Synthesis and structures of substituted triphen-yl(phenyl-imino)phospho- ranes

Article abstract of DOI:10.1107/S0108270109047763

Three substituted triphen-yl(phenyl-imino)phospho-ranes, namely (4-cyano-phenyl-imino)triphenyl-phospho-rane, C₂₅H₁₉N ₂P, (I), (4-nitro-phenyl-imino)triphenyl-phospho-rane, C ₂₄H₁₉N₂O₂P, (II), and (3-nitro-phenyl-imino)triphenyl-phospho-rane, C₂₄H₁₉N ₂O₂P, (III), were synthesized as precursors for the preparation of substituted diphenyl-carbodiimides. All three compounds display a supramolecular arrangement in which the substituted benzene rings are organized in an antiparallel fashion. The nitro group on the ring participates in C - H...O and O...π inter-actions, forming inter-molecular dimers. Compound (III) shows disorder which involves the rotation of one of the phenyl rings of the triphenyl-phosphine group.

Full text of DOI:10.1107/S0108270109047763

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
and the influence of substituents on the properties of the
carbon backbone have been investigated (Baeke et al., 2007;
Vande Velde et al., 2004; Vande Velde, Baeke et al. 2005;
Vande Velde, De Borger et al., 2005; Vande Velde, Geise et al.,
2005; Vande Velde et al., 2006; Irngartinger et al., 1994;
Hakansson et al., 1992; Bartholomew et al., 2000a,b; Coates et
al., 1998; Nohra et al., 2006; Renak et al., 1999; Sancho-Garcia
et al., 2005; Zeller et al., 2005). However, keeping in mind the
tunability of these materials, it is equally interesting to
determine the effects of the replacement of the ethenylic
—CH CH— link by other spacers such as —CH N—
ISSN 0108-2701
Synthesis and structures of substituted
triphenyl(phenylimino)phosphoranes
Roeland De Borger,a Alain Collas,a Roger Dommisseb and
Frank Blockhuysa*
(benzylideneanilines), —N
C
S
—N N— (carbodiimides) fragments.
N— (sulfodiimides) or
aUniversity of Antwerp, Department of Chemistry, Universiteitsplein 1, 2610 Wilrijk,
Belgium, and bUniversity of Antwerp, Department of Chemistry, Groenenborgerlaan
171, 2020 Antwerpen, Belgium
Correspondence e-mail: frank.blockhuys@ua.ac.be
Received 19 March 2009
Accepted 11 November 2009
Online 19 December 2009
Three substituted triphenyl(phenylimino)phosphoranes,
namely (4-cyanophenylimino)triphenylphosphorane, C25H19-
N2P, (I), (4-nitrophenylimino)triphenylphosphorane, C24H19-
N2O2P, (II), and (3-nitrophenylimino)triphenylphosphorane,
C24H19N2O2P, (III), were synthesized as precursors for the
preparation of substituted diphenylcarbodiimides. All three
compounds display a supramolecular arrangement in which
the substituted benzene rings are organized in an antiparallel
fashion. The nitro group on the ring participates in C—HÁ Á ÁO
and OÁ Á Áꢀ interactions, forming intermolecular dimers.
Compound (III) shows disorder which involves the rotation
of one of the phenyl rings of the triphenylphosphine group.
The work we present here deals with the precursors to
carbodiimide derivatives of distyrylbenzenes, i.e. triphenyl-
(phenylimino)phosphoranes. Because of the recent interest in
carbodiimides as precursors for nitrogen-containing hetero-
cycles, the synthesis of these compounds has received
considerable attention (Ding et al., 2000, 2004; Liu et al., 2006;
Okawa et al., 1996; Yuan et al., 2006; Zhao et al., 2006;
Wamhoff et al., 1993; Eguchi, 2005). The most important
pathway to obtain carbodiimides is through the aza-Wittig
reaction of iminophosphoranes with isocyanates (Ding et al.,
2004, 2005; Liu et al., 2006; Zhao et al., 2006), since this
reaction proceeds under mild conditions, requires only readily
available precursors and does not involve the use of difficult-
to-handle compounds such as phosgene (Kurzer & Douraghi,
1967; Mikolajczyk & Kielbasinski, 1981; Ulrich & Sayigh,
1966). The required iminophosphoranes can be obtained by a
Staudinger reaction from azide derivatives (Ding et al., 2000;
Okawa et al., 1996; Kurzer & Douraghi, 1967) or, more
conveniently, by the direct reaction of an aromatic amine with
triphenylphosphine (Ding et al., 2004, 2005; Liu et al., 2006;
Okawa et al., 1996; Yuan et al., 2006; Zhao et al., 2006), as
depicted in the scheme above. In this work, we report the
molecular and crystal structures of the three precursor
iminophosphoranes (I), (II), and (III), which were obtained
using the latter reaction.
Comment
There is considerable current interest in organic semi-
conductors mainly because of the convenient and easy way in
which their molecular structures, and hence their properties,
can be tuned to a specific application. This is in stark contrast
to the present-day CMOS (complementary metal oxide
semiconductor) technology where such tuning is almost
impossible. Switching from polymeric to oligomeric organic
materials is a worthwhile undertaking because of the
numerous opto-electronic applications for which these new
¨
compounds are used, as has been discussed in depth by Mullen
& Wegner (1998) and Segura & Martin (2000). The most
important reason for making this transition is the fact that it is
far easier to produce, purify and structurally characterize
oligomers than polymers, as they are monodisperse materials.
For these reasons, oligomers have been extensively used as
model compounds for polymers but it is far more rewarding to
study the properties of these oligomeric organic semi-
conductor materials for their own sake.
The solid-state structures and electronic properties of one
particular class of these oligomeric organic semiconductors,
viz. distyrylbenzenes, oligomeric derivatives of PPV [poly(p-
phenylene vinylene)], have already been extensively studied
o50 # 2010 International Union of Crystallography
doi:10.1107/S0108270109047763
Acta Cryst. (2010). C66, o50–o54

organic compounds
Figure 2
Packing and the C—HÁ Á Áꢀ contacts of (I).
what larger. The values of the C1—N1—P1—C13 torsion
angle indicate that ring C of the triphenylphosphine group is
only slightly twisted compared to the plane formed by the
P
N bond and ring A, whereas the torsion angles of rings B
and D vary between approximately 40 and 85ꢀ. In comparison
with the two other angles between the P N bond and the
rings of the triphenylphosphine group, the N1—P1—C13
angle is much smaller due to the intramolecular C14—
H14Á Á ÁN1 interaction, of which the HÁ Á ÁN contact distances
ꢀ
ꢀ
˚
˚
and C—HÁ Á ÁN angles are 2.51 A/108 , 2.51 (2) A/110 and
ꢀ
˚
2.67 A/105 for compounds (I), (II) and (III), respectively.
This smaller N1—P1—C13 angle can also be found in the
structures of related triphenyl(phenylimino)phosphoranes
such as the parent triphenyl(phenylimino)phosphorane
[refcode GEHRIU (Bohm et al., 1988) in the Cambridge
Structural Database (CSD; Allen, 2002)], (2-aminophenyl-
imino)triphenylphosphorane (refcode JOZYIG; Llamas-Saiz
et al., 1992), [2-(N,N-dimethylamino)phenylimino]triphenyl-
phosphorane (refcode HATXOP; Llamas-Saiz & Foces-Foces,
1994)
and
(refcode BPITPP; Hewlins, 1971).
(4-bromophenylimino)triphenylphosphorane
The crystal structure of (4-cyanophenylimino)triphenyl-
phosphorane, (I) (Figs. 1 and 2), is composed of alternating
layers of cyanophenyl rings and triphenylphosphine groups.
Within the cyanophenyl layer, the fragments are oriented in an
antiparallel fashion. Successive molecules are linked in the
Figure 1
The molecular structures of (I), (II) and (III), the last showing the
disorder in ring B, C7—C8—C9—C10—C11—C12 being the major
conformer. Displacement ellipsoids are drawn at the 50% probability
level.
b-axis direction in the triphenylphosphine layer by C16—
i
ꢀ
˚
H16Á Á ÁCgB contacts [2.83 A/129 ; symmetry code: (i) 1 À x,
12 + y, 12 À z] (represented by the dotted lines in Fig. 2), in which
CgB is the centroid of ring B. These two layers combine into
two-dimensional layers, which are stacked on top of each
other to give the three-dimensional structure. Successive
stacked layers are connected by C21—H21Á Á ÁCgAii contacts
Table 1 presents selected geometric parameters of the three
triphenyl(phenylimino)phosphoranes under investigation; the
numbering of the atoms can be found in the scheme. The
molecular geometries are similar for the three compounds. As
can be seen from the values of the C6—C1—N1—P1 torsion
angle, ring A is almost coplanar with the N P bond, even
though for the 3-nitro derivative (III) the deviation is some-
ꢀ
˚
[2.72 A/159 ; symmetry code: (ii) 1 + x, y, z] (not shown in
Fig. 2).
The packing of (4-nitrophenylimino)triphenylphosphorane,
(II), shown in Fig. 3(a), is based on dimers with the nitro-
ꢁ
Acta Cryst. (2010). C66, o50–o54
De Borger et al.
C25H19N2P, C24H19N2O2P and C24H19N2O2P o51

organic compounds
Figure 4
(a) Graphical representation of the packing and network of C—HÁ Á ÁO
contacts connecting the dimers of (III) (only the major conformer is
shown), and (b) a view of the C—HÁ Á ÁO and OÁ Á ÁCg contacts generating
the dimers. The molecule on the right is related to that on the left by the
symmetry code (Àx + 1, Ày + 1, Àz + 1).
Figure 3
(a) Graphical representation of the packing and network of C—HÁ Á ÁO
contacts connecting the dimers of (II), and (b) a view of the C—HÁ Á ÁO
contact generating the dimers. The molecule on the left is related to that
on the right by the symmetry code (Àx + 2, Ày + 1, Àz + 1).
compound (II). Two molecules are involved in a dimer via
three separate intermolecular interactions, which are repre-
sented by the dotted lines in Fig. 4(b). The first is the N2—
O2Á Á ÁCgAvi contact [3.798 (4) A/92.77 (17) ; symmetry code:
(vi) 1 À x, 1 À y, 1 À z] which is possible again because of the
lower electron density in ring A due to the presence of the
ꢀ
˚
phenyl rings in an antiparallel cofacial arrangement, one of
which is shown in Fig. 3(b). These dimers are due to inter-
molecular N2—O1Á Á ÁCgAiii [3.473 (2) A/84.81 (11) ; sym-
nitro group. The other two are C—HÁ Á ÁO contacts, i.e. C8—
ꢀ
˚
vi
ꢀ
ꢀ
˚
˚
metry code: (iii) 2 À x, 1 À y, 1 À z] (not shown in Fig. 3b) and
H8Á Á ÁO2vi (2.63 A/122 ) and C9—H9Á Á ÁO2 (2.62 A/123 ).
These dimers are then connected to adjacent molecules by a
C—HÁ Á ÁO interaction involving nitro atom O1, which was
C24—H24Á Á ÁO1iii [2.68 (3) A/145 (2) ] contacts (represented
by the dotted lines in Fig. 3b). The former are possible most
likely because of the fact that ring A is electron-deficient due
to the presence of the electron-withdrawing nitro group. The
dimers are then linked into a three-dimensional structure
ꢀ
˚
unused in the dimer contacts, i.e. C14—H14Á Á ÁO1vii [2.70 A/
˚
128ꢀ; symmetry code: (vii) 1 À x, 2 À y, 1 À z] (represented by
the dotted lines in Fig. 3a). The result is a supramolecular
structure which displays alternating layers of nitrophenyl and
triphenylphosphine groups.
through C22—H22Á Á ÁN1iv contacts [2.67 (2) A/152.3 (6) ;
symmetry code: (iv) 1 + x, 3 À y, 12 + z] (not shown in Fig. 3b)
and a network of C—HÁ2Á ÁO contacts consisting of C9—
ꢀ
˚
The fact that the crystal structures of (II) and (III) are based
on intermolecular dimers sets them apart from (I). These
dimers owe their existence mainly to the presence of the nitro
groups: they generate one [for (II)] or two [for (III)] C—
HÁ Á ÁO interactions and, because of the reduced electron
density in the rings A of (II) and (III), as a consequence of the
electron-withdrawing properties of the nitro group, one
OÁ Á ÁCg interaction. Thus, the nitro group in the 3-position in
(III) generates one more intermolecular contact within the
i
v
ꢀ
˚
H9Á Á ÁO2 [2.59 (3) A/139.0 (16) ] and C10—H10Á Á ÁO1 con-
ꢀ
1
˚
tacts [2.701 (19) A/132.7 (15) ; symmetry code: (v) 2 À x, 2 + y,
1
2
À z] (represented by the dotted lines in Fig. 3a). The latter
generate extended chains in the a-axis direction, in which nitro
groups alternate with rings B of the triphenylphosphine
fragment, which contain H9 and H10.
The packing of (3-nitrophenylimino)triphenylphosphorane,
(III), which is presented in Fig. 4(a), is similar to that of
ꢁ
o52 De Borger et al.
C25H19N2P, C24H19N2O2P and C24H19N2O2P
Acta Cryst. (2010). C66, o50–o54

organic compounds
Data collection
dimer than the nitro group in the 4-position in (II) does. The
supramolecular structure of (III), on the other hand, can count
on just one intermolecular C—HÁ Á ÁO contact, while for (II),
one C—HÁ Á ÁN and two additional C—HÁ Á ÁO interactions
become available from the nitro group in the 4-position. For
(I), the nitrile functionalities are not involved in the supra-
molecular structure and the whole is based on weaker C—
HÁ Á Áꢀ interactions. Since the previously mentioned related
triphenyl(phenylimino)phosphoranes all have electron-
donating substituents, the typical dimers found in compounds
(II) and (III) are absent due to the resulting higher electron
density in ring A. Their packing is mainly based on C—HÁ Á Áꢀ
contacts as in compound (I), although ꢀ–ꢀ interactions can be
found in HATXOP (Llamas-Saiz & Foces-Foces, 1994) and
JOZYIG (Llamas-Saiz et al., 1992), and the structure of
HATXOP displays C—HÁ Á ÁN interactions.
Enraf–Nonius CAD-4
diffractometer
7279 measured reflections
3481 independent reflections
2198 reflections with I > 2ꢄ(I)
Rint = 0.041
3 standard reflections
frequency: 60 min
intensity decay: none
Refinement
R[F2 > 2ꢄ(F2)] = 0.037
wR(F2) = 0.095
S = 1.01
253 parameters
H-atom parameteÀrs3 constrained
˚
Áꢅmax = 0.20 e A
Áꢅmin = À0.23 e A
À3
˚
3481 reflections
Compound (II)
Crystal data
3
˚
V = 2018.7 (9) A
Z = 4
C24H19N2O2P
Mr = 398.38
Monoclinic, P21=c
Mo Kꢂ radiation
ꢃ = 0.16 mmÀ1
T = 293 K
˚
a = 9.118 (2) A
˚
b = 17.536 (4) A
Experimental
˚
c = 14.245 (4) A
0.4 Â 0.2 Â 0.2 mm
ꢁ = 117.591 (17)ꢀ
All reagents and solvents were obtained from ACROS and used as
received. The synthetic pathway for the preparation of compounds
(I), (II) and (III) is shown in the scheme: the appropriately substi-
tuted aniline was stirred at room temperature with the triphenyl-
phosphine/hexachloroethane/triethylamine system in acetonitrile and
the resulting precipitate was recrystallized from ethanol to obtain
large crystals of the desired products. The melting points are uncor-
rected. For (I), triethylamine (18.2 g, 0.18 mol) was added slowly to a
solution of 4-cyanoaniline (7.1 g, 0.06 mol), triphenylphosphine
(23.6 g, 0.09 mol) and hexachloroethane (21.3 g, 0.09 mol) in dry
acetonitrile (200 ml). The mixture was stirred at room temperature
overnight and then cooled in a refrigerator. The precipitated yellow
solid was filtered off and recrystallized from ethanol. The yield was
15.4 g (68%); m.p. 461 K. For (II), triethylamine (18.2 g, 0.18 mol)
was added slowly to a solution of 4-nitroaniline (8.3 g, 0.06 mol),
triphenylphosphine (23.6 g, 0.09 mol) and hexachloroethane (21.3 g,
0.09 mol) in dry acetonitrile (200 ml). The mixture was stirred at
room temperature overnight and then cooled in a refrigerator. The
precipitated yellow solid was filtered off and recrystallized from
ethanol. The yield was 16.4 g (69%); m.p. 428 K. For (III), triethyl-
amine (18.2 g, 0.18 mol) was added slowly to a solution of 3-nitro-
aniline (8.3 g, 0.06 mol), triphenylphosphine (23.6 g, 0.09 mol) and
hexachloroethane (21.3 g, 0.09 mol) in dry acetonitrile (200 ml). The
mixture was stirred at room temperature overnight and then cooled
in a refrigerator. The precipitate was filtered off but proved to be
mostly triethylammonium chloride. The filtrate was partially evapo-
rated, during which an orange precipitate formed. This new precipi-
tate was filtered off and recrystallized from ethanol. The yield was
12.3 g (52%); m.p. 407 K. X-ray quality crystals of compounds (I), (II)
and (III) were grown by slow cooling of hot ethanol solutions and
were cut to the appropriate dimensions using a razor blade.
Data collection
Enraf–Nonius CAD-4
diffractometer
7417 measured reflections
3544 independent reflections
2682 reflections with I > 2ꢄ(I)
Rint = 0.029
3 standard reflections
frequency: 60 min
intensity decay: none
Refinement
R[F2 > 2ꢄ(F2)] = 0.032
wR(F2) = 0.089
S = 1.02
3544 reflections
338 parameters
H atoms treated by a mixture of
independent and constrained
refinement
À3
˚
Áꢅmax = 0.21 e A
À3
˚
Áꢅmin = À0.23 e A
Compound (III)
Crystal data
C24H19N2O2P
Mr = 398.38
Triclinic, P1
ꢆ = 78.410 (3)ꢀ
V = 1018.3 (9) A
Z = 2
3
˚
˚
a = 9.001 (2) A
Mo Kꢂ radiation
ꢃ = 0.16 mmÀ1
T = 293 K
0.4 Â 0.4 Â 0.4 mm
˚
b = 9.770 (7) A
˚
c = 12.098 (5) A
ꢂ = 84.340 (4)ꢀ
ꢁ = 78.190 (4)ꢀ
Data collection
Enraf–Nonius CAD-4
diffractometer
7180 measured reflections
3590 independent reflections
3018 reflections with I > 2ꢄ(I)
Rint = 0.016
3 standard reflections
frequency: 60 min
intensity decay: 1%
Refinement
Compound (I)
R[F2 > 2ꢄ(F2)] = 0.039
wR(F2) = 0.110
S = 1.04
3590 reflections
281 parameters
13 restraints
H-atom parameteÀrs3 constrained
Crystal data
˚
3
˚
Áꢅmax = 0.21 e A
C25H19N2P
Mr = 378.39
V = 1977.1 (9) A
Z = 4
À3
˚
Áꢅmin = À0.24 e A
Monoclinic, P21=c
Mo Kꢂ radiation
ꢃ = 0.15 mmÀ1
T = 293 K
0.4 Â 0.2 Â 0.2 mm
˚
a = 8.581 (3) A
˚
b = 13.8620 (10) A
˚
c = 17.170 (4) A
When possible, H atoms were located in a difference map and left
free to refine, resulting in C—H distances between 0.90 (2) and
ꢁ = 104.53 (2)ꢀ
ꢁ
Acta Cryst. (2010). C66, o50–o54
De Borger et al.
C25H19N2P, C24H19N2O2P and C24H19N2O2P o53

organic compounds
Table 1
Selected geometric parameters (A, ) for (I), (II) and the major disorder
component of (III).
References
ꢀ
˚
Allen, F. H. (2002). Acta Cryst. B58, 380–388.
Baeke, J. K., Nowaczyk, J., Moens, M., Chen, L. J., Dieltiens, P., Geise, H. J.,
Zeller, M., Hunter, A. D. & Blockhuys, F. (2007). J. Electroanal. Chem. 599,
1–11.
(I)
(II)
(III)
Bartholomew, G. P., Bu, X. H. & Bazan, G. C. (2000a). Chem. Mater. 12, 1422–
1430.
Bartholomew, G. P., Bu, X. H. & Bazan, G. C. (2000b). Chem. Mater. 12, 2311–
2318.
Bohm, E., Dehnicke, K., Beck, J., Hiller, W., Strohle, J., Maurer, A. & Fenske,
D. (1988). Z. Naturforsch. Teil B, 43, 138–144.
C1—N1
P1—N1
P1—C7
P1—C13
P1—C19
1.372 (3)
1.5729 (18)
1.808 (2)
1.803 (2)
1.803 (2)
1.365 (2)
1.386 (2)
1.5752 (15)
1.8107 (17)
1.8015 (17)
1.8051 (17)
1.5622 (16)
1.816 (3)
1.799 (2)
1.8071 (19)
Coates, G. W., Dunn, A. R., Henling, L. M., Ziller, J. W., Lobkovsky, E. B. &
Grubbs, R. H. (1998). J. Am. Chem. Soc. 120, 3641–3649.
Ding, M. W., Huang, N. Y. & He, H. W. (2005). Synthesis, pp. 1601–1604.
Ding, M. W., Xu, S. Z. & Zhao, J. F. (2004). J. Org. Chem. 69, 8366–8371.
Ding, M. W., Zeng, G. P. & Wu, T. J. (2000). Synth. Commun. 30, 1599–
1604.
C1—N1—P1
N1—P1—C7
N1—P1—C13
N1—P1—C19
131.35 (15)
113.44 (10)
106.12 (10)
116.93 (10)
131.16 (12)
117.17 (8)
104.86 (9)
113.77 (8)
128.93 (13)
112.56 (18)
107.72 (8)
116.08 (9)
C6—C1—N1—P1
C1—N1—P1—C7
C1—N1—P1—C13
C1—N1—P1—C19
1.1 (3)
78.4 (2)
165.70 (19)
48.5 (2)
0.2 (3)
14.7 (3)
À71.1 (2)
172.32 (15)
54.46 (19)
43.30 (19)
161.58 (16)
82.24 (17)
Eguchi, S. (2005). Arkivoc, 2, 98–119.
Enraf–Nonius (1989). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Nether-
lands.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.
Hakansson, M., Jagner, S., Sundahl, M. & Wennerstrom, O. (1992). Acta Chem.
Scand. 46, 1160–1165.
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
Hewlins, M. J. E. (1971). J. Chem. Soc. B, pp. 942–945.
Irngartinger, J., Lichtenthaler, J. & Herpich, R. (1994). Struct. Chem. 5, 283–
289.
Kurzer, F. & Douraghi, K. (1967). Chem Rev. 67, 107–152.
Liu, J. C., He, H. W., Ren, Q. Y. & Ding, M. W. (2006). J. Heterocycl. Chem. 43,
803–806.
Llamas-Saiz, A. L. & Foces-Foces, C. (1994). Acta Cryst. C50, 255–259.
´
Llamas-Saiz, A. L., Foces-Foces, C., Elguero, J., Molina, P., Alajarın, M. &
˚
0.99 (2) A; Uiso(H) values were constrained to 1.5Ueq(C). When not,
they were placed in calculated positions and refined as riding with
˚
C—H distances of 0.93 A and with Uiso(H) = 1.2Ueq(C). Ring B of the
triphenylphosphine group in compound (III) was disordered. The
displacement parameters of the atoms in the minor conformer were
restrained to be the same as for the corresponding atoms in the major
conformer. Furthermore, the P1—C7 and P1—C97 distances were
˚
restrained to be equal within a standard uncertainty of 0.02 A. The
disorder involves a rotation of the ring of approximately 40ꢀ around
the axis through C7Á Á ÁC10, which atoms are not drastically displaced
by the disorder, as shown in Fig. 1. Site-occupancy factors are
0.791 (3) and 0.209 (3) for the major and minor conformers, respec-
tively. The major form is obviously energetically more favourable,
since the C8—H8Á Á ÁO2vi and C9—H9Á Á ÁO2vi contacts [symmetry
code: (vi) x À 1, y À 1, z À 1] seen in the major conformer are absent
in the minor conformer.
Vidal, A. (1992). Acta Cryst. C48, 1940–1945.
Mikolajczyk, M. & Kielbasinski, P. (1981). Tetrahedron, 37, 233–284.
¨
Mullen, K. & Wegner, G. (1998). Electronic Materials – the Oligomer
Approach. Weinheim: Wiley VCH.
Nohra, B., Graule, S., Lescop, C. & Reau, R. (2006). J. Am. Chem. Soc. 128,
3520–3521.
Okawa, T., Eguchi, S. & Kakehi, A. (1996). J. Chem. Soc. Perkin Trans. 1, pp.
247–254.
Renak, M. L., Bartholomew, G. P., Wang, S. J., Ricatto, P. J., Lachicotte, R. J. &
Bazan, G. C. (1999). J. Am. Chem. Soc. 121, 7787–7799.
For all compounds, data collection: CAD-4 EXPRESS (Enraf–
Nonius, 1989); cell refinement: CAD-4 EXPRESS; data reduction:
XCAD4 (Harms & Wocadlo, 1995). Program(s) used to solve struc-
ture: SHELXS86 (Sheldrick, 2008) for (I) and (II); SHELXS97
(Sheldrick, 2008) for (III). For all compounds, program(s) used to
refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics:
ORTEP-3 for Windows (Farrugia, 1997); software used to prepare
material for publication: WinGX (Farrugia, 1999).
´
Sancho-Garcia, J. C., Bredas, J. L., Beljonne, D., Cornil, J., Martinez-Alvarez,
R., Hanack, M., Poulsen, L., Gierschner, J., Mack, H. G., Egelhaaf, H. J. &
Oelkrug, D. (2005). J. Phys. Chem. B, 109, 4872–4880.
Segura, J. L. & Martin, N. (2000). J. Mater. Chem. 10, 2403–2435.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Ulrich, H. & Sayigh, A. A. R. (1966). Angew. Chem. Int. Ed. 5, 704–712.
Vande Velde, C. M. L., Baeke, J. K., Geise, H. J. & Blockhuys, F. (2005). Acta
Cryst. C61, o284–o287.
Vande Velde, C. M. L., Chen, L. J., Baeke, J. K., Moens, M., Dieltiens, P., Geise,
H. J., Zeller, M. & Blockhuys, F. (2004). Cryst. Growth Des. 4, 823–830.
Vande Velde, C. M. L., De Borger, R. & Blockhuys, F. (2005). Acta Cryst. E61,
o4289–o4291.
Vande Velde, C. M. L., Geise, H. J. & Blockhuys, F. (2005). Acta Cryst. C61,
o21–o24.
Vande Velde, C. M. L., Geise, H. J. & Blockhuys, F. (2006). Cryst. Growth Des.
6, 241–246.
Wamhoff, H., Herrmann, S., Stolben, S. & Nieger, M. (1993). Tetrahedron, 49,
581–594.
Yuan, J. Z., Fu, B. Q., Ding, M. W. & Yang, G. F. (2006). Eur. J. Org. Chem. pp.
4170–4176.
RDB and AC thank the Institute for the Promotion of
Innovation through Science and Technology in Flanders
(IWT–Vlaanderen) for a research grant. Financial support by
FWO–Vlaanderen under grant No. G.0129.05 and by the
University of Antwerp under grant No. GOA-2404 is grate-
fully acknowledged.
Zeller, M., Hunter, A. D., Hoefnagels, R., Geise, H. J. & Blockhuys, F. (2005).
Acta Cryst. E61, o4183–o4184.
Zhao, J. F., Xie, C., Xu, S. Z., Ding, M. W. & Xiao, W. J. (2006). Org. Biomol.
Chem. 4, 130–134.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: UK3009). Services for accessing these data are
described at the back of the journal.
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o54 De Borger et al.
C25H19N2P, C24H19N2O2P and C24H19N2O2P
Acta Cryst. (2010). C66, o50–o54