Metal alkoxides as versatile precursors for group 4 phosphonates: Synthesis and X-ray structure of a novel organosoluble zirconium phosphonate

Article abstract of DOI:10.1021/ic9907361

Reactions of Ph₂P(O)(OH) and t-BuP(O)(OSiMe₃)(OH) with Ti(O-i-Pr)₄ in equimolar ratios gave titanium phosphonates of the type [(O-i-Pr)₃Ti(μ-O)₂PR¹R²]₂ (1, R¹ = R² = Ph; 2, R¹ = t-Bu, R² = OSiMe₃) as colorless crystalline solids in moderate yields. Reactions of Ph₂P(O)(OH) and the isopropoxides of zirconium and hafnium resulted in products of the composition [(O-i-Pr)₃M(μ-O-i-Pr)₂(μ-OPOPh₂)M(O-i-Pr)₂]Ph₂P(O)(OH) (M = Zr (3), Hf (4)) in high yields. The compounds were characterized by ¹H, ³¹P, and ²⁹Si NMR, infrared (IR), and mass spectroscopic (MS) techniques. The molecular structures of 2 and 3 were confirmed by X-ray crystallography.

Full text of DOI:10.1021/ic9907361

Inorg. Chem. 2000, 39, 23-26
23
Metal Alkoxides as Versatile Precursors for Group 4 Phosphonates: Synthesis and X-ray
Structure of a Novel Organosoluble Zirconium Phosphonate†
Debashis Chakraborty, Vadapalli Chandrasekhar, Manish Bhattacharjee, Ralph Kra1tzner,
Herbert W. Roesky,* Mathias Noltemeyer, and Hans-Georg Schmidt
Institut fu¨r Anorganische Chemie, Universita¨t Go¨ttingen, Tammannstrasse 4,
D-37077 Go¨ttingen, Germany
ReceiVed June 23, 1999
Reactions of Ph2P(O)(OH) and t-BuP(O)(OSiMe3)(OH) with Ti(O-i-Pr)4 in equimolar ratios gave titanium
phosphonates of the type [(O-i-Pr)3Ti(µ-O)2PR1R2]2 (1, R1 ) R2 ) Ph; 2, R1 ) t-Bu, R2 ) OSiMe3) as colorless
crystalline solids in moderate yields. Reactions of Ph2P(O)(OH) and the isopropoxides of zirconium and hafnium
resulted in products of the composition [(O-i-Pr)3M(µ-O-i-Pr)2(µ-OPOPh2)M(O-i-Pr)2]Ph2P(O)(OH) (M ) Zr
(3), Hf (4)) in high yields. The compounds were characterized by 1H, 31P, and 29Si NMR, infrared (IR), and mass
spectroscopic (MS) techniques. The molecular structures of 2 and 3 were confirmed by X-ray crystallography.
Introduction
phosphates has made these materials of vital importance in the
area of structurally mediated interlayer transport8 in addition
Organophosphonates and phosphates have received consider-
able attention owing to their structural chemistries, intercalation
behaviors, ion exchange properties, and catalytic applications.
Early attempts have revealed the possibility of incorporating
transition metals such as V, Zr, and Zn into phosphate
frameworks.1,2 Titanium phosphates containing alkali metals
have shown useful applications as ion exchangers,3 fast-ion
conductors,4 low-thermal-expansion ceramics,5 and nonlinear
optic materials.6 The conceptual view of molecular titanium
phosphates as precursors to solid-state materials is recent.7
Extensive research focusing on the applications of zirconium
to areas where their microporous and mesoporous properties
are utilized.9 In the past few years, there has been widespread
success in devising molecular routes for the synthesis of
advanced materials.10 With regard to soluble phosphonates
containing transition metals, our first success emerged upon
employing the reactions of various RP(O)(OH)2 systems with
Cp*TiCl3 or Cp*TiMe3 as the counterpart organometallic
precursor.11 Since then, our constant goal has been to devise
rational synthetic routes to synthesize other transition metal
phosphonates. Complementary synthetic strategies employed for
the zirconium and hafnium systems proved to be a failure. The
applicability of the titanium alkoxide Ti(O-i-Pr)4 as a useful
synthon for the generation of titanium phosphonates12 prompted
us to explore the possibility of group 4 metal alkoxides in
general as phosphonate-producing precursors. To the best of
our knowledge, there have been no earlier reports on the
synthesis or structural characterization of soluble phosphonate
systems of Zr and Hf. In this report, we wish to contribute our
investigations concerning the reactivity of group 4 metal
alkoxides and R2P(O)(OH) systems. While this study was in
progress, a few interesting examples were contributed by
Tilley,12 Mutin,13 and their co-workers.
† Dedicated to Professor Arndt Simon on the occasion of his 60th
birthday.
(1) Reviews: (a) Zubieta, J. Comments Inorg. Chem. 1994, 16, 153. (b)
Cao, G.; Hong, H.-G.; Mallouk, T. E. Acc. Chem. Res. 1992, 25, 420.
(c) Clearfield, A. Comments Inorg. Chem. 1990, 10, 89. (d) Alberti,
G.; Constantino, U. In Inclusion Compounds 5; Atwood, J. L., Davis,
J. E. D., MacNicol, D. D., Eds.; Oxford University Press: Oxford,
U.K., 1991.
(2) For some recent work on phosphates and phosphonates, see: (a) Bryd,
H.; Clearfield, A.; Poojary, D.; Reis, K. P.; Thompson, M. E. Chem.
Mater. 1996, 8, 2239. (b) Song, T.; Xu, J.; Zhao, Y.; Yue, Y.; Xu,
Y.; Xu, R.; Hu, N.; Wie, G.; Jia, H. J. Chem. Soc., Chem. Commun.
1994, 1171. (c) Gendraud, P.; de Roy, M. E.; Besse, J. P. Inorg. Chem.
1996, 35, 6108. (d) Bonavia, G.; Haushalter, R. C.; O’Connor, C. J.;
Zubieta, J. Inorg. Chem. 1996, 35, 5603. (e) Soghomonian, V.;
Haushalter, R. C.; Zubieta, J. Chem. Mater. 1995, 7, 1648. (f) Roca,
M.; Marcos, M. D.; Amoro´s, P.; Beltra´n-Porter, A.; Edwards, A. J.;
Beltra´n-Porter, D. Inorg. Chem. 1996, 35, 5613. (g) Bellito, C.;
Federici, F.; Ibrahim, S. A. J. Chem. Soc., Chem. Commun. 1996,
759. (h) Walawalkar, M. G.; Roesky, H. W.; Murugavel, R. Acc. Chem.
Res. 1999, 32, 117.
(3) (a) Inorganic Ion Exchange Materials; Clearfield, A., Eds.; CRC
Press: Boca Raton, FL, 1982. (b) Alvarez, C.; Llavona, R.; Garcia, J.
R.; Sua´rez, M.; Rodriguez, J. Inorg. Chem. 1987, 26, 1045.
(4) (a) Wang, S.; Hwu, S. J. Solid State Chem. 1987, 26, 1045. (b) Wang,
B.; Greenblatt, M.; Wang, S.; Hwu, S.-J. Chem. Mater. 1993, 5, 23.
(5) Limaye, S. Y.; Agrawal, D. K.; McKinstry, H. A. J. Am. Ceram. Soc.
1987, 70, C232.
(6) (a) Munowitz, M.; Jarman, R. H.; Harrison, J. F. Chem. Mater. 1992,
4, 1296. (b) Hagerman, M. E.; Poeppelmeier, K. R. Chem. Mater.
1995, 7, 602. (c) Harrison, W. T. A.; Phillips, M. L. F.; Stucky, G. D.
Chem. Mater. 1995, 7, 1849. (d) Harrison, W. T. A.; Phillips, M. L.
F.; Stucky, G. D. Chem. Mater. 1997, 9, 1138.
Results and Discussion
Our recent experience in conducting the investigations with
dialkylaluminum halides and phosphate esters of the type
(8) (a) Horne, J. C.; Blanchard, G. J. J. Am. Chem. Soc. 1999, 121, 4427.
(b) Horne, J. C.; Huang, Y.; Liu, G.-Y.; Blanchard, G. J. J. Am. Chem.
Soc. 1999, 121, 4419.
(9) Clearfield, A. Chem. Mater. 1998, 10, 2801 and references therein.
(10) (a) Su, K.; Tilley, T. D. Chem. Mater. 1997, 9, 588 and references
therein. (b) Cowley, A. H.; Jones, R. A. Angew. Chem. 1989, 101,
1235; Angew. Chem., Int. Ed. Engl. 1989, 28, 1208. (c) Lugmair, C.
G.; Tilley, T. D.; Rheingold, A. L. Chem. Mater. 1997, 9, 339.
(11) Walawalkar, M. G.; Horchler, S.; Dietrich, S.; Chakraborty, D.;
Roesky, H. W.; Scha¨fer, M.; Schmidt, H.-G.; Sheldrick, G. M.;
Murugavel, R. Organometallics 1998, 17, 2865.
(12) Lugmair, C. G.; Tilley, T. D. Inorg. Chem. 1998, 37, 1821.
(13) Guerrero, G.; Mehring, M.; Mutin, P. H.; Dahan, F.; Vioux, A. J.
Chem. Soc., Dalton Trans. 1999, 1537.
(7) Thorn, D. L.; Harlow, R. L. Inorg. Chem. 1992, 31, 3917.
10.1021/ic9907361 CCC: $19.00 © 2000 American Chemical Society
Published on Web 12/16/1999

24 Inorganic Chemistry, Vol. 39, No. 1, 2000
Chakraborty et al.
(R3SiO)3PO has been that the most favorable product is an eight-
membered ring containing suitable substituents on the metal as
well as on the phosphorus centers where the phosphate ester
could be considered as an R2P(O)(OH) analogue.14 This is in
accord with the observations of Mason and co-workers15 and
the earlier investigations reported on the reactions of group 13
metal alkyls and Ph2P(O)(OH).16 On this basis, it could be easily
surmised that reactions of titanium alkoxides with R2P(O)(OH)
systems should generate a product possessing an eight-
membered ring as the core with appropriate substituents on the
Ti and P centers. This was first reported by Tilley et al.12 We
have carried out a systematic investigation into the reactivity
of various titanium alkoxides with the R2P(O)(OH) systems.
Reactions of Ph2P(O)(OH) and t-BuP(O)(OSiMe3)(OH) with
Ti(O-i-Pr)4 in equimolar ratios in hydrocarbon solvents give
titanium phosphonates of the type [(O-i-Pr)3Ti(µ-O)2PR1R2]2
(1, R1 ) R2 ) Ph; 2, R1 ) t-Bu, R2 ) OSiMe3) as colorless
crystalline solids in moderate yields (eq 1).
Figure 1. Molecular structure of [(O-i-Pr)3Ti(µ-O)2P(OSiMe3)(t-Bu)]2.
2Ti(O-i-Pr)4 + 2HO(O)PR1R2 -2 i-PrOH8
[(O-i-Pr)3Ti(µ-O)2PR1R2]2
(1)
1: R1 ) R2 ) Ph
2: R1 ) t-Bu, R2 ) OSiMe3
In the case of Ph2P(O)(OH), the reactions were carried out
in toluene, while for t-BuP(O)(OSiMe3)(OH), the reactions were
carried out in pentane. The starting material t-BuP(O)(OSiMe3)-
(OH) was prepared from an equimolar reaction between
t-BuP(O)(OH)2 and Me3SiCl in the presence of triethylamine
employing high-dilution techniques.
Figure 2. Shape of the Ti2P2O4 core revealing the chair conformation.
Similar investigations carried out with Ti(OMe)4 did not lead
to any isolable products.
In the case of 1, the 1H NMR spectrum recorded in benzene-
d6 revealed two sets of resonances for the O-i-Pr groups in a
3:1 ratio for each set, while the phenyl moieties were observed
as two sets of poorly resolved resonances in the prescribed range.
The 31P NMR spectrum showed the presence of three distinct
resonances. The spectral characteristics remained unchanged
after several recrystallizations. EI-MS could not provide further
insight. Furthermore, we prepared the ester t-BuP(O)(OSiMe3)-
(OH) with the view of having the OSiMe3 group as an extra-
ring NMR probe. The reactions were carried out under identical
The spectroscopic conclusions were corroborated by an X-ray
diffraction study of 2. Single crystals of 2 were grown from
pentane over a 15 day period at -80 °C. 2 crystallizes as a
centrosymmetric dimer in the monoclinic space group P21/n with
the titanium centers assuming a five-coordinated trigonal bi-
pyramidal geometry (Figure 1). The t-Bu and the OSiMe3
substituents present on each phosphorus center are trans to each
other. The central Ti2P2O4 core assumes a chair conformation
in the solid state (Figure 2). The intra-ring Ti-O and P-O bond
lengths are nearly identical [Ti(1)-O(1) ) 1.891(2) Å, Ti(1)-
O(2A) ) 2.031(2) Å; P(1)-O(1) ) 1.444(2) Å, P(1)-O(2) )
1.494(2) Å] and are in close agreement with the literature
precedents.12
In contrast to the monomeric titanium alkoxides, the isopro-
poxides of zirconium and hafnium are dimeric alcoholates17 of
the general formula [M(O-i-Pr)4(i-PrOH)]2 (M ) Zr, Hf).
Through our experience in the previous investigations with
titanium alkoxides, it was realized that the use of low initial
temperatures and hydrocarbon solvents is the ideal initial
condition necessary for analogous reactions. A 2:1 reaction
between Ph2P(O)(OH) and the corresponding isopropoxide of
either zirconium or hafnium at -60 °C in toluene resulted in a
product of the composition [(O-i-Pr)3M(µ-O-i-Pr)2(µ-OPOPh2)-
M(O-i-Pr)2]Ph2P(O)(OH) (M ) Zr (3), Hf (4)) in high yield
(eq 2). A 1:1 reaction between the above-mentioned starting
materials also yielded 3 and 4, in addition to the unreacted
isopropoxide, thereby indicating that these are the most favorable
products under the reaction conditions employed.
1
conditions in pentane to obtain 2 in moderate yields. The H
NMR spectrum of 2 displayed signals for the various moieties
in the required ratio of integration. The 31P NMR spectrum
revealed numerous signals in the range 17-35 ppm. The 29Si
NMR spectrum revealed prominent signals at 16.8 and 19.7 ppm
in addition to signals at 14.7 and 18.7 ppm. Temperature-
dependent NMR studies in the range -50 to +40 °C were
1
carried out. No significant changes were observed in the H
NMR spectrum. However, at -40 °C, in the 31P NMR spectrum
major signals were observed at 14.7, 20.8, 22.9, and 32.2 ppm
whereas in the 29Si NMR spectrum the signals at 14.7 and 19.7
ppm diminished in intensity. The NMR characteristics imply
dynamic behavior of 2 in the solution state. These observations
are in agreement with those reported by Tilley et al. for the
corresponding (t-BuO)2P derivatives.12
(14) Pinkas, J.; Chakraborty, D.; Yang, Y.; Murugavel, R.; Noltemeyer,
M.; Roesky, H. W. Organometallics 1999, 18, 523.
(15) Mason, M. R.; Matthews, R. M.; Mashuta, M. S.; Richardson, J. F.
Inorg. Chem. 1996, 35, 5756.
(16) Coates, G. E.; Mukherjee, R. N. J. Chem. Soc. 1964, 1295. (b)
Weidlein, J.; Schaible, B. Z. Anorg. Allg. Chem. 1971, 386, 176. (c)
Schaible, B.; Weidlein, J. J. Organomet. Chem. 1972, 35, C7. (d)
Olapinski, H.; Schaible, B.; Weidlein, J. J. Organomet. Chem. 1972,
43, 107.
(17) (a) Vaartstra, B. A.; Huffman, J. C.; Gradeff, P. S.; Hubert-Pfalzgraf,
L. G.; Daran, J. C.; Parraud, S.; Yunlu, K.; Caulton, K. G. Inorg.
Chem. 1990, 29, 3126. (b) Veith, M.; Mathur, S.; Mathur, C.; Huch,
V. J. Chem. Soc., Dalton Trans. 1997, 2101.

Group 4 Phosphonates
Inorganic Chemistry, Vol. 39, No. 1, 2000 25
[M(O-i-Pr)4(i-PrOH)]2 + 2Ph2P(O)(OH) -3 i-PrOH8
[(O-i-Pr)3M(µ-O-i-Pr)2(µ-OPOPh2)M(O-i-Pr)2]Ph2P(O)(OH)
M ) Zr (3), Hf (4)
(2)
1
In the case of 3 and 4, the H NMR spectra recorded in
benzene-d6 reveal three distinct sets of doublets (in the range
1.2-1.6 ppm) and three distinct sets of multiplets (in the range
4.5-4.9 ppm), indicating three different O-i-Pr environments
in the molecule. The phenyl moieties are observed as two
different sets of multiplets (8.1-8.3 ppm) in the aromatic region.
Also, a singlet was observed in each case (ca. 11.9 ppm) which
is characteristic of an OH group associated with hydrogen-
bonding interactions present on a phosphorus center. On the
basis of the 1H NMR data, it could be assumed that one
Ph2P(O)O moiety provides a bridge between two metal centers
and the other molecule could just be associated coordinatively
through the oxygen center present as PdO. This assumption
was supported by the 31P NMR spectra in which two distinct
signals were observed (18.8, 26.9 ppm for 3, 20.1, 28.5 ppm
for 4).
Figure 3. Molecular structure of [(O-i-Pr)3Zr(µ-O-i-Pr)2(µ-OPOPh2)-
Zr(O-i-Pr)2]Ph2P(O)(OH).
The IR spectra of 3 and 4 reveal the presence of broad bands
(ca. 2380 and ca. 1670 cm-1, respectively) which could be
additional support for the presence of intra- or intermolecular
hydrogen bonding in these molecules. These absorptions are
also present in the IR spectra of Ph2P(O)(OH) and in
t-BuP(O)(OSiMe3)(OH). Besides, the absorption at ca. 1260
cm-1 is characteristic for ν(PdO) as evidenced in metal
phosphates.11,14 In the spectrum of 4, the band at 430 cm-1 is
typical for ν(Hf-OR).17b The EI-MS spectra of 3 and 4 reveal
a peak due to the [M+ - 2PrOH] fragment (m/e 911 for 3 and
1086 for 4) of 100% intensity.
Since 3 and 4 have identical spectroscopic properties, their
solid-state structures could also be anticipated to be isomor-
phous. Hence, we proceeded with the structural characterization
of only the zirconium compound. Single crystals of 3 were
grown from toluene over a period of 2 days at -32 °C. 3
crystallizes in the monoclinic space group P21/n. The two
zirconium centers are connected through two O-i-Pr bridges,
forming a four-membered ring with an average Zr-O bond
distance of 2.170 Å (Figure 3), which resembles that of the
starting material.17a The Zr(1)-O(3) and Zr(2)-O(4) bond
lengths are similar with 2.142 Å as the average value. However,
the Zr(2)-O(5) bond distance is slightly shorter (2.077(3) Å).
Also, there is an intramolecular hydrogen-bonding interaction
between the OH group linked to the phosphorus center P(2)
and one of the O-i-Pr moieties connected to the zirconium center
Zr(1) (H(67)- - -O(31) ) 2.064 Å).
1
Na/K alloy and freshly distilled prior to use. H, 31P, and 29Si NMR
spectra were measured on Bruker MSL-400, AM-250, and AM-200
instruments. The chemical shifts are reported in ppm with reference to
SiMe4 (external) for H and 29Si nuclei and to 85% H3PO4 (external)
1
for the 31P nucleus. IR spectra were recorded on a Bio-Rad Digilab
FTS 7 spectrometer. Mass spectra were obtained on a Finnigan MAT
8230 or a Varian MAT CH 5 spectrometer. Elemental analyses were
performed at the analytical laboratory of the Institute of Inorganic
Chemistry, University of Go¨ttingen.
Starting Materials. t-BuP(O)(OH)2 was prepared using a literature
procedure.19 Me3SiCl (Aldrich) was distilled prior to use. Triethylamine
was dried over calcium dihydride and freshly distilled before use.
Ph2P(O)(OH) (Acros) was dried under high vacuum. Titanium isopro-
poxide (Aldrich), zirconium isopropoxide (Strem), and hafnium iso-
propoxide (Strem) were used as received without further purification.
Preparation of t-BuP(O)(OSiMe3)(OH). To a stirred solution
containing t-BuP(O)(OH)2 (20 g, 0.14 mol) and Et3N (14.7 g, 0.14 mol)
in THF (300 mL) at -10 °C was added dropwise Me3SiCl (15.7 g,
0.14 mol) diluted in THF (50 mL) with the aid of a dropping funnel
over a period of 1 h. The reaction mixture was allowed to warm slowly
to room temperature and stirred overnight. The amine hydrochloride
formed was filtered off using a frit of medium porosity, and the solvent
was removed in vacuo from the filtrate. The solid obtained was extracted
with hexane (100 mL), and the extract was filtered to remove the
residual amine hydrochloride. After the solvent was removed in vacuo,
a waxy solid was obtained, which was subsequently dried overnight.
Yield: 21 g (71%, 0.1 mol). Anal. Calcd for C7H19O3PSi: C, 39.98;
H, 9.11; P, 14.73; Si, 13.36. Found: C, 39.54; H, 8.92; P, 14.7; Si,
13.2. MS (EI, 70 eV): m/e 211 (100, M+). IR (Nujol), cm-1: 2721 w,
2338 br, 1677 br, 1480 vs, 1421 m, 1395 m, 1365 m, 1255 s, 1224 w,
1189 vs, 1033 w, 1015 w, 976 w, 853 s, 830 s, 761 vs, 723 w, 689 m,
Through the above-mentioned investigations, we have dem-
onstrated the use of metal alkoxides as viable precursors to group
4 metallaphosphonates. Under the conditions employed, the
titanium systems yield an eight-membered ring, containing
titanium and phosphorus centers. Interestingly, the presence of
a reactive P-OH moiety in the zirconium and hafnium
compounds suggests their potential as building blocks for
macromolecular assemblies. Also, these are the first examples
of organosoluble zirconium and hafnium phosphonates produced
by employing molecular routes.
1
644 vs, 598 m, 502 vs. H NMR (250 MHz, benzene-d6): δ 0.22 (s,
(CH3)3Si, 9H), 1.20 (d, C(CH3)3, 9H, 3JPH ) 16.6 Hz), 13.60 (s, P-OH).
31P NMR (101 MHz, benzene-d6): δ 32.4 (s). 29Si NMR (49.7 MHz,
2
benzene-d6): δ 21.1 (d, JPSi ) 10.4 Hz).
Preparation of [(O-i-Pr)3Ti(µ-O)2PPh2]2 (1). To a stirred suspen-
sion of Ph2P(O)(OH) (220 mg, 1 mmol) in toluene (25 mL) at -60 °C
was slowly added Ti(O-i-Pr)4 (280 mg, 1 mmol) diluted in toluene (10
mL). The reaction mixture was allowed to warm slowly to room
temperature and stirred for an additional period of 6 h. After removal
of the solvent in vacuo, an oily solid was obtained, which was
subsequently crystallized from toluene at -30 °C to obtain 1 as a white
crystalline solid. Yield: 200 mg (45.2%, 0.22 mmol). Anal. Calcd for
Experimental Section
General Information. All experimental manipulations were carried
out under a dry, prepurified argon atmosphere, using Schlenk techniques
and rigorously excluding moisture and air.18 The samples for spectral
measurements were prepared in a drybox. Solvents were dried over an
(18) Shriver, D. F.; Drezdzon, M. A. The Manipulation of Air-SensitiVe
Compounds, 2nd ed.; Wiley-Interscience: New York, 1986.
(19) Crofts, P. C.; Kosolapoff, G. M. J. Am. Chem. Soc. 1953, 75, 3379.

26 Inorganic Chemistry, Vol. 39, No. 1, 2000
Chakraborty et al.
C42H62O10P2Ti2: C, 57.02; H, 7.06; P, 7.00. Found: C, 56.58; H, 7.09;
P, 6.8. IR (Nujol), cm-1: 1593 w, 1261 w, 1160 m, 1199 w, 1160 m,
1128 vs, 1068 m, 1043 s, sh, 1021 s, sh, 848 m, 800 w, 751 m, 725 s,
Table 1. Crystal Data and Structure Refinement Details for 2 and 3
2
3
1
empricial formula
C32H78O12P2Si2Ti2
C52H78O11P2Zr2
incl.toluene
1123.52
monoclinic
P21/n
9.944(3)
22.096(9)
25.878(10)
90
694 m, 611 m, sh, 531 w, sh, 466 w. H NMR (200 MHz, benzene-
d6): δ 1.21 (d, OCH(CH3)2), 1.35 (d, OCH(CH3)2), 4.53 (m, OCH(CH3)2),
5.12 (m, OCH(CH3)2), 6.91 (m, C6H5), 7.90 (m, C6H5). 31P NMR (81
MHz, benzene-d6): δ 19.2 (s), 21.0 (s), 24.3 (s).
fw
868.86
monoclinic
P21/n
11.296(13)
17.403(3)
12.241(2)
90
90.217(15)
90
crystal system
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Preparation of [(O-i-Pr)3Ti(µ-O)2P(OSiMe3)(t-Bu)]2 (2). To a
stirred solution of t-BuP(O)(OSiMe3)(OH) (500 mg, 2.38 mmol) in
pentane (30 mL) at -60 °C was added dropwise a solution containing
Ti(O-i-Pr)4 (680 mg, 2.38 mmol) in pentane (20 mL). The reaction
mixture was allowed to warm slowly to room temperature and stirred
overnight. The solvent was removed in vacuo, and prolonged pumping
yielded a waxy solid, which was subsequently dissolved in pentane
(10 mL). The solution was stored at -80 °C over a period of 15 days
to give analytically pure 2. Yield: 620 mg (60%, 0.71 mmol). Anal.
Calcd for C32H78O12P2Si2Ti2: C, 44.24; H, 9.05; P, 7.13. Found: C,
43.9; H, 9.0; P, 7.0. IR (Nujol), cm-1: 1590 w, 1365 s, sh, 1331 w,
1255 s, 1211 m, 1159 m, sh, 1125 vs, 1074 m, 1009 s, 852 s, 801 w,
690 w, 507 w. 1H NMR (200 MHz, CDCl3): δ 0.21 (s, (CH3)3Si, 18H),
1.22 (d, C(CH3)3, 18H, 3JPH ) 12.51 Hz), 1.31 (d, OCH(CH3)2, 36H),
3.98 (m, OCH(CH3)2, 6H). 31P NMR (101 MHz, CDCl3): δ 17-35
(numerous signals). 29Si NMR (49.7 MHz, CDCl3): δ 14.7 (s), 16.8
(d), 18.7 (d), 19.7 (d).
96.472(11)
90
5650
2406.4
T (°C)
-70
-130
λ (Å)
0.710 73
1.199
0.710 73
1.321
D
calcd (g cm-3
)
µ (mm-1
F(000)
)
0.496
936
0.479
2352
cryst size (mm)
θ range (deg)
index ranges
0.90 × 0.70 × 0.60
3.53-23.00
-12 e h e 12
-18 e k e 18
-13 e l e 13
8874
0.50 × 0.50 × 0.20
2.26-25.99
-11 e h e 11
0 e k e 27
0 e l e 30
10 043
no. of reflns collcd
no. of indep reflns
R(int)
Preparation of [(O-i-Pr)3Zr(µ-O-i-Pr)2(µ-OPOPh2)Zr(O-i-Pr)2]-
Ph2P(O)(OH) (3). A solution of [Zr(O-i-Pr)4(i-PrOH)]2 (387 mg, 0.5
mmol) in toluene (10 mL) was added dropwise to a stirred suspension
of Ph2P(O)(OH) (220 mg, 1 mmol) in toluene (35 mL) at -60 °C. The
reaction mixture was allowed to warm slowly to room temperature.
The solvent was reduced (to 10 mL) in vacuo, and the resultant solution
was stored at -30 °C overnight to yield analytically pure 3. Yield:
410 mg (79.5%, 0.39 mmol). Anal. Calcd for C45H70O11P2Zr2: C, 52.40;
H, 6.84; P, 6.01. Found: C, 52.30; H, 6.60; P, 5.9. MS (EI, 70 eV):
m/e 911 (100, M+ - 2PrOH). IR (Nujol), cm-1: 2619 w, 2377 br,
1676 br, 1440 s, sh, 1359 vs, 1337 s, sh, 1261 m, 1130 vs, 1086 s, sh,
997 vs, 940 m, 844 m, 820 s, 753 m, 725 s, 696 s, 558 vs, 457 m, 418
3291
0.0251
10 043
0.0000
no. of data
no. of params
3290
238
10 043
607
no. of restraints
goodness-of-fit on F2
R1[I > 2σ(I)]a
wR2(all data)
0
59
1.051
0.0424
0.1164
1.030
0.0411
0.1139
0.531, -0.368
largest diff peak and
0.869, -0.736
hole (e Å-3
)
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. b wR2 ) [∑w(|Fo | - |Fc2|)2/∑w-
2
2 2
|Fo | ]1/2
.
1
w. H NMR (200 MHz, benzene-d6): δ 1.16 (d, OCH(CH3)2, 12H),
methods (SHELXS-90/96)21 and refined on all data by full-matrix least-
squares on F2.22 All non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were added in idealized positions and refined using a
riding model. The crystal data and structure refinement details for 2
and 3 are given in Table 1.
1.42 (d, OCH(CH3)2, 12H), 1.51 (d, OCH(CH3)2, 18H), 4.5 (m,
OCH(CH3)2, 2H), 4.71 (d, OCH(CH3)2, 2H), 4.84 (m, OCH(CH3)2, 3H),
8.10 (m, C6H5, 10H), 8.26 (m, C6H5, 10H), 11.81 (s, P-OH, 1H). 31
NMR (101 MHz, benzene-d6): δ 18.8 (s), 26.9 (s).
P
Preparation of [(O-i-Pr)3Hf(µ-O-i-Pr)2(µ-OPOPh2)Hf(O-i-Pr)2]-
Ph2P(O)(OH) (4). A procedure similar to that for 3 was followed.
Yield: 487 mg (81%, 0.40 mmol). Anal. Calcd for C45H70Hf2O11P2:
C, 44.82; H, 5.85; P, 5.14. Found: C, 44.50; H, 6.03; P, 5.1. MS (EI,
70 eV): m/e 1086 (100, M+ - 2PrOH). IR (Nujol), cm-1: 2623 w,
2381 br, 1679 br, 1441 s, sh, 1358 vs, 1336 s, sh, 1261 m, 1133 vs,
1045 s, sh, 997 vs, 937 m, 844 m, 820 s, 754 m, 723 s, 696 s, 555 vs,
454 m, 430 w. 1H NMR (200 MHz, benzene-d6): δ 1.18 (d,
OCH(CH3)2, 12H), 1.43 (d, OCH(CH3)2, 12H), 1.52 (d, OCH(CH3)2,
18H), 4.59 (m, OCH(CH3)2, 2H), 4.73 (d, OCH(CH3)2, 2H), 4.86 (m,
OCH(CH3)2, 3H), 8.15 (m, C6H5, 10H), 8.29 (m, C6H5, 10H), 11.89 (s,
P-OH, 1H). 31P NMR (101 MHz, benzene-d6): δ 20.1 (s), 28.5 (s).
X-ray Structure Determination. Crystal data for 2 were collected
on a Stoe-Siemens-AED four-circle diffractometer using a learned-
profile method.20 The data for 3 were collected on a Stoe-Siemens-
Huber four-circle diffractometer equipped with a Siemens CCD area
detector using the ψ-scan mode. The structures were solved by direct
Acknowledgment. This work was supported by the Deutsche
Forschungsgemeinshaft. Research fellowships for V.C. and M.B.
from the Alexander von Humboldt Foundation are gratefully
acknowledged.
Supporting Information Available: Tables of the X-ray crystal
structure determination data, atomic coordinates, anisotropic thermal
parameters, and bond lengths and angles for 2 and 3. This material is
available free of charge via the Internet at http://pubs.acs.org.
IC9907361
(20) Clegg, W. Acta Crystallogr., Sect A 1981, 37, 22.
(21) Sheldrick, G. M. SHELXL-97: Program for crystal structure refine-
ment. University of Go¨ttingen, 1997.
(22) Sheldrick, G. M. Acta Crystallogr., Sect A 1990, 46, 467.