organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
example, the N1ÐH1 group is considered a bifurcated donor
because it interacts with atoms N2 and O3. Atom O2 is
considered as a trifurcated acceptor because it interacts with
the C6ÐH6, C4ÐH4 and C7ÐH7 bonds. All such interactions
are important because they contribute to the geometry of the
lattice. The HSO4 ions are joined together by strong OÐ
HÁ Á ÁO S hydrogen bonds that are nearly ideal in geometry
(Steiner, 1998, 2002; Jeffrey, 1997).
As a result of these interactions, the 1,3-dihydrobenzo-
triazolium cations pack in a herring-bone pattern in the ab
plane with the hydrogensulfate anions interspersed (Fig. 3). A
polymorphic structure of (II) was reported by Giordano
(1980), which crystallizes in the orthorhombic space group
Pbcn. The phosphoric acid salt of 1,3-dihydrobenzotriazole,
(IV), is also known (Emsley et al., 1988) and crystallizes in the
triclinic space group P1 with similar packing to (II).
ISSN 0108-2701
A new sulfate acid polymorph of
1,3-dihydrobenzotriazole
Angel Ramos-Organilloa* and Rosalinda Contrerasb
a
Â
Facultad de Ciencias Quõmicas, Universidad de Colima, km 9 carretera Colima-
Coquimatlan, Coquimatlan, Colima, CP 28400, Mexico, and bDepartamento de
Â
Â
Â
Â
Â
Quõmica, Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico
Â
Nacional, Apartado Postal 14-740, 07000 Mexico, DF, Mexico
Correspondence e-mail: aaramos@ucol.mx
In Table 2, the bond distances for polymorphs (II) and (III)
(Giordano, 1980) and compound (IV) (Emsley et al., 1988) are
compared. Polymorphs (II) and (III) show similar bond
distances, while in (IV) they are slightly longer. It can also be
Received 30 April 2007
Accepted 26 June 2007
Online 9 August 2007
A new sulfate acid polymorph of 1,3-dihydrobenzotriazole,
+
viz. 1,3-dihydrobenzotriazolium hydrogensulfate, C6H6N3 Á-
HSO4 , differs from an existing polymorph in that the
polymeric interaction between the HSO4 anions, together
with different classical (DÐHÁ Á ÁA) and nonclassical (CÐ
HÁ Á ÁA) interactions, changes the space group.
Comment
Heterocyclic compound (I) (see scheme) contains acidic H
atoms and N atoms with lone electron pairs. The presence of
both acidic and basic characteristics gives the molecule the
ability to participate in a wide variety of interactions. More-
over, tautomerism in (I) can change the reactivity depending
on the starting material (Jagerovic et al., 2002; Katritzky et al.,
1998; Gallinek, 1897; Elder®el, 1957). This diversity gives rise
to the possibility of different structural arrangements or
polymorphs. For aliphatic amines this outcome is expected,
but in this case the molecule is planar and polymorphs are not
common (Blagden & Davey, 2003; Davey, 2003; Mak & Zhou,
1992; Dunitz, 1979).
Figure 1
A view of the molecule of (II), showing 50% probability displacement
ellipsoids and the atom-numbering scheme.
The title compound, (II), crystallized in the monoclinic
space group P21/c from a mixture of tetrahydrofuran (THF)
and hexane. The structure (Fig. 1) shows the presence of acidic
H atoms on atom N3 and on the HSO4 counter-ion. The
crystal packing (Fig. 2) is structured by classical and
nonclassical hydrogen bonds, the most important of which are
listed in Table 1. Three of these are classical hydrogen bonds
(NÐHÁ Á ÁO), while the others are nonclassical (CÐHÁ Á ÁO).
Two particularly strong interactions are H3Á Á ÁO4 and
H1Á Á ÁO3. Some of the hydrogen bonds are complex. For
Figure 2
The polymeric arrangements in (II), formed by classical and nonclassical
hydrogen bonds (dotted lines). The view is along the b axis. [Symmetry
codes: (i) x, y + 32, z 21; (ii) x, y
1
2
,
z + 12; (iii) x + 1, y + 21, z + 12.]
Acta Cryst. (2007). C63, o501±o503
DOI: 10.1107/S0108270107031241
# 2007 International Union of Crystallography o501
Ramos-Organillo, Angel
