Synthesis and crystal structure of tris(2,3-triphenylenedioxy) cyclotriphosphazene: A new clathration system

Article abstract of DOI:10.1039/c1ce05529a

A new host compound TTPP (tris(2,3-triphenylenedioxy)cyclotriphosphazene), which is able to form a porous network, has been synthesized in five steps. When it crystallizes as a single component, TTPP exhibits a crystal structure with a monoclinic unit cell, the space group P2₁/c (no. 14) and unit cell dimensions of a = 14.909(2) A, b = 31.013(4) A, c = 9.074(1) A, β = 102.12(1)°. Co-crystallization of TTPP with 1,2,4-trichlorobenzene forms an inclusion crystal having a triclinic unit cell with a P1 space group (no. 2) and unit cell dimensions of a = 8.769(2) A, b = 15.024(2) A, c = 21.216(2) A, α = 94.82(0)°, β = 99.98(0)°, γ = 98.23(1). The guest lies in two kinds of channel-like cavities with dimensions of 6.1 × 8.4 A² and 10.7 × 12.4 A² respectively. This represents the biggest porous network built up by spirocyclotriphosphazene derivatives to date.

Full text of DOI:10.1039/c1ce05529a

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PAPER
Synthesis and crystal structure of tris(2,3-triphenylenedioxy)
cyclotriphosphazene: a new clathration system†
a
a
a
b
a
Mathias Reynes, Olivier J. Dautel,* David Virieux, David Flot and Jo €e l J. E. Moreau*
Received 21st April 2011, Accepted 21st June 2011
DOI: 10.1039/c1ce05529a
A new host compound TTPP (tris(2,3-triphenylenedioxy)cyclotriphosphazene), which is able to form
a porous network, has been synthesized in five steps. When it crystallizes as a single component, TTPP
exhibits a crystal structure with a monoclinic unit cell, the space group P2
ꢀ
1
/c (no. 14) and unit cell
ꢀ
ꢀ
ꢀ
dimensions of a ¼ 14.909(2) A, b ¼ 31.013(4) A, c ¼ 9.074(1) A, b ¼ 102.12(1) . Co-crystallization of
ꢁ
TTPP with 1,2,4-trichlorobenzene forms an inclusion crystal having a triclinic unit cell with a P1 space
ꢀ
ꢀ
ꢀ
group (no. 2) and unit cell dimensions of a ¼ 8.769(2) A, b ¼ 15.024(2) A, c ¼ 21.216(2) A, a ¼ 94.82
ꢀ
ꢀ
(
0) , b ¼ 99.98(0) , g ¼ 98.23(1). The guest lies in two kinds of channel-like cavities with dimensions of
ꢀ
2
ꢀ
2
6
.1 ꢁ 8.4 A and 10.7 ꢁ 12.4 A respectively. This represents the biggest porous network built up by
spirocyclotriphosphazene derivatives to date.
1
5,16
Introduction
enedioxy)cyclotriphosphazene (TNP)
and tris(9,10-phenan-
17
threnedioxy)cyclotriphosphazene (TPhenP).
Spirocyclic triphosphazene derivatives are known to form host–
guest inclusion compounds with a wide variety of organic or
1
inorganic molecules. In their unique paddle-wheel shapes,
Typical syntheses involve the reaction of aryldioxy reagents
with the reactive hexachlorocyclotriphosphazene. Interestingly
the host can be tailored by using the appropriate aromatic diol
paddles. TNP hosts form inclusion compounds with the same
hexagonal structure but with larger channel sizes. Thus, tunnel
diameter can be easily tuned by enhancing aryldioxy paddle
length from catechol to naphthalenediol: channel diameters are
aromatic units are perpendicularly oriented to the central
cyclotriphosphazene hub. This feature permits the formation of
channel walls, which are set up by planar aromatic entities. The
bulky shape associated with molecular rigidity can be connected
to the formation of inclusion compounds featuring properties
often associated with inorganic zeolites. The oldest member of
ꢀ
ꢀ
respectively 5 A and 10 A for TPP and TNP. The latter, having
larger pores, allows inclusion and polymerization of bigger
guests such as octyl acrylate that cannot be included in TPP for
this family, and probably also the most widely studied, is the tris
2
o-phenylenedioxy)cyclotriphosphazene (TPP). The formation
(
18
polymerization or separation. Moreover, enlarged pores favor
of inclusion compounds with this host leads to hexagonal
structures in which guest molecules occupy crystalline channels
guest–guest interactions which could be an important feature for
monomer polymerizations and conductance properties of guest
6,18
ꢀ
3,4
of 5 A width. The TPP host can also selectively discriminate
species.
small molecules or polymers based on their size, shape, aroma-
With the aim of increasing pore sizes, Allcock et al. synthesized
TPhenP and obtained different inclusion structures depending
17
5–9
ticity or even acidity. TPP has also been used as a template for
inclusion polymerization of various vinyl, diene or acrylate
13
Porosity has been studied for gas storage and
on the nature of the molecular guest. Two of those structures
10–12
monomers.
are reported but none of them correspond to TPP nor TNP
17
structures. TPhenP host also gives networks presenting tunnel-
inclusion of iodine shows that semi-conducting properties can be
14
brought to such materials.
like cavities. When o-dichlorobenzene is included, channel
ꢀ
dimensions are approximately 5.8 A large and 6.4 A in width.
So far, Allcock et al. have reported the synthesis and inclusion
behavior of several host molecules including tris(o-phenyl-
ꢀ
When p-xylene is included, two kinds of channel are formed with
ꢀ
sizes of approximately 5.91 A and 7.3 A.
2,5
enedioxy)cyclotriphosphazenes (TPP),
tris(2,3-naphthal-
ꢀ
The present work reports the synthesis of a new host
compound,
tris(2,3-triphenylenedioxy)cyclotriphosphazene
a
Architectures Mol eꢂ culaires et Mat eꢂ riaux Nanostructur eꢂ s, Institut Charles
Gerhardt Montpellier, UMR CNRS 5253, Ecole Nationale Sup eꢂ rieure de
Chimie de Montpellier, 8 rue de l’Ecole Normale F-34296, Montpellier
Cedex 05, France. E-mail: olivier.dautel@enscm.fr; Fax: +33 4 6714
(
TTPP), and the elaboration of the related porous network. The
design of such a host is motivated by three main objectives:
firstly, to elaborate new porous networks with cavity sizes bigger
than those previously reported for spirocyclic triphosphazenes;
secondly, to investigate if networks based on the same topology
as TPhenP can be obtained while enhancing cavity size; and
7
b
217; Tel: +33 4 6714 7212
ESRF, 6, rue Jules Horowitz, BP181, 38042 Grenoble Cedex 9, France
† CCDC reference numbers 812014–812015. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c1ce05529a
6
050 | CrystEngComm, 2011, 13, 6050–6056
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0
0
0
0
00
thirdly, to increase the stability of the porous network by
enhancing p-stacking interactions between host walls. According
to these objectives, TTPP appears to be a valuable target.
Synthesis of 4 ,5 -dimethoxy-1,1 :2 ,1 -terphenyl, 2
Into a round bottom flask were introduced successively
1
,2-dibromo-4,5-dimethoxybenzene 1 (5.92 g, 20 mmol), phe-
nylboronic acid (7.32 g, 60 mmol), toluene (50 mL) and sodium
carbonate (6.36 g, 60 mmol) in water (30 mL). Nitrogen was
ꢀ
bubbled into the mixture for 2 h at 60 C. The catalyst (Pd
(
3 4
PPh ) , 924 mg, 0.8 mmol) was then added and the reaction
mixture was stirred for 23 h at reflux. Toluene was evaporated
and the crude residue was extracted three times with CH Cl . The
2
2
organic layers were combined and evaporated. Subsequent
elution from silica gel with a dichloromethane–pentane mixture
as eluent (50 : 50 then 60 : 40) gave the desired product. After
concentration, the product was recrystallized in cyclohexane
1
giving colorless crystals (5.65 g, 97% yield). NMR H (CDCl
3
,
4
00 MHz): d (ppm) ¼ 7.18 (m, 10H); 6.95 (s, 2H); 3.95 (s, 6H);
NMR C (CDCl
, 100 MHz): d (ppm) ¼ 148.12 (2C); 141.40
2C); 132.97 (2C); 129.94 (4CH); 127.86 (4CH); 126.26
2CH);113.58 (2CH); 56.04 (2CH ); HRMS (TOF ES+) [M +
): calculated: 291.1385; found: 291.1370.
13
3
(
(
3
+
18 2
H] (C20H O
Synthesis of 2,3-dimethoxytriphenylene, 3
0
0
0
0
00
Into a Schlenk tube were introduced 4 ,5 -dimethoxy-1,1 :2 ,1 -
terphenyl 2 (2.32 g, 8 mmol) and anhydrous FeCl
0 mmol). The Schlenk tube was purged three times with
nitrogen and anhydrous CH Cl (130 mL) and nitromethane
3
(3.24 g,
2
2
2
(
5 mL) were added. The reaction mixture was stirred for 5 h at
room temperature. Methanol (80 mL) and water (80 mL) were
added and stirred for five minutes. Organic solvents were evap-
orated and the resulting mixture was extracted three times with
CH
dried over NaSO
resulting solid was solubilized in a minimum amount of CH
2
Cl
2
. Organic layers were combined, washed with water,
and evaporated under reduced pressure. The
Cl
4
2
2
and filtered through a silica plug. After concentration, the
product was recrystallized from toluene giving white crystals
1
(
(
1.93 g, 83% yield). NMR H (CDCl , 400 MHz): d (ppm) ¼ 8.66
3
m, 2H); 8.50 (m, 2H); 7.99 (s, 2H); 8.38 (m, 4H); 4.13 (s, 6H);
13
NMR C (CDCl , 100 MHz): d (ppm) ¼ 149.41 (2C); 129.46
3
(
2C); 129.14 (2C); 127.03 (2CH); 126.27 (2CH); 124.15 (2C);
23.39 (2CH); 122.74 (2CH); 104.47 (2CH); 55.97 (2CH );
): calculated: 289.1229;
1
3
HRMS (TOF ES+) (M + 1) (C20
16 2
H O
found: 289.1233.
Experimental section
Synthesis of triphenylene-2,3-diol, 4
Synthesis of 1,2-dibromo-4,5-dimethoxybenzene, 1
Into a Schlenk tube was introduced 2,3-dimethoxytriphenylene 3
A solution of Br
added dropwise to a solution of 1,2-dimethoxybenzene (9.67 g,
0 mmol, 8.9 mL) in CCl (200 mL) and the mixture was stirred
2
(33.56 g, 210 mmol) in CCl
4
(100 mL) was
(577 mg, 2 mmol). The Schlenk tube was purged three times with
2 2
nitrogen and anhydrous CH Cl (60 mL) was added. The
ꢀ
7
4
mixture was cooled at ꢂ78 C under a nitrogen atmosphere. A
for 3 days at room temperature. The excess of bromine was then
3 2 2
solution of 1M BBr in CH Cl (8 mL, 8 mmol) was added
neutralized by adding a solution of sodium metabisulfite in water
ꢂ1
dropwise. The reaction mixture was stirred while the temperature
ꢀ
(
0.5 mol L ). The solution was extracted three times with
rose slowly from ꢂ78 C to room temperature. The excess of
CH Cl . The organic layers were combined, washed with water,
2
BBr was destroyed by reaction with water. The reaction mixture
3
2
dried over NaSO and concentrated under reduced pressure to
4
was extracted three times with CH Cl and with ether. Organic
2
2
yield 1,2-dibromo-4,5-dimethoxybenzene 1 (20.50 g, 69 mmol) as
1
a white powder (99% yield). NMR H (CDCl , 400 MHz):
layers were combined, washed with water, dried over NaSO and
4
evaporated under reduced pressure. The resulting solid was
solubilized in hot toluene and filtered. Recrystallisation from
toluene gave the desired white product (470 mg, 90% yield).
3
13
d (ppm) ¼ 7.04 (s, 2H); 3.84 (s, 6H); NMR C (CDCl
MHz): d (ppm) ¼ 148.88 (2C); 115.93 (2CH); 114.76 (2C); 56.27
2CH ).
3
, 100
1
(
3
NMR H (DMSO-d6, 400 MHz): d (ppm) ¼ 9.65 (s, 2H); 8.72 (m,
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1
3
2
2
H); 8.43 (m, 2H); 8.01 (s, 2H); 7.61 (m, 4H); NMR C (DMSO-
d6, 100 MHz): d (ppm) ¼ 146.76 (2C); 129.12 (2C); 128.07 (2C);
27.27 (2CH); 125.97 (2CH); 123.42 (2CH); 122.75 (2C); 122.57
2CH); 108.48 (2CH).
pixels and a pixel size of 0.073254 ꢁ 0.073254 mm ). The
measurements were carried out at a fixed temperature of 100(2)
K using an Oxford 700 Cryostream device.
1
(
X-ray diffraction
Synthesis of tris(2,3-triphenylenedioxy)cyclotriphosphazene, 5
Structure solution and refinement. The frames were indexed
20
and the reflections integrated using the XDS software suite.
Into a Schlenk tube were introduced triphenylene-2,3-diol 4
(
729 mg, 2.8 mmol), hexachlorocyclotriphosphazene (325 mg,
.93 mmol) and potassium carbonate (774 mg, 5.6 mmol). The
Each reflection intensity was corrected from the action of
intensity loss due to air absorption. XDS (in the CORRECT
step) applies Lorentz and polarization factors as well as factors
which partially compensate from damage and absorption effects
to intensities and standard deviations of all reflections. These
factors were determined from many symmetry-equivalent
reflections usually found in the data images such that their
integrated intensities become as similar as possible. Therefore,
due to the small scattering volume of the crystal, absorption
effects due to the crystal itself are expected to be very weak.
The crystal structure of the non-hydrogen atoms was deter-
0
Schlenk tube was purged three times with nitrogen and anhy-
drous THF was added (125 mL). The reaction mixture was
ꢀ
stirred for 4.5 days at 40 C. Solvent was evaporated and the
resulting solid was washed twice with water and then with
methanol. After recrystallisation in o-dichlorobenzene, the
desired product was obtained as a white solid (641 mg, 76%).
31
NMR P (o-dichlorobenzene-d6, 400 MHz): d (ppm) ¼ 35 (3P);
HRMS (TOF ES+) (C H N O P ): calculated: 909.135; found:
5
4
30
3
6 3
9
09.026.
21
mined by direct methods using SHELXS97. Refinement was
carried out with SHELXL97. After a few least-squares cycles,
anisotropic displacement parameters were employed on all N, P,
O and C atoms. The hydrogen atoms were placed in idealized
Crystal preparation
a) Guest free crystals of TTPP 5. Compound 5 was dissolved
in hot tetrahydronaphthalene until the solubility limit was
reached. The hot solution was filtered and the filtrate was
introduced into a sealed tube. Crystals were grown by slow
ꢀ
positions with C–H ¼ 0.95 A during the refinement. Rings were
refined without any constraints. SHELXS97 and SHELXL97
22
were used through the WinGX Graphical User Interface.
ꢀ
ꢀ
ꢂ1
cooling from 200 C to room temperature at a rate of 1 C h .
Crystal data for TTPP 5
b) 1,2,4-trichlorobenzene–TTPP 5 inclusion adduct. The same
procedure as for the guest free crystals was followed using
ꢀ
C
54
H
30
N
3
O
ꢀ
6
P
3
, monoclinic, P2
ꢀ
1
/c (no.14), a ¼ 14.909(2) A, b ¼
1
,2,4-trichlorobenzene instead of tetrahydronaphthalene.
ꢀ
ꢀ
3
3
1.013(4) A, c ¼ 9.0740(1) A, b ¼ 102.120(7) , V ¼ 4102.05(9) A ,
T ¼ 100(2) K, R
1
¼ 0.0401 for 6340 independent observed
X-ray diffraction
ꢀ
reflections [F > 4s(Fo)], S ¼ 1.027. Data collection: 4 scans, 2
oscillation range, 1 pass of 2.5 s exposure time per image,
ꢀ
Data collection. Because of the small crystal volume and small
scattering power, synchrotron radiation was required for struc-
ture determination. Microdiffraction patterns were recorded at
the ID23-2 structural biology microfocus beamline (European
Synchrotron Radiation Facility - ESRF, Grenoble) where the
1
20 images, l ¼ 0.8726 A, 16 bunch mode.
Crystal data for 1,2,4-trichlorobenzene-TTPP 5 inclusion adduct
ꢁ
ꢀ
C
54
H
29
N
2
O
6
P
3
, 2 C
6
3
H Cl
3
triclinic, P1 (no.2), a ¼ 8.769(2) A,
19
beam is focussed down to approximately 8 mm in diameter.
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
b ¼ 15.024(2) A, c ¼ 21.216(2) A, a ¼ 94.818(3) , b ¼ 99.983(5) ,
Each sample was mounted on a nylon loop embedded with
Paratone oil from Hampton Research (Fig. 1). Several crystals
were tested to select a single crystal of suitable quality for data
ꢀ
3
g ¼ 98.226(6) , V ¼ 2707.4(8) A , T ¼ 100(2)K, R ¼ 0.0669 for
1
6
770 independent observed reflections [F > 4s(Fo)], S ¼ 1.043.
ꢀ
Data collection: 4 scans, 3 oscillation range, 1 pass of 0.8 s
ꢀ
collection. The best TTPP 5 crystal was approximately 100 ꢁ 5
exposure time per image, 120 images, l ¼ 0.8726 A, 7/8 multi-
3
4 mm and the best 1,2,4-trichlorobenzene-TTPP 5 inclusion
ꢁ
bunch mode.
3
adduct crystal was approximately 250 ꢁ 10 ꢁ 10 mm . Data were
collected by the oscillation technique using a two-dimensional
2
CCD detector (marMOSAIC; ꢃ225 ꢁ 225 mm , 2048 ꢁ 2048
Results and discussion
TTPP 5 synthesis
Compound 5 was prepared in five steps starting from veratrol
(
Scheme 1). Bromination of veratrol by bromine afforded the
,2-dibromo-4,5-dimethoxybenzene (1) in 99% yield. Then, 1
1
underwent a double Suzuki coupling reaction with phenyl-
boronic acid in the presence of Pd(PPh ) and Na CO to obtain
3
4
2
3
0
0
0
0
00
the 4 ,5 -dimethoxy-1,1 :2 ,1 -terphenyl (2) in 97% yield. The
key step consisted of a cyclodehydrogenation of 2 mediated by
FeCl
3
to give 2,3-dimethoxytriphenylene (3) in 83% yield.
gave triphenylene-2,3-diol 4 in 90%
Fig. 1 Photographs of a) TTPP 5 crystal and b) 1,2,4-trichlorobenzene-
TTPP 5 inclusion adduct crystal on a nylon loop embedded with Para-
tone oil. The red cross indicates the beam position.
Deprotection of 3 by BBr
3
yield. The final step consisted of the trisubstitution reaction of
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Scheme 1 Five step synthesis of TTPP 5.
hexachlorocyclotriphosphazene by 4 to afford tris(2,3-tripheny-
lenedioxy)cyclotriphosphazene 5 in 76% yield.
TPhenP guest free structure has not been reported yet and
interestingly guest free-TNP crystallizes in a very different
manner. In the latter, paddles are not wide enough to interact by
p-stacking interactions and the structure is only stabilized by van
der Waals interactions, showing the benefits of the larger paddles
of the TPhenP.
Crystal structure
a) Guest free crystal structure. Guest free 5 crystallized alone
in a monoclinic unit cell with a space group of P2 /c (Fig. 2a).
1
Each unit cell has four TTPP molecules. This structure does not
contain any porosity in which guest molecules might accom-
modate. The packing arrangement is described by a columnar
arrangement along the c axis of interdigitated TTPP molecules
b) Crystal structure of 1,2,4-trichlorobenzene host–5 inclusion
adduct. When co-crystallized with an appropriate guest such as
1,2,4-trichlorobenzene, TTPP 5 forms an organic clathrate. Two
molecules of TTPP 5 and four of 1,2,4-trichlorobenzene are
ꢁ
disclosed in a triclinic unit cell with a P1 space group (Fig. 3).
(
Fig. 2b). Very short C–C distances could be observed between
ꢀ
TTPP molecules constituting the stacks (C(17)–C(52) ¼ 3.303 A
Host molecules interact by p–p stacking interactions and
show very short C–C distances between the overlapping aromatic
ꢀ
and C(17)–C(53) ¼ 3.418 A) suggesting a stabilization of the
ꢀ
ꢀ
columns by p–p stacking interactions along the c axis. However,
no short contacts could be observed between the columns. Only
van der Waals interactions take place in the ab plane. The
fragments (C(1)–C(11) ¼ 3.293 A and C(9)–C(17) ¼ 3.359 A).
Guest molecules lie in two kinds of tunnel-like cavities. The
dimensions of the smallest channel (Fig. 4, guest in red) are
Fig. 2 TTPP in guest free crystal structure unit cell: a) View down c-axis (p–p interactions between triphenylene units appear in red), b) View down a-
axis. Molecules present a columnar arrangement along c-axis. Molecules are colored for clarity.
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Fig. 3 Unit cell of 1,2,4-trichlorobenzene–5 adduct (p–p interactions between triphenylene units appear in red).
ꢀ
2
approximately 6.1 ꢁ 8.4 A at the widest point. Along this
channel, 1,2,4-trichlorobenzene molecules are stacked between
two adjacent triphenylene units in one type of environment.
However, four different orientations are possible. As a result,
disorder at the positions of the chlorine atoms is observed. Each
chlorine (Cl and Cl ) atom has an occupation rate of 0.75. The
different occupancies: Cl
Cl
¼ 0.8. Molecules located at the center of the channel have
two possible orientations. Disorder at chlorine positions is
modeled by occupancy factors of 1 for Cl and 0.5 for Cl
3
¼ 1, Cl
2
¼ 0.8, Cl
4
¼ 0.2, Cl ¼ 0.2 and
5
1
6
7
.
This structure is comparable to the one reported for the
TPhenP inclusion compound of p-xylene which presents two
different kinds of channel. However, longer paddles offer larger
pore sizes, which permit the inclusion of three molecules of
solvent instead of the two reported in literature.
8
9
dimensions of the biggest channel (Fig. 4, guest in blue) are
ꢀ
2
approximately 10.7 ꢁ 12.4 A at the widest point. Three guest
molecules in the same plane have two different environments:
two molecules in the closest positions from the cavity walls are
stacked with their adjacent triphenylene unit, and one molecule
in the center of the tunnel-like cavities lies between the other two
guest molecules.
Molecular structures
Molecules located at the channel periphery have two different
possible orientations, with one preferred over the other with
a ratio of 80/20. Disorder at chlorine positions is modeled with
Aromatic side groups lie perpendicular to the plane of the
phosphazene ring according to the tetrahedral geometry of the
phosphorus atoms (Fig. 5 and Fig. 6). TTPP molecules have
a radial distribution of triphenylene units with an almost 3-fold
arrangement for both guest free and guest containing structures.
This orientation is known to be a consequence of the spi-
rocyclic 5-membered ring strain and was already reported for
4,16,17
TPP, TNP and TPhenP molecules.
However, this particular
behavior is generally not observed for guest free structures.
For example, TNP adopts a very different geometry when
23
3
crystallized alone. Interactions and C geometry do not match
each other. In order to stabilize the network structure, TNP
molecules lose their 3-fold arrangement. Side groups are bent
away at the oxygen atom and a compact packing is obtained.
However, when TNP molecules are co-crystallized with guest
compounds such as benzene, a hexagonal lattice is formed in
which the C
3
-symmetry is retained by stabilizing host–guest
Fig. 4 Tunnel-like cavities containing guest molecules.
interactions and by guest ‘‘cushioning’’.
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ꢀ
Table 2 Bond lengths (A) and bond angles (deg) in TTPP in 1,2,4-tri-
chlorobenzene-TTPP structure (mean values)
P–N
P–O
N–P–N
P–N–P
O–P–O
1.583
1.620
117.3
122.4
97.3
O–C
C–C
N–P–O
P–O–C
O–C–C
1.398
1.388
110.1
109.4
111.9
between each TTPP within the columnar arrangement. For
,2,4-trichlorobenzene inclusions, the phosphazene ring is planar
1
indicating that in this lattice, hosts are less constrained.
Conclusions
A porous network based on a cyclotriphosphazene core has been
elaborated from tris(2,3-triphenylenedioxy)cyclotriphosphazene
(TTPP) as the host. TTPP exhibits larger channel sizes than
those previously reported. The porosity of the 1,2,4-tri-
chlorobenzene–TTPP inclusion adduct has been modulated
compared to the p-xylene–TPhenP adduct while maintaining the
same topology. Since the inclusion compound is stabilized by
p–p stacking interactions, a better stability is expected. Studies
of the structural stability are currently in progress. In parallel, the
influence of guest molecules on the TTPP crystal structure,
optical and conductive properties are also under investigation.
Fig. 5 Molecular structure of TTPP in 1,2,4-trichlorobenzene–TTPP 5
inclusion adduct.
Acknowledgements
The authors gratefully acknowledge financial support from the
‘Minist ꢃe re de la Recherche’’; the CNRS and the Languedoc-
‘
Roussillon region are acknowledged for providing M. R. with
a doctoral training grant. We gratefully acknowledge the allo-
cation of beam time for the experiment at the ID23-2 beamline at
the European Synchrotron Radiation Facility
Grenoble.
- ESRF,
This work was supported by the ANR-07-JCJC-0022 grant/
Fig. 6 Molecular structure of TTPP 5 in guest free crystal structure.
NANOTECTUM and the TRIMATEC competitiveness cluster.
Notes and references
Interatomic distances and angle values are comparable for
TTPP molecules in both crystal structures and are close to those
reported for the TNP host in guest containing hexagonal struc-
tures. Mean values for triphosphazene and five-membered spi-
rocyclic rings are reported in Table 1 and Table 2.
1 H. R. Allcock, Acc. Chem. Res., 1978, 11, 81–87.
2 H. R. Allcock, J. Am. Chem. Soc., 1964, 85, 4050–4051.
3
4
L. A. Siegel and J. H. van den Hende, J. Chem. Soc. A, 1967, 817–820.
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There is however a noteworthy difference in the TTPP
molecular structure between the two crystal structures. In the
guest free crystal, triphenylene side groups are oriented above
and below the cyclotriphosphazene mean plane. Consequently,
the cyclotriphosphazene ring is slightly distorted in a boat like
conformation. This distortion comes from a p-interaction
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ꢀ
Table 1 Bond lengths (A) and bond angles (deg) in TTPP in guest free
crystal structure (mean values)
1
1
1
P–N
P–O
N–P–N
P–N–P
O–P–O
1.582
1.619
117.3
121.8
96.9
O–C
C–C
N–P–O
P–O–C
O–C–C
1.395
1.392
110.2
109.8
111.7
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