Di­aqua­(sulfato-[kappa]O)[2,4,6-tris(2-pyridyl)-1,3,5-triazine-[kappa]³N¹,N²,N⁶]zinc(II) dihydrate

In the title compound, [Zn(SO₄)(C₁₈H₁₂N₆)(H₂O)₂]·2H₂O, the metal complex is monomeric, with an octahedral Zn^II centre coordinated by the tridentate ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tpt), two aqua mol­ecules and a monodentate sulfate ion. A complex hydrogen-bonding scheme is built up out of the profuse availability of donors and acceptors (O-H...O/N and C-H...O) which, in addition to [pi]-[pi] interactions between tpt groups, define a three-dimensional assembly.

S1. Comment

Sulfate-metal complexes have been extensively studied over the years, and their appeal still appears to be maintained: one third of all structural research on the subject has been performed in the last three years [Cambridge Structural Database (CSD), April 2004 Release; Allen, 2002]. There are good reasons for this appeal: in addition to the important role played by the anion in metal-organic chemistry, in recent times some biology-related ones have been reported, viz. its participation in the biosynthesis of cysteine and other S-containing molecules in biological systems. Another focus of our interest in the present work on Zn-sulfate complexes arises as a result of findings from X-ray analyses that the cation may be present in enzyme systems where the sulfate anion is a substrate (Tamasi & Cini, 2003). Finally, to give examples of some applied investigations in which the anion is involved, it can be mentioned that metal sulfate compounds have been studied in relation to porous-framework materials (Khan et al., 2001), and in the chemistry relating to cisplatin (Reedijk, 1992).

To this broad span of interests it can added, as a bonus, that sulfate complexes having polycyclic aromatic ligands (and, additionally, aqua molecules) in their coordination polyhedra have been shown to be extremely prolific in generating crystal structures with a variety of non-covalent interactions. These may be through conventional hydrogen bonds and/or through medium-range contacts linking aromatic rings, either in a parallel displaced arrangement (hereinafter π–π) or in an edge-to-face (or point-to-face) T-shaped conformation (C—H···π) (Janiak, 2000).

It can be concluded, then, that sulfate complexes very often produce interesting crystal structures. Confirming this assertion, we report here a crystallographic study of the title compound, (I), which is a zinc(II) complex with the tridentate ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tpt). \sch

In (I), the metal complex is monomeric, and a distorted octahedral Zn centre is coordinated by three N donors from the tridentate tpt ligand, two cis-related aqua ligands and an O atom of a monodentate sulfate group (Fig. 1).

Several factors might affect the regular geometry of the coordination polyhedron, e.g. the Jahn-Teller effect typical of a d¹⁰ metal atom, but the main distortion of (I) is certainly due to the steric limitations imposed by the tpt ligand. The bond lengths to the central metal atom are clearly differentiated into two groups, with three shorter ones to an aqua O atom (O1W), a sulfate O atom (O1) and the central tpt N atom (N2), and three longer ones to the second aqua O atom (O2W) and the two outermost N atoms in the organic ligand (N1 and N3). The asymmetry in the Zn—N bond lengths may be attributed to the short covalent radius of Zn^II and to the rather inflexible character of the tpt skeleton, which forces a closer approach of the central N atom. A search of the CSD revealed that 16 compounds in which Zn is complexed to tpt (or some closely related ligand) display a similar effect, with a mean Zn—N_central distance of 2.077 (12) Å, and Zn—N_lateral distances of 2.173 (12) (shorter) and 2.199 (17) Å (longer). These compare with 2.073 (4), 2.193 (4) and 2.271 (4) Å, respectively, in (I). Considering these values, it is evident that the marked asymmetry (ca 6%) of the two lateral bonds for (I) is much larger than the average. This is a rather unusual way of binding for these tridentate ligands. Also, the two aqua ligands present very different coordination lengths (Δ Zn—O_water ca 4%), with that which is trans to the short Zn—N2 bond being shorter. Thus, the N2—Zn—O1W axis is significantly shorter, giving the polyhedron a marked oblate character.

The monodentate sulfate ligand binds through atom O1, with a bond distance on the shorter side of the whole range, but there is no correlation with the corresponding S—O bond distances, the double-bond character being rather delocalized. A peculiar feature of the structure of (I) is the leaning of the sulfate anion towards the tpt group, driving one of its free O atoms to be at an almost colliding distance from one of the coordinated N atoms [O2···N2 2.92 (1) Å]. As a consequence of this repulsion, the N2—Zn—O1 bond angle is larger than any of the remaining three (cis) angles involving atom O1. This binding behaviour is quite unusual: we could not trace in the literature any mono-coordinated sulfate complex (irrespective of cation) in which any of its three free O atoms is less than 3.00 Å from a coordinated N or O atom, unless mediated by hydrogen bonding.

The tpt ligand in (I) presents a planar core determined by the three coordinated heterocycles (mean deviation from the least squares plane 0.06 Å), while the remaining terminal pyridyl group is rotated (out of this plane) by 6.9 (1)°.

The profuse availability of donors and acceptors for hydrogen bonding, as well as of aromatic groups with potential to enter into π–π interactions, gives rise to a very complex system of second-order interactions, defining the packing characteristics of the structure. Monomers connected to each other form double chains (or strips) embracing the symmetry centres at (0,1/2,0) and (1/2,1/2,0), while running along the a axis (Fig. 2). The internal single-chain linkage is achieved through two strong hydrogen bonds which involve the two aqua ligands as donors and atoms O2 and O4 from the sulfate anion as acceptors (Table 2).

The `dimerization' of chains into strips is achieved through the hydrogen bond involving atom O2W as a donor and atom N6 from a neighbouring chain as an acceptor. This chain-to-chain linkage is reinforced by the π–π parallel displacive interaction (Fig. 3) resulting from tpt groups related by the (1/2,1/2,0) symmetry centre and characterized by an interplanar spacing of 3.28 (1) Å, with a distance between centres of 3.60 (1) Å and a slippage angle (Janiak, 2000) of 24.4°. The broad `strips' thus generated, which are the real structural units in (I), connect with each other through hydrogen bonds involving the remaining water molecules O3W and O4W. Through these bonds evolving around the line containing the symmetry centres at (0,0,1/2) and (1/2,0,1/2), the solvate water molecules are attached laterally to the outermost sulfate O atom (O3), serving as strip connectors to define some sort of two-dimensional structures parallel to the (011) plane. Weaker C—H···O interactions, mainly those involving aromatic H atoms, connect these structures with each other into the final three-dimensional assembly.

S2. Experimental

The title compound was obtained by direct mixing of equimolar (0.025 M) aqueous ZnSO₄·7H₂O and methanolic 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tpt) solutions. After a few days, some crystalline material precipitated, but it was found to be unsuitable for X-ray diffraction. This material was therefore dissolved in water and heated at 378 K for 2 h in a pressurized reactor. Slow evaporation of this solution resulted in the formation of some colourless prismatic crystals of (I), which were suitable for X-ray analysis.

S3. Refinement

H atoms attached to C atomswere included in their calculated positions, with C—H distances of 0.93 Å, and allowed to ride, with U_iso(H) = 1.2U_eq(C). Please check added text. The water H atoms were located from difference Fourier syntheses and refined with restrained O—H and H···H distances of 0.82 (1) and 1.30 (2) Å, respectively.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: SHELXTL/PC (Sheldrick, 1994); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL/PC; software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. A packing view of (I) down the [011] direction, showing a schematic representation of the two-dimensional array. The way in which strips build up, as well as their interaction mediated by solvate water molecules, is indicated by dashed lines.
	Fig. 3. The overlap of two neighbouring tpt groups related by the centre of symmetry at (1/2,1/2,0), leading to a π–π interaction of the parallel displacive type.

Diaqua(sulfato-κO)[2,4,6-tris(2-pyridyl)-1,3,5-triazine- κ³N¹,N²,N⁶]zinc(II) dihydrate

Crystal data

[Zn(SO4)(C18H12N6)(H2O)2]·2H2O	Z = 2
Mr = 545.83	F(000) = 560
Triclinic, P1	Dx = 1.700 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.7120 (15) Å	Cell parameters from 25 reflections
b = 11.771 (2) Å	θ = 7.5–12.5°
c = 12.523 (3) Å	µ = 1.31 mm^−1
α = 85.27 (3)°	T = 293 K
β = 75.38 (3)°	Prism, colourless
γ = 75.82 (3)°	0.32 × 0.12 × 0.12 mm
V = 1066.2 (4) Å^3

Data collection

Rigaku AFC-6S diffractometer	2117 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.076
Graphite monochromator	θmax = 27.1°, θmin = 1.7°
ω/2θ scans	h = −9→9
Absorption correction: ψ scan (North et al., 1968)	k = −14→15
Tmin = 0.78, Tmax = 0.85	l = 0→15
5725 measured reflections	3 standard reflections every 150 reflections
4670 independent reflections	intensity decay: <2%

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0697P)^2] where P = (Fo^2 + 2Fc^2)/3
4670 reflections	(Δ/σ)max = 0.014
336 parameters	Δρmax = 0.90 e Å^−3
18 restraints	Δρmin = −1.00 e Å^−3

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

	x	y	z	Uiso*/Ueq
Zn	0.43870 (11)	0.25352 (6)	0.22993 (6)	0.0333 (2)
S	0.8222 (2)	0.18460 (11)	0.31375 (12)	0.0329 (4)
O1	0.6709 (5)	0.1558 (3)	0.2765 (3)	0.0372 (10)
O2	0.8625 (6)	0.2949 (3)	0.2610 (3)	0.0421 (11)
O3	0.7713 (7)	0.1986 (4)	0.4363 (3)	0.0555 (13)
O4	0.9891 (6)	0.0891 (3)	0.2813 (3)	0.0470 (11)
N1	0.5972 (6)	0.2460 (4)	0.0502 (4)	0.0330 (12)
N2	0.5250 (6)	0.4088 (3)	0.1935 (3)	0.0224 (10)
N3	0.3277 (6)	0.3528 (3)	0.3827 (4)	0.0315 (12)
N4	0.7050 (7)	0.5254 (4)	0.0741 (4)	0.0353 (12)
N5	0.5491 (7)	0.5848 (4)	0.2597 (4)	0.0382 (12)
N6	0.8074 (7)	0.7348 (4)	0.0321 (4)	0.0412 (13)
C1	0.6251 (8)	0.1633 (5)	−0.0203 (5)	0.0386 (15)
H1	0.5776	0.0979	0.0046	0.046*
C2	0.7237 (9)	0.1674 (5)	−0.1324 (5)	0.0487 (18)
H2	0.7373	0.1085	−0.1812	0.058*
C3	0.7976 (8)	0.2636 (5)	−0.1647 (5)	0.0438 (17)
H3	0.8664	0.2689	−0.2367	0.053*
C4	0.7726 (9)	0.3511 (5)	−0.0938 (4)	0.0373 (16)
H4	0.8211	0.4165	−0.1168	0.045*
C5	0.6736 (7)	0.3399 (4)	0.0127 (4)	0.0307 (14)
C6	0.6345 (7)	0.4303 (4)	0.0952 (4)	0.0271 (13)
C7	0.6551 (8)	0.6005 (4)	0.1574 (4)	0.0290 (13)
C8	0.4868 (8)	0.4872 (4)	0.2713 (4)	0.0279 (13)
C9	0.3648 (8)	0.4609 (5)	0.3807 (4)	0.0306 (13)
C10	0.3048 (9)	0.5381 (5)	0.4632 (5)	0.0352 (14)
H10	0.3359	0.6103	0.4552	0.042*
C11	0.1922 (8)	0.5042 (6)	0.5624 (5)	0.0446 (16)
H11	0.1445	0.5541	0.6220	0.054*
C12	0.1559 (9)	0.3956 (5)	0.5675 (5)	0.0464 (17)
H12	0.0859	0.3703	0.6329	0.056*
C13	0.2202 (9)	0.3226 (5)	0.4785 (5)	0.0432 (16)
H13	0.1887	0.2506	0.4845	0.052*
C14	0.7199 (8)	0.7090 (4)	0.1370 (5)	0.0381 (16)
C15	0.6871 (8)	0.7848 (5)	0.2226 (5)	0.0408 (16)
H15	0.6269	0.7655	0.2935	0.049*
C16	0.7439 (10)	0.8901 (5)	0.2030 (6)	0.0513 (18)
H16	0.7207	0.9424	0.2594	0.062*
C17	0.8346 (9)	0.9132 (5)	0.0981 (5)	0.0455 (17)
H17	0.8789	0.9810	0.0823	0.055*
C18	0.8604 (9)	0.8363 (5)	0.0158 (6)	0.0483 (17)
H18	0.9181	0.8559	−0.0555	0.058*
O1W	0.3363 (6)	0.1087 (3)	0.2578 (3)	0.0462 (11)
H1WA	0.392 (4)	0.0627 (16)	0.297 (3)	0.025 (16)*
H1WB	0.2288 (16)	0.1266 (12)	0.293 (3)	0.030*
O2W	0.1957 (6)	0.3441 (3)	0.1763 (3)	0.0442 (11)
H2WB	0.213 (3)	0.325 (3)	0.1122 (11)	0.053*
H2WA	0.1127 (17)	0.314 (3)	0.211 (3)	0.053*
O3W	1.0003 (9)	0.1261 (5)	0.5924 (4)	0.0720 (16)
H3WA	0.898 (3)	0.154 (4)	0.581 (3)	0.08 (3)*
H3WB	1.012 (8)	0.0549 (7)	0.593 (4)	0.15 (4)*
O4W	0.3851 (14)	−0.0249 (8)	0.4424 (7)	0.110 (2)
H4WB	0.296 (11)	0.015 (7)	0.485 (9)	0.15 (4)*
H4WA	0.367 (12)	−0.091 (3)	0.450 (8)	0.14 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.0419 (5)	0.0253 (3)	0.0273 (4)	−0.0143 (3)	0.0053 (3)	0.0080 (3)
S	0.0335 (9)	0.0264 (7)	0.0360 (9)	−0.0100 (7)	−0.0036 (7)	0.0103 (6)
O1	0.031 (2)	0.035 (2)	0.039 (2)	−0.0061 (18)	−0.002 (2)	0.0135 (18)
O2	0.048 (3)	0.0307 (19)	0.048 (2)	−0.0271 (19)	0.001 (2)	0.0152 (18)
O3	0.078 (4)	0.063 (3)	0.027 (2)	−0.032 (3)	−0.004 (2)	0.007 (2)
O4	0.035 (3)	0.035 (2)	0.063 (3)	−0.0104 (19)	0.001 (2)	0.016 (2)
N1	0.035 (3)	0.023 (2)	0.033 (3)	−0.003 (2)	0.002 (2)	0.004 (2)
N2	0.024 (3)	0.026 (2)	0.019 (2)	−0.0093 (19)	−0.006 (2)	−0.0010 (18)
N3	0.030 (3)	0.023 (2)	0.037 (3)	−0.014 (2)	0.004 (2)	0.0132 (19)
N4	0.041 (3)	0.025 (2)	0.036 (3)	−0.017 (2)	0.002 (2)	0.012 (2)
N5	0.049 (3)	0.033 (2)	0.028 (3)	−0.014 (2)	0.000 (2)	0.011 (2)
N6	0.035 (3)	0.041 (3)	0.042 (3)	−0.009 (2)	−0.006 (3)	0.023 (2)
C1	0.037 (4)	0.036 (3)	0.042 (4)	−0.017 (3)	−0.003 (3)	0.007 (3)
C2	0.049 (4)	0.041 (3)	0.049 (4)	−0.003 (3)	−0.001 (4)	−0.016 (3)
C3	0.040 (4)	0.054 (4)	0.025 (3)	−0.017 (3)	0.017 (3)	0.007 (3)
C4	0.056 (4)	0.032 (3)	0.023 (3)	−0.021 (3)	0.000 (3)	0.005 (2)
C5	0.024 (3)	0.033 (3)	0.025 (3)	−0.007 (2)	0.011 (3)	0.004 (2)
C6	0.023 (3)	0.024 (2)	0.025 (3)	−0.002 (2)	0.003 (2)	0.017 (2)
C7	0.037 (4)	0.020 (2)	0.031 (3)	−0.009 (2)	−0.010 (3)	0.008 (2)
C8	0.042 (4)	0.023 (3)	0.017 (3)	−0.006 (3)	−0.008 (3)	0.008 (2)
C9	0.033 (4)	0.037 (3)	0.023 (3)	−0.011 (3)	−0.009 (3)	0.011 (2)
C10	0.045 (4)	0.025 (3)	0.029 (3)	−0.005 (3)	0.001 (3)	−0.005 (2)
C11	0.025 (4)	0.059 (4)	0.048 (4)	−0.007 (3)	−0.006 (3)	−0.004 (3)
C12	0.055 (4)	0.052 (3)	0.021 (3)	−0.012 (3)	0.007 (3)	0.012 (3)
C13	0.050 (4)	0.049 (4)	0.030 (3)	−0.020 (3)	−0.007 (3)	0.017 (3)
C14	0.040 (4)	0.025 (3)	0.037 (4)	−0.001 (3)	0.006 (3)	0.001 (3)
C15	0.036 (4)	0.037 (3)	0.049 (4)	−0.020 (3)	0.000 (3)	0.008 (3)
C16	0.068 (5)	0.031 (3)	0.059 (5)	−0.023 (3)	−0.014 (4)	0.006 (3)
C17	0.059 (5)	0.024 (3)	0.056 (4)	−0.026 (3)	−0.003 (4)	0.008 (3)
C18	0.054 (4)	0.038 (3)	0.055 (3)	−0.028 (3)	−0.006 (3)	0.023 (3)
O1W	0.039 (3)	0.030 (2)	0.064 (3)	−0.005 (2)	−0.010 (2)	0.017 (2)
O2W	0.049 (3)	0.044 (2)	0.038 (3)	−0.025 (2)	0.002 (2)	0.007 (2)
O3W	0.092 (5)	0.066 (4)	0.070 (4)	−0.044 (3)	−0.029 (3)	0.039 (3)
O4W	0.185 (8)	0.101 (5)	0.079 (5)	−0.095 (6)	−0.054 (5)	0.062 (4)

Geometric parameters (Å, º)

Zn—O1W	2.019 (4)	C4—H4	0.9300
Zn—O1	2.068 (4)	C5—C6	1.469 (7)
Zn—N2	2.073 (4)	C7—C14	1.463 (7)
Zn—O2W	2.154 (5)	C8—C9	1.510 (7)
Zn—N3	2.193 (4)	C9—C10	1.346 (7)
Zn—N1	2.271 (4)	C10—C11	1.414 (8)
S—O2	1.474 (4)	C10—H10	0.9300
S—O4	1.479 (4)	C11—C12	1.368 (8)
S—O1	1.480 (4)	C11—H11	0.9300
S—O3	1.498 (4)	C12—C13	1.377 (8)
N1—C1	1.311 (7)	C12—H12	0.9300
N1—C5	1.372 (6)	C13—H13	0.9300
N2—C8	1.326 (6)	C14—C15	1.386 (7)
N2—C6	1.349 (6)	C15—C16	1.396 (8)
N3—C13	1.350 (7)	C15—H15	0.9300
N3—C9	1.369 (6)	C16—C17	1.364 (8)
N4—C6	1.340 (6)	C16—H16	0.9300
N4—C7	1.343 (6)	C17—C18	1.372 (8)
N5—C8	1.334 (6)	C17—H17	0.9300
N5—C7	1.360 (7)	C18—H18	0.9300
N6—C18	1.339 (7)	O1W—H1WA	0.82 (2)
N6—C14	1.364 (7)	O1W—H1WB	0.82 (2)
C1—C2	1.422 (8)	O2W—H2WA	0.82 (3)
C1—H1	0.9300	O2W—H2WB	0.82 (3)
C2—C3	1.377 (8)	O3W—H3WA	0.82 (3)
C2—H2	0.9300	O3W—H3WB	0.82 (2)
C3—C4	1.362 (7)	O4W—H4WA	0.82 (3)
C3—H3	0.9300	O4W—H4WB	0.82 (5)
C4—C5	1.373 (7)
O1W—Zn—O1	87.93 (17)	N1—C5—C4	123.2 (5)
O1W—Zn—N2	174.68 (19)	N1—C5—C6	114.2 (4)
O1—Zn—N2	97.22 (16)	C4—C5—C6	122.5 (5)
O1W—Zn—O2W	88.71 (17)	N4—C6—N2	123.2 (5)
O1—Zn—O2W	175.89 (15)	N4—C6—C5	122.1 (5)
N2—Zn—O2W	86.09 (16)	N2—C6—C5	114.7 (4)
O1W—Zn—N3	105.84 (16)	N4—C7—N5	125.7 (5)
O1—Zn—N3	94.99 (16)	N4—C7—C14	117.4 (5)
N2—Zn—N3	75.17 (15)	N5—C7—C14	116.8 (5)
O2W—Zn—N3	88.19 (16)	N2—C8—N5	124.9 (5)
O1W—Zn—N1	105.48 (16)	N2—C8—C9	116.2 (5)
O1—Zn—N1	90.39 (16)	N5—C8—C9	118.9 (4)
N2—Zn—N1	73.25 (15)	C10—C9—N3	126.7 (5)
O2W—Zn—N1	88.23 (17)	C10—C9—C8	121.6 (5)
N3—Zn—N1	148.38 (15)	N3—C9—C8	111.7 (4)
O2—S—O4	108.6 (2)	C9—C10—C11	116.9 (6)
O2—S—O1	110.5 (2)	C9—C10—H10	121.5
O4—S—O1	108.5 (2)	C11—C10—H10	121.5
O2—S—O3	108.3 (2)	C12—C11—C10	117.6 (6)
O4—S—O3	110.2 (3)	C12—C11—H11	121.2
O1—S—O3	110.7 (2)	C10—C11—H11	121.2
S—O1—Zn	134.5 (2)	C11—C12—C13	121.7 (6)
C1—N1—C5	117.0 (5)	C11—C12—H12	119.1
C1—N1—Zn	128.0 (4)	C13—C12—H12	119.1
C5—N1—Zn	115.0 (3)	N3—C13—C12	121.9 (6)
C8—N2—C6	117.2 (4)	N3—C13—H13	119.1
C8—N2—Zn	120.0 (3)	C12—C13—H13	119.1
C6—N2—Zn	122.6 (3)	N6—C14—C15	121.3 (5)
C13—N3—C9	115.1 (5)	N6—C14—C7	118.6 (5)
C13—N3—Zn	128.1 (4)	C15—C14—C7	120.1 (5)
C9—N3—Zn	116.8 (3)	C14—C15—C16	120.3 (6)
C6—N4—C7	115.1 (5)	C14—C15—H15	119.8
C8—N5—C7	113.9 (4)	C16—C15—H15	119.8
C18—N6—C14	117.0 (5)	C17—C16—C15	117.5 (6)
N1—C1—C2	124.0 (5)	C17—C16—H16	121.2
N1—C1—H1	118.0	C15—C16—H16	121.2
C2—C1—H1	118.0	C16—C17—C18	119.8 (5)
C3—C2—C1	116.1 (5)	C16—C17—H17	120.1
C3—C2—H2	122.0	C18—C17—H17	120.1
C1—C2—H2	122.0	N6—C18—C17	123.9 (6)
C4—C3—C2	121.7 (5)	N6—C18—H18	118.0
C4—C3—H3	119.1	C17—C18—H18	118.0
C2—C3—H3	119.1	H1WA—O1W—H1WB	106 (2)
C3—C4—C5	118.0 (5)	H2WB—O2W—H2WA	105 (2)
C3—C4—H4	121.0	H3WA—O3W—H3WB	104 (3)
C5—C4—H4	121.0	H4WB—O4W—H4WA	104 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O4W	0.82 (2)	2.01 (2)	2.741 (8)	148 (3)
O1W—H1WB···O4^i	0.82 (2)	2.04 (2)	2.684 (6)	135 (3)
O2W—H2WA···O2^i	0.82 (3)	1.93 (2)	2.705 (6)	156 (1)
O2W—H2WB···N6^ii	0.82 (3)	2.05 (2)	2.849 (6)	165 (4)
O3W—H3WA···O3	0.82 (3)	2.23 (2)	2.898 (8)	139 (3)
O3W—H3WB···O4^iii	0.82 (2)	2.21 (3)	2.868 (7)	137 (4)
O4W—H4WA···O3^iv	0.82 (3)	2.09 (6)	2.778 (7)	141 (8)
O4W—H4WB···O3W^i	0.82 (5)	2.45 (6)	3.263 (14)	171 (12)
C11—H11···O2^v	0.93	2.38	3.250 (7)	156
C13—H13···O3W^i	0.93	2.41	3.228 (8)	147

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