Crystal structure of 2-methyl-amino-4-(6-methyl-4-oxo-4H-chromen-3-yl)-3-nitro-pyrano[3,2-c]chromen-5(4H)-one with an unknown solvate.

In the title compound, C23H16N2O7, the mean planes of the two chromene units (r.m.s. deviations = 0.031 and 0.064 Å) are almost normal to one another with a dihedral angle of 85.59 (6)°. The central six-membered pyran ring has a distorted envelope conformation, with the methine C atom at the flap. There is an intra-molecular N-H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(12) ring motif. The dimers are linked by pairs of C-H⋯O hydrogen bonds, enclosing R 2 (2)(6) ring motifs, forming zigzag chains along [001]. The chains are linked by a second pair of C-H⋯O hydrogen bonds, forming slabs parallel to (110). Within the slabs there are C-H⋯π inter-actions present. A region of disordered electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18] following unsuccessful attempts to model it as plausible solvent mol-ecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent mol-ecule(s).

Related literature

For the uses and biological importance of chromenes, see: Ercole et al. (2009 ▸); Geen et al. (1996 ▸); Khan et al. (2010 ▸); Raj et al. (2010 ▸). For the crystal structure of a very similar compound, the 6-chloro-4-oxo-4H-chromen-3-yl derivative, see: Raja et al. (2015 ▸).

Experimental

Crystal data

C23H16N2O7

M = 432.38

Triclinic,

a = 8.0828 (2) Å

b = 11.2035 (3) Å

c = 13.4718 (3) Å

α = 68.580 (1)°

β = 78.877 (1)°

γ = 76.578 (1)°

V = 1096.76 (5) Å3

Z = 2

Mo Kα radiation

μ = 0.10 mm−1

T = 293 K

0.35 × 0.30 × 0.25 mm

Data collection

Bruker SMART APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2008 ▸) T min = 0.966, T max = 0.976

15923 measured reflections

3843 independent reflections

3371 reflections with I > 2σ(I)

R int = 0.015

Refinement

R[F 2 > 2σ(F 2)] = 0.044

wR(F 2) = 0.136

S = 1.04

3843 reflections

295 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.31 e Å−3

Δρmin = −0.25 e Å−3

Data collection: APEX2 (Bruker, 2008 ▸); cell refinement: SAINT (Bruker, 2008 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▸).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015014413/su5172sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015014413/su5172Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989015014413/su5172Isup3.cml

Click here for additional data file.

. DOI: 10.1107/S2056989015014413/su5172fig1.tif

The mol­ecular structure of the title compound, with the atom labelling. The displacement ellipsoids are drawn at 30% probability level.

Click here for additional data file.

a . DOI: 10.1107/S2056989015014413/su5172fig2.tif

The crystal packing of the title compound, viewed along the a axis. The hydrogen bonds are shown as dashed lines (see Table 1 for details).

CCDC reference: 1416085

Additional supporting information: crystallographic information; 3D view; checkCIF report

C23H16N2O7	Z = 2
Mr = 432.38	F(000) = 448
Triclinic, P1	Dx = 1.309 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.0828 (2) Å	Cell parameters from 3371 reflections
b = 11.2035 (3) Å	θ = 2.0–25.0°
c = 13.4718 (3) Å	µ = 0.10 mm−1
α = 68.580 (1)°	T = 293 K
β = 78.877 (1)°	Block, colourless
γ = 76.578 (1)°	0.35 × 0.30 × 0.25 mm
V = 1096.76 (5) Å3

Bruker SMART APEXII CCD diffractometer	3843 independent reflections
Radiation source: fine-focus sealed tube	3371 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
ω and φ scans	θmax = 25.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −9→9
Tmin = 0.966, Tmax = 0.976	k = −12→13
15923 measured reflections	l = −16→16

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.136	w = 1/[σ2(Fo2) + (0.072P)2 + 0.4436P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max < 0.001
3843 reflections	Δρmax = 0.31 e Å−3
295 parameters	Δρmin = −0.25 e Å−3
2 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.008 (2)

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.

	x	y	z	Uiso*/Ueq
C1	0.0694 (2)	0.51857 (18)	0.78511 (14)	0.0377 (4)
C2	0.2157 (2)	0.32971 (17)	0.91324 (14)	0.0359 (4)
C3	0.2648 (2)	0.19541 (18)	0.94755 (16)	0.0443 (5)
H3	0.2412	0.1466	0.9107	0.053*
C4	0.3494 (3)	0.13584 (18)	1.03749 (17)	0.0487 (5)
H4	0.3821	0.0457	1.0618	0.058*
C5	0.3865 (2)	0.20740 (19)	1.09226 (16)	0.0468 (5)
H5	0.4444	0.1653	1.1525	0.056*
C6	0.3380 (2)	0.34104 (18)	1.05799 (14)	0.0391 (4)
H6	0.3627	0.3890	1.0952	0.047*
C7	0.2513 (2)	0.40433 (16)	0.96706 (13)	0.0319 (4)
C8	0.1979 (2)	0.54278 (16)	0.92247 (13)	0.0311 (4)
C9	0.1178 (2)	0.59925 (16)	0.83416 (13)	0.0316 (4)
C10	0.0759 (2)	0.74462 (16)	0.78257 (13)	0.0338 (4)
H10	−0.0427	0.7676	0.7661	0.041*
C11	0.0886 (2)	0.80769 (16)	0.86107 (13)	0.0352 (4)
C12	0.1690 (2)	0.74174 (16)	0.95340 (13)	0.0340 (4)
C13	0.2594 (3)	0.7133 (2)	1.12655 (16)	0.0489 (5)
H13A	0.2585	0.7702	1.1655	0.073*
H13B	0.3750	0.6725	1.1113	0.073*
H13C	0.1920	0.6478	1.1690	0.073*
C14	0.1920 (2)	0.79154 (16)	0.67790 (13)	0.0334 (4)
C15	0.1217 (2)	0.86432 (18)	0.58849 (14)	0.0427 (4)
H15	0.0027	0.8843	0.5940	0.051*
C16	0.3843 (2)	0.87622 (17)	0.47969 (14)	0.0406 (4)
C17	0.4691 (3)	0.9150 (2)	0.37663 (15)	0.0542 (5)
H17	0.4092	0.9665	0.3187	0.065*
C18	0.6426 (3)	0.8761 (2)	0.36163 (16)	0.0561 (6)
H18	0.7000	0.9022	0.2925	0.067*
C19	0.7366 (3)	0.7983 (2)	0.44682 (16)	0.0470 (5)
C20	0.9251 (3)	0.7457 (3)	0.4270 (2)	0.0695 (7)
H20A	0.9637	0.7790	0.3517	0.104*
H20B	0.9430	0.6523	0.4503	0.104*
H20C	0.9884	0.7722	0.4663	0.104*
C21	0.6498 (2)	0.76466 (19)	0.54935 (15)	0.0416 (4)
H21	0.7108	0.7160	0.6074	0.050*
C22	0.4719 (2)	0.80227 (16)	0.56768 (13)	0.0348 (4)
C23	0.3775 (2)	0.75983 (16)	0.67571 (13)	0.0347 (4)
N1	0.0117 (2)	0.93706 (14)	0.83773 (12)	0.0421 (4)
N2	0.1876 (2)	0.78827 (16)	1.02652 (12)	0.0416 (4)
O1	−0.01634 (19)	0.55805 (14)	0.71221 (11)	0.0545 (4)
O2	0.12479 (17)	0.38573 (12)	0.82583 (10)	0.0425 (3)
O3	0.23490 (15)	0.61246 (11)	0.97862 (9)	0.0357 (3)
O4	0.0280 (2)	1.00121 (13)	0.89445 (11)	0.0578 (4)
O5	−0.07417 (19)	0.98938 (13)	0.76059 (11)	0.0537 (4)
O6	0.20862 (17)	0.91158 (14)	0.49046 (10)	0.0510 (4)
O7	0.44855 (17)	0.70098 (15)	0.75704 (10)	0.0510 (4)
H2A	0.138 (3)	0.8717 (17)	1.012 (2)	0.069 (7)*

	U11	U22	U33	U12	U13	U23
C1	0.0364 (9)	0.0412 (10)	0.0370 (9)	−0.0099 (7)	−0.0025 (7)	−0.0139 (8)
C2	0.0314 (9)	0.0366 (9)	0.0385 (9)	−0.0073 (7)	0.0029 (7)	−0.0140 (7)
C3	0.0453 (11)	0.0355 (9)	0.0533 (11)	−0.0100 (8)	0.0039 (9)	−0.0195 (8)
C4	0.0480 (11)	0.0290 (9)	0.0575 (12)	−0.0033 (8)	0.0044 (9)	−0.0086 (8)
C5	0.0436 (11)	0.0407 (10)	0.0436 (10)	−0.0028 (8)	−0.0042 (8)	−0.0033 (8)
C6	0.0373 (9)	0.0385 (9)	0.0375 (9)	−0.0052 (7)	−0.0026 (7)	−0.0099 (7)
C7	0.0273 (8)	0.0333 (8)	0.0329 (8)	−0.0060 (7)	0.0032 (6)	−0.0117 (7)
C8	0.0274 (8)	0.0345 (9)	0.0328 (8)	−0.0061 (7)	0.0019 (6)	−0.0153 (7)
C9	0.0277 (8)	0.0348 (9)	0.0319 (8)	−0.0053 (7)	0.0013 (6)	−0.0131 (7)
C10	0.0310 (8)	0.0343 (9)	0.0333 (9)	−0.0005 (7)	−0.0030 (7)	−0.0117 (7)
C11	0.0366 (9)	0.0311 (9)	0.0346 (9)	−0.0029 (7)	0.0043 (7)	−0.0133 (7)
C12	0.0313 (8)	0.0337 (9)	0.0377 (9)	−0.0074 (7)	0.0064 (7)	−0.0171 (7)
C13	0.0514 (11)	0.0580 (12)	0.0448 (11)	−0.0123 (9)	−0.0050 (9)	−0.0249 (9)
C14	0.0363 (9)	0.0304 (8)	0.0331 (9)	−0.0015 (7)	−0.0036 (7)	−0.0131 (7)
C15	0.0387 (10)	0.0408 (10)	0.0378 (9)	0.0030 (8)	−0.0032 (8)	−0.0074 (8)
C16	0.0452 (10)	0.0344 (9)	0.0367 (9)	−0.0037 (8)	−0.0025 (8)	−0.0086 (7)
C17	0.0632 (13)	0.0530 (12)	0.0317 (10)	−0.0079 (10)	−0.0030 (9)	−0.0001 (9)
C18	0.0653 (14)	0.0600 (13)	0.0352 (10)	−0.0206 (11)	0.0125 (9)	−0.0105 (9)
C19	0.0474 (11)	0.0495 (11)	0.0456 (11)	−0.0181 (9)	0.0077 (8)	−0.0183 (9)
C20	0.0481 (13)	0.0887 (18)	0.0642 (14)	−0.0198 (12)	0.0122 (11)	−0.0219 (13)
C21	0.0404 (10)	0.0474 (10)	0.0377 (9)	−0.0113 (8)	−0.0031 (8)	−0.0139 (8)
C22	0.0404 (9)	0.0332 (9)	0.0316 (9)	−0.0082 (7)	−0.0026 (7)	−0.0117 (7)
C23	0.0378 (9)	0.0378 (9)	0.0302 (8)	−0.0066 (7)	−0.0054 (7)	−0.0129 (7)
N1	0.0500 (9)	0.0327 (8)	0.0379 (8)	−0.0046 (7)	0.0067 (7)	−0.0128 (7)
N2	0.0468 (9)	0.0403 (9)	0.0428 (9)	−0.0071 (7)	−0.0010 (7)	−0.0225 (7)
O1	0.0614 (9)	0.0560 (9)	0.0524 (8)	−0.0106 (7)	−0.0247 (7)	−0.0163 (7)
O2	0.0503 (8)	0.0375 (7)	0.0454 (7)	−0.0108 (6)	−0.0092 (6)	−0.0168 (6)
O3	0.0401 (7)	0.0339 (6)	0.0353 (6)	−0.0029 (5)	−0.0064 (5)	−0.0156 (5)
O4	0.0834 (11)	0.0369 (7)	0.0536 (8)	−0.0042 (7)	0.0007 (7)	−0.0240 (7)
O5	0.0635 (9)	0.0379 (7)	0.0459 (8)	0.0067 (6)	−0.0068 (7)	−0.0075 (6)
O6	0.0469 (8)	0.0526 (8)	0.0336 (7)	0.0055 (6)	−0.0062 (6)	0.0006 (6)
O7	0.0394 (7)	0.0776 (10)	0.0307 (7)	−0.0093 (7)	−0.0087 (5)	−0.0104 (6)

C1—O1	1.201 (2)	C13—H13A	0.9600
C1—O2	1.380 (2)	C13—H13B	0.9600
C1—C9	1.452 (2)	C13—H13C	0.9600
C2—O2	1.379 (2)	C14—C15	1.331 (2)
C2—C3	1.386 (3)	C14—C23	1.455 (2)
C2—C7	1.394 (2)	C15—O6	1.350 (2)
C3—C4	1.378 (3)	C15—H15	0.9300
C3—H3	0.9300	C16—O6	1.377 (2)
C4—C5	1.381 (3)	C16—C17	1.385 (3)
C4—H4	0.9300	C16—C22	1.388 (2)
C5—C6	1.379 (3)	C17—C18	1.367 (3)
C5—H5	0.9300	C17—H17	0.9300
C6—C7	1.400 (2)	C18—C19	1.397 (3)
C6—H6	0.9300	C18—H18	0.9300
C7—C8	1.436 (2)	C19—C21	1.382 (3)
C8—C9	1.339 (2)	C19—C20	1.510 (3)
C8—O3	1.378 (2)	C20—H20A	0.9600
C9—C10	1.503 (2)	C20—H20B	0.9600
C10—C11	1.500 (2)	C20—H20C	0.9600
C10—C14	1.524 (2)	C21—C22	1.401 (3)
C10—H10	0.9800	C21—H21	0.9300
C11—N1	1.382 (2)	C22—C23	1.470 (2)
C11—C12	1.390 (2)	C23—O7	1.227 (2)
C12—N2	1.316 (2)	N1—O5	1.245 (2)
C12—O3	1.360 (2)	N1—O4	1.266 (2)
C13—N2	1.451 (3)	N2—H2A	0.891 (17)
O1—C1—O2	117.20 (16)	H13B—C13—H13C	109.5
O1—C1—C9	125.20 (17)	C15—C14—C23	120.17 (16)
O2—C1—C9	117.59 (15)	C15—C14—C10	119.15 (15)
O2—C2—C3	117.04 (16)	C23—C14—C10	120.67 (14)
O2—C2—C7	121.46 (15)	C14—C15—O6	125.45 (17)
C3—C2—C7	121.46 (17)	C14—C15—H15	117.3
C4—C3—C2	118.48 (18)	O6—C15—H15	117.3
C4—C3—H3	120.8	O6—C16—C17	116.87 (17)
C2—C3—H3	120.8	O6—C16—C22	121.59 (15)
C3—C4—C5	121.26 (17)	C17—C16—C22	121.51 (18)
C3—C4—H4	119.4	C18—C17—C16	118.79 (19)
C5—C4—H4	119.4	C18—C17—H17	120.6
C6—C5—C4	120.26 (18)	C16—C17—H17	120.6
C6—C5—H5	119.9	C17—C18—C19	122.10 (18)
C4—C5—H5	119.9	C17—C18—H18	119.0
C5—C6—C7	119.81 (18)	C19—C18—H18	119.0
C5—C6—H6	120.1	C21—C19—C18	117.97 (19)
C7—C6—H6	120.1	C21—C19—C20	120.9 (2)
C2—C7—C6	118.73 (15)	C18—C19—C20	121.04 (18)
C2—C7—C8	116.42 (15)	C19—C20—H20A	109.5
C6—C7—C8	124.85 (16)	C19—C20—H20B	109.5
C9—C8—O3	122.85 (15)	H20A—C20—H20B	109.5
C9—C8—C7	122.76 (15)	C19—C20—H20C	109.5
O3—C8—C7	114.38 (14)	H20A—C20—H20C	109.5
C8—C9—C1	119.56 (15)	H20B—C20—H20C	109.5
C8—C9—C10	122.40 (15)	C19—C21—C22	121.44 (18)
C1—C9—C10	118.05 (14)	C19—C21—H21	119.3
C11—C10—C9	108.94 (14)	C22—C21—H21	119.3
C11—C10—C14	111.95 (14)	C16—C22—C21	118.12 (16)
C9—C10—C14	111.16 (13)	C16—C22—C23	120.13 (16)
C11—C10—H10	108.2	C21—C22—C23	121.67 (16)
C9—C10—H10	108.2	O7—C23—C14	122.72 (15)
C14—C10—H10	108.2	O7—C23—C22	123.01 (16)
N1—C11—C12	120.88 (15)	C14—C23—C22	114.27 (14)
N1—C11—C10	115.91 (15)	O5—N1—O4	120.53 (15)
C12—C11—C10	123.20 (14)	O5—N1—C11	119.20 (15)
N2—C12—O3	112.04 (15)	O4—N1—C11	120.28 (16)
N2—C12—C11	127.77 (16)	C12—N2—C13	125.94 (16)
O3—C12—C11	120.16 (14)	C12—N2—H2A	112.1 (16)
N2—C13—H13A	109.5	C13—N2—H2A	121.6 (16)
N2—C13—H13B	109.5	C2—O2—C1	121.84 (14)
H13A—C13—H13B	109.5	C12—O3—C8	119.57 (13)
N2—C13—H13C	109.5	C15—O6—C16	117.95 (14)
H13A—C13—H13C	109.5
O2—C2—C3—C4	−177.26 (16)	C10—C14—C15—O6	−179.49 (17)
C7—C2—C3—C4	0.5 (3)	O6—C16—C17—C18	−176.57 (19)
C2—C3—C4—C5	−0.6 (3)	C22—C16—C17—C18	1.8 (3)
C3—C4—C5—C6	0.4 (3)	C16—C17—C18—C19	0.2 (3)
C4—C5—C6—C7	−0.2 (3)	C17—C18—C19—C21	−2.4 (3)
O2—C2—C7—C6	177.36 (14)	C17—C18—C19—C20	173.9 (2)
C3—C2—C7—C6	−0.3 (2)	C18—C19—C21—C22	2.7 (3)
O2—C2—C7—C8	−3.8 (2)	C20—C19—C21—C22	−173.63 (19)
C3—C2—C7—C8	178.49 (15)	O6—C16—C22—C21	176.78 (16)
C5—C6—C7—C2	0.2 (2)	C17—C16—C22—C21	−1.5 (3)
C5—C6—C7—C8	−178.54 (16)	O6—C16—C22—C23	−0.1 (3)
C2—C7—C8—C9	0.1 (2)	C17—C16—C22—C23	−178.40 (18)
C6—C7—C8—C9	178.86 (15)	C19—C21—C22—C16	−0.8 (3)
C2—C7—C8—O3	179.64 (13)	C19—C21—C22—C23	176.05 (17)
C6—C7—C8—O3	−1.6 (2)	C15—C14—C23—O7	174.75 (17)
O3—C8—C9—C1	−174.38 (14)	C10—C14—C23—O7	−3.9 (3)
C7—C8—C9—C1	5.1 (2)	C15—C14—C23—C22	−6.3 (2)
O3—C8—C9—C10	5.9 (2)	C10—C14—C23—C22	175.04 (14)
C7—C8—C9—C10	−174.58 (14)	C16—C22—C23—O7	−175.61 (17)
O1—C1—C9—C8	172.77 (17)	C21—C22—C23—O7	7.6 (3)
O2—C1—C9—C8	−6.7 (2)	C16—C22—C23—C14	5.4 (2)
O1—C1—C9—C10	−7.5 (3)	C21—C22—C23—C14	−171.34 (16)
O2—C1—C9—C10	173.01 (14)	C12—C11—N1—O5	−172.65 (16)
C8—C9—C10—C11	−16.7 (2)	C10—C11—N1—O5	6.1 (2)
C1—C9—C10—C11	163.63 (14)	C12—C11—N1—O4	7.1 (3)
C8—C9—C10—C14	107.12 (17)	C10—C11—N1—O4	−174.13 (15)
C1—C9—C10—C14	−72.56 (19)	O3—C12—N2—C13	−3.6 (2)
C9—C10—C11—N1	−163.56 (14)	C11—C12—N2—C13	174.31 (17)
C14—C10—C11—N1	73.10 (19)	C3—C2—O2—C1	179.89 (15)
C9—C10—C11—C12	15.1 (2)	C7—C2—O2—C1	2.1 (2)
C14—C10—C11—C12	−108.19 (18)	O1—C1—O2—C2	−176.34 (16)
N1—C11—C12—N2	−1.8 (3)	C9—C1—O2—C2	3.1 (2)
C10—C11—C12—N2	179.60 (17)	N2—C12—O3—C8	167.61 (14)
N1—C11—C12—O3	175.96 (14)	C11—C12—O3—C8	−10.4 (2)
C10—C11—C12—O3	−2.7 (2)	C9—C8—O3—C12	9.0 (2)
C11—C10—C14—C15	−111.88 (18)	C7—C8—O3—C12	−170.52 (13)
C9—C10—C14—C15	126.04 (17)	C14—C15—O6—C16	4.0 (3)
C11—C10—C14—C23	66.81 (19)	C17—C16—O6—C15	173.66 (18)
C9—C10—C14—C23	−55.3 (2)	C22—C16—O6—C15	−4.7 (3)
C23—C14—C15—O6	1.8 (3)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O4	0.89 (2)	1.92 (2)	2.623 (2)	135 (2)
N2—H2A···O4i	0.89 (2)	2.28 (2)	2.991 (2)	137 (2)
C15—H15···O6ii	0.93	2.55	3.255 (2)	133
C6—H6···O7iii	0.93	2.51	3.136 (2)	125
C13—H13B···Cg4iii	0.96	2.86	3.059 (3)	142

Table 1

Hydrogen-bond geometry (, )

Cg4 is the centroid of the C2C7 ring.

DHA	DH	HA	D A	DHA
N2H2AO4	0.89(2)	1.92(2)	2.623(2)	135(2)
N2H2AO4i	0.89(2)	2.28(2)	2.991(2)	137(2)
C15H15O6ii	0.93	2.55	3.255(2)	133
C6H6O7iii	0.93	2.51	3.136(2)	125
C13H13B Cg4iii	0.96	2.86	3.059(3)	142

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