Hydrogen-bonded sheets in benzyl-methyl-ammonium hydrogen maleate

Article abstract of DOI:10.1107/S0108270107040450

In the title compound, C8H12N⁺·C4H3O4 ^-, there is a short and almost linear but asymmetric O - H...O hydrogen bond in the anion. The ions are linked into C 2 ²(6) chains by two short and nearly linear N - H...O hydrogen bonds and the chains are further weakly linked into sheets by a single C - H...O hydrogen bond. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107040450

organic compounds
C11±C16 and C17/N17/C18 is 80.07 (13)ꢀ, and the dihedral
angle between the C11±C16 plane and the best plane through
atoms C11/C17/N17/C18 is 81.41 (13)ꢀ.
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
Hydrogen-bonded sheets in benzyl-
methylammonium hydrogen maleate
Lynay Santacruz,a Rodrigo Abonia,a Justo Cobo,b John N.
Lowc and Christopher Glidewelld*
a
Â
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Grupo de Investigacion de Compuestos Heterociclõcos, Departamento de Quõmica,
b
Â
Â
Universidad de Valle, AA 25360, Colombia, Departamento de Quõmica Inorganica
y Organica, Universidad de Jaen, 23071 Jaen, Spain, cDepartment of Chemistry,
University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and
dSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
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There is a short and nearly linear OÐHÁ Á ÁO hydrogen bond
within the anion of (I) (Table 2) and the CÐO distances are
fully consistent with the location of the H atom in this
hydrogen bond, as deduced from difference maps. It is inter-
esting to compare the location of the hydrogen-bonded H
atom in the anion in salt (I) with that in some related hydrogen
maleate salts derived from simple amines, such as the
methylammonium and dimethylammonium salts (Madsen &
Larsen, 1998), the dicyclohexylammonium salt (Ng et al.,
Received 18 July 2007
Accepted 14 August 2007
Online 1 September 2007
In the title compound, C8H12N+ÁC4H3O4 , there is a short and
almost linear but asymmetric OÐHÁ Á ÁO hydrogen bond in the
anion. The ions are linked into C22(6) chains by two short and
nearly linear NÐHÁ Á ÁO hydrogen bonds and the chains are
further weakly linked into sheets by a single CÐHÁ Á ÁO
hydrogen bond.
Ï
1991), the tetramethylammonium salt (Drobez et al., 1985) and
the salts derived from some heteroaromatic diamines (Bowes
et al., 2003).
For methylammonium hydrogen maleate, the systematic
absences permitted a choice of space group, viz. Pna21 or
Pnam (a nonstandard setting of Pnma). The sites of all of the
non-H atoms were consistent with Pnam and the only atoms
whose positions could deviate from Pnam were the hydrogen-
bonded H atoms in the two independent anions; the preferred
model, in space group Pnam, had each of these H atoms
Comment
We report here the molecular and supramolecular structure of
benzylmethylammonium hydrogen maleate, (I), and we brie¯y
compare the supramolecular aggregation in (I) with that in
hydrogen maleate salts of some other secondary amines. The
compound was obtained during an attempt to prepare
ꢀ-(benzylmethylamino)succinic anhydride, (II) (see scheme),
for use as an intermediate in the synthesis of new fused
heterocyclic systems. Synthetic targets potentially accessible
from intermediates of type (II) include amino-substituted
phthalazines, which show activity as inhibitors of speci®c
enzymes, such as human liver aldehyde oxidase (Beedham et
al., 1995) and superoxide dismutase (Rodriguez-Ciria et al.,
2007), as well as activity against seizures induced by electro-
shock (Sivakumar et al., 2002), and fused 1,3-diazepines, which
show activity against the hepatitis-B and hepatitis-C viruses
(Zhang et al., 2005). The intended synthesis of (II) involved a
Michael-type reaction between benzylmethylamine and
maleic anhydride, but evidently hydrolysis occurred during
this procedure so that compound (I) was obtained instead,
albeit in low yield. A quantitative yield of compound (I) was
subsequently obtained from the direct reaction of benzyl-
methylamine and maleic acid.
Figure 1
The independent ionic components in compound (I), showing the atom-
labelling scheme and the hydrogen bonds (dashed lines) within the
selected asymmetric unit. Displacement ellipsoids are drawn at the 30%
probability level and H atoms are shown as small spheres of arbitrary
radii.
In the cation of (I), the exocyclic chain adopts an almost
planar extended-chain conformation, with the aryl ring almost
orthogonal to this plane, as shown by the torsion angles
(Table 1). The dihedral angle between the planes of atoms
Acta Cryst. (2007). C63, o585±o587
DOI: 10.1107/S0108270107040450
# 2007 International Union of Crystallography o585

organic compounds
located in off-centre sites of 0.5 occupancy in each of the
anions, which both lie across mirror planes (Madsen & Larsen,
1998).
The unique H atom could not be located in the dicyclo-
hexylammonium salt, and it was ®xed at the mid-point of the
two close O atoms (Ng et al., 1991); this seems a reasonable
assignment in view of the CÐO distances in this compound. In
HÁ Á ÁO hydrogen bond (Table 2). Methylene atom C17 at (x, y,
z) acts as hydrogen-bond donor to carboxyl atom O21A at (x,
1
y, 1 + z), so forming a C32(7) chain running parallel to the
2
2
[001] direction and generated by the c-glide plane at y = 14. The
combination of the [100] and [001] chains generates a sheet of
S(7) and R67(23) rings parallel to (100) (Fig. 3). Two sheets of
this type, related to one another by inversion, pass through
each unit cell, but there are no direction-speci®c interactions
between adjacent sheets.
Ï
tetramethylammonium hydrogen maleate (Drobez et al.,
1985), the OÐH distances were found to be 1.09 (4) and
ꢀ
Ê
1.32 (4) A, with an OÐHÁ Á ÁO angle of 174 (3) and an OÁ Á ÁO
The formation of the chain of NÐHÁ Á ÁO hydrogen bonds in
compound (I) utilizes two O atoms from a single carboxylate
group. This may be contrasted with the chains formed by NÐ
HÁ Á ÁO hydrogen bonds in the hydrogen maleate salts of other
simple aliphatic diamines. In the dimethylammonium (Madsen
& Larsen, 1998) and dicyclohexylammonium (Ng et al., 1991)
salts, the two O atoms utilized in the chain formation form
parts of different carboxyl groups, so that these chains are
both of the C22(9) type, as opposed to C22(6) in compound (I).
By contrast, in the 1:2 hydrogen maleate salts derived from
4,40-bipyridyl and 1,2-di-4-pyridylethane, the NÐHÁ Á ÁO
hydrogen bonds generate three-component aggregates, viz.
anion±cation±anion, which lie across twofold rotation axes
and inversion centres, respectively. The incorporation of these
aggregates into supramolecular structures of higher dimen-
sionality, twofold interwoven frameworks in the case of the
4,40-bipyridyl salt and a sheet in the case of 1,2-di-4-pyridyl-
ethane, depends solely on multiple CÐHÁ Á ÁO hydrogen bonds
(Bowes et al., 2003).
Ê
distance of 2.403 (4) A; although the precision of the OÐH
distances does not permit a ®rm distinction between a centred
and a close-bound H atom, the associated CÐO distances
support the centred model.
The location of the H atom closely bonded to just one of the
O atoms found here for compound (I) is consistent with the
locations of this atom found in a number of hydrogen maleate
salts of heteroaromatic diamines (Bowes et al., 2003). Despite
the presence of the short OÐHÁ Á ÁO hydrogen bond in
compound (I), the anion is not completely planar and the CÐ
CÐC angles at C22 and C23 are both ca 130ꢀ.
The ionic components in (I) are linked into chains by two
strong NÐHÁ Á ÁO hydrogen bonds (Table 2). Atom N17 in the
cation at (x, y, z) acts as hydrogen-bond donor to atom O24A
in the anion also at (x, y, z), and to atom O24B in the anion at
(x, 1 + y, z), so generating by translation a C22(6) chain
(Bernstein et al., 1995) running parallel to the [010] direction
(Fig. 2). These chains are further weakly linked by a single CÐ
Figure 2
Part of the crystal structure of compound (I), showing the formation of a
hydrogen-bonded C22(6) chain parallel to [010]. For the sake of clarity, H
atoms bonded to C atoms which play no role in the supramolecular
aggregation have been omitted. Atoms marked with an asterisk (*) or a
hash symbol (#) are at the symmetry positions (x, 1 + y, z) and (x, 1 + y,
z), respectively.
Figure 3
Part of the crystal structure of compound (I), showing the formation of a
hydrogen-bonded sheet parallel to (100). For the sake of clarity, H atoms
bonded to C atoms which play no role in the supramolecular aggregation
have been omitted.
C8H12N+ÁC4H3O4
Acta Cryst. (2007). C63, o585±o587
ꢁ
o586 Santacruz et al.

organic compounds
treated as riding atoms in geometrically idealized positions, with
Ê
distances CÐH = 0.95 (aromatic and alkenic), 0.98 (CH3) or 0.99 A
Experimental
A mixture of maleic anhydride (0.826 mmol) and benzylmethylamine
(0.833 mmol) was dissolved in undistilled ethyl acetate (2 ml) and
stirred at room temperature for 1 h. The resulting white solid,
compound (I), was collected by ®ltration and washed with cold ethyl
acetate (yield 10%, m.p. 384 K). IR (KBr, ꢁ, cm 1): 3499, 3359, 2932,
2835, 2785, 2698, 1666, 1583, 1489, 1367, 754, 700; MS (70 eV): m/e
Ê
Ê
(CH2), NÐH = 0.92 A and OÐH = 0.84 A, and with Uiso(H) =
kUeq(carrier), where k = 1.5 for the hydroxyl and methyl groups and
1.2 for all other H atoms.
Data collection: COLLECT (Nonius, 1999); cell re®nement:
DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD
(Duisenberg et al., 2003); program(s) used to solve structure: SIR2004
(Burla et al., 2005); program(s) used to re®ne structure: OSCAIL
(McArdle, 2003) and SHELXL97 (Sheldrick, 1997); molecular
graphics: PLATON (Spek, 2003); software used to prepare material
for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).
(%) 236 (0.6, M
1), 192 (17), 120 (54), 91 (100). Crystals of (I)
suitable for single-crystal X-ray diffraction were grown by slow
evaporation of a solution in ethyl acetate. The identical product was
obtained in quantitative yield by stirring an equimolar mixture of
maleic acid and benzylmethylamine in ethyl acetate at ambient
temperature.
Â
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The authors thank the Servicios Tecnicos de Investigacion
Â
of the Universidad de Jaen and the staff for the data collec-
Crystal data
C8H12N+ÁC4H3O4
3
Ê
V = 1194.13 (15) A
Z = 4
Mr = 237.25
Monoclinic, P21=c
Â
tion. JC thanks the Consejerõa de Innovacion, Ciencia y
Empresa (Junta de Andalucõa, Spain) and the Universidad de
Jaen for ®nancial support. RA and LS thank COLCIENCIAS
and UNIVALLE (Universidad del Valle, Colombia) for
®nancial support. RA also thanks AUIP for supporting a
Â
research trip to Universidad de Jaen.
Â
Mo- Kꢀ radiation
Â
1
Ê
a = 13.1084 (10) A
Ê
b = 5.6177 (2) A
c = 17.6911 (13) A
ꢂ = 113.566 (7)ꢀ
ꢃ = 0.10 mm
T = 120 (2) K
Â
Ê
0.40 Â 0.31 Â 0.15 mm
Data collection
Bruker Nonius KappaCCD area-
detector diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.969, Tmax = 0.985
28597 measured re¯ections
2748 independent re¯ections
1768 re¯ections with I > 2ꢄ(I)
Rint = 0.055
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GZ3098). Services for accessing these data are
described at the back of the journal.
Re®nement
R[F2 > 2ꢄ(F2)] = 0.047
wR(F2) = 0.133
S = 1.07
156 parameters
H-atom parameters constrained
References
3
Ê
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Áꢅmax = 0.23 e A
3
Ê
0.32 e A
2748 re¯ections
Áꢅmin
=
Table 1
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ꢀ
Ê
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Ï
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C22ÐC23ÐC24
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O21AÐC21ÐC22ÐC23 8.2 (3)
O21BÐC21ÐC22ÐC23 172.5 (2)
C12ÐC11ÐC17ÐN17
O24AÐC24ÐC23ÐC22 17.2 (3)
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ꢀ
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Â
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DÐHÁ Á ÁA
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N17ÐH17CÁ Á ÁO24A
N17ÐH17DÁ Á ÁO24Bi
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0.84
0.92
0.92
0.99
1.63
1.99
1.90
2.52
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2.882 (2)
2.802 (2)
3.474 (2)
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È
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1
2
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The P21/c space group was uniquely assigned from the systematic
absences. All H atoms were located in difference maps and then
C8H12N+ÁC4H3O4
o587
ꢁ
Acta Cryst. (2007). C63, o585±o587
Santacruz et al.