A zwitterion of 1,5-bis­(2-hydroxy­benzamido)-3-aza­pentane: a two-dimensional hydrogen-bonding network involving dimers

The title compound, 2-{N-[2-(2-hydroxy­benzamido)ethyl­ammonio­ethyl]amino­carbon­yl}phenolate, C₁₈H₂₁N₃O₄, crystallizes in a zwitterionic form as a result of inter­molecular proton transfer and possesses a negatively charged phenolate group and a protonated amino group. The 2-hydroxy­benzamide and 2-(amino­carbonyl)­phenolate moieties attached to the two ends of the C-C-N-C-C backbone adopt a cis conformation in relation to this backbone. All N- and O-bound H atoms are involved in hydrogen-bond formation; the zwitterions are first linked into head-to-tail dimers, which are further organized into a two-dimensional network parallel to the crystallographic bc plane.

S1. Comment

There is considerable interest in complexes that are capable of mimicking the active sites of metalloproteins (Cao et al., 2004; Tolman & Spencer, 2001; Xing & DeRose, 2001). Generally, these model complexes are obtained from bulky multidentate ligands in order to construct an environment similar to that found in the proteins. 1,5-Bis(2-hydroxybenzamido)-3-azapentane, bhap, is a potentially pentadentate coordinating ligand containing N and O donor atoms, and has been synthesized in order to study its coordination behavior with several transition metal ions (e.g. Zn²⁺, Cu²⁺ and Co²⁺, which are most the abundant and important metals in biology; Lipscomb & Sträter, 1996). In previous reports, this compound exhibited different chelating modes in the formation of mononuclear or binuclear complexes with copper(II) (Sureshan & Bhattacharya, 1999) and iron(III) ions (Dash & Rath, 2004; Rath et al., 2005 or 2002). However, to the best of our knowledge, there are no published data related to the crystal structure of either bhap or its complexes mentioned above.

It is commonly accepted that the aliphatic amino group acts as a comparatively strong base, whereas the phenol group, as an acid, can be deprotonated in a polar medium. Recently, it was reported that some 5,5'-derivativates of 3-diethylaminomethyl-2,2'-biphenol exist as zwitterions in the crystalline state (Ng et al., 2002; Bartoszak-Adamska et al., 2000; Brzezinski et al., 1998, 1995). The reason for the formation of the zwitterions, confirmed by experimental and theoretical methods, is that the –CH₂N(C₂H₅)₂ group, as a relatively strong base, causes the deprotonation of the nearby phenol group and thereby builds a short intramolecular hydrogen bond involving a six-membered ring. Other zwitterionic species, such as the salicylideneimine Schiff bases (Mondal et al., 2002; Hazell et al., 1997), were also formed as the result of an intramolecular proton transfer. These results prompted us to look into the structure of the bhap molecule, which also bears both aliphatic amine and phenol groups. Here we present the crystal structure of the title compound, (I), which is the zwitterion of bhap obtained by recrystallization from methanol/water.

The structure of compound (I) (Fig. 1) is composed of a 2-hydroxybenzamido and a 2-aminocarbonylphenolate moieties linked by a protonated 3-azapentandiyl chain. The zwitterionic nature is confirmed by the location and free refinement of the relevant H atoms. The two pendant moieties attached to the terminals of the C—C—N—C—C backbone adopt a cis conformation, as shown by the N1—C8—C9—N2 [65.1?(2)°] and N2—C10—C11—N3 torsion angles [78.6?(2)°]. Similar to the previously studied 5,5'-derivativates of 3-diethylaminomethyl-2,2'-biphenol, (I) exists as a zwitterion, with an H atom from one phenol hydroxy group having been transferred to the 3-azapentandiyl N atom. The C8—C9—N2—C10—C11 backbone does not adopt a normal anti staggered conformation as some polymethylene carbon chains do (Wang et al., 2004, 2005); the C10—N2—C9—C8 and C9—N2—C10—C11torsion angles are −176.63?(14) and 86.81?(19)°, and atom C11 deviates from the C10/N2/C9/C8 plane by 1.4242?(9) Å. The protonated N2 atom exhibits tetrahedral sp³ hybridization, whereas the two amide N atoms display planar sp² hybridization. As can be see from Table 1, the N1—C8 and N3—C11 bond distances are shorter than the N2—C9 and N2—C10 bonds as a result of the p-π conjugation. The planarity of the benzamido group is well documented (Halfpenny & Small, 1980; Palmer et al., 1995). In our case, the 2-hydroxybenzamido moiety is also planar, with atoms O2 and N1 deviating 0.2131?(6) and −0.2611?(6) Å from the plane defined by C1–C7/O1. The 2-aminocarbonylphenolate moiety is also planar, with a mean derivation of 0.0267?(5) Å. The two phenyl rings subtend a dihedral angle of 73.4?(6)°. The O1—C1—C6 [121.7?(2)°] and O4—C18—C13 [122.92 ?(15)°] angles are slightly larger than the ideal angle of 120° for sp² hybridization. The bond lengths in the two phenyl groups show significant differences at the O substitution sites. The negative charge of atom O4 is partly transferred to the benzene ring, lengthening the C13—C18 and C18—C17 bonds to 1.414 (3) and 1.409 (3) Å, respectively. The extensive delocalization of the negative charge also causes C18—O4 [1.320 (2) Å] to be slightly shorter than C1—O1 [1.359 (3) Å].

All H atoms bonded to O or N atoms are involved in hydrogen bonds. Within the intramolecular hydrogen-bonding system (Fig. 1 and Table 2), atom O2 atom acts as a double (bifurcated) hydrogen-bond acceptor towards the N2⁺/H2B group and the hydroxy O1/H1 group, forming seven- and six-membered rings, respectively. The former hydrogen bond is comparatively weak because it forms the longer branch of an asymmetric three-centre system (see below). Whereas atom O2 lies in a position close to the hydroxy group, carbonyl atom O3 of the 2-aminocarbonylphenolate moiety is located opposite to the negatively charged O4 atom, with C1—C6—C7—O2 and O3—C12—C13—C18 torsion angles of 12.4 (3) and −175.45 (16)°, respectively. Such an arrangement allows carbonyl atom O3, like atom O2, to act as a hydrogen-bond acceptor towards the same N2⁺/H2B H atom, thus forming a three-centre hydrogen-bond system and a second seven-membered ring. The final intramolecular hydrogen bond involves the phenolate O4⁻ atom, which acts as acceptor towards the N3/H3 group, forming a six-membered ring.

The crystal packing is characterized by two intermolecular hydrogen bonds, which lead to a supramolecular network pattern. As shown in Fig. 2, the zwitterions are dimerized head-to-tail through three pairs of N1—H1A···O4, C5—H5···O4 and C11—H11B···O3 hydrogen-bond interactions. These centrosymmetric dimers are joined by the N2⁺—H2A···O4 interactions into a two-dimensional network parallel to the crystallographic bc plane.

S2. Experimental

The title compound was synthesized according to the method reported by the Sureshan & Bhattacharya (1999). A mixture of methyl salicylate (12.20 g, 0.1 mol) and diethylenetriamine (5.16 g, 0.05 mol) were stirred at 322 K for 12 h. The mass was then crystallized from methanol to afford a colorless solid (m.p. 424–425 K, yield 77%). Crystals of (1) suitable for single-crystal X-ray diffraction were grown by slow evaporation of methanol and water (1:1).

S3. Refinement

All C-bonded H atoms were positioned geometrically and refined as riding [with C—H = 0.93–0.97 Å and U_iso(H) = 1.2U_eq(C)]. The H atoms attached to the hydroxy O atom and to the N atoms were located in a difference map and refined freely with an isotropic model.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. A view of the structure of (I), showing the atom-numbering scheme and displacement ellipsoids at the 30% probability level. The dashed lines represent the intramolecular hydrogen bonds.
	Fig. 2. A packing diagram for (I), showing a two-dimensional supramolecular network involving the dimers. For the sake of clarity, the H atoms not involving in the intermolecular hydrogen bonds are omitted. Atoms marked with a hash sign (#) or an asterisk (*) are at the symmetry positions (−x, 1 − y, −z) and (−x, 1/2 + y, 1/2 − z), respectively.

2-{N-[2-(2-hydroxybenzamido)ethylammonioethyl]aminocarbonyl}phenolate

Crystal data

C18H21N3O4	F(000) = 728
Mr = 343.38	Dx = 1.291 Mg m^−3
Monoclinic, P21/c	Melting point = 423–424 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 10.775 (2) Å	Cell parameters from 2404 reflections
b = 11.668 (2) Å	θ = 2.6–24.3°
c = 14.290 (3) Å	µ = 0.09 mm^−1
β = 100.572 (3)°	T = 294 K
V = 1766.1 (6) Å^3	Block, colorless
Z = 4	0.30 × 0.28 × 0.12 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	3616 independent reflections
Radiation source: fine-focus sealed tube	2100 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
ϕ and ω scans	θmax = 26.4°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −13→13
Tmin = 0.972, Tmax = 0.992	k = −14→13
9668 measured reflections	l = −12→17

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.118	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0557P)^2 + 0.2173P] where P = (Fo^2 + 2Fc^2)/3
3616 reflections	(Δ/σ)max < 0.001
246 parameters	Δρmax = 0.14 e Å^−3
0 restraints	Δρmin = −0.16 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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² 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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.25783 (17)	0.84938 (17)	0.16143 (12)	0.0922 (6)
H1	0.163 (3)	0.859 (2)	0.1689 (19)	0.124 (10)*
O2	0.02119 (13)	0.86542 (12)	0.13935 (10)	0.0640 (4)
O3	0.05542 (12)	0.59885 (11)	0.09812 (10)	0.0569 (4)
O4	0.15778 (11)	0.26527 (11)	0.19007 (8)	0.0492 (3)
N1	−0.10065 (14)	0.82938 (13)	−0.00209 (12)	0.0469 (4)
H1A	−0.1077 (18)	0.8082 (17)	−0.0617 (15)	0.059 (6)*
N2	−0.16556 (14)	0.66339 (13)	0.14445 (11)	0.0397 (4)
H2A	−0.1651 (19)	0.7140 (19)	0.2045 (16)	0.078 (7)*
H2B	−0.082 (2)	0.6550 (16)	0.1283 (13)	0.065 (6)*
N3	−0.01223 (13)	0.42939 (14)	0.14451 (11)	0.0427 (4)
H3	0.0162 (19)	0.3600 (16)	0.1635 (14)	0.061 (6)*
C1	0.2439 (2)	0.85329 (18)	0.06505 (16)	0.0624 (6)
C2	0.3509 (2)	0.8554 (2)	0.0255 (2)	0.0845 (8)
H2	0.4301	0.8542	0.0647	0.101*
C3	0.3415 (3)	0.8591 (2)	−0.0718 (2)	0.0858 (8)
H3A	0.4145	0.8604	−0.0979	0.103*
C4	0.2256 (3)	0.86092 (19)	−0.13090 (18)	0.0728 (7)
H4A	0.2196	0.8634	−0.1966	0.087*
C5	0.1186 (2)	0.85910 (16)	−0.09136 (14)	0.0550 (5)
H5	0.0400	0.8613	−0.1311	0.066*
C6	0.12491 (17)	0.85403 (14)	0.00666 (13)	0.0451 (5)
C7	0.01179 (18)	0.84974 (14)	0.05174 (14)	0.0459 (5)
C8	−0.21575 (17)	0.83078 (16)	0.03666 (14)	0.0528 (5)
H8A	−0.2829	0.8634	−0.0103	0.063*
H8B	−0.2036	0.8803	0.0921	0.063*
C9	−0.25665 (16)	0.71342 (16)	0.06488 (13)	0.0465 (5)
H9A	−0.3386	0.7197	0.0834	0.056*
H9B	−0.2653	0.6626	0.0104	0.056*
C10	−0.19657 (17)	0.54503 (16)	0.17194 (13)	0.0491 (5)
H10A	−0.2876	0.5372	0.1635	0.059*
H10B	−0.1621	0.5335	0.2389	0.059*
C11	−0.14582 (15)	0.45342 (15)	0.11464 (13)	0.0453 (5)
H11A	−0.1928	0.3833	0.1188	0.054*
H11B	−0.1608	0.4767	0.0484	0.054*
C12	0.07869 (15)	0.50023 (16)	0.12951 (11)	0.0389 (4)
C13	0.21071 (15)	0.45751 (15)	0.15188 (11)	0.0399 (4)
C14	0.30507 (17)	0.53558 (18)	0.14225 (14)	0.0570 (5)
H14	0.2827	0.6099	0.1226	0.068*
C15	0.43006 (19)	0.5058 (2)	0.16096 (18)	0.0814 (7)
H15	0.4919	0.5592	0.1541	0.098*
C16	0.4628 (2)	0.3956 (2)	0.19008 (18)	0.0827 (8)
H16	0.5475	0.3747	0.2032	0.099*
C17	0.37225 (19)	0.3160 (2)	0.20002 (15)	0.0662 (6)
H17	0.3969	0.2421	0.2195	0.079*
C18	0.24289 (16)	0.34399 (17)	0.18141 (12)	0.0438 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0663 (11)	0.1393 (17)	0.0633 (11)	−0.0066 (10)	−0.0079 (8)	−0.0143 (10)
O2	0.0648 (9)	0.0805 (11)	0.0468 (9)	−0.0026 (7)	0.0106 (7)	−0.0176 (7)
O3	0.0458 (8)	0.0445 (8)	0.0865 (10)	0.0056 (6)	0.0282 (7)	0.0124 (7)
O4	0.0521 (8)	0.0528 (8)	0.0426 (7)	0.0059 (6)	0.0087 (6)	0.0099 (6)
N1	0.0511 (10)	0.0471 (10)	0.0427 (10)	0.0035 (7)	0.0089 (8)	−0.0001 (8)
N2	0.0341 (8)	0.0437 (9)	0.0423 (9)	0.0020 (7)	0.0095 (7)	−0.0043 (7)
N3	0.0344 (8)	0.0415 (10)	0.0521 (10)	0.0023 (7)	0.0077 (7)	0.0061 (7)
C1	0.0561 (13)	0.0621 (14)	0.0680 (16)	−0.0025 (11)	0.0090 (11)	−0.0066 (11)
C2	0.0543 (15)	0.095 (2)	0.105 (2)	−0.0018 (13)	0.0162 (14)	−0.0007 (16)
C3	0.0698 (18)	0.0760 (18)	0.124 (3)	0.0013 (13)	0.0495 (17)	0.0047 (16)
C4	0.0892 (19)	0.0607 (15)	0.0786 (17)	−0.0010 (12)	0.0420 (15)	0.0115 (12)
C5	0.0661 (14)	0.0449 (12)	0.0564 (13)	−0.0039 (9)	0.0175 (10)	0.0060 (9)
C6	0.0511 (11)	0.0339 (10)	0.0510 (12)	−0.0026 (8)	0.0112 (9)	−0.0018 (8)
C7	0.0588 (13)	0.0326 (10)	0.0455 (12)	0.0014 (9)	0.0077 (9)	−0.0034 (8)
C8	0.0495 (11)	0.0517 (13)	0.0575 (13)	0.0116 (9)	0.0105 (9)	0.0016 (9)
C9	0.0386 (10)	0.0550 (12)	0.0457 (11)	0.0044 (9)	0.0073 (8)	−0.0044 (9)
C10	0.0432 (11)	0.0484 (12)	0.0603 (13)	−0.0016 (9)	0.0212 (9)	0.0034 (9)
C11	0.0348 (10)	0.0423 (11)	0.0584 (12)	−0.0021 (8)	0.0071 (8)	−0.0004 (9)
C12	0.0378 (10)	0.0441 (11)	0.0364 (10)	0.0016 (8)	0.0109 (8)	−0.0029 (8)
C13	0.0347 (9)	0.0498 (11)	0.0349 (10)	0.0005 (8)	0.0058 (7)	−0.0052 (8)
C14	0.0422 (11)	0.0572 (13)	0.0724 (14)	−0.0050 (9)	0.0127 (10)	−0.0080 (11)
C15	0.0379 (13)	0.0871 (19)	0.118 (2)	−0.0088 (12)	0.0108 (13)	−0.0024 (16)
C16	0.0316 (12)	0.115 (2)	0.099 (2)	0.0061 (13)	0.0038 (12)	0.0110 (16)
C17	0.0505 (13)	0.0823 (17)	0.0628 (14)	0.0187 (12)	0.0029 (10)	0.0148 (12)
C18	0.0399 (10)	0.0610 (13)	0.0295 (10)	0.0049 (9)	0.0041 (8)	0.0024 (8)

Geometric parameters (Å, º)

O1—C1	1.359 (3)	C5—H5	0.9300
O1—H1	1.05 (3)	C6—C7	1.480 (3)
O2—C7	1.251 (2)	C8—C9	1.516 (3)
O3—C12	1.244 (2)	C8—H8A	0.9700
O4—C18	1.320 (2)	C8—H8B	0.9700
N1—C7	1.332 (2)	C9—H9A	0.9700
N1—C8	1.448 (2)	C9—H9B	0.9700
N1—H1A	0.88 (2)	C10—C11	1.509 (2)
N2—C9	1.479 (2)	C10—H10A	0.9700
N2—C10	1.490 (2)	C10—H10B	0.9700
N2—H2A	1.04 (2)	C11—H11A	0.9700
N2—H2B	0.97 (2)	C11—H11B	0.9700
N3—C12	1.329 (2)	C12—C13	1.486 (2)
N3—C11	1.452 (2)	C13—C14	1.391 (2)
N3—H3	0.890 (19)	C13—C18	1.414 (3)
C1—C2	1.375 (3)	C14—C15	1.369 (3)
C1—C6	1.395 (3)	C14—H14	0.9300
C2—C3	1.377 (3)	C15—C16	1.378 (3)
C2—H2	0.9300	C15—H15	0.9300
C3—C4	1.373 (3)	C16—C17	1.372 (3)
C3—H3A	0.9300	C16—H16	0.9300
C4—C5	1.374 (3)	C17—C18	1.409 (3)
C4—H4A	0.9300	C17—H17	0.9300
C5—C6	1.391 (3)
C1—O1—H1	99.8 (15)	N2—C9—C8	112.14 (14)
C7—N1—C8	121.96 (17)	N2—C9—H9A	109.2
C7—N1—H1A	121.2 (13)	C8—C9—H9A	109.2
C8—N1—H1A	116.6 (13)	N2—C9—H9B	109.2
C9—N2—C10	114.78 (14)	C8—C9—H9B	109.2
C9—N2—H2A	108.2 (11)	H9A—C9—H9B	107.9
C10—N2—H2A	106.0 (11)	N2—C10—C11	113.10 (15)
C9—N2—H2B	111.7 (11)	N2—C10—H10A	109.0
C10—N2—H2B	103.3 (11)	C11—C10—H10A	109.0
H2A—N2—H2B	112.8 (16)	N2—C10—H10B	109.0
C12—N3—C11	123.58 (16)	C11—C10—H10B	109.0
C12—N3—H3	113.1 (13)	H10A—C10—H10B	107.8
C11—N3—H3	122.2 (13)	N3—C11—C10	114.57 (15)
O1—C1—C2	118.2 (2)	N3—C11—H11A	108.6
O1—C1—C6	121.7 (2)	C10—C11—H11A	108.6
C2—C1—C6	120.1 (2)	N3—C11—H11B	108.6
C1—C2—C3	120.3 (2)	C10—C11—H11B	108.6
C1—C2—H2	119.9	H11A—C11—H11B	107.6
C3—C2—H2	119.9	O3—C12—N3	121.85 (16)
C4—C3—C2	120.8 (2)	O3—C12—C13	120.64 (16)
C4—C3—H3A	119.6	N3—C12—C13	117.50 (17)
C2—C3—H3A	119.6	C14—C13—C18	119.97 (16)
C3—C4—C5	119.0 (2)	C14—C13—C12	116.58 (17)
C3—C4—H4A	120.5	C18—C13—C12	123.45 (16)
C5—C4—H4A	120.5	C15—C14—C13	121.7 (2)
C4—C5—C6	121.7 (2)	C15—C14—H14	119.1
C4—C5—H5	119.2	C13—C14—H14	119.1
C6—C5—H5	119.2	C14—C15—C16	118.9 (2)
C5—C6—C1	118.16 (19)	C14—C15—H15	120.5
C5—C6—C7	123.22 (18)	C16—C15—H15	120.5
C1—C6—C7	118.62 (18)	C17—C16—C15	121.0 (2)
O2—C7—N1	120.14 (18)	C17—C16—H16	119.5
O2—C7—C6	120.58 (17)	C15—C16—H16	119.5
N1—C7—C6	119.28 (17)	C16—C17—C18	121.4 (2)
N1—C8—C9	113.76 (15)	C16—C17—H17	119.3
N1—C8—H8A	108.8	C18—C17—H17	119.3
C9—C8—H8A	108.8	O4—C18—C17	120.11 (18)
N1—C8—H8B	108.8	O4—C18—C13	122.92 (15)
C9—C8—H8B	108.8	C17—C18—C13	116.96 (18)
H8A—C8—H8B	107.7
O1—C1—C2—C3	179.9 (2)	C9—N2—C10—C11	86.81 (19)
C6—C1—C2—C3	0.5 (4)	C12—N3—C11—C10	−72.2 (2)
C1—C2—C3—C4	0.1 (4)	N2—C10—C11—N3	78.6 (2)
C2—C3—C4—C5	0.1 (4)	C11—N3—C12—O3	8.4 (3)
C3—C4—C5—C6	−0.8 (3)	C11—N3—C12—C13	−171.72 (15)
C4—C5—C6—C1	1.4 (3)	O3—C12—C13—C14	4.4 (2)
C4—C5—C6—C7	−178.82 (17)	N3—C12—C13—C14	−175.49 (16)
O1—C1—C6—C5	179.47 (19)	O3—C12—C13—C18	−175.45 (16)
C2—C1—C6—C5	−1.2 (3)	N3—C12—C13—C18	4.7 (2)
O1—C1—C6—C7	−0.4 (3)	C18—C13—C14—C15	−0.2 (3)
C2—C1—C6—C7	178.97 (19)	C12—C13—C14—C15	179.97 (19)
C8—N1—C7—O2	3.5 (3)	C13—C14—C15—C16	0.0 (4)
C8—N1—C7—C6	−176.30 (15)	C14—C15—C16—C17	0.3 (4)
C5—C6—C7—O2	−167.40 (17)	C15—C16—C17—C18	−0.3 (4)
C1—C6—C7—O2	12.4 (3)	C16—C17—C18—O4	178.9 (2)
C5—C6—C7—N1	12.3 (3)	C16—C17—C18—C13	0.1 (3)
C1—C6—C7—N1	−167.84 (17)	C14—C13—C18—O4	−178.60 (16)
C7—N1—C8—C9	−95.3 (2)	C12—C13—C18—O4	1.2 (3)
C10—N2—C9—C8	−176.63 (14)	C14—C13—C18—C17	0.1 (2)
N1—C8—C9—N2	65.1 (2)	C12—C13—C18—C17	179.96 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O4^i	0.88 (2)	2.01 (2)	2.865 (2)	165.7 (18)
N2—H2A···O4^ii	1.04 (2)	1.61 (2)	2.6342 (19)	167.0 (19)
N2—H2B···O3	0.97 (2)	1.75 (2)	2.6933 (19)	163.7 (17)
N2—H2B···O2	0.97 (2)	2.689 (19)	3.109 (2)	106.5 (13)
N3—H3···O4	0.890 (19)	1.87 (2)	2.6475 (19)	145.4 (18)
O1—H1···O2	1.05 (3)	1.51 (3)	2.518 (2)	158 (2)
C5—H5···O4^i	0.93	2.60	3.380 (3)	141
C11—H11B···O3^i	0.97	2.71	3.413 (2)	130

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