N,N′-bis(methoxycarbonylmethyl)-terephthalamide

Article abstract of DOI:10.1107/S0108270100014864

Molecules of the title compound, dimethyl N,N′-(1,4-benzene-dicarboxamido)diacetate, C₁₄H₁₆N₂O₆, lie on inversion centres and are hydrogen bonded along a single direction that runs parallel to the crystallograph

Full text of DOI:10.1107/S0108270100014864

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
0
N,N -Bis(methoxycarbonylmethyl)-
Figure 1
A view of (I) with the atom-numbering scheme for the non-H atoms.
Displacement ellipsoids are shown at the 50% probability level and H
atoms are drawn as circles with arbitrary radii.
terephthalamide
Elaine Armelin, Encarnaci o n Escudero, Lourdes Campos
and Jordi Puiggal Âõ *
ꢁ
structure (75 and � 145 , respectively; Crick & Rich, 1955).
Departament d'Enginyeria Qu Âõ mica, ETS d'Enginyeria Industrial de Barcelona,
Universitat Polit eÁ cnica de Catalunya, Diagonal 647, Barcelona 08028, Spain
Correspondence e-mail: puiggali@eq.upc.es
The molecular conformation is also characterized by the N1Ð
ꢁ
C4ÐC5ÐC6 torsion angle of 156.09 (13) , which clearly
ꢁ
deviates from 180 . Thus, a displacement of the planar amide
ꢁ
group out of the plane of the benzene ring (27 ) is produced.
This departure from a planar structure (favoured by resonance
Received 31 May 2000
Accepted 20 October 2000
0
Molecules of the title compound, dimethyl N,N -(1,4-benzene-
dicarboxamido)diacetate, C H N O , lie on inversion
1
4
16
2
6
centres and are hydrogen bonded along a single direction
that runs parallel to the crystallographic b axis. Glycine
residues adopt a conformation which deviates slightly from
that characteristic of the polyglycine II structure. An angle
ꢁ
close to 27 is found between the planar amide groups and the
plane of the aromatic ring.
Comment
Poly(ester amide)s derived from natural amino acids have
recently been suggested as a potential family of biodegradable
polymers (Paredes, Rodr õ guez-Gal a n & Puiggal õ , 1998;
Paredes, Rodr õ guez-Gal a n, Puiggal õ & Peraire, 1998). In order
to obtain data for the determination of these polymer struc-
tures, different model compounds have been solved (Urp õÂ et
al., 1998a,b, 1999). The title compound, (I), has been chosen
for the study of polymers derived from terephthalic acid,
glycine and different diols, since it may be a model for the
common sequence ±OCOCH NHCOC H CONHCH COO±.
2
6
4
2
The model molecule is shown in Fig. 1, and selected rotation
angles and hydrogen-bond geometry are reported in Tables 1
and 2, respectively.
The amide and ester groups and the benzene ring are
planar within experimental accuracy, with root-mean-square
distances of the atoms from the best planes de®ned by them
Ê
of 0.011, 0.034 and 0.014 A for C3/N1/C4/O3/C5, C1/O1/C2/
0
0
0
0
O2/C3 and C4/C5/C6/C7/C7 /C6 /C5 /C4 , respectively. The
molecule is centrosymmetric and consequently the torsion
angles of its two halves are equal but with opposite signs. The
glycine residues are characterized by the torsion angles '
(C2ÐC3ÐN1ÐC4) and (O1ÐC2ÐC3ÐN1), the values of
which are very close to those found in the polyglycine II
Figure 2
The crystal packing of (I) shown with views normal to (a) the ac and (b)
the bc plane. Hydrogen bonds are established along a single direction that
runs practically parallel to the a axis.
ꢀ
172 # 2001 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2001). C57, 172±173

organic compounds
energy of the conjugate system) can be explained by taking
into account a combination of two factors: (i) steric hindrances
between the H and O atoms of the amide groups and the
nearest H atoms of the aromatic ring; (ii) the establishment in
the crystal of intermolecular hydrogen bonds between the
Table 1
Selected torsion angles ( ).
ꢁ
N1ÐC4ÐC5ÐC6
C4ÐN1ÐC3ÐC2
156.09 (13)
65.2 (2)
N1ÐC3ÐC2ÐO1
� 152.04 (17)
amide groups of adjacent molecules. Similar values in the 20±
ꢁ
Table 2
Hydrogen-bonding geometry (A, ).
3
0 interval for the internal rotation angle have been found for
Ê
ꢁ
different model compounds of aromatic polyamides (Blake &
Small, 1972; Palmer & Brisse, 1980; Harkema & Gaymans,
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
2.08
DÁ Á ÁA
DÐHÁ Á ÁA
1
977) and poly(ester amide)s (Cesari et al., 1976). The mole-
i
N1ÐH1Á Á ÁO3
0.86
2.868 (2)
152
cular packing (Fig. 2) is characterized by the establishment of
hydrogen bonds along a single direction. A standard geometry
is found between the hydrogen-bonded molecules, which are
not shifted along the molecular axis direction. A twofold screw
axis parallel to the b axis relates the non-hydrogen-bonded
molecules of the unit cell. The aromatic rings of these two
molecules adopt a disposition close to perpendicular, with a
Symmetry codes: (i) x;1 ‡ y;z.
Re®nement
2
Re®nement on F
2
H-atom parameters constrained
2 2 2
2
R[F > 2ꢄ(F )] = 0.069
wR(F ) = 0.175
S = 1.491
o
w = 1/[ꢄ(F ) + (0.1P) ]
2 2
2
where P = (F
o c
+ 2F )/3
(Á/ꢄ)max < 0.001
Ê
distance of 5.13 A between the centers of the two rings. This
Ê
� 3
� 3
1172 re¯ections
102 parameters
Áꢅmax = 0.31 e A
Áꢅmin = � 0.29 e AÊ
geometry is in agreement with recent calculations on benzene
dimers (Chipot et al., 1996) that show the T-shaped disposition
to be more stable than the stacked one. In the same sense, a
T-shaped disposition of aromatic rings seems to be preferred
in proteins (Hunter et al., 1991).
H atoms were placed in calculated positions and re®ned riding on
Ê
the atom to which they are attached (NÐH = 0.86 A and CÐH =
Ê
.93±0.97 A), with a ®xed isotropic displacement parameter.
0
Data collection: CAD-4 Software (Kiers, 1994); cell re®nement:
CAD-4 Software; data reduction: local program; program(s) used to
solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to
re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
ORTEPII (Johnson, 1976).
Experimental
The title compound was synthesized by the reaction of a solution of
glycine methyl ester hydrochloride (0.02 mol) and triethylamine
This research was supported through CICYT grant MAT97/
013.
1
(0.04 mol) in chloroform (30 ml) with a solution of terephthaloyl
chloride (0.01 mol) in chloroform (20 ml), which was added slowly
while maintaining the temperature at 273 K. After 2 h at room
temperature, the solution was evaporated yielding a yellow powder
that was recrystallized from water (yield 75%, m.p. 435 K). Colorless
prismatic crystals were obtained by vapor diffusion (293 K) of a 91:9
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: DE1152). Services for accessing these data are
described at the back of the journal.
References
�
1
(
v/v) water/2-propanol solution (concentration 3.6 mg ml ) against
00% water used as precipitant.
Blake, C. C. F. & Small, R. W. H. (1972). Acta Cryst. B28, 2201±2206.
Cesari, M., Perego, G. & Melis, A. (1976). Eur. Polym. J. 12, 585±590.
Chipot, C., Jaffe, R., Maigret, B., Pearlman, D. A. & Kollman, P. A. (1996). J.
Am. Chem. Soc. 118, 11217±11224.
Crick, F. H. C. & Rich, A. (1955). Nature (London), 176, 780±781.
Harkema, S. & Gaymans, R. J. (1977). Acta Cryst. B33, 3609±3611.
Hunter, C. A., Singh, J., Thornton, J. M. (1991). J. Mol. Biol. 218, 837±850.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National
Laboratory, Tennessee, USA.
Kiers, C. (1994). CAD-4 Software. UNIX Version. Enraf±Nonius, Delft, The
Netherlands.
Palmer, A. & Brisse, F. (1980). Acta Cryst. B36, 1447±1452.
Paredes, N., Rodr õ guez-Gal a n, A. & Puiggal Âõ , J. (1998). J. Polym. Sci. Polym.
Chem. Ed. 36, 1271±1282.
Paredes, N., Rodr Âõ guez-Gal a n, A., Puiggal Âõ , J. & Peraire, C. (1998). J. Appl.
Polym. Sci. 69, 1537±1549.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of G oÈ tt-
ingen, Germany.
Urp Âõ , L., Rodr Âõ guez-Gal a n, A. & Puiggal õ , J. (1998a). Macromol. Chem. Phys.
199, 1167±1173.
Urp Âõ , L., Rodr Âõ guez-Gal a n, A. & Puiggal Âõ , J. (1998b). J. Chem. Crystallogr. 28,
605±610.
1
Crystal data
�
3
C
14
H
16
N O
2 6
D
x
= 1.363 Mg m
M
r
= 308.29
Monoclinic, P2
Cu Kꢁradiation
1
/a
Cell parameters from 20
re¯ections
Ê
a = 8.9889 (10) A
Ê
b = 4.977 (2) A
ꢁ
ꢂ= 8±35
Ê
� 1
c = 16.790 (4) A
ꢀ
ꢃ= 0.916 mm
T = 293 (2) K
ꢁ
3
= 90.900 (10)
Ê
V = 751.1 (4) A
Z = 2
Prism, colourless
0.20 Â 0.10 Â 0.05 mm
Data collection
ꢁ
Enraf±Nonius CAD-4 diffract-
ometer
ꢂmax = 65.77
h = � 10 ! 10
!
scans
k = 0 ! 5
2
1
1
237 measured re¯ections
172 independent re¯ections
029 re¯ections with I > 2ꢄ(I)
l = � 19 ! 19
3 standard re¯ections
frequency: 60 min
intensity decay: 0.5%
Urp Âõ , L., Rodr õ guez-Gal a n, A. & Puiggal õ , J. (1999). J. Chem. Crystallogr. 29,
1055±1059.
Rint = 0.031
ꢀ
Acta Cryst. (2001). C57, 172±173
Elaine Armelin et al.
14 16 2
C H N O
6
173