Isomeric pyrazolo­[3,4-d]­pyrimidine-based mol­ecules: disappearance of dimerization due to interchanged substitutions

In 5-benzyl-1,7-di­methyl-4,5,6,7-tetra­hydro-1H-pyrazolo­[3,4-d]­pyrimidine-4,6-dione, C₁₄H₁₄N₄O₂, which crystallizes in space group P, weak intermolecular C—H...O hydrogen bonds generate dimers. The isomeric compound 1-benzyl-5,7-di­methyl-4,5,6,7-tetra­hydro-1H-pyrazolo­[3,4-d]­pyrimidine-4,6-dione, C₁₄H₁₄N₄O₂, crystallizes in space group P2₁/n, and shows no such dimerization. Instead, it exhibits C—H...π interactions with the phenyl ring. In both structures, the mol­ecules are linked by aromatic π–π-stacking interactions.

S1. Comment

Xanthine (3,7-dihydro-1H-purine-2,6-thione) compounds are well known for their intermolecular stacking (Falk et al., 1998) and C—H···O interactions (Desiraju & Steiner, 1999). Last year, we reported the X-ray structure of 1,3-bis(8-chlorotheophyllin-7-yl)propane, containing the xanthine skeleton, which also shows intermolecular stacking (Maulik et al., 2001). In this communication, we report the X-ray structures of two isomeric compounds, namely 5-benzyl-1,7-dimethyl-4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidine-4,6-dione, (I), and 1-benzyl-5,7-dimethyl-4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidine-4,6-dione, (II). The syntheses of these two compounds have been reported previously (Avasthi et al., 1998) and they are derived from the pyrazolo[3,4-d]pyrimidine ring system; however, structurally they are closer to the xanthine system which is well known for its C—H···O interactions (Desiraju & Steiner, 1999). In xanthine compounds, however, two N atoms flank the CH group, while in compounds (I) and (II), there is only one adjacent N atom.

The conformations of (I) and (II), together with the atom-numbering schemes, are shown in Figs. 1 and 4, respectively. The molecules are isomeric and differ from one another by the interchange of methyl and benzyl groups at positions N1 and C5. The pendent benzyl substituents are out of the planes of the pyrazolo[3,4-d]pyrimidine ring systems [twist angle: 83.2° in (I) and 80.4° in (II)]. The crystal packing of (I) reveals the presence of weak intermolecular C—H···O bonding (Table 1). Interestingly, this hydrogen bonding (C3—H3···O15) leads to the dimerization of the molecules (Fig. 2). The crystal packing (Fig. 3) shows further independent intermolecular stacking between the phenyl rings and the pyrazolo[3,4-d]pyrimidine systems due to π–π interactions. Pairs of phenyl rings (symmetry code: 1 - x, 1 - y, 2 - z) overlap with an interplanar separation of 3.511 (2) Å and a centroid–centroid separation of 3.374 (2) Å in a `parallel displaced' orientation. The face-to-face overlapping of the pyrazolo[3,4-d]pyrimidine ring systems (symmetry code: -x, 2 - y, 1 - z) displays an interplanar separation of 3.276 (2) Å and a centroid–centroid separation of 3.374 (2) Å. Both modes of stacking interactions are common in xanthine compounds (Falk et al., 1998). The crystal packing of (II), on the other hand, shows no such dimerization. Intermolecular stacking, however, is still present (Fig. 5) among pairs of pyrazolo[3,4-d]pyrimidine ring systems [symmetry code: -x, 2 - y, -z; interplanar spacing: 3.303 (3) Å; centroid separation: 3.365 (2) Å], in similar orientations to those found in (I). Thus, the crystal structures of (I) and (II) are stabilized mainly by C—H···O and π–π interactions, and van der Waals forces.

S2. Experimental

Compounds (I) and (II) were synthesized as described in the literature (Avasthii et al.,1998). Diffraction quality crystals of both compounds were obtained by slow evaporation of ethyl acetate/hexane solutions at room temperature.

Computing details

For both compounds, data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL-NT (Bruker, 1997); program(s) used to refine structure: SHELXTL-NT; molecular graphics: SHELXTL-NT; software used to prepare material for publication: SHELXTL-NT.

Figures

	Fig. 1. Displacement ellipsoid plot (30% probability) showing the molecular structure of (I) with the atom-labelling scheme.
	Fig. 2. Crystal-packing diagram showing the dimerization of the molecules of (I) through C—H···O hydrohen bonding (dashed lines).
	Fig. 3. Crystal packing diagram of (I) showing the intermolecular π–π stacking among the phenyl rings and pyrazolo[3,4-d]pirimidine rings in pairs.
	Fig. 4. Displacement ellipsoid plot (30% probability) showing the molecular structure of (II) with the atom-labelling scheme.
	Fig. 5. Crystal-packing diagram of (II) showing the intermolecular π–π stacking between pyrazolo[3,4-d]pirimidine rings.

(I) 5-benzyl-1,7-dimethyl-4,6-dioxo-4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidine

Crystal data

C14H14N4O2	F(000) = 284
Mr = 270.29	Dx = 1.380 Mg m^−3
Triclinic, P1	Melting point: 165 K
a = 7.476 (1) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.923 (1) Å	Cell parameters from 59 reflections
c = 10.155 (1) Å	θ = 5.0–14.9°
α = 76.68 (1)°	µ = 0.10 mm^−1
β = 89.08 (1)°	T = 293 K
γ = 80.66 (1)°	Block, colourless
V = 650.3 (1) Å^3	0.45 × 0.30 × 0.20 mm
Z = 2

Data collection

Bruker P4 diffractometer	Rint = 0.015
Radiation source: fine-focus sealed tube	θmax = 26.0°, θmin = 2.1°
Graphite monochromator	h = −1→9
θ–2θ scans	k = −10→10
3155 measured reflections	l = −12→12
2539 independent reflections	3 standard reflections every 97 reflections
2128 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.134	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0745P)^2 + 0.1361P] where P = (Fo^2 + 2Fc^2)/3
2539 reflections	(Δ/σ)max < 0.001
183 parameters	Δρmax = 0.16 e Å^−3
0 restraints	Δρmin = −0.30 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
N1	0.02330 (18)	0.88518 (15)	0.27577 (13)	0.0451 (3)
N2	0.14767 (19)	0.98266 (16)	0.22909 (15)	0.0500 (4)
C3	0.2439 (2)	0.98326 (18)	0.33610 (17)	0.0458 (4)
H3	0.3378	1.0404	0.3344	0.055*
C3A	0.18683 (19)	0.88677 (17)	0.45331 (16)	0.0394 (3)
C4	0.2426 (2)	0.84822 (18)	0.59221 (17)	0.0420 (4)
N5	0.14501 (17)	0.74149 (15)	0.67411 (13)	0.0412 (3)
C6	0.0018 (2)	0.68083 (18)	0.63141 (16)	0.0424 (4)
N7	−0.05104 (17)	0.72858 (14)	0.49623 (13)	0.0425 (3)
C7A	0.04519 (19)	0.82716 (16)	0.40989 (15)	0.0381 (3)
C8	0.1934 (2)	0.6894 (2)	0.81865 (16)	0.0472 (4)
H8A	0.0833	0.6883	0.8704	0.057*
H8B	0.2597	0.7636	0.8442	0.057*
C9	0.3071 (2)	0.52937 (18)	0.85475 (15)	0.0414 (4)
C10	0.2802 (2)	0.4252 (2)	0.97390 (17)	0.0529 (4)
H10	0.1897	0.4529	1.0318	0.063*
C11	0.3881 (3)	0.2788 (2)	1.0076 (2)	0.0665 (6)
H11	0.3689	0.2092	1.0880	0.080*
C12	0.5219 (3)	0.2363 (2)	0.9239 (2)	0.0631 (5)
H12	0.5924	0.1377	0.9464	0.076*
C13	0.5515 (3)	0.3398 (2)	0.8065 (2)	0.0616 (5)
H13	0.6436	0.3123	0.7498	0.074*
C14	0.4449 (2)	0.4849 (2)	0.77241 (18)	0.0532 (4)
H14	0.4660	0.5543	0.6924	0.064*
O15	0.36170 (17)	0.89873 (15)	0.64121 (13)	0.0601 (4)
C16	−0.0948 (3)	0.8539 (3)	0.1761 (2)	0.0701 (6)
H16A	−0.0809	0.7434	0.1835	0.105*
H16B	−0.0629	0.9046	0.0869	0.105*
H16C	−0.2186	0.8931	0.1922	0.105*
C17	−0.2185 (3)	0.6832 (2)	0.4563 (2)	0.0634 (5)
H17A	−0.3088	0.7746	0.4285	0.095*
H17B	−0.2615	0.6128	0.5318	0.095*
H17C	−0.1947	0.6326	0.3826	0.095*
O18	−0.07452 (17)	0.58907 (15)	0.71081 (13)	0.0605 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0449 (7)	0.0438 (7)	0.0448 (7)	−0.0085 (6)	−0.0043 (6)	−0.0051 (6)
N2	0.0491 (8)	0.0458 (7)	0.0509 (8)	−0.0100 (6)	0.0032 (6)	−0.0011 (6)
C3	0.0401 (8)	0.0409 (8)	0.0549 (9)	−0.0105 (6)	0.0044 (7)	−0.0056 (7)
C3A	0.0327 (7)	0.0367 (7)	0.0485 (8)	−0.0073 (6)	0.0009 (6)	−0.0084 (6)
C4	0.0332 (7)	0.0412 (8)	0.0523 (9)	−0.0081 (6)	−0.0018 (6)	−0.0107 (7)
N5	0.0374 (6)	0.0430 (7)	0.0426 (7)	−0.0088 (5)	−0.0020 (5)	−0.0073 (5)
C6	0.0378 (8)	0.0422 (8)	0.0476 (9)	−0.0108 (6)	0.0027 (6)	−0.0079 (7)
N7	0.0377 (7)	0.0422 (7)	0.0492 (7)	−0.0152 (5)	−0.0030 (6)	−0.0074 (6)
C7A	0.0351 (7)	0.0331 (7)	0.0453 (8)	−0.0042 (6)	0.0000 (6)	−0.0082 (6)
C8	0.0467 (9)	0.0544 (9)	0.0409 (8)	−0.0086 (7)	−0.0003 (7)	−0.0119 (7)
C9	0.0396 (8)	0.0477 (8)	0.0391 (8)	−0.0140 (6)	−0.0034 (6)	−0.0092 (6)
C10	0.0493 (9)	0.0656 (11)	0.0435 (9)	−0.0210 (8)	−0.0018 (7)	−0.0036 (8)
C11	0.0752 (13)	0.0626 (11)	0.0540 (11)	−0.0254 (10)	−0.0164 (10)	0.0129 (9)
C12	0.0678 (12)	0.0474 (10)	0.0698 (12)	−0.0043 (9)	−0.0219 (10)	−0.0065 (9)
C13	0.0598 (11)	0.0586 (11)	0.0635 (11)	0.0016 (9)	−0.0015 (9)	−0.0159 (9)
C14	0.0568 (10)	0.0504 (9)	0.0482 (9)	−0.0062 (8)	0.0055 (8)	−0.0050 (7)
O15	0.0507 (7)	0.0701 (8)	0.0639 (8)	−0.0280 (6)	−0.0115 (6)	−0.0110 (6)
C16	0.0857 (14)	0.0780 (13)	0.0489 (10)	−0.0279 (11)	−0.0174 (10)	−0.0077 (9)
C17	0.0544 (10)	0.0703 (12)	0.0692 (12)	−0.0340 (9)	−0.0109 (9)	−0.0062 (9)
O18	0.0584 (8)	0.0665 (8)	0.0564 (7)	−0.0303 (6)	0.0048 (6)	−0.0002 (6)

Geometric parameters (Å, º)

N1—C7A	1.343 (2)	C8—H8B	0.9700
N1—N2	1.380 (2)	C9—C10	1.380 (2)
N1—C16	1.457 (2)	C9—C14	1.382 (2)
N2—C3	1.314 (2)	C10—C11	1.390 (3)
C3—C3A	1.404 (2)	C10—H10	0.9300
C3—H3	0.9300	C11—C12	1.366 (3)
C3A—C7A	1.380 (2)	C11—H11	0.9300
C3A—C4	1.425 (2)	C12—C13	1.369 (3)
C4—O15	1.2211 (19)	C12—H12	0.9300
C4—N5	1.404 (2)	C13—C14	1.378 (3)
N5—C6	1.392 (2)	C13—H13	0.9300
N5—C8	1.466 (2)	C14—H14	0.9300
C6—O18	1.2161 (19)	C16—H16A	0.9600
C6—N7	1.384 (2)	C16—H16B	0.9600
N7—C7A	1.3747 (19)	C16—H16C	0.9600
N7—C17	1.467 (2)	C17—H17A	0.9600
C8—C9	1.506 (2)	C17—H17B	0.9600
C8—H8A	0.9700	C17—H17C	0.9600
C7A—N1—N2	110.53 (13)	C10—C9—C14	118.21 (16)
C7A—N1—C16	131.66 (15)	C10—C9—C8	120.58 (15)
N2—N1—C16	117.62 (14)	C14—C9—C8	121.18 (14)
C3—N2—N1	105.63 (13)	C9—C10—C11	120.16 (17)
N2—C3—C3A	111.42 (14)	C9—C10—H10	119.9
N2—C3—H3	124.3	C11—C10—H10	119.9
C3A—C3—H3	124.3	C12—C11—C10	120.72 (17)
C7A—C3A—C3	104.76 (14)	C12—C11—H11	119.6
C7A—C3A—C4	121.32 (14)	C10—C11—H11	119.6
C3—C3A—C4	133.90 (14)	C11—C12—C13	119.51 (18)
O15—C4—N5	120.59 (15)	C11—C12—H12	120.2
O15—C4—C3A	126.27 (15)	C13—C12—H12	120.2
N5—C4—C3A	113.14 (13)	C12—C13—C14	120.06 (19)
C6—N5—C4	125.95 (13)	C12—C13—H13	120.0
C6—N5—C8	115.78 (13)	C14—C13—H13	120.0
C4—N5—C8	118.27 (13)	C13—C14—C9	121.32 (17)
O18—C6—N7	121.19 (14)	C13—C14—H14	119.3
O18—C6—N5	120.85 (15)	C9—C14—H14	119.3
N7—C6—N5	117.96 (13)	N1—C16—H16A	109.5
C7A—N7—C6	118.68 (13)	N1—C16—H16B	109.5
C7A—N7—C17	123.55 (14)	H16A—C16—H16B	109.5
C6—N7—C17	117.47 (14)	N1—C16—H16C	109.5
N1—C7A—N7	129.51 (14)	H16A—C16—H16C	109.5
N1—C7A—C3A	107.65 (14)	H16B—C16—H16C	109.5
N7—C7A—C3A	122.83 (14)	N7—C17—H17A	109.5
N5—C8—C9	112.97 (13)	N7—C17—H17B	109.5
N5—C8—H8A	109.0	H17A—C17—H17B	109.5
C9—C8—H8A	109.0	N7—C17—H17C	109.5
N5—C8—H8B	109.0	H17A—C17—H17C	109.5
C9—C8—H8B	109.0	H17B—C17—H17C	109.5
H8A—C8—H8B	107.8
C7A—N1—N2—C3	−0.24 (17)	N2—N1—C7A—C3A	−0.12 (17)
C16—N1—N2—C3	−175.89 (15)	C16—N1—C7A—C3A	174.72 (18)
N1—N2—C3—C3A	0.50 (18)	C6—N7—C7A—N1	177.97 (14)
N2—C3—C3A—C7A	−0.57 (18)	C17—N7—C7A—N1	−8.5 (3)
N2—C3—C3A—C4	−179.27 (16)	C6—N7—C7A—C3A	−3.3 (2)
C7A—C3A—C4—O15	−177.37 (15)	C17—N7—C7A—C3A	170.28 (15)
C3—C3A—C4—O15	1.2 (3)	C3—C3A—C7A—N1	0.40 (16)
C7A—C3A—C4—N5	2.6 (2)	C4—C3A—C7A—N1	179.30 (13)
C3—C3A—C4—N5	−178.90 (16)	C3—C3A—C7A—N7	−178.60 (13)
O15—C4—N5—C6	177.15 (14)	C4—C3A—C7A—N7	0.3 (2)
C3A—C4—N5—C6	−2.8 (2)	C6—N5—C8—C9	79.46 (17)
O15—C4—N5—C8	−1.7 (2)	C4—N5—C8—C9	−101.57 (16)
C3A—C4—N5—C8	178.34 (12)	N5—C8—C9—C10	−141.39 (15)
C4—N5—C6—O18	−179.73 (14)	N5—C8—C9—C14	41.0 (2)
C8—N5—C6—O18	−0.9 (2)	C14—C9—C10—C11	−1.1 (2)
C4—N5—C6—N7	0.1 (2)	C8—C9—C10—C11	−178.77 (15)
C8—N5—C6—N7	178.93 (13)	C9—C10—C11—C12	0.2 (3)
O18—C6—N7—C7A	−177.18 (14)	C10—C11—C12—C13	0.9 (3)
N5—C6—N7—C7A	3.0 (2)	C11—C12—C13—C14	−1.0 (3)
O18—C6—N7—C17	8.9 (2)	C12—C13—C14—C9	0.1 (3)
N5—C6—N7—C17	−170.91 (14)	C10—C9—C14—C13	0.9 (3)
N2—N1—C7A—N7	178.80 (14)	C8—C9—C14—C13	178.64 (16)
C16—N1—C7A—N7	−6.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O15^i	0.93	2.42	3.317 (2)	161

Symmetry code: (i) −x+1, −y+2, −z+1.

(II) 1-benzyl-5,7-dimethyl-4-dioxo-4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidine

Crystal data

C14H14N4O2	Dx = 1.356 Mg m^−3
Mr = 270.29	Melting point: 142 K
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 12.468 (1) Å	Cell parameters from 43 reflections
b = 7.449 (1) Å	θ = 5.1–12.5°
c = 15.076 (2) Å	µ = 0.10 mm^−1
β = 108.94 (1)°	T = 293 K
V = 1324.4 (3) Å^3	Block, colourless
Z = 4	0.38 × 0.28 × 0.20 mm
F(000) = 568

Data collection

Bruker P4 diffractometer	Rint = 0.089
Radiation source: fine-focus sealed tube	θmax = 27.0°, θmin = 1.9°
Graphite monochromator	h = −1→15
θ–2θ scans	k = −1→9
3782 measured reflections	l = −19→18
2885 independent reflections	3 standard reflections every 97 reflections
1504 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.159	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0653P)^2 + 0.0892P] where P = (Fo^2 + 2Fc^2)/3
2885 reflections	(Δ/σ)max < 0.001
183 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.22 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
N1	0.20916 (16)	0.9282 (3)	0.00658 (13)	0.0581 (6)
N2	0.1691 (2)	0.9101 (3)	−0.08991 (14)	0.0661 (6)
C3	0.0697 (2)	0.8320 (4)	−0.10896 (17)	0.0633 (7)
H3	0.0223	0.8059	−0.1693	0.076*
C3A	0.0439 (2)	0.7932 (3)	−0.02766 (15)	0.0511 (6)
C4	−0.0514 (2)	0.7118 (3)	−0.00995 (17)	0.0560 (6)
N5	−0.03889 (15)	0.7023 (3)	0.08547 (13)	0.0539 (5)
C6	0.0535 (2)	0.7604 (3)	0.15857 (16)	0.0525 (6)
N7	0.14192 (15)	0.8447 (3)	0.13688 (12)	0.0513 (5)
C7A	0.13447 (19)	0.8556 (3)	0.04462 (15)	0.0493 (6)
C8	0.3228 (2)	0.9998 (4)	0.04671 (19)	0.0663 (7)
H8A	0.3236	1.0818	0.0969	0.080*
H8B	0.3411	1.0686	−0.0011	0.080*
C9	0.4136 (2)	0.8603 (4)	0.08494 (17)	0.0580 (6)
C10	0.3924 (2)	0.6790 (4)	0.0765 (2)	0.0835 (9)
H10	0.3190	0.6383	0.0463	0.100*
C11	0.4787 (3)	0.5570 (5)	0.1123 (3)	0.1017 (11)
H11	0.4634	0.4345	0.1069	0.122*
C12	0.5870 (3)	0.6161 (7)	0.1558 (2)	0.0965 (12)
H12	0.6458	0.5341	0.1787	0.116*
C13	0.6081 (3)	0.7957 (7)	0.1656 (2)	0.0937 (11)
H13	0.6813	0.8364	0.1963	0.112*
C14	0.5226 (2)	0.9156 (5)	0.13061 (19)	0.0771 (9)
H14	0.5383	1.0378	0.1378	0.093*
O15	−0.13713 (16)	0.6565 (3)	−0.06912 (12)	0.0795 (6)
C16	−0.1335 (2)	0.6290 (4)	0.1117 (2)	0.0709 (8)
H16A	−0.1072	0.5297	0.1537	0.106*
H16B	−0.1920	0.5889	0.0564	0.106*
H16C	−0.1631	0.7205	0.1421	0.106*
O17	0.05736 (15)	0.7429 (3)	0.23962 (12)	0.0705 (6)
C18	0.2302 (2)	0.9323 (4)	0.21321 (17)	0.0726 (8)
H18A	0.3026	0.8811	0.2183	0.109*
H18B	0.2148	0.9150	0.2710	0.109*
H18C	0.2310	1.0585	0.2004	0.109*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0600 (12)	0.0600 (13)	0.0538 (12)	0.0080 (11)	0.0178 (10)	0.0070 (11)
N2	0.0790 (15)	0.0691 (15)	0.0534 (12)	0.0141 (13)	0.0260 (11)	0.0080 (11)
C3	0.0744 (18)	0.0637 (18)	0.0489 (14)	0.0156 (15)	0.0160 (13)	−0.0008 (13)
C3A	0.0534 (14)	0.0521 (13)	0.0428 (12)	0.0139 (12)	0.0088 (11)	0.0003 (11)
C4	0.0579 (15)	0.0520 (15)	0.0519 (14)	0.0117 (12)	0.0091 (12)	−0.0065 (12)
N5	0.0511 (11)	0.0527 (13)	0.0563 (12)	0.0056 (10)	0.0152 (9)	−0.0015 (10)
C6	0.0595 (15)	0.0509 (15)	0.0462 (13)	0.0128 (12)	0.0160 (12)	0.0006 (11)
N7	0.0520 (11)	0.0557 (12)	0.0419 (10)	0.0032 (10)	0.0092 (9)	0.0012 (9)
C7A	0.0543 (13)	0.0466 (13)	0.0468 (12)	0.0145 (12)	0.0162 (11)	0.0064 (11)
C8	0.0630 (16)	0.0637 (17)	0.0756 (17)	−0.0007 (14)	0.0275 (13)	0.0081 (14)
C9	0.0565 (15)	0.0669 (17)	0.0568 (14)	0.0002 (13)	0.0268 (12)	0.0021 (13)
C10	0.0636 (17)	0.072 (2)	0.110 (2)	0.0072 (16)	0.0207 (16)	0.0067 (18)
C11	0.096 (3)	0.084 (2)	0.130 (3)	0.027 (2)	0.044 (2)	0.021 (2)
C12	0.079 (2)	0.137 (4)	0.082 (2)	0.047 (2)	0.0378 (18)	0.021 (2)
C13	0.0597 (19)	0.143 (4)	0.078 (2)	0.012 (2)	0.0226 (15)	−0.015 (2)
C14	0.0610 (17)	0.094 (2)	0.0831 (19)	−0.0039 (17)	0.0327 (15)	−0.0126 (17)
O15	0.0662 (12)	0.0913 (15)	0.0668 (12)	−0.0064 (11)	0.0020 (10)	−0.0121 (11)
C16	0.0677 (17)	0.0635 (17)	0.0863 (19)	−0.0038 (14)	0.0316 (15)	−0.0029 (15)
O17	0.0825 (12)	0.0779 (14)	0.0543 (11)	−0.0013 (10)	0.0265 (9)	0.0033 (9)
C18	0.0718 (17)	0.085 (2)	0.0521 (14)	−0.0112 (15)	0.0081 (13)	−0.0018 (14)

Geometric parameters (Å, º)

N1—C7A	1.355 (3)	C8—H8B	0.9700
N1—N2	1.383 (3)	C9—C14	1.373 (3)
N1—C8	1.449 (3)	C9—C10	1.374 (4)
N2—C3	1.314 (3)	C10—C11	1.378 (4)
C3—C3A	1.395 (3)	C10—H10	0.9300
C3—H3	0.9300	C11—C12	1.368 (5)
C3A—C7A	1.371 (3)	C11—H11	0.9300
C3A—C4	1.434 (4)	C12—C13	1.362 (5)
C4—O15	1.220 (3)	C12—H12	0.9300
C4—N5	1.398 (3)	C13—C14	1.359 (5)
N5—C6	1.380 (3)	C13—H13	0.9300
N5—C16	1.465 (3)	C14—H14	0.9300
C6—O17	1.214 (3)	C16—H16A	0.9600
C6—N7	1.396 (3)	C16—H16B	0.9600
N7—C7A	1.366 (3)	C16—H16C	0.9600
N7—C18	1.463 (3)	C18—H18A	0.9600
C8—C9	1.507 (4)	C18—H18B	0.9600
C8—H8A	0.9700	C18—H18C	0.9600
C7A—N1—N2	110.08 (19)	C14—C9—C10	118.1 (3)
C7A—N1—C8	133.1 (2)	C14—C9—C8	118.9 (3)
N2—N1—C8	116.4 (2)	C10—C9—C8	122.9 (2)
C3—N2—N1	105.41 (19)	C9—C10—C11	120.6 (3)
N2—C3—C3A	111.7 (2)	C9—C10—H10	119.7
N2—C3—H3	124.1	C11—C10—H10	119.7
C3A—C3—H3	124.1	C12—C11—C10	120.0 (4)
C7A—C3A—C3	105.2 (2)	C12—C11—H11	120.0
C7A—C3A—C4	120.9 (2)	C10—C11—H11	120.0
C3—C3A—C4	133.8 (2)	C13—C12—C11	119.6 (3)
O15—C4—N5	120.9 (2)	C13—C12—H12	120.2
O15—C4—C3A	126.1 (2)	C11—C12—H12	120.2
N5—C4—C3A	113.0 (2)	C14—C13—C12	120.2 (3)
C6—N5—C4	126.2 (2)	C14—C13—H13	119.9
C6—N5—C16	116.0 (2)	C12—C13—H13	119.9
C4—N5—C16	117.8 (2)	C13—C14—C9	121.4 (3)
O17—C6—N5	121.3 (2)	C13—C14—H14	119.3
O17—C6—N7	120.5 (2)	C9—C14—H14	119.3
N5—C6—N7	118.2 (2)	N5—C16—H16A	109.5
C7A—N7—C6	117.86 (19)	N5—C16—H16B	109.5
C7A—N7—C18	124.0 (2)	H16A—C16—H16B	109.5
C6—N7—C18	117.76 (19)	N5—C16—H16C	109.5
N1—C7A—N7	128.7 (2)	H16A—C16—H16C	109.5
N1—C7A—C3A	107.5 (2)	H16B—C16—H16C	109.5
N7—C7A—C3A	123.7 (2)	N7—C18—H18A	109.5
N1—C8—C9	114.7 (2)	N7—C18—H18B	109.5
N1—C8—H8A	108.6	H18A—C18—H18B	109.5
C9—C8—H8A	108.6	N7—C18—H18C	109.5
N1—C8—H8B	108.6	H18A—C18—H18C	109.5
C9—C8—H8B	108.6	H18B—C18—H18C	109.5
H8A—C8—H8B	107.6
C7A—N1—N2—C3	1.9 (3)	N2—N1—C7A—C3A	−1.3 (3)
C8—N1—N2—C3	175.6 (2)	C8—N1—C7A—C3A	−173.7 (2)
N1—N2—C3—C3A	−1.7 (3)	C6—N7—C7A—N1	−179.2 (2)
N2—C3—C3A—C7A	0.9 (3)	C18—N7—C7A—N1	7.8 (4)
N2—C3—C3A—C4	179.6 (3)	C6—N7—C7A—C3A	1.9 (3)
C7A—C3A—C4—O15	177.9 (2)	C18—N7—C7A—C3A	−171.2 (2)
C3—C3A—C4—O15	−0.6 (5)	C3—C3A—C7A—N1	0.3 (3)
C7A—C3A—C4—N5	−1.1 (3)	C4—C3A—C7A—N1	−178.6 (2)
C3—C3A—C4—N5	−179.6 (2)	C3—C3A—C7A—N7	179.4 (2)
O15—C4—N5—C6	−179.8 (2)	C4—C3A—C7A—N7	0.5 (4)
C3A—C4—N5—C6	−0.8 (3)	C7A—N1—C8—C9	73.6 (3)
O15—C4—N5—C16	−1.8 (3)	N2—N1—C8—C9	−98.4 (2)
C3A—C4—N5—C16	177.2 (2)	N1—C8—C9—C14	−175.2 (2)
C4—N5—C6—O17	−178.5 (2)	N1—C8—C9—C10	4.6 (4)
C16—N5—C6—O17	3.5 (3)	C14—C9—C10—C11	−0.6 (4)
C4—N5—C6—N7	3.2 (3)	C8—C9—C10—C11	179.6 (3)
C16—N5—C6—N7	−174.9 (2)	C9—C10—C11—C12	−0.7 (5)
O17—C6—N7—C7A	178.1 (2)	C10—C11—C12—C13	1.7 (5)
N5—C6—N7—C7A	−3.6 (3)	C11—C12—C13—C14	−1.3 (5)
O17—C6—N7—C18	−8.4 (4)	C12—C13—C14—C9	0.0 (5)
N5—C6—N7—C18	170.0 (2)	C10—C9—C14—C13	0.9 (4)
N2—N1—C7A—N7	179.6 (2)	C8—C9—C14—C13	−179.3 (3)
C8—N1—C7A—N7	7.3 (4)