulfate monohydrate and potassium peroxodisulfate and a methanol solution of 2,9-dimethyl-1,10-phenanthroline (all solutions 0.008 M). The crystalline compound obtained was the result of a complicated process of crystallization and digestion which took about 20 days until finally resulting in the yellow platelet-like crystals studied.

S3. Refinement

H atoms attached to N and O atoms were found in a difference Fourier synthesis and refined with O—H and N—H distances restrained to 0.85 (2) Å, but with free isotropic displacement parameters. H atoms bound to C atoms were placed in geometrically idealized positions and allowed to ride on their parent atoms, with C—H distances of 0.93 or 0.96 Å and U_iso(H) values of 1.2 or 1.5 times U_eq(C).

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures

	Fig. 1. The symmetry-independent part of the structure of (I), shown with fully shaded ellipsoids (drawn at the 50% level) and filled bonds.
	Fig. 2. The packing of (I), viewed down the [100] direction, showing in bold the hydrogen-bonded two-dimensional network involving water molecules and pds^2- ions. The planar aromatic amines appear vertically in projection.
	Fig. 3. The packing of (I), viewed down the [001] direction, at right angles to the view in Fig. 2, showing the way in which the layers interact through interdigitation of the aromatic amines.
	Fig. 4. A schematic representation of the different pds/water hydrogen-bonding motifs found in the literature. References: (a) Díaz de Vivar et al. (2005), (b) Harvey et al. (2004), (c) Harvey, Baggio, Garland, Burton & Baggio (2001), (d) Harvey et al. (2005), (e) this work.

bis(2,9-dimethyl-1,10-phenanthrolin-1-ium) peroxodisulfate dihydrate

Crystal data

2C14H13N2^+·S2O8^2^−·2H2O	F(000) = 676
Mr = 646.68	Dx = 1.518 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 7236 reflections
a = 9.5644 (19) Å	θ = 3.1–26.2°
b = 13.228 (3) Å	µ = 0.26 mm^−1
c = 11.201 (2) Å	T = 170 K
β = 93.39 (3)°	Platelet, yellow
V = 1414.6 (5) Å^3	0.38 × 0.32 × 0.08 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer	3039 independent reflections
Radiation source: sealed tube	2625 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ϕ and ω scans	θmax = 27.9°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −12→11
Tmin = 0.95, Tmax = 0.98	k = −16→16
11488 measured reflections	l = −14→14

Refinement

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0754P)^2 + 0.4898P] where P = (Fo^2 + 2Fc^2)/3
3039 reflections	(Δ/σ)max < 0.001
216 parameters	Δρmax = 0.38 e Å^−3
3 restraints	Δρmin = −0.34 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S1	−0.11320 (4)	0.12301 (3)	0.03169 (3)	0.02413 (16)
O1	−0.09350 (13)	0.11861 (10)	0.15946 (11)	0.0325 (3)
O2	−0.25703 (15)	0.12424 (10)	−0.01295 (12)	0.0394 (4)
O3	−0.02242 (17)	0.19246 (11)	−0.02208 (14)	0.0509 (4)
O4	−0.07440 (11)	0.00980 (9)	−0.01860 (11)	0.0320 (3)
O1W	0.10123 (14)	0.14136 (12)	0.35528 (13)	0.0401 (4)
H1WB	0.048 (2)	0.1420 (18)	0.2926 (14)	0.061 (8)*
H1WA	0.067 (2)	0.1839 (15)	0.4018 (17)	0.058 (7)*
N1	0.38938 (15)	0.11920 (9)	0.37688 (12)	0.0209 (3)
H1	0.301 (3)	0.1196 (15)	0.384 (2)	0.041 (6)*
N2	0.27471 (14)	0.11720 (9)	0.59515 (12)	0.0214 (3)
C1	0.43730 (19)	0.11746 (11)	0.26702 (15)	0.0243 (4)
C2	0.58240 (19)	0.12290 (11)	0.25477 (16)	0.0270 (4)
H2	0.6175	0.1219	0.1791	0.032*
C3	0.67265 (18)	0.12974 (11)	0.35484 (17)	0.0270 (4)
H3	0.7686	0.1340	0.3464	0.032*
C4	0.62078 (16)	0.13032 (11)	0.46946 (15)	0.0228 (4)
C5	0.70971 (17)	0.13567 (12)	0.57705 (16)	0.0270 (4)
H5	0.8063	0.1392	0.5718	0.032*
C6	0.65559 (17)	0.13565 (12)	0.68616 (16)	0.0254 (4)
H6	0.7152	0.1396	0.7547	0.030*
C7	0.50725 (17)	0.12964 (11)	0.69695 (15)	0.0220 (3)
C8	0.44404 (19)	0.12868 (12)	0.80785 (15)	0.0255 (4)
H8	0.4988	0.1325	0.8791	0.031*
C9	0.30137 (19)	0.12214 (11)	0.80922 (15)	0.0253 (4)
H9	0.2588	0.1217	0.8817	0.030*
C10	0.21809 (17)	0.11597 (11)	0.70017 (15)	0.0226 (3)
C11	0.41564 (16)	0.12406 (10)	0.59334 (14)	0.0199 (3)
C12	0.47548 (16)	0.12467 (10)	0.47863 (14)	0.0197 (3)
C13	0.06177 (17)	0.10880 (13)	0.69865 (16)	0.0287 (4)
H13A	0.0216	0.1741	0.6817	0.043*
H13B	0.0345	0.0860	0.7753	0.043*
H13C	0.0290	0.0617	0.6380	0.043*
C14	0.3345 (2)	0.10951 (13)	0.16215 (16)	0.0314 (4)
H14A	0.2709	0.0548	0.1745	0.047*
H14B	0.3834	0.0970	0.0912	0.047*
H14C	0.2829	0.1716	0.1532	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0279 (3)	0.0259 (2)	0.0187 (2)	0.00328 (15)	0.00223 (16)	−0.00168 (13)
O1	0.0275 (6)	0.0511 (8)	0.0188 (6)	0.0049 (5)	0.0007 (5)	−0.0041 (5)
O2	0.0355 (8)	0.0518 (8)	0.0297 (7)	0.0164 (6)	−0.0094 (6)	−0.0109 (5)
O3	0.0689 (10)	0.0348 (8)	0.0517 (9)	−0.0053 (7)	0.0276 (8)	0.0054 (6)
O4	0.0212 (6)	0.0337 (7)	0.0404 (7)	0.0033 (5)	−0.0055 (5)	−0.0120 (5)
O1W	0.0302 (7)	0.0561 (9)	0.0327 (8)	0.0101 (6)	−0.0085 (6)	−0.0157 (6)
N1	0.0217 (7)	0.0203 (6)	0.0208 (7)	0.0000 (5)	0.0021 (5)	−0.0007 (5)
N2	0.0206 (7)	0.0222 (7)	0.0213 (7)	0.0011 (5)	0.0009 (5)	0.0005 (5)
C1	0.0334 (9)	0.0191 (7)	0.0208 (8)	0.0011 (6)	0.0042 (7)	0.0003 (5)
C2	0.0332 (9)	0.0228 (8)	0.0261 (8)	0.0007 (6)	0.0107 (7)	0.0001 (6)
C3	0.0242 (8)	0.0230 (8)	0.0348 (9)	−0.0013 (6)	0.0098 (7)	0.0011 (6)
C4	0.0208 (8)	0.0186 (7)	0.0293 (9)	0.0001 (5)	0.0033 (7)	0.0004 (6)
C5	0.0186 (7)	0.0261 (8)	0.0360 (9)	−0.0015 (6)	0.0002 (7)	0.0007 (6)
C6	0.0222 (8)	0.0237 (8)	0.0296 (9)	−0.0012 (6)	−0.0054 (7)	−0.0004 (6)
C7	0.0236 (8)	0.0185 (7)	0.0235 (8)	0.0004 (6)	−0.0011 (6)	−0.0008 (5)
C8	0.0302 (9)	0.0250 (8)	0.0208 (8)	0.0007 (6)	−0.0029 (7)	−0.0014 (6)
C9	0.0297 (9)	0.0267 (8)	0.0197 (8)	0.0020 (6)	0.0034 (7)	−0.0001 (6)
C10	0.0231 (8)	0.0217 (7)	0.0231 (8)	0.0024 (6)	0.0026 (6)	0.0007 (5)
C11	0.0212 (7)	0.0168 (7)	0.0217 (8)	0.0003 (5)	0.0013 (6)	0.0003 (5)
C12	0.0212 (8)	0.0170 (7)	0.0211 (8)	0.0002 (5)	0.0016 (6)	−0.0002 (5)
C13	0.0221 (8)	0.0390 (9)	0.0253 (8)	0.0029 (7)	0.0048 (6)	0.0027 (7)
C14	0.0379 (10)	0.0352 (9)	0.0212 (8)	0.0018 (7)	0.0015 (7)	−0.0024 (6)

Geometric parameters (Å, º)

S1—O3	1.4222 (15)	C4—C5	1.435 (2)
S1—O1	1.4335 (13)	C5—C6	1.355 (3)
S1—O2	1.4357 (15)	C5—H5	0.9300
S1—O4	1.6501 (12)	C6—C7	1.433 (2)
O4—O4^i	1.482 (2)	C6—H6	0.9300
O1W—H1WB	0.84 (2)	C7—C8	1.413 (2)
O1W—H1WA	0.85 (2)	C7—C11	1.414 (2)
N1—C1	1.338 (2)	C8—C9	1.368 (2)
N1—C12	1.368 (2)	C8—H8	0.9300
N1—H1	0.85 (2)	C9—C10	1.420 (2)
N2—C10	1.324 (2)	C9—H9	0.9300
N2—C11	1.352 (2)	C10—C13	1.497 (2)
C1—C2	1.404 (3)	C11—C12	1.437 (2)
C1—C14	1.491 (3)	C13—H13A	0.9600
C2—C3	1.377 (3)	C13—H13B	0.9600
C2—H2	0.9300	C13—H13C	0.9600
C3—C4	1.403 (2)	C14—H14A	0.9600
C3—H3	0.9300	C14—H14B	0.9600
C4—C12	1.402 (2)	C14—H14C	0.9600
O3—S1—O1	113.67 (9)	C8—C7—C11	116.38 (15)
O3—S1—O2	116.21 (10)	C8—C7—C6	123.48 (16)
O1—S1—O2	114.51 (8)	C11—C7—C6	120.14 (15)
O3—S1—O4	106.65 (8)	C9—C8—C7	119.28 (16)
O1—S1—O4	106.56 (7)	C9—C8—H8	120.4
O2—S1—O4	96.98 (7)	C7—C8—H8	120.4
O4^i—O4—S1	107.12 (11)	C8—C9—C10	120.19 (16)
H1WB—O1W—H1WA	105.5 (18)	C8—C9—H9	119.9
C1—N1—C12	123.01 (15)	C10—C9—H9	119.9
C1—N1—H1	119.0 (16)	N2—C10—C9	121.69 (16)
C12—N1—H1	118.0 (16)	N2—C10—C13	116.83 (15)
C10—N2—C11	118.34 (15)	C9—C10—C13	121.48 (15)
N1—C1—C2	118.88 (16)	N2—C11—C7	124.12 (15)
N1—C1—C14	118.67 (16)	N2—C11—C12	117.64 (14)
C2—C1—C14	122.45 (16)	C7—C11—C12	118.24 (15)
C3—C2—C1	119.97 (16)	N1—C12—C4	119.50 (15)
C3—C2—H2	120.0	N1—C12—C11	119.51 (14)
C1—C2—H2	120.0	C4—C12—C11	120.99 (15)
C2—C3—C4	120.44 (16)	C10—C13—H13A	109.5
C2—C3—H3	119.8	C10—C13—H13B	109.5
C4—C3—H3	119.8	H13A—C13—H13B	109.5
C12—C4—C3	118.19 (15)	C10—C13—H13C	109.5
C12—C4—C5	118.82 (15)	H13A—C13—H13C	109.5
C3—C4—C5	122.98 (15)	H13B—C13—H13C	109.5
C6—C5—C4	121.22 (16)	C1—C14—H14A	109.5
C6—C5—H5	119.4	C1—C14—H14B	109.5
C4—C5—H5	119.4	H14A—C14—H14B	109.5
C5—C6—C7	120.59 (16)	C1—C14—H14C	109.5
C5—C6—H6	119.7	H14A—C14—H14C	109.5
C7—C6—H6	119.7	H14B—C14—H14C	109.5
O3—S1—O4—O4^i	60.38 (15)	C11—N2—C10—C13	179.72 (13)
O1—S1—O4—O4^i	−61.37 (14)	C8—C9—C10—N2	−0.6 (2)
O2—S1—O4—O4^i	−179.56 (12)	C8—C9—C10—C13	−179.96 (14)
C12—N1—C1—C2	−0.9 (2)	C10—N2—C11—C7	0.3 (2)
C12—N1—C1—C14	178.90 (14)	C10—N2—C11—C12	179.62 (13)
N1—C1—C2—C3	0.1 (2)	C8—C7—C11—N2	−0.6 (2)
C14—C1—C2—C3	−179.73 (14)	C6—C7—C11—N2	179.31 (13)
C1—C2—C3—C4	0.6 (2)	C8—C7—C11—C12	−179.91 (13)
C2—C3—C4—C12	−0.6 (2)	C6—C7—C11—C12	0.0 (2)
C2—C3—C4—C5	178.98 (14)	C1—N1—C12—C4	1.0 (2)
C12—C4—C5—C6	−0.2 (2)	C1—N1—C12—C11	−178.71 (13)
C3—C4—C5—C6	−179.73 (15)	C3—C4—C12—N1	−0.2 (2)
C4—C5—C6—C7	0.4 (2)	C5—C4—C12—N1	−179.79 (13)
C5—C6—C7—C8	179.63 (15)	C3—C4—C12—C11	179.47 (13)
C5—C6—C7—C11	−0.3 (2)	C5—C4—C12—C11	−0.1 (2)
C11—C7—C8—C9	0.3 (2)	N2—C11—C12—N1	0.5 (2)
C6—C7—C8—C9	−179.60 (13)	C7—C11—C12—N1	179.90 (12)
C7—C8—C9—C10	0.3 (2)	N2—C11—C12—C4	−179.19 (12)
C11—N2—C10—C9	0.3 (2)	C7—C11—C12—C4	0.2 (2)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1W	0.85 (2)	1.94 (2)	2.768 (2)	163 (2)
N1—H1···N2	0.85 (2)	2.39 (2)	2.738 (2)	105 (2)
O1W—H1WB···O1	0.84 (2)	1.98 (2)	2.808 (2)	168 (2)
O1W—H1WA···O3^ii	0.85 (2)	2.05 (2)	2.883 (2)	166 (2)
C2—H2···O2^iii	0.93	2.52	3.449 (2)	173
C3—H3···O1^iii	0.93	2.55	3.224 (2)	130
C8—H8···O2^iv	0.93	2.57	3.395 (2)	148

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