Weak C—H...N[triple bond]C hydrogen bonds in the structures of two poly(cyano)-substituted ring systems

In benzene-1,2,3-tricarbonitrile, C₉H₃N₃, the packing of the two independent mol­ecules is three-dimensional and complex, involving inter alia bifurcated (C—H)₂...N systems from neighbouring CH groups. In [2.2]paracyclo­phane-4,5,12,13-tetra­carbonitrile, C₂₀H₁₂N₄, the [2.2]paracyclo­phane systems display the usual distortions, namely lengthened C—C bonds and widened sp³ angles in the bridges, narrow angles in the six-membered rings at the bridgehead atoms, and flattened boat conformations of the rings. The mol­ecules are linked by a series of C—H...N inter­actions to form layers parallel to the ab plane.

S1. Comment

Heating cyanoacetylene, (I), at 433 K results in the formation of 1,2,4- and 1,2,3-tricyanobenzene, (II); we have shown that this trimerization involves the intermediate generation of tricyano-Dewar benzenes (Witulski et al., 1990). We now report the crystal structure of (II). For the 1,2,4-isomer, we have so far been unable to obtain crystals of X-ray quality.

The tetra-substituted [2.2]paracyclophane (V) is formally a dimer of phthalonitrile, in which the two aromatic halves are held in fixed orientation by the ethano bridges. Considering that the monomer is, for example, the starting material for phthalocyanines, dimer (V) should also show interesting chemical behaviour. Having prepared (V) many years ago (Hopf & Lenich, 1974), we now report its structure. Since compounds (II) and (V) display similar C—H···N≡C interactions in the molecular packing, we present the structures together.

Compound (II) crystallizes with two independent molecules in the asymmetric unit (Fig. 1); these are, however, essentially identical. The molecular dimensions are as expected. The interplanar angle between the two molecules is 68.43 (6)°.

The main interest centres on the molecular packing. Reddy et al. (1995) have shown for 1,3,5-tricyanobenzene, the only other tricyanobenzene for which an X-ray structure analysis has been performed, that the packing is determined by weak C—H···N≡C hydrogen bonds (Desiraju & Steiner, 1999) that in projection give a pseudo-hexagonal pattern. Each H···N interaction is simultaneously part of both bifurcated (two H-atom donors to the same acceptor) and three-centre (one H-atom donor to two acceptors) hydrogen-bond systems; each H atom donates to two N atoms, and each N atom accepts two H-atom donors. The packing of (II), as might be expected in space group P2₁2₁2₁ and with two independent molecules, is three-dimensional and complicated, but a reasonably comprehensible overview can be obtained (Table 1 and Fig. 2) in terms of C—H···N interactions; there are no C—H···(ring centroid) contacts shorter than 3.49 Å.

Molecule 1 occupies the regions at z ≈ 0, 1/2 etc. and forms layers connected by hydrogen bond 4 (numbering according to the order in Table 1) via the 2₁ screw axis parallel to x. Molecule 2 occupies the regions z ≈ 1/4, 3/4 etc. and forms layers connected by hydrogen bond 10 via the 2₁ screw axis parallel to y. The main interest thus involves the interplay in the region at z ≈ 3/8, which is shown in Fig. 2; nine of the ten independent hydrogen bonds can be accommodated in this view.

The neighbouring CH groups C5/H5 and C6/H6 in both molecules form bifurcated hydrogen bonds to atom N1 of the other molecule; these (hyrogen bonds 6 and 7, and 1 and 2) are shown as thicker bonds in Fig. 2, and one such system (6/7) is implicitly recognizable in Fig. 1. In both molecules, atom H4 forms one reasonably linear hydrogen bond (4 and 5), whereas atoms H5 and H6 participate in a rather nonlinear but two-centre H bond (8 and 9, and 3 and 10) in addition to the bifurcated interactions. The (uncorrected) hydrogen bond length limit H···N has to be set at ca 2.9 Å to find all the interactions; this seems to be normal for the analysis of C—H···N≡C systems (e.g. Reddy et al., 1995). The correct compromise between the use of high or low contact radii, which may lead, respectively, either to a mass of unimportant detail or to an apparent lack of significant contacts, is not always easy to find.

The acceptor properties of the N atoms differ. Atoms N1 and N1' accept only the bifurcated interactions, atoms N2 and N3' each accept one branch of a three-centre system, atom N2' accepts one branch from each of two three-centre systems, and atom N3 accepts the two linear two-centre interactions. The topological difference between the two independent molecules is thus established.

The molecule of compound (V) (Fig. 3) has no imposed symmetry, but its noncrystallographic symmetry is close to 2/m (the r.m.s. deviation of non-H atoms is 0.034 Å). Molecular dimensions are largely as expected; in particular, the usual distortions of [2.2]paracyclophanes are observed (lengthened C—C bonds and widened sp³ angles in the bridges, narrow angles in the six-membered rings at the bridgehead atoms, and flattened boat conformation of the rings; Table 2).

Despite the more complicated nature of the molecule of (V), the molecular packing is conceptually much simpler than that of (II). It involves layers parallel to the ab plane, in which N atoms act as acceptors for weak C—H···N≡C hydrogen bonds (Table 3 and Fig. 4; hydorgen-bond numbers in Fig. 4 correspond to the order of Table 3). It is noteworthy that hydorgen bonds 5, 6, 7 and 8 form a concerted system of bifurcated and three-centre bonds; hydorgen bonds 1 and 2 form a further bifurcated system. As for (II), some of the contacts involve long H···N distances (up to 2.9 Å uncorrected), but their striking combined effect is that of a series of intermolecular links roughly parallel to the b axis. Only the contact H1B···N2 (hydrogen bond 3) is not observed within the layers; instead, it serves to connect the layers. There are no C—H···(ring centroid) contacts shorter than 3.18 Å.

Related literature

For related literature, see: Desiraju & Steiner (1999); Hopf (1995); Hopf & Lenich (1974); Hopf et al. (1981); Reddy et al. (1995); Witulski et al. (1990).

S2. Experimental

Compound (II) was prepared from cyanoacetylene (I) as previously described (Witulski et al., 1990); the spectroscopic and analytical data were consistent with those reported previously. Single crystals were obtained by slow cooling from carbon tetrachloride. Cyclophane (V) was prepared as described by Hopf & Lenich (1974) by the cycloaddition of dicyanoacetylene, (III) (Hopf, 1995), to 1,2,4,5-hexatetraene, (IV) (Hopf et al., 1981). All spectroscopic and analytical data agreed with those reported in the literature (Hopf & Lenich, 1974). Single crystals were obtained from acetonitrile.

S3. Refinement

Hydrogen atoms were included, starting from calculated positions, using a riding model with C—H 0.95 (aromatic), 0.99 (CH₂) Å. U(H) values were fixed at 1.2 × U(C) of the parent C atom. Compound (2) crystallizes by chance in a chiral space group, although the molecule is achiral. In the absence of significant anomalous scattering, Friedel opposite reflections were merged and the Flack parameter is meaningless.

Computing details

For both compounds, data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The two independent molecules of (II). Displacement ellipsoids represent 50% probability levels.
	Fig. 2. The packing of (II), viewed parallel to the y axis in the region z ≈ 0 (bottom) to 5/8 (top). Molecules generated from the second independent molecule (atom names with primes) are drawn with open bonds. Hydrogen bonds (see text) are indicated by dashed lines; one of each independent hydrogen bond is numbered according to the order of Table 1. The positioning of the labels is based on the space available in the figure; it is not possible to label all interactions for a given molecule without loss of clarity. Hydrogen bond 4 is not included in this view.
	Fig. 3. The molecule of (V). Displacement ellipsoids represent 50% probability levels.
	Fig. 4. The packing of (V), viewed perpendicular to the ab plane in the region z ≈1/4. Hydrogen bonds are indicated by dashed lines, drawn thicker for the bifurcated systems, and are numbered for one molecule according to their order in Table 3. H atoms not involved in hydrogen bonds have been omitted. Hydrogen bond 3 is not included in this view.

(II) benzene-1,2,3-tricarbonitrile

Crystal data

C9H3N3	Dx = 1.338 Mg m^−3
Mr = 153.14	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 8084 reflections
a = 6.7083 (12) Å	θ = 2.8–30.5°
b = 7.8650 (14) Å	µ = 0.09 mm^−1
c = 28.811 (5) Å	T = 133 K
V = 1520.1 (5) Å^3	Tablet, colourless
Z = 8	0.23 × 0.15 × 0.10 mm
F(000) = 624

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	2067 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.089
Graphite monochromator	θmax = 30.0°, θmin = 1.4°
Detector resolution: 8.192 pixels mm^-1	h = −9→9
ω–scan	k = −11→11
17402 measured reflections	l = −40→40
2581 independent reflections

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.115	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.051P)^2 + 0.3332P] where P = (Fo^2 + 2Fc^2)/3
2581 reflections	(Δ/σ)max < 0.001
217 parameters	Δρmax = 0.31 e Å^−3
0 restraints	Δρmin = −0.32 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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

- 2.8803 (0.0056) x - 6.4540 (0.0042) y + 10.8670 (0.0241) z = 2.1254 (0.0155)

* -0.0049 (0.0015) C1 * 0.0006 (0.0015) C2 * 0.0053 (0.0015) C3 * -0.0070 (0.0016) C4 * 0.0026 (0.0016) C5 * 0.0033 (0.0016) C6 - 0.0362 (0.0034) C7 0.0200 (0.0036) C8 0.0342 (0.0036) C9 - 0.0863 (0.0043) N1 0.0569 (0.0044) N2 0.0752 (0.0043) N3

Rms deviation of fitted atoms = 0.0045

- 3.0166 (0.0056) x + 6.5464 (0.0042) y + 9.3352 (0.0256) z = 9.6875 (0.0217)

Angle to previous plane (with approximate e.s.d.) = 68.43 (0.06)

* 0.0071 (0.0016) C1' * -0.0102 (0.0015) C2' * 0.0054 (0.0015) C3' * 0.0026 (0.0016) C4' * -0.0059 (0.0017) C5' * 0.0010 (0.0017) C6' 0.0584 (0.0038) C7' -0.0671 (0.0036) C8' 0.0601 (0.0036) C9' 0.1396 (0.0047) N1' -0.1270 (0.0044) N2' 0.1324 (0.0045) N3'

Rms deviation of fitted atoms = 0.0061

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
C1	0.0222 (3)	0.6459 (3)	0.58460 (7)	0.0198 (4)
C2	0.0493 (3)	0.5615 (3)	0.54219 (7)	0.0189 (4)
C3	0.2262 (3)	0.4698 (3)	0.53508 (7)	0.0211 (4)
C4	0.3721 (4)	0.4646 (3)	0.56952 (8)	0.0250 (5)
H4	0.4928	0.4044	0.5644	0.030*
C5	0.3404 (3)	0.5477 (3)	0.61133 (8)	0.0248 (5)
H5	0.4392	0.5424	0.6349	0.030*
C6	0.1670 (3)	0.6381 (3)	0.61911 (7)	0.0236 (5)
H6	0.1468	0.6946	0.6479	0.028*
C7	−0.1582 (3)	0.7432 (3)	0.59171 (7)	0.0227 (5)
C8	−0.1047 (4)	0.5687 (3)	0.50744 (7)	0.0232 (5)
C9	0.2568 (3)	0.3791 (3)	0.49195 (8)	0.0242 (5)
N1	−0.2990 (3)	0.8221 (3)	0.59664 (8)	0.0357 (5)
N2	−0.2307 (3)	0.5745 (3)	0.48088 (7)	0.0335 (5)
N3	0.2824 (3)	0.3049 (3)	0.45843 (7)	0.0340 (5)
C1'	0.6217 (3)	0.6396 (3)	0.79088 (7)	0.0209 (4)
C2'	0.8043 (3)	0.7238 (3)	0.78902 (7)	0.0202 (4)
C3'	0.9256 (3)	0.7255 (3)	0.82864 (8)	0.0227 (5)
C4'	0.8659 (4)	0.6406 (3)	0.86861 (8)	0.0262 (5)
H4'	0.9488	0.6413	0.8953	0.031*
C5'	0.6853 (4)	0.5548 (3)	0.86949 (8)	0.0273 (5)
H5'	0.6457	0.4960	0.8968	0.033*
C6'	0.5626 (4)	0.5543 (3)	0.83099 (8)	0.0254 (5)
H6'	0.4386	0.4960	0.8318	0.031*
C7'	0.4900 (4)	0.6434 (3)	0.75116 (8)	0.0261 (5)
C8'	0.8682 (4)	0.8049 (3)	0.74668 (8)	0.0255 (5)
C9'	1.1097 (4)	0.8192 (3)	0.82832 (9)	0.0302 (5)
N1'	0.3811 (4)	0.6491 (3)	0.72070 (7)	0.0410 (6)
N2'	0.9170 (4)	0.8666 (3)	0.71276 (8)	0.0393 (6)
N3'	1.2546 (3)	0.8962 (4)	0.82887 (9)	0.0467 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0186 (10)	0.0196 (10)	0.0211 (10)	−0.0010 (9)	0.0019 (8)	0.0014 (8)
C2	0.0229 (10)	0.0178 (10)	0.0158 (9)	−0.0007 (9)	0.0013 (8)	0.0035 (8)
C3	0.0221 (11)	0.0195 (10)	0.0219 (10)	−0.0001 (9)	0.0060 (9)	0.0020 (9)
C4	0.0188 (10)	0.0265 (11)	0.0298 (11)	0.0018 (10)	0.0021 (10)	0.0037 (10)
C5	0.0195 (11)	0.0301 (12)	0.0249 (11)	−0.0025 (10)	−0.0035 (9)	0.0031 (10)
C6	0.0261 (11)	0.0253 (11)	0.0194 (10)	−0.0056 (10)	−0.0002 (9)	0.0004 (9)
C7	0.0236 (11)	0.0244 (11)	0.0202 (10)	−0.0010 (10)	0.0015 (9)	−0.0005 (9)
C8	0.0280 (12)	0.0234 (10)	0.0183 (9)	0.0046 (10)	0.0028 (9)	0.0012 (8)
C9	0.0231 (11)	0.0234 (11)	0.0261 (10)	0.0015 (10)	0.0039 (10)	0.0034 (9)
N1	0.0318 (12)	0.0367 (12)	0.0384 (12)	0.0084 (10)	0.0018 (10)	−0.0024 (10)
N2	0.0375 (12)	0.0382 (12)	0.0247 (10)	0.0067 (11)	−0.0057 (10)	−0.0002 (9)
N3	0.0387 (12)	0.0325 (11)	0.0309 (11)	0.0026 (10)	0.0081 (10)	−0.0022 (9)
C1'	0.0205 (10)	0.0238 (10)	0.0185 (9)	−0.0001 (10)	−0.0006 (9)	0.0018 (9)
C2'	0.0204 (10)	0.0191 (10)	0.0210 (10)	0.0022 (9)	0.0024 (8)	−0.0021 (8)
C3'	0.0205 (10)	0.0215 (10)	0.0259 (11)	0.0023 (9)	0.0005 (9)	−0.0050 (9)
C4'	0.0313 (12)	0.0260 (11)	0.0212 (10)	0.0055 (11)	−0.0074 (10)	−0.0034 (9)
C5'	0.0371 (13)	0.0257 (11)	0.0190 (10)	0.0017 (11)	0.0005 (10)	0.0031 (9)
C6'	0.0260 (11)	0.0261 (11)	0.0241 (11)	−0.0063 (10)	−0.0003 (9)	0.0019 (9)
C7'	0.0246 (11)	0.0330 (12)	0.0208 (9)	−0.0021 (10)	0.0011 (9)	0.0023 (10)
C8'	0.0231 (11)	0.0257 (11)	0.0277 (11)	−0.0010 (10)	0.0040 (10)	−0.0007 (9)
C9'	0.0240 (12)	0.0342 (13)	0.0324 (12)	0.0013 (11)	0.0007 (10)	−0.0108 (11)
N1'	0.0360 (12)	0.0613 (16)	0.0255 (10)	0.0002 (13)	−0.0063 (10)	0.0006 (11)
N2'	0.0408 (13)	0.0404 (13)	0.0367 (11)	−0.0041 (12)	0.0101 (10)	0.0079 (11)
N3'	0.0279 (12)	0.0551 (16)	0.0571 (15)	−0.0090 (12)	0.0017 (12)	−0.0152 (13)

Geometric parameters (Å, º)

C1—C6	1.392 (3)	C2'—C3'	1.402 (3)
C1—C2	1.402 (3)	C2'—C8'	1.442 (3)
C1—C7	1.446 (3)	C3'—C4'	1.390 (3)
C2—C3	1.403 (3)	C3'—C9'	1.438 (3)
C2—C8	1.440 (3)	C4'—C5'	1.386 (4)
C3—C4	1.394 (3)	C5'—C6'	1.381 (3)
C3—C9	1.447 (3)	C7'—N1'	1.143 (3)
C4—C5	1.387 (3)	C8'—N2'	1.139 (3)
C5—C6	1.381 (3)	C9'—N3'	1.146 (3)
C7—N1	1.139 (3)	C4—H4	0.9500
C8—N2	1.141 (3)	C5—H5	0.9500
C9—N3	1.142 (3)	C6—H6	0.9500
C1'—C2'	1.393 (3)	C4'—H4'	0.9500
C1'—C6'	1.394 (3)	C5'—H5'	0.9500
C1'—C7'	1.446 (3)	C6'—H6'	0.9500
C6—C1—C2	120.7 (2)	C4'—C3'—C2'	120.2 (2)
C6—C1—C7	120.42 (19)	C4'—C3'—C9'	119.9 (2)
C2—C1—C7	118.86 (19)	C2'—C3'—C9'	119.9 (2)
C1—C2—C3	118.70 (19)	C5'—C4'—C3'	120.0 (2)
C1—C2—C8	119.59 (19)	C6'—C5'—C4'	120.5 (2)
C3—C2—C8	121.70 (19)	C5'—C6'—C1'	119.6 (2)
C4—C3—C2	120.3 (2)	N1'—C7'—C1'	177.6 (3)
C4—C3—C9	119.8 (2)	N2'—C8'—C2'	178.7 (3)
C2—C3—C9	119.9 (2)	N3'—C9'—C3'	178.4 (3)
C5—C4—C3	119.8 (2)	C5—C4—H4	120.1
C6—C5—C4	120.8 (2)	C3—C4—H4	120.1
C5—C6—C1	119.6 (2)	C6—C5—H5	119.6
N1—C7—C1	178.6 (3)	C4—C5—H5	119.6
N2—C8—C2	178.1 (2)	C5—C6—H6	120.2
N3—C9—C3	178.6 (3)	C1—C6—H6	120.2
C2'—C1'—C6'	120.72 (19)	C5'—C4'—H4'	120.0
C2'—C1'—C7'	119.8 (2)	C3'—C4'—H4'	120.0
C6'—C1'—C7'	119.5 (2)	C6'—C5'—H5'	119.7
C1'—C2'—C3'	118.92 (19)	C4'—C5'—H5'	119.7
C1'—C2'—C8'	120.3 (2)	C5'—C6'—H6'	120.2
C3'—C2'—C8'	120.8 (2)	C1'—C6'—H6'	120.2
C6—C1—C2—C3	−0.4 (3)	C6'—C1'—C2'—C3'	−1.8 (3)
C7—C1—C2—C3	178.81 (19)	C7'—C1'—C2'—C3'	176.9 (2)
C6—C1—C2—C8	178.7 (2)	C6'—C1'—C2'—C8'	177.1 (2)
C7—C1—C2—C8	−2.0 (3)	C7'—C1'—C2'—C8'	−4.1 (3)
C1—C2—C3—C4	−0.5 (3)	C1'—C2'—C3'—C4'	1.7 (3)
C8—C2—C3—C4	−179.7 (2)	C8'—C2'—C3'—C4'	−177.2 (2)
C1—C2—C3—C9	178.9 (2)	C1'—C2'—C3'—C9'	−176.7 (2)
C8—C2—C3—C9	−0.2 (3)	C8'—C2'—C3'—C9'	4.4 (3)
C2—C3—C4—C5	1.3 (3)	C2'—C3'—C4'—C5'	−0.5 (3)
C9—C3—C4—C5	−178.2 (2)	C9'—C3'—C4'—C5'	177.9 (2)
C3—C4—C5—C6	−1.0 (3)	C3'—C4'—C5'—C6'	−0.6 (4)
C4—C5—C6—C1	0.0 (3)	C4'—C5'—C6'—C1'	0.5 (4)
C2—C1—C6—C5	0.7 (3)	C2'—C1'—C6'—C5'	0.8 (4)
C7—C1—C6—C5	−178.5 (2)	C7'—C1'—C6'—C5'	−178.0 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C5′—H5′···N1^i	0.95	2.71	3.320 (3)	123
C6′—H6′···N1^i	0.95	2.64	3.288 (3)	125
C5′—H5′···N2^ii	0.95	2.55	3.380 (3)	146
C4—H4···N3^iii	0.95	2.63	3.566 (3)	169
C4′—H4′···N3^iv	0.95	2.60	3.528 (3)	167
C5—H5···N1′	0.95	2.64	3.262 (3)	124
C6—H6···N1′	0.95	2.65	3.261 (3)	123
C5—H5···N3′^v	0.95	2.57	3.430 (3)	150
C6—H6···N2′^vi	0.95	2.78	3.650 (3)	154
C6′—H6′···N2′^vii	0.95	2.89	3.758 (3)	152

Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) −x+1/2, −y+1, z+1/2; (iii) x+1/2, −y+1/2, −z+1; (iv) −x+3/2, −y+1, z+1/2; (v) −x+2, y−1/2, −z+3/2; (vi) x−1, y, z; (vii) −x+1, y−1/2, −z+3/2.

(V) [2.2]paracyclophane-4,5,12,13-tetracarbonitrile

Crystal data

C20H12N4	F(000) = 640
Mr = 308.34	Dx = 1.385 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 7.0277 (6) Å	Cell parameters from 5499 reflections
b = 15.1197 (14) Å	θ = 2.7–30.4°
c = 14.3219 (14) Å	µ = 0.09 mm^−1
β = 103.603 (4)°	T = 133 K
V = 1479.1 (2) Å^3	Tablet, pale yellow
Z = 4	0.40 × 0.22 × 0.12 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	3137 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.032
Graphite monochromator	θmax = 30.0°, θmin = 2.0°
Detector resolution: 8.192 pixels mm^-1	h = −9→9
ω–scan	k = −21→21
16873 measured reflections	l = −20→20
4321 independent reflections

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.130	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0788P)^2] where P = (Fo^2 + 2Fc^2)/3
4321 reflections	(Δ/σ)max < 0.001
217 parameters	Δρmax = 0.44 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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

- 5.8445 (0.0029) x + 1.1418 (0.0062) y + 10.4596 (0.0071) z = 1.8821 (0.0054)

* -0.0048 (0.0005) C4 * 0.0049 (0.0005) C5 * -0.0050 (0.0005) C7 * 0.0049 (0.0005) C8 - 0.1576 (0.0015) C3 - 0.1613 (0.0015) C6

Rms deviation of fitted atoms = 0.0049

5.8515 (0.0030) x - 1.3561 (0.0063) y - 10.4123 (0.0073) z = 1.0568 (0.0054)

Angle to previous plane (with approximate e.s.d.) = 0.84 (0.09)

* -0.0003 (0.0005) C12 * 0.0003 (0.0005) C13 * -0.0003 (0.0005) C15 * 0.0003 (0.0005) C16 - 0.1616 (0.0015) C11 - 0.1673 (0.0015) C14

Rms deviation of fitted atoms = 0.0003

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
C1	0.28446 (16)	0.53374 (8)	0.06102 (7)	0.0219 (2)
H1A	0.2630	0.4720	0.0378	0.026*
H1B	0.2664	0.5728	0.0041	0.026*
C2	0.12622 (15)	0.55817 (7)	0.11976 (7)	0.0191 (2)
H2A	0.0502	0.6102	0.0897	0.023*
H2B	0.0342	0.5081	0.1165	0.023*
C3	0.21831 (14)	0.57865 (7)	0.22369 (7)	0.0163 (2)
C4	0.26693 (15)	0.66479 (7)	0.25606 (7)	0.0165 (2)
C5	0.41777 (15)	0.67975 (7)	0.33964 (7)	0.0173 (2)
C6	0.52242 (15)	0.60906 (7)	0.38994 (7)	0.0187 (2)
C7	0.44105 (16)	0.52497 (7)	0.36861 (7)	0.0191 (2)
H7	0.4892	0.4771	0.4104	0.023*
C8	0.29143 (15)	0.50989 (7)	0.28759 (7)	0.0183 (2)
H8	0.2380	0.4522	0.2754	0.022*
C9	0.73036 (16)	0.61900 (8)	0.44893 (8)	0.0240 (2)
H9A	0.7485	0.5812	0.5068	0.029*
H9B	0.7523	0.6812	0.4705	0.029*
C10	0.88759 (15)	0.59252 (7)	0.39058 (8)	0.0206 (2)
H10A	0.9821	0.6416	0.3940	0.025*
H10B	0.9609	0.5399	0.4208	0.025*
C11	0.79553 (14)	0.57232 (7)	0.28656 (7)	0.0173 (2)
C12	0.74545 (15)	0.48613 (7)	0.25415 (7)	0.0163 (2)
C13	0.59387 (15)	0.47160 (7)	0.17079 (7)	0.0166 (2)
C14	0.49179 (15)	0.54304 (7)	0.12023 (7)	0.0180 (2)
C15	0.57641 (16)	0.62667 (7)	0.14085 (7)	0.0200 (2)
H15	0.5314	0.6745	0.0983	0.024*
C16	0.72463 (16)	0.64100 (7)	0.22221 (8)	0.0197 (2)
H16	0.7792	0.6985	0.2346	0.024*
C17	0.18239 (15)	0.73888 (7)	0.19756 (8)	0.0196 (2)
C18	0.47709 (16)	0.76971 (7)	0.36423 (8)	0.0214 (2)
C19	0.82807 (15)	0.41157 (7)	0.31194 (8)	0.0202 (2)
C20	0.53118 (15)	0.38252 (7)	0.14453 (7)	0.0191 (2)
N1	0.11400 (15)	0.79703 (7)	0.14967 (7)	0.0284 (2)
N2	0.52251 (16)	0.84139 (7)	0.38263 (8)	0.0318 (3)
N3	0.89486 (15)	0.35262 (7)	0.35901 (7)	0.0299 (2)
N4	0.48109 (15)	0.31205 (7)	0.12168 (7)	0.0286 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0214 (5)	0.0276 (6)	0.0150 (5)	0.0061 (4)	0.0009 (4)	−0.0009 (4)
C2	0.0167 (5)	0.0202 (5)	0.0190 (5)	−0.0016 (4)	0.0014 (4)	−0.0034 (4)
C3	0.0127 (4)	0.0185 (5)	0.0183 (5)	−0.0011 (4)	0.0047 (4)	−0.0017 (4)
C4	0.0144 (5)	0.0184 (5)	0.0171 (5)	−0.0003 (4)	0.0048 (4)	−0.0010 (4)
C5	0.0159 (5)	0.0199 (5)	0.0168 (5)	−0.0016 (4)	0.0052 (4)	−0.0031 (4)
C6	0.0175 (5)	0.0244 (6)	0.0145 (5)	0.0004 (4)	0.0046 (4)	−0.0015 (4)
C7	0.0206 (5)	0.0205 (5)	0.0176 (5)	0.0032 (4)	0.0072 (4)	0.0027 (4)
C8	0.0180 (5)	0.0171 (5)	0.0214 (5)	−0.0008 (4)	0.0078 (4)	−0.0002 (4)
C9	0.0193 (5)	0.0342 (6)	0.0169 (5)	0.0019 (5)	0.0008 (4)	−0.0028 (4)
C10	0.0160 (5)	0.0224 (5)	0.0217 (5)	−0.0012 (4)	0.0011 (4)	−0.0028 (4)
C11	0.0133 (5)	0.0193 (5)	0.0201 (5)	0.0000 (4)	0.0053 (4)	−0.0015 (4)
C12	0.0145 (4)	0.0166 (5)	0.0181 (5)	0.0013 (4)	0.0045 (4)	0.0003 (4)
C13	0.0162 (5)	0.0182 (5)	0.0160 (5)	0.0005 (4)	0.0047 (4)	−0.0009 (4)
C14	0.0194 (5)	0.0210 (5)	0.0142 (5)	0.0039 (4)	0.0053 (4)	0.0001 (4)
C15	0.0223 (5)	0.0200 (5)	0.0193 (5)	0.0044 (4)	0.0082 (4)	0.0036 (4)
C16	0.0192 (5)	0.0186 (5)	0.0237 (5)	−0.0002 (4)	0.0095 (4)	0.0001 (4)
C17	0.0184 (5)	0.0192 (5)	0.0212 (5)	−0.0028 (4)	0.0046 (4)	−0.0034 (4)
C18	0.0184 (5)	0.0248 (6)	0.0201 (5)	−0.0017 (4)	0.0029 (4)	−0.0040 (4)
C19	0.0171 (5)	0.0210 (5)	0.0206 (5)	−0.0005 (4)	0.0007 (4)	−0.0021 (4)
C20	0.0173 (5)	0.0216 (5)	0.0174 (5)	0.0018 (4)	0.0022 (4)	0.0006 (4)
N1	0.0306 (5)	0.0225 (5)	0.0305 (5)	0.0014 (4)	0.0040 (4)	0.0028 (4)
N2	0.0307 (6)	0.0277 (6)	0.0340 (6)	−0.0064 (4)	0.0019 (4)	−0.0077 (4)
N3	0.0291 (6)	0.0249 (5)	0.0308 (5)	0.0011 (4)	−0.0031 (4)	0.0030 (4)
N4	0.0303 (5)	0.0239 (5)	0.0295 (5)	−0.0023 (4)	0.0027 (4)	−0.0023 (4)

Geometric parameters (Å, º)

C1—C14	1.5102 (14)	C13—C20	1.4394 (15)
C1—C2	1.5877 (15)	C14—C15	1.3990 (15)
C2—C3	1.5091 (14)	C15—C16	1.3852 (15)
C3—C4	1.3977 (14)	C17—N1	1.1487 (14)
C3—C8	1.4004 (14)	C18—N2	1.1430 (14)
C4—C5	1.4180 (14)	C19—N3	1.1491 (14)
C4—C17	1.4407 (15)	C20—N4	1.1455 (14)
C5—C6	1.3974 (15)	C1—H1A	0.9900
C5—C18	1.4418 (15)	C1—H1B	0.9900
C6—C7	1.3981 (15)	C2—H2A	0.9900
C6—C9	1.5137 (14)	C2—H2B	0.9900
C7—C8	1.3892 (15)	C7—H7	0.9500
C9—C10	1.5856 (15)	C8—H8	0.9500
C10—C11	1.5092 (14)	C9—H9A	0.9900
C11—C16	1.4001 (14)	C9—H9B	0.9900
C11—C12	1.4002 (14)	C10—H10A	0.9900
C12—C13	1.4178 (14)	C10—H10B	0.9900
C12—C19	1.4377 (14)	C15—H15	0.9500
C13—C14	1.4005 (14)	C16—H16	0.9500
C14—C1—C2	112.60 (8)	N1—C17—C4	178.89 (12)
C3—C2—C1	112.28 (8)	N2—C18—C5	179.11 (13)
C4—C3—C8	116.84 (9)	N3—C19—C12	179.21 (12)
C4—C3—C2	122.22 (9)	N4—C20—C13	178.59 (11)
C8—C3—C2	119.90 (9)	C14—C1—H1A	109.1
C3—C4—C5	120.30 (9)	C2—C1—H1A	109.1
C3—C4—C17	119.76 (9)	C14—C1—H1B	109.1
C5—C4—C17	119.41 (9)	C2—C1—H1B	109.1
C6—C5—C4	120.76 (9)	H1A—C1—H1B	107.8
C6—C5—C18	120.58 (9)	C3—C2—H2A	109.1
C4—C5—C18	118.19 (9)	C1—C2—H2A	109.1
C5—C6—C7	116.37 (9)	C3—C2—H2B	109.1
C5—C6—C9	122.26 (10)	C1—C2—H2B	109.1
C7—C6—C9	120.25 (10)	H2A—C2—H2B	107.9
C8—C7—C6	121.47 (10)	C8—C7—H7	119.3
C7—C8—C3	120.88 (10)	C6—C7—H7	119.3
C6—C9—C10	112.44 (8)	C7—C8—H8	119.6
C11—C10—C9	112.41 (8)	C3—C8—H8	119.6
C16—C11—C12	116.70 (9)	C6—C9—H9A	109.1
C16—C11—C10	120.21 (9)	C10—C9—H9A	109.1
C12—C11—C10	122.11 (9)	C6—C9—H9B	109.1
C11—C12—C13	120.25 (9)	C10—C9—H9B	109.1
C11—C12—C19	120.20 (9)	H9A—C9—H9B	107.8
C13—C12—C19	119.01 (9)	C11—C10—H10A	109.1
C14—C13—C12	120.53 (9)	C9—C10—H10A	109.1
C14—C13—C20	119.90 (9)	C11—C10—H10B	109.1
C12—C13—C20	119.22 (9)	C9—C10—H10B	109.1
C15—C14—C13	116.57 (9)	H10A—C10—H10B	107.9
C15—C14—C1	120.58 (9)	C16—C15—H15	119.4
C13—C14—C1	121.85 (10)	C14—C15—H15	119.4
C16—C15—C14	121.14 (10)	C15—C16—H16	119.4
C15—C16—C11	121.23 (10)	C11—C16—H16	119.4
C14—C1—C2—C3	−4.26 (13)	C6—C9—C10—C11	5.82 (14)
C1—C2—C3—C4	93.18 (12)	C9—C10—C11—C16	74.29 (13)
C1—C2—C3—C8	−74.78 (12)	C9—C10—C11—C12	−94.03 (12)
C8—C3—C4—C5	13.97 (14)	C16—C11—C12—C13	−14.72 (15)
C2—C3—C4—C5	−154.34 (10)	C10—C11—C12—C13	153.98 (10)
C8—C3—C4—C17	−174.39 (9)	C16—C11—C12—C19	173.79 (9)
C2—C3—C4—C17	17.30 (15)	C10—C11—C12—C19	−17.51 (15)
C3—C4—C5—C6	1.15 (15)	C11—C12—C13—C14	−0.36 (15)
C17—C4—C5—C6	−170.51 (9)	C19—C12—C13—C14	171.23 (9)
C3—C4—C5—C18	173.34 (9)	C11—C12—C13—C20	−173.59 (9)
C17—C4—C5—C18	1.68 (15)	C19—C12—C13—C20	−2.00 (15)
C4—C5—C6—C7	−15.22 (15)	C12—C13—C14—C15	15.34 (15)
C18—C5—C6—C7	172.78 (9)	C20—C13—C14—C15	−171.47 (9)
C4—C5—C6—C9	152.73 (10)	C12—C13—C14—C1	−153.32 (10)
C18—C5—C6—C9	−19.28 (15)	C20—C13—C14—C1	19.86 (15)
C5—C6—C7—C8	14.39 (15)	C2—C1—C14—C15	−75.29 (12)
C9—C6—C7—C8	−153.82 (10)	C2—C1—C14—C13	92.93 (12)
C6—C7—C8—C3	0.73 (16)	C13—C14—C15—C16	−15.37 (15)
C4—C3—C8—C7	−15.00 (15)	C1—C14—C15—C16	153.44 (10)
C2—C3—C8—C7	153.60 (10)	C14—C15—C16—C11	0.21 (16)
C5—C6—C9—C10	−94.77 (12)	C12—C11—C16—C15	14.94 (15)
C7—C6—C9—C10	72.72 (13)	C10—C11—C16—C15	−153.99 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···N1^i	0.95	2.69	3.3654 (15)	129
C7—H7···N1^i	0.95	2.90	3.4710 (15)	120
C1—H1B···N2^ii	0.99	2.50	3.3569 (15)	145
C2—H2B···N2^i	0.99	2.55	3.4380 (15)	149
C10—H10A···N4^iii	0.99	2.60	3.4606 (15)	145
C15—H15···N3^iii	0.95	2.78	3.4221 (15)	125
C16—H16···N3^iii	0.95	2.82	3.4403 (15)	124
C16—H16···N4^iii	0.95	2.90	3.7133 (15)	145

Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+3/2, y+1/2, −z+1/2.