G. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 1571–1574
1573
Table 2
to about 2 mL in vacuo, and cooled to ꢂ30 °C to give pale blue crys-
tals of 1 (101 mg, 30% yield).
Selected bond lengths (Å) and angles (°) in 1.
Elemental Anal. Calc. for C112H252ClNaNd4O48Si28: C, 35.50; H,
6.70; Nd, 15.23. Found: C, 35.64; H, 6.68; Nd, 15.18%.
Nd–O1
Nd–O6
Nd–O6ii
Nd–O10
Nd–O10i
Nd–Cl1
O6i–Nd–O6
O10ii–Nd–O6
O10–Nd–O6
O1–Nd–Cl1
O6i–Nd–Cl1
O10ii–Nd–Cl1
O10-Nd–Cl1
O6–Nd–Cl1
O1–Nd–O4
2.171(8)
2.508(9)
2.345(9)
2.405(9)
2.358(9)
2.5742(7)
72.8(4)
136.7(3)
90.1(4)
160.3(3)
71.3(3)
O6i–Nd–O4
O10ii–Nd–O4
O10–Nd–O4
O6–Nd–O4
95.3(3)
167.8(3)
105.6(3)
55.5(3)
124.07(18)
89.25(3)
178.61(4)
178.61(4)
90.77(3)
89.25(3)
98.0(4)
IR data (nujol, m
, cmꢂ1): 2954 s, 2928 m, 2905 m, 2871 m, 1465
m, 1401 w, 1383 w, 1366 w, 1228 w, 1080 s, 992 m, 925 m, 835 m,
Cl1–Nd–O4
739 m, 580 w, 506 w, 430 w.
Nd–Cl1–Ndii
Ndii–Cl1–Ndi
Nd–Cl1–Ndiii
Ndii–Cl1–Ndiii
Ndi–Cl1–Ndiii
Ndi–O6–Nd
Ndi–O6–Nai
Nd–O6–Nai
Ndii-O10–Nd
3
1H NMR (C6D6, d, ppm): 2.10 (m, JHH = 6.8 Hz, –CH2CH(CH3)2);
3
3
1.10 (d, JHH = 6.4 Hz, –CH2CH(CH3)2); 0.86 (d, JHH = 6.8 Hz,
–CH2CH(CH3)2). Other signals are unable to be assigned due to
the paramagnetic property of the Nd complex.
67.9(2)
67.3(2)
68.9(2)
75.6(3)
88.7(4)
86.7(4)
98.8(4)
4.3. Polymerization procedure
Trimethylsilane chloride (6.9 lL, 0.054 mmol) and 1 (102 mg,
0.027 mmol) in 2 ml toluene were added to a 20 mL ampule. After
stirring for 0.5 h, AlEt3 (0.09 mL, 0.677 mmol) was added. The cat-
alyst solution was aged for 1 h at 60 °C, and then isoprene (4 mL,
40 mmol) was added. After 18.5 h, the polymerization was
quenched with 5% HCl ethanol solution containing 1% 2,6-di-tert-
butyl-4-methyl phenol. The resulting polymer was isolated,
washed with ethanol, and dried under vacuum.
catalytic system. With 0.027 mmol 1, 0.677 mmol AlEt3,
0.054 mmol Me3SiCl and 40 mmol isoprene in 2 mL of toluene,
the polymerization proceeded and gave a cis-1,4 polyisoprene with
60% yield in 18.5 h. The polymer has high cis-1,4 content (92%) and
8% 3,4-content. The molecular weight of the polymer is 3.35 ꢃ 103,
and the polydispersity is 1.99.
4.4. X-ray crystallography for 1
3. Conclusions
Suitable single crystals of 1 were sealed in thin-walled glass
capillaries, and data collection was performed at 20 °C on a Bruker
In conclusion, a new tetrameric neodymium-silsesquioxane
cage complex {[(i-C4H9)7(Si7O12)Nd]4NaCl} (1) was synthesized
and characterized. The four Nd-POSS units of 1 are linked by multi-
ple Nd–O–Nd and Nd–Cl–Nd bonding. The Nd–O–Si bonding
interactions in complex 1 can be used to mimic those in the sil-
ica-supported rare-earth metal catalysts.
SMART diffractometer with graphite-monochromated Mo Ka radi-
ation (k = 0.71073 Å). The SMART program package was used to
determine the unit-cell parameters. The absorption correction
was applied using SADABS. The structure was solved by direct meth-
ods. As isobutyl groups are disordered in the crystal structure, their
geometry parameters were constrained in the refinement process.
The crystal structure was refined isotropically for isobutyl-C atoms
and anisotropically for the other non-H atoms. Hydrogen atoms
were placed at calculated positions and were included in the struc-
ture calculation without further refinement of the parameters. A
PLATON calculation indicates that the crystal structure contains
solvent accessible voids of 1160 Å3 between disordered isobutyl
groups of the adjacent molecules, but no solvent molecules could
be located in the difference Fourier map, resulting the larger R fac-
tor and smaller Dcalc value.
4. Experimental
4.1. General
All operations were carried out under an atmosphere of argon
using Schlenk techniques. Anhydrous NdCl3 was prepared from
Nd2O3 and HCl according to the standard procedure [24]. NaOiPr
in benzene/iPrOH was synthesized according to the literature pro-
cedure [25]. (i-C4H9)7(Si7O9)(OH)3 was purchased from Aldrich and
used without further purification. Toluene and hexane were dis-
tilled from Na-benzophenone ketyl. The elemental analysis was
performed on a Flash EA1112, and the content of rare-earth metal
was measured by EDTA-titration method. 1H NMR spectra were re-
corded on a Bruker Avance DMX 400 MHz spectrometer in d6-ben-
zene at room temperature, and the chemical shifts were reported
in d units with references to the residual solvent resonance of
the deuterated solvent. IR spectra were recorded on a Bruker Fou-
rier transforminfrared (FT-IR) spectrometer.
Acknowledgments
This work was supported by the National Natural Science Foun-
dation (Grant Nos. 20674071 and 20434020) and the Special Funds
for Major State Basic Research Projects (No. 2005CB623802).
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NaOiPr (97 mg, 1.18 mmol) in 4 mL of hot benzene/iPrOH(v/
v = 1:1) was added into a refluxing iPrOH solution of NdCl3
(95 mg, 0.38 mmol, in 4 mL of iPrOH), the reaction mixture was re-
fluxed overnight. The precipitate was removed by centrifugation.
The clear blue solution was evaporated in vacuo to give pale blue
residue. The above residue was extracted by 7 mL of toluene. [(i-
C4H9)7(Si7O9)(OH)3] (292 mg, 0.37 mmol) was added to the toluene
extract, and the reaction mixture was stirred at 70 °C for 12 h. The
solvent was removed in vacuo, and the pale blue residue was ex-
tracted by 7 mL of hexane. The hexane extract was concentrated