Enantiomerically pure zinc phosphonates based on mixed phosphonic acid - Phosphine oxide chiral building blocks

Article abstract of DOI:10.1039/b007868i

The coordination chemistry of enantiomerically pure phosphonic acids H₂O₃PCH₂P(O)(C₆H₅)(R) [R = CH₃ and C₂H₅] with zinc is described. The structures of two new optical

Full text of DOI:10.1039/b007868i

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Enantiomerically pure zinc phosphonates based on mixed phosphonic
acid–phosphine oxide chiral building blocks
Florence Fredoueil,a Michel Evain,b Dominique Massiot,c Martine Bujoli-Doeuffb and
Bruno Bujoli*a
aLaboratoire de Synthe`se Organique, UMR CNRS 6513, 2 Rue de la Houssinie`re, BP92208
44322 Nantes Cedex 03, France
bInstitut des Mate´riaux Jean Rouxel, UMR CNRS 6502, 2 Rue de la Houssinie`re, BP92208
44322 Nantes Cedex 03, France
cCRMHT, UPR CNRS 4212, 1D Avenue de la Recherche Scientifique, 45071 Orle´ans Cedex
02, France. E-mail: bujoli@chimie.univ-nantes.fr
Received 28th September 2000, Accepted 19th January 2001
First published as an Advance Article on the web 27th February 2001
The coordination chemistry of enantiomerically pure phosphonic acids H2O3PCH2P(O)(C6H5)(R) [R~CH3 and
C2H5] with zinc is described. The structures of two new optically active layered zinc phosphonates (R)-a-
Zn(O3PCH2P(O)(C6H5)(CH3)) and (R)-a-Zn(O3PCH2P(O)(C6H5)(C2H5))?H2O were determined, in which the
phosphine oxide is coordinated to zinc. This coordination can be avoided when the synthesis is performed in a
slightly acidic medium, as evidenced by the structure of (R)-b-Zn(O3PCH2P(O)(C6H5)(CH3))?H2O.
modified version of the procedure described by Collignon et
Introduction
al.8 The key reaction is the condensation of the lithiated anion
of diethyl methylphosphonate with the corresponding alkyl-
phenylphosphinyl chloride (Scheme 1). The optical resolution
of 1 and 2 was performed using quinine or quinidine to give 1-
(R) in 81% yield (based on one of the enantiomers), 2-(R) in
84% yield and 2-(S) in 76% yield. These compounds were then
reacted with zinc nitrate in water, in Teflon sealed autoclaves at
110 ‡C under neutral-pH conditions, to yield enantiomerically
pure layered phosphonates having similar structures: (R or S)-
a-Zn(O3PCH2P(O)(R)(C6H5))?H2O [R~CH3: a-Zn1-(R) (85%
yield); R~C2H5: a-Zn2-(R) (87% yield) and a-Zn2-(S) (78%
yield)]. The structure of a-Zn2-(R) was solved by single crystal
X-ray diffraction showing a metal/PO3 arrangement within the
slabs similar to that observed in the previously reported a-Zn1-
(R)5 (ab plane; Fig. 1); the zinc atoms are tetrahedrally
coordinated with three oxygen atoms from the phosphonate
groups and one oxygen atom from the phosphine oxide moiety.
In each layer, the zinc atoms are arranged in 12-membered
rings, constructed by corner-sharing of alternating ZnO4 and
PO3C tetrahedra. The phenyl groups are oriented toward the
The field of metal phosphonates has grown very large,1 with
various examples of applications,2 among which catalysis has
retained a particular interest for our group.3 Moreover, for a
given metal, we and others have shown that the structure and
dimensionality of these supramolecular assemblies are strongly
dependent on the organic precursor, according to its size and
the number and nature of its functional groups.4 In a recent
communication, we described the first enantiomerically pure
phosphonate, showing that even the optical purity of the
phosphonic acid precursor can induce changes in the metal/PO3
coordination mode in the resulting phosphonates.5 In this
paper, we fully report the coordination chemistry of phospho-
nic acids functionalized by enantiomerically pure phosphine
oxide groups [H2O3PCH2P(O)(R)(C6H5); R~CH3 (1-(R)) or
C2H5 (2-(R) and 2-(S))] and show how the inorganic frame-
work adapts itself to the main features of the organic units. The
use of phosphine oxides as crystallization aids is well known
and stems from their ability to form strong hydrogen bonds
with proton donor organic substrates.6 Thus, the preparation
of materials incorporating this kind of functional block could
potentially lead to liquid chromatography chiral stationary
phases7 for the resolution of enantiomers of chiral alcohols,
amines or a-amino acids. In this context, the coordination of
the phosphine oxide must be avoided, and we were interested to
know if this was possible in the case of metal phosphonates.
˚
interlayer space, with a basal spacing (c/2~12.65 A [R~CH3]
˚
˚
and c~13.30 A [R~C2H5]) shorter than the 15–16 A value
generally observed for layered metal phenylphosphonates. This
is due to a close-packing of the sheets caused by an unusual
interdigitation of the aromatic rings from neighboring slabs
(Fig. 2), with probable p–p interactions that contribute to a
good stabilization of this two-dimensional arrangement. The
lattice water molecules are present between the layers, weakly
hydrogen-bonded to phosphonate oxygen atoms, thus explain-
ing the low temperature (55 ‡C) at which the dehydration takes
place. The configuration of the chiral phosphorus atom of the
Results
The phosphonic acid H2O3PCH2P(O)(R)(C6H5) racemates (1
[R~CH3]–2 [R~C2H5]) were prepared according to
a
Scheme 1
1106
J. Mater. Chem., 2001, 11, 1106–1110
This journal is # The Royal Society of Chemistry 2001
DOI: 10.1039/b007868i

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Fig. 1 Schematic representation of a (R)-a-Zn(O3PCH2P(O)(R)(C6H5))?H2O [R~CH3 (according to ref. 5; left), R~C2H5 (right)] layer viewed
down the c axis.
phosphine oxide group was unambiguously determined to be R
(see Fig. 2) by refining the inversion twin ratio, showing that no
racemization occurred during the self-assembly of the phos-
phonate network. In addition, the spectroscopic data of
compounds a-Zn2-(R) and a-Zn2-(S) were found to be
identical (FTIR spectra, 31P CP-MAS NMR spectra, X-ray
powder diffraction patterns, TGA curves) and the values of the
specific rotation measured for the two compounds were found
to be the same with opposite signs ([a]D20~¡5 (c~1 in 1 M
HCl)), thus giving evidence that the two compounds are
enantiomers.
It is worthwhile noting that a triclinic space group was found
for compound a-Zn2-(R) whereas a-Zn1-(R) is an orthorhom-
bic phase; this is probably due to the replacement of the methyl
substituent bound to the phosphine oxide by an ethyl chain.
This lower symmetry results in the presence of two sets of
positions for the O3PCH2P(O)(C2H5)(C6H5) blocks in the unit
cell, in agreement with solid state 31P CP-MAS NMR
measurements showing four signals for this phase: 7.9 and
10.6 ppm (PO3), 57.2 and 57.6 (PO). The two P–C–P blocks
were easily indexed, using rotational resonance conditions.
These experiments have been developed to recover homo-
nuclear dipolar coupling constants from high-resolution NMR
experiments conducted with MAS, in systems containing
isolated spin pairs. The line shape of the 31P signals changes
if the spinning speed is adjusted such that an integer multiple of
the spinning speed matches the chemical shift difference
between the two coupled phosphorus nuclei (homonuclear
coupling due to the short distance between the P atoms in the
P–C–P linkage).9 Thus two signal pairs were identified: (57.6,
7.9 ppm) and (57.2, 10.6 ppm) (Fig. 3). Moreover, the dehy-
dration of the (R or S)-a-Zn(O3PCH2P(O)(R)(C6H5))?H2O
series was found to be non-reversible; the structure of the
anhydrous form of a-Zn1-(R), (R)-a-Zn(O3PCH2P(O)(CH3)-
(C6H5)), solved by single crystal X-ray diffraction, reveals a
˚
decrease of the interlayer distance (close to 2 A), consistent
Fig. 2 Schematic representation of the layered arrangement of (R)-a-
Zn(O3PCH2P(O)(C2H5)(C6H5))?H2O as seen perpendicular to the a
˚
axis. Selected interatomic distances (A): Zn–O: 1.891(7), 1.898(7),
Fig. 3 Experimental 31P MAS NMR spectra of (R)-a-Zn(O3PCH2-
P(O)(C2H5)(C6H5))?H2O, spinning at 7.6 kHz (a) and 8.1 kHz (b),
under the condition of rotational resonance (n~1) for the signal pairs:
[57.2 and 10.6 ppm] (a) and [57.6 and 7.9 ppm] (b). The asterisks denote
spinning side bands.
˚
1.925(7), 1.979(7) A for Zn(1) and 1.904(7), 1.906(6), 1.928(8),
˚
1.998(7) A for Zn(2); (phosphonate group) P–O: 1.510(7), 1.516(7),
˚
1.521(8) A for P(1) and 1.516(7), 1.518(7), 1.508(8) A for P(2);
˚
˚
˚
(phosphine oxide group) P–O: 1.514(8) A for P(3) and 1.531(8) A for
P(4).
J. Mater. Chem., 2001, 11, 1106–1110
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Fig. 4 Schematic representation of the layered arrangement of (R)-a-
Zn(O3PCH2P(O)(CH3)(C6H5)) as seen perpendicular to the a axis.
with a markedly higher interdigitation of the phenyl rings
(Fig. 4). This leads to a very efficient space filling arrangement,
with strong interactions between the aromatic rings that
probably tightly hold the layers together. This effect is
responsible for a stabilization of the dehydrated form of a-
Zn1-(R), that consequently does not absorb water. As
expected, the removal of the non-coordinated water molecule
does not modify the metal/PO3 arrangement within the layers
(Fig. 5).
Fig. 6 Schematic representation of the layered arrangement of (R)-b-
Zn(O3PCH2P(O)(CH3)(C6H5))?H2O as seen perpendicular to the b
axis.
We have previously shown that the coordinating properties
of functional groups (CO2H, NH2) present on the phosphonic
acid precursor are sensitive to the pH value of the reaction
medium: i.e., when the pH is acidic enough, the coordination of
these groups to the metal atoms can be avoided.10 We have
checked that this was also true in the case of precursor 1-(R)
since (R)-b-Zn(O3PCH2P(O)(CH3)(C6H5))?H2O [b-Zn1-(R)]
was isolated when the synthesis was performed at pH 4. The
structure of this compound was solved by single-crystal X-ray
diffraction and confirms that the phosphine oxide is not
bonded to zinc and is expanding towards the interlayer space
(Fig. 6). The metal atoms within the sheets (ab-plane) are
octahedrally coordinated by four phosphonate oxygen atoms
(leading to a (112) connectivity for the PO3 groups) and two
water molecules that are bridging two different zinc atoms. The
structure can thus be described as infinite chains of edge-
Fig. 7 Schematic
P(O)(CH3)(C6H5))?H2O layer as seen perpendicular to the c axis.
representation
of
a
(R)-b-Zn(O3PCH2-
˚
Selected interatomic distances (A): Zn–O: 2.025(4) [62], 2.051(6) [62],
˚
2.229(6) [62] A for Zn(1) and 2.036(4) [62], 2.074(6) [62], 2.236(6)
˚
[62] A for Zn(2); (phosphonate group) P–O: 1.511(6), 1.518(7),
˚
1.544(3) A; (phosphine oxide group) P–O: 1.499(4) A.
˚
sharing ZnO6 octahedra running parallel to the b-axis,
connected together by the PO3 moieties to form the 2D
inorganic network (Fig. 7). The configuration of the chiral
phosphorus center was (R). As the water molecule is
coordinated to zinc, the water loss is observed at a higher
temperature (150 ‡C) than that observed for a-Zn1-(R). While
the P(O)(CH3)(C6H5) group is not coordinated, it should be
noted however that the metal/PO3 arrangement does not
correspond to that usually observed in MII(RPO3)?H2O alkyl-
or arylphosphonates;11 this is due to the size of the phosphine
oxide moiety that cannot fit this latter structural model, in
which the PO3R groups are closely packed. This gives again
evidence of the structure directing role of the organic moiety in
the coordination chemistry of phosphonic acids. In addition,
these results clearly demonstrate that the two optical antipodes
of a chiral metal phosphonate can be selectively prepared.
However, if the synthesis is performed at higher temperature
Fig. 5 Schematic representation of a (R)-a-Zn(O3PCH2P(O)(CH3)-
(C6H5)) layer viewed down the c axis. Selected interatomic distances
˚
(A): Zn–O: 1.892(2), 1.914(2), 1.939(2), 2.007(2) A; (phosphonate
˚
˚
group) P–O: 1.504(2), 1.513(2), 1.517(2) A; (phosphine oxide group)
˚
P–O: 1.513(2) A.
1108 J. Mater. Chem., 2001, 11, 1106–1110

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(180 ‡C), a racemization of the phosphonic acid occurs, leading
to racemic phosphonates identical to that obtained when the
preparation is carried out using the racemic phosphonic acid as
starting material.4
Crystal data. (R)-a-Zn(O3PCH2P(O)(CH3)(C6H5)), ortho-
˚
rhombic, P212121; a~5.5038(3), b~8.9927(6), c~21.187(1) A,
21
˚
V~1048.6(1) A, Z~4; M~297.50; m~26.4 cm
.
Structure determination of b-Zn1-(R)
Data collection was carried out as above (but at 120 K), with a
single crystal approximately 0.5260.1160.008 mm in size. C2
was found to be the correct space group. At the last stage of the
refinement (same conditions as above), a secondary extinction
coefficient17 was introduced and the residue factor smoothly
converged with R/Rw~0.0356/0.0632 for 1851 independent
reflections with I/s(I)w2 [from 2553 collected reflections:
R(int)all~0.074] and 112 parameters. A disorder in the position
of the phenyl rings was observed, according to two main
orientations tilted one to another by 90‡. The occupation ratio
was refined to 0.51 and 0.49 for the two sets of aromatic carbon
atoms respectively. The absolute configuration was unambigu-
ously determined by refining the inversion twin fraction
t(inv)~20.05(3), which was subsequently fixed to 0.
Experimental
Materials and methods
All starting materials were purchased from Aldrich Chemical
Co. and were used as received. The chemical analyses were
performed by the C.N.R.S. Analysis Laboratory (Vernaison).
FTIR spectra were obtained on a Bruker Vector22 FT-IR
spectrometer with the usual KBr pellet technique. A Perkin-
Elmer TGS2 thermogravimetric analyzer was used to obtain
TGA thermograms, that were run in an air atmosphere from
room temperature to 250 ‡C at a scan rate of 5 ‡C min21. The
1H and 31P NMR spectra recorded in solution were taken on an
AC 200 Bruker spectrometer, with tetramethylsilane (tri-
methylphosphite) as reference. Solid state 31P NMR spectra
were acquired on a Bruker DSX400 spectrometer operating at
9.4 T, using CP-MAS {1H}–31P excitation, as previously
described,12 with a typical contact time of 1.5 ms and 1 s
recycle time. Spectra were simulated using a modified version
of the Bruker Winfit program.13
Crystal
monoclinic, C2; a~9.293(2), b~6.2124(7), c~19.321(3) A,
data. (R)-b-Zn(O3PCH2P(O)(CH3)(C6H5))?H2O,
˚
3
V~1114.2(3) A ,
˚
b~92.68(2),
m~24.8 cm21
Z~4;
M~315.52,
.
CCDC reference numbers 149558–149560. See http://
www.rsc.org/suppdata/jm/b0/b007868i/ for crystallographic
data in .cif or other electronic format.
Structure determination of a-Zn2-(R)
Synthesis of H2O3PCH2P(O)(C2H5)(C6H5), 2
Data collection was carried out at room temperature with a
single crystal approximately 0.360.0860.08 mm in size on a
STOE Imaging Plate Diffraction System,14 using graphite-
Ethylphenylphosphinyl chloride was prepared according to the
literature by reaction of the sodium salt of ethyl phenylphos-
phinate with ethyl iodide (73% yield).18 The resulting ethyl
ethylphenylphosphinate was refluxed in thionyl chloride to give
the desired product in 85% yield. Then, to a solution of diethyl
methylphosphonate19 (64 mmol) in dry THF (120 mL) under
nitrogen at 278 ‡C was added dropwise 62.5 mmol of t-BuLi in
hexane. After 15 min ethylphenylphosphinyl chloride was
added dropwise, and the solution was slowly allowed to
warm to 235 ‡C in 3 h. Water was then added, and the mixture
was extracted with CH2Cl2. The extract was dried (MgSO4) and
concentrated under vacuum. The excess of diethyl methylpho-
sphonate was removed under vacuum, using a Kugelrhor
apparatus. The remaining oil (the diethyl ester form of 2) was
purified by chromatography on silica gel and an ethanol/ethyl
acetate (40 : 60) mixture was used as eluent (70% yield). 1H-
NMR (200 MHz, CDCl3) d 1.13 (dt, 3H, PCH2CH3, J3P–
H~19 Hz, J3H–H~7.5 Hz), 1.16 (t, 3H, OCH2CH3, J3H–
H~7 Hz), 1.32 (t, 3H, OCH2CH3, J3H–H~7 Hz), 2.20 (m,
2H, P-CH2-CH3), 2.60 (dd, 2H, P-CH2-P, J2P–H~14.5 Hz,
J2P–H~20.5 Hz), 3.96 (quint., 2H, OCH2, J3P–H~J3H–
H~7 Hz), 4.16 (quint., 2H, OCH2, J3P–H~J3H–H~7 Hz),
7.52 (m, 3H, C6H5), 7.80 (m, 2H, C6H5). 31P-NMR (81 MHz,
CDCl3) d 20.2 (PO3), 34.9 (PO). This oil was then refluxed in
concentrated hydrochloric acid for 2 days. After evaporation of
the mixture under reduced pressure, water was added. The
aqueous phase was washed twice with ethyl acetate, and then
evaporated to give compound 2 in quantitative yield. 1H-NMR
(200 MHz, DMSO) d 0.85 (dt, 3H, PCH2CH3, J3P–H~19 Hz,
J3H–H~7.5 Hz), 2.10 (m, 2H, P-CH2-CH3), 2.60 (m,2H, P-
CH2-P), 7.45 (m, 3H, C6H5), 7.58 (m, 2H, C6H5). 31P-NMR
(81 MHz, DMSO) d 14.4 (PO3), 32.7 (PO).
˚
monochromatized MoK-L2,3 radiation (l~0.71073 A). Data
intensities were corrected for Lorentz-polarization and absorp-
tion (Gaussian analytical correction). P1 was found to be the
correct space group, both at the residue factor and the structure
coherence level. A starting model was found with the
SHELXTL V5.0 direct method program15 and refined (F2,
all reflections included) with the Jana2000 program.16 All
subsequent calculations were carried out with the JANA2000
program package. Non-hydrogen atoms were refined with
anisotropic displacement parameters and hydrogen atoms were
kept at fixed positions with a common fixed isotropic
displacement parameter. At the last stage of the refinement,
a secondary extinction coefficient17 was introduced and the
residue factor smoothly converged with R/Rw~0.0365/0.0685
for 2644 reflections with I/s(I)w2 [from 3597 collected
reflections: R(int)all~0.049] and 305 parameters. The absolute
configuration was unambiguously determined by refining the
inversion twin fraction t(inv)~20.009(17), which was subse-
quently fixed to 0.
Crystal data. (R)-a-Zn(O3PCH2P(O)(C2H5)(C6H5))?H2O,
˚
triclinic, P1; a~5.5106(7), b~8.922(1), c~13.306(2) A,
3
˚
a~90.43(2), b~100.70(2), c~90.16(2)‡, V~642.8(2) A ,
Z~2, M~329.54, m~21.6 cm21
.
Structure determination of the anhydrous form of a-Zn1-(R)
Data collection was carried out as above at room temperature,
with a single crystal approximately 0.3260.1460.14 mm in
size. P212121 was found to be the correct space group. At the
last stage of the refinement (same conditions as above), the
residue factor smoothly converged with R/Rw~0.0224/0.0418
for 2197 reflections with I/s(I)w2 [from 2466 collected
reflections: R(int)all~0.040] and 176 parameters. The absolute
configuration was unambiguously determined by refining the
inversion twin fraction t(inv)~20.006(9), which was subse-
quently fixed to 0.
Resolution of H2O3PCH2P(O)(C2H5)(C6H5), 2
A solution of racemic H2O3PCH2P(O)(C2H5)(C6H5) [2 mmol]
in 30 ml of hot ethanol was added to the desired chiral base
[quinine or quinidine, 3 mmol] dissolved in 15 ml of hot
ethanol. The mixture was allowed to stand for 5 days at room
temperature, after which the crystals that gradually appeared
J. Mater. Chem., 2001, 11, 1106–1110
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were isolated by filtration, corresponding in all cases to a 1 : 1
acid/base complex. Two compounds were thus obtained: 2-
(R) : quinine [84% yield; elemental analysis: Found: P 10.90, C
60.91, H 6.82, N 4.80; calc. for C29P2O6N2H38: P 10.82, C
60.83, H 6.69, N 4.89%; [a]D20~2149 (c~1 in 1 M HCl)], 2-
(S) : quinidine [76% yield; elemental analysis: Found: P 10.80, C
60.96, H 6.70, N 4.87; calc. for C29P2O6N2H38: P 10.82, C
60.83, H 6.69, N 4.89%; [a]D20~z173 (c~1 in 1 M HCl)]. The
complexes (150 mg) were then suspended in 45 ml of water; 2
equivalents of sodium hydroxide were then added and the
mixture was stirred for 1 hour. The reaction medium was then
extracted twice using dichloromethane, allowing recovery of
the chiral base in the organic phase. The pure enantiomeric R-
form of 2 ([a]D20~25 (c~1 in 1 M HCl) from 2-(R) : quinine)
and S-form of 2 ([a]D20~z5 (c~1 in 1 M HCl) from 2-
(S) : quinidine) respectively were then quantitatively recovered
by passing the aqueous phase through DOWEX-50 (Hz form,
eluted with water until neutral) and evaporation. The pure
enantiomeric R-form of 1 and a-Zn1-(R) were prepared as
previously described5 ([a]D20~218 (c~1 in 1 M HCl)). The
anhydrous form of a-Zn1-(R) was obtained by slow heating
until 70 ‡C (1 ‡C h21).
References
1
See for example: A. Clearfield, in Progress in Inorganic Chemistry,
vol. 47, ed. K. D. Karlin, John Wiley & Sons, Inc., New York,
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2
See for example: M. Graetzel, O. Kohle, M. K. Nazzeruddin,
P. Pechy, F. P. Royzinger, S. Ruile and S. M. Zakeeruddin, PCT
Int. Appl. WO 95 29,924 (Cl. CO7F9/58), 9 Nov 1995, Appl. 94/
IB88, 2 May 1994, 52 pp.; L. C. Brousseau III and T. Mallouk,
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3
4
5
F. Fredoueil, V. Pe´nicaud, M. Bujoli-Doeuff and B. Bujoli, Inorg.
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6
7
8
M. C. Etter and P. W. Baures, J. Am. Chem. Soc., 1988, 110, 639.
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Synthesis of (R) and (S)-a-Zn(O3PCH2P(O)(C2H5)(C6H5))?
H2O [a-Zn2-(R) and a-Zn2-(S)]
9
K. Eichele, G. C. Ossenkamp, R. E. Wasylishen and T. S. Cameron,
Inorg. Chem., 1999, 38, 639.
A mixture of zinc nitrate (0.3 mmol), the resolved phosphonic
acid 2-(R) [or 2-(S)] (0.2 mmol) and 1 M sodium hydroxide
(0.4 mmol) in 20 mL water was placed in the PTFE cell of an
autoclave that was sealed and kept at 110 ‡C in a drying oven
for 3 days. a-Zn2-(R) [or a-Zn2-(S)] was obtained as white
crystals in 87% yield [or 78%]. Identical spectroscopic data were
obtained for the two compounds: IR (KBr, cm21) 3529 (m),
3482 (m), 1165 (m), 1156 (m), 1126 (s), 1103 (s), 1092 (vs), 1073
(m), 1035 (m), 1027 (m), 1017 (m), 995 (m); TGA room
temperature to 300 ‡C, 5.7% around 55 ‡C [2H2O, calculated
5.5%]; [a]D20~25 (c~1 in 1 M HCl) for a-Zn2-(R) and z5
(c~1 in 1 M HCl) for a-Zn2-(S). Elemental analysis for a-Zn2-
(R): Found: P 18.92, C 32.90, H 4.24; calc. for ZnC9P2O4H12: P
18.79, C 32.80, H 4.28%.
10 S. Drumel, P. Janvier, P. Barboux, M. Bujoli-Doeuff and B. Bujoli,
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11 See for example: G. Cao, H. Lee, V. M. Lynch and T. E. Mallouk,
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A. Clearfield, Inorg. Chim. Acta, 1989, 155, 7; G. Cao, V. M. Lynch
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P. Palvadeau, J. Le Bideau, C. Payen and J. Rouxel, Chem. Mater.,
1993, 5, 583.
12 D. Massiot, S. Drumel, P. Janvier, M. Bujoli-Doeuff and B. Bujoli,
Chem. Mater., 1997, 9, 6.
13 D. Massiot, H. Thiele and A. Germanus, Bruker Report, 1994, 140,
43.
14 Stoe IPDS software, STOE & Cie GmbH, Darmstadt, Germany,
1996.
15 G. M. Sheldrick, SHELXTL V5.0, Siemens Analytical X-ray
Instruments Inc., Madison, WI, USA, 1995.
16 V. Petricek and M. Dusek, JANA2000 programs for modulated
and composite crystals, Institute of Physics, Praha, Czech
Republic, 2000.
17 P. J. Becker and P. Coppens, Acta Crystallogr., Sect. A, 1974, 30,
129.
Synthesis of (R)-b-Zn(O3PCH2P(O)(CH3)(C6H5)) [b-Zn1-(R)]
Same procedure as above, except that 1-(R) (0.2 mmol) and
1 M sodium hydroxide (0.2 mmol) were used instead (yield:
38%). IR (KBr, cm21) 3300 (br, m), 1162 (s), 1148 (vs), 1127 (s),
1114 (vs), 1077 (s), 1053 (s), 990 (s); TGA room temperature to
300 ‡C, 5.9% around 55 ‡C [2H2O, calculated 5.7%];
[a]D20~218 (c~1 in 1 M HCl).
18 W. B. Farnham, R. K. Murray Jr. and K. Mislow, J. Am. Chem.
Soc., 1970, 92, 5809.
19 P. Coutrot, M. Snoussi and P. Savignac, Synthesis, 1978, 133.
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