Cyclo­penta­deca­none 2,4-dinitro­phenyl­hydrazone

In the title compound, C₂₁H₃₂N₄O₄, no disorder is present in the 15-membered hydro­carbon ring, which exists in an unsymmetrical quinquangular [12345] conformation. The 2,4-dinitro­phenyl­hydrazone group is approximately perpendicular to the C₁₅ ring, with a dihedral angle of 84.66 (1)° between their best planes.

S1. Comment

Semiquantitative calculations for cyclopentadecane, (II), indicated that the first five lowest-energy conformations considered were all quinquangular and that the [33333] conformation was the most stable (Dale, 1973). Five triangular conformations were found among the next nine conformations in order of energy, but quadrangular conformations were absent (Dale, 1973).

MOLBUILD (Boyd, 1968; Boyd et al., 1973) force field calculations for cyclopentadecane also found five low-energy quinquangular conformations, with the [33333] of lowest strain energy (Anet & Rawdah, 1978). The low-temperature ¹H and ¹³C NMR spectra of (II) showed line broadening at the lowest attainable temperatures of 123 and 119 K, respectively, but decoalescence was not observed in either case (Cheng, 1973). Pawar et al. (2008) later recorded the ¹³C NMR spectra at temperatures to 100.3 K; spectra at the lowest temperatures were substantially more complicated than the two peaks in a ratio of 2:1 expected for the [33333] conformation at slow exchange. This conformation could be present but cannot be the sole conformation populated. In macrocyclic rings, a large number of minimum-energy structures can be populated, due to the existence of a high degree of rotational freedom. For example, 262 low-energy conformations were found within 3 kcal mol^-1 by MM2 for cycloheptadecane (Saunders et al., 1990).

The crystal structure of cyclopentadecanone phenylsemicarbazone showed an ordered structure with hydrogen-bonded dimers (van den Hoek et al., 1979), and an unexpected quadrangular conformation, viz. [3435], was found for the C₁₅ ring. An incomplete X-ray study of cyclopentadecanone was reported (Groth, 1976), but no comment on conformation was made. We have recently reported (Noe et al., 2008) the details of the structure of cyclopentadecanone, in which the C₁₅ ring has the quinquangular [13353] conformation. A preliminary X-ray study of cyclopentadecanone oxime indicated that the structure is highly disordered (Groth, 1979).

Although cyclopentadecanone 2,4-dinitrophenylhydrazone, (I), was reported by Brady (1931), no structural data are available in the literature. This paper reports an X-ray analysis of the crystal structure of (I) at 90 K. Representative torsion angles defining the conformation of the 15-membered ring are listed in Table 2. The 15-membered ring is present in a quinquangular [12345] conformation with C₁ symmetry, based on the method of Dale (1973). In that system of conformational designation, corner positions are defined, and the numbers of bonds between adjacent corners are listed in brackets, in order of increasing numbers. Corners that are not on adjacent C atoms are readily recognized by having gauche dihedral angles of the same sign on either side. For (I), these are found at ring carbons 2, 6, and 9 in Fig. 1. Adjacent corners may can more difficult to recognize. Using the examples given for cycloundecane, cyclotridecane, and cyclopentadecane by Anet & Rawdah (1978), we also assign carbons 11 and 12 as corners. The dihedral angle centered on these two C atoms is -78.94 (18)°, and the dihedral angles on either side of it are 155.55 (15) and 178.42 (14)°, which would correspond to a gauche bond, surrounded by two that are close to anti. These dihedral angles are similar to the values around the one-bond segment of the [13353] conformation of cyclopentadecane, as calculated by Anet & Rawdah (1978) (166, -78, and 150°). The section of the ring between C12 and C2 is a five-bond segment between corners. Thus, beginning at corner C12 and proceeding clockwise in Fig. 2, the designation in (I) is [12345].

The C1—N1—N2—C16 torsion angle in (I) is -174.11 (15)°. The 2,4-dinitrophenylhydrazone group is nearly planar, with a mean deviation of 0.053 Å for its 14 non-H atoms, and a maximum deviation of 0.208 (1) Å for atom O4. It is nearly perpendicular to the hydrocarbon ring, forming a dihedral angle of 84.66 (1)° with the best plane of the C₁₅ ring. Those 15 C atoms exhibit a mean deviation of 0.382 Å from coplanarity, with a maximum deviation of 0.835 (1) Å for atom C1.

A projection showing intramolecular hydrogen bonding as dashed lines is shown in Fig. 2, which also illustrates close intermolecular O···O contacts between nitro groups [O1···O1(2 - x, -y, 1 - z) = 2.865 (2) Å and O2···O4(-x, 1 - y, 1 - z) = 0.000 (0) Å].

The hydrogen bond is a discrete six-membered ring [graph set S(6); Etter, 1990]. Also evident in Fig. 2 is stacking of the parallel benzene rings related by the inversion center at (1/2, 1/2, 1/2). The interplanar spacing is 3.295 Å, but the rings are slipped, such that the centroid–centroid distance is 3.557 Å.

Related literature

For related literature, see: Anet & Rawdah (1978); Boyd (1968); Boyd et al. (1973); Brady (1931); Cheng (1973); Dale (1973); Etter (1990); Groth (1976, 1979); Hoek et al. (1979); Saunders et al. (1990).

S2. Experimental

Cyclopentadecanone 2,4-dinitrophenylhydrazone, (I), was synthesized by treatment of cyclopentadecanone (0.8 g) with a 2,4-dinitrophenylhydrazine solution (12 ml) prepared from 2,4-dinitrophenylhydrazine (1 g), concentrated sulfuric acid (5 ml), water (8 ml), and ethanol (25 ml). The dinitrophenylhydrazone derivative immediately precipitated from the solution, and was isolated by filteration, washed with water, and recrystallized from ethanol [m.p. 373–375 K; literature m.p. 378 K (Brady, 1931)]. The purity of the sample was established by its ¹³C NMR spectrum.

S3. Refinement

H atoms on C were placed in calculated positions, guided by difference maps, with C—H bond distances in the range 0.95–0.99° and with U_iso(H) values of 1.2U_eq(C), and thereafter treated as riding. The N—H hydrogen was refined freely.

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. Displacement ellipsoid plot (50% probability) of cyclopentadecanone 2,4-dinitrophenylhydrazone, (I).
	Fig. 2. The unit cell of (I), showing intramolecular hydrogen bonding and nitro–nitro contacts as dashed lines.

Cyclopentadecanone 2,4-dinitrophenylhydrazone

Crystal data

C21H32N4O4	Z = 2
Mr = 404.51	F(000) = 436
Triclinic, P1	Dx = 1.308 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2486 (14) Å	Cell parameters from 4123 reflections
b = 8.3234 (15) Å	θ = 2.5–29.3°
c = 17.731 (3) Å	µ = 0.09 mm^−1
α = 103.419 (12)°	T = 90 K
β = 94.044 (9)°	Lath, yellow
γ = 97.017 (13)°	0.33 × 0.10 × 0.02 mm
V = 1027.3 (3) Å^3

Data collection

Nonius KappaCCD with an Oxford Cryosystems Cryostream cooler diffractometer	3372 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.038
Graphite monochromator	θmax = 29.3°, θmin = 2.8°
ω scans with κ offsets	h = −9→9
16738 measured reflections	k = −10→10
4936 independent reflections	l = −23→23

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.051	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0302P)^2 + 0.5298P] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max < 0.001
4936 reflections	Δρmax = 0.37 e Å^−3
266 parameters	Δρmin = −0.24 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0153 (16)

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	0.87072 (16)	0.10477 (14)	0.48047 (7)	0.0192 (3)
O2	0.82365 (18)	0.18914 (16)	0.37503 (7)	0.0236 (3)
O3	0.28483 (19)	0.41631 (16)	0.31370 (7)	0.0272 (3)
O4	0.10538 (18)	0.49862 (15)	0.40401 (8)	0.0252 (3)
N1	0.56818 (19)	0.14734 (16)	0.65874 (8)	0.0139 (3)
N2	0.6406 (2)	0.15332 (17)	0.58880 (8)	0.0135 (3)
H2N	0.745 (3)	0.117 (2)	0.5767 (10)	0.016*
N3	0.77557 (19)	0.16912 (16)	0.43770 (8)	0.0144 (3)
N4	0.2347 (2)	0.42481 (17)	0.37939 (9)	0.0186 (3)
C1	0.6738 (2)	0.10401 (19)	0.70983 (9)	0.0135 (3)
C2	0.5831 (2)	0.0806 (2)	0.78126 (9)	0.0168 (4)
H2A	0.5843	−0.0365	0.7845	0.020*
H2B	0.4508	0.0977	0.7744	0.020*
C3	0.6735 (2)	0.1958 (2)	0.85892 (9)	0.0161 (4)
H3A	0.6269	0.1504	0.9020	0.019*
H3B	0.8102	0.1951	0.8616	0.019*
C4	0.6354 (2)	0.3759 (2)	0.87123 (10)	0.0165 (4)
H4A	0.4991	0.3783	0.8708	0.020*
H4B	0.6790	0.4216	0.8277	0.020*
C5	0.7340 (2)	0.4855 (2)	0.94836 (10)	0.0179 (4)
H5A	0.8694	0.4781	0.9491	0.021*
H5B	0.6876	0.4397	0.9914	0.021*
C6	0.7079 (3)	0.6702 (2)	0.96427 (10)	0.0202 (4)
H6A	0.5732	0.6773	0.9547	0.024*
H6B	0.7477	0.7234	1.0200	0.024*
C7	0.8160 (2)	0.7686 (2)	0.91478 (10)	0.0188 (4)
H7A	0.7699	0.8774	0.9197	0.023*
H7B	0.7912	0.7067	0.8594	0.023*
C8	1.0267 (2)	0.7994 (2)	0.93815 (10)	0.0170 (4)
H8A	1.0697	0.6914	0.9392	0.020*
H8B	1.0519	0.8719	0.9916	0.020*
C9	1.1408 (3)	0.8806 (2)	0.88389 (10)	0.0177 (4)
H9A	1.2691	0.9222	0.9095	0.021*
H9B	1.0838	0.9777	0.8750	0.021*
C10	1.1509 (2)	0.7599 (2)	0.80525 (10)	0.0177 (4)
H10A	1.1948	0.8246	0.7680	0.021*
H10B	1.0239	0.7011	0.7846	0.021*
C11	1.2819 (2)	0.6303 (2)	0.81037 (10)	0.0178 (4)
H11A	1.4118	0.6807	0.8083	0.021*
H11B	1.2756	0.6013	0.8613	0.021*
C12	1.2348 (2)	0.4698 (2)	0.74518 (10)	0.0161 (4)
H12A	1.2054	0.4999	0.6953	0.019*
H12B	1.3462	0.4117	0.7402	0.019*
C13	1.0700 (2)	0.3500 (2)	0.75891 (10)	0.0164 (4)
H13A	1.1003	0.3163	0.8078	0.020*
H13B	0.9587	0.4082	0.7650	0.020*
C14	1.0251 (2)	0.1951 (2)	0.69174 (9)	0.0149 (3)
H14A	1.1406	0.1437	0.6837	0.018*
H14B	0.9894	0.2307	0.6439	0.018*
C15	0.8694 (2)	0.0602 (2)	0.70121 (10)	0.0155 (4)
H15A	0.8616	−0.0356	0.6554	0.019*
H15B	0.9095	0.0210	0.7476	0.019*
C16	0.5419 (2)	0.21265 (19)	0.53597 (9)	0.0122 (3)
C17	0.6019 (2)	0.22337 (19)	0.46248 (9)	0.0131 (3)
C18	0.5001 (2)	0.28929 (19)	0.41090 (9)	0.0141 (3)
H18	0.5424	0.2945	0.3619	0.017*
C19	0.3366 (2)	0.3470 (2)	0.43182 (10)	0.0154 (4)
C20	0.2703 (2)	0.33826 (19)	0.50314 (10)	0.0158 (4)
H20	0.1567	0.3783	0.5165	0.019*
C21	0.3707 (2)	0.27143 (19)	0.55347 (10)	0.0145 (3)
H21	0.3243	0.2643	0.6015	0.017*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0182 (7)	0.0226 (7)	0.0196 (6)	0.0089 (5)	0.0016 (5)	0.0079 (5)
O2	0.0263 (7)	0.0317 (7)	0.0191 (7)	0.0105 (6)	0.0107 (6)	0.0129 (5)
O3	0.0281 (8)	0.0342 (8)	0.0217 (7)	0.0052 (6)	−0.0027 (6)	0.0126 (6)
O4	0.0196 (7)	0.0214 (7)	0.0358 (8)	0.0074 (6)	−0.0019 (6)	0.0087 (6)
N1	0.0164 (7)	0.0128 (7)	0.0122 (7)	−0.0004 (6)	0.0025 (6)	0.0036 (5)
N2	0.0126 (7)	0.0161 (7)	0.0122 (7)	0.0035 (6)	0.0023 (6)	0.0034 (6)
N3	0.0145 (7)	0.0135 (7)	0.0151 (7)	0.0016 (6)	0.0024 (6)	0.0031 (6)
N4	0.0157 (8)	0.0150 (7)	0.0238 (8)	−0.0004 (6)	−0.0041 (6)	0.0050 (6)
C1	0.0154 (9)	0.0086 (7)	0.0146 (8)	−0.0018 (6)	0.0006 (7)	0.0012 (6)
C2	0.0191 (9)	0.0157 (8)	0.0165 (9)	0.0017 (7)	0.0021 (7)	0.0059 (7)
C3	0.0172 (9)	0.0182 (8)	0.0145 (8)	0.0028 (7)	0.0021 (7)	0.0069 (7)
C4	0.0158 (9)	0.0185 (9)	0.0151 (8)	0.0023 (7)	0.0007 (7)	0.0046 (7)
C5	0.0197 (9)	0.0207 (9)	0.0133 (9)	0.0019 (7)	0.0013 (7)	0.0047 (7)
C6	0.0194 (10)	0.0221 (9)	0.0168 (9)	0.0021 (7)	0.0024 (7)	0.0005 (7)
C7	0.0199 (10)	0.0167 (9)	0.0191 (9)	0.0042 (7)	−0.0013 (7)	0.0032 (7)
C8	0.0205 (10)	0.0153 (8)	0.0142 (8)	0.0031 (7)	−0.0006 (7)	0.0018 (7)
C9	0.0194 (9)	0.0141 (8)	0.0188 (9)	0.0017 (7)	−0.0002 (7)	0.0033 (7)
C10	0.0191 (9)	0.0180 (9)	0.0158 (9)	0.0011 (7)	0.0014 (7)	0.0046 (7)
C11	0.0142 (9)	0.0199 (9)	0.0173 (9)	−0.0003 (7)	−0.0002 (7)	0.0026 (7)
C12	0.0147 (9)	0.0178 (9)	0.0150 (8)	0.0037 (7)	0.0009 (7)	0.0021 (7)
C13	0.0158 (9)	0.0167 (8)	0.0157 (9)	0.0017 (7)	0.0012 (7)	0.0027 (7)
C14	0.0135 (8)	0.0171 (8)	0.0144 (8)	0.0036 (7)	0.0019 (7)	0.0039 (7)
C15	0.0171 (9)	0.0133 (8)	0.0154 (8)	0.0019 (7)	0.0004 (7)	0.0024 (6)
C16	0.0135 (8)	0.0080 (7)	0.0137 (8)	−0.0012 (6)	−0.0002 (7)	0.0017 (6)
C17	0.0128 (8)	0.0097 (8)	0.0146 (8)	−0.0004 (6)	0.0004 (7)	0.0001 (6)
C18	0.0149 (9)	0.0121 (8)	0.0132 (8)	−0.0023 (6)	−0.0013 (7)	0.0019 (6)
C19	0.0139 (9)	0.0120 (8)	0.0188 (9)	−0.0005 (7)	−0.0042 (7)	0.0037 (7)
C20	0.0112 (8)	0.0121 (8)	0.0221 (9)	0.0014 (7)	0.0010 (7)	0.0008 (7)
C21	0.0140 (9)	0.0134 (8)	0.0147 (8)	−0.0004 (7)	0.0031 (7)	0.0014 (6)

Geometric parameters (Å, º)

O1—N3	1.2420 (17)	C8—H8A	0.9900
O2—N3	1.2289 (17)	C8—H8B	0.9900
O3—N4	1.2334 (19)	C9—C10	1.530 (2)
O4—N4	1.2329 (18)	C9—H9A	0.9900
N1—C1	1.288 (2)	C9—H9B	0.9900
N1—N2	1.3891 (19)	C10—C11	1.535 (2)
N2—C16	1.356 (2)	C10—H10A	0.9900
N2—H2N	0.869 (18)	C10—H10B	0.9900
N3—C17	1.451 (2)	C11—C12	1.534 (2)
N4—C19	1.459 (2)	C11—H11A	0.9900
C1—C2	1.508 (2)	C11—H11B	0.9900
C1—C15	1.516 (2)	C12—C13	1.531 (2)
C2—C3	1.533 (2)	C12—H12A	0.9900
C2—H2A	0.9900	C12—H12B	0.9900
C2—H2B	0.9900	C13—C14	1.522 (2)
C3—C4	1.526 (2)	C13—H13A	0.9900
C3—H3A	0.9900	C13—H13B	0.9900
C3—H3B	0.9900	C14—C15	1.539 (2)
C4—C5	1.529 (2)	C14—H14A	0.9900
C4—H4A	0.9900	C14—H14B	0.9900
C4—H4B	0.9900	C15—H15A	0.9900
C5—C6	1.535 (2)	C15—H15B	0.9900
C5—H5A	0.9900	C16—C21	1.417 (2)
C5—H5B	0.9900	C16—C17	1.421 (2)
C6—C7	1.526 (2)	C17—C18	1.385 (2)
C6—H6A	0.9900	C18—C19	1.375 (2)
C6—H6B	0.9900	C18—H18	0.9500
C7—C8	1.529 (2)	C19—C20	1.399 (2)
C7—H7A	0.9900	C20—C21	1.369 (2)
C7—H7B	0.9900	C20—H20	0.9500
C8—C9	1.531 (2)	C21—H21	0.9500
C1—N1—N2	116.64 (14)	C8—C9—H9B	109.1
C16—N2—N1	118.84 (13)	C10—C9—H9B	109.1
C16—N2—H2N	118.5 (12)	H9A—C9—H9B	107.8
N1—N2—H2N	122.7 (12)	C9—C10—C11	113.02 (14)
O2—N3—O1	122.26 (13)	C9—C10—H10A	109.0
O2—N3—C17	118.65 (13)	C11—C10—H10A	109.0
O1—N3—C17	119.08 (13)	C9—C10—H10B	109.0
O4—N4—O3	123.67 (14)	C11—C10—H10B	109.0
O4—N4—C19	117.92 (14)	H10A—C10—H10B	107.8
O3—N4—C19	118.39 (14)	C12—C11—C10	113.54 (14)
N1—C1—C2	115.12 (15)	C12—C11—H11A	108.9
N1—C1—C15	126.35 (15)	C10—C11—H11A	108.9
C2—C1—C15	118.28 (14)	C12—C11—H11B	108.9
C1—C2—C3	115.75 (14)	C10—C11—H11B	108.9
C1—C2—H2A	108.3	H11A—C11—H11B	107.7
C3—C2—H2A	108.3	C13—C12—C11	113.54 (14)
C1—C2—H2B	108.3	C13—C12—H12A	108.9
C3—C2—H2B	108.3	C11—C12—H12A	108.9
H2A—C2—H2B	107.4	C13—C12—H12B	108.9
C4—C3—C2	114.20 (13)	C11—C12—H12B	108.9
C4—C3—H3A	108.7	H12A—C12—H12B	107.7
C2—C3—H3A	108.7	C14—C13—C12	111.64 (14)
C4—C3—H3B	108.7	C14—C13—H13A	109.3
C2—C3—H3B	108.7	C12—C13—H13A	109.3
H3A—C3—H3B	107.6	C14—C13—H13B	109.3
C3—C4—C5	111.68 (14)	C12—C13—H13B	109.3
C3—C4—H4A	109.3	H13A—C13—H13B	108.0
C5—C4—H4A	109.3	C13—C14—C15	116.41 (14)
C3—C4—H4B	109.3	C13—C14—H14A	108.2
C5—C4—H4B	109.3	C15—C14—H14A	108.2
H4A—C4—H4B	107.9	C13—C14—H14B	108.2
C4—C5—C6	115.09 (14)	C15—C14—H14B	108.2
C4—C5—H5A	108.5	H14A—C14—H14B	107.3
C6—C5—H5A	108.5	C1—C15—C14	118.89 (13)
C4—C5—H5B	108.5	C1—C15—H15A	107.6
C6—C5—H5B	108.5	C14—C15—H15A	107.6
H5A—C5—H5B	107.5	C1—C15—H15B	107.6
C7—C6—C5	114.39 (14)	C14—C15—H15B	107.6
C7—C6—H6A	108.7	H15A—C15—H15B	107.0
C5—C6—H6A	108.7	N2—C16—C21	119.99 (14)
C7—C6—H6B	108.7	N2—C16—C17	123.59 (14)
C5—C6—H6B	108.7	C21—C16—C17	116.41 (14)
H6A—C6—H6B	107.6	C18—C17—C16	121.98 (15)
C6—C7—C8	112.98 (14)	C18—C17—N3	116.03 (14)
C6—C7—H7A	109.0	C16—C17—N3	121.98 (14)
C8—C7—H7A	109.0	C19—C18—C17	118.87 (15)
C6—C7—H7B	109.0	C19—C18—H18	120.6
C8—C7—H7B	109.0	C17—C18—H18	120.6
H7A—C7—H7B	107.8	C18—C19—C20	121.52 (15)
C7—C8—C9	114.12 (14)	C18—C19—N4	118.87 (15)
C7—C8—H8A	108.7	C20—C19—N4	119.57 (14)
C9—C8—H8A	108.7	C21—C20—C19	119.28 (15)
C7—C8—H8B	108.7	C21—C20—H20	120.4
C9—C8—H8B	108.7	C19—C20—H20	120.4
H8A—C8—H8B	107.6	C20—C21—C16	121.92 (15)
C8—C9—C10	112.57 (14)	C20—C21—H21	119.0
C8—C9—H9A	109.1	C16—C21—H21	119.0
C10—C9—H9A	109.1
C15—C1—C2—C3	66.69 (18)	N2—C16—C17—C18	−178.05 (16)
C1—C2—C3—C4	73.82 (18)	C21—C16—C17—C18	0.7 (2)
C2—C3—C4—C5	−178.22 (14)	N2—C16—C17—N3	0.6 (2)
C3—C4—C5—C6	178.25 (15)	C21—C16—C17—N3	179.36 (14)
C4—C5—C6—C7	−72.9 (2)	O2—N3—C17—C18	2.2 (2)
C5—C6—C7—C8	−71.38 (19)	O1—N3—C17—C18	−178.08 (14)
C6—C7—C8—C9	173.55 (14)	O2—N3—C17—C16	−176.59 (15)
C7—C8—C9—C10	−72.99 (18)	O1—N3—C17—C16	3.2 (2)
C8—C9—C10—C11	−74.00 (19)	C16—C17—C18—C19	0.4 (2)
C9—C10—C11—C12	155.55 (15)	N3—C17—C18—C19	−178.32 (14)
C10—C11—C12—C13	−78.94 (18)	C17—C18—C19—C20	−0.9 (2)
C11—C12—C13—C14	178.42 (14)	C17—C18—C19—N4	176.66 (15)
C12—C13—C14—C15	176.39 (14)	O4—N4—C19—C18	−168.96 (15)
C14—C15—C1—C2	−122.89 (16)	O3—N4—C19—C18	9.5 (2)
C13—C14—C15—C1	61.5 (2)	O4—N4—C19—C20	8.7 (2)
N1—C1—C15—C14	63.3 (2)	O3—N4—C19—C20	−172.85 (15)
C1—N1—N2—C16	−174.11 (15)	C18—C19—C20—C21	0.3 (2)
N2—N1—C1—C2	−173.57 (13)	N4—C19—C20—C21	−177.29 (15)
N2—N1—C1—C15	0.4 (2)	C19—C20—C21—C16	0.9 (2)
N1—C1—C2—C3	−118.78 (16)	N2—C16—C21—C20	177.43 (15)
N1—N2—C16—C21	1.7 (2)	C17—C16—C21—C20	−1.3 (2)
N1—N2—C16—C17	−179.59 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···O1	0.869 (18)	1.979 (18)	2.6254 (18)	130.2 (15)