Angewandte
Chemie
For [K([18]crown-6)] H ·3·8MeOH·8H O, the tungsten atoms were
[5] a) K. Kamata, K. Yonehara, Y. Sumida, K. Yamaguchi, S.
6
2
2
refined anisotropically, and the other atoms, except for one oxygen
atom, were refined isotropically. The hydrogen atoms of the
Hikichi, N. Mizuno, Science 2003, 300, 964 – 966; b) K. Kamata,
Y. Nakagawa, K. Yamaguchi, N. Mizuno, J. Catal. 2004, 224,
224 – 228.
[
18]crown-6 ligands were located by using riding models.
Crystal data for (TBA) [2]·5H O: C H N O Si W ; M =
[6] Reviews of Baeyer–Villiger oxidation: a) G.-J. ten Brick,
W. C. E. Arends, R. A. Sheldon, Chem. Rev. 2004, 104, 4105 –
4123; b) G. Strukul, Angew. Chem. 1998, 110, 1256 – 1267;
Angew. Chem. Int. Ed. 1998, 37, 1198 – 1209; c) M. Rent, B.
Meunier, Eur. J. Org. Chem. 1999, 737 – 750.
4
2
64 160
4
75
2
20
5
1
921.14, orthorhombic, space group P2 2 2 (no. 19), a =
1 1 1
3
4.09300(10), b = 26.7218(3), c = 37.7468(4) , V= 14215.1(2) ,
ꢀ3
Z = 4, 1calcd = 2.767 gcm , m(MoKa) = 162.26, R = ꢀ j j F j ꢀ j F j j /ꢀ
o
c
j F j = 0.054 for 13768 unique data with I > 3.0s(I) (R =
o
w
2
2
o
1/2
IV
[
ꢀw(jF jꢀjF j) /ꢀwF ] = 0.077) and 1068 parameters used for
[7] Acidification of the Ti -containing heteropolytungstate
o
c
5
ꢀ
refinement. Crystal data for [K([18]crown-6)] H [3]·8MeOH·4H O:
[PTiW O ] leads to the formation of the corresponding
6
2
2
11 40
7
ꢀ
C H186O120K Si W ; M = 6972.04, monoclinic, space group P2 /n
dimer [(PTiW O ) (m-OH)]
through protonation of the
8
0
6
2
20
1
11 39 2
(
no. 14), a = 18.547(3), b = 16.564(2), c = 28.633(4) , b = 99.715(2)8,
terminal oxo ligand attached to the titanium center followed
by dehydration: O. A. Kholdeeva, G. M. Maksimov, R. I.
Maksimovskaya, L. A. Kovaleva, M. A. Fedotov, V. A. Grigor-
iev, C. L. Hill, Inorg. Chem. 2000, 39, 3828 – 3878.
3
ꢀ3
V= 8670.4(21) , Z = 2, 1
= 2.670 gcm , m(MoKa) = 134.80, R =
calcd
0
.047 for 12297 unique data with I > 3.0s(I) (R = 0.053) and 598
w
parameters used for refinement. CCDC 278955 and CCDC 278956
contain the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Baeyer–Villiger oxidation: Catalyst containing 25 mmol of W
i.e., 1: 2.5 mmol, 2 and 3: 1.25 mmol), solvent (nitromethane, 1.0 mL),
H O2 (80% aqueous solution, 0.25 mmol), and substrate (cyclo-
pentanone, 1.25 mmol) were charged to the reaction vial under air.
The reaction was carried out at 333 K. The reaction solution was
periodically sampled and analyzed by gas chromatography with an
internal standard.
[
8] Examples of organic–inorganic hybrid compounds derived from
8ꢀ
[
SiW O ] : a) F. Xin, M. T. Pope, Inorg. Chem. 1996, 35, 5693 –
1
0
36
5695; b) C. R. Mayer, V. Cabuil, T. Lalot, R. Thouvenot, Angew.
Chem. 1999, 111, 3878 – 3881; Angew. Chem. Int. Ed. 1999, 38,
672 – 3675; c) C. R. Mayer, P. Herson, R. Thouvenot, Inorg.
(
3
2
Chem. 1999, 38, 6152 – 6158; d) C. R. Mayer, R. Thouvenot, T.
Lalot, Macromolecules 2000, 33, 4433 – 4437; e) C. R. Mayer, R.
Thouvenot, T. Lalot, Chem. Mater. 2000, 12, 257 – 260; f) C. R.
Mayer, I. Fournier, R. Thouvenot, Chem. Eur. J. 2000, 6, 105 –
110; g) R. C. Schroden, C. F. Blanford, B. J. Melde, B. J. S.
Johnson, A. Stein, Chem. Mater. 2001, 13, 1074 – 1081; h) M.
Bonchio, M. Carraro, G. Scorrano, A. Bagno, Adv. Synth. Catal.
Received: July 21, 2005
Revised: December 22, 2005
Published online: February 17, 2006
2004, 346, 648 – 654.
[
9] J. Fuchs, R. Palm, Z. Naturforsch. B 1984, 39, 757 – 762.
[
10] Formation of the W20 clusters 2 and 3 presented herein suggests
Keywords: homogeneous catalysis · lactones · oxidation ·
polyoxometalates · tungsten
that larger POMs are likely formed through condensation of
.
lacunary POMs. For example, Wells–Dawson-type clusters
nꢀ
[
X M O ] can be regarded as dimers of trivacant Keggin-
2
18 62
nꢀ
type POMs [XM O ] , and the acidification of K [a-SiW O ]
9
34
10
9
34
gives K [{K(H O) } {K(H O) }(Si W O )], the structure of
1
3
2
3
2
2
2
2
18 66
which can be described as open Wells–Dawson type: a) N.
Laronze, J. Marrot, G. HervØ, Chem. Commun. 2003, 2360 –
[
1] a) C. L. Hill, C. Chrisina, M. P. McCartha, Coord. Chem. Rev.
995, 143, 407 – 453; b) T. Okuhara, N. Mizuno, M. Misono, Adv.
Catal. 1996, 41, 113 – 252; c) thematic issue on polyoxometalates
Ed.: C. L. Hill): Chem. Rev. 1998, 98, 1– 390; d) R. Neumann,
1
2361; b) N. Leclerc-Laronze, J. Marrot, G. HervØ, Inorg. Chem.
2005, 44, 1275 – 1281.
(
[
11] A Baeyer–Villiger oxidation step is suggested to be involved in
Prog. Inorg. Chem. 1998, 47, 317 – 370; e) Polyoxometalate
Chemistry: From Topology via Self-Assembly to Applications
2
the oxidation of cyclohexanone to adipic acid with H O2
catalyzed by H WO , although the corresponding lactone
(
Eds.: M. T. Pope, A. Müller), Kluwer, Dordrecht, 2001;
f) Polyoxometalate Chemistry for Nano-Composite Design
Eds.: T. Yamase, M. T. Pope), Kluwer, Dordrecht, 2002;
2
4
intermediate has not been detected: a) Y. Usui, K. Sato, Green
Chem. 2003, 5, 373 – 375. See also the following paper reporting
the oxidative transformation of cyclohexene to adipic acid: b) K.
Sato, M. Aoki, R. Noyori, Science 1998, 281, 1646 – 1647.
12] In the present system, a peroxide adduct of 2 could not be
detected.
(
g) I. V. Kozhevnikov, Catalysis by Polyoxometalates, Wiley,
Chichester, UK, 2002; h) “Polyoxometalates: Reactivity”: C. L.
Hill in Comprehensive Coordination Chemistry II: Transition
Metal Groups 3–6, Vol. 4 (Ed.: A. G. Wedd), Elsevier, New
York, 2004, chap. 4.11, pp. 679 – 759.
[
[
2+
13] The platinum diphosphane complex [Pt(m-OH)(dppb)]
dppb = 1,4-bis(diphenylphosphanyl)butane) catalyzes the oxi-
(
[
2] a) M. T. Pope, Heteropoly and Isopoly Oxometalates, Springer,
Berlin, 1983; b) M. T. Pope, A. Müller, Angew. Chem. 1991, 103,
dation of acyclic methyl ketones, but the activity for the
oxidation of acetophenone is very low in comparison with
those for aliphatic ketones: R. Gavagnin, M. Cataldo, F. Pinna,
G. Strukul, Organometallics 1998, 17, 661– 667.
56 – 70; Angew. Chem. Int. Ed. Engl. 1991, 30, 34 – 48; c) “Poly-
oxo Anions: Synthesis and Structure”: M. T. Pope in Compre-
hensive Coordination Chemistry II: Transition Metal Groups 3–6,
Vol. 4 (Ed.: A. G. Wedd), Elsevier, New York, 2004, chap. 4.10,
pp. 635 – 678.
[14] The oxidation of aliphatic and aromatic aldehydes with H O
2 2
3
ꢀ
mediated by the tungsten peroxo complex [PO {W(O)(O ) } ]
4 2 2 4
[
3] a) J. Canny, A. TØzØ, R. Thouvenot, G. HervØ, Inorg. Chem.
has been suggested to proceed by a Baeyer–Villiger-type
mechanism, although the products are the corresponding
carboxylic acids, and formate esters and/or hydrolysis products
(i.e., alcohols and phenols) have not been detected: C. Ventur-
ello, M. Gambaro, J. Org. Chem. 1991, 56, 5924 – 5931.
1986, 25, 2114 – 2119; b) A. TØzØ, G. HervØ, Inorg. Synth. 1990,
27, 85 – 96.
[
4] a) J. Canny, R. Thouvenot, A. TØzØ, G. HervØ, M. Leparulo-
Loftus, M. T. Pope, Inorg. Chem. 1991, 30, 976 – 981; b) K.
Wassermann, H.-J. Lunk, R. Palm, J. Fuchs, N. Steinfeldt, R.
Stösser, M. T. Pope, Inorg. Chem. 1996, 35, 3273 – 3279; c) X.-Y.
Zhang, C. J. OꢀConnor, G. B. Jameson, M. T. Pope, Inorg. Chem.
[15] For peracid-mediated Baeyer–Villiger oxidation of 2-methylated
cycloalkanones, oxygen insertion between the carbonyl group
and the more highly substituted neighboring carbon atom is
[
6]
1996, 35, 30 – 34; d) C. Nozaki, I. Kiyoto, Y. Minai, M. Misono, N.
favorable,
whereas the regioselectivity for (Lewis and
Mizuno, Inorg. Chem. 1999, 38, 5724 – 5729.
Brønsted) acid-catalyzed oxygenation with H O is similar to
2
2
Angew. Chem. Int. Ed. 2006, 45, 1956 –1960
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1959