Diortho­benzeno­tetra(5′,2′ tetrazolo)[5′ (2) 2′ (6)]­cyclo­phane

Acta Cryst.(2001). E57, o195±o197 DOI: 101107/S1600536801001398 Richard N. Butleret al. C₂₈H₃₂N₁₆

o195

organic papers

Acta Crystallographica Section E Structure Reports Online

ISSN 1600-5368

Diorthobenzenotetra(5

_,2

_{-tetrazolo)[5}

_-(2)-2

-(6)]-cyclophane

Richard N. Butler,a_{John M. G.}

McGinley,b_{Mary F. Mahon,}b_*

Kieran C. Molloyb_{and Eithne P.}

NõÂBhraÂdaigha

a_{Department of Chemistry, University College,}

Galway, Ireland, andb_{Department of Chemistry,} University of Bath, Claverton Down, Bath BA2 7AY, England

Correspondence e-mail: chsmfm@bath.ac.uk

Key indicators Single-crystal X-ray study

T= 293 K

Mean(C±C) = 0.003 AÊ

Rfactor = 0.037

wRfactor = 0.098

Data-to-parameter ratio = 11.2

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2001 International Union of Crystallography Printed in Great Britain ± all rights reserved

The ®rst structure of the tetra-tetrazole macrocycle diortho-benzenotetra(50_,20_{-tetrazolo)[5}0_-(2)-20_{-(6)]cyclophane, C}

28H32

-N16, has been determined. The interior of the rectangular

cavity measuresca11.25.7 AÊ.

Comment

We have been interested for some time in the synthesis of compounds with multiple tetrazole fragments (Bethel et al., 1999; Bhandari et al., 1999; Butler et al., 1992; Butler & Fleming, 1997; Butler & NõÂBhraÂdaigh, 1994). One of us (RNB) has succeeded in generating tetratetrazole macrocyles of general formula (I) which include an apparent cavity of vari-able dimensions tailored by both the length and ¯exibility of the bridging groups Xand Y (Butler & NõÂBhraÂdaigh, 1994; Butleret al., 1992; Butler & Fleming, 1997). Such macrocycles represent an extension of other work which has led to the isolation of polyazole macrocycles containing pyrazole (Tarragoet al., 1988) and triazole (Galet al., 1985; Cabezonet al., 1995).

The structure of diorthobenzenotetra(50_,20 -tetrazolo)-[50_-(2)-20_{-(6)]cyclophane [(I), X= 1,2±C}

6H4, Y = (CH2)6] is

now reported (Fig. 1). The molecule is centrosymmetric about the inversion centre at 1

2,12,12, which is intrinsic in the

space-group symmetry. Of central importance is the rectangular nature of the macrocyle cavity, which measuresca11.228 (3) (C14ÐN50_{) by 5.678 (4) AÊ (C8ÐC8}0_{), as this is the ®rst} structure of a macrocycle containing four sub-tetrazole rings surrounding such a feature. Cyclophanes with two tetrazole rings have been reported (Ried & Aboul-Fetouh, 1988; Riedet al., 1989; Bethelet al., 1999), but such systems do not consti-tute a cavity. The central void depicted in Fig. 1 is more apparent than real, as a space-®lling representation (Fig. 2) illustrates. While there is clearly a void channel running parallel to, and between, the (CH2)6chains, the orientations of

the potentially coordinating tetrazole units are orthogonal to this channel. Much smaller voids are evident between pairs of tetrazoles attached to the same C6H4 unit (Fig. 2), though

nitrogen lone pairs from each heterocycle are approximately

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o196

at right angles to each other (see below) and are not oriented for concerted metal-ion complexation.

Of the two unique tetrazoles, one is essentially coplanar with the phenyl group to which it is attached (torsion angle between ring planes 9.58_{), while the other is approximately} orthogonal (torsion angle 97.51_{). This allows} symmetry-related pairs of tetrazoles to adopt cofacial orientations with respect to each other across opposite sides of the rectangle. In other structures containing tetrazoles bonded at the ortho positions of a six-membered aromatic system, the two heterocycles are also found to be twisted with respect to the central ring (Bethel et al., 1999). In one case, 2-(1,2)benzo-1(5,1),3(5,2)-bistetrazolocyclodecaphane, the twist angles (7.7 and 85.6_{) are very similar to those found in the title}

compound (Ried & Aboul-Fetouh, 1988). Overall the macrocyle exists in a chair conformation with the -(CH2)6

-linkages adopting a surprisingly rigid linear conformation (Fig. 1). Such a structure has been predicted by energy minimiza-tion calculaminimiza-tions for the more rigid analogue of the title compound, (I) (X = 1,3±C6H4, Y = 1,4±C6H4), but was not

anticipated for the title compound (Butler & Fleming, 1997).

Experimental

The title compound was synthesized according to the literature method of Butler & NõÂBhraÂdaigh (1994). Crystals suitable for X-ray diffraction were grown from dichloromethane/pentane (1:1).

Crystal data

C28H32N16

Mr= 592.70

Triclinic,P1 a= 7.170 (2) AÊ b= 10.241 (3) AÊ c= 10.729 (3) AÊ = 77.25 (3) = 74.89 (3) = 73.47 (3)

V= 719.9 (4) AÊ3

Z= 1

Dx= 1.367 Mg mÿ3

MoKradiation Cell parameters from 25

re¯ections = 13.9±17.7 = 0.09 mmÿ1

T= 293 (2) K Block, colourless 0.350.300.30 mm

Data collection

Enraf±Nonius CAD-4 diffract-ometer

/2scans

2441 measured re¯ections 2238 independent re¯ections 1674 re¯ections withI> 2(I) Rint= 0.010

max= 24.0

h= 0!8 k=ÿ11!11 l=ÿ11!12 1 standard re¯ection

every 80 re¯ections frequency: 150 min intensity decay: none

Re®nement

Re®nement onF2

R[F2_{> 2(F}2_{)] = 0.037}

wR(F2_{) = 0.098}

S= 1.19 2238 re¯ections 200 parameters

H-atom parameters constrained

w= 1/[2_(F

o2) + (0.0714P)2

+ 0.0022P]

whereP= (Fo2+ 2Fc2)/3

(/)max< 0.001

max= 0.17 e AÊÿ3

min=ÿ0.13 e AÊÿ3

Extinction correction:SHELXL93 Extinction coef®cient: 0.061 (7)

It was possible to re®ne all H-atom positions in this crystal structure. However, as `free' re®nement yielded a ®nal position which was close (within the bounds of experimental error) to the calculated positions, we ultimately re®ned the H atoms riding on their relevant parent atoms.

Data collection: CAD-4-PC Software (Enraf±Nonius, 1992); cell re®nement:CELDIMinCAD-4-PC Software;data reduction:XCAD

(McArdle & Higgins, 1995); program(s) used to solve structure:

SHELXS86 (Sheldrick, 1990); program(s) used to re®ne structure:

SHELXL93 (Sheldrick, 1993); molecular graphics: ORTEX

(McArdle, 1995).

References

Bethel, P. A., Hill, M. S., Mahon, M. F. & Molloy, K. C. (1999).J. Chem. Soc. Perkin Trans.I, pp. 3507±3514.

Bhandari, S., Mahon, M. F. & Molloy, K. C. (1999).J. Chem. Soc. Dalton Trans. pp. 1951±1956.

Butler, R. N. & Fleming, A. F. M. (1997).J. Heterocycl. Chem.34, 691±693. Butler, R. N. & NõÂBhraÂdaigh, E. P. (1994).J. Chem. Res.(S), pp. 148±149. Figure 1

ORTEX(McArdle, 1995) plot of the asymmetric unit of

diorthobenzeno-tetra(50_,20_{-tetrazolo)[5}0_-(2)-20_{-(6)]cyclophane showing the labelling}

scheme. Ellipsoids are represented at the 30% probability level. Primed

labelled atoms are related to unprimed labelled atoms by the 1ÿx,

1ÿy, 1ÿzsymmetry operation.

Figure 2

Space-®lling stereoview of diorthobenzenotetra(50_,20_{-tetrazolo)[5}0_-(2)-20

Butler, R. N., Quinn, K. F. & Welke, B. (1992).J. Chem. Soc. Chem. Commun. pp. 1481±1482.

Cabezon, B., Rodriguez-Morgade, S. & Torres, T. (1995).J. Org. Chem.60, 1872±1874.

Enraf±Nonius. (1992).CAD-4-PC Software. Version 1.1. Enraf±Nonius, Delft, The Netherlands.

Gal, M., Tarrago, G., Steel, P. & Marzin, C. (1985).Nouv. J. Chim.9, 617±620.

McArdle, P. (1995).J. Appl. Cryst.28, 65.

McArdle, P. & Higgins, T. (1995).XCAD. University College, Galway, Ireland. Ried, W. & Aboul-Fetouh, S. (1988).Tetrahedron,44, 3399±3404.

Ried, W., Lee, CÐH. & Bats, J. W. (1989).Liebigs Ann. Chem.pp. 497±500. Sheldrick, G. M. (1990).Acta Cryst.A46, 467±473.

Sheldrick, G. M. (1993).SHELXL93. University of GoÈttingen, Germany. Tarrago, G., Zidane, I., Marzin, C. & Tep, A. (1988).Tetrahedron,44, 91±100.

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Acta Cryst. (2001). E57, o195–o197 [doi:10.1107/S1600536801001398]

Diorthobenzenotetra(5

′

,2

′

-tetrazolo)[5

′

-(2)-2

′

-(6)]cyclophane

Richard N. Butler, John M. G. McGinley, Mary F. Mahon, Kieran C. Molloy and Eithne P.

N

í

Bhr

á

daigh

S1. Comment

We have been interested for some time in the synthesis of compounds with multiple tetrazole fragments (Bethel et al.,

1999; Bhandari et al., 1999; Butler et al., 1992; Butler & Fleming, 1997; Butler & NíBhrádaigh, 1994). One of us (RNB)

has succeeded in generating tetratetrazole macrocyles of general formula (I) which include an apparent cavity of variable

dimensions tailored by both the length and flexibility of the bridging groups X and Y (Butler & NíBhrádaigh, 1994;

Butler et al., 1992; Butler & Fleming, 1997). Such macrocycles represent an extension of other work which has led to the

isolation of polyazole macrocycles containing pyrazole (Tarrago et al., 1988) and triazole (Gal et al., 1985; Cabezon et

al., 1995).

The structure of diorthobenzenotetra(5′,2′-tetrazolo)[5′-(2)–2′-(6)]cyclophane [(I), X = 1,2-C6H4, Y = (CH2)6] is now

reported (Fig. 1). The molecule is centrosymmetric about the inversion centre at 1/2, 1/2, 1/2, which is intrinsic in the

space-group symmetry. Of central importance is the rectangular nature of the macrocyle cavity, which measures ca

11.228 (3) (C14—N5′) by 5.678 (4) Å (C8—C8′), which is the first structure of a macrocycle containing four

sub-tetrazole rings surrounding such a feature. Cyclophanes with two sub-tetrazole rings have been reported (Ried &

Aboul-Fetouh, 1988; Ried et al., 1989; Bethel et al., 1999), but such systems do not constitute a cavity. The central void

depicted in Fig. 1 is more apparent than real, as a space-filling representation (Fig. 2) illustrates. While there is clearly a

void channel running parallel to, and between, the (CH2)6 chains, the orientations of the potentially coordinating tetrazole

units are orthogonal to this channel. Much smaller voids are evident between pairs of tetrazoles attached to the same C6H4

unit (Fig. 2), though nitrogen lone pairs from each heterocycle are approximately at right angles to each other (see below)

and are not oriented for concerted metal-ion complexation.

Of the two unique tetrazoles, one is essentially coplanar with the phenyl group to which it is attached (torsion angle

between ring planes 9.58°), while the other is approximately orthogonal (torsion angle 97.51°). This allows

symmetry-related pairs of tetrazoles to adopt cofacial orientations with respect to each other across opposite sides of the rectangle.

In other structures containing tetrazoles bonded at the ortho positions of a six-membered aromatic system, the two

heterocycles are also found to be twisted with respect to the central ring (Bethel at al., 1999). In one case,

2-(1,2)benzo-1(5,1),3(5,2)-bistetrazolocyclodecaphane, the twist angles (7.7 and 85.6°) are very similar to those found in

the title compound (Ried & Aboul-Fetouh, 1988). Overall the macrocyle exists in a chair conformation with the -(CH2)6–

linkages adopting a surprisingly rigid linear conformation (Fig. 1). Such a structure has been predicted by energy

minimization calculations for the more rigid analogue of the title compound, (I) (X = 1,3-C6H4, Y = 1,4-C6H4), but was

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S2. Experimental

The title compound was synthesized according to the literature method of Butler & NiBhradaigh (1994). Crystals suitable

for X-ray diffraction were grown from dichloromethane/pentane (1:1).

S3. Refinement

It was possible to positionally refine all H-atom positions in this crystal structure. However, as `free′ refinement yielded a

final position which was close (within the bounds of experimental error) to the calculated positions, we ultimately refined

the H atoms riding on their relevant parent atoms.

Figure 1

ORTEX plot of the asymmetric unit of diorthobenzenotetra(5′,2′-tetrazolo)[5′-(2)–2′-(6)]cyclophane showing the labelling scheme. Ellipsoids are represented at the 30% probability level. Primed labelled atoms are related to unprimed labelled

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Figure 2

Space-filling stereoview of diorthobenzenotetra(5′,2′-tetrazolo)[5′-(2)–2′-(6)]cyclophane showing the restricted nature of

the macrocycle cavity.

(93kcm4)

Crystal data

C28H32N16 Mr = 592.70 Triclinic, P1

a = 7.170 (2) Å

b = 10.241 (3) Å

c = 10.729 (3) Å

α = 77.25 (3)°

β = 74.89 (3)°

γ = 73.47 (3)°

V = 719.9 (4) Å3

Z = 1

F(000) = 312

Dx = 1.367 Mg m−3

Mo Kα radiation, λ = 0.71069 Å Cell parameters from 25 reflections

θ = 13.9–17.7°

µ = 0.09 mm−1 T = 293 K Block, colourless 0.35 × 0.30 × 0.30 mm

Data collection

Enraf-Nonius CAD-4 diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

θ/2θ scans

2441 measured reflections 2238 independent reflections 1674 reflections with I > 2σ(I)

Rint = 0.010

θmax = 24.0°, θmin = 2.1° h = 0→8

k = −11→11

l = −11→12

1 standard reflections every 80 reflections intensity decay: none

Refinement

Refinement on F2 Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.037} wR(F2_{) = 0.098} S = 1.08 2238 reflections 200 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained

w = 1/[σ2_(F

o2) + (0.0714P)2 + 0.0022P] where P = (Fo2 + 2Fc2)/3

(Δ/σ)max < 0.001 Δρmax = 0.17 e Å−3 Δρmin = −0.13 e Å−3

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Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2₎

x y z Uiso*/Ueq

N1 0.2292 (2) 0.31148 (15) 0.60411 (13) 0.0527 (4)

N2 0.2397 (2) 0.43564 (15) 0.53809 (14) 0.0559 (4)

N3 0.2452 (2) 0.43014 (14) 0.41642 (14) 0.0498 (4)

N4 0.2409 (2) 0.30851 (14) 0.39627 (13) 0.0501 (4)

N5 0.8191 (2) 0.87060 (13) 0.04860 (12) 0.0450 (4)

N6 0.7094 (2) 0.93678 (14) 0.14675 (13) 0.0456 (4)

N7 1.0277 (2) 0.86172 (15) 0.15889 (13) 0.0492 (4)

N8 1.0089 (2) 0.8249 (2) 0.05300 (13) 0.0516 (4)

C1 0.2314 (2) 0.0877 (2) 0.54015 (15) 0.0398 (4)

C2 0.2699 (2) 0.0224 (2) 0.4327 (2) 0.0477 (4)

H2 0.2921 0.0728 0.3490 0.057*

C3 0.2757 (3) −0.1152 (2) 0.4474 (2) 0.0547 (5)

H3 0.2993 −0.1565 0.3739 0.066*

C4 0.2469 (3) −0.1926 (2) 0.5705 (2) 0.0556 (5)

H4 0.2513 −0.2859 0.5806 0.067*

C5 0.2115 (2) −0.1294 (2) 0.6784 (2) 0.0500 (5)

H5 0.1941 −0.1815 0.7614 0.060*

C6 0.2014 (2) 0.0102 (2) 0.6658 (2) 0.0408 (4)

C7 0.2308 (2) 0.2356 (2) 0.51581 (14) 0.0408 (4)

C8 0.2703 (3) 0.5443 (2) 0.3086 (2) 0.0582 (5)

H8A 0.2363 0.6298 0.3435 0.070*

H8B 0.1807 0.5534 0.2516 0.070*

C9 0.4837 (3) 0.5195 (2) 0.2303 (2) 0.0549 (5)

H9A 0.5718 0.5112 0.2881 0.066*

H9B 0.5173 0.4326 0.1981 0.066*

C10 0.5207 (3) 0.6315 (2) 0.1161 (2) 0.0547 (5)

H10A 0.4839 0.7194 0.1471 0.066*

H10B 0.4380 0.6376 0.0555 0.066*

C11 0.7370 (3) 0.6029 (2) 0.0461 (2) 0.0552 (5)

H11A 0.7743 0.5116 0.0220 0.066*

H11B 0.8171 0.6014 0.1069 0.066*

C12 0.7894 (3) 0.7052 (2) −0.0763 (2) 0.0589 (5)

H12A 0.9314 0.6781 −0.1116 0.071*

H12B 0.7215 0.6990 −0.1413 0.071*

C13 0.7366 (3) 0.8532 (2) −0.0557 (2) 0.0529 (5)

H13A 0.7864 0.9092 −0.1364 0.063*

H13B 0.5929 0.8859 −0.0345 0.063*

C14 0.1567 (2) 0.0712 (2) 0.78545 (14) 0.0401 (4)

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

N1 0.0734 (10) 0.0496 (9) 0.0382 (8) −0.0257 (7) −0.0058 (7) −0.0059 (7)

N2 0.0742 (11) 0.0500 (9) 0.0452 (9) −0.0238 (7) −0.0042 (7) −0.0092 (7)

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N4 0.0668 (10) 0.0451 (8) 0.0401 (8) −0.0198 (7) −0.0110 (7) −0.0024 (6)

N5 0.0532 (9) 0.0438 (8) 0.0376 (7) −0.0147 (6) −0.0107 (6) −0.0004 (6)

N6 0.0470 (8) 0.0505 (8) 0.0393 (8) −0.0126 (6) −0.0094 (6) −0.0056 (6)

N7 0.0461 (8) 0.0565 (9) 0.0438 (8) −0.0109 (7) −0.0097 (6) −0.0069 (7)

N8 0.0498 (9) 0.0584 (9) 0.0445 (8) −0.0114 (7) −0.0075 (6) −0.0086 (7)

C1 0.0382 (9) 0.0440 (9) 0.0388 (9) −0.0127 (7) −0.0091 (7) −0.0047 (7)

C2 0.0542 (10) 0.0520 (10) 0.0397 (9) −0.0167 (8) −0.0118 (7) −0.0057 (7)

C3 0.0610 (11) 0.0540 (11) 0.0548 (11) −0.0132 (8) −0.0148 (8) −0.0180 (9)

C4 0.0587 (12) 0.0410 (9) 0.0698 (13) −0.0123 (8) −0.0179 (9) −0.0086 (9)

C5 0.0524 (10) 0.0464 (10) 0.0494 (11) −0.0152 (8) −0.0125 (8) 0.0025 (8)

C6 0.0357 (8) 0.0437 (9) 0.0431 (9) −0.0118 (7) −0.0097 (7) −0.0023 (7)

C7 0.0406 (9) 0.0472 (9) 0.0364 (9) −0.0156 (7) −0.0064 (7) −0.0056 (7)

C8 0.0745 (13) 0.0425 (10) 0.0513 (11) −0.0182 (8) −0.0058 (9) 0.0017 (8)

C9 0.0591 (11) 0.0491 (10) 0.0564 (11) −0.0204 (8) −0.0122 (9) 0.0017 (8)

C10 0.0612 (11) 0.0477 (10) 0.0518 (11) −0.0154 (8) −0.0087 (8) −0.0021 (8)

C11 0.0607 (12) 0.0470 (10) 0.0565 (11) −0.0173 (8) −0.0059 (9) −0.0079 (8)

C12 0.0685 (12) 0.0636 (12) 0.0470 (10) −0.0250 (10) −0.0031 (9) −0.0126 (9)

C13 0.0689 (12) 0.0566 (11) 0.0384 (9) −0.0233 (9) −0.0188 (8) 0.0014 (8)

C14 0.0434 (9) 0.0410 (8) 0.0349 (8) −0.0148 (7) −0.0093 (7) 0.0031 (7)

Geometric parameters (Å, º)

N1—N2 1.324 (2) C1—C7 1.479 (2)

N1—C7 1.347 (2) C2—C3 1.372 (2)

N2—N3 1.309 (2) C3—C4 1.380 (3)

N3—N4 1.320 (2) C4—C5 1.381 (2)

N3—C8 1.467 (2) C5—C6 1.388 (2)

N4—C7 1.329 (2) C6—C14 1.472 (2)

N5—N8 1.318 (2) C8—C9 1.522 (2)

N5—N6 1.329 (2) C9—C10 1.506 (2)

N5—C13 1.458 (2) C10—C11 1.512 (2)

N6i_{—C14 1.323 (2) C11—C12 1.524 (3)}

N7—N8 1.322 (2) C12—C13 1.506 (3)

N7i_{—C14 1.352 (2) C14}i_{—N6 1.323 (2)}

C1—C2 1.387 (2) C14i_{—N7 1.352 (2)}

C1—C6 1.403 (2)

N2—N1—C7 106.1 (1) C3—C4—C5 119.0 (2)

N3—N2—N1 106.1 (1) C4—C5—C6 121.6 (2)

N2—N3—N4 114.2 (1) C5—C6—C1 118.9 (2)

N2—N3—C8 123.7 (1) C5—C6—C14 118.5 (1)

N4—N3—C8 122.0 (1) C1—C6—C14 122.7 (1)

N3—N4—C7 102.0 (1) N4—C7—N1 111.8 (1)

N8—N5—N6 113.9 (1) N4—C7—C1 121.3 (1)

N8—N5—C13 123.3 (1) N1—C7—C1 126.9 (1)

N6—N5—C13 122.8 (1) N3—C8—C9 110.8 (2)

C14i_{—N6—N5 101.9 (1) C10—C9—C8 114.0 (2)}

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N5—N8—N7 106.0 (1) C10—C11—C12 115.7 (2)

C2—C1—C6 118.9 (1) C13—C12—C11 114.9 (2)

C2—C1—C7 117.9 (1) N5—C13—C12 112.4 (2)

C6—C1—C7 123.2 (1) N6i_—C14—N7i _{112.1 (1)}

C3—C2—C1 121.3 (2) N6i_{—C14—C6 124.1 (1)}

C2—C3—C4 120.4 (2) N7i_{—C14—C6 123.8 (1)}