cis- and trans-2-(4-tert-Butylcyclohexyloxy)-1,3,5-trinitrobenzene

The structures of cis- and trans-2-(4-tert-butyl­cyclo­hexyl­oxy)-1,3,5-tri­nitro­benzene, C₁₆H₂₁N₃O₇, (I) and (II), respectively, were determined at low temperature in order to obtain accurate structural parameters for comparison purposes. The C_alkyl-O_ether bond distances are 1.497 (2) and 1.491 (2) Å for (I) and (II), respectively.

S1. Comment

This report forms part of our structural studies on cyclohexanes substituted with ester and ether derivatives of varying electron demand (White & Robertson, 1992; White et al., 1996, 2000). Previous work reported by Kirby and coworkers (Kirby & Allen, 1984; Briggs et al., 1984) has shown that Csp³—O bond distances are sensitive both to the donor ability of bonds which are antiperiplanar to the oxygen substituent, and also to the electron demand of the oxygen substituent itself. The Csp³—O bond distance was found to be linearly related to the electron demand of the oxygen substituent, and the slope of the plot was sensitive to the donor ability of bonds which were antiperiplanar to the C—O bond, and therefore able to donate electron density into the C—O antibonding orbital. This structural method for detecting electronic interactions in the ground state was referred to as the `variable oxygen probe' (Kirby et al., 1992).

The present low-temperature structural study is part of our efforts to apply the variable oxygen probe to the important question, Which is the better donor, a C—H bond or a C—C bond? Thus, we have embarked on a series of structural studies on ester and ether derivatives of cyclohexane, in which the oxygen substituent is constrained to occupy both axial and equatorial positions. An axial oxygen substituent has two antiperiplanar C—H bonds which can donate electron density into the C—O antibonding orbital (Scheme 2), whereas an equatorial oxygen substituent has two ring C—C bonds which can donate electron density into the C—O antibonding orbital. It is hoped that a comparison of the plots obtained for a range of oxygen substituents of varying electron demand will allow the distinction of the donor abilities of C—H and C—C bonds. The results for the title compounds, (I) and (II), are presented here. \sch

The structures of (I) and (II) were determined at 130 K to minimize the unwanted effects of thermal motion. Selected structural parameters for (I) and (II) are summarized in Tables 1 and 2, respectively.

The picrate (1,3,5-trinitrobenzene) moiety in both structures adopts the same conformation with respect to both the nitro substituents and the O-alkyl substituent. In both structures, the para nitro substituent is essentially coplanar with the aromatic ring, and one of the ortho nitro substituents is twisted slightly from the plane of the aromatic ring (ca 30°), while the second ortho nitro substituent is close to orthogonal. The conformation of the ortho nitro substituents presumably represents a compromise between the electron preference of the nitro group to be coplanar with the aromatic ring and the need to minimize steric interactions with the neighbouring oxygen substituent.

The conformation of the O-alkyl substituent, as defined by the dihedral angles C1—O1—C11—C12 and C1—O1—C11—C16, is essentially identical in each structure. While this conformation does not allow effective delocalization of an oxygen lone pair into the electron-deficient aromatic ring, a coplanar conformation would suffer from severe steric interaction between atom C1 and one of the ortho nitro substituents.

An examination of the bond angles O1—C1—C2 and O1—C1—C6 suggests that there is no significant strain associated with the axial substituent. This is consistent with the findings of Steiner (Steiner & Saenger, 1998), who examined a number of oxo-substituted cyclohexanes.

The C1—O1 distances in (I) and (II) are 1.497 (2) and 1.491 (2) Å, respectively. Although the axial picrate appears to have a slightly longer C—O bond than the corresponding equatorial picrate, this is barely significant. The C—C bond distances within the cyclohexane rings of both structures follow similar patterns, having the C1—C2 and C1—C6 bonds both shorter than the C2—C3 and C5—C6 bonds, and the C3—C4 and C4—C5 bonds, reflecting the expected effects of the strongly electron-withdrawing picryl substituent.

There are no significant differences in the C2—C3 and C5—C6 bond distances between the two structures. Thus, there are no observable structural effects of hyperconjugation of the antiperiplanar C—C bonds with the C1—O1 antibonding orbital in (II).

S2. Experimental

Compounds (I) and (II) were prepared by reaction of cis- and trans-cyclohexanol with 2,4,6-trinitrofluorobenzene in diethylether in the presence of an equivalent of pyridine. cis-4-tert-Butylcyclohexanol in pyridine/diethyl ether was treated with picryl fluoride to afford (I). Brown needles (m.p. 382–385 K) were grown from methanol. trans-4-tert-Butylcyclohexanol was treated in the same manner to prepare (II); recrystallization from pentane gave dark brown slabs (m.p. 381–383 K).

S3. Refinement

H atoms were placed in geometrical positions and treated as riding, with C—H = 0.95–1.00 Å and U_iso(H) = 1.2U_eq(C). Are these the correct restraints?

Computing details

For both compounds, data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: Please provide missing details; data reduction: PROCESS_DATA (Gable et al., 1994); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP (Zsolnai, 1994).

Figures

	Fig. 1. A view of the molecule of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms have been omitted for clarity.
	Fig. 2. A view of the molecule of (II). Displacement ellipsoids are drawn at the 30% probability level and H atoms have been omitted for clarity.

(I) cis-2-(4-tert-butylcyclohexyloxy)-1,3,5-trinitrobenzene

Crystal data

C16H21N3O7	Dx = 1.344 Mg m^−3
Mr = 367.36	Melting point = 382–385 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 15.257 (3) Å	Cell parameters from 25 reflections
b = 8.954 (2) Å	θ = 10–15°
c = 13.623 (2) Å	µ = 0.11 mm^−1
β = 102.71 (2)°	T = 130 K
V = 1815.5 (6) Å^3	Needle, brown
Z = 4	0.6 × 0.1 × 0.1 mm
F(000) = 776

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.071
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.7°
Graphite monochromator	h = −18→17
θ/2θ scans	k = −10→0
3341 measured reflections	l = 0→16
3191 independent reflections	3 standard reflections every 160 min
2589 reflections with I > 2σ(I)	intensity decay: 2%

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0547P)^2 + 0.7679P] where P = (Fo^2 + 2Fc^2)/3
3191 reflections	(Δ/σ)max = 0.001
232 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.21 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
O1	0.35406 (7)	0.10294 (13)	0.38706 (8)	0.0283 (3)
O2	0.42741 (9)	−0.11097 (14)	0.27609 (9)	0.0399 (3)
O3	0.52807 (8)	−0.01119 (14)	0.20653 (8)	0.0373 (3)
O4	0.76546 (9)	0.2442 (2)	0.44099 (13)	0.0684 (5)
O5	0.74124 (9)	0.32672 (17)	0.58197 (11)	0.0499 (4)
O6	0.38102 (12)	0.20593 (17)	0.60027 (12)	0.0608 (5)
O7	0.38321 (9)	0.41883 (14)	0.53021 (10)	0.0418 (3)
N1	0.48488 (9)	−0.01663 (16)	0.27262 (10)	0.0285 (3)
N2	0.71656 (10)	0.26895 (19)	0.49872 (13)	0.0415 (4)
N3	0.40736 (9)	0.29034 (15)	0.54415 (9)	0.0258 (3)
C1	0.29548 (11)	0.1294 (2)	0.28506 (11)	0.0289 (4)
H1	0.3302	0.1110	0.2319	0.035*
C2	0.26267 (12)	0.2886 (2)	0.27957 (13)	0.0334 (4)
H2A	0.2325	0.3115	0.2091	0.040*
H2B	0.3152	0.3559	0.2985	0.040*
C3	0.19776 (12)	0.3215 (2)	0.34719 (13)	0.0333 (4)
H3A	0.1727	0.4230	0.3323	0.040*
H3B	0.2311	0.3198	0.4183	0.040*
C4	0.12040 (11)	0.2088 (2)	0.33325 (12)	0.0298 (4)
H4	0.0876	0.2153	0.2612	0.036*
C5	0.16018 (11)	0.0509 (2)	0.34915 (12)	0.0309 (4)
H5A	0.1957	0.0413	0.4190	0.037*
H5B	0.1108	−0.0231	0.3396	0.037*
C6	0.22027 (11)	0.0175 (2)	0.27564 (13)	0.0324 (4)
H6A	0.2460	−0.0839	0.2889	0.039*
H6B	0.1836	0.0193	0.2060	0.039*
C7	0.05095 (12)	0.2445 (2)	0.39792 (14)	0.0391 (5)
C8	−0.03041 (15)	0.1422 (3)	0.3667 (2)	0.0672 (7)
H8A	−0.0113	0.0379	0.3776	0.101*
H8B	−0.0578	0.1579	0.2954	0.101*
H8C	−0.0744	0.1653	0.4072	0.101*
C9	0.01795 (11)	0.4061 (2)	0.37967 (11)	0.0538 (6)
H9A	0.0689	0.4745	0.3991	0.081*
H9B	−0.0264	0.4272	0.4200	0.081*
H9C	−0.0097	0.4198	0.3082	0.081*
C10	0.09208 (11)	0.2259 (2)	0.51114 (11)	0.0554 (6)
H10A	0.1443	0.2919	0.5306	0.083*
H10B	0.1110	0.1220	0.5250	0.083*
H10C	0.0472	0.2520	0.5498	0.083*
C11	0.44102 (10)	0.14076 (17)	0.40586 (11)	0.0225 (3)
C12	0.50619 (11)	0.09297 (17)	0.35444 (11)	0.0237 (3)
C13	0.59502 (11)	0.13768 (18)	0.38259 (12)	0.0271 (4)
H13	0.6373	0.1072	0.3448	0.033*
C14	0.62135 (11)	0.22707 (19)	0.46628 (12)	0.0284 (4)
C15	0.56138 (11)	0.27694 (18)	0.52143 (12)	0.0273 (4)
H15	0.5801	0.3381	0.5792	0.033*
C16	0.47322 (11)	0.23401 (17)	0.48883 (11)	0.0231 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0250 (6)	0.0421 (7)	0.0184 (5)	−0.0019 (5)	0.0063 (4)	0.0028 (5)
O2	0.0542 (8)	0.0341 (7)	0.0348 (7)	−0.0094 (6)	0.0168 (6)	−0.0092 (5)
O3	0.0471 (7)	0.0456 (8)	0.0247 (6)	0.0085 (6)	0.0198 (5)	0.0000 (5)
O4	0.0320 (8)	0.1101 (15)	0.0696 (11)	−0.0101 (9)	0.0251 (8)	−0.0115 (10)
O5	0.0396 (8)	0.0525 (9)	0.0531 (9)	−0.0117 (7)	0.0004 (6)	−0.0077 (7)
O6	0.0869 (12)	0.0511 (9)	0.0646 (10)	0.0316 (8)	0.0606 (9)	0.0297 (8)
O7	0.0448 (8)	0.0261 (7)	0.0593 (9)	0.0072 (6)	0.0221 (6)	−0.0016 (6)
N1	0.0356 (8)	0.0295 (8)	0.0223 (7)	0.0068 (7)	0.0103 (6)	0.0016 (6)
N2	0.0289 (8)	0.0471 (10)	0.0481 (10)	−0.0042 (7)	0.0077 (7)	0.0042 (8)
N3	0.0297 (7)	0.0281 (8)	0.0196 (7)	0.0033 (6)	0.0053 (5)	−0.0008 (6)
C1	0.0268 (8)	0.0438 (10)	0.0156 (7)	−0.0012 (8)	0.0039 (6)	0.0017 (7)
C2	0.0306 (9)	0.0398 (10)	0.0280 (9)	−0.0058 (8)	0.0022 (7)	0.0066 (8)
C3	0.0326 (9)	0.0332 (9)	0.0317 (9)	0.0002 (8)	0.0020 (7)	−0.0001 (8)
C4	0.0266 (8)	0.0409 (10)	0.0206 (8)	−0.0006 (8)	0.0024 (6)	−0.0003 (7)
C5	0.0293 (9)	0.0360 (10)	0.0278 (8)	−0.0064 (7)	0.0071 (7)	−0.0010 (7)
C6	0.0330 (9)	0.0369 (10)	0.0265 (8)	−0.0029 (8)	0.0050 (7)	−0.0050 (7)
C7	0.0340 (10)	0.0545 (12)	0.0303 (9)	0.0051 (9)	0.0105 (8)	−0.0008 (8)
C8	0.0391 (12)	0.094 (2)	0.0784 (17)	−0.0083 (12)	0.0346 (12)	−0.0186 (15)
C9	0.0496 (12)	0.0722 (16)	0.0396 (11)	0.0260 (11)	0.0098 (9)	0.0002 (10)
C10	0.0614 (14)	0.0788 (16)	0.0308 (10)	0.0217 (12)	0.0203 (10)	0.0088 (10)
C11	0.0260 (8)	0.0230 (8)	0.0189 (7)	0.0018 (6)	0.0063 (6)	0.0056 (6)
C12	0.0308 (8)	0.0223 (8)	0.0192 (7)	0.0025 (7)	0.0081 (6)	0.0033 (6)
C13	0.0302 (9)	0.0276 (9)	0.0267 (8)	0.0067 (7)	0.0129 (7)	0.0077 (7)
C14	0.0254 (8)	0.0301 (9)	0.0305 (9)	−0.0011 (7)	0.0080 (7)	0.0064 (7)
C15	0.0334 (9)	0.0246 (8)	0.0236 (8)	−0.0017 (7)	0.0058 (7)	0.0016 (6)
C16	0.0291 (8)	0.0218 (8)	0.0203 (8)	0.0039 (7)	0.0100 (6)	0.0042 (6)

Geometric parameters (Å, º)

O1—C11	1.3383 (19)	C5—H5A	0.9900
O1—C1	1.4964 (18)	C5—H5B	0.9900
O2—N1	1.2259 (18)	C6—H6A	0.9900
O3—N1	1.2281 (17)	C6—H6B	0.9900
O4—N2	1.217 (2)	C7—C8	1.526 (3)
O5—N2	1.228 (2)	C7—C9	1.534 (3)
O6—N3	1.2052 (19)	C7—C10	1.541 (2)
O7—N3	1.2103 (18)	C8—H8A	0.9800
N1—C12	1.467 (2)	C8—H8B	0.9800
N2—C14	1.471 (2)	C8—H8C	0.9800
N3—C16	1.471 (2)	C9—H9A	0.9800
C1—C6	1.507 (2)	C9—H9B	0.9800
C1—C2	1.508 (3)	C9—H9C	0.9800
C1—H1	1.0000	C10—H10A	0.9800
C2—C3	1.522 (2)	C10—H10B	0.9800
C2—H2A	0.9900	C10—H10C	0.9800
C2—H2B	0.9900	C11—C12	1.403 (2)
C3—C4	1.532 (2)	C11—C16	1.404 (2)
C3—H3A	0.9900	C12—C13	1.384 (2)
C3—H3B	0.9900	C13—C14	1.378 (2)
C4—C5	1.535 (3)	C13—H13	0.9500
C4—C7	1.553 (2)	C14—C15	1.380 (2)
C4—H4	1.0000	C15—C16	1.375 (2)
C5—C6	1.529 (2)	C15—H15	0.9500
C11—O1—C1	120.13 (11)	C5—C6—H6B	109.3
O2—N1—O3	124.01 (14)	H6A—C6—H6B	107.9
O2—N1—C12	118.20 (13)	C8—C7—C9	107.64 (17)
O3—N1—C12	117.74 (14)	C8—C7—C10	109.94 (17)
O4—N2—O5	124.49 (16)	C9—C7—C10	108.13 (15)
O4—N2—C14	117.69 (16)	C8—C7—C4	109.47 (16)
O5—N2—C14	117.83 (15)	C9—C7—C4	110.04 (15)
O6—N3—O7	124.27 (14)	C10—C7—C4	111.54 (14)
O6—N3—C16	118.07 (13)	C7—C8—H8A	109.5
O7—N3—C16	117.66 (13)	C7—C8—H8B	109.5
O1—C1—C6	105.18 (13)	H8A—C8—H8B	109.5
O1—C1—C2	108.65 (13)	C7—C8—H8C	109.5
C6—C1—C2	112.71 (14)	H8A—C8—H8C	109.5
O1—C1—H1	110.1	H8B—C8—H8C	109.5
C6—C1—H1	110.1	C7—C9—H9A	109.5
C2—C1—H1	110.1	C7—C9—H9B	109.5
C1—C2—C3	113.94 (14)	H9A—C9—H9B	109.5
C1—C2—H2A	108.8	C7—C9—H9C	109.5
C3—C2—H2A	108.8	H9A—C9—H9C	109.5
C1—C2—H2B	108.8	H9B—C9—H9C	109.5
C3—C2—H2B	108.8	C7—C10—H10A	109.5
H2A—C2—H2B	107.7	C7—C10—H10B	109.5
C2—C3—C4	112.56 (14)	H10A—C10—H10B	109.5
C2—C3—H3A	109.1	C7—C10—H10C	109.5
C4—C3—H3A	109.1	H10A—C10—H10C	109.5
C2—C3—H3B	109.1	H10B—C10—H10C	109.5
C4—C3—H3B	109.1	O1—C11—C12	127.51 (14)
H3A—C3—H3B	107.8	O1—C11—C16	117.45 (13)
C3—C4—C5	108.62 (14)	C12—C11—C16	114.98 (14)
C3—C4—C7	113.40 (15)	C13—C12—C11	122.12 (14)
C5—C4—C7	114.04 (14)	C13—C12—N1	116.36 (14)
C3—C4—H4	106.8	C11—C12—N1	121.36 (14)
C5—C4—H4	106.8	C14—C13—C12	119.12 (15)
C7—C4—H4	106.8	C14—C13—H13	120.4
C6—C5—C4	111.29 (14)	C12—C13—H13	120.4
C6—C5—H5A	109.4	C13—C14—C15	122.06 (15)
C4—C5—H5A	109.4	C13—C14—N2	119.03 (15)
C6—C5—H5B	109.4	C15—C14—N2	118.90 (15)
C4—C5—H5B	109.4	C16—C15—C14	116.89 (15)
H5A—C5—H5B	108.0	C16—C15—H15	121.6
C1—C6—C5	111.69 (14)	C14—C15—H15	121.6
C1—C6—H6A	109.3	C15—C16—C11	124.77 (14)
C5—C6—H6A	109.3	C15—C16—N3	117.93 (14)
C1—C6—H6B	109.3	C11—C16—N3	117.30 (13)
C11—O1—C1—C6	155.11 (14)	O2—N1—C12—C13	144.63 (15)
C11—O1—C1—C2	−83.98 (17)	O3—N1—C12—C13	−32.9 (2)
O1—C1—C2—C3	−67.89 (17)	O2—N1—C12—C11	−30.8 (2)
C6—C1—C2—C3	48.26 (19)	O3—N1—C12—C11	151.64 (14)
C1—C2—C3—C4	−50.75 (19)	C11—C12—C13—C14	2.7 (2)
C2—C3—C4—C5	54.79 (18)	N1—C12—C13—C14	−172.67 (14)
C2—C3—C4—C7	−177.32 (14)	C12—C13—C14—C15	−1.8 (2)
C3—C4—C5—C6	−58.41 (17)	C12—C13—C14—N2	177.30 (14)
C7—C4—C5—C6	174.06 (14)	O4—N2—C14—C13	12.2 (3)
O1—C1—C6—C5	66.86 (17)	O5—N2—C14—C13	−167.98 (16)
C2—C1—C6—C5	−51.34 (18)	O4—N2—C14—C15	−168.67 (17)
C4—C5—C6—C1	57.57 (18)	O5—N2—C14—C15	11.2 (2)
C3—C4—C7—C8	170.95 (18)	C13—C14—C15—C16	−0.3 (2)
C5—C4—C7—C8	−64.0 (2)	N2—C14—C15—C16	−179.46 (14)
C3—C4—C7—C9	52.85 (18)	C14—C15—C16—C11	1.8 (2)
C5—C4—C7—C9	177.87 (14)	C14—C15—C16—N3	−177.76 (14)
C3—C4—C7—C10	−67.1 (2)	O1—C11—C16—C15	176.52 (14)
C5—C4—C7—C10	57.9 (2)	C12—C11—C16—C15	−0.9 (2)
C1—O1—C11—C12	−56.7 (2)	O1—C11—C16—N3	−3.9 (2)
C1—O1—C11—C16	126.24 (15)	C12—C11—C16—N3	178.61 (13)
O1—C11—C12—C13	−178.53 (15)	O6—N3—C16—C15	−104.03 (19)
C16—C11—C12—C13	−1.4 (2)	O7—N3—C16—C15	75.94 (18)
O1—C11—C12—N1	−3.4 (2)	O6—N3—C16—C11	76.4 (2)
C16—C11—C12—N1	173.79 (13)	O7—N3—C16—C11	−103.64 (17)

(II) trans-2-(4-tert-butylcyclohexyloxy)-1,3,5-trinitrobenzene

Crystal data

C16H21N3O7	Dx = 1.375 Mg m^−3
Mr = 367.37	Melting point = 381–383 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 14.950 (3) Å	Cell parameters from 25 reflections
b = 8.349 (1) Å	θ = 10–15°
c = 14.292 (5) Å	µ = 0.11 mm^−1
β = 94.22 (3)°	T = 130 K
V = 1779.1 (7) Å^3	Slab, dark brown
Z = 4	0.50 × 0.25 × 0.10 mm
F(000) = 776

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.015
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.7°
Graphite monochromator	h = −17→17
θ/2θ scans	k = −9→0
3248 measured reflections	l = 0→16
3108 independent reflections	3 standard reflections every 160 min
2092 reflections with I > 2σ(I)	intensity decay: 2%

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.112	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0417P)^2 + 0.7612P] where P = (Fo^2 + 2Fc^2)/3
3104 reflections	(Δ/σ)max < 0.001
256 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.19 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
O1	0.84872 (10)	0.1190 (2)	0.40551 (11)	0.0253 (4)
O2	0.85703 (12)	0.4082 (2)	0.52717 (13)	0.0402 (5)
O3	0.90399 (12)	0.2361 (2)	0.63250 (12)	0.0359 (5)
O4	1.23900 (12)	0.3059 (2)	0.55036 (14)	0.0438 (5)
O5	1.26771 (13)	0.2012 (3)	0.41659 (16)	0.0602 (7)
O6	1.02665 (12)	−0.0020 (2)	0.20675 (11)	0.0369 (5)
O7	0.91774 (12)	−0.1046 (2)	0.27963 (12)	0.0339 (5)
N1	0.90506 (13)	0.2977 (2)	0.55517 (14)	0.0244 (5)
N2	1.21651 (14)	0.2425 (3)	0.47530 (17)	0.0361 (6)
N3	0.97976 (14)	−0.0092 (3)	0.27382 (14)	0.0282 (5)
C1	0.79426 (16)	0.1531 (3)	0.31599 (16)	0.0257 (6)
H1	0.8338	0.1464	0.2626	0.017 (6)*
C2	0.75570 (16)	0.3191 (3)	0.31971 (17)	0.0280 (6)
H2A	0.8048	0.3987	0.3264	0.035 (7)*
H2B	0.7194	0.3290	0.3746	0.034 (7)*
C3	0.69676 (16)	0.3517 (3)	0.22938 (18)	0.0316 (6)
H3A	0.7350	0.3539	0.1757	0.034 (7)*
H3B	0.6684	0.4583	0.2338	0.035 (7)*
C4	0.62307 (16)	0.2244 (3)	0.21108 (17)	0.0289 (6)
H4	0.5851	0.2287	0.2658	0.033 (7)*
C5	0.66574 (16)	0.0585 (3)	0.21249 (17)	0.0305 (6)
H5A	0.7038	0.0488	0.1590	0.043 (8)*
H5B	0.6179	−0.0234	0.2047	0.037 (7)*
C6	0.72289 (16)	0.0265 (3)	0.30392 (17)	0.0293 (6)
H6A	0.6847	0.0290	0.3576	0.033 (7)*
H6B	0.7509	−0.0807	0.3016	0.037 (7)*
C7	0.55888 (17)	0.2578 (4)	0.12176 (17)	0.0345 (7)
C8	0.6077 (2)	0.2401 (4)	0.03194 (18)	0.0443 (8)
H8A	0.6301	0.1303	0.0273	0.055 (9)*
H8B	0.6582	0.3152	0.0335	0.049 (9)*
H8C	0.5661	0.2635	−0.0226	0.051 (9)*
C9	0.4801 (2)	0.1405 (5)	0.1184 (2)	0.0572 (10)
H9A	0.5020	0.0317	0.1084	0.065 (11)*
H9B	0.4363	0.1698	0.0669	0.055 (9)*
H9C	0.4515	0.1449	0.1779	0.050 (9)*
C10	0.5215 (2)	0.4271 (4)	0.12585 (19)	0.0485 (9)
H10A	0.4964	0.4441	0.1865	0.054 (9)*
H10B	0.4743	0.4417	0.0753	0.045 (8)*
H10C	0.5697	0.5046	0.1184	0.065 (11)*
C11	0.93706 (16)	0.1490 (3)	0.41285 (16)	0.0228 (5)
C12	0.97072 (15)	0.2353 (3)	0.49202 (15)	0.0221 (5)
C13	1.05979 (16)	0.2654 (3)	0.51559 (16)	0.0251 (6)
H13	1.0791	0.3195	0.5719	0.025 (6)*
C14	1.12021 (16)	0.2127 (3)	0.45307 (17)	0.0258 (6)
C15	1.09264 (16)	0.1314 (3)	0.37222 (17)	0.0265 (6)
H15	1.1349	0.0993	0.3295	0.027 (7)*
C16	1.00252 (15)	0.0973 (3)	0.35411 (16)	0.0231 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0223 (9)	0.0320 (10)	0.0219 (9)	−0.0007 (7)	0.0036 (7)	0.0037 (7)
O2	0.0448 (12)	0.0381 (11)	0.0387 (11)	0.0200 (10)	0.0082 (9)	0.0031 (9)
O3	0.0447 (11)	0.0382 (11)	0.0264 (10)	0.0069 (9)	0.0141 (8)	0.0058 (9)
O4	0.0310 (11)	0.0466 (13)	0.0521 (13)	−0.0016 (9)	−0.0083 (9)	−0.0001 (10)
O5	0.0288 (11)	0.0772 (17)	0.0767 (16)	0.0004 (11)	0.0184 (11)	−0.0211 (13)
O6	0.0464 (12)	0.0420 (12)	0.0239 (10)	0.0104 (9)	0.0132 (8)	0.0007 (8)
O7	0.0341 (10)	0.0330 (11)	0.0348 (11)	−0.0008 (9)	0.0027 (8)	−0.0064 (8)
N1	0.0251 (11)	0.0231 (11)	0.0252 (12)	−0.0005 (9)	0.0035 (9)	−0.0019 (9)
N2	0.0284 (12)	0.0324 (13)	0.0473 (15)	0.0024 (11)	0.0017 (11)	0.0038 (12)
N3	0.0304 (12)	0.0296 (13)	0.0248 (12)	0.0080 (10)	0.0028 (9)	0.0008 (9)
C1	0.0258 (13)	0.0323 (15)	0.0188 (13)	0.0007 (11)	0.0012 (10)	0.0044 (11)
C2	0.0279 (14)	0.0288 (14)	0.0279 (14)	−0.0001 (12)	0.0059 (11)	0.0028 (11)
C3	0.0278 (14)	0.0357 (16)	0.0320 (15)	0.0063 (12)	0.0056 (11)	0.0069 (12)
C4	0.0224 (12)	0.0431 (16)	0.0222 (13)	0.0043 (12)	0.0072 (10)	0.0060 (12)
C5	0.0261 (14)	0.0366 (16)	0.0285 (14)	−0.0015 (12)	−0.0001 (11)	0.0017 (12)
C6	0.0293 (14)	0.0295 (15)	0.0285 (14)	−0.0025 (12)	−0.0012 (11)	0.0028 (12)
C7	0.0301 (14)	0.0503 (18)	0.0235 (13)	0.0086 (13)	0.0042 (11)	0.0067 (13)
C8	0.0487 (18)	0.060 (2)	0.0245 (14)	0.0151 (17)	0.0027 (13)	0.0029 (14)
C9	0.0393 (18)	0.088 (3)	0.0419 (19)	−0.0043 (19)	−0.0125 (15)	0.0149 (18)
C10	0.0417 (18)	0.075 (2)	0.0289 (16)	0.0276 (18)	0.0029 (13)	0.0072 (16)
C11	0.0275 (13)	0.0182 (13)	0.0229 (13)	0.0003 (10)	0.0026 (10)	0.0057 (10)
C12	0.0276 (13)	0.0193 (13)	0.0199 (12)	0.0020 (11)	0.0060 (10)	0.0045 (10)
C13	0.0310 (14)	0.0218 (13)	0.0224 (13)	0.0014 (11)	0.0007 (11)	0.0030 (11)
C14	0.0224 (13)	0.0224 (13)	0.0329 (14)	0.0016 (11)	0.0033 (11)	0.0082 (12)
C15	0.0293 (14)	0.0237 (14)	0.0274 (14)	0.0063 (11)	0.0094 (11)	0.0059 (11)
C16	0.0295 (13)	0.0201 (13)	0.0196 (12)	0.0030 (11)	0.0014 (10)	0.0027 (10)

Geometric parameters (Å, º)

O1—C11	1.341 (3)	C5—H5A	0.9900
O1—C1	1.492 (3)	C5—H5B	0.9900
O2—N1	1.218 (3)	C6—H6A	0.9900
O3—N1	1.220 (2)	C6—H6B	0.9900
O4—N2	1.221 (3)	C7—C10	1.523 (4)
O5—N2	1.226 (3)	C7—C9	1.530 (4)
O6—N3	1.230 (2)	C7—C8	1.530 (3)
O7—N3	1.230 (3)	C8—H8A	0.9800
N1—C12	1.476 (3)	C8—H8B	0.9800
N2—C14	1.472 (3)	C8—H8C	0.9800
N3—C16	1.472 (3)	C9—H9A	0.9800
C1—C6	1.503 (3)	C9—H9B	0.9800
C1—C2	1.504 (3)	C9—H9C	0.9800
C1—H1	1.0000	C10—H10A	0.9800
C2—C3	1.533 (3)	C10—H10B	0.9800
C2—H2A	0.9900	C10—H10C	0.9800
C2—H2B	0.9900	C11—C12	1.403 (3)
C3—C4	1.539 (4)	C11—C16	1.403 (3)
C3—H3A	0.9900	C12—C13	1.372 (3)
C3—H3B	0.9900	C13—C14	1.388 (3)
C4—C5	1.525 (4)	C13—H13	0.9500
C4—C7	1.565 (3)	C14—C15	1.377 (3)
C4—H4	1.0000	C15—C16	1.383 (3)
C5—C6	1.531 (3)	C15—H15	0.9500
C11—O1—C1	120.24 (17)	C5—C6—H6B	109.9
O2—N1—O3	124.7 (2)	H6A—C6—H6B	108.3
O2—N1—C12	117.9 (2)	C10—C7—C9	108.2 (2)
O3—N1—C12	117.30 (19)	C10—C7—C8	108.7 (2)
O4—N2—O5	125.3 (2)	C9—C7—C8	109.0 (2)
O4—N2—C14	117.7 (2)	C10—C7—C4	109.8 (2)
O5—N2—C14	117.0 (2)	C9—C7—C4	109.6 (2)
O7—N3—O6	124.1 (2)	C8—C7—C4	111.4 (2)
O7—N3—C16	118.09 (19)	C7—C8—H8A	109.5
O6—N3—C16	117.7 (2)	C7—C8—H8B	109.5
O1—C1—C6	107.60 (19)	H8A—C8—H8B	109.5
O1—C1—C2	109.37 (19)	C7—C8—H8C	109.5
C6—C1—C2	112.4 (2)	H8A—C8—H8C	109.5
O1—C1—H1	109.1	H8B—C8—H8C	109.5
C6—C1—H1	109.1	C7—C9—H9A	109.5
C2—C1—H1	109.1	C7—C9—H9B	109.5
C1—C2—C3	109.4 (2)	H9A—C9—H9B	109.5
C1—C2—H2A	109.8	C7—C9—H9C	109.5
C3—C2—H2A	109.8	H9A—C9—H9C	109.5
C1—C2—H2B	109.8	H9B—C9—H9C	109.5
C3—C2—H2B	109.8	C7—C10—H10A	109.5
H2A—C2—H2B	108.2	C7—C10—H10B	109.5
C2—C3—C4	112.4 (2)	H10A—C10—H10B	109.5
C2—C3—H3A	109.1	C7—C10—H10C	109.5
C4—C3—H3A	109.1	H10A—C10—H10C	109.5
C2—C3—H3B	109.1	H10B—C10—H10C	109.5
C4—C3—H3B	109.1	O1—C11—C12	116.9 (2)
H3A—C3—H3B	107.9	O1—C11—C16	128.5 (2)
C5—C4—C3	109.35 (19)	C12—C11—C16	114.6 (2)
C5—C4—C7	113.8 (2)	C13—C12—C11	125.1 (2)
C3—C4—C7	113.8 (2)	C13—C12—N1	117.5 (2)
C5—C4—H4	106.4	C11—C12—N1	117.3 (2)
C3—C4—H4	106.4	C12—C13—C14	116.7 (2)
C7—C4—H4	106.4	C12—C13—H13	121.6
C4—C5—C6	112.1 (2)	C14—C13—H13	121.6
C4—C5—H5A	109.2	C15—C14—C13	121.8 (2)
C6—C5—H5A	109.2	C15—C14—N2	119.5 (2)
C4—C5—H5B	109.2	C13—C14—N2	118.7 (2)
C6—C5—H5B	109.2	C14—C15—C16	119.1 (2)
H5A—C5—H5B	107.9	C14—C15—H15	120.5
C1—C6—C5	108.8 (2)	C16—C15—H15	120.5
C1—C6—H6A	109.9	C15—C16—C11	122.5 (2)
C5—C6—H6A	109.9	C15—C16—N3	115.9 (2)
C1—C6—H6B	109.9	C11—C16—N3	121.4 (2)
C11—O1—C1—C6	145.1 (2)	O2—N1—C12—C13	109.7 (2)
C11—O1—C1—C2	−92.5 (2)	O3—N1—C12—C13	−69.2 (3)
O1—C1—C2—C3	−177.80 (18)	O2—N1—C12—C11	−70.7 (3)
C6—C1—C2—C3	−58.3 (3)	O3—N1—C12—C11	110.4 (2)
C1—C2—C3—C4	55.3 (3)	C11—C12—C13—C14	3.5 (4)
C2—C3—C4—C5	−54.0 (3)	N1—C12—C13—C14	−176.9 (2)
C2—C3—C4—C7	177.5 (2)	C12—C13—C14—C15	−1.3 (4)
C3—C4—C5—C6	55.4 (3)	C12—C13—C14—N2	179.9 (2)
C7—C4—C5—C6	−176.1 (2)	O4—N2—C14—C15	−175.5 (2)
O1—C1—C6—C5	179.92 (19)	O5—N2—C14—C15	4.5 (3)
C2—C1—C6—C5	59.4 (3)	O4—N2—C14—C13	3.4 (3)
C4—C5—C6—C1	−57.9 (3)	O5—N2—C14—C13	−176.7 (2)
C5—C4—C7—C10	−178.7 (2)	C13—C14—C15—C16	−1.9 (4)
C3—C4—C7—C10	−52.5 (3)	N2—C14—C15—C16	176.9 (2)
C5—C4—C7—C9	62.6 (3)	C14—C15—C16—C11	3.1 (4)
C3—C4—C7—C9	−171.2 (2)	C14—C15—C16—N3	−171.6 (2)
C5—C4—C7—C8	−58.2 (3)	O1—C11—C16—C15	−177.1 (2)
C3—C4—C7—C8	68.0 (3)	C12—C11—C16—C15	−1.1 (3)
C1—O1—C11—C12	131.1 (2)	O1—C11—C16—N3	−2.7 (4)
C1—O1—C11—C16	−53.0 (3)	C12—C11—C16—N3	173.3 (2)
O1—C11—C12—C13	174.1 (2)	O7—N3—C16—C15	144.3 (2)
C16—C11—C12—C13	−2.4 (3)	O6—N3—C16—C15	−32.6 (3)
O1—C11—C12—N1	−5.4 (3)	O7—N3—C16—C11	−30.5 (3)
C16—C11—C12—N1	178.1 (2)	O6—N3—C16—C11	152.6 (2)