GaFPO3(C6H5): A new fluorinated gallium phenylphosphonate with a layered network

Article abstract of DOI:10.1107/S0108270102008934

Crystals of gallium fluorophenylphosphonate were synthesized hydrothermally at 453 K under autogenous pressure. The solid crystallizes in the monoclinic system and its structure is built up by the connection of zigzag chains of edge-sharing GaO₄F₂ octahedra to phenylphosphonate groups. This results in the formation of a layered structure, in which the phenyl groups point upward and downward from the inorganic sheet. The Ga atoms occupy the special positions 4a (inversion center) and 4e (twofold axis).

Full text of DOI:10.1107/S0108270102008934

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
non-aqueous solvents (Mason et al., 1997, 1998). The D4R
entity is analogous to the basic building block observed in
cloverite (Estermann et al., 1991) or ULM-5 (Loiseau & Ferey,
1994). In this context, we studied the reactivity of organo-
phosphonates with gallium in the presence of HF and water.
Two ¯uorinated gallium hydroxomethylphosphonates have
previously been identi®ed utilizing methylphosphonic acid
(Paulet et al., 1999). The structure of GaF0.72(OH)0.28(H2O)-
PO3CH3 is similar to that of the aluminium methyl-
phosphonate Al(OH)(H2O)PO3CH3 (Sawers et al., 1996) and
is based on the connection, by corner-sharing, of gallium
GaO3(OH,F)(H2O) octahedra with the tetrahedral CH3PO3
entity. A second solid, Ga3(OH)3F3PO3CH3 (MIL-23), built
up from the hexagonal arrangement of gallium Ga(OH,F)4O2
octahedra sharing corners with CH3PO3, was also reported.
The resulting structures were lamellar. Omitting F anions, the
preparation and structural characterization of layered gallium
methylphosphonates and gallium phenylphosphonates have
been described recently (Bujoli-Doeuff et al., 2000; Morizzi et
al., 2000). Both compounds have a two-dimensional network
formed by in®nite straight chains of edge-sharing gallium
GaO2(OH)4 octahedra linked to each other through PO3CH3
groups. Similar inorganic networks are observed in gallium
ethylenediphosphonic acid (Bujoli-Doeuff et al., 2001) and in
gallium phosphate intercalated with ethylenediamine (Jones et
al., 1991). The present paper deals with the synthesis and
structural characterization of a ¯uorinated gallium phenyl-
phosphonate, which exhibits a lamellar structure (Figs. 1
and 3). The Ga atoms are octahedrally coordinated to four O
and two F atoms, the F atoms occupying trans positions. Both
Ga atoms are on special positions; Ga2 lies on an inversion
center (4a), whereas Ga1 is located on a twofold axis (4e). The
gallium octahedra are connected to each other by a shared
edge composed of one F and one O atom, generating in®nite
zigzag chains running along [001] with a cis±trans sequence.
The gallium chains are linked to each other via phenyl-
phosphonate groups (Fig. 2). Two O atoms of the PO3 species
connect to two adjacent gallium octahedra belonging to the
same chain, whereas the third O atom links Ga atoms from a
different chain. This GaÐOÐP connection mode ensures the
cohesion of the inorganic sheet. One of the O atoms (O3) is
ISSN 0108-2701
GaFPO3(C6H5): a new fluorinated
gallium phenylphosphonate with a
layered network
Thierry Loiseau,a*² Sharma Neerajb and Anthony K.
Cheethamb
a
Â
Institut Lavoisier, IREM, UMR CNRS C 8637, Universite de Versailles Saint-Quentin-
en-Yvelines, 45 Avenue des Etats Unis, 78035 Versailles Cedex, France, and
bMaterials Research Labaratory, University of California at Santa Barbara, Santa
Barbara, 93106 CA, USA
Correspondence e-mail: loiseau@chimie.uvsq.fr
Received 30 April 2002
Accepted 17 May 2002
Online 12 June 2002
Crystals of gallium ¯uorophenylphosphonate were synthe-
sized hydrothermally at 453 K under autogenous pressure. The
solid crystallizes in the monoclinic system and its structure is
built up by the connection of zigzag chains of edge-sharing
GaO4F2 octahedra to phenylphosphonate groups. This results
in the formation of a layered structure, in which the phenyl
groups point upward and downward from the inorganic sheet.
The Ga atoms occupy the special positions 4a (inversion
center) and 4e (twofold axis).
Comment
Metal organophosphonates are a class of materials with
diverse structural varieties, displaying properties in the ®elds
of catalysis, ion exchange and non-linear optics. Their versa-
tility comes from the possibility of incorporating different
organic groups into an inorganic matrix composed of di-, tri-
or tetravalent metal phosphonate (Clear®eld, 1996). More
recently, these phosphonates have been used for the synthesis
of molecular solids whose structures resemble the secondary
building units (SBUs) encountered in the microporous phos-
phate family (Mason et al., 1996). Despite the successful
syntheses of a large number of open-framework phosphates
(Cheetham et al., 1999), the formation mechanisms which
occur during the hydrothermal treatment are still poorly
understood. For example, several reports have been devoted
to the synthesis of microporous ¯uorinated gallium phos-
phates exhibiting extra-large pore systems (Estermann et al.,
1991; Sassoye et al., 2000). The isolated clusters prepared using
the phosphonate route might act as molecular precursors in
the formation of three-dimensional networks. For the gallium
phosphonate system, the four-ring unit Ga2P2O4 (4R) and the
double four-ring unit Ga4P4O12 (D4R) have been isolated in
Figure 1
Projection of the structure of GaFPO3(C6H5) along [010], showing the
connection of the GaFPO3C sheets to the phenyl groups. The phenyl
species are statistically oriented in the (101) or (110) planes.
² On sabbatical leave at: Materials Research Labaratory, University of
California at Santa Barbara, Santa Barbara, 93106 CA, USA.
Acta Cryst. (2002). C58, m379±m381
DOI: 10.1107/S0108270102008934
# 2002 International Union of Crystallography m379

metal-organic compounds
aminopropane and deionized water in the molar ratio 1:5.3:7:2.5:290.
This mixture was sealed in a te¯on-lined Parr autoclave and heated
for 48 h at 453 K under autogenous pressure. The pH was 4 during the
synthesis. After cooling to room temperature, the solid was separated
from the liquid phase by ®ltration, washed with water and then dried
in air. A single crystal for the diffraction study was selected optically
and glued to a glass ®bre. The presence of ¯uorine in the gallium
bridging sites was con®rmed by the chemical analysis [%F
experimental = 7.4 (3); %F theoretical = 7.7]. This observation is in
agreement with bond-valence calculations (O'Keeffe & Brese, 1992).
Crystal data
3
GaFPO3(C6H5)
Mr = 244.79
Monoclinic, C2/c
Dx = 2.053 Mg m
Mo Kꢁ radiation
Cell parameters from 4648
re¯ections
Ê
a = 29.7810 (4) A
b = 5.42200 (10) A
ꢂ = 1.4±29.9ꢁ
ꢃ = 3.65 mm
T = 293 (2) K
Ê
1
Ê
c = 9.8768 (2) A
ꢀ = 96.6180 (10)ꢁ
3
Ê
V = 1584.21 (5) A
Z = 8
Figure 2
Needle, colourless
0.80 Â 0.08 Â 0.01 mm
Polyhedral representation of a GaFPO3C layer along [100], showing the
in®nite zigzag chain of gallium octahedra linked with phosphonate groups
(grey octahedra: GaO4F2; white tetrahedra: PO3C; black circles: carbon;
dark-grey circles: ¯uorine). The O atoms and the phenyl groups have
been omitted for clarity.
Data collection
Siemens SMART diffractometer
! scans
Absorption correction: empirical
(Blessing; 1995)
Tmin = 0.606, Tmax = 0.807
5433 measured re¯ections
2111 independent re¯ections
1797 re¯ections with I > 2ꢄ(I)
Rint = 0.034
ꢂmax = 29.9ꢁ
h = 40 ! 37
k = 6 ! 7
l = 13 ! 13
Re®nement
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.042
wR(F2) = 0.104
S = 1.14
2111 re¯ections
w = 1/[ꢄ2(Fo2) + (0.0476P)2
+ 6.8305P]
where P = (Fo2 + 2Fc2)/3
(Á/ꢄ)max < 0.001
3
Ê
Áꢅmax = 1.12 e A
3
Ê
0.99 e A
96 parameters
H-atom parameters constrained
Áꢅmin
Extinction correction: SHELXL97
=
Extinction coef®cient: 0.0007 (2)
Table 1
Selected interatomic distances (A).
Ê
Ga1ÐF
1.877 (2)
1.929 (3)
2.175 (2)
1.900 (2)
1.963 (2)
2.034 (2)
1.521 (2)
1.527 (3)
1.556 (2)
PÐC1
1.784 (4)
1.377 (11)
1.394 (7)
1.334 (13)
1.368 (15)
1.38 (2)
1.377 (13)
1.559 (10)
1.381 (10)
Ga1ÐO2i
Ga1ÐO3
Ga2ÐF
C1ÐC2
C1ÐC6
C4ÐC5
C4ÐC3
C2ÐC3
C5ÐC6
C21ÐC31
C51ÐC61
Figure 3
Ga2ÐO1ii
Ga2ÐO3iii
PÐO1
PÐO2iv
PÐO3
Displacement ellipsoid plot (50% probability) of the structure of
GaFPO3(C6H5) viewed along [010]. The phenyl species are statistically
oriented in the (101) or (110) planes.
Symmetry codes: (i) 1 x; y; 23 z; (ii) 1 x; 1 y; 2 z; (iii) x; 1 y; 12 ‡ z; (iv)
threefold coordinated and is characterized by longer cation±
anion distances. All the other anions are twofold coordinated,
with classical PÐO and GaÐ(O,F) bond distances (Table 1).
The inorganic arrangement of the layer is identical to that of
the gallium ¯uorophosphate MIL-35 (Sassoye et al., 2001)
obtained with 1,12-diaminododecane. The phenyl substituents
are oriented perpendicular to the sheet and are statistically
located in two positions related by a 90ꢁ rotation around the
PÐC axis.
1
x; 1 ‡ y; 32 z.
Data collection: SMART (Siemens, 1994); cell re®nement:
SMART; data reduction: SHELXTL (Sheldrick, 1994); program(s)
used to solve structure: SHELXTL; program(s) used to re®ne
structure: SHELXL93 (Sheldrick, 1993); molecular graphics:
DIAMOND (Brandenburg, 1996); software used to prepare material
for publication: SHELXTL.
Experimental
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: BR1373). Services for accessing these data are
described at the back of the journal.
The title compound was prepared hydrothermally from a mixture of
gallium oxide, phenylphosphonic acid, hydro¯uoric acid, 1,3-di-
ꢀ
m380 Thierry Loiseau et al.
GaFPO3(C6H5)
Acta Cryst. (2002). C58, m379±m381

metal-organic compounds
Mason, M. R., Matthews, R. M., Mashuta, M. S. & Richardson, J. F. (1996).
Inorg. Chem. 35, 5756±5757.
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Acta Cryst. (2002). C58, m379±m381
Thierry Loiseau et al. GaFPO3(C6H5) m381