Tris(1H-benzimidazol-2-ylmeth­yl)amine methanol tris­­olvate

The structure of the tertiary amine tris­(1H-benzimidazol-2-ylmeth­yl)amine (C₂₄H₂₁N₇, abbreviated ntb) has been previously reported twice as solvates, namely the monohydrate and the aceto­nitrile–methanol–water (1/0.5/1.5) solvate, both with the tripodal conformation formed via multiple hydrogen bonds. Now, we report the tri­methanol adduct, ntb·3CH₃OH, where the amine has the stair conformation featuring one benzimidazole group oriented in the opposite direction from the other two. The asymmetric unit contains one-half amine, completed through the mirror plane m in space group Pmn2₁ to form the ntb mol­ecule, with the H atom for each imidazole moiety equally disordered between both N sites available in the imidazole ring. The asymmetric unit also contains one and a half methanol mol­ecules, one being placed in general position with the hy­droxy H atom disordered over two sites with occupancy ratio 1:1, while the other lies on the m mirror plane, and has thus its hy­droxy H atom disordered by symmetry. As in the previously reported solvates, all imine and amine groups of the ntb mol­ecules and the methanol mol­ecules are involved in N—H⋯O and O—H⋯N hydrogen bonds. In the title compound, however, the involved H atom is systematically a disordered H atom provided by an imidazole group or a methanol mol­ecule.

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Chemical scheme

Structure description

The tertiary amine tris­(1H-benzimidazol-2-ylmeth­yl)amine (abbreviated ntb in the literature) is a mol­ecule that can act as a tetra­dentate ligand through its three imine N atoms and the central amine one, exhibiting thus a versatile and rich coordination chemistry, where the mol­ecule adopts a tripodal coordination mode to the metal (e.g. Nakata et al., 1997; Kwak et al., 1999; Rheingold & Hammes, 2015). In addition, it is a potential hydrogen-bond donor through its three NH amine groups (Su et al., 2000). Similar tripodal behaviour has been found in ntb solvent adducts such as the monohydrate, C₂₄H₂₁N₇·H₂O, and the aceto­nitrile–methanol–water (1/0.5/1.5) solvate, C₂₄H₂₁N₇·C₂H₃N·0.5CH₄O·1.5H₂O. In both cases, ntb forms two N—H⋯O and one O—H⋯N hydrogen bonds with a solvent water mol­ecule (Zhang et al., 2005). In addition, the imine N atoms of the benzimidazolyl arms can be protonated with HNO₃, and the resulting trication then adopts a stair arrangement, where the N atoms of the benzimidazolium fragments inter­act with anions NO₃⁻ through N—H⋯O hydrogen bonds (Cui, 2011).

The present report deals with a new ntb solvate. When this amine is crystallized from methanol solution, the solvate ntb·3CH₃OH is obtained, in space group Pmn2₁. The ntb mol­ecule has one benzimidazolyl arm placed over the mirror m plane (N2/C1⋯C5 group), while the other crystallographically independent arm (N3/N4/C6⋯C13 group) is placed in general position (Fig. 1). As a consequence, instead of the common tripodal mol­ecular geometry (approximate point group: C_3v), the ntb mol­ecule adopts a stair-like conformation (point group: C_s), with one benzimidazole group oriented in the opposite direction from the other two (Fig. 2). The imidazol H atom of the arm bis­ected by the mirror plane, H2, is disordered by symmetry so that the π-bond of this imidazole ring is delocalized over C2 N2 and C2 N2ⁱ bonds [symmetry code: (i) 1 − x, y, z], with a bond length of 1.342 (3) Å. The same kind of delocalization is observed in the other ntb arm, with the imidazolic H atom equally disordered over N3 and N4, and identical bond lengths C7 N3 and C7 N4 of 1.338 (4) and 1.335 (4) Å. In other words, amine and imine sites in ntb are indistinguishable (Fig. 2). As clearly observed in Fig. 1, the methanol molecules of crystallization are recognized by the ntb mol­ecule in a similar way as in the previously described ionic compound ntb·3HNO₃ (Cui, 2011). The methanol mol­ecules are sandwiched between two ntb arms, in order to form three O—H⋯N and three N—H⋯O hydrogen bonds (Table 1), with O⋯N separations spanning a short range, from 2.722 (4) to 2.767 (3) Å. Given that all imidazolic H atoms are disordered, the same holds for hy­droxy H atoms: the first methanol mol­ecule C14—O1 lies in the mirror m plane, with its H atom disordered by symmetry (H1); the second methanol mol­ecule, C15—O2, placed in general position, has its hy­droxy H atom disordered over two sites, H2A and H2B, with half occupancy (Fig. 2). With this arrangement, any physically unreasonable H⋯H contact is avoided, despite all heteroatoms, except N1, being involved in efficient hydrogen bonds. The complete adduct ntb·3CH₃OH thus features three similar ring motifs R₂²(10) sharing the central N1 atom (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N3^i	0.84 (3)	1.95 (4)	2.762 (3)	164 (10)
O2—H2A⋯N2^i	0.86 (3)	1.91 (3)	2.767 (3)	174 (9)
O2—H2B⋯N4	0.86 (3)	1.87 (3)	2.722 (4)	171 (8)
N2—H2⋯O2^i	0.88 (3)	1.92 (3)	2.767 (3)	161 (7)
N3—H3⋯O1	0.88 (3)	1.88 (3)	2.762 (3)	176 (6)
N4—H4⋯O2	0.88 (3)	1.90 (3)	2.722 (4)	156 (3)
Symmetry code: (i) -x+1, y, z.

Figure 1 Mol­ecular structure of the title compound, with displacement ellipsoids for non-H atoms at the 50% probability level. For all disordered H atoms, a single site was retained, in order to emphasize the O—H⋯N and N—H⋯O hydrogen bonds (dotted lines). Non-labelled atoms are generated by the symmetry operation 1 − x, y, z.

Figure 2 View of the title compound rotated by ca 90° in comparison with Fig. 1, showing the stair-like conformation for ntb. All H atoms bonded to heteroatoms are shown. Green H atoms are disordered by symmetry, while purple H atoms are positionally disordered, all having the same half occupancy. The orange line is the trace of the m mirror normal to the a axis.

The supra­molecular structure is further extended by one-dimensional stacks of ntb mol­ecules in the [011] direction. The stair conformation adopted by ntb allows rather close π–π inter­actions between benzimidazole rings along the stacks: mean plane separations for neighbouring rings along a stack are 3.782 (2) and 3.454 (2) Å for the N2/C2–C5 and N3/N4/C7–C13 benzimidazole rings, respectively.

Synthesis and crystallization

The title compound was prepared through the solid-solid condensation reaction of nitrilo­tri­acetic acid (1 g, 5.2 mmol) and o-phenyl­enedi­amine (1.7 g, 15.7 mmol), both reactants contained in a round-bottom flask provided with a septum connected to the outside through a needle, which was maintained at 463–473 K in a sand bath for 1 h. As the heating progressed, a dark-brown solution formed, which solidified when the temperature returned to 298 K. Then, 0.7 g of activated carbon and 20 ml of methanol were added and the mixture refluxed for 2 h. The still hot mixture was filtered in a Büchner funnel, giving an orange filtrate. The product was isolated by successive recrystallizations from methanol in 30% yield, and single crystals grew by slow evaporation at 298 K as colourless needles with a melting point of 543–547 K. IR (KBr): 3391, 3177, 1624, 1535, 1437, 1273, 1119, 737 cm⁻¹.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The crystal emulates a tetra­gonal system (a ≃ b), however, extinctions and structure refinement are consistent with space group Pmn2₁. The imidazole ring in a general position (N3/H3/N4/H4/C7/C8/C13) was restrained to be flat, within a standard deviation of 0.1 ų (Sheldrick, 2015b).

Table 2
Experimental details

Crystal data
Chemical formula	C24H21N7·3CH4O
Mr	503.60
Crystal system, space group	Orthorhombic, Pmn21
Temperature (K)	293
a, b, c (Å)	16.7781 (17), 16.3902 (18), 4.7894 (5)
V (Å^3)	1317.1 (2)
Z	2
Radiation type	Mo Kα
μ (mm^−1)	0.09
Crystal size (mm)	0.77 × 0.17 × 0.10
Data collection
Diffractometer	Agilent Xcalibur, Atlas, Gemini
Absorption correction	Analytical (CrysAlis PRO; Agilent, 2012)
Tmin, Tmax	0.975, 0.995
No. of measured, independent and observed [I > 2σ(I)] reflections	8328, 2938, 1903
Rint	0.047
(sin θ/λ)max (Å^−1)	0.641
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.048, 0.101, 1.03
No. of reflections	2938
No. of parameters	196
No. of restraints	11
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å^−3)	0.14, −0.14
Computer programs: CrysAlis PRO and CrysAlis RED (Agilent, 2012), SHELXT2018/2 (Sheldrick, 2015a), SHELXL2018/3 (Sheldrick, 2015b), OLEX2 (Dolomanov et al., 2009), Mercury (Macrae et al., 2020) and publCIF (Westrip, 2010).

Structural data

Computing details

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis RED (Agilent, 2012); program(s) used to solve structure: SHELXT2018/2 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

Tris(1H-benzimidazol-2-ylmethyl)amine methanol trisolvate

Crystal data

C24H21N7·3CH4O	Dx = 1.270 Mg m^−3
Mr = 503.60	Melting point: 543 K
Orthorhombic, Pmn21	Mo Kα radiation, λ = 0.71073 Å
a = 16.7781 (17) Å	Cell parameters from 1461 reflections
b = 16.3902 (18) Å	θ = 3.8–23.1°
c = 4.7894 (5) Å	µ = 0.09 mm^−1
V = 1317.1 (2) Å^3	T = 293 K
Z = 2	Needle, colourless
F(000) = 536	0.77 × 0.17 × 0.10 mm

Data collection

Agilent Xcalibur, Atlas, Gemini diffractometer	2938 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	1903 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.047
Detector resolution: 10.5564 pixels mm^-1	θmax = 27.1°, θmin = 3.5°
ω scans	h = −21→21
Absorption correction: analytical (CrysAlis PRO; Agilent, 2012)	k = −20→20
Tmin = 0.975, Tmax = 0.995	l = −6→6
8328 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.048	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.101	w = 1/[σ^2(Fo^2) + (0.0376P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2938 reflections	Δρmax = 0.14 e Å^−3
196 parameters	Δρmin = −0.14 e Å^−3
11 restraints	Extinction correction: SHELXL-2018/3 (Sheldrick 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 constraints	Extinction coefficient: 0.011 (2)
Primary atom site location: dual

Special details

Refinement. All C-bonded H atoms were placed in calculated positions and refined as riding atoms, while H atoms bonded to N (H2, H3, H4) and O sites (H1, H2A, H2B) were found in difference maps, and refined with free coordinates and occupancy fixed to 1/2. Corresponding bond lengths were restrained to O—H = 0.85 (2) and N—H = 0.90 (2) Å.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
N1	0.500000	0.7530 (2)	0.4852 (7)	0.0411 (8)
N2	0.43371 (14)	0.56374 (16)	0.6509 (6)	0.0483 (6)
H2	0.3840 (19)	0.578 (4)	0.616 (15)	0.058*	0.5
N3	0.63616 (15)	0.85800 (15)	0.2727 (6)	0.0481 (7)
H3	0.593 (3)	0.886 (3)	0.231 (13)	0.058*	0.5
N4	0.71198 (16)	0.76093 (15)	0.4609 (6)	0.0517 (7)
H4	0.725 (4)	0.7189 (17)	0.565 (8)	0.062*	0.5
C1	0.500000	0.6713 (3)	0.3595 (8)	0.0456 (11)
H1A	0.546531	0.667019	0.240219	0.055*	0.5
H1B	0.453469	0.667019	0.240219	0.055*	0.5
C2	0.500000	0.5995 (3)	0.5526 (8)	0.0441 (11)
C3	0.45864 (17)	0.5001 (2)	0.8202 (7)	0.0467 (8)
C4	0.4157 (2)	0.4429 (2)	0.9728 (8)	0.0620 (9)
H4A	0.360238	0.442753	0.973673	0.074*
C5	0.4586 (2)	0.3865 (2)	1.1222 (9)	0.0674 (10)
H5	0.431646	0.347357	1.226065	0.081*
C6	0.57325 (16)	0.77133 (19)	0.6402 (7)	0.0461 (7)
H6A	0.588978	0.723567	0.746291	0.055*
H6B	0.562722	0.815084	0.771494	0.055*
C7	0.64012 (19)	0.79584 (19)	0.4532 (7)	0.0471 (8)
C8	0.75915 (19)	0.80341 (19)	0.2720 (7)	0.0495 (8)
C9	0.8387 (2)	0.7945 (2)	0.1972 (8)	0.0657 (10)
H9	0.870759	0.754618	0.277911	0.079*
C10	0.8681 (2)	0.8473 (3)	−0.0016 (9)	0.0733 (11)
H10	0.920992	0.842674	−0.057055	0.088*
C11	0.8205 (3)	0.9071 (2)	−0.1211 (9)	0.0712 (11)
H11	0.842493	0.941876	−0.253804	0.085*
C12	0.7416 (2)	0.9164 (2)	−0.0482 (8)	0.0590 (9)
H12	0.709832	0.956296	−0.129831	0.071*
C13	0.71147 (18)	0.86342 (18)	0.1529 (7)	0.0470 (8)
C14	0.500000	1.0001 (4)	−0.0870 (13)	0.0875 (19)
H14A	0.477295	1.049629	−0.015783	0.131*	0.5
H14B	0.468974	0.981180	−0.242542	0.131*	0.5
H14C	0.553731	1.010105	−0.146720	0.131*	0.5
O1	0.500000	0.9415 (3)	0.1199 (10)	0.0815 (11)
H1	0.458 (3)	0.923 (6)	0.19 (2)	0.122*	0.5
C15	0.7479 (2)	0.5979 (2)	0.9575 (8)	0.0747 (11)
H15A	0.768010	0.543691	0.985412	0.112*
H15B	0.702487	0.606585	1.075551	0.112*
H15C	0.788684	0.636824	1.003105	0.112*
O2	0.72533 (13)	0.60776 (15)	0.6755 (6)	0.0605 (7)
H2A	0.676 (2)	0.595 (5)	0.68 (2)	0.091*	0.5
H2B	0.727 (5)	0.657 (2)	0.611 (17)	0.091*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.043 (2)	0.043 (2)	0.0379 (19)	0.000	0.000	−0.0032 (16)
N2	0.0407 (14)	0.0496 (16)	0.0546 (14)	−0.0032 (13)	−0.0037 (15)	0.0040 (14)
N3	0.0464 (16)	0.0483 (16)	0.0496 (15)	−0.0033 (12)	−0.0017 (14)	0.0020 (15)
N4	0.0483 (16)	0.0488 (16)	0.0580 (16)	−0.0015 (14)	−0.0008 (15)	0.0056 (14)
C1	0.046 (2)	0.050 (3)	0.041 (2)	0.000	0.000	−0.004 (2)
C2	0.047 (3)	0.044 (3)	0.041 (3)	0.000	0.000	−0.0046 (19)
C3	0.0454 (17)	0.0455 (18)	0.0492 (16)	−0.0028 (14)	−0.0037 (15)	−0.0035 (15)
C4	0.052 (2)	0.062 (2)	0.072 (2)	−0.0085 (18)	0.001 (2)	0.006 (2)
C5	0.078 (2)	0.053 (2)	0.072 (2)	−0.0092 (17)	0.004 (2)	0.013 (2)
C6	0.0480 (18)	0.0465 (18)	0.0436 (16)	−0.0053 (14)	−0.0038 (17)	−0.0014 (16)
C7	0.050 (2)	0.0470 (19)	0.0445 (17)	−0.0089 (16)	−0.0031 (16)	−0.0069 (17)
C8	0.052 (2)	0.0430 (18)	0.0535 (19)	−0.0070 (16)	−0.0004 (17)	−0.0004 (17)
C9	0.048 (2)	0.067 (2)	0.082 (3)	−0.0003 (18)	0.006 (2)	0.001 (2)
C10	0.056 (2)	0.079 (3)	0.085 (3)	−0.013 (2)	0.017 (2)	−0.003 (2)
C11	0.076 (3)	0.065 (3)	0.073 (3)	−0.016 (2)	0.013 (2)	0.002 (2)
C12	0.065 (2)	0.051 (2)	0.061 (2)	−0.0083 (17)	0.003 (2)	0.0023 (19)
C13	0.0523 (19)	0.0416 (18)	0.0472 (17)	−0.0087 (15)	−0.0005 (18)	−0.0047 (16)
C14	0.088 (4)	0.076 (4)	0.099 (5)	0.000	0.000	0.030 (4)
O1	0.061 (2)	0.085 (3)	0.099 (3)	0.000	0.000	0.039 (2)
C15	0.084 (3)	0.072 (3)	0.068 (3)	−0.006 (2)	−0.009 (2)	0.004 (2)
O2	0.0478 (13)	0.0639 (16)	0.0698 (17)	0.0046 (13)	0.0019 (15)	0.0169 (14)

Geometric parameters (Å, º)

N1—C6^i	1.467 (3)	C6—H6B	0.9700
N1—C6	1.467 (3)	C8—C9	1.390 (4)
N1—C1	1.468 (5)	C8—C13	1.390 (4)
N2—C2	1.342 (3)	C9—C10	1.377 (5)
N2—C3	1.386 (4)	C9—H9	0.9300
N2—H2	0.88 (3)	C10—C11	1.388 (5)
N3—C7	1.338 (4)	C10—H10	0.9300
N3—C13	1.391 (4)	C11—C12	1.378 (5)
N3—H3	0.88 (3)	C11—H11	0.9300
N4—C7	1.335 (4)	C12—C13	1.391 (4)
N4—C8	1.389 (4)	C12—H12	0.9300
N4—H4	0.88 (3)	C14—O1	1.379 (6)
C1—C2	1.496 (6)	C14—H14A	0.9600
C1—H1A	0.9700	C14—H14B	0.9600
C1—H1B	0.9700	C14—H14C	0.9600
C3—C3^i	1.388 (6)	O1—H1	0.84 (3)
C3—C4	1.391 (4)	O1—H1^i	0.84 (3)
C4—C5	1.373 (5)	C15—O2	1.412 (4)
C4—H4A	0.9300	C15—H15A	0.9600
C5—C5^i	1.388 (7)	C15—H15B	0.9600
C5—H5	0.9300	C15—H15C	0.9600
C6—C7	1.491 (4)	O2—H2A	0.86 (3)
C6—H6A	0.9700	O2—H2B	0.86 (3)
C6^i—N1—C6	113.8 (3)	N3—C7—C6	123.8 (3)
C6^i—N1—C1	113.3 (2)	N4—C8—C9	131.5 (3)
C6—N1—C1	113.3 (2)	N4—C8—C13	107.1 (3)
C2—N2—C3	106.5 (3)	C9—C8—C13	121.4 (3)
C2—N2—H2	127 (4)	C10—C9—C8	117.1 (4)
C3—N2—H2	127 (4)	C10—C9—H9	121.5
C7—N3—C13	105.7 (3)	C8—C9—H9	121.5
C7—N3—H3	126 (4)	C9—C10—C11	121.6 (4)
C13—N3—H3	129 (4)	C9—C10—H10	119.2
C7—N4—C8	106.4 (3)	C11—C10—H10	119.2
C7—N4—H4	125 (4)	C12—C11—C10	121.7 (4)
C8—N4—H4	128 (4)	C12—C11—H11	119.1
N1—C1—C2	117.6 (3)	C10—C11—H11	119.1
N1—C1—H1A	107.9	C11—C12—C13	117.1 (3)
C2—C1—H1A	107.9	C11—C12—H12	121.4
N1—C1—H1B	107.9	C13—C12—H12	121.4
C2—C1—H1B	107.9	C8—C13—N3	108.0 (3)
H1A—C1—H1B	107.2	C8—C13—C12	121.1 (3)
N2—C2—N2^i	111.9 (4)	N3—C13—C12	130.9 (3)
N2—C2—C1	124.06 (19)	O1—C14—H14A	109.5
N2^i—C2—C1	124.06 (19)	O1—C14—H14B	109.5
N2—C3—C3^i	107.56 (15)	H14A—C14—H14B	109.5
N2—C3—C4	131.2 (3)	O1—C14—H14C	109.5
C3^i—C3—C4	121.2 (2)	H14A—C14—H14C	109.5
C5—C4—C3	117.1 (3)	H14B—C14—H14C	109.5
C5—C4—H4A	121.5	C14—O1—H1	122 (7)
C3—C4—H4A	121.5	C14—O1—H1^i	122 (7)
C4—C5—C5^i	121.7 (2)	H1—O1—H1^i	116 (10)
C4—C5—H5	119.2	O2—C15—H15A	109.5
C5^i—C5—H5	119.2	O2—C15—H15B	109.5
N1—C6—C7	112.4 (3)	H15A—C15—H15B	109.5
N1—C6—H6A	109.1	O2—C15—H15C	109.5
C7—C6—H6A	109.1	H15A—C15—H15C	109.5
N1—C6—H6B	109.1	H15B—C15—H15C	109.5
C7—C6—H6B	109.1	C15—O2—H2A	102 (7)
H6A—C6—H6B	107.8	C15—O2—H2B	116 (6)
N4—C7—N3	112.9 (3)	H2A—O2—H2B	106 (7)
N4—C7—C6	123.2 (3)
C6^i—N1—C1—C2	−65.7 (2)	N1—C6—C7—N4	−127.8 (3)
C6—N1—C1—C2	65.8 (2)	N1—C6—C7—N3	56.5 (4)
C3—N2—C2—N2^i	−0.9 (5)	C7—N4—C8—C9	179.1 (4)
C3—N2—C2—C1	179.8 (3)	C7—N4—C8—C13	−0.7 (3)
N1—C1—C2—N2	89.6 (4)	N4—C8—C9—C10	179.8 (3)
N1—C1—C2—N2^i	−89.6 (4)	C13—C8—C9—C10	−0.5 (5)
C2—N2—C3—C3^i	0.5 (3)	C8—C9—C10—C11	0.4 (6)
C2—N2—C3—C4	−179.5 (3)	C9—C10—C11—C12	−0.4 (6)
N2—C3—C4—C5	179.9 (4)	C10—C11—C12—C13	0.5 (6)
C3^i—C3—C4—C5	−0.2 (4)	N4—C8—C13—N3	0.9 (3)
C3—C4—C5—C5^i	0.2 (4)	C9—C8—C13—N3	−178.9 (3)
C6^i—N1—C6—C7	−149.0 (2)	N4—C8—C13—C12	−179.6 (3)
C1—N1—C6—C7	79.7 (4)	C9—C8—C13—C12	0.6 (5)
C8—N4—C7—N3	0.2 (4)	C7—N3—C13—C8	−0.8 (3)
C8—N4—C7—C6	−176.0 (3)	C7—N3—C13—C12	179.8 (3)
C13—N3—C7—N4	0.4 (3)	C11—C12—C13—C8	−0.6 (5)
C13—N3—C7—C6	176.5 (3)	C11—C12—C13—N3	178.8 (3)

Symmetry code: (i) −x+1, y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N3^i	0.84 (3)	1.95 (4)	2.762 (3)	164 (10)
O2—H2A···N2^i	0.86 (3)	1.91 (3)	2.767 (3)	174 (9)
O2—H2B···N4	0.86 (3)	1.87 (3)	2.722 (4)	171 (8)
N2—H2···O2^i	0.88 (3)	1.92 (3)	2.767 (3)	161 (7)
N3—H3···O1	0.88 (3)	1.88 (3)	2.762 (3)	176 (6)
N4—H4···O2	0.88 (3)	1.90 (3)	2.722 (4)	156 (3)

Symmetry code: (i) −x+1, y, z.