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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Volume 61| Part 6| June 2005| Pages o369-o372
doi:10.1107/S0108270105010218

The (1RS,2RS,7RS,8RS)- and (1RS,2SR,7SR,8RS)-diastereoisomers of 8,9,11,12-tetra­chloro-N-ethyl­tri­cyclo­[6.2.2.02,7]dodeca-9,11-diene-1,10-dicarboximide

CROSSMARK_Color_square_no_text.svg
Fionuala M. Grimley,a Cormac O'Donnell,a Albert C. Pratt,a Conor Longa and R. Alan Howieb*

aSchool of Chemical Sciences, Dublin City University, Dublin 9, Ireland, and bDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
*Correspondence e-mail: r.a.howie@abdn.ac.uk

(Received 22 March 2005; accepted 31 March 2005; online 13 May 2005)

Two racemic diastereoisomers, C16H15Cl4NO2, of the title 1,4-photoadduct of N-ethyl­tetra­chloro­phthalimide with cyclo­hexene have been isolated and their stereostructures ­determined.

Comment

The photochemistry of phthalimides has been studied extensively and has been reviewed by Kanaoka (1978[Kanaoka, Y. (1978). Acc. Chem. Res. 11, 407-413.]), Coyle (1984[Coyle, J. D. (1984). Synthetic Organic Photochemistry, edited by W. M. Horspool, pp. 259-284. New York: Plenum Press.]) and Oelgemöller & Griesbeck (2002[Oelgemöller, M. & Griesbeck, A. G. (2002). J. Photochem. Photobiol. C, 3, 109-127.]). Schwack (1987[Schwack, W. (1987). Tetrahedron Lett. 28, 1869-1871.]), Suau et al. (1989[Suau, R., Garcia-Segura, R. & Sosa-Olaya, F. (1989). Tetrahedron Lett. 30, 3225-3228.]) and Kubo et al. (1989[Kubo, Y., Taniguchi, E. & Araki, T. (1989). Heterocycles, 29, 1857-1860.]) have all reported the photoinduced para-cyclo­addition of alkenes to various N-substituted phthalimides to yield products analogous to the title compounds. However, the spectroscopic methods used for product structure elucidation left the precise product stereochemistries unresolved. The stereochemistries of two related diastereomeric 1,4-cyclo­adducts, (I)[link] and (II)[link], formed by photoreaction of N-eth­yl-3,4,5,6-tetra­chloro­phthalimide with cyclo­hexene, are reported here.

[Scheme 1]

Fig. 1[link] shows the (1R,2R,7R,8R)-enantiomer of the major photoadduct, (I)[link], isolated from irradiation of N-ethyl­tetra­chloro­phthalimide in the presence of cyclo­hexene. The (1R,2S,7S,8R)-enantiomer of the minor photoadduct, (II)[link], is shown in Fig. 2[link]. Corresponding bond lengths and angles for (I)[link] and (II)[link] are generally similar, and most have values that are typical of their types. Exceptions include the C9—C10—C14 angles of 135.5 (3) and 135.0 (2)° for (I)[link] and (II)[link], respectively. Also notable are the Cl1—C8 bonds of 1.768 (3) and 1.770 (2) Å in (I)[link] and (II)[link], respectively; these are significantly longer than the remaining C—Cl bonds, which range from 1.704 (2) to 1.714 (4) Å. While the distances to atoms Cl3 and Cl4 are typical of those in Cl—C=C—Cl fragments, those to Cl2 are short for their type (mean value 1.734 Å; Allen et al., 1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). Those to Cl1, on the other hand, are typical of Cl—C(C)2—C(C)2—Cl bonds, but are much shorter than isolated Cl—C(C)3 bonds.

From Figs. 1[link] and 2[link] it is clear that the difference between the isomers is the disposition of the H atoms at the stereogenic centres at C2 and C7. The torsion angles given in Table 3[link] confirm this. Also present in Table 3[link] are the corresponding values for N-benzoyl­tricyclo­dodeca­dienedicarboximide, (III)[link], in the same enantiomeric form as (I)[link] and (II)[link], whose structure has been described by McSweeney et al. (2005[McSweeney, N., Pratt, A. C., Long, C. & Howie, R. A. (2005). Acta Cryst. E61, o547-o549.]). Adduct (III)[link], which is formed as a single diastereoisomer by the photoaddition of cyclo­hexene to N-benzoyl­phthalimide, is wholly analogous to (I)[link] and (II)[link], apart from the N-substituent and the absence of Cl atoms. The crystals of (I)[link], (II)[link] and (III)[link] are all alike in being racemic with enantiomers that differ in the configurations at C1 and C8 in the product mol­ecules. These differences arise because there are two equally probable choices for the 1,4-atom pair of the parent phthalimide at which addition to the cyclo­hexene can take place. The data in Table 3[link] correspond, therefore, for (I)[link] and (II)[link] to the mol­ecule selected as the asymmetric unit, but for (III)[link] to the enantiomer of the mol­ecule selected as the asymmetric unit of the structure as described by McSweeney et al. (2005[McSweeney, N., Pratt, A. C., Long, C. & Howie, R. A. (2005). Acta Cryst. E61, o547-o549.]). The torsion angles about the C1—C2 and C7—C8 bonds clearly show the structural difference between diastereoisomers (I)[link] and (II)[link]. These values also show that the isomeric form of (III)[link] is the same as that of (I)[link] and different from that of (II)[link]. The stereochemical relationship between (I)[link] and (II)[link] is also evident in the puckering parameters (Cremer & Pople, 1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]) associated with the cyclo­hexane ring defined by atoms C2–C7. The parameters, with those for (II)[link] in square brackets, are Q = 0.575 (4) Å [0.628 (3) Å], θ = 13.1 (4)° [166.6 (3)°] and φ = 337.3 (16)° [151.6 (11)°]. In terms of θ and φ, these are related as required for inversion of the conformation of the ring consistent with the different configurations at C2 and C7 for the two diastereoisomers.

The packing of the mol­ecules of (I)[link] creates layers parallel to (100) and, for the choice of origin used in the refinement, centred on x = 0 (Fig. 3[link]), within which the C6—H6⋯O2 hydrogen bonds (Table 1[link]) create centrosymmetric dimers, such as that shown in the centre of the cell. Further short contacts [Cl3⋯O2iii; symmetry code: (iii) −x + 1, y − [{1\over 2}], −z + [{1\over 2}]] are found between the dimers and within the layer of mol­ecules. In (II)[link], the mol­ecules are found in layers parallel to ([\overline 1]02), inter­connected as shown in Fig. 4[link] by the hydrogen bonds given in Table 2[link].

The racemic nature of (III)[link] and of the isomers (I)[link] and (II)[link], a prerequisite for the refinement of the structures in centrosymmetric space groups, is a natural consequence of the manner in which the compounds have been formed by para-cyclo­addition of achiral reactants. There are four possible racemic products, viz. two involving trans ring junctions across the C2—C7 bond and two involving cis junctions across the C2—C7 bond arising from 1,4-addition across the aromatic ring, which must of necessity be cis. Formation of a single unsymmetrical diastereoisomer from N-benzoyl­phthalimide suggests a favoured approach by the cyclo­hexene to the excited phthalimide, possibly involving minimization, in the transition state, of steric inter­actions between the N-benzo­ylimide ring and the cyclo­hexene. For N-ethyl­tetra­chloro­phthalimide, on the other hand, two diastereoisomers are formed, presumably reflecting lesser differentiation between the reaction pathways arising from the presence of the Cl atoms and the sterically less demanding eth­yl group. The stereochemistry at the C2—C7 ring junction in both cases is the outcome of overall trans addition across the cyclo­hexene double bond.

[Figure 1]
Figure 1
The mol­ecule of (I)[link]. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small circles of arbitrary radii.
[Figure 2]
Figure 2
The mol­ecule of (II)[link]. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small circles of arbitrary radii.
[Figure 3]
Figure 3
A layer of mol­ecules of (I)[link]. Displacement ellipsoids are drawn at the 20% probability level and H atoms involved in C—H⋯O contacts (shorter dashed lines) are shown as small circles of arbitrary radii. The longer dashed lines represent short contacts mentioned in the Comment. Selected atoms are labelled. [Symmetry codes: (i) −x + 1, −y + 1, −z + 1; (iii) −x + 1, y − [{1\over 2}], −z + [{1\over 2}]; (iv) −x + 1, y + [{1\over 2}], −z + [{1\over 2}]; (v) x, −y + [{3\over 2}], z + [{1\over 2}]; (vi) x, −y + [{1\over 2}], z + [{1\over 2}].]
[Figure 4]
Figure 4
A layer of mol­ecules of (II)[link]. Displacement ellipsoids are drawn at the 20% probability level and H atoms involved in C—H⋯O and C—H⋯Cl contacts (dashed lines) are shown as small circles of arbitrary radii. Selected atoms are labelled. [Symmetry codes: (ii) −x, −y + 1, −z; (iii) −x + 1, y − [{1\over 2}], −z + [{1\over 2}]; (iv) −x + 1, y + [{1\over 2}], −z + [{1\over 2}]; (vii) x + 1, −y + [{1\over 2}], z + [{1\over 2}]; (viii) x + 1, −y + [{3\over 2}], z + [{1\over 2}]; (ix) −x + 2, −y + 1, −z + 1.]

Experimental

Irradiation through Pyrex for 15 h of a solution of N-eth­yl-3,4,5,6-tetra­chloro­phthalimide (2.0 g, 6.4 mmol) and cyclo­hexene (27.2 g, 0.33 mol) in acetonitrile (300 ml) resulted in the formation of two products. After removal of solvents under vacuum, flash chromatography on silica gel, with dieth­yl ether–light petroleum (b.p. 313–333 K) (3:97 increased stepwise to 7:93) as eluant, yielded in order of recovery from the column: (i) unreacted N-ethyl­tetra­chloro­phthalimide (576 mg. 1.8 mmol), identified by comparison of its IR spectrum with that of a known sample; (ii) compound (I)[link]; (iii) compound (II)[link]. Compound (I)[link] is a white crystalline solid [yield 510 mg, 28%; m.p. 443–445 K (from light petroleum, b.p. 333–353 K)]. Analysis found: C 48.1, H 3.7, N 3.2, Cl 36.2%; C16H15Cl4NO2 requires C 48.6, H 3.8, N 3.5, Cl 35.9%. λmax (MeCN) 208 (∊ = 13 758 dm3 mol−1 cm−1) and 242 nm (15 539); νmax 1768 and 1709 cm−1 (C=O); 1H NMR (270 MHz, CDCl3): δ 3.7 (2H, q, N–CH2), 2.25 (lH, m), 0.8–2.1 (9H, complex multiplets), 1.2 (3H, t, Me); 13C NMR (67.8 MHz, CDCl3): δ 168.3, 162.2, 147.0, 133.0, 129.1, 125.6, 78.3, 58.4, 57.3, 51.7, 34.3, 29.3, 28.7, 27.0, 26.6, 13.4; m/e: 393 (M+, 1%), 362 (18), 360 (54), 358 (55), 329 (37), 327 (77), 325 (59), 318 (10), 316 (33), 314 (65), 312 (52), 294 (12), 292 (340), 290 (36), 82 (70), 67 (l00), 69 (24), 54 (44), 41 (26). Compound (II)[link] is a white crystalline solid [yield 277 mg, 15%; m.p. 431–432 K (from light petroleum, b.p. 333–353 K)]. Analysis found: C 49.3, H 3.9, N 3.3, Cl 33.4%; C16H15Cl4NO2 requires: C 48.6, H 3.8, N 3.5, Cl 35.9%. λmax 207 (∊ = 9344 dm3 mol−1 cm−1) and 242 nm (11 844); νmax 1769 and 1708 cm−l (C=O), 1664 and 1587 cm−1 (C=C); 1H NMR (270 MHz; CDCl3): δ 3.7 (2H, q, J = 6 Hz, N–CH2–), 2.2 (2H, m), 1.9 (2H, m), 1.6 (2H, m), 1.0–1.5 (4H, m), 1.2 (3H, t, J = 7 Hz, Me); 13C NMR (67.8 MHz; CDCl3): δ 168.1, 161.5, 139.0, 138.5, 135.1, 123.5, 78.5, 58.9, 58.8, 57.9, 53.4, 34.4, 29.2, 27.0, 26.9, 13.3; m/e: 393 (M+, 3%), 362 (13), 360 (43), 358 (44), 329 (18), 327 (33), 325 (26), 318 (10), 316 (33), 314 (62), 312 (49), 294 (16), 292 (40), 290 (43), 82 (73), 69 (14), 67 (100), 54 (38), 41 (43).

Compound (I)[link]

Crystal data

  • C16H15Cl4NO2

  • Mr = 395.09

  • Monoclinic, P 21 /c

  • a = 10.705 (17) Å

  • b = 9.269 (12) Å

  • c = 17.53 (3) Å

  • β = 97.83 (13)°

  • V = 1723 (5) Å3

  • Z = 4

  • Dx = 1.523 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 14 reflections

  • θ = 10.0–12.3°

  • μ = 0.69 mm−1

  • T = 298 (2) K

  • Prism, colourless

  • 0.60 × 0.32 × 0.25 mm
Data collection

  • Nicolet P3 four-circle diffractometer

  • θ–2θ scans

  • Absorption correction: ψ scan(North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.])Tmin = 0.606, Tmax = 0.841

  • 5280 measured reflections

  • 5047 independent reflections

  • 2697 reflections with I > 2σ(I)

  • Rint = 0.036

  • θmax = 30.1°

  • h = 0 → 15

  • k = 0 → 13

  • l = −24 → 24

  • 2 standard reflections every 50 reflections intensity decay: 0%
Refinement

  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.063

  • wR(F2) = 0.159

  • S = 1.00

  • 5047 reflections

  • 209 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0676P)2] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.59 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °) for (I)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C6—H6B⋯O2i 0.97 2.53 3.434 (7) 154
Symmetry code: (i) -x+1, -y+1, -z+1.

Compound (II)[link]

Crystal data

  • C16H15Cl4NO2

  • Mr = 395.09

  • Monoclinic, P 21 /c

  • a = 10.937 (7) Å

  • b = 9.228 (4) Å

  • c = 17.100 (6) Å

  • β = 94.83 (4)°

  • V = 1719.7 (15) Å3

  • Z = 4

  • Dx = 1.526 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 14 reflections

  • θ = 11.1–13.2°

  • μ = 0.70 mm−1

  • T = 298 (2) K

  • Block, colourless

  • 0.60 × 0.60 × 0.38 mm
Data collection

  • Nicolet P3 four-circle diffractometer

  • θ–2θ scans

  • Absorption correction: ψ scan(North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.])Tmin = 0.567, Tmax = 0.768

  • 5269 measured reflections

  • 5043 independent reflections

  • 3191 reflections with I > 2σ(I)

  • Rint = 0.023

  • θmax = 30.1°

  • h = 0 → 15

  • k = 0 → 13

  • l = −24 → 24

  • 2 standard reflections every 50 reflections intensity decay: 0%
Refinement

  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.053

  • wR(F2) = 0.134

  • S = 1.04

  • 5043 reflections

  • 209 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0612P)2 + 0.2253P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.63 e Å−3

  • Δρmin = −0.33 e Å−3

Table 2
Hydrogen-bond geometry (Å, °) for (II)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C7—H7⋯O2ii 0.98 2.49 3.428 (3) 161
C6—H6A⋯Cl4iii 0.97 2.81 3.669 (3) 147
Symmetry codes: (ii) -x, -y+1, -z; (iii) [-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Table 3
Selected torsion angles (°) for (I)–(III)

   (I)  (II)  (III)a
C10—C1—C2—C3 −160.5 (3) −85.4 (2) −159.1 (4)
C11—C1—C2—C3 85.8 (4) 160.6 (2) 86.5 (4)
C13—C1—C2—C3 −48.9 (4) 31.3 (3) −48.3 (5)
C10—C1—C2—C7 68.6 (3) 39.8 (2) 69.5 (3)
C11—C1—C2—C7 −45.1 (3) −74.1 (2) −44.9 (4)
C13—C1—C2—C7 −179.7 (3) 156.59 (19) −179.7 (3)
C1—C2—C7—C6 −154.6 (3) 154.62 (19) −155.5 (3)
C3—C2—C7—C6 67.8 (4) −72.1 (2) 65.8 (4)
C1—C2—C7—C8 −16.6 (3) 22.7 (2) −18.0 (4)
C3—C2—C7—C8 −154.1 (3) 155.98 (19) −156.7 (3)
C2—C7—C8—C12 68.7 (3) 39.5 (2) 69.7 (4)
C6—C7—C8—C12 −159.6 (3) −85.4 (3) −158.8 (4)
C2—C7—C8—C9 −43.9 (3) −73.4 (2) −44.1 (4)
C6—C7—C8—C9 87.7 (4) 161.7 (2) 87.4 (4)
Note: (a) the values given are for the enantiomer of the molecule selected as the asymmetric unit of the racemic structure described by McSweeney et al. (2005[McSweeney, N., Pratt, A. C., Long, C. & Howie, R. A. (2005). Acta Cryst. E61, o547-o549.]).

In the final stages of refinement, H atoms were introduced in calculated positions, with C—H distances of 0.96, 0.97 and 0.98 Å for meth­yl, methyl­ene and tertiary H atoms, respectively, and refined using a riding model with Uiso(H) values of 1.5Ueq(C) for meth­yl H atoms and 1.2Ueq(C) otherwise. The rotational orientation of the meth­yl groups was also refined.

For both compounds, data collection: Nicolet P3 Software (Nicolet, 1980[Nicolet (1980). Nicolet P3 Software. Nicolet XRD Corporation, Cupertino, California, USA.]); cell refinement: Nicolet P3 Software; data reduction: RDNIC (Howie, 1980[Howie, R. A. (1980). RDNIC. University of Aberdeen, Scotland.]); structure solution: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); structure refinement: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); publication software: SHELXL97 and PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]).

Supporting information

Crystal structure: contains datablocks global, I, II. DOI: 10.1107/S0108270105010218/gd1384sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270105010218/gd1384Isup2.hkl

Structure factors: contains datablock II. DOI: 10.1107/S0108270105010218/gd1384IIsup3.hkl


Comment top

The photochemistry of phthalimides has been studied extensively and has been reviewed by Kanaoka (1978), Coyle (1984) and Oelgemöller & Griesbeck (2002). Schwack (1987), Suau et al. (1989) and Kubo et al. (1989) have all reported the photoinduced para-cycloaddition of alkenes to various N-substituted phthalimides to yield products analogous to the title compounds. However, the spectroscopic methods used for product structural elucidation left the precise product stereochemistries unresolved. The stereochemistries of two related diastereomeric 1,4-cycloadducts, (I) and (II), formed by photoreaction of N-ethyl-4,5,6,7-tetrachlorophthalimide with cyclohexene, are reported here.

Fig. 1 shows the (1R,2R,7R,8R)-enantiomer of the major photoadduct, (I), isolated from irradiation of N-ethyltetrachlorophthalimide in the presence of cyclohexene. The (1R,2S,7S,8R)-enantiomer of the minor photoadduct (II) is shown in Fig. 2. Corresponding bond lengths and angles for (I) and (II) are generally similar and most have values which are typical of their types. Exceptions include the C9—C10—C14 angles of 135.5 (3) and 135.0 (2)° for (I) and (II), respectively. Also notable are the Cl1—C8 bonds, of 1.768 (3) and 1.770 (2) Å in (I) and (II), respectively, which are significantly longer than the remaining C—Cl bonds, which range from 1.704 (2) to 1.714 (4) Å. While the distances to atoms Cl3 and Cl4 are typical of those in Cl—C═C—Cl fragments, those to Cl2 are short for their type (mean value 1.734 Å; Allen et al., 1987). Those to Cl1, on the other hand, are typical of Cl—C(C)2—C(C)2—Cl bonds, but are much shorter than isolated Cl—C(C)3 bonds.

From Figs. 1 and 2 it is clear that the difference between the isomers is the disposition of the H atoms at the stereogenic centres at C2 and C7. The torsion angles given in Table 1 confirm this. Also present in Table 1 are the corresponding values for N-benzoyltricyclododecadienedicarboximide, (III), in the same enantiomeric form as (I) and (II), whose structure has been described by McSweeney et al. (2005). Adduct (III), which is formed as a single diastereoisomer by the photoaddition of cyclohexene to N-benzoylphthalimide, is wholly analogous to (I) and (II), apart from the N-substituent and the absence of Cl atoms. The crystals of (I), (II) and (III) are all alike in being racemic with enantiomers that differ in the configurations at C1 and C8 in the product molecules. This is because there are two equally probable choices for the 1,4 atom pair of the parent phthalimide at which addition to the cyclohexene can take place. The data in Table 1 correspond, therefore, for (I) and (II) to the molecule selected as the asymmetric unit, but for (III) to the enantiomer of the molecule selected as the asymmetric unit of the structure as described by McSweeney et al. (2005). The torsion angles about the C1—C2 and C7—C8 bonds clearly show the structural difference between the diastereoisomers (I) and (II). These values also show that the isomeric form of (III) is the same as that of (I) and different from that of (II). The stereochemical relationship between (I) and (II) is also evident in the pucker parameters (Cremer & Pople, 1975) associated with the cyclohexane ring defined by atoms C2–C7. The parameters, with those for (II) in square brackets, are Q = 0.575 (4) Å [0.628 (3) Å], θ = 13.1 (4)° [166.6 (3)°] and ϕ = 337.3 (16)° [151.6 (11)°]. In terms of θ and ϕ, these are related as required for inversion of the conformation of the ring consistent with the different configurations at C2 and C7 for the two diastereoisomers.

The packing of the molecules of (I) creates layers parallel to (100) and, for the choice of origin used in the refinement, centred on x = 0 (Fig. 3) within which the C6—H6.·O2 hydrogen-bonds (Table 2) create centrosymmetric dimers, such as that shown in the centre of the cell. Further short contacts [Cl3···O2ii; symmetry code: (ii) 1 − x, y − 1/2, 1/2 − z] are found between the dimers and within the layer of molecules. In (II), the molecules are found in layers parallel to (−1,0,2), interconnected as shown in Fig. 4 by the hydrogen-bonds given in Table 3.

The racemic nature of (III) and of the isomers (I) and (II), a prerequisite for the refinement of the structures in centrosymmetric space groups, is a natural consequence of the manner in which the compounds have been formed by para-cycloaddition of achiral reactants. There are four possible racemic products, viz. two involving trans ring junctions across the C2—C7 bond and two involving cis junctions across the C2—C7 bond arising from 1,4-addition across the aromatic ring, which must of necessity be cis. Formation of a single unsymmetrical diastereoisomer from N-benzoylphthalimide suggests a favoured approach by the cyclohexene to the excited phthalimide, possibly involving minimization, in the transition state, of steric interactions between the N-benzoyl imide ring and the cyclohexene. For N-ethyltetrachlorophthalimide, on the other hand, two diastereoisomers are formed, presumably reflecting lesser differentiation between the reaction pathways arising from the presence of the chlorines and the sterically less-demanding ethyl group. The stereochemistry at the C2–C7 ring junction in both cases is the outcome of overall trans addition across the cyclohexene double bond.

Experimental top

Irradiation through Pyrex for 15 h of a solution of N-ethyl-4,5,6,7-tetrachlorophthalimide (2.0 g, 6.4 mmol) and cyclohexene (27.2 g, 0.33 mol) in acetonitrile (300 ml) resulted in the formation of two products. After removal of solvents under vacuum, flash chromatography on silica gel, with diethyl ether–light petroleum (b.p. 313–333 K; 3:97 increased stepwise to 7:93) as eluant, yielded, in order of recovery from the column (i) unreacted N-ethyltetrachlorophthalimide (576 mg. 1.8 mmol) identified by comparison of its IR spectrum with that of a known sample, (ii) compound (I) and (iii) compound (II). Compound (I) is a white crystalline solid [510 mg, 28%; m.p. 443–445 K (from light petroleum b.p. 333–353 K)]. Found: C 48.1, H 3.7, N 3.2, Cl 36.2%; C16H15Cl4NO2 requires C 48.6, H 3.8, N 3.5, Cl 35.9%; λmax (MeCN) 208 (ε = 13 758 dm3 mol−1 cm−1) and 242 nm (15 539); νmax 1768 and 1709 cm−1 (C═O); 1H NMR (270 MHz, CDCl3): δ 3.7 (2H, q, N—CH2), 2.25 (lH, m), 0.8–2.1 (9H, complex multiplets), 1.2 (3H, t, Me); 13C NMR (67.8 MHz, CDCl3): δ 168.3, 162.2, 147.0, 133.0, 129.1, 125.6, 78.3, 58.4, 57.3, 51.7, 34.3, 29.3, 28.7, 27.0, 26.6, 13.4; m/e 393 (M+, 1%), 362 (18), 360 (54), 358 (55), 329 (37), 327 (77), 325 (59), 318 (10), 316 (33), 314 (65), 312 (52), 294 (12), 292 (340), 290 (36), 82 (70), 67 (l00), 69 (24), 54 (44), 41 (26). Compound (II) is a white crystalline solid [277 mg, 15%; m.p. 431–432 K (from light petroleum b.p. 333–353 K)]. Found: C 49.3, H 3.9, N 3.3, Cl 33.4; C16H15Cl4NO2 requires: C 48.6, H 3.8, N 3.5, Cl 35.9%; λmax 207 (ε = 9344 dm3 mol−1 cm−1) and 242 nm (11844); νmax 1769 and 1708 cm-l (C═O), 1664 and 1587 cm−1 (C═C); 1H NMR (270 MHz; CDCl3): δ 3.7 (2H, q, J = 6 Hz, N—CH2–), 2.2 (2H, m), 1.9 (2H, m), 1.6 (2H, m), 1.0–1.5 (4H, m), 1.2 (3H, t, J = 7 Hz, Me); 13C NMR (67.8 MHz; CDCl3): δ 168.1, 161.5, 139.0, 138.5, 135.1, 123.5, 78.5, 58.9, 58.8, 57.9, 53.4, 34.4, 29.2, 27.0, 26.9, 13.3; m/e 393 (M+, 3%), 362 (13), 360 (43), 358 (44), 329 (18), 327 (33), 325 (26), 318 (10), 316 (33), 314 (62), 312 (49), 294 (16), 292 (40), 290 (43), 82 (73), 69 (14), 67 (100), 54 (38), 41 (43).

Refinement top

In the final stages of refinement, H atoms were introduced in calculated positions with C—H distances of 0.96, 0.97 and 0.98 Å for methyl, methylene and tertiary H atoms, respectively, and refined with a riding model with Uiso(H) = 1.5Ueq(C) for methyl H atoms and Uiso(H) = 1.2Ueq(C) otherwise. The rotational orientation of the methyl groups was also refined.

Computing details top

For both compounds, data collection: Nicolet P3 Software (Nicolet, 1980); cell refinement: Nicolet P3 Software; data reduction: RDNIC (Howie, 1980); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecule of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small circles of arbitrary radii.
[Figure 2] Fig. 2. The molecule of (II). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small circles of arbitrary radii.
[Figure 3] Fig. 3. A layer of molecules of (I). Displacement ellipsoids are drawn at the 20% probability level and H atoms involved in C—H···O contacts (shorter dashed lines) are shown as small circles of arbitrary radii. The longer dashed lines represent short contacts mentioned in the text. Selected atoms are labelled. [Symmetry codes: (i) 1 − x, 1 − y, 1 − z; (ii) 1 − x, y − 1/2, 1/2 − z; (iii) 1 − x, 1/2 + y, 1/2 − z; (iv) x, 3/2 − y, 1/2 + z; (v) x, 1/2 − y, 1/2 + z.]
[Figure 4] Fig. 4. A layer of molecules of (II). Displacement ellipsoids are drawn at the 20% probability level and H atoms involved in C—H···O and C—H···Cl contacts (dashed lines) are shown as small circles of arbitrary radii. Selected atoms are labelled. [Symmetry codes: (i) −x, 1 − y, −z; (ii) 1 − x, y − 1/2, 1/2 − z; (iii) 1 − x, 1/2 + y, 1/2 − z; (iv) 1 + x, 1/2 − y, 1/2 + z; (v) 1 + x, 3/2 − y, 1/2 + z; (vi) 2 − x, 1 − y, 1 − z.]
(I) (1RS,2RS,7RS,8RS)-8,9,11,12-Tetrachloro-N-ethyltricyclo[6.2.2.02,7]dodeca- 9,11-diene-1,10-dicarboximide top
Crystal data top
C16H15Cl4NO2F(000) = 808
Mr = 395.09Dx = 1.523 Mg m−3
Monoclinic, P21/cMelting point = 443–445 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 10.705 (17) ÅCell parameters from 14 reflections
b = 9.269 (12) Åθ = 10.0–12.3°
c = 17.53 (3) ŵ = 0.69 mm−1
β = 97.83 (13)°T = 298 K
V = 1723 (5) Å3Prism, colourless
Z = 40.60 × 0.32 × 0.25 mm
Data collection top
Nicolet P3 four-circle
diffractometer		2697 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tubeRint = 0.036
Graphite monochromatorθmax = 30.1°, θmin = 1.9°
θ–2θ scansh = 0→15
Absorption correction: ψ scan
(North et al., 1968)		k = 0→13
Tmin = 0.606, Tmax = 0.841l = −24→24
5280 measured reflections2 standard reflections every 50 reflections
5047 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.063Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.159H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0676P)2]
where P = (Fo2 + 2Fc2)/3
5047 reflections(Δ/σ)max < 0.001
209 parametersΔρmax = 0.59 e Å−3
0 restraintsΔρmin = −0.27 e Å−3
Crystal data top
C16H15Cl4NO2V = 1723 (5) Å3
Mr = 395.09Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.705 (17) ŵ = 0.69 mm−1
b = 9.269 (12) ÅT = 298 K
c = 17.53 (3) Å0.60 × 0.32 × 0.25 mm
β = 97.83 (13)°
Data collection top
Nicolet P3 four-circle
diffractometer		2697 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)		Rint = 0.036
Tmin = 0.606, Tmax = 0.8412 standard reflections every 50 reflections
5280 measured reflections intensity decay: none
5047 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0630 restraints
wR(F2) = 0.159H-atom parameters constrained
S = 1.01Δρmax = 0.59 e Å−3
5047 reflectionsΔρmin = −0.27 e Å−3
209 parameters
Special details top

Experimental. Scan rates, dependent on prescan intensity (Ip), were in the range 58.6 (Ip>2500) to 5.33 (Ip<150) ° 2θ min−1. Scan widths, dependent on 2θ, were in the range 2.4 to 2.7 ° 2θ. Stationary crystal, stationary counter background counts were taken on either side of the peak each for 25% of the total (peak plus background) count time.

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)

− 1.8700 (0.0151) x − 3.9786 (0.0152) y + 15.8082 (0.0375) z = 3.3148 (0.0132)

* 0.0241 (0.0017) C1 * −0.0290 (0.0017) C10 * −0.0108 (0.0018) C13 * 0.0233 (0.0017) C14 * −0.0076 (0.0019) N1 − 0.0043 (0.0048) O1 0.0896 (0.0044) O2 1.3881 (0.0052) C2 − 0.0166 (0.0047) C9 − 1.1158 (0.0051) C11 − 0.1000 (0.0057) C15 − 1.5192 (0.0071) C16

Rms deviation of fitted atoms = 0.0207

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 (Å2) top
xyzUiso*/Ueq
Cl10.05670 (9)0.61101 (11)0.36427 (6)0.0670 (3)
Cl20.33128 (11)0.71615 (9)0.42965 (5)0.0664 (3)
Cl30.30089 (10)0.27524 (11)0.17652 (5)0.0616 (3)
Cl40.07020 (9)0.49295 (12)0.19801 (5)0.0635 (3)
O10.5048 (2)0.1318 (3)0.30229 (16)0.0637 (7)
O20.6102 (2)0.5563 (3)0.42754 (14)0.0606 (7)
N10.5846 (2)0.3381 (3)0.36345 (15)0.0464 (7)
C10.3649 (3)0.3232 (3)0.33572 (15)0.0327 (6)
C20.2845 (3)0.2537 (3)0.39500 (17)0.0336 (6)
H20.33260.27430.44550.040*
C30.2562 (4)0.0943 (4)0.3974 (2)0.0553 (9)
H3A0.33310.03870.39800.066*
H3B0.19800.06640.35250.066*
C40.1981 (4)0.0674 (4)0.4703 (2)0.0552 (9)
H4A0.26360.07670.51400.066*
H4B0.1677−0.03130.46940.066*
C50.0891 (3)0.1682 (4)0.48243 (19)0.0490 (8)
H5A0.01480.13870.44800.059*
H5B0.07080.15620.53470.059*
C60.1127 (3)0.3267 (4)0.4691 (2)0.0499 (8)
H6A0.03470.38070.46740.060*
H6B0.17290.36470.51060.060*
C70.1638 (3)0.3409 (3)0.39391 (17)0.0407 (7)
H70.10230.28980.35700.049*
C80.1818 (3)0.4910 (3)0.35405 (17)0.0396 (7)
C90.3126 (3)0.5524 (3)0.38465 (17)0.0415 (7)
C100.4050 (3)0.4655 (3)0.37291 (15)0.0340 (6)
C110.2787 (3)0.3558 (3)0.26162 (16)0.0387 (7)
C120.1865 (3)0.4455 (3)0.27034 (16)0.0391 (7)
C130.4885 (3)0.2486 (4)0.32937 (18)0.0429 (7)
C140.5429 (3)0.4662 (4)0.39272 (17)0.0428 (7)
C150.7180 (3)0.3023 (5)0.3644 (2)0.0673 (11)
H15A0.72920.19890.37040.081*
H15B0.76720.34890.40810.081*
C160.7649 (4)0.3496 (5)0.2920 (3)0.0781 (13)
H16A0.71390.30700.24860.117*
H16B0.85080.31930.29290.117*
H16C0.76010.45280.28810.117*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0688 (6)0.0607 (6)0.0760 (6)0.0347 (5)0.0254 (5)0.0082 (5)
Cl20.1122 (8)0.0303 (4)0.0564 (5)−0.0015 (5)0.0102 (5)−0.0104 (4)
Cl30.0815 (7)0.0686 (6)0.0359 (4)0.0046 (5)0.0120 (4)−0.0153 (4)
Cl40.0584 (5)0.0735 (7)0.0533 (5)0.0103 (5)−0.0114 (4)0.0119 (4)
O10.0539 (15)0.0507 (15)0.0903 (19)0.0148 (12)0.0231 (14)−0.0116 (14)
O20.0595 (15)0.0689 (17)0.0507 (13)−0.0318 (14)−0.0020 (11)0.0028 (12)
N10.0322 (14)0.0622 (18)0.0450 (14)0.0010 (13)0.0063 (11)0.0067 (13)
C10.0337 (15)0.0293 (14)0.0359 (14)0.0012 (12)0.0079 (12)−0.0053 (11)
C20.0326 (15)0.0308 (14)0.0387 (14)−0.0003 (12)0.0095 (12)0.0003 (12)
C30.061 (2)0.0387 (18)0.069 (2)−0.0030 (17)0.0184 (19)−0.0047 (17)
C40.069 (2)0.0379 (18)0.062 (2)−0.0086 (17)0.0210 (19)0.0073 (16)
C50.050 (2)0.052 (2)0.0479 (18)−0.0146 (17)0.0172 (15)−0.0063 (16)
C60.052 (2)0.0474 (19)0.0534 (19)0.0004 (16)0.0175 (16)−0.0055 (16)
C70.0409 (17)0.0382 (16)0.0444 (17)0.0028 (14)0.0112 (13)−0.0019 (13)
C80.0427 (17)0.0371 (16)0.0407 (15)0.0144 (14)0.0114 (13)0.0006 (13)
C90.064 (2)0.0277 (14)0.0343 (15)−0.0041 (15)0.0117 (14)−0.0005 (12)
C100.0388 (16)0.0310 (14)0.0328 (14)−0.0070 (12)0.0066 (12)−0.0005 (11)
C110.0472 (18)0.0392 (16)0.0299 (14)−0.0023 (14)0.0064 (13)−0.0063 (12)
C120.0392 (16)0.0434 (17)0.0339 (14)0.0018 (14)0.0015 (12)0.0044 (13)
C130.0378 (17)0.0466 (19)0.0463 (17)0.0034 (15)0.0127 (14)0.0027 (15)
C140.0447 (18)0.0514 (19)0.0326 (15)−0.0104 (16)0.0061 (13)0.0091 (14)
C150.0314 (18)0.099 (3)0.072 (2)0.003 (2)0.0067 (17)0.011 (2)
C160.058 (2)0.093 (3)0.092 (3)0.005 (2)0.040 (2)0.008 (3)
Geometric parameters (Å, º) top
Cl1—C81.768 (3)C4—H4B0.9700
Cl2—C91.710 (4)C5—C61.515 (5)
Cl3—C111.714 (4)C5—H5A0.9700
Cl4—C121.709 (4)C5—H5B0.9700
O1—C131.205 (4)C6—C71.499 (5)
O2—C141.212 (4)C6—H6A0.9700
N1—C131.391 (4)C6—H6B0.9700
N1—C141.391 (5)C7—C81.581 (4)
N1—C151.464 (5)C7—H70.9800
C1—C101.507 (4)C8—C121.534 (5)
C1—C131.510 (4)C8—C91.540 (5)
C1—C111.518 (5)C9—C101.313 (4)
C1—C21.575 (4)C10—C141.470 (5)
C2—C31.510 (5)C11—C121.315 (4)
C2—C71.521 (4)C15—C161.492 (6)
C2—H20.9800C15—H15A0.9700
C3—C41.516 (5)C15—H15B0.9700
C3—H3A0.9700C16—H16A0.9600
C3—H3B0.9700C16—H16B0.9600
C4—C51.532 (5)C16—H16C0.9600
C4—H4A0.9700
C13—N1—C14114.3 (3)C2—C7—C8108.6 (3)
C13—N1—C15122.2 (3)C6—C7—H7104.2
C14—N1—C15123.4 (3)C2—C7—H7104.2
C10—C1—C13103.4 (3)C8—C7—H7104.2
C10—C1—C11107.4 (2)C12—C8—C9106.7 (3)
C13—C1—C11117.7 (3)C12—C8—C7101.7 (2)
C10—C1—C2102.8 (2)C9—C8—C7109.3 (3)
C13—C1—C2115.2 (3)C12—C8—Cl1113.2 (2)
C11—C1—C2108.8 (3)C9—C8—Cl1113.4 (2)
C3—C2—C7110.3 (3)C7—C8—Cl1111.7 (2)
C3—C2—C1123.2 (3)C10—C9—C8112.8 (3)
C7—C2—C1108.3 (2)C10—C9—Cl2125.0 (3)
C3—C2—H2104.4C8—C9—Cl2122.2 (2)
C7—C2—H2104.4C9—C10—C14135.5 (3)
C1—C2—H2104.4C9—C10—C1115.4 (3)
C2—C3—C4106.9 (3)C14—C10—C1108.9 (3)
C2—C3—H3A110.3C12—C11—C1113.9 (3)
C4—C3—H3A110.3C12—C11—Cl3124.9 (3)
C2—C3—H3B110.3C1—C11—Cl3121.2 (2)
C4—C3—H3B110.3C11—C12—C8114.1 (3)
H3A—C3—H3B108.6C11—C12—Cl4124.0 (3)
C3—C4—C5115.1 (3)C8—C12—Cl4121.6 (2)
C3—C4—H4A108.5O1—C13—N1124.6 (3)
C5—C4—H4A108.5O1—C13—C1128.0 (3)
C3—C4—H4B108.5N1—C13—C1107.4 (3)
C5—C4—H4B108.5O2—C14—N1125.1 (3)
H4A—C4—H4B107.5O2—C14—C10129.2 (3)
C6—C5—C4115.1 (3)N1—C14—C10105.7 (3)
C6—C5—H5A108.5N1—C15—C16111.4 (3)
C4—C5—H5A108.5N1—C15—H15A109.3
C6—C5—H5B108.5C16—C15—H15A109.3
C4—C5—H5B108.5N1—C15—H15B109.3
H5A—C5—H5B107.5C16—C15—H15B109.3
C7—C6—C5108.0 (3)H15A—C15—H15B108.0
C7—C6—H6A110.1C15—C16—H16A109.5
C5—C6—H6A110.1C15—C16—H16B109.5
C7—C6—H6B110.1H16A—C16—H16B109.5
C5—C6—H6B110.1C15—C16—H16C109.5
H6A—C6—H6B108.4H16A—C16—H16C109.5
C6—C7—C2110.7 (3)H16B—C16—H16C109.5
C6—C7—C8123.1 (3)
C10—C1—C2—C3−160.5 (3)C2—C1—C10—C14115.4 (3)
C13—C1—C2—C3−48.9 (4)C10—C1—C11—C12−50.8 (3)
C11—C1—C2—C385.8 (4)C13—C1—C11—C12−166.9 (3)
C10—C1—C2—C768.6 (3)C2—C1—C11—C1259.8 (3)
C13—C1—C2—C7−179.7 (3)C10—C1—C11—Cl3131.2 (2)
C11—C1—C2—C7−45.1 (3)C13—C1—C11—Cl315.1 (4)
C7—C2—C3—C4−60.0 (4)C2—C1—C11—Cl3−118.2 (3)
C1—C2—C3—C4169.9 (3)C1—C11—C12—C8−3.2 (4)
C2—C3—C4—C549.9 (4)Cl3—C11—C12—C8174.7 (2)
C3—C4—C5—C6−46.3 (4)C1—C11—C12—Cl4−176.0 (2)
C4—C5—C6—C748.0 (4)Cl3—C11—C12—Cl41.8 (4)
C5—C6—C7—C2−58.3 (4)C9—C8—C12—C1154.7 (4)
C5—C6—C7—C8170.9 (3)C7—C8—C12—C11−59.8 (3)
C3—C2—C7—C667.8 (4)Cl1—C8—C12—C11−179.8 (2)
C1—C2—C7—C6−154.6 (3)C9—C8—C12—Cl4−132.3 (3)
C3—C2—C7—C8−154.1 (3)C7—C8—C12—Cl4113.2 (3)
C1—C2—C7—C8−16.6 (3)Cl1—C8—C12—Cl4−6.8 (3)
C6—C7—C8—C12−159.6 (3)C14—N1—C13—O1−178.2 (3)
C2—C7—C8—C1268.7 (3)C15—N1—C13—O14.8 (5)
C6—C7—C8—C987.7 (4)C14—N1—C13—C1−0.1 (3)
C2—C7—C8—C9−43.9 (3)C15—N1—C13—C1−177.1 (3)
C6—C7—C8—Cl1−38.6 (4)C10—C1—C13—O1−179.0 (3)
C2—C7—C8—Cl1−170.3 (2)C11—C1—C13—O1−60.8 (5)
C12—C8—C9—C10−51.2 (3)C2—C1—C13—O169.7 (4)
C7—C8—C9—C1058.1 (3)C10—C1—C13—N13.0 (3)
Cl1—C8—C9—C10−176.5 (2)C11—C1—C13—N1121.2 (3)
C12—C8—C9—Cl2129.5 (2)C2—C1—C13—N1−108.4 (3)
C7—C8—C9—Cl2−121.3 (3)C13—N1—C14—O2176.6 (3)
Cl1—C8—C9—Cl24.1 (3)C15—N1—C14—O2−6.4 (5)
C8—C9—C10—C14−176.5 (3)C13—N1—C14—C10−2.9 (3)
Cl2—C9—C10—C142.8 (5)C15—N1—C14—C10174.0 (3)
C8—C9—C10—C1−2.5 (4)C9—C10—C14—O2−0.5 (6)
Cl2—C9—C10—C1176.9 (2)C1—C10—C14—O2−174.8 (3)
C13—C1—C10—C9179.7 (3)C9—C10—C14—N1179.0 (3)
C11—C1—C10—C954.5 (3)C1—C10—C14—N14.7 (3)
C2—C1—C10—C9−60.1 (3)C13—N1—C15—C1684.9 (5)
C13—C1—C10—C14−4.7 (3)C14—N1—C15—C16−91.8 (4)
C11—C1—C10—C14−129.9 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6B···O2i0.972.533.434 (7)154
Symmetry code: (i) −x+1, −y+1, −z+1.
(II) (1RS,2SR,7SR,8RS)-8,9,11,12-tetrachloro-N-ethyltricyclo[6.2.2.02,7]dodeca- 9,11-diene-1,10-dicarboximide top
Crystal data top
C16H15Cl4NO2F(000) = 808
Mr = 395.09Dx = 1.526 Mg m−3
Monoclinic, P21/cMelting point = 431–432 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 10.937 (7) ÅCell parameters from 14 reflections
b = 9.228 (4) Åθ = 11.1–13.2°
c = 17.100 (6) ŵ = 0.70 mm−1
β = 94.83 (4)°T = 298 K
V = 1719.7 (15) Å3Block, colourless
Z = 40.60 × 0.60 × 0.38 mm
Data collection top
Nicolet P3 four-circle
diffractometer		3191 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tubeRint = 0.023
Graphite monochromatorθmax = 30.1°, θmin = 1.9°
θ–2θ scansh = 0→15
Absorption correction: ψ scan
(North et al., 1968)		k = 0→13
Tmin = 0.567, Tmax = 0.768l = −24→24
5269 measured reflections2 standard reflections every 50 reflections
5043 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.053Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.134H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0612P)2 + 0.2253P]
where P = (Fo2 + 2Fc2)/3
5043 reflections(Δ/σ)max < 0.001
209 parametersΔρmax = 0.63 e Å−3
0 restraintsΔρmin = −0.33 e Å−3
Crystal data top
C16H15Cl4NO2V = 1719.7 (15) Å3
Mr = 395.09Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.937 (7) ŵ = 0.70 mm−1
b = 9.228 (4) ÅT = 298 K
c = 17.100 (6) Å0.60 × 0.60 × 0.38 mm
β = 94.83 (4)°
Data collection top
Nicolet P3 four-circle
diffractometer		3191 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)		Rint = 0.023
Tmin = 0.567, Tmax = 0.7682 standard reflections every 50 reflections
5269 measured reflections intensity decay: none
5043 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0530 restraints
wR(F2) = 0.134H-atom parameters constrained
S = 1.04Δρmax = 0.63 e Å−3
5043 reflectionsΔρmin = −0.33 e Å−3
209 parameters
Special details top

Experimental. Scan rates, dependent on prescan intensity (Ip), were in the range 58.6 (Ip>2500) to 5.33 (Ip<150) ° 2θ min−1. Scan widths, dependent on 2θ, were in the range 2.4 to 2.7 ° 2θ. Stationary crystal, stationary counter background counts were taken on either side of the peak each for 25% of the total (peak plus background) count time.

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)

− 1.5546 (0.0121) x + 4.5964 (0.0097) y + 14.7799 (0.0142) z = 3.9071 (0.0037)

* −0.0116 (0.0014) C1 * 0.0165 (0.0014) C10 * 0.0023 (0.0014) C13 * −0.0156 (0.0014) C14 * 0.0083 (0.0015) N1 − 0.0142 (0.0038) O1 − 0.0645 (0.0034) O2 − 1.2382 (0.0036) C2 0.1087 (0.0037) C9 1.1622 (0.0036) C11 0.1090 (0.0044) C15 1.5454 (0.0050) C16

Rms deviation of fitted atoms = 0.0120

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 (Å2) top
xyzUiso*/Ueq
Cl10.42297 (7)0.63798 (8)0.11988 (5)0.0599 (2)
Cl20.15292 (8)0.73415 (7)0.06375 (4)0.0571 (2)
Cl30.18670 (8)0.32614 (10)0.33293 (4)0.0647 (2)
Cl40.42108 (7)0.52336 (9)0.29420 (4)0.0629 (2)
O1−0.00113 (18)0.1542 (2)0.21532 (12)0.0598 (5)
O2−0.11320 (17)0.5598 (2)0.07399 (11)0.0516 (5)
N1−0.08288 (18)0.3508 (2)0.14710 (12)0.0428 (5)
C10.1314 (2)0.3453 (2)0.16999 (13)0.0333 (5)
C20.2263 (2)0.2593 (2)0.12374 (13)0.0341 (5)
H20.27850.20580.16320.041*
C30.1862 (2)0.1505 (3)0.05976 (15)0.0417 (5)
H3A0.14580.19960.01450.050*
H3B0.12960.08050.07890.050*
C40.3037 (3)0.0744 (3)0.03751 (17)0.0490 (6)
H4A0.33540.01420.08110.059*
H4B0.28300.0113−0.00700.059*
C50.4042 (3)0.1797 (3)0.01677 (17)0.0499 (6)
H5A0.37990.2229−0.03390.060*
H5B0.47900.12540.01170.060*
C60.4314 (2)0.3018 (3)0.07695 (16)0.0452 (6)
H6A0.46800.26260.12610.054*
H6B0.48770.37170.05740.054*
C70.3098 (2)0.3728 (2)0.08879 (13)0.0338 (5)
H70.27170.39610.03640.041*
C80.3047 (2)0.5153 (3)0.13893 (14)0.0384 (5)
C90.1760 (2)0.5730 (2)0.11201 (13)0.0358 (5)
C100.0890 (2)0.4799 (2)0.12558 (12)0.0341 (5)
C110.2103 (2)0.3936 (3)0.24269 (13)0.0382 (5)
C120.3038 (2)0.4762 (3)0.22635 (14)0.0401 (5)
C130.0110 (2)0.2683 (3)0.18223 (14)0.0410 (5)
C14−0.0453 (2)0.4767 (3)0.11028 (13)0.0380 (5)
C15−0.2129 (2)0.3150 (4)0.15138 (17)0.0573 (7)
H15A−0.22180.21100.15690.069*
H15B−0.25920.34430.10310.069*
C16−0.2636 (3)0.3902 (5)0.2198 (2)0.0740 (10)
H16A−0.21350.36760.26710.111*
H16B−0.34600.35790.22470.111*
H16C−0.26350.49300.21140.111*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0542 (4)0.0491 (4)0.0790 (5)−0.0233 (3)0.0206 (3)−0.0095 (3)
Cl20.0807 (5)0.0323 (3)0.0583 (4)−0.0011 (3)0.0062 (3)0.0119 (3)
Cl30.0813 (5)0.0791 (5)0.0334 (3)−0.0038 (4)0.0025 (3)0.0159 (3)
Cl40.0499 (4)0.0736 (5)0.0616 (4)−0.0023 (4)−0.0163 (3)−0.0190 (4)
O10.0567 (12)0.0526 (11)0.0715 (13)−0.0127 (9)0.0138 (10)0.0214 (10)
O20.0507 (11)0.0566 (11)0.0453 (10)0.0151 (9)−0.0095 (8)−0.0026 (9)
N10.0306 (10)0.0530 (13)0.0455 (11)−0.0048 (9)0.0066 (8)0.0011 (9)
C10.0321 (11)0.0318 (10)0.0366 (11)−0.0032 (9)0.0055 (9)0.0055 (9)
C20.0352 (11)0.0307 (11)0.0363 (11)−0.0006 (9)0.0028 (9)0.0032 (9)
C30.0475 (13)0.0319 (11)0.0458 (13)−0.0060 (10)0.0034 (11)−0.0008 (10)
C40.0576 (16)0.0318 (12)0.0587 (15)0.0021 (11)0.0103 (13)−0.0085 (11)
C50.0483 (15)0.0438 (14)0.0595 (16)0.0072 (12)0.0153 (12)−0.0073 (12)
C60.0358 (12)0.0422 (13)0.0582 (15)0.0005 (11)0.0080 (11)−0.0005 (12)
C70.0314 (11)0.0323 (11)0.0379 (11)−0.0018 (9)0.0043 (9)0.0006 (9)
C80.0387 (12)0.0337 (11)0.0436 (12)−0.0108 (10)0.0091 (10)−0.0021 (10)
C90.0468 (13)0.0284 (10)0.0329 (10)−0.0006 (9)0.0064 (9)0.0012 (8)
C100.0405 (12)0.0318 (10)0.0301 (10)0.0018 (9)0.0037 (9)0.0005 (8)
C110.0446 (13)0.0416 (12)0.0280 (10)0.0039 (10)0.0016 (9)0.0040 (9)
C120.0381 (12)0.0431 (13)0.0383 (12)0.0001 (10)−0.0026 (9)−0.0074 (10)
C130.0392 (13)0.0425 (13)0.0428 (12)−0.0065 (11)0.0112 (10)0.0032 (10)
C140.0393 (12)0.0434 (12)0.0310 (10)0.0050 (10)0.0019 (9)−0.0055 (9)
C150.0333 (13)0.077 (2)0.0612 (17)−0.0111 (13)0.0032 (12)−0.0053 (15)
C160.0460 (17)0.101 (3)0.077 (2)−0.0054 (18)0.0207 (16)−0.012 (2)
Geometric parameters (Å, º) top
Cl1—C81.770 (2)C4—H4B0.9700
Cl2—C91.709 (2)C5—C61.538 (4)
Cl3—C111.704 (2)C5—H5A0.9700
Cl4—C121.712 (3)C5—H5B0.9700
O1—C131.208 (3)C6—C71.512 (3)
O2—C141.203 (3)C6—H6A0.9700
N1—C131.376 (3)C6—H6B0.9700
N1—C141.399 (3)C7—C81.573 (3)
N1—C151.468 (3)C7—H70.9800
C1—C101.508 (3)C8—C121.538 (3)
C1—C111.519 (3)C8—C91.539 (4)
C1—C131.526 (3)C9—C101.317 (3)
C1—C21.572 (3)C10—C141.470 (3)
C2—C31.522 (3)C11—C121.324 (3)
C2—C71.543 (3)C15—C161.506 (4)
C2—H20.9800C15—H15A0.9700
C3—C41.540 (4)C15—H15B0.9700
C3—H3A0.9700C16—H16A0.9600
C3—H3B0.9700C16—H16B0.9600
C4—C51.531 (4)C16—H16C0.9600
C4—H4A0.9700
C13—N1—C14114.78 (19)C2—C7—C8107.87 (17)
C13—N1—C15123.0 (2)C6—C7—H7106.5
C14—N1—C15122.1 (2)C2—C7—H7106.5
C10—C1—C11107.44 (18)C8—C7—H7106.5
C10—C1—C13102.75 (19)C12—C8—C9106.94 (18)
C11—C1—C13117.49 (19)C12—C8—C7109.72 (19)
C10—C1—C2110.52 (17)C9—C8—C7101.53 (18)
C11—C1—C2101.89 (18)C12—C8—Cl1113.15 (17)
C13—C1—C2116.58 (19)C9—C8—Cl1112.82 (17)
C3—C2—C7108.28 (18)C7—C8—Cl1111.97 (16)
C3—C2—C1122.1 (2)C10—C9—C8112.2 (2)
C7—C2—C1106.82 (18)C10—C9—Cl2125.0 (2)
C3—C2—H2106.2C8—C9—Cl2122.67 (17)
C7—C2—H2106.2C9—C10—C14135.0 (2)
C1—C2—H2106.2C9—C10—C1115.5 (2)
C2—C3—C4106.4 (2)C14—C10—C1109.45 (19)
C2—C3—H3A110.4C12—C11—C1113.08 (19)
C4—C3—H3A110.4C12—C11—Cl3125.46 (19)
C2—C3—H3B110.4C1—C11—Cl3120.99 (18)
C4—C3—H3B110.4C11—C12—C8114.1 (2)
H3A—C3—H3B108.6C11—C12—Cl4123.46 (19)
C5—C4—C3113.5 (2)C8—C12—Cl4122.24 (18)
C5—C4—H4A108.9O1—C13—N1125.4 (2)
C3—C4—H4A108.9O1—C13—C1126.9 (2)
C5—C4—H4B108.9N1—C13—C1107.7 (2)
C3—C4—H4B108.9O2—C14—N1124.7 (2)
H4A—C4—H4B107.7O2—C14—C10130.0 (2)
C4—C5—C6114.4 (2)N1—C14—C10105.3 (2)
C4—C5—H5A108.7N1—C15—C16110.9 (2)
C6—C5—H5A108.7N1—C15—H15A109.5
C4—C5—H5B108.7C16—C15—H15A109.5
C6—C5—H5B108.7N1—C15—H15B109.5
H5A—C5—H5B107.6C16—C15—H15B109.5
C7—C6—C5106.5 (2)H15A—C15—H15B108.1
C7—C6—H6A110.4C15—C16—H16A109.5
C5—C6—H6A110.4C15—C16—H16B109.5
C7—C6—H6B110.4H16A—C16—H16B109.5
C5—C6—H6B110.4C15—C16—H16C109.5
H6A—C6—H6B108.6H16A—C16—H16C109.5
C6—C7—C2108.29 (19)H16B—C16—H16C109.5
C6—C7—C8120.47 (19)
C10—C1—C2—C3−85.4 (2)C2—C1—C10—C14122.6 (2)
C11—C1—C2—C3160.6 (2)C10—C1—C11—C12−56.2 (3)
C13—C1—C2—C331.3 (3)C13—C1—C11—C12−171.3 (2)
C10—C1—C2—C739.8 (2)C2—C1—C11—C1260.0 (2)
C11—C1—C2—C7−74.1 (2)C10—C1—C11—Cl3131.25 (19)
C13—C1—C2—C7156.59 (19)C13—C1—C11—Cl316.1 (3)
C7—C2—C3—C463.4 (2)C2—C1—C11—Cl3−112.55 (19)
C1—C2—C3—C4−172.0 (2)C1—C11—C12—C85.1 (3)
C2—C3—C4—C5−52.7 (3)Cl3—C11—C12—C8177.23 (18)
C3—C4—C5—C649.3 (3)C1—C11—C12—Cl4−169.50 (17)
C4—C5—C6—C7−52.7 (3)Cl3—C11—C12—Cl42.6 (3)
C5—C6—C7—C262.9 (3)C9—C8—C12—C1150.1 (3)
C5—C6—C7—C8−172.4 (2)C7—C8—C12—C11−59.2 (3)
C3—C2—C7—C6−72.1 (2)Cl1—C8—C12—C11174.98 (19)
C1—C2—C7—C6154.62 (19)C9—C8—C12—Cl4−135.17 (19)
C3—C2—C7—C8155.98 (19)C7—C8—C12—Cl4115.5 (2)
C1—C2—C7—C822.7 (2)Cl1—C8—C12—Cl4−10.3 (3)
C6—C7—C8—C12−85.4 (3)C14—N1—C13—O1−178.0 (2)
C2—C7—C8—C1239.5 (2)C15—N1—C13—O15.3 (4)
C6—C7—C8—C9161.7 (2)C14—N1—C13—C10.7 (3)
C2—C7—C8—C9−73.4 (2)C15—N1—C13—C1−175.9 (2)
C6—C7—C8—Cl141.1 (3)C10—C1—C13—O1179.8 (3)
C2—C7—C8—Cl1166.01 (16)C11—C1—C13—O1−62.5 (3)
C12—C8—C9—C10−55.8 (2)C2—C1—C13—O158.8 (3)
C7—C8—C9—C1059.2 (2)C10—C1—C13—N11.1 (2)
Cl1—C8—C9—C10179.16 (17)C11—C1—C13—N1118.8 (2)
C12—C8—C9—Cl2128.65 (18)C2—C1—C13—N1−119.9 (2)
C7—C8—C9—Cl2−116.38 (18)C13—N1—C14—O2177.1 (2)
Cl1—C8—C9—Cl23.6 (3)C15—N1—C14—O2−6.2 (4)
C8—C9—C10—C14−177.9 (2)C13—N1—C14—C10−2.3 (3)
Cl2—C9—C10—C14−2.5 (4)C15—N1—C14—C10174.4 (2)
C8—C9—C10—C15.1 (3)C9—C10—C14—O26.4 (4)
Cl2—C9—C10—C1−179.49 (16)C1—C10—C14—O2−176.4 (2)
C11—C1—C10—C950.7 (3)C9—C10—C14—N1−174.2 (3)
C13—C1—C10—C9175.3 (2)C1—C10—C14—N12.9 (2)
C2—C1—C10—C9−59.6 (3)C13—N1—C15—C1692.3 (4)
C11—C1—C10—C14−127.04 (19)C14—N1—C15—C16−84.1 (3)
C13—C1—C10—C14−2.5 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7···O2i0.982.493.428 (3)161
C6—H6A···Cl4ii0.972.813.669 (3)147
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y−1/2, −z+1/2.

Experimental details

(I)(II)
Crystal data
Chemical formulaC16H15Cl4NO2C16H15Cl4NO2
Mr395.09395.09
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/c
Temperature (K)298298
a, b, c (Å)10.705 (17), 9.269 (12), 17.53 (3)10.937 (7), 9.228 (4), 17.100 (6)
β (°) 97.83 (13) 94.83 (4)
V (Å3)1723 (5)1719.7 (15)
Z44
Radiation typeMo KαMo Kα
µ (mm−1)0.690.70
Crystal size (mm)0.60 × 0.32 × 0.250.60 × 0.60 × 0.38
Data collection
DiffractometerNicolet P3 four-circle
diffractometer		Nicolet P3 four-circle
diffractometer
Absorption correctionψ scan
(North et al., 1968)		ψ scan
(North et al., 1968)
Tmin, Tmax0.606, 0.8410.567, 0.768
No. of measured, independent and
observed [I > 2σ(I)] reflections		5280, 5047, 2697 5269, 5043, 3191
Rint0.0360.023
(sin θ/λ)max (Å−1)0.7050.705
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.063, 0.159, 1.01 0.053, 0.134, 1.04
No. of reflections50475043
No. of parameters209209
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.59, −0.270.63, −0.33

Computer programs: Nicolet P3 Software (Nicolet, 1980), Nicolet P3 Software, RDNIC (Howie, 1980), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), SHELXL97 and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
C6—H6B···O2i0.972.533.434 (7)154
Symmetry code: (i) −x+1, −y+1, −z+1.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
C7—H7···O2i0.982.493.428 (3)161
C6—H6A···Cl4ii0.972.813.669 (3)147
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y−1/2, −z+1/2.
Table 1. Selected torsion angles (°) for (I)–(III). top
ParameterIIIIIIa
C10—C1—C2—C3-160.5 (3)-85.4 (2)-159.1 (4)
C11—C1—C2—C385.8 (4)160.6 (2)86.5 (4)
C13—C1—C2—C3-48.9 (4)31.3 (3)-48.3 (5)
C10—C1—C2—C768.6 (3)39.8 (2)69.5 (3)
C11—C1—C2—C7-45.1 (3)-74.1 (2)-44.9 (4)
C13—C1—C2—C7-179.7 (3)156.59 (19)-179.7 (3)
C1—C2—C7—C6-154.6 (3)154.62 (19)-155.5 (3)
C3—C2—C7—C667.8 (4)-72.1 (2)65.8 (4)
C1—C2—C7—C8-16.6 (3)22.7 (2)-18.0 (4)
C3—C2—C7—C8-154.1 (3)155.98 (19)-156.7 (3)
C2—C7—C8—C1268.7 (3)39.5 (2)69.7 (4)
C6—C7—C8—C12-159.6 (3)-85.4 (3)-158.8 (4)
C2—C7—C8—C9-43.9 (3)-73.4 (2)-44.1 (4)
C6—C7—C8—C987.7 (4)161.7 (2)87.4 (4)
Note a. The values given are for the enantiomer of the molecule selected as the asymmetric unit of the racemic structure described by McSweeney et al. (2005).
 

Acknowledgements

FG and CO thank Dublin City University for studentships.

References

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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Volume 61| Part 6| June 2005| Pages o369-o372
doi:10.1107/S0108270105010218
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