1-Chloro-1,3,3,5,5-pentaphenoxy-cyclotriphosphazene: A precursor of functionalized cyclophosphazene derivatives

Article abstract of DOI:10.1107/S0108270104018190

The crystal structure of the compound C₃H₂₅ClN ₃O₅P₃ was investigated. A small asymmetry within the bond angles of the phospazene ring was noted as was observed in the related cyclic (p-halogenophenoxy)-phosphazene structures. The mean values of the N-P-N and P-N-P angles were 117.87 and 121.54° respectively. The plane of phenoxy group C(C521-C526) attached to atom O52 was approximately perpendicular to the phosphazene ring with a dihedral angle of 78.59(9)°. A significant difference between the two P atoms was observed in the crystal structure and concerns the positions of phenoxy groups.

Full text of DOI:10.1107/S0108270104018190

organic compounds
ꢀ
21.54 , respectively. The PÐO, PÐN, PÐCl and OÐC bond
Acta Crystallographica Section C
Crystal Structure
Communications
1
lengths are in agreement with the values observed in ana-
logous structures deposited in the CSD (Table 3). It is inter-
esting to note that the occurrence of a Cl atom directly
attached to a P atom (P1) does not modify the structural
parameters in the vicinity of this atom.
ISSN 0108-2701
1
-Chloro-1,3,3,5,5-pentaphenoxy-
cyclotriphosphazene: a precursor of
functionalized cyclophosphazene
derivatives
a
b
Jana Sopkov a -de Oliveira Santos, * Diane Bauchart,
b
b
Celine Besset and Isabelle Dez
a
Â
Centre d'Etudes et de Recherche sur le M e dicament de Normandie (CERMN),
b
The benzene rings lie on both sides of the phospazene ring,
three on one side and two on the other, close to which lies the
Cl atom. The disposition of the three phenoxy side groups on
the side opposite to the Cl atom is such that the plane of
phenoxy group C (C521±C526) attached to atom O52 (on P5)
is approximately perpendicular to the phosphazene ring, with
Universit e de Caen, 5 rue Vaub e nard, 14032 Caen Cedex, France, and Laboratoire
de Chimie Mol e culaire et Thioorganique, UMR CNRS 6507, ENSICAEN, Universit eÂ
de Caen, 6 boulevard du Mar e chal Juin, 14050 Caen Cedex, France
Correspondence e-mail: sopkova@pharmacie.unicaen.fr
Received 26 April 2004
Accepted 23 July 2004
Online 25 September 2004
ꢀ
a dihedral angle of 78.59 (9) . Phenoxy ring B (C321±C326)
attached to atom O32 (on P3) is more tilted towards the
ꢀ
phosphazene ring, with a dihedral angle of about 69.52 (9) ,
and the third ring (A, C111±C116), attached to atom O11 (on
The crystal structure of the title compound, C H ClN O P ,
5 3
3
0
25
3
shows that the direct bonding between P and Cl does not
modify the structural parameters in the vicinity of this P atom.
It also con®rms the structural difference between the two P
atoms which are each bonded to two phenoxy groups,
P1), is nearly parallel to the phosphazene ring, with a dihedral
ꢀ
angle of 21.6 (2) . Furthermore, owing to optimization of CÐ
HÁ Á Áꢀ stacking interactions, these three benzene rings are
oriented so that they are approximately mutually perpendi-
cular. Benzene ring A is oriented perpendicular to benzene
3
1
observed in the P NMR spectrum. The crystal packing
consists principally of complex stacking interactions.
ꢀ
ring B, with a dihedral angle of about 89.6 (1) , and the
distance between atom C116 and the centroid of ring B, CgB,
Ê
is about 3.71 A (Table 4). Benzene ring B is perpendicular to
Comment
The title compound, (I), also known as monochloropenta-
phenoxycyclotriphosphazene, has already been used to
synthesize polymer precursors (Dez & De Jaeger, 1996). More
recently, it has been used to synthesize a wide range of
cyclotriphosphazene derivatives, such as cyclotriphosphazene
hydrazides (Chandrasekhar et al., 2003), cyclotriphosphazene
0
0
with N,N,N ,N -tetramethylguanidine groups (Bloy & Die-
fenbach, 2000), and cyclotriphosphazene with 2-, 3- and 4-py-
ridylmethoxy groups (Diefenbach et al., 1999). Its synthesis
and NMR data have been described elsewhere (Reuben, 1987;
Selvaraj et al., 1991). To date, however, structural data for (I)
are not available in the Cambridge Structural Database (CSD,
Version 5.24; Allen, 2002). We thus present here the results of
the ®rst X-ray crystal structure analysis of (I).
Fig. 1 shows a view of the asymmetric unit of (I), which
consists of one molecule. The phosphazene ring is planar, with
the maximum deviation from the mean least-squares plane
Ê
being 0.093 (1) A for atom P3. A small asymmetry within the
bond angles of the phospazene ring is noted (Table 1), as was
also observed in the related cyclic (p-halogenophenoxy)-
phosphazene structures (Allcock et al., 1994). The mean
values of the NÐPÐN and PÐNÐP angles are 117.87 and
Figure 1
A view of (I), showing the atom-labelling scheme. Displacement
ellipsoids are drawn at the 30% probability level and H atoms have
been omitted for clarity.
Acta Cryst. (2004). C60, o751±o753
DOI: 10.1107/S0108270104018190
# 2004 International Union of Crystallography o751

organic compounds
According to the geometric parameters, the C523Ð
H523Á Á ÁN6 interaction is weak, and it may be dif®cult to assert
the occurrence of a real CÐHÁ Á ÁN interaction.
Experimental
Hexachlorocyclotriphosphazene (1 g, 1 equivalent) in solution in
anhydrous tetrahydrofuran (THF) under nitrogen was stirred with
NaH (60% dispersion in mineral oil, 0.63 g, 5.5 equivalents) at 268 K.
A solution of phenol (1.49 g, 5.5 equivalents) in THF was added
dropwise to maintain the temperature at around 268 K. The mixture
was then stirred at room temperature for 24 h. The THF was
evaporated and the residue dissolved in dichloromethane, washed
with water and dried over anhydrous sodium sulfate. After removal
of the dichloromethane under reduced pressure, the yield reached
3
1
8
6% for (I), and the P NMR spectrum indicated the presence of
hexaphenoxycyclotriphosphazene as a side product. The title
compound was crystallized in a desiccator by slow diffusion of
31
pentane into a concentrated solution of (I) in THF. The P NMR
spectrum was recorded using a Bruker DRX400 and samples were
Figure 2
A general view of the crystal packing of (I), projected along the a axis.
dissolved in CDCl
3
to a concentration of 10% w/v.
Mo Kꢁ radiation
Crystal data
ꢀ
C
30
3 5 3
H25ClN O P
ring C, with a dihedral angle of 82.4 (1) , and the distance
between atom C326 and the centroid of ring C, CgC, is about
M
r
= 635.89
Orthorhombic, Pbca
Cell parameters from 25
re¯ections
Ê
.18 A (Table 4).
Ê
a = 9.8044 (7) A
b = 21.3628 (13) A
c = 29.2053 (15) A
Ê
V = 6117.0 (7) A
ꢀ
4
ꢂ = 18±21
ꢃ = 0.33 mm
T = 293 (2) K
Ê
Ê
� 1
On the same side as the Cl atom, benzene ring E (C311±
C316) attached to atom O31 is perpendicular to the phos-
3
Prism, colourless
0.52 Â 0.52 Â 0.41 mm
ꢀ
phazene ring, with a dihedral angle of 85.8 (1) , whereas
benzene ring D (C511±C516) attached to atom O51 is more
Z = 8
D
�
3
x
= 1.381 Mg m
tilted towards the phosphazene ring, with a dihedral angle of
ꢀ
Data collection
4
5.62 (6) . The dihedral angle between rings E and D
ꢀ
Enraf±Nonius CAD-4
diffractometer
ꢂ/2ꢂ scans
Absorption correction: Gaussian
ÏÂÏ Ï
(JANA98; Petrõcek & Dusek,
1998)
Rint = 0.077
ꢂmax = 30.0
ꢀ
[52.8 (1) ] indicates that these two rings are not in an optimal
perpendicular stacking interaction. However, atom C512 is
Ê
situated at a distance of 3.99 A from the centroid of ring E,
h = � 13 ! 13
k = 0 ! 30
l = 0 ! 41
CgE (Table 4).
Surprisingly, the P NMR spectrum of (I) shows a doublet
3 standard re¯ections
frequency: 60 min
intensity decay: 7.2%
3
1
T
min = 0.663, Tmax = 0.706
7 273 measured re¯ections
1
8884 independent re¯ections
of a doublet at 22.33 p.p.m. (JPNP = 81 and 84 Hz), attributed
to atoms P3 and P5, and a doublet at 7.03 p.p.m. (JPNP
=
3 Hz), attributed to P1, instead of the expected triplet (P3
4539 re¯ections with I > 2ꢄ(I)
8
Re®nement
and P5) and doublet (P1). These results indicate that P3 and
P5 are not strictly equivalent. A signi®cant difference between
these two P atoms is observed in the crystal structure and
concerns the positions of the phenoxy groups. This difference
could explain the non-equivalence observed for P3 and P5 in
the NMR spectrum.
2
2
2
2
Re®nement on F
2
o
w = 1/[ꢄ (F ) + (0.0617P)
2
R[F > 2ꢄ(F )] = 0.051
wR(F ) = 0.153
S = 1.01
8884 re¯ections
379 parameters
H-atom parameters constrained
+ 1.4945P]
where P = (F
(Á/ꢄ)max = 0.007
2
2
o
2
c
+ 2F
)/3
Ê
� 3
Áꢅmax = 0.37 e A
Áꢅmin = � 0.27 e AÊ �
3
In the crystal packing of (I), benzene rings from neigh-
bouring molecules complete the intramolecular stacking
interactions between the phenoxy units on both sides of the
phosphazene ring (Fig. 2). CÐHÁ Á Áꢀ interactions are observed
between rings E and B and between rings E and D. These
benzene rings make dihedral angles of 58.5 (1) and 70.9 (1) ,
respectively. For the former interaction, atom C325 is at a
Ê
distance of 3.90 A from CgE, and for the latter, atom C314 is
Table 1
Selected geometric parameters (A, ).
Ê
ꢀ
Cl1ÐP1
P1ÐN6
P1ÐO11
P1ÐN2
N2ÐP3
P3ÐN4
2.0064 (10)
1.561 (2)
1.5693 (19)
1.572 (2)
1.580 (2)
1.571 (2)
P3ÐO31
P3ÐO32
N4ÐP5
P5ÐO51
P5ÐN6
P5ÐO52
1.5830 (18)
1.5866 (17)
1.576 (2)
1.5711 (19)
1.576 (2)
1.5871 (19)
ꢀ
Ê
at a distance of 3.85 A from the centroid of ring D, CgD (Table
4
molecule is situated close to each N atom of the phosphazene
Ê
ring, at distances ranging from 3.35 to 3.67 A (Table 2).
). At the same time, a CÐH group from a symmetry-related
N2ÐP1ÐCl1
P1ÐN2ÐP3
N4ÐP3ÐN2
107.68 (9)
120.59 (12)
117.82 (11)
P3ÐN4ÐP5
N4ÐP5ÐN6
P1ÐN6ÐP5
121.74 (12)
117.12 (11)
122.30 (14)
o752 Jana Sopkov a -de Oliveira Santos et al.
ꢁ
C
30
H
25ClN
O P
5
Acta Cryst. (2004). C60, o751±o753
3
3

organic compounds
Table 2
Hydrogen-bonding geometry (A, ).
Data collection: CAD-4-PC Software (Enraf±Nonius, 1996);
cell re®nement: CAD-4-PC Software; data reduction: JANA98
Ê
ꢀ
(
Pet rÏ õÂ cÏ ek & Du sÏ ek, 1998); program(s) used to solve structure:
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
SHELXS97 (Sheldrick, 1990); program(s) used to re®ne structure:
SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3
i
C523ÐH523Á Á ÁN6
C315ÐH315Á Á ÁN4
C515ÐH515Á Á ÁN2
Symmetry codes: (i) ‡ x; y; � z; (ii) x �
0.93
0.93
0.93
2.69
2.89
3.05
3.352 (4)
3.621 (4)
3.672 (4)
129
136
126
ii
iii
(Farrugia, 1997); software used to prepare material for publication:
SHELXL97.
1
2
1
2
1
2
1
2
1
2
1
2
;
� y; � z; (iii) � x; y � ; z.
The authors gratefully acknowledge ®nancial support from
the Minist e re de la Recherche et des Nouvelles Technologies,
the CNRS (Centre National de la Recherche Scienti®que),
the R e gion Basse-Normandie and the European Union
(FEDER funding), and the CRIHAN for molecular modelling
software.
Table 3
Comparison of mean PÐN and PÐO distances (A) and PÐNÐP and
NÐPÐN angles ( ) in (I) and in reported cyclic (p-halogenophenoxy)-
phosphazene structures.
Ê
ꢀ
Compound
PÐN
PÐO
PÐNÐP
NÐPÐN
(
(
(
(
(
I)²
1.573
1.571
1.572
1.578
1.572
1.584
1.585
1.578
1.581
1.568
121.5
121.7
122.3
122.0
121.0
117.9
116.6
117.6
117.4
117.9
p-Bromophenoxy)phosphazene³
p-Chlorophenoxy)phosphazene³
p-Fluorophenoxy)phosphazene³
p-Iodophenoxy)phosphazene³
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: DN1053). Services for accessing these data are
described at the back of the journal.
²
This work. ³ Allcock et al. (1994).
References
Table 4
Geometry of selected CÐHÁ Á Áꢀ interactions in (I).
CgB is the centroid of the C321±C326 ring B, CgC is the centroid of the C521±
C526 ring C, CgD is the centroid of the C511±C516 ring D and CgE is the
centroid of the C311±C316 ring E.
Allcock, H. R., Ngo, D. C., Parvez, M. & Visscher, K. B. (1994). Inorg. Chem.
33, 2090±2102.
Allen, F. H. (2002). Acta Cryst. B58, 380±388.
Bloy, M. & Diefenbach, U. (2000). Z. Anorg. Allg. Chem. 626, 885±891.
Chandrasekhar, V., Andavan, G. T. S., Nagendran, S., Krishnan, V., Azhakar,
R. & Butcher, R. J. (2003). Organometallics, 22, 976±986.
Dez, I. & De Jaeger, R. (1996). J. Inorg. Organomet. Polym. 6, 111±121.
Diefenbach, U., Adamaszek, P. & Bloy, M. (1999). Heteroatom Chem. 10,
Ê
Distance (A)
ꢀ
CÐH (ring)
Centroid
Dihedral angle ( )
9
±15.
C116ÐH116 (A)
C326ÐH326 (B)
C512ÐH512 (D)
C323ÐH323 (B)
C314ÐH314 (E)
CgB
CgC
CgE
CgE
CgD
3.71
4.18
3.99
3.90
3.85
89.6 (1)
82.4 (1)
52.9 (1)
58.5 (1)
70.9 (1)
Enraf±Nonius (1996). CAD-4-PC Software. Version 2.0. Enraf±Nonius, Delft,
The Netherlands.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Pet rÏ õÂ cÏ ek, V. & Du sÏ ek, M. (1998). JANA98. Institute of Physics, Czech
Academy of Sciences, Prague, Czech Republic.
Reuben, J. (1987). Magn. Reson. Chem. 25, 1049±1053.
Selvaraj, I. I., Reddy, D., Chandrasekhar, V. & Chandrashekar, T. K. (1991).
Heterocycles, 32, 703±710.
i
ii
1
2
1
2
Symmetry codes: (i) � 1 � x, + y, � z; (ii) 1 + x, y, z.
H atoms were treated as riding, with CÐH distances in the range
Ê
.93±0.96 A and with Uiso(H) = 1.2Ueq(C).
Sheldrick, G. M. (1990). Acta Cryst. A46, 467±473.
Sheldrick, G. M. (1997). SHELXL97. University of G oÈ ttingen. Germany.
0
Acta Cryst. (2004). C60, o751±o753
Jana Sopkov a -de Oliveira Santos et al.
ꢁ
C
30
H25ClN O
3 5
P
3
o753