4-[(Z)-2-(Methyl-sulfan-yl)ethen-yl]-1-phenyl-1H-1,2,3-triazole: An order-disorder (OD) inter-pretation of twinning

Article abstract of DOI:10.1107/S0108270111043083

The title compound, C₁₁H₁₁SN₃, crystallizes as twins with a twin volume fraction of 0.4232 (13). An order-disorder (OD) inter-pretation gives a plausible explanation of the crystallization behaviour. The structure is a pol

Full text of DOI:10.1107/S0108270111043083

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
scattering, noncrystallographic extinctions and twinning, and
as a means of classifying structures by symmetry principles.
For example, all dense sphere packings can be considered to
belong to the same OD family. OD theory has been success-
fully applied to all major classes of compounds. In the field of
minerals and inorganic synthetic compounds, it has been very
helpful in solving structural problems by suggesting reliable
structural arrangements (Ferraris et al., 2004). It has also been
applied, though less frequently, to organic salts and molecular
compounds [e.g. urotropin azelate (Bonin et al., 2003), tris-
(bicyclo[2.1.1]hexeno)benzene (Birkedal et al., 2003; Ferraris
et al., 2004) and nonactin (Dornberger-Schiff, 1966)], and
recently even to proteins (Pletnev et al., 2009).
ISSN 0108-2701
4-[(Z)-2-(Methylsulfanyl)ethenyl]-
1-phenyl-1H-1,2,3-triazole: an
order–disorder (OD) interpretation
of twinning
Berthold Stoger,a* Daniel Lumpib and Johannes Frohlichb
¨
¨
Since OD theory is based on geometric relations, it is not
uncommon that OD layers do not correspond to layers in the
crystallochemical sense. In this work, layers according to OD
description will be designated by a letter A, according to the
layer notation of Grell & Dornberger-Schiff (1982), whereas
layers derived from crystallochemical considerations are
denoted B.
During our systematic studies of a novel class of organic
materials exhibiting nonlinear optical properties (Lumpi et al.,
2011), we obtained crystals of the title compound, (I).
Although they do not fulfill the basic requirements for second
harmonic generation, since they crystallize in the centrosym-
metric space group P21/c, they are interesting from a crystal-
lographic point of view because they are systematically
twinned and can be described as OD twins.
aInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry,
Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria,
and bInstitute of Applied Synthetic Chemistry, Division of Organic Chemistry, Vienna
University of Technology, Getreidemarkt 9/163, A-1060 Vienna, Austria
Correspondence e-mail: bstoeger@mail.zserv.tuwien.ac.at
Received 4 October 2011
Accepted 17 October 2011
Online 31 October 2011
The title compound, C11H11SN3, crystallizes as twins with a
twin volume fraction of 0.4232 (13). An order–disorder (OD)
interpretation gives a plausible explanation of the crystal-
lization behaviour. The structure is a polytype with a
maximum degree of order (MDO). The contact plane is
interpreted as being composed of a fragment of the second
MDO polytype. The planes of the triazole and phenyl rings are
twisted by 36.88 (6)ꢀ. Molecules are connected via C—Hꢁ ꢁ ꢁN
hydrogen bonds, forming layers parallel to (100). The layers
can be arranged in geometrically different but energetically
virtually equivalent ways, giving rise to polytypism.
Comment
The order–disorder (OD) theory was conceived in the 1950s
(Dornberger-Schiff, 1956) to explain unusual X-ray diffraction
effects in minerals like wollastonite (Jeffery, 1953) and in
isostructural inorganic compounds such as Maddrell’s salts
and sodium polyarsenates (Dornberger-Schiff et al., 1955). It is
based on the geometric equivalence of pairs of layers, which
also implies energetic equivalence. Structures in which
equivalent sides of a layer can connect to another layer only in
a way where all resulting layer pairs are equivalent fulfil the
vicinity condition (Dornberger-Schiff & Grell-Niemann,
1961). A fundamental result of OD theory states that struc-
tures fulfilling the vicinity condition need not be equivalent or
even ordered. If the vicinity condition gives rise to different
stacking possibilities, one speaks of proper OD structures.
These stacking possibilities are said to belong to the same OD
family. Neglecting interactions between atoms separated by
more than one layer width, all polytypes of an OD family are
energetically equivalent.
In crystals of (I), one crystallographically unique molecule
(Fig. 1) is located on a general position. All interatomic
distances are within the ranges of expected values (Allen et al.,
2006). The phenyl and triazole rings are planar [maximum
Figure 1
The molecular structure of (I), showing the atom-numbering scheme.
C, N and S atoms are represented by dark-, medium- and light-grey
ellipsoids, respectively, drawn at the 75% probability level.
Since its inception, OD theory has been developed into a
versatile theory for the explanation of polytypism, diffuse
o464 # 2011 International Union of Crystallography
doi:10.1107/S0108270111043083
Acta Cryst. (2011). C67, o464–o468

organic compounds
distances from the respective least-squares plane
=
˚
˚
0.0045 (10) A for atom C3 and 0.0042 (9) A for atom C7].
They are twisted about the N1—C1 bond by 36.88 (6)ꢀ. This
twist is explained by repulsive steric forces between the 5- and
ortho-H atoms of the triazole and phenyl rings. In comparable
4-alkyl-1-phenyl-1H-1,2,3-triazoles, not ortho-substituted on
the phenyl ring, the twist is generally less pronounced, with
angles < 30ꢀ. For example, in the closely related propenyl
analogue (Lumpi et al., 2011), the twist angle is 8.87 (5)ꢀ. An
exception is 2,6-bis[1-(4-dimethylaminophenyl)-1H-1,2,3-tri-
azol-4-yl]-4-(3,6,9-trioxadeca-1-yloxycarbonyl)pyridine (Meu-
dtner et al., 2007), exhibiting an exceptionally large twist angle
of 42.7 (2)ꢀ. Interestingly, the second 4-phenyl-1H-1,2,3-tria-
zole moiety of the same molecule is close to being planar [twist
angle = 0.72 (18)ꢀ]. There are a number of such nearly planar
4-phenyl-1,2,3-triazoles, e.g. 4-difluoromethyl-1-(4-methyl-
phenyl)-1H-1,2,3-triazole (Costa et al., 2006), with a twist
angle of 0.34 (14)ꢀ. Moreover, in 1-(4-methoxyphenyl)-4-(tri-
fluoromethyl)triazole (Stepanova et al., 1989), the molecule is
located on a mirror plane, thus resulting in planarity. A similar
phenomenon has been observed and intensely investigated in
the room-temperature phase of biphenyl (Trotter, 1961); the
biphenyl molecule is located on a centre of inversion and is
therefore planar. The preference for a flat geometry, despite
the steric repulsive interaction of the ortho-H atoms, was
explained by a ꢀ–ꢀ interaction between the connected
aromatic rings and by intermolecular interactions (Cailleau et
al., 1979).
Figure 2
The major polytype (P21/c) of (I), viewed down [010]. Atom shading is as
in Fig. 1 and ellipsoids are drawn at the 60% probability level. H atoms,
with the exception of those involved in hydrogen bonds, have been
omitted for clarity. Hydrogen bonds are indicated by dashed lines. Layers
according to the OD interpretation (A1 and A2) are separated by dashed
lines. Layer names of OD and crystallochemical layers are indicated to
the right and left, respectively. Symmetry elements of the whole polytype
are indicated by symbols according to International Tables for Crystal-
lography (Hahn, 2006).
The –CH CH—S– group in (I) is nearly coplanar with the
triazole ring [dihedral angle between the least-squares planes =
5.14 (13)ꢀ], whereas the S-methyl group is located distinctly
off the molecular plane [torsion angle = 168.40 (15)ꢀ]. Only a
few crystal structures of compounds with a similar methyl-
sulfanylvinyl side chain are known. For all of them, similar
torsion angles are observed, viz. 171.2 (3)ꢀ in 2-(2-methyl-
sulfonylprop-1-enyl)-4-methylsulfonylthiophene (Mereiter et
al., 2000) and 159.57 (14)ꢀ in5-methylsulfanyl-3-(morpholin-4-
yl)hexa-2,4-dienenitrile (Mereiter et al., 2001).
decomposed into two kinds of nonpolar (with respect to the
stacking direction [100]) layers, viz. A1 (phenyl rings, without
H2) and A2 (H2, triazole ring and aliphatic chain), which
possess P(b)cm and P(1)21/c1 symmetry, respectively (Fig. 2).
The origins of two adjacent layers are related by a trans-
lation along 1/2a0 ꢂ sc, where a0 is the vector normal to the
layer planes connecting two equivalent layers, and s = ꢃ0.02
(determined from the lattice parameters of the twin compo-
nents. Thus, the OD family of the crystal structure of (I)
belongs to category IV, characterized by the presence of two
kinds of nonpolar OD layers. The OD groupoid family symbol
according to the notation of Grell & Dornberger-Schiff (1982)
reads as
The molecules of (I) are connected via nonclassical
hydrogen bonds (Table 1). The phenyl rings are connected via
C2—H2ꢁ ꢁ ꢁN3 hydrogen bonds to the triazole rings, forming
extended chains running along [001]. These chains are, in turn,
connected by C11—H113ꢁ ꢁ ꢁN2 hydrogen bonds, forming
crystallochemical B layers with symmetry P(1)21/c1 (Fig. 2).
Adjacent B layers connect only via van der Waals interactions
between the phenyl rings. The shortest interlayer C—H
contacts [C4—H4ꢁ ꢁ ꢁC1 and C5—H5ꢁ ꢁ ꢁC2, with Hꢁ ꢁ ꢁC
˚
distances of 2.93 (2) and 3.01 (2) A, respectively] are too long
A1
A2
for C—Hꢁ ꢁ ꢁꢀ interactions. Given a B layer, an adjacent layer
can appear in two orientations, related by mirroring at (001).
These two possibilities result in virtually identical inter- and
intramolecular interactions, which explains the observed
twinning and can be described by purely geometric consid-
erations according to OD theory, as follows.
In order to achieve an OD description, the structure is
‘sliced’ into OD layers with higher symmetry than required by
the space-group symmetry. Accordingly, the structure of (I) is
:
PðbÞcm
Pð1Þ21=c1
½0; sꢄ
The number of stacking possibilities is formally derived
using the NFZ relationship (Durovic, 1997). It is based on
those layer symmetry operations which leave intact the
orientation with respect to the stacking direction. For A1
layers, these form the group P(2)cm. Since the mirror plane
does not apply to A2 layers, given the position of the former,
ˇ
ˇ
ꢅ
Acta Cryst. (2011). C67, o464–o468
Stoger et al. C11H11N3S o465
¨

organic compounds
different orientations related by the mirror operation of A1
layers. Polytype MDO2 is only evidenced indirectly by the
twinning operation. At the contact plane, at least one
A2+A1A2ꢃ triple layer of MDO2 exists.
In all polytypes, the configuration and conformation of the
molecules is identical and intermolecular interaction is
confined to A2 layers. The polytypes only differ in the relative
orientation of molecules which are loosely connected by the
phenyl rings. However, independent of the orientation, the
arrangement of the phenyl rings is virtually identical, due to
the higher symmetry of A1 layers. Thus, the OD interpretation
is valid and gives a plausible explanation of the observed
twinning.
Experimental
¨
The syntheses of (3-bromo-2-thienyl)trimethylsilane (Frohlich &
Kalt, 1990) and azidobenzene (Cwiklicki & Rehse, 2004) were
performed according to previously reported methods. All other
chemicals were obtained commercially and were used without further
purification.
The precursor (Z)-trimethyl[4-(methylsulfanyl)but-3-en-1-yn-1-yl]-
silane, (II), was prepared by analogy with the pentene compound
(Lumpi et al., 2011). To a solution of (3-bromo-2-thienyl)trimethyl-
silane (1.88 g, 8.0 mmol) in dry Et2O (30 ml, 0.3 M) under an argon
atmosphere at 203 K, n-BuLi (3.5 ml, 8.8 mmol; 2.5 M solution in
hexanes) was added over a period of 15 min and the mixture stirred
for 1 h. The mixture was then warmed to 283 K, stirred for 1 h, cooled
to 273 K and MeI (2.50 g, 17.6 mmol) was added. After 1 h at room
temperature, the mixture was poured onto a half-saturated NH4Cl
solution and extracted with Et2O. The organic layer was washed with
brine, dried over anhydrous Na2SO4 and concentrated. Column
chromatography [light petroleum, dichloromethane (1!4%)]
yielded 0.685 g (50%) of (II) as a pale-yellow liquid. 1H NMR
(200 MHz, CDCl3): ꢁ 6.49 (d, J = 10.0 Hz, 1H), 5.49 (d, J = 10.0 Hz,
1H), 2.38 (s, 3H), 0.20 (s, 9H); 13C NMR (50 MHz, CDCl3): ꢁ 143.1
(d), 104.5 (d), 102.9 (s), 101.2 (s), 16.8 (q), ꢃ0.1 (q). Analysis calcu-
lated for C8H14SSi: m/z 171.0658 [M + H]+; found: MS (APCI): m/z
171.0686 [M + H]+.
Figure 3
Global and local symmetry of the (a) MDO1 (P21/c) and (b) MDO2
(Pbcm) polytypes of (I), represented schematically by two non-
equivalent triangles which are black on one side and white on the other.
A small triangle of opposite shading indicates translation along 12 b.
Symmetry elements are as in Fig. 2.
the latter can appear in two orientations related by the mirror
operation, which will be denoted A2+ and A2ꢃ. The twofold
rotation generates the same pair of orientations and the
c-glide applies to A2 layers as well and therefore does not
produce additional possible orientations. For A2 layers, on the
other hand, the operations to be considered are the members
of P(1)c1. All of them apply to adjacent A1 layers. Thus, given
the position of the former, the position of the latter is fixed.
These stacking possibilities give rise to two polytypes with a
maximum degree of order (MDO) (Dornberger-Schiff &
Grell, 1982). For MDO1: P21/c, a = a0 + 2sc and all A2 layers
appear in the same orientation. For MDO2: Pbca, a = 2a0, and
The title compound was prepared by analogy with the propenyl
compound (Lumpi et al., 2011). To a suspension of (II) (0.427 g,
2.51 mmol, 1.00 equivalent), azidobenzene (0.372 g, 3.12 mmol,
1.25 equivalents), CuSO4ꢁ5H2O (0.125 g, 0.50 mmol, 20 mol%) and
sodium ascorbate (0.200 g, 1.01 mmol, 40 mol%) in t-BuOH–H2O
(1:1 v/v, 6.3 ml, 0.4 M) was added potassium fluoride (0.169 g,
2.91 mmol, 1.16 equivalents). The reaction vessel was sealed and
heated at 323 K for 18 h. The reaction mixture was then diluted with
water and extracted with Et2O. The combined organic layers were
washed with brine and dried over anhydrous Na2SO4. Suction
filtration and evaporation of the solvent, followed by column chro-
matography (light petroleum, Et2O, 3:1 v/v) and crystallization from
n-hexane, afforded (I) (0.386 g, 71%) as a white solid. Single crystals
were obtained by recrystallization from n-hexane (m.p. 362.9–
A2 layers appear alternately as A2+ and A2ꢃ
A common feature in OD structures is desymmetrization of
.
1
ˇ
ˇ
layers (Durovic, 1979). Indeed, the symmetry of A layers is
reduced from P(b)cm to P(1)21/c1 and P(b)c21 in MDO1 and
MDO2, respectively. The symmetry of A2 layers, on the other
hand, is retained in both MDO polytypes. The local and global
symmetries of both MDO polytypes are shown schematically
in Fig. 3.
1
362.2 K). H NMR (400 MHz, CD2Cl2): ꢁ 8.21 (s, 1H), 7.77 (d, J =
8.0 Hz, 2H), 7.55 (t, J = 7.8 Hz, 2H), 7.46 (t, J = 7.4 Hz, 1H), 6.65 (d, J =
10.8 Hz, 1H), 6.43 (d, J = 10.6 Hz, 1H), 2.48 (s, 3H); 13C NMR
(100 MHz, CD2Cl2): ꢁ 145.8 (s), 137.6 (s), 131.3 (d), 130.3 (d), 129.1
(d), 121.0 (d), 120.4 (d), 114.5 (d), 18.6 (q). Analysis calculated for
C11H11N3S: m/z 218.0746 [M + H]+; found: MS (ESI): m/z 218.0756
[M + H]+.
As mentioned previously, crystals of (I) are twins. The twin
components are of the MDO1 polytype, appearing in two
ꢅ
o466 Stoger et al. C11H11N3S
Acta Cryst. (2011). C67, o464–o468
¨

organic compounds
Table 1
Hydrogen-bond geometry (A, ).
ꢀ
˚
D—Hꢁ ꢁ ꢁA
D—H
Hꢁ ꢁ ꢁA
Dꢁ ꢁ ꢁA
D—Hꢁ ꢁ ꢁA
C11—H113ꢁ ꢁ ꢁN2i
0.94 (2)
0.98 (2)
2.62 (3)
2.41 (2)
3.503 (2)
3.3220 (19)
156 (2)
154.6 (17)
C2—H2ꢁ ꢁ ꢁN3ii
1
2
1
2
Symmetry codes: (i) ꢃx þ 2; ꢃy; ꢃz; (ii) x; ꢃy þ ; z þ .
Crystal data
3
˚
C11H11N3S
Mr = 217.29
V = 1065.64 (5) A
Z = 4
Monoclinic, P21=c
Mo Kꢃ radiation
ꢄ = 0.27 mmꢃ1
T = 100 K
0.45 ꢆ 0.38 ꢆ 0.22 mm
˚
a = 12.6198 (3) A
˚
b = 7.8465 (2) A
˚
c = 10.7699 (3) A
ꢂ = 92.2261 (17)ꢀ
Data collection
Bruker APEXII CCD area-detector
diffractometer
Absorption correction: multi-scan
(TWINABS; Bruker, 2008)
Tmin = 0.888, Tmax = 0.943
23874 measured reflections
4678 independent reflections
3654 reflections with I > 2ꢅ(I)
Rint = 0.045
Figure 4
The (h1l) plane of the diffraction pattern of (I), reconstructed from CCD
data. Only the h ꢇ 0, l ꢇ 0 quadrant is shown for clarity. Fully overlapping
reflections (l = 11) are indicated by a rectangle.
Refinement
R[F2 > 2ꢅ(F2)] = 0.048
wR(F2) = 0.111
S = 1.03
181 parameters
All H-atom parameters refined
ꢃ3
˚
Áꢆmax = 0.46 e A
ꢃ3
˚
4678 reflections
Áꢆmin = ꢃ0.30 e A
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GZ3202). Services for accessing these data are
described at the back of the journal.
Of five crystals analysed, all were twinned. The reflections of the
two twin components were separated using the RLATT software
(Bruker, 2008). In all cases, the twin domains were related by
mirroring at (001). The final unit-cell parameters were refined during
data reduction with SAINT-Plus (Bruker, 2008). The parameters of
both twin domains were restrained to the same values.
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