A series of three bis­[2-(methyl/tri­fluoro­methyl)-4H-3,1-benzoxazin-4-one] compounds

Each of the three title compounds, namely 6,6'-methyl­ene­bis­(2-methyl-4H-3,1-benz­oxazin-4-one), C₁₉H₁₄N₂O₄, 6,6'-methyl­ene­bis­(2-tri­fluoro­methyl-4H-3,1-benz­oxazin-4-one), C₁₉H₈F₃N₂O₄, and 6,6'-bi­(2-tri­fluoro­methyl-4H-3,1-benz­oxazin-4-one), C₁₈H₆F₆N₂O₄, contains two planar benz­ox­azin­one fragments. In the first two compounds, these planes are virtually perpendicular to each other, while the third compound is planar overall. The electronic effects of the substituent groups on the oxazine moiety result in distortion of the bond angles at the C atoms of the C=O and C=N bonds, and in redistribution of electronic density in the oxazine rings. The latter leads to different bond lengths within this ring in the three mol­ecules. All the mol­ecules form stacks in their crystals with distances of 3.2-3.6 Å between adjacent mol­ecules in a stack.

S1. Comment

Polyquinazolones (PQs, see scheme below) are an important class of polyheteroarylenes which possess high thermal and hydrolytic stability, and have good solubility in organic solvents. PQs are usually synthesized from diamines and bis[2-(alkyl/phenyl)-4H-3,1-benzoxazin-4-one] compounds.

Films obtained from PQs based on aromatic diamines have thermal, dielectric and physico-mechanical properties comparable with those of common polyimides. It was also shown that, as a rule, PQs have dielectric indices exceeding those of the famous DuPont `KAPTON' film (Odnoralova & Vasilyeva-Sokolova, 1978; Ponomarev et al., 1992; de Gaudemaris et al., 1965).

It is well known that when studying polymers, accurate knowledge of the molecular structure of the corresponding monomers is very important. For this reason, we undertook the current X-ray stuctural analysis of three 2-substituted bis-benzoxazinones, (I)–(III), which are of interest as PQ precursors.

The three molecules display symmetry. Each molecule of (III) has a crystallographic inversion center which coincides with the midpoint of the C6A—C6Aⁱ bond, whereas (I) and (II) each has a twofold axis passing through C11. The twofold symmetry is approximate (and non-crystallographic) in (I) but crystallographic in (II). Furthermore, bond angles at C11 are close to tetrahedral values in (I), but somewhat distorted in (II), where the C6A—C11—C6Aⁱ bond angle is 115.6 (4)°.

The benzoxazinone systems in all three molecules are planar, in agreement with earlier experimental data (Etter et al., 1982; Pink et al., 1993). Only in (III) does atom C10A of the trifluoromethyl group deviate from the oxazine plane, by 0.147 (2) Å. There appears to be no obvious way to rationalize this observation in terms of intramolecular interactions, since there are neither sterically bulky groups nor strong electronic ones in the molecule. Although not conclusive, the fact that the molecules form stacks suggests that intermolecular factors may be significant.

While bond lengths involving O3A and O3B are almost equal in (I), the values for O3A—C2A are much shorter than those for O3A—C4A in compounds (II) and (III). Moreover, in all three structures, the bond angles at C2A and C4A (or C4B) are distorted from their ideal values of 120°. These observations are probably best explained by the concerted electronic effects of adjacent substituents, namely the trifluoromethyl and carbonyl groups.

The planes of the benzoxazinone moieties in (I) are virtually perpendicular to each other, as shown by the dihedral angle of 82.42 (5)°; the corresponding angle in (II) is 74.79 (7)°.

Molecules of (III) are planar overall despite the presence of unfavorable short intramolecular H7A···H5A(−1 + x, −1 − y, −z) interactions of 2.12 (4) Å [the sum of the corrsesponding van der Waals radii is 2.32 Å (Zefirov & Zorkii, 1989)]. One F atom of each trifluoromethyl group in (II) and (III) lies in an approximately eclipsed conformation with respect to the adjacent C═N bond, as shown by the torsion angles N1A—C2A—C10A—F2A of −11.3 (5)° for (II) and N1A—C2A—C10A—F3A of 15.8 (3)° for (III).

Molecules of all three compounds form stacks, along the crystallographic a axis for (I) and along the b axis for (II) and (III), with the distance between successive molecules in the range 3.2–3.6 Å. However, in (I), only the benzoxazinone moieties where the atoms carry the suffix B (Fig. 1) form stacks; the moieties identified by the suffix A occupy the space between them. In (III), adjacent stacks are connected by weak intermolecular H7A···F3A'(2 − x,-1 − y,-z) interactions of 2.55 (3) Å [the sum of the corresponding van der Waals radii is 2.57 Å (Zefirov & Zorkii, 1989)].

S2. Experimental

The compounds studied were synthesized by analogous reactions of 5,5'-methylenebisanthranilic or 5,5'-bianthranilic acids (0.01 mol) with the corresponding anhydride (20 ml) [acetic anhydride for the preparation of (I) and hexafluoroacetic anhydride for the preparation of (II) and (III)] under reflux for 10 h. Crystals of the products suitable for X-ray structure determination were obtained after the reaction mixtures had been cooled and allowed to stand for several days.

S3. Refinement

All H atoms were found by difference Fourier syntheses. Methyl H atoms in (I) were refined as part of an idealized group which was allowed to rotate about the local C—C vector but not to deform or tip; the other H atoms were treated as riding [U_iso(H) = 1.2U_eq(C)] as were those of (II). The H atoms of (III) were refined isotropically.

Computing details

For all compounds, data collection: P3 (Siemens, 1989); cell refinement: P3; data reduction: XDISK (Siemens, 1989); program(s) used to solve structure: SHELXTL/PC (Sheldrick, 1994); program(s) used to refine structure: SHELXTL/PC; molecular graphics: SHELXTL/PC; software used to prepare material for publication: SHELXTL/PC.

Figures

	Fig. 1. A view of (I) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown with an arbitrary radius.
	Fig. 2. A view of (II) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown with an arbitrary radius. [Symmetry code: (i) −x, y, 1/2 − z.]
	Fig. 3. A view of (II) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown with an arbitrary radius. [Symmetry code: (i) 1 − x, −1 − y, −z.]

(I)

Crystal data

C19H14N2O4	Z = 2
Mr = 334.32	F(000) = 348
Triclinic, P1	Dx = 1.442 Mg m^−3
a = 7.162 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.2217 (15) Å	Cell parameters from 25 reflections
c = 13.807 (4) Å	θ = 10–12°
α = 98.10 (2)°	µ = 0.10 mm^−1
β = 99.40 (2)°	T = 293 K
γ = 102.51 (2)°	Needle, colorless
V = 769.8 (3) Å^3	0.50 × 0.20 × 0.20 mm

Data collection

Siemens P3/PC four-circle diffractometer	Rint = 0.015
Radiation source: fine-focus sealed tube	θmax = 25.1°, θmin = 1.5°
Graphite monochromator	h = 0→8
θ/2θ scans	k = −9→9
2964 measured reflections	l = −16→16
2722 independent reflections	2 standard reflections every 98 reflections
1399 reflections with I > 2σ(I)	intensity decay: 10%

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.098	H atoms treated by a mixture of independent and constrained refinement
S = 0.91	Calculated w = 1/[σ^2(Fo^2) + (0.0704P)^2] where P = (Fo^2 + 2Fc^2)/3
2710 reflections	(Δ/σ)max = −0.002
228 parameters	Δρmax = 0.16 e Å^−3
0 restraints	Δρmin = −0.17 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 on F² for ALL reflections except for 12 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
N1A	0.2785 (2)	0.1152 (2)	−0.03783 (11)	0.0388 (4)
C2A	0.2987 (3)	0.2245 (2)	0.03997 (14)	0.0380 (5)
O3A	0.4671 (2)	0.3512 (2)	0.08132 (9)	0.0420 (4)
C4A	0.6311 (3)	0.3676 (2)	0.03933 (13)	0.0386 (5)
C4'A	0.6121 (3)	0.2469 (2)	−0.05120 (12)	0.0340 (4)
C5A	0.7666 (3)	0.2536 (2)	−0.10200 (13)	0.0349 (4)
H5A	0.8810	0.3385	−0.07848	0.042*
C6A	0.7515 (3)	0.1368 (2)	−0.18601 (12)	0.0335 (4)
C7A	0.5770 (3)	0.0094 (2)	−0.21882 (13)	0.0395 (5)
H7A	0.5657	−0.0726	−0.27466	0.047*
C8A	0.4232 (3)	0.0028 (2)	−0.17069 (13)	0.0403 (5)
H8A	0.3089	−0.0819	−0.19476	0.048*
C8'A	0.4373 (3)	0.1219 (2)	−0.08633 (13)	0.0349 (4)
O9A	0.7717 (2)	0.4788 (2)	0.08058 (10)	0.0552 (4)
C1OA	0.1455 (3)	0.2377 (3)	0.09850 (15)	0.0490 (5)
H1OA	0.0354 (8)	0.1424 (9)	0.0737 (7)	0.073*
H1OB	0.1054 (14)	0.3405 (9)	0.0923 (8)	0.073*
H1OC	0.1962 (7)	0.2388 (17)	0.1675 (2)	0.073*
N1B	0.6716 (3)	0.3876 (2)	−0.60110 (12)	0.0536 (5)
C2B	0.6805 (3)	0.5438 (3)	−0.59615 (15)	0.0465 (5)
O3B	0.7530 (2)	0.6645 (2)	−0.51082 (10)	0.0547 (4)
C4B	0.8235 (3)	0.6214 (3)	−0.4205 (2)	0.0508 (6)
C4'B	0.8148 (3)	0.4437 (2)	−0.42310 (13)	0.0358 (4)
C5B	0.8783 (3)	0.3849 (2)	−0.33641 (13)	0.0376 (5)
H5B	0.9310	0.4614	−0.27683	0.045*
C6B	0.8634 (3)	0.2149 (2)	−0.33847 (13)	0.0351 (4)
C7B	0.7908 (3)	0.1057 (3)	−0.42995 (14)	0.0500 (6)
H7B	0.7833	−0.0094	−0.43311	0.060*
C8B	0.7301 (3)	0.1624 (3)	−0.51563 (15)	0.0573 (6)
H8B	0.6833	0.0862	−0.57569	0.069*
C8'B	0.7381 (3)	0.3322 (2)	−0.51306 (13)	0.0404 (5)
O9B	0.8838 (3)	0.7347 (2)	−0.34983 (12)	0.0819 (6)
C10B	0.6168 (3)	0.6227 (3)	−0.6821 (2)	0.0635 (7)
H10D	0.579 (2)	0.5389 (6)	−0.7422 (2)	0.095*
H10E	0.7223 (8)	0.7125 (13)	−0.6884 (7)	0.095*
H10F	0.5074 (15)	0.6678 (18)	−0.6713 (6)	0.095*
C11	0.9154 (3)	0.1472 (2)	−0.24356 (13)	0.0398 (5)
H11A	0.9382	0.0355	−0.26030	0.048*
H11B	1.0345	0.2213	−0.20233	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1A	0.0390 (10)	0.0359 (9)	0.0378 (9)	0.0030 (7)	0.0033 (8)	0.0098 (8)
C2A	0.0372 (12)	0.0363 (11)	0.0405 (11)	0.0068 (9)	0.0033 (9)	0.0151 (9)
O3A	0.0430 (8)	0.0390 (8)	0.0392 (7)	0.0048 (6)	0.0067 (6)	0.0014 (6)
C4A	0.0409 (12)	0.0348 (11)	0.0373 (10)	0.0045 (9)	0.0049 (9)	0.0078 (9)
C4'A	0.0402 (11)	0.0279 (9)	0.0305 (9)	0.0038 (8)	0.0011 (8)	0.0078 (8)
C5A	0.0359 (11)	0.0281 (10)	0.0365 (10)	0.0018 (8)	0.0006 (9)	0.0095 (8)
C6A	0.0381 (11)	0.0318 (10)	0.0304 (9)	0.0088 (8)	0.0005 (8)	0.0118 (8)
C7A	0.0500 (13)	0.0349 (11)	0.0292 (10)	0.0084 (9)	0.0007 (9)	0.0031 (8)
C8A	0.0411 (12)	0.0343 (11)	0.0374 (10)	0.0007 (9)	−0.0026 (9)	0.0052 (8)
C8'A	0.0347 (11)	0.0330 (11)	0.0340 (10)	0.0037 (9)	0.0004 (8)	0.0115 (8)
O9A	0.0509 (9)	0.0466 (8)	0.0506 (9)	−0.0098 (7)	0.0058 (7)	−0.0101 (7)
C1OA	0.0491 (13)	0.0498 (13)	0.0467 (12)	0.0080 (10)	0.0108 (10)	0.0094 (10)
N1B	0.0566 (12)	0.0553 (12)	0.0416 (10)	0.0019 (9)	−0.0028 (8)	0.0179 (8)
C2B	0.0398 (13)	0.0587 (15)	0.0446 (12)	0.0132 (10)	0.0097 (10)	0.0179 (11)
O3B	0.0771 (11)	0.0504 (9)	0.0515 (9)	0.0314 (8)	0.0211 (8)	0.0244 (7)
C4B	0.074 (2)	0.0450 (13)	0.0424 (12)	0.0233 (11)	0.0214 (11)	0.0131 (11)
C4'B	0.0380 (11)	0.0346 (10)	0.0382 (10)	0.0094 (8)	0.0140 (8)	0.0096 (8)
C5B	0.0430 (12)	0.0358 (11)	0.0323 (10)	0.0072 (9)	0.0072 (9)	0.0048 (8)
C6B	0.0360 (11)	0.0324 (10)	0.0368 (10)	0.0076 (8)	0.0074 (8)	0.0071 (8)
C7B	0.0691 (15)	0.0310 (10)	0.0443 (12)	0.0056 (10)	0.0040 (11)	0.0079 (9)
C8B	0.080 (2)	0.0400 (12)	0.0365 (11)	−0.0016 (12)	−0.0037 (11)	0.0005 (9)
C8'B	0.0412 (11)	0.0417 (11)	0.0359 (11)	0.0043 (9)	0.0049 (9)	0.0117 (9)
O9B	0.157 (2)	0.0431 (9)	0.0505 (10)	0.0353 (11)	0.0230 (11)	0.0066 (8)
C10B	0.0565 (15)	0.086 (2)	0.0611 (14)	0.0273 (13)	0.0132 (12)	0.0408 (13)
C11	0.0452 (12)	0.0352 (11)	0.0382 (10)	0.0103 (9)	0.0054 (9)	0.0075 (8)

Geometric parameters (Å, º)

N1A—C2A	1.266 (2)	N1B—C2B	1.264 (3)
N1A—C8'A	1.406 (2)	N1B—C8'B	1.404 (2)
C2A—O3A	1.389 (2)	C2B—O3B	1.375 (2)
C2A—C1OA	1.478 (3)	C2B—C10B	1.485 (3)
O3A—C4A	1.382 (2)	O3B—C4B	1.390 (2)
C4A—O9A	1.200 (2)	C4B—O9B	1.200 (2)
C4A—C4'A	1.450 (2)	C4B—C4'B	1.443 (3)
C4'A—C5A	1.399 (3)	C4'B—C8'B	1.387 (3)
C4'A—C8'A	1.401 (2)	C4'B—C5B	1.398 (3)
C5A—C6A	1.371 (2)	C5B—C6B	1.374 (3)
C6A—C7A	1.406 (3)	C6B—C7B	1.391 (3)
C6A—C11	1.516 (3)	C6B—C11	1.517 (2)
C7A—C8A	1.372 (3)	C7B—C8B	1.372 (3)
C8A—C8'A	1.387 (2)	C8B—C8'B	1.380 (3)
C2A—N1A—C8'A	118.0 (2)	N1B—C2B—O3B	124.7 (2)
N1A—C2A—O3A	124.7 (2)	N1B—C2B—C10B	124.7 (2)
N1A—C2A—C1OA	124.9 (2)	O3B—C2B—C10B	110.6 (2)
O3A—C2A—C1OA	110.3 (2)	C2B—O3B—C4B	121.2 (2)
C4A—O3A—C2A	121.58 (15)	O9B—C4B—O3B	116.8 (2)
O9A—C4A—O3A	117.4 (2)	O9B—C4B—C4'B	127.5 (2)
O9A—C4A—C4'A	127.3 (2)	O3B—C4B—C4'B	115.6 (2)
O3A—C4A—C4'A	115.3 (2)	C8'B—C4'B—C5B	120.7 (2)
C5A—C4'A—C8'A	120.5 (2)	C8'B—C4'B—C4B	118.5 (2)
C5A—C4'A—C4A	120.6 (2)	C5B—C4'B—C4B	120.8 (2)
C8'A—C4'A—C4A	118.9 (2)	C6B—C5B—C4'B	120.6 (2)
C6A—C5A—C4'A	120.8 (2)	C5B—C6B—C7B	117.8 (2)
C5A—C6A—C7A	118.0 (2)	C5B—C6B—C11	121.2 (2)
C5A—C6A—C11	121.1 (2)	C7B—C6B—C11	120.9 (2)
C7A—C6A—C11	120.9 (2)	C8B—C7B—C6B	122.0 (2)
C8A—C7A—C6A	121.8 (2)	C7B—C8B—C8'B	120.3 (2)
C7A—C8A—C8'A	120.3 (2)	C8B—C8'B—C4'B	118.5 (2)
C8A—C8'A—C4'A	118.5 (2)	C8B—C8'B—N1B	119.5 (2)
C8A—C8'A—N1A	120.0 (2)	C4'B—C8'B—N1B	122.0 (2)
C4'A—C8'A—N1A	121.5 (2)	C6A—C11—C6B	110.3 (2)
C2B—N1B—C8'B	117.9 (2)
C8'A—N1A—C2A—O3A	−0.1 (3)	N1B—C2B—O3B—C4B	−0.2 (3)
C8'A—N1A—C2A—C1OA	178.6 (2)	C10B—C2B—O3B—C4B	−179.4 (2)
N1A—C2A—O3A—C4A	−0.2 (3)	C2B—O3B—C4B—O9B	−179.9 (2)
C1OA—C2A—O3A—C4A	−179.1 (2)	C2B—O3B—C4B—C4'B	−0.1 (3)
C2A—O3A—C4A—O9A	−178.9 (2)	O9B—C4B—C4'B—C8'B	179.6 (2)
C2A—O3A—C4A—C4'A	1.5 (2)	O3B—C4B—C4'B—C8'B	−0.2 (3)
O9A—C4A—C4'A—C5A	−1.3 (3)	O9B—C4B—C4'B—C5B	1.0 (3)
O3A—C4A—C4'A—C5A	178.3 (2)	O3B—C4B—C4'B—C5B	−178.8 (2)
O9A—C4A—C4'A—C8'A	177.9 (2)	C8'B—C4'B—C5B—C6B	−0.9 (3)
O3A—C4A—C4'A—C8'A	−2.5 (2)	C4B—C4'B—C5B—C6B	177.7 (2)
C8'A—C4'A—C5A—C6A	−1.1 (3)	C4'B—C5B—C6B—C7B	2.5 (3)
C4A—C4'A—C5A—C6A	178.1 (2)	C4'B—C5B—C6B—C11	−174.8 (2)
C4'A—C5A—C6A—C7A	−0.6 (3)	C5B—C6B—C7B—C8B	−1.9 (3)
C4'A—C5A—C6A—C11	177.7 (2)	C11—C6B—C7B—C8B	175.4 (2)
C5A—C6A—C7A—C8A	1.7 (3)	C6B—C7B—C8B—C8'B	−0.5 (4)
C11—C6A—C7A—C8A	−176.7 (2)	C7B—C8B—C8'B—C4'B	2.2 (3)
C6A—C7A—C8A—C8'A	−1.0 (3)	C7B—C8B—C8'B—N1B	−178.7 (2)
C7A—C8A—C8'A—C4'A	−0.7 (3)	C5B—C4'B—C8'B—C8B	−1.5 (3)
C7A—C8A—C8'A—N1A	179.5 (2)	C4B—C4'B—C8'B—C8B	179.9 (2)
C5A—C4'A—C8'A—C8A	1.7 (3)	C5B—C4'B—C8'B—N1B	179.4 (2)
C4A—C4'A—C8'A—C8A	−177.4 (2)	C4B—C4'B—C8'B—N1B	0.8 (3)
C5A—C4'A—C8'A—N1A	−178.5 (2)	C2B—N1B—C8'B—C8B	179.8 (2)
C4A—C4'A—C8'A—N1A	2.4 (2)	C2B—N1B—C8'B—C4'B	−1.1 (3)
C2A—N1A—C8'A—C8A	178.8 (2)	C5A—C6A—C11—C6B	−104.1 (2)
C2A—N1A—C8'A—C4'A	−1.0 (2)	C7A—C6A—C11—C6B	74.2 (2)
C8'B—N1B—C2B—O3B	0.8 (3)	C5B—C6B—C11—C6A	78.1 (2)
C8'B—N1B—C2B—C10B	179.9 (2)	C7B—C6B—C11—C6A	−99.1 (2)

(II)

Crystal data

C19H8F6N2O4	F(000) = 888
Mr = 442.28	Dx = 1.685 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 25.643 (17) Å	Cell parameters from 24 reflections
b = 5.206 (2) Å	θ = 10–12°
c = 16.211 (10) Å	µ = 0.16 mm^−1
β = 126.35 (4)°	T = 293 K
V = 1743.0 (17) Å^3	Parallelepiped, colorless
Z = 4	0.40 × 0.30 × 0.30 mm

Data collection

Siemens P3/PC four-circle diffractometer	Rint = 0.116
Radiation source: fine-focus sealed tube	θmax = 30°, θmin = 2.0°
Graphite monochromator	h = 0→36
θ/2θ scans	k = 0→7
2596 measured reflections	l = −22→18
2544 independent reflections	2 standard reflections every 98 reflections
1468 reflections with I > 2σ(I)	intensity decay: 10%

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)] = 0.081	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.209	H-atom parameters constrained
S = 1.05	Calculated w = 1/[σ^2(Fo^2) + (0.1162P)^2 + 2.6524P] where P = (Fo^2 + 2Fc^2)/3
2492 reflections	(Δ/σ)max < 0.001
145 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.39 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 on F² for ALL reflections except for 52 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
N1A	0.15830 (13)	0.2895 (6)	0.1743 (2)	0.0458 (7)
C2A	0.15921 (15)	0.2129 (7)	0.1014 (2)	0.0451 (8)
O3A	0.12640 (12)	0.0153 (5)	0.0367 (2)	0.0520 (6)
C4A	0.0860 (2)	−0.1394 (7)	0.0473 (2)	0.0428 (7)
C4'A	0.08236 (14)	−0.0605 (6)	0.1302 (2)	0.0370 (6)
C5A	0.0432 (2)	−0.1980 (6)	0.1483 (2)	0.0401 (7)
H5A	0.0193	−0.3373	0.1069	0.040 (9)*
C6A	0.0401 (2)	−0.1271 (6)	0.2275 (2)	0.0414 (7)
C7A	0.0771 (2)	0.0826 (6)	0.2883 (2)	0.0447 (7)
H7A	0.0757	0.1305	0.3422	0.050 (10)*
C8A	0.1154 (2)	0.2200 (7)	0.2709 (2)	0.0460 (8)
H8A	0.1392	0.3599	0.3120	0.055 (10)*
C8'A	0.11819 (14)	0.1478 (6)	0.1911 (2)	0.0399 (7)
O9A	0.05947 (14)	−0.3129 (6)	−0.0111 (2)	0.0590 (7)
C10A	0.2014 (2)	0.3414 (9)	0.0769 (3)	0.0627 (11)
C11	0.0000	−0.2819 (10)	0.2500	0.0507 (12)
H11A	0.0320	−0.3867	0.3100	0.056 (11)*
F1A	0.2491 (2)	0.1908 (8)	0.1011 (3)	0.1246 (15)
F2A	0.2255 (2)	0.5580 (7)	0.1266 (3)	0.1020 (11)
F3A	0.16879 (14)	0.3956 (7)	−0.0205 (2)	0.0924 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1A	0.0412 (14)	0.060 (2)	0.0448 (14)	−0.0062 (12)	0.0302 (12)	−0.0014 (12)
C2A	0.039 (2)	0.063 (2)	0.043 (2)	−0.0001 (15)	0.0291 (14)	0.0029 (15)
O3A	0.0573 (13)	0.069 (2)	0.0513 (13)	−0.0083 (12)	0.0443 (12)	−0.0085 (12)
C4A	0.045 (2)	0.056 (2)	0.041 (2)	0.0027 (14)	0.0323 (14)	0.0006 (14)
C4'A	0.0398 (14)	0.046 (2)	0.0349 (13)	0.0032 (13)	0.0276 (12)	−0.0003 (12)
C5A	0.045 (2)	0.043 (2)	0.045 (2)	−0.0010 (13)	0.0337 (14)	−0.0039 (13)
C6A	0.051 (2)	0.045 (2)	0.048 (2)	0.0055 (14)	0.0398 (15)	0.0053 (13)
C7A	0.059 (2)	0.050 (2)	0.043 (2)	0.002 (2)	0.039 (2)	−0.0022 (14)
C8A	0.054 (2)	0.054 (2)	0.041 (2)	−0.004 (2)	0.0341 (15)	−0.0068 (14)
C8'A	0.041 (2)	0.050 (2)	0.0388 (14)	0.0017 (13)	0.0291 (13)	0.0024 (13)
O9A	0.072 (2)	0.071 (2)	0.0542 (14)	−0.0114 (14)	0.0490 (14)	−0.0184 (13)
C10A	0.060 (2)	0.079 (3)	0.072 (2)	−0.007 (2)	0.052 (2)	0.005 (2)
C11	0.070 (3)	0.047 (3)	0.070 (3)	0.000	0.060 (3)	0.000
F1A	0.094 (2)	0.142 (3)	0.200 (4)	0.046 (2)	0.122 (3)	0.070 (3)
F2A	0.103 (2)	0.125 (3)	0.111 (2)	−0.051 (2)	0.081 (2)	−0.024 (2)
F3A	0.095 (2)	0.135 (3)	0.072 (2)	−0.020 (2)	0.063 (2)	0.014 (2)

Geometric parameters (Å, º)

N1A—C2A	1.260 (4)	C5A—C6A	1.384 (4)
N1A—C8'A	1.418 (4)	C6A—C7A	1.398 (5)
C2A—O3A	1.349 (4)	C6A—C11	1.512 (4)
C2A—C10A	1.512 (5)	C7A—C8A	1.373 (5)
O3A—C4A	1.401 (4)	C8A—C8'A	1.389 (4)
C4A—O9A	1.188 (4)	C10A—F1A	1.303 (5)
C4A—C4'A	1.461 (4)	C10A—F3A	1.307 (5)
C4'A—C8'A	1.385 (4)	C10A—F2A	1.309 (5)
C4'A—C5A	1.397 (4)	C11—C6A^i	1.512 (4)
C2A—N1A—C8'A	115.7 (3)	C7A—C6A—C11	121.4 (2)
N1A—C2A—O3A	128.4 (3)	C8A—C7A—C6A	122.1 (3)
N1A—C2A—C10A	121.3 (3)	C7A—C8A—C8'A	119.2 (3)
O3A—C2A—C10A	110.3 (3)	C4'A—C8'A—C8A	119.8 (3)
C2A—O3A—C4A	120.5 (2)	C4'A—C8'A—N1A	121.4 (2)
O9A—C4A—O3A	117.1 (2)	C8A—C8'A—N1A	118.8 (3)
O9A—C4A—C4'A	128.9 (3)	F1A—C10A—F3A	107.9 (4)
O3A—C4A—C4'A	114.0 (3)	F1A—C10A—F2A	108.4 (4)
C8'A—C4'A—C5A	120.5 (2)	F3A—C10A—F2A	106.8 (4)
C8'A—C4'A—C4A	119.9 (3)	F1A—C10A—C2A	110.2 (3)
C5A—C4'A—C4A	119.6 (3)	F3A—C10A—C2A	111.6 (3)
C6A—C5A—C4'A	120.1 (3)	F2A—C10A—C2A	111.7 (3)
C5A—C6A—C7A	118.3 (3)	C6A^i—C11—C6A	115.6 (4)
C5A—C6A—C11	120.2 (3)
C8'A—N1A—C2A—O3A	0.8 (5)	C5A—C4'A—C8'A—C8A	0.2 (5)
C8'A—N1A—C2A—C10A	−178.2 (3)	C4A—C4'A—C8'A—C8A	−179.1 (3)
N1A—C2A—O3A—C4A	−1.6 (5)	C5A—C4'A—C8'A—N1A	179.9 (3)
C10A—C2A—O3A—C4A	177.5 (3)	C4A—C4'A—C8'A—N1A	0.6 (4)
C2A—O3A—C4A—O9A	−178.6 (3)	C7A—C8A—C8'A—C4'A	0.2 (5)
C2A—O3A—C4A—C4'A	1.6 (4)	C7A—C8A—C8'A—N1A	−179.5 (3)
O9A—C4A—C4'A—C8'A	179.1 (3)	C2A—N1A—C8'A—C4'A	−0.3 (4)
O3A—C4A—C4'A—C8'A	−1.2 (4)	C2A—N1A—C8'A—C8A	179.3 (3)
O9A—C4A—C4'A—C5A	−0.2 (5)	N1A—C2A—C10A—F1A	109.3 (5)
O3A—C4A—C4'A—C5A	179.5 (3)	O3A—C2A—C10A—F1A	−69.9 (5)
C8'A—C4'A—C5A—C6A	−0.2 (5)	N1A—C2A—C10A—F3A	−130.8 (4)
C4A—C4'A—C5A—C6A	179.1 (3)	O3A—C2A—C10A—F3A	50.0 (4)
C4'A—C5A—C6A—C7A	−0.3 (5)	N1A—C2A—C10A—F2A	−11.3 (5)
C4'A—C5A—C6A—C11	−177.5 (3)	O3A—C2A—C10A—F2A	169.5 (3)
C5A—C6A—C7A—C8A	0.7 (5)	C5A—C6A—C11—C6A^i	−137.0 (3)
C11—C6A—C7A—C8A	177.9 (3)	C7A—C6A—C11—C6A^i	45.8 (3)
C6A—C7A—C8A—C8'A	−0.7 (5)

Symmetry code: (i) −x, y, −z+1/2.

(III)

Crystal data

C18H6F6N2O4	F(000) = 428
Mr = 428.24	Dx = 1.761 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 10.509 (2) Å	Cell parameters from 24 reflections
b = 5.0144 (7) Å	θ = 10–12°
c = 15.397 (3) Å	µ = 0.17 mm^−1
β = 95.35 (2)°	T = 293 K
V = 807.8 (3) Å^3	Parallelepiped, yellow
Z = 2	0.50 × 0.30 × 0.30 mm

Data collection

Siemens P3/PC four-circle diffractometer	Rint = 0.016
Radiation source: fine-focus sealed tube	θmax = 28.1°, θmin = 2.3°
Graphite monochromator	h = 0→13
θ/2θ scans	k = 0→6
2066 measured reflections	l = −20→20
1962 independent reflections	2 standard reflections every 98 reflections
1357 reflections with I > 2σ(I)	intensity decay: 10%

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)] = 0.049	Hydrogen site location: difference Fourier map
wR(F^2) = 0.146	All H-atom parameters refined
S = 1.08	Calculated w = 1/[σ^2(Fo^2) + (0.1023P)^2] where P = (Fo^2 + 2Fc^2)/3
1939 reflections	(Δ/σ)max < 0.001
148 parameters	Δρmax = 0.37 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 on F² for ALL reflections except for 23 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
N1A	0.94263 (13)	−0.2078 (3)	0.09563 (9)	0.0397 (4)
C2A	0.9540 (2)	−0.0248 (3)	0.15143 (10)	0.0366 (4)
O3A	0.86126 (11)	0.1148 (2)	0.18660 (7)	0.0381 (3)
C4A	0.7336 (2)	0.0453 (3)	0.16633 (10)	0.0351 (4)
C4'A	0.71245 (15)	−0.1684 (3)	0.10170 (9)	0.0319 (4)
C5A	0.5885 (2)	−0.2514 (3)	0.07554 (10)	0.0344 (4)
H5A	0.526 (3)	−0.155 (5)	0.0972 (15)	0.064 (7)*
C6A	0.56587 (15)	−0.4533 (3)	0.01389 (9)	0.0317 (4)
C7A	0.6731 (2)	−0.5683 (4)	−0.01966 (11)	0.0399 (4)
H7A	0.665 (3)	−0.726 (6)	−0.0604 (15)	0.070 (7)*
C8A	0.7959 (2)	−0.4881 (4)	0.00610 (11)	0.0408 (4)
H8A	0.862 (2)	−0.567 (5)	−0.0157 (15)	0.061 (7)*
C8'A	0.81761 (15)	−0.2859 (3)	0.06767 (9)	0.0338 (4)
O9A	0.65575 (13)	0.1649 (3)	0.20142 (8)	0.0485 (4)
C10A	1.0851 (2)	0.0625 (4)	0.19104 (12)	0.0471 (5)
F1A	1.10760 (14)	−0.0313 (4)	0.26994 (9)	0.0932 (6)
F2A	1.0949 (2)	0.3222 (3)	0.19591 (15)	0.1055 (7)
F3A	1.17600 (13)	−0.0231 (4)	0.14582 (10)	0.0886 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1A	0.0313 (7)	0.0503 (8)	0.0373 (7)	−0.0010 (6)	0.0023 (6)	−0.0054 (6)
C2A	0.0328 (8)	0.0412 (9)	0.0352 (8)	−0.0006 (7)	−0.0001 (6)	0.0035 (7)
O3A	0.0363 (7)	0.0365 (6)	0.0406 (6)	−0.0018 (5)	−0.0008 (5)	−0.0044 (5)
C4A	0.0346 (8)	0.0345 (8)	0.0360 (8)	0.0007 (6)	0.0008 (6)	−0.0012 (6)
C4'A	0.0324 (8)	0.0331 (8)	0.0299 (7)	0.0018 (6)	0.0017 (6)	−0.0001 (6)
C5A	0.0306 (8)	0.0371 (8)	0.0358 (8)	0.0033 (7)	0.0040 (6)	−0.0034 (6)
C6A	0.0310 (8)	0.0374 (8)	0.0265 (7)	0.0012 (6)	0.0009 (6)	0.0013 (6)
C7A	0.0351 (8)	0.0505 (10)	0.0340 (8)	0.0005 (7)	0.0024 (6)	−0.0127 (7)
C8A	0.0318 (8)	0.0532 (10)	0.0378 (8)	0.0045 (7)	0.0059 (7)	−0.0099 (7)
C8'A	0.0299 (8)	0.0416 (8)	0.0300 (7)	0.0005 (6)	0.0027 (6)	0.0002 (6)
O9A	0.0426 (7)	0.0482 (8)	0.0545 (8)	0.0044 (5)	0.0028 (6)	−0.0185 (6)
C10A	0.0394 (10)	0.0516 (11)	0.0496 (10)	−0.0051 (8)	0.0005 (8)	−0.0079 (8)
F1A	0.0608 (9)	0.156 (2)	0.0573 (8)	−0.0253 (10)	−0.0230 (7)	0.0189 (9)
F2A	0.0592 (9)	0.0572 (9)	0.194 (2)	−0.0155 (7)	−0.0220 (11)	−0.0185 (10)
F3A	0.0356 (7)	0.1348 (15)	0.0963 (10)	−0.0103 (7)	0.0103 (7)	−0.0497 (10)

Geometric parameters (Å, º)

N1A—C2A	1.255 (2)	C5A—C6A	1.393 (2)
N1A—C8'A	1.400 (2)	C6A—C7A	1.407 (2)
C2A—O3A	1.353 (2)	C6A—C6A^i	1.486 (3)
C2A—C10A	1.519 (2)	C7A—C8A	1.374 (3)
O3A—C4A	1.393 (2)	C8A—C8'A	1.392 (2)
C4A—O9A	1.185 (2)	C10A—F1A	1.304 (2)
C4A—C4'A	1.465 (2)	C10A—F3A	1.306 (2)
C4'A—C5A	1.391 (2)	C10A—F2A	1.308 (3)
C4'A—C8'A	1.397 (2)
C2A—N1A—C8'A	116.21 (14)	C5A—C6A—C6A^i	121.3 (2)
N1A—C2A—O3A	128.8 (2)	C7A—C6A—C6A^i	121.5 (2)
N1A—C2A—C10A	120.7 (2)	C8A—C7A—C6A	122.5 (2)
O3A—C2A—C10A	110.51 (14)	C7A—C8A—C8'A	119.9 (2)
C2A—O3A—C4A	119.66 (13)	C8A—C8'A—C4'A	118.53 (15)
O9A—C4A—O3A	117.57 (14)	C8A—C8'A—N1A	120.16 (14)
O9A—C4A—C4'A	127.7 (2)	C4'A—C8'A—N1A	121.30 (14)
O3A—C4A—C4'A	114.68 (13)	F1A—C10A—F3A	107.5 (2)
C5A—C4'A—C8'A	121.17 (14)	F1A—C10A—F2A	107.4 (2)
C5A—C4'A—C4A	119.63 (14)	F3A—C10A—F2A	107.5 (2)
C8'A—C4'A—C4A	119.19 (14)	F1A—C10A—C2A	110.4 (2)
C4'A—C5A—C6A	120.70 (15)	F3A—C10A—C2A	111.9 (2)
C5A—C6A—C7A	117.15 (15)	F2A—C10A—C2A	111.9 (2)
C8'A—N1A—C2A—O3A	−2.4 (3)	C6A—C7A—C8A—C8'A	0.0 (3)
C8'A—N1A—C2A—C10A	175.72 (15)	C7A—C8A—C8'A—C4'A	−0.2 (3)
N1A—C2A—O3A—C4A	5.3 (3)	C7A—C8A—C8'A—N1A	178.5 (2)
C10A—C2A—O3A—C4A	−172.93 (14)	C5A—C4'A—C8'A—C8A	0.4 (2)
C2A—O3A—C4A—O9A	176.77 (15)	C4A—C4'A—C8'A—C8A	−179.79 (14)
C2A—O3A—C4A—C4'A	−4.2 (2)	C5A—C4'A—C8'A—N1A	−178.23 (14)
O9A—C4A—C4'A—C5A	−0.2 (3)	C4A—C4'A—C8'A—N1A	1.6 (2)
O3A—C4A—C4'A—C5A	−179.05 (13)	C2A—N1A—C8'A—C8A	−179.78 (15)
O9A—C4A—C4'A—C8'A	−180.0 (2)	C2A—N1A—C8'A—C4'A	−1.2 (2)
O3A—C4A—C4'A—C8'A	1.2 (2)	N1A—C2A—C10A—F1A	−103.9 (2)
C8'A—C4'A—C5A—C6A	−0.5 (2)	O3A—C2A—C10A—F1A	74.5 (2)
C4A—C4'A—C5A—C6A	179.69 (14)	N1A—C2A—C10A—F3A	15.8 (3)
C4'A—C5A—C6A—C7A	0.3 (2)	O3A—C2A—C10A—F3A	−165.8 (2)
C4'A—C5A—C6A—C6A^i	179.2 (2)	N1A—C2A—C10A—F2A	136.5 (2)
C5A—C6A—C7A—C8A	−0.1 (3)	O3A—C2A—C10A—F2A	−45.1 (2)
C6A^i—C6A—C7A—C8A	−178.9 (2)

Symmetry code: (i) −x+1, −y−1, −z.