The Dimeric Pyramidal Cu2O6(H2O)2Unit – A Structural Invariant of a Homologous Series of Copper-Layered Phosphonates

Article abstract of DOI:10.1002/ejic.201600613

Two new layered copper hybrid materials, namely, the copper thiophene-2,5-diphosphonate [Cu₂(H₂O)₂(O₃P–C₄H₂S–PO₃)] (Pnma; a = 7.525 ?, b = 18.292 ?, c = 7.520 ?) and the copper 3-fluorophenylphosphonate Cu(H₂O)PO₃–C₆H₄F (P2₁/c; a = 14.305 ?, b = 7.550 ?, c = 7.479 ?, β = 92.32°), have been synthesized. These compounds belong to the large homologous Cu(H₂O)PO₃R/[Cu₂(H₂O)₂(O₃P–R–PO₃)] series, the structure of which is dictated by the presence of isolated dimeric pyramidal Cu₂O₆(H₂O)₂units. The role of the Cu/H₂O molar ratio of 1 in the stabilization of such a structure is discussed in connection with the Jahn–Teller effect of the copper cation. The study of the magnetic behavior of polycrystalline samples of the two compounds has revealed antiferromagnetic coupling between the copper ions. The interactions within the dimeric unit were estimated by the Bleaney–Bowers law with the spin Hamiltonian H = –JS_Cu1S_Cu2+ gβHS: J = –6.27 cm^–1for [Cu(H₂O)PO₃]₂C₄H₂S, and J = –6.07 cm^–1for Cu(H₂O)PO₃–C₆H₄F.

Full text of DOI:10.1002/ejic.201600613

DOI: 10.1002/ejic.201600613
Full Paper
Copper Phosphonates
The Dimeric Pyramidal Cu2O6(H2O)2 Unit – A Structural
Invariant of a Homologous Series of Copper-Layered
Phosphonates
Clarisse Bloyet,[a] Mélissa Roger,[b] Jean-Michel Rueff,*[a] Bernard Raveau,[a] Jean-
François Lohier,[c] Guillaume Rogez,[d] and Paul-Alain Jaffrès[b]
Abstract: Two new layered copper hybrid materials, namely, lar ratio of 1 in the stabilization of such a structure is discussed
the copper thiophene-2,5-diphosphonate [Cu2(H2O)2(O3P– in connection with the Jahn–Teller effect of the copper cation.
C4H2S–PO3)] (Pnma; a = 7.525 Å, b = 18.292 Å, c = 7.520 Å) The study of the magnetic behavior of polycrystalline samples
and the copper 3-fluorophenylphosphonate Cu(H2O)PO3–C6H4F of the two compounds has revealed antiferromagnetic coupling
(P21/c; a = 14.305 Å, b = 7.550 Å, c = 7.479 Å, ꢀ = 92.32°), between the copper ions. The interactions within the dimeric
have been synthesized. These compounds belong to the large unit were estimated by the Bleaney–Bowers law with the spin
homologous Cu(H2O)PO3R/[Cu2(H2O)2(O3P–R–PO3)] series, the Hamiltonian H = –JSCu1SCu2 + gꢀHS: J = –6.27 cm–1 for
structure of which is dictated by the presence of isolated di- [Cu(H2O)PO3]2C4H2S, and J = –6.07 cm–1 for Cu(H2O)PO3–C6H4F.
meric pyramidal Cu2O6(H2O)2 units. The role of the Cu/H2O mo-
Introduction
similar inorganic layers built up of dimeric pyramidal
Cu2O6(H2O)2 units. A comparison with previous studies of cop-
per phosphonates demonstrates that these compounds belong
to a large homologous series with quasi similar inorganic layers,
independently of the nature of the organic ligand, provided
that the Cu/H2O molar ratio is equal to 1. The magnetic behav-
ior of the isolated dimeric CuII units is consistent with the
Bleaney–Bowers law.[16]
Transition-metal layered phosphonates[1,2] are an important
class of hybrid inorganic–organic materials that have been in-
vestigated for various applications such as catalysis,[3,4] protonic
conductivity,[5,6] sorption and ionic exchange,[7–9] and magnet-
ism.[10–14] Recently, a layered copper (bromothienyl)phosphon-
ate was shown to exhibit exfoliation properties, which allowed
remarkably enhanced adsorption of PbII ions in aqueous solu-
tion compared with that of the bulk material.[15] In this way,
such hybrid offers a new route to the adsorption of toxic heavy-
metal ions in a more efficient way. The scarcity of this phenom-
enon suggests that the nature of the inorganic nanosheets
plays a crucial role in the generation of these properties and
raises the issue of the influence of the nature of the organic
ligands upon the structure and chemical composition of the
inorganic layers. In the present study, we have synthesized two
new copper layered phosphonates, [Cu2(H2O)2(O3P–C4H2S–
PO3)] and Cu(H2O)PO3–C6H4F, from thiophene-2,5-diphos-
phonic acid (TPdP) and (3-fluorophenyl)phosphonic acid (FPP).
We show that the structures of these hybrids consist of very
Results and Discussion
The organic precursors thiophene-2,5-diphosphonic acid[13]
(Scheme 1, a) and 3-fluorophenylphosphonic acid[17] (Scheme 1,
b) were obtained by phosphonation of bromoaromatic precur-
sors by adapted Tav[18] methods.[19]
[a] CRISMAT, UMR CNRS 6508, ENSICAEN,
Scheme 1. Chemical structures of the organic ligands used for the synthesis
of hybrid materials: (a) TPdP and (b) FPP.
6 boulevard du Maréchal Juin, 14050 Caen Cedex, France
E-mail: jean-michel.rueff@ensicaen.fr
www-crismat.ensicaen.fr
These phosphonic acid precursors were chosen because of
their rigid structures, which result from the direct linkage of the
phosphonic acid groups with a rigid aromatic ring. This rigidity
favors the production of crystalline materials, as we and others
have shown previously.[20] More specifically, the thiophene-2,5-
diphosphonic acid unit was also selected for comparison with
the manganese compound obtained by Rueff et al.[13] The (3-
[b] CEMCA UMR CNRS 6521, Université de Brest, IBSAM,
6 Avenue Victor Le Gorgeu, 29238 Brest, France
[c] Normandie Université, LCMT, UMR CNRS 6507, INC3M, FR 3038, ENSICAEN,
6 boulevard du Maréchal Juin, 14050 Caen Cedex, France
[d] IPCMS, UMR Unistra-CNRS 7504,
23 rue du Loess, BP 43, 67034, Strasbourg Cedex 2, France
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/ejic.201600613.
Eur. J. Inorg. Chem. 0000, 0–0
1
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
fluorophenyl)phosphonic acid unit was chosen for two addi- are occupied by H2O molecules, and the six other apices are
tional reasons. First, this molecule presents one strong inductive shared with six PO3C tetrahedra.
withdrawing fluorine atom that decreases the two pKa values
of the phosphonic acid function.[17] This increase of acidity
should favor the formation of hybrid materials. However, the
impact of this strong electron-withdrawing atom on the topol-
ogy and properties of the final hybrid material was difficult to
anticipate and constitutes one of the reasons of this study. The
second reason for the choice of (3-fluorophenyl)phosphonic
acid is its low symmetry, for instance, compared with (4-fluoro-
phenyl)phosphonic acid. We have shown previously that the
use of low-symmetry organic precursors can produce unex-
pected homochiral hybrid materials.[21]
With these two organic precursors, two new hybrid materials
were obtained as single crystals and polycrystalline pure phases
by hydrothermal synthesis, namely, the copper thiophene-2,5-
diphosphonate [Cu2(H2O)2(O3P–C4H2S–PO3)] and the copper (3-
fluorophenyl)phosphonate Cu(H2O)PO3–C6H4F (the crystallo-
graphic data are presented in Table 1; for the positional and
thermal parameters, see Supporting Information). In spite of
their different symmetries, orthorhombic Pnma and monoclinic
P21/c space groups, respectively (Table 1), these phosphonate-
based hybrids exhibit closely related frameworks. The views of
the structure along a for [Cu2(H2O)2(O3P–C4H2S–PO3)] (Figures 1
and S1-1) and along c for Cu(H2O)PO3–C6H4F (Figures 2 and S2-
Figure 1. Projection of the structure of [Cu2(H2O)2(O3P–C4H2S–PO3)] along the
a axis.
2) show that they both consist of inorganic “CuH2OPO3C” layers
interleaved with “C4H2S” and “C6H4F” organic layers, respec-
tively. In [Cu2(H2O)2(O3P–C4H2S–PO3)], the (010) inorganic layers
are interconnected by the PO3C–C2H2S–CPO3 diphosphonate
groups along b, whereas the (100) inorganic layers in
Cu(H2O)PO3–C6H4F are stacked with double organic PO3C–
C6H4F···H4FC6PO3C layers, which form F···H hydrogen bonds
along a (H···F 2.52–2.98 Å; C–H···F 128.84–136.40°).[22] The struc-
ture of the inorganic layers is practically the same in both phos-
phonates (Figure 3), as expected from the very close values of
the lattice parameters (Table 1). The “CuH2OPO3C” layers are
built up of isolated dimeric “Cu2O6(H2O)2” units. Each unit con-
sists of two edge-sharing CuO4(H2O) pyramids; two free apices
Table 1. Crystallographic data of the “dimeric” copper phosphonates
[Cu2(H2O)2(O3P–C4H2S–PO3)] and Cu(H2O)PO3–C6H4F recorded at 150 K.
Formula
FW
C4H6Cu2O8P2S
403.17
C6H6CuO4PF
255.62
Space group
a [Å]
b [Å]
Pnma
P21/c
Figure 2. Projection of the structure of Cu(H2O)PO3–C6H4F along the c axis.
7.525(3)
18.292(9)
7.520(3)
90, 90, 90
4
1035.11(80)
2.587
4.646
14.3050(6)
7.5504(3)
7.4799(3)
90, 92.3227(19), 90
4
807.23(6)
2.103
2.90
c [Å]
The analysis of the literature on hybrid inorganic–organic
copper phosphonates shows that the TPdP- and FPP-based
hybrids belong to a homologous series of compounds with the
generic formulas Cu(H2O)PO3R for the single phosphonates and
[Cu2(H2O)2(O3P–R–PO3)] for the diphosphonates. In addition to
the two compounds described here, and to the best of our
knowledge, eleven other phosphonates have been found previ-
ously to exhibit this type of formula with a closely related struc-
ture. The crystallographic data of these 13 compounds is listed
in Table 2 and shows that they exhibit inorganic CuH2OPO3C
layers isostructural to that described above, i.e., they are charac-
terized by the same 2D orthogonal lattice of approx. 7.5 × 7.5 Å.
α, ꢀ, γ [°]
Z
V [Å3]
dcalcd. [g/cm3]
μ [mm–1
]
Radiation source λ [Å] Mo-Kα 0.71073
Pattern range 2θ [°]
Reflections
Soft constraints
Rwp
Rp
RF
ꢀ
Mo-Kα 0.71073
5.70–66.34
20434
5.84–73.92
34090
0
0.0603
0.0231
0.0394
1.087
0
0.1746
0.0617
0.0409
1.084
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
2
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Thus, the Cu(H2O)PO3R and [Cu2(H2O)2(O3P–R–PO3)] phos-
phonates form a large homologous series; the structures of
these phosphonates differ by the nature and thickness of the
organic layers, which induces a possible translation of the inor-
ganic layers with respect to each other. Remarkably, the nature
of the organic ligand does not affect the framework of the inor-
ganic layers significantly. The interatomic distances of these
compounds (Table S4-1) show that the geometry of the
CuO4(H2O) pyramid is practically the same whatever the organic
ligand; the four equatorial Cu–O distances range from 1.91 to
1.99 Å, and the apical distance is between 2.31 and 2.40 Å.
The condensed nature of the dimeric Cu2 species with Cu–Cu
distances ranging from 3.04 to 3.15 Å is also not affected by
the organic ligands. As expected, the PO3C tetrahedra are very
similar; the three P–O bonds range from 1.525 to 1.537 Å, and
the P–C bond length is between 1.782 and 1.799 Å.
The cell parameters that characterize the 2D orthogonal lat-
tice (Table 2) are between 7.32 and 7.65 Å and also vary only
slightly; this confirms that the arrangement of the copper
pyramids and PO3C tetrahedra is practically not influenced by
the nature of the organic ligand. The above observations show
that the dimeric pyramidal Cu2O6(H2O)2 unit is a structural inva-
riant of this homologous series and imposes a particularly rigid
geometry of the inorganic layers of these hydrated copper
phosphonates.
Figure 3. Projection of the structure of the inorganic layers in [Cu2(H2O)2(O3P–
C4H2S–PO3)] and Cu(H2O)PO3–C6H4F.
In the single phosphonates Cu(H2O)PO3R, this arrangement of
To the best of our knowledge, only two other phosphonates
the inorganic layers is indeed observed for a large variety of with the Cu(H2O)PO3R formulation exhibit a different structure
organic groups, namely, 3-fluorophenyl (present work), 5-(2- of their inorganic layers. The first exception concerns the 4-(3-
bromothienyl),[15] methyl,[23,24] ethyl,[25] propyl,[26] bro- bromothienyl)phosphonate Cu(H2O)PO3–C4H2BrS.[31] Though it
moethyl,[25] benzyl,[24] 2-carboxyethyl,[25] cyclohexene,[27] and shows some similarity with the 5-(2-bromothienyl)phosphonate
fluorene.[28] The number of [Cu2(H2O)2(O3P–R–PO3)] diphos- in the lattice parameters (Table 2), the structure of its inorganic
phonates is quite limited; in addition to the thiophenyl phase layers is completely different and consists of dimeric units of
R = C4H2S obtained in the present work, only two copper di- edge-sharing CuO6 octahedra. This difference is explained by
phosphonates corresponding to this generic formulation with the fact that the Br atom is at the α position with respect to
the same arrangement of the inorganic layers have been syn- the C atom of the PO3C group; this is in contrast to the 5-(2-
[29,30]
thesized previously for R = C2H4
and p-C6H4.[31]
bromothienyl)phosphonate and leads to a very close proximity
Table 2. Crystallographic data of isostructural inorganic layers made of dimeric copper phosphonates.
Chemical formula
Space group
Cell parameters
α, ꢀ, γ [°]
Reference
this work
a, b, c [Å]
[Cu2(H2O)2PO3–C4H2S–PO3]
Cu(H2O)PO3–C6H4F
ꢀ-Cu(H2O)PO3–C4H2BrS
Cu(H2O)PO3–CH3
Cu(H2O)PO3–CH3
Cu(H2O)PO3–C6H5
Cu(H2O)PO3–CH2–CH3
Cu(H2O)PO3(CH2)2CO2H
Cu(H2O)PO3(CH2)2Br
Cu(H2O)PO3–C3H7
Cu(H2O)PO3–C6H9
Pnma
P21/c
P21/c
P21/c
P21/c
7.525, 18.292, 7.520
14.305, 7.550, 7.4479
15.899, 7.627, 7.344
8.530, 7.602, 7.321
8.495, 7.580, 7.289
7.555, 7.448, 27.982
7.47, 9.94, 7.51
90, 90, 90
90, 92.32, 90
90, 100.07, 90
90, 90.11, 90
90, 90.08, 90
90, 90, 90
90, 93.1, 90
90, 93.3, 90
90, 89.5, 90
90, 97.78, 90
90, 92.12, 90
90, 97.79, 90
90, 116.32, 90
90, 116.32, 90
90, 90.4, 90
this work
[15]
[22]
[24]
[24]
[25]
[25]
[25]
[26]
[27]
[28]
[29]
[30]
[31]
Pbca
unknown
unknown
unknown
P21/a
P21/c
P21/a
P21/c
P21/c
C2/c
7.39, 12.54, 7.55
7.65, 11.26, 7.67
7.437, 7.611, 12.011
14.415, 7.612, 7.529
7.497, 7.547, 22.370
8.076, 7.587, 7.410
8.075, 7.587, 7.399
18.889, 7.622, 7.464
Cu(H2O)PO3–C13H9
[Cu(H2O)(O3P–p-C6H4–CO2H)]
[Cu2(H2O)2(O3P–p-C6H4–CO2H)]
[Cu2(H2O)2(O3P–p-C6H4–CO2H)]
Exceptions
[32]
[21]
α-Cu(H2O)PO3–C4H2BrS
Cu(H2O)PO3–m-C6H4–CO2H
P21/c
P21/m
13.578, 7.587, 7.956
4.841, 32.557, 5.784
90, 99.8, 90
90, 96.02, 90
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
3
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
of the Br atom and the inorganic layer. The second exception
deals with the (carboxyphenyl)phosphonate Cu(H2O)PO3–m-
C6H4–COOH,[21] whose layered structure consists of copper oc-
tahedra that form a pseudo-perovskite 2D lattice. This different
behavior might be due to the experimental conditions, as the
pH was shown to play a crucial role in the selectivity of various
compounds during the synthesis. The review of all the copper
phosphonates shows that the formation of such dimeric pyram-
idal units is unique and only suited to the Cu(H2O)PO3R/
[Cu2(H2O)2(O3P–R–PO3)] series, and the Cu/H2O molar ratio
must be equal to 1. It is indeed remarkable that anhydrous
copper phosphonates such as CuPO3R with R = CH3, C2H5, C6H5,
and CH2C6H5 or other hydrated copper phosphonates such as
Figure 5. Variation of ꢀ (open black circles) and ꢀT (open black squares) with
temperature for Cu(H2O)PO3–C6H4F under 1000 Oe. The red full line corre-
sponds to the best fit of the experimental data to the Bleaney–Bowers law.
Inset: 1/ꢀ versus T and Curie–Weiss fit (performed between 150 and 280 K)
leading C = 0.44 emu K/mol.
Cu3O(CH3PO3)2·2H2O,
Cu2[(O3PC4H8PO3)(H2O)2]·2H2O,
and
Cu2[(O3PC5H10PO3)(H2O)2]·
2.8H2O[33–35] do not exhibit such pyramidal Cu2O8 or
Cu2O6(H2O)2 units.
Conclusions
Two new members of the homologous series of layered copper
phosphonates Cu(H2O)PO3R/[Cu2(H2O)2(O3P–R–PO3)] have been
synthesized. A comparative study of the 13 known members
of the whole series shows that the crystal chemistry of these
compounds is dominated by the formation of unique dimeric
Cu2O6(H2O)2 pyramidal units. The stability of such strongly con-
densed units, in which two pyramids share one edge, is rather
rare. Beyond the fact that the Cu2+ ion favors the pyramidal
coordination owing to the Jahn–Teller effect, the presence of
one water molecule per copper ion apparently plays a crucial
role in the stabilization of such units by decreasing significantly
the negative charge and, consequently, electronic repulsions
around the Cu–Cu dimer relative to those for an eventual Cu2O8
unit. The antiferromagnetic behaviors of both compounds were
fitted by the Bleaney–Bowers law, which led to exchange con-
stants of ca. –6 cm–1 for both compounds.
The evolution of the magnetic susceptibility (ꢀ) and the
product of the susceptibility and temperature (ꢀT) versus tem-
perature for [Cu2(H2O)2(O3P–C4H2S–PO3)] and Cu(H2O)PO3–
C6H4F are presented in Figures 4 and 5, respectively. For the
TPdP and FPP hybrids, the susceptibilities increase continuously
from 0.00162 and 0.00159 emu/mol, respectively, at 280 K to
reach maximum values of 0.03995 and 0.03994 emu/mol at 5 K.
Below this temperature,
ꢀ decreases to 0.02568 and
0.02453 emu/mol at 2 K for [Cu2(H2O)2(O3P–C4H2S–PO3)] and
Cu(H2O)PO3–C6H4F, respectively. These ꢀ curves are typical of
antiferromagnetic behavior. For ꢀT, the curves present plateaus
from 280–70 K with corresponding ꢀT values of 0.45027 and
0.4377 emu K/mol for [Cu2(H2O)2(O3P–C4H2S–PO3)] and
Cu(H2O)PO3–C6H4F, respectively. Below 70 K, ꢀT decreases to
reach values of 0.05136 and 0.04906 emu K/mol at 2 K. The ꢀ =
f(T) and ꢀT = f(T) curves were fit simultaneously with the
Bleaney–Bowers law[16] with the spin Hamiltonian
–JSCu1SCu2 + gꢀHS; all of the parameters have their usual mean-
ing, and the spin operator is defined as S = SCu1 + SCu2
H =
Experimental Section
.
General: Thiophene-2,5-diphosphonic acid was synthesized by fol-
lowing the reported procedures.[13]
All compounds were characterized by NMR spectroscopy [Bruker
AC 300, Avance DRX 400, or Avance DRX 500 spectrometers were
used to record the NMR spectroscopic data (1H: 500, 400, or
300 MHz; 31P: 162 or 121.5 MHz; 13C: 125.8 or 75.5 MHz)]. The chem-
ical shifts are in ppm. Coupling constants J are given in Hz. The
following abbreviations are used: s singlet, d doublet, t triplet, q
quadruplet, qt quintuplet, m multiplet, and dt doublet of triplets.
The ESI mass spectra were recorded with a Shimadzu LCMS-2020
instrument with samples in MeOH. The IR spectra of the organic
compounds were recorded with a Nicolet Nexus FTIR spectrometer
working in the transmittance mode in the ν = 200–4000 cm–1 range.
Figure 4. Variation of ꢀ (open black circles) and ꢀT (open black squares) with
temperature for [Cu2(H2O)2(O3P–C4H2S–PO3)] under 1000 Oe. The red full line
corresponds to the best fit of the experimental data to the Bleaney–Bowers
law. Inset: 1/ꢀ versus T and Curie–Weiss fit (performed between 150 and
280 K) leading to C = 0.45 emu K/mol.
˜
3-Bromofluorobenzene was purchased from TCI, and 2,5-dibromo-
thiophene was purchased from Acros and used without further pu-
rification. For both hybrid materials, inorganic reagents were pur-
chased from Sigma–Aldrich.
The thermogravimetric analysis (TGA) of polycrystalline samples
was performed with a SETARAM TAG 92 apparatus under a nitrogen
atmosphere for [Cu2(H2O)2(O3P–C4H2S–PO3)] and an air atmosphere
for Cu(H2O)PO3–C6H4F at a heating rate of 3 °C/min from room
temperature to 1000 °C. The scanning electron microscopy (SEM)
characterization was performed with a Carl Zeiss SUPRA 55 instru-
For the TPdP hybrid, the fit leads to J = –6.27(4) cm–1, g =
2.21(1); and that for the FPP hybrid leads to J = –6.07(3) cm–1,
g = 2.18(1). Note that the interdimer exchange coupling was
neglected on the basis of our previous results for CuII n-alkyl-
phosphonates.[26]
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
4
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
ment with raw samples with gold metallization. The magnetic sus- data for this paper. These data can be obtained free of charge from
ceptibilities were recorded versus temperature with a Quantum De-
sign superconducting quantum interference device (SQUID) magne-
tometer operating in the temperature range 2–300 K under zero-
field cooling (ZFC) and field cooling (FC) conditions with an applied
magnetic field of 0.1 T. The data were corrected for the sample
holder, and diamagnetism was estimated from Pascal constants.
The Cambridge Crystallographic Data Centre.
The homogeneity of both phases was confirmed by powder X-ray
diffraction (Supporting Information).
[Cu2(H2O)2(O3P–C4H2S–PO3)]:
A
mixture of Cu(NO3)2·3H2O
(0.409 mmol, 0.0990 g, 2 equiv.) and tetraethyl thiophene-2,5-di-
phosphonate (0.205 mmol, 0.0502 g, 1 equiv.) was placed in a 50 mL
polytetrafluoroethylene (PTFE) liner (Scheme 1, a). To these rea-
gents, urea (0.409 mmol, 0.0247 g, 1 equiv.) was added, and then
all precursors were dissolved in distilled water (10 mL). The liner
was transferred into a Berghof DAB-2 pressure digestion vessel, and
the mixture was heated from room temperature to 140 °C over 25 h,
kept at 140 °C for 35 h, and a cooled to room temperature over
25 h. The final product, obtained as green platelets, was collected
by filtration, washed with distilled water, rinsed with ethanol, and
then dried in air. Cu2C4H6P2O8S (403.17): calcd. C 11.92, H 1.50;
found C 11.65, H 1.78.
Diethyl 3-Fluorophenylphosphonate: To a solution of NiBr2
(1.87 g, 8.57 mmol; 6 %) suspended in mesitylene (25 mL) and 3-
bromofluorobenzene (25 g, 142.86 mmol) under nitrogen at 165 °C
for activation was added triethyl phosphite (27 mL, 157.14 mmol,
1.1 equiv.) by slow and discontinuous dropwise addition (this addi-
tion must be achieved with care). At the end of the addition, the
reaction mixture was stirred at 165 °C overnight. After the reaction
mixture cooled, the excess triethyl phosphite and mesitylene were
removed by distillation under reduced pressure (ca. 0.1 mbar). The
resulting mixture was dissolved in dichloromethane (250 mL), and
water (250 mL) was added. The heterogeneous solution was stirred
at room temperature for 6 h. The two layers were separated, and
the organic layer was washed with water (250 mL). The aqueous
phase was extracted with dichloromethane (2 × 250 mL). The or-
ganic layers were combined, dried with MgSO4, and evaporated
under reduced pressure to yield a clear oil. The crude product was
purified by silica gel column chromatography (CH2Cl2) to yield a
Cu(H2O)PO3–C6H4F: Cu(H2O)PO3–C6H4F (Scheme 1, b) was ob-
tained by the same process as described previously from
Cu(NO3)2·3H2O (0.0687 g, 0.284 mmol), (3-fluorophenyl)phosphonic
acid (0.0501 g, 0.284 mmol), and urea (NH2)2CO (0.017 g,
0.203 mmol) in distilled water (15 mL). The heating cycle was as
follows: room temperature to 140 °C over 20 h, 30 h at 140 °C, and
room temperature over 20 h. CuC6H6PO4F (255.62): calcd. C 28.19
H 2.37; found C 27.96, H 2.79.
1
clear oil (24.0 g, 72 %). Rf (CH2Cl2/MeOH: 98:2): 0.3. H NMR (CDCl3,
500 MHz): δ = 1.33 (t, 3J = 7.5 Hz, 6 H, CH3), 4.05–4.21 (m, 4 H, CH2),
3
4
7.19–7.25 (td, J = 9.0 Hz, J = 2.5 Hz, 1 H, HAr4), 7.39–7.52 (m, 2 H,
Ar2+5), 7.54–7.56 (ddm, J = 7.5, 12.9 Hz, 1 H, HAr6) ppm. 31P{1H}
NMR (CDCl3, 162 MHz): δ = 17.1 (d, 4JP, F = 8.8 Hz) ppm. 13C{1H} NMR
Thermogravimetric Analysis: The TGA curves for polycrystalline
samples of [Cu2(H2O)2(O3P–C4H2S–PO3)] and Cu(H2O)PO3–C6H4F are
presented in Figure 6. Both compounds exhibited thermal stability
from room temperature to 140 °C, in agreement with the presence
of a first plateau in the curves. The first weight losses, from 140–
200 °C, indicate the departure of the water molecules linked to the
Cu centers and correspond to two and one H2O molecule per for-
mula for the TPdP and FPP hybrids, respectively. For the TPdP
hybrid, the experimental value of 8.40 % is in good agreement with
the calculated value of 8.96 % expected for the departure of two
water molecules, and the loss of 6.77 % for the FPP hybrid corre-
sponds to a theoretical value of 7.05 % for the departure of one
water molecule. From 200–300 °C, a second plateau provides evi-
dence of the thermal stability of the dehydrated compounds [Cu-
PO3]2–C4H2S and CuPO3–C6H4F. Beyond 300 °C, the last weight
losses can be attributed to the decomposition of the organic moie-
ties and to the transformation of the dehydrated compounds into
Cu2P2O7 at 830 °C for [Cu2(H2O)2(O3P–C4H2S–PO3)] and at 560 °C
for Cu(H2O)PO3–C6H4F. The copper pyrophosphate was identified
by powder X-ray diffraction with the TGA residues.
H
3
2
(CDCl3, 125 MHz): δ = 16.2 (d, JP, C = 6.4 Hz, CH3), 62.3 (d, JC,P
=
3
3
5.4 Hz, CH2), 118.5 (dd, J = 10.4 Hz, J = 10.4 Hz, CHAr2), 119.5 (dd,
2JC,F = 21.1 Hz, 4JC,P = 2.5 Hz, CHAr4), 127.4 (dd, 2JC,P = 9.0 Hz, 4JC,F
=
=
=
3
1
2.7 Hz, CHAr6), 130.4 (dd, J = 7.4, 7.3 Hz, CHAr5), 131.0 (dd, JC,P
3
1
3
189.0 Hz, JC,F = 6.0 Hz, Cq1), 162.3 (dd, JC,F = 249.0 Hz, JC,P
21.4 Hz, Cq3) ppm. 19F {1H} NMR (CDCl3, 282 MHz): δ = –112.1 (d,
4JF,P = 8.8 Hz) ppm. MS: m/z = 233.00 [M + H]+, 265.00 [M + Na]+,
465.10 [2M + H]+, 488.15 [2M + H + Na]+. IR: ν = 961 (C–O), 1015
˜
(P–O), 1224 (P=O), 1426 (C–F), 2984 (C–H) cm–1
.
3-Fluorophenylphosphonic Acid: Diethyl 3-fluorophenylphos-
phonate (20 g, 86.1 mmol) was dissolved in concentrated hydro-
chloric acid (125 mL). The solution was stirred under reflux over-
night. The HCl and water were evaporated under reduced pressure
to give a white powder (14.0 g, 93 %). 1H NMR (D2O, 400 MHz): δ =
7.28 (t, 3J = 8.4 Hz, 1 H, HAr), 7.42–7.56 (m, 3 H, HAr) ppm. 31P{1H}
4
NMR (D2O, 162 MHz): δ = 14.0 (d, JP, F = 7.9 Hz) ppm. 13C{1H} NMR
3
(D2O, 125 MHz): δ = 119.7 (dd, J = 10.9, 10.9 Hz, CHAr2), 121.4 (dd,
2JC,F = 21.2 Hz, 4JC,P = 2.6 Hz, CHAr4), 129.0 (dd, 2JC,P = 9.5 Hz, 4JC,F
2.7 Hz, CHAr6), 133.5 (dd, J = 7.8, 7.8 Hz, CHAr5), 137.0 (dd, JC,P
=
=
=
=
3
1
3
1
3
181.7 Hz, JC,F = 6.1 Hz, Cq1), 164.9 (dd, JC,F = 246.2 Hz, JC,P
21.0 Hz, Cq3) ppm. 19F{1H} NMR (D2O, 282 MHz): δ = –113.1 (d, 4JP, F
8.5 Hz) ppm. MS: m/z = 177.00 [M + H]+, 218.05 [M + H + CH3CN]+,
259.00 [M + H + 2CH3CN]+, 353.00 [2M + H]+, 394.00 [2M + H +
CH CN]+, 529.05 [3M + H]+. IR: ν = 1001 (P–O), 1231 (P=O), 1425
˜
3
(C–F), 2000–3000 (O–H) cm–1. UV/Vis (MeOH): λmax = 216 nm.
Single-Crystal X-ray Diffraction: For both compounds, suitable
single crystals were selected, and X-ray diffraction experiments were
performed at 150 K with a Bruker-Nonius Kappa CCD area detector
diffractometer with graphite-monochromated Mo-Kα radiation (λ =
0.71073 Å). SHELXL-2014 was used to refine the structure.
Figure 6. TGA curves of [Cu2(H2O)2(O3P–C4H2S–PO3)] (full line) and
Cu(H2O)PO3–C6H4F (dashed line) recorded under nitrogen and air, respec-
tively.
CCDC 1478143 {for [Cu2(H2O)2(O3P–C4H2S–PO3)]} and 1478142 [for
Cu(H2O)PO3–C6H4F] contain the supplementary crystallographic
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
5
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
[12] S.-S. Bao, Y. Liao, Y.-H. Su, X. Liang, F.-C. Hu, Z. Sun, L.-M. Zheng, S. Wei,
R. Alberto, Y.-Z. Li, J. Ma, Angew. Chem. Int. Ed. 2011, 50, 5504–5508;
Angew. Chem. 2011, 123, 5618.
[13] J.-M. Rueff, O. Perez, A. Pautrat, N. Barrier, G. B. Hix, S. Hernot, H. Couthon-
Gourvès, P.-A. Jaffrès, Inorg. Chem. 2012, 51, 10251–10261.
[14] J.-M. Rueff, O. Perez, C. Simon, H. Couthon-Gourvès, C. Lorilleux, P.-A.
Jaffrès, Cryst. Growth Des. 2009, 9, 4262–4268.
Scanning Electron Microscopy: The homogeneous batches of
[Cu2(H2O)2(O3P–C4H2S–PO3)] were identified as platelets with an av-
erage length of 34.3 μm, width of 25.7 μm, and an average thick-
ness of 2 μm (see Supporting Information).
Cu(PO3–C6H4F)·H2O also consists of platelets with lengths of 85.7–
108.6 μm, widths of 51.4–100 μm, and an average thickness of
1.6 μm (see Supporting Information).
[15] W.-X. Nie, S.-S. Bao, D. Zeng, L.-R. Guo, L.-M. Zheng, Chem. Commun.
2014, 50, 10622–10625.
[16] B. Bleaney, K. D. Bowers, Proc. R. Soc. London, Ser. A 1952, 214, 451–465.
[17] G. Keglevich, A. Grün, A. Bölcskei, L. Drahos, M. Kraszni, G. T. Balogh,
Heteroat. Chem. 2012, 23, 574–582.
Acknowledgments
[18] P. Tavs, Chem. Ber. 1970, 103, 2428–2436.
The authors thank the Agence Nationale de la Recherche [con-
tract no. ANR-14-CE07-0004-01 (HYMN)] for financial support.
The authors also express their grateful acknowledgment for
technical support to Sylvie Collin and Fabien Veillon from the
CRISMAT laboratory and to Sylvie Hernot form the CEMCA labo-
ratory and the Service de RMN, UFR Sciences et Techniques,
Université de Bretagne Occidentale, Brest.
[19] J.-M. Rueff, V. Caignaert, S. Chausson, A. Leclaire, C. Simon, O. Perez, L.
le Pluart, P.-A. Jaffrès, Eur. J. Inorg. Chem. 2008, 4117–4125.
[20] J. M. Rueff, G. B. Hix, P. A. Jaffrès, in: Tailored Organic–Inorganic Materials
(Eds.: Jorge L. Colón Ernesto Brunet, A. Clearfield), 1st ed., John Wiley &
Sons, Hoboken, 2015, chapter 9, p. 341–393.
[21] J.-M. Rueff, V. Caignaert, A. Leclaire, C. Simon, J.-P. Haelters, P.-A. Jaffrès,
CrystEngComm 2009, 11, 556.
[22] V. R. Thalladi, H.-C. Weiss, D. Bläser, R. Boese, A. Nangia, G. R. Desiraju, J.
Am. Chem. Soc. 1998, 120, 8702–8710.
[23] C. Houttemane, J. C. Boivin, D. J. Thomas, M. Wozniak, G. Nowogrocki,
Keywords: Hybrid materials · Layered compounds ·
Hydrothermal synthesis · Copper · Phosphonates · Dimeric
units
Acta Crystallogr., Sect. B 1979, 35, 2033–2037.
[24] Y. Zhang, A. Clearfield, Inorg. Chem. 1992, 31, 2821–2826.
[25] S. Drumel, P. Janvier, P. Barboux, M. Bujoli-Doeuff, B. Bujoli, Inorg. Chem.
1995, 34, 148–156.
[26] S. Chausson, J.-M. Rueff, M. B. Lepetit, O. Perez, R. Retoux, C. Simon, L.
Le Pluart, P.-A. Jaffrès, Eur. J. Inorg. Chem. 2012, 2193–2202.
[27] H.-C. Yao, Y.-Z. Li, S. Gao, Y. Song, L.-M. Zheng, X.-Q. Xin, J. Solid State
Chem. 2004, 177, 4557–4563.
[28] N. Hugot, M. Roger, J.-M. Rueff, J. Cardin, O. Perez, V. Caignaert, B. Raveau,
G. Rogez, P.-A. Jaffrès, Eur. J. Inorg. Chem. 2016, 266–271.
[29] D. M. Poojary, B. Zhang, A. Clearfield, J. Am. Chem. Soc. 1997, 119, 12550–
12559.
[30] E. Burkholder, V. O. Golub, C. J. O'Connor, J. Zubieta, Inorg. Chim. Acta
2002, 340, 127–132.
[31] D. M. Poojary, B. Zhang, P. Bellinghausen, A. Clearfield, Inorg. Chem. 1996,
35, 4942–4949.
[1] A. Clearfield, K. D. Demadis, Metal Phosphonate Chemistry: From Synthesis
to Application, RSC Publishing, Cambridge, UK, 2012.
[2] E. Brunet, J. L. Colon, A. Clearfield (Eds.), Tailored Organic–Inorganic Mate-
rials, John Wiley & Sons, Hoboken, 2015.
[3] O. R. Evans, H. L. Ngo, W. Lin, J. Am. Chem. Soc. 2001, 123, 10395–10396.
[4] L. Ma, C. Abney, W. Lin, Chem. Soc. Rev. 2009, 38, 1248–1256.
[5] J. M. Taylor, R. K. Mah, I. L. Moudrakovski, C. I. Ratcliffe, R. Vaidhyanathan,
G. K. H. Shimizu, J. Am. Chem. Soc. 2010, 132, 14055–14057.
[6] X. Liang, F. Zhang, W. Feng, X. Zou, C. Zhao, H. Na, C. Liu, F. Sun, G. Zhu,
Chem. Sci. 2013, 4, 983–992.
[7] P. O. Adelani, T. E. Albrecht-Schmitt, Angew. Chem. Int. Ed. 2010, 49, 8909–
8911; Angew. Chem. 2010, 122, 9093.
[32] L. R. Guo, F. Zhu, Y. Chen, Y.-Z. Li, L.-M. Zheng, Dalton Trans. 2009, 8548–
8554.
[33] J. Le Bideau, C. Payen, P. Palvadeau, B. Bujoli, Inorg. Chem. 1994, 33,
4885–4890.
[8] M. Plabst, L. B. McCusker, T. Bein, J. Am. Chem. Soc. 2009, 131, 18112–
18118.
[34] D. I. Arnold, X. Ouyang, A. Clearfield, Chem. Mater. 2002, 14, 2020–2027.
[35] J. Le Bideau, B. Bujoli, A. Jouanneaux, C. Payen, P. Palvadeau, J. Rouxel,
Inorg. Chem. 1993, 32, 4617–4620.
[9] M. T. Wharmby, J. P. S. Mowat, S. P. Thompson, P. A. Wright, J. Am. Chem.
Soc. 2011, 133, 1266–1269.
[10] P.-F. Wang, Y. Duan, J. M. Clemente-Juan, Y. Song, K. Qian, S. Gao, L.-M.
Zheng, Chem. Eur. J. 2011, 17, 3579–3583.
[11] Y.-Z. Zheng, M. Evangelisti, F. Tuna, R. E. P. Winpenny, J. Am. Chem. Soc.
2012, 134, 1057–1065.
Received: May 23, 2016
Published Online: ■
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
6
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Copper Phosphonates
The layered copper phosphonates
Cu(H2O)PO3R and [Cu2(H2O)2(O3P–R–
PO3)] form a large structural family
characterized by the presence of
C. Bloyet, M. Roger, J.-M. Rueff,*
B. Raveau, J.-F. Lohier, G. Rogez,
P.-A. Jaffrès ........................................... 1–7
condensed
dimeric
pyramidal
The Dimeric Pyramidal Cu2O6(H2O)2
Unit – A Structural Invariant of a Ho-
mologous Series of Copper-Layered
Phosphonates
Cu2O6(H2O)2 units. Two new members
of this family with R = C6H4F and
C4H4S are synthesized. These hybrids
exhibit antiferromagnetic interactions
between the copper ions that obey
the Bleaney–Bowers law.
DOI: 10.1002/ejic.201600613
Eur. J. Inorg. Chem. 0000, 0–0
www.eurjic.org
7
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim