4,5-Dibromo-phthalimide forms two centrosymmetric dimers, one linked by C - H...O hydrogen bonds and one by N - H...O hydrogen bonds

Article abstract of DOI:10.1107/S0108270107005239

In the title compound [also called 5,6-dibromo-isoindole-1,3(2H)-dione], C8H3Br2NO2, there are two planar mol-ecules in the asymmetric unit. They both form inversion dimers, one via N - H...O links and one via short near-linear C - H...O links. The dimers

Full text of DOI:10.1107/S0108270107005239

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
interaction (Taylor & Kennard, 1982; Desiraju & Steiner,
1999). An R22(10) supramolecular ring motif (Bernstein et al.,
1995) arises. For the C9 species, two more conventional, `hard',
NÐHÁ Á ÁO bonds fuse the dimeric pair of molecules together.
The supramolecular motif that results is an R22(8) loop.
Adjacent C1 and C9 dimers are then linked by the N1Ð
H1Á Á ÁO4 bond, resulting in molecular tapes propagating in
[210].
ISSN 0108-2701
4,5-Dibromophthalimide forms two
centrosymmetric dimers, one linked
by CÐHÁ Á ÁO hydrogen bonds and
one by NÐHÁ Á ÁO hydrogen bonds
A PLATON (Spek, 2003) analysis of (I) identi®ed two short
BrÁ Á ÁO interactions, compared with the Bondi (1964) van der
Ê
Waals separation of 3.37 A for these atoms. The close
iii
Ê
Br1Á Á ÁO3 separation of 3.209 (6) A probably correlates with
the N1ÐH1Á Á ÁO4 hydrogen bond linking the molecules into
Craig Williamson and William T. A. Harrison*
chains (see Fig. 2). The signi®cance of the second short
y, z] of
3.117 (6) A, which occurs between adjacent [110] chains, is less
contact, Br3Á Á ÁO1iv [symmetry code: (iv) x, 1
Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen
AB24 3UE, Scotland
Ê
obvious. A short Br4Á Á ÁBr2iv contact of 3.59017 (14) A (the
Ê
Correspondence e-mail: w.harrison@abdn.ac.uk
Ê
contact radius is 3.7 A) is also apparent. Any ꢀ±ꢀ stacking
Received 30 January 2007
Accepted 31 January 2007
Online 17 February 2007
In the title compound [also called 5,6-dibromoisoindole-
1,3(2H)-dione], C8H3Br2NO2, there are two planar molecules
in the asymmetric unit. They both form inversion dimers, one
via NÐHÁ Á ÁO links and one via short near-linear CÐHÁ Á ÁO
links. The dimers are then linked into chains by further NÐ
HÁ Á ÁO hydrogen bonds.
Comment
The title compound, (I), was prepared as an intermediate en
route to potential novel chromophores. This compound was
®rst reported by Hanack & Stihler (2000).
Figure 1
A view of (I), showing 50% probability displacement ellipsoids (H atoms
are drawn as small spheres of arbitrary radii). The NÐHÁ Á ÁO hydrogen
bond is shown as a double-dashed line. The C14ÐH14 group appears to
be well aligned to form a CÐHÁ Á ÁO interaction to O1 (CÐHÁ Á ÁO =
ꢀ
Ê
174 ), but the HÁ Á ÁO separation of 2.80 A is longer than the Bondi (1964)
Ê
contact distance of 2.72 A, suggesting that, at best, this is a very weak
interaction.
All the geometrical parameters for (I) (Fig. 1) lie within
their expected ranges (Allen et al., 1995). There are two
molecules in the asymmetric unit of (I); both are essentially
Ê
¯at, with an r.m.s. deviation from the mean plane of 0.017 A
Ê
for the molecule containing C1 and 0.012 A for the molecule
containing C9. The dihedral angle between the two molecules
is 7.96 (16)ꢀ. The geometries of the six- and ®ve-membered
rings in (I) are not signi®cantly different from those in
phthalimide, (II) (Zakaria et al., 2002), with the exception of
Ê
the C1ÐC2 and C9ÐC10 bonds [mean = 1.414 (9) A], which
Ê
are slightly longer than the equivalent bond of 1.387 (2) A in
(II), perhaps due to steric repulsion between the ortho Br
atoms.
The crystal packing (Fig. 2) for (I) results in hydrogen-
bonded inversion dimers for both molecules (Table 1). For the
molecule containing C1, two strong near-linear C6ÐH6Á Á ÁO2i
(see Table 1 for symmetry codes) interactions are the linking
Figure 2
Detail of the packing of (I), showing part of a [110] tape of dimers linked
by CÐHÁ Á ÁO and NÐHÁ Á ÁO hydrogen bonds (40% probability
displacement ellipsoids; H atoms involved in hydrogen bonding are
drawn as small spheres of arbitrary radii and other H atoms have been
omitted). The hydrogen bonds are shown as double-dashed lines. The
short Br1Á Á ÁO3iii separation of 3.209 (6) A is discussed in the Comment.
Ê
Ê
bonds. The HÁ Á ÁO separation of 2.36 A implies a strong
[Symmetry codes as in Table 1; additionally (iii) x 2, y 1, z.]
Acta Cryst. (2007). C63, o185±o186
DOI: 10.1107/S0108270107005239
# 2007 International Union of Crystallography o185

organic compounds
Table 1
Hydrogen-bond geometry (A, ).
effects in (I) must be exceedingly weak, with a minimum ring-
Ê
centroid separation of 4.12 A.
ꢀ
Ê
The crystal structure of (II) with one asymmetric molecule
(Zakaria et al., 2002) also shows chains of molecules linked by
NÐHÁ Á ÁO and CÐHÁ Á ÁO intermolecular interactions, but the
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C6ÐH6Á Á ÁO2i
N1ÐH1Á Á ÁO4
N2ÐH2Á Á ÁO3ii
0.93
0.86
0.86
2.36
1.95
2.04
3.274 (9)
2.793 (8)
2.902 (8)
167
167
175
Ê
CÐHÁ Á ÁO bonds in (II) (mean HÁ Á ÁO = 2.55 A) are much
weaker than those in (I). Although inversion-generated loops
featuring CÐHÁ Á ÁO and NÐHÁ Á ÁO interactions are present,
the chain and overall structures of (I) and (II) are quite
different.
Symmetry codes: (i) x; y; z ‡ 1; (ii) x ‡ 2; y ‡ 1; z ‡ 1.
All H atoms were placed in calculated positions, with CÐH
Ê
Ê
distances of 0.93 A and NÐH distances of 0.86 A, and re®ned as
riding, with Uiso(H) values of 1.2Ueq(carrier).
Experimental
Data collection: SMART (Bruker, 1999); cell re®nement: SAINT
(Bruker, 1999); data reduction: SAINT; program(s) used to solve
structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
ORTEP-3 (Farrugia, 1997); software used to prepare material for
publication: SHELXL97.
Rather than the published method of Hanack & Stihler (2000), a
modi®ed Wohrle (Wohrle et al., 1993) synthesis was used to prepare
(I). Dibromophthalic anhydride and excess formamide were heated
with stirring, at 413 K, without solvent for 5 h. The solution was
cooled and ®ltered, and the residue was washed with cold water. The
crude product was recrystallized (50:50 v/v, EtOH±H2O) and dried
overnight in a desiccator (P2O5). Slow crystallization from dichloro-
methane yielded colourless blocks of (I) (yield 66%; m.p. 508±513 K).
Analysis found: C 31.4, H 0.9, N 4.4, Br 52.1%; C8H3Br2NO2 requires:
C 31.5, H 1.0, N 4.6, Br 52.4%
The authors thank M. John Plater for helpful discussions.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GD3087). Services for accessing these data are
described at the back of the journal.
Crystal data
3
Ê
C8H3Br2NO2
Mr = 304.94
Triclinic, P1
a = 6.7725 (6) A
b = 11.0759 (10) A
V = 899.08 (14) A
Z = 4
3
Dx = 2.253 Mg m
Mo Kꢁ radiation
Ê
1
Ê
Ê
ꢄ = 8.98 mm
T = 293 (2) K
References
c = 12.3543 (10) A
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Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
ꢁ = 101.734 (2)ꢀ
ꢂ = 91.725 (2)ꢀ
ꢃ = 97.031 (2)ꢀ
Block, colourless
0.34 Â 0.29 Â 0.11 mm
Data collection
Bruker SMART1000 CCD
diffractometer
! scans
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
Tmin = 0.076, Tmax = 0.373
5395 measured re¯ections
3154 independent re¯ections
1994 re¯ections with I > 2ꢅ(I)
Rint = 0.034
ꢆmax = 25.1ꢀ
Re®nement
È
Gottingen, Germany.
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Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.047
wR(F2) = 0.116
S = 0.91
3154 re¯ections
235 parameters
H-atom parameters constrained
w = 1/[ꢅ2(F2o) + (0.0694P)2]
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max < 0.001
Taylor, R. & Kennard, O. (1982). J. Am. Chem. Soc. 104, 5063±5070.
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(Stuttgart), pp. 194±196.
Zakaria, C. M., Low, J. N. & Glidewell, C. (2002). Acta Cryst. C58, o9±
o10.
3
Ê
Áꢇmax = 0.96 e A
3
Ê
0.68 e A
Áꢇmin
=
ꢁ
o186 Williamson and Harrison
C8H3Br2NO2
Acta Cryst. (2007). C63, o185±o186