Inorganic Chemistry
Article
2 +
Nacalai, Fluka, Acros, or KANTO (reagent grade) and purified prior to
use (if necessary).
3 9 2 1 [ T B A
H N d ( S i W
O
) ]
2
,
3 8 0 0
1 1
2
1 0
3 6
[TBA10H2Nd2(SiW10O36)2]2+. IR (KBr pellet, cm−1): 2960, 2932,
2872, 1634, 1600, 1517, 1483, 1382, 1263, 1153, 1106, 1066, 996, 953,
871, 751, 554, 461, 360, 309.
X-ray Crystallography. The diffraction measurements were made
on a Rigaku MicroMax-007 Saturn 724 CCD detector with graphite-
monochromated Mo Kα radiation (λ = 0.710 69 Å) at −120 or −150
°C. The data were collected and processed using CrystalClear22 for
Windows software and HKL200023 for Linux software. Neutral
scattering factors were obtained from the standard source. In the
reduction of data, Lorentz and polarization corrections were made.
The structural analyses were performed using CrystalStructure,24
WinGX,25 and Yadokari-XG.26 All structures were solved by SHELXS-
97 (direct methods) and refined by SHELXH-97.27 The metal atoms
(Si, W, and RE), oxygen atoms in the POM frameworks, and oxygen
and carbon atoms of coordinated acetone molecules were refined
anisotropically. CCDC-869962 (TBA6Nd-POM), CCDC-869963
(TBA6Eu-POM), CCDC-869964 (TBA6Gd-POM), CCDC-869965
(TBA6Tb-POM), and CCDC-869966 (TBA6Dy-POM) contain the
supplementary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic Data
Information.
Synthesis of TBA6Y-POM. TBA6Y-POM was synthesized
according to the previously reported procedure.10 To an acetone
solution of SiW10 (1.0 g, 0.29 mmol, 20 mL), Y(acac)3·11H2O (170
mg, 0.29 mmol, 1 equiv with respect to SiW10), and HNO3 (1 M, 0.29
mL, 1 equiv. with respect to SiW10) were added, and the resulting
solution was stirred for 15 min at room temperature (ca. 20 °C).
Then, the white precipitate formed was filtered off, washed with
acetone, and air-dried to afford 810 mg of TBA6Y-POM (85% yield
based on SiW10). The colorless crystals of TBA6Y-POM suitable for
the X-ray crystallographic analysis were obtained by recrystallization
from a mixed solvent of acetone and acetonitrile (4:1, v/v/v). Elem.
Anal. Calcd (%) for C105H250Si2N6O81W20Y2 (TBA6H4[{Y-
(H2O)2(CH3COCH3)}2(SiW10O36)2]·(CH3COCH3)·2H2O): C,
18.66; H, 3.78; N, 1.27; Si, 0.83; W, 54.22; Y, 2.62. Found: C,
18.54; H, 3.70; N, 1.24; Si 0.83; W, 54.04; Y, 2.61. Positive-ion MS
(CSI, CH3CN): m/z 6764 [TBA7H4Y2(SiW10O36)2]+, 3503
[TBA8H4Y2(SiW10O36)2]2+. IR (KBr pellet, cm−1): 1710, 1701, 1697,
1623, 1484, 1466, 1420, 1383, 1363,1282, 1242, 1222, 1152, 1105,
999, 962, 891, 818, 758, 553, 511, 460, 384, 362, 305.
Synthesis of TBA6Nd-POM. To an acetone solution of SiW10
(200 mg, 0.0582 mmol, 4 mL), Nd(acac)3 (25.7 mg, 0.0582 mmol, 1
equiv with respect to SiW10) and HNO3 (1 M, 0.058 mL, 1 equiv with
respect to SiW10) were added, and the resulting solution was stirred
for 15 min at room temperature (ca. 20 °C). Then, the white
precipitate formed was filtered off, washed with acetone, and air-dried
to afford 167 mg of TBA6Nd-POM (84% yield based on SiW10). The
colorless crystals of TBA6Nd-POM suitable for the X-ray crystallo-
graphic analysis were obtained by recrystallization from a mixed
solvent of acetone and acetonitrile (4:1, v/v). Elem. Anal. Calcd (%)
f o r C 1 0 2 H 2 4 4 S i 2 N 6 O 8 0 W 2 0 N d 2 ( T B A 6 H 4 [ { N d -
(H2O)2(CH3COCH3)}2(SiW10O36)2]·2H2O): C 17.87, H 3.59, N
1.23, Si 0.82, Nd 4.21, W 53.63. Found: C 17.82, H 3.70, N 1.31, Si
0.84, Nd 4.50, W 53.92. Positive-ion MS (CSI, acetone): m/z 6874
[TBA7H4Nd2(SiW10O36)2]+, 3559 [TBA8H4Nd2(SiW10O36)2]2+. IR
(KBr pellet, cm−1): 2961, 2933, 2873, 1685, 1627, 1484, 1470,
1382, 1243, 1152, 1105, 998, 962, 874, 757, 554, 461, 381, 361, 311.
Synthesis of TBA8Nd-POM. To an acetone solution of SiW10
(1.50 g, 0.437 mmol, 30 mL), Nd(acac)3 (0.193 g, 0.437 mmol, 1
equiv with respect to SiW10) was added, and the resulting solution
was stirred for 15 min at room temperature (ca. 20 °C). Then, the pale
blue precipitate formed was filtered off, washed with diethyl ether, and
air-dried to afford 1.10 g of TBA8Nd-POM in 70% yield (0.152
mmol). The pale blue crystals of TBA8Nd-POM were obtained by
recrystallization from a mixed solvent of acetone, acetonitrile, and
diethyl ether (1:2:1, v/v). Elem. Anal. Calcd (%) for
C128H304Si2N8O79Nd2W20 (TBA8H2[Nd2(SiW10O36)2]·7H2O): C,
21.23; H, 4.23; N, 1.55; Si, 0.78; Nd, 3.98; W, 50.78. Found: C,
21.18; H, 4.37; N, 1.51; Si 0.80; Nd, 4.03; W, 55.44. Positive-ion MS
(CSI, 1,2-dichloroethane): m/z 7357 [TBA9H2Nd2(SiW10O36)2]+,
Synthesis of TBA6Eu-POM. TBA6Eu-POM was synthesized via
the same procedure as that for TBA6Nd-POM except that Eu(acac)3
was used (colorless crystals, 161 mg, 80% yield based on SiW10).
Elem. Anal. Calcd (%) for C102H244Si2N6O80W20Eu2 (TBA6H4[{Eu-
(H2O)2(CH3COCH3)}2(SiW10O36)2]·2H2O): C, 17.83; H, 3.58; N,
1.22; Si, 0.82; Eu, 4.42; W, 53.50. Found: C, 17.68; H, 3.67; N, 1.19;
Si, 0.84; Eu, 4.54; W, 53.69. Positive-ion MS (CSI, CH3CN): m/z
6888 [TBA7H4Eu2(SiW10O36)2]+, 3687 [TBA9H3Eu2(SiW10O36)2]2+,
3567 [TBA8H4Eu2(SiW10O36)2]2+. IR (KBr pellet, cm−1): 2962, 2932,
2874, 1708, 1688, 1627, 1484, 1470, 1423, 1381, 1360, 1243, 1223,
1151, 1105, 998, 960, 876, 820, 759, 668, 629, 555, 512, 459.
Synthesis of TBA6Gd-POM. TBA6Gd-POM was synthesized via
the same procedure as that for TBA6Nd-POM except that Gd(acac)3
was used (colorless crystals, 162 mg, 81% yield based on SiW10).
Elem. Anal. Calcd (%) for C105H250Si2N6O81W20Gd2 (TBA6H4[{Gd-
(H2O)2(CH3COCH3)}2(SiW10O36)2]·(CH3COCH3)·2H2O): C,
18.17; H, 3.63; N, 1.21; Si, 0.81; W, 52.98; Gd, 4.53. Found: C,
18.19; H, 3.61; N, 1.30; Si, 0.82; W, 52.67; Gd, 4.71. Positive-ion MS
(CSI, acetone): m/z 6900 [TBA7H4Gd2(SiW10O36)2] +, 3572
[TBA8H4Gd2(SiW10O36)2]2+. IR (KBr pellet, cm−1): 2962, 2935,
2874, 1710, 1691, 1625, 1484, 1420, 1382, 1362, 1241, 1221, 1152,
1106, 998, 962, 876, 760, 553, 461.
Synthesis of TBA6Tb-POM. TBA6Tb-POM was synthesized via
the same procedure as that for TBA6Nd-POM except that Tb(acac)3
was used (colorless crystals, 170 mg, 81% yield based on SiW10).
Elem. Anal. Calcd (%) for C102H244Si2N6O80W20Tb2 (TBA6H4[{Tb-
(H2O)2(CH3COCH3)}2(SiW10O36)2]·2H2O): C, 17.79; H, 3.57; N,
1.22; Si, 0.82; W, 53.40; Tb, 4.62. Found: C, 17.96; H, 3.69; N, 1.30;
Si, 0.83; W, 53.84; Tb, 4.98. Positive-ion MS (CSI, CH3CN): m/z
3573 [TBA8H4Tb2(SiW10O36)2]+. IR (KBr pellet, cm−1): 2962, 2937,
2873, 1710, 1692, 1627, 1484, 1468, 1419, 1382, 1361, 1242, 1221,
1151, 1105, 999, 962, 887, 817, 759, 668, 627, 554, 551, 461.
Synthesis of TBA6Dy-POM. TBA6Dy-POM was synthesized via
the same procedure as that for TBA6Nd-POM except that Dy(acac)3
was used (colorless crystals, 143 mg, 71% yield based on SiW10).
Elem. Anal. Calcd (%) for C102H244Si2N6O80W20Dy2 (TBA6H4[{Dy-
(H2O)2(CH3COCH3)}2(SiW10O36)2]·2H2O): C, 17.77; H, 3.57; N,
1.22; Si, 0.82; W, 53.34; Dy, 4.71. Found: C, 17.86; H, 3.71; N, 1.33;
Si, 0.83; W, 53.67; Dy, 4.78. Positive-ion MS (CSI, CH3CN): m/z
3576 [TBA8H4Dy2(SiW10O36)2]2+. IR (KBr pellet, cm−1): 2961, 2932,
2873, 1710, 1693, 1634, 1484, 1466, 1419, 1383, 1361, 1242, 1223,
1151, 1106, 999, 962, 886, 817, 758, 670, 627, 552, 511, 461.
Cyanosilylation. The detailed reaction conditions are shown in
the footnotes of the tables. A typical procedure for cyanosilylation of
carbonyl compounds is as follows: Into a Pyrex-glass screw cap vial
were successively placed TBA8Nd-POM (0.5 mol %), 1a (0.25 mmol),
and acetonitrile (1.0 mL). A Teflon-coated magnetic stir bar was
added, and the reaction was initiated by addition of (TMS)CN (0.375
mmol). The reaction mixture was vigorously stirred (800 rpm) at 30
°C in 1 atm of air. The conversion of 1a and the product yield were
periodically determined by GC analysis. After the reaction was
completed (>99% conversion of 1a for 7 min), acetonitrile was
evaporated, followed by addition of n-hexane to precipitate the
catalyst. The catalyst was removed by filtration (17 mg, 93% catalyst
recovery), followed by column chromatography on silica gel (eluent:
n-hexane), giving the corresponding cyanohydrin trimethylsilyl ether
2a (0.0598 g, 96% isolated yield). All products (cyanohydrin
trimethylsilyl ethers) were confirmed by comparison of their GC
retention times, GC-mass spectra, and/or H and 13C NMR spectra
1
with those of authentic data. The retrieved catalyst was washed with n-
hexane (ca. 50 mL), and then air-dried prior to being used for the
reuse experiment. The IR spectrum of the retrieved TBA8Nd-POM
was intrinsically identical to that of as-prepared TBA8Nd-POM
(Figure S9). When the cyanosilylation of 1a was carried out with
the retrieved catalyst under the conditions in Table 4, 2a was obtained
in 98% yield.
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dx.doi.org/10.1021/ic3008365 | Inorg. Chem. 2012, 51, 6953−6961