Novel Binuclear Samarium(II) Complex
Organometallics, Vol. 23, No. 6, 2004 1367
pressure. The residue was dissolved in hexane to give a purple-
brown solution, and the volume of the solution was reduced
under vacuum to precipitate purple powder. The precipitate
was collected by decanting the solution and was recrystallized
from a hot hexane solution to afford 2 as dark purple needle
to give a white powder, which was then dissolved in THF. After
reduction of solution volume under reduced pressure, ether
was slowly added to precipitate 7 as colorless blocks (1.70 g,
67%). The crystals were dried for 8 h under reduced pressure,
but the lattice solvent of THF could not be removed.15 1H NMR
(C6D6, 22 °C): δ 8.33 (br s, 18 H, o-Ph), 7.23 (br s, 27 H, m,p-
Ph), 2.27 (br s, 16 H, THF), 0.58 (br s, 16 H, THF). Anal. Calcd
for C70H77O7Si3Sm: C, 66.46; H, 6.14. Found: C, 65.93; H, 6.18.
[Sm {OSi(OtBu )3}2{µ-OSi(OtBu )3}]2 (8). Addition of a tolu-
ene solution (5 mL) of (tBuO)3SiOH (793 mg, 3 mmol) to a pale
yellow toluene solution (10 mL) of Sm(N(SiMe3)2)3 (632 mg, 1
mmol) gave a colorless reaction mixture immediately, which
was stirred at room temperature for 2 h. The solvent was
removed under reduced pressure. The residue was washed
with hexane and dried to give 8 as a white powder (847 mg,
90%). Single crystals of 8 for X-ray structural analysis were
obtained by slow evaporation of a toluene solution in the
glovebox for 2 weeks. 1H NMR (C6D6, 22 °C): δ 2.24, 1.45, 1.30
(the integrations were dependent on concentration). Anal.
Calcd for C36H81O12Si3Sm: C, 45.97; H, 8.68. Found: C, 46.07;
H, 8.88.
1
crystals (283 mg, 0.31 mmol, 31% yield based on C5Me5). H
NMR (C6D6, 22 °C): δ 7.99 (s, 15 H, C5Me5), 4.80 (br s, 36 H,
Me), 3.20 (br s, 27 H, tBu). The connection of the molecule was
determined by an X-ray analysis, but further refinement was
not allowed because of poor quality of the crystal. Anal. Calcd
for C34H78O6N6SiP2Sm: C, 45.00; H, 8.66; N, 9.26. Found: C,
44.33; H, 8.73; N, 8.98. The lower value found for carbon might
be due to possible formation of incombustible carbide species.20
[(C 5 Me 5 )S m {µ-O S i(O t B u )3 }2 (µ,η1 :η2 -N 2 P h 2 )S m O S i-
(OtBu )3] (3). Azobenzene (364 mg, 2 mmol) in toluene (2 mL)
was added to a green solution of 1 (2.452 g, 2 mmol) in toluene
(30 mL). The solution color changed from green to red brown
immediately. After the solution was stirred at room temper-
ature for 30 min, the solvent was concentrated and was then
left to stand at room temperature for 2 weeks to afford 3 as
red-brown needle crystals (1.80 g, 64%). 1H NMR (C6D6, 22
°C): δ 4.53 (br s, 10 H, Ph), 2.92 (br s, 15 H, C5Me5), 2.63 (s,
27 H, tBu), -1.55 (br s, 54 H, tBu). Anal. Calcd for C58H106N2O12-
Si3Sm2: C, 49.46; H, 7.59; N, 1.99. Found: C, 48.93; H, 7.63;
N, 1.79.
[{(t B u O )3 S i O }3 G d I I I (µ,η5 :η5 -C 5 M e 5 )S m I I {µ-O S i (O -
tBu )3}3Sm II] (9). Starting from 6 (328 mg, 0.3 mmol), complex
9 was obtained as a green powder (574 mg, 88%) in a manner
analogous to that described for the synthesis of 4 (method B).
Dark green crystals of 9 were obtained from a hot benzene
[ {( t B u O ) 3 S i O }3 S m I I I ( µ,η5 :η5 -C 5 M e 5 ) S m I I {µ-O S i -
(OtBu )3}3Sm II] (4). Method A: To a toluene solution (5 mL)
solution. An informative H NMR spectrum was not obtained
1
t
of 1 (245 mg, 0.2 mmol) was added ArOH (Ar ) C6H2 Bu2-2,6-
for 9, because of the influence of the paramagnetic Gd(III) ion.
Anal. Calcd for C82H177O24Si6Sm2Gd: C, 45.31; H, 8.21.
Found: C, 44.41; H, 7.96. The lower value found for carbon
might be due to possible formation of incombustible carbide
species.20
[(P h 3SiO)3Sm I I I (µ,η5:η5-C5Me 5)Sm I I {µ-OSi(Ot Bu )3}3-
Sm II] (10). A toluene solution (5 mL) of 1 (245 mg, 0.2 mmol)
was added to a toluene solution (5 mL) of 7 (253 mg, 0.2 mmol)
at room temperature. The solution color changed from green
to brown immediately. After the mixture was stirred for 2 h,
the solvent was removed under reduced pressure. The residue
was washed with hexane and dried to give 10 (344 mg, 78%
yield). Dark brown blocks of 10 suitable for X-ray analysis were
obtained by recrystallization from a concentrated hot toluene
solution. 1H NMR (C6D6, 22 °C): δ 14.2 (s, 15 H, C5Me5), 6.65-
7.35 (m, 45 H, Ph), 2.1 (br s, 81 H, tBu). Anal. Calcd for
Me-4) (44 mg, 0.2 mmol) in 5 mL of toluene. The mixture was
stirred at room temperature for 8 h. Reduction of the solution
volume under reduced pressure gave green precipitates, which
were collected and recrystallized from a hot toluene solution
to give 4 as green blocks (65 mg, 23% yield based on Sm). The
reaction of 1 with phenylacetylene also gave 4 similarly.
Method B: A toluene solution (5 mL) of 1 (245 mg, 0.2 mmol)
was added to a toluene solution (5 mL) of 5 (217 mg, 0.2 mmol)
at room temperature. After the mixture was stirred for 2 h,
the solvent was removed under reduced pressure. The residue
was washed with hexane and dried to give 4 (370 mg, 85%
yield). The reaction of 1 (245 mg, 0.2 mmol) with 8 (188 mg,
0.1 mmol) also gave 4 (355 mg, 82%). Dark green blocks of 4
suitable for X-ray analysis were obtained by recrystallization
1
from a concentrated hot toluene solution. H NMR (C6D6, 22
t
°C): δ 15.72 (s, 15 H, C5Me5), 3.1 (br s, 81 H, Bu), 1.21 (s, 81
C
100H141O15Si6Sm3: C, 54.53; H, 6.45. Found: C, 52.10; H, 6.35.
t
H, Bu). Anal. Calcd for C82H177O24Si6Sm3: C, 45.45; H, 8.23.
The lower value found for carbon might be due to possible
formation of incombustible carbide species.20
Found: C, 44.68; H, 8.25. The lower value found for carbon
might be due to possible formation of incombustible carbide
species.20
[Sm I I {µ-OSi(Ot Bu )3}3Sm I I (µ,η5:η5-C5Me 5)Sm I I {µ-OSi-
(OtBu )3}3Sm II][Sm II{N(SiMe3)2}3] (11). To a toluene solution
(5 mL) of Sm{N(SiMe3)2}2(thf)2 (123 mg, 0.2 mmol) was added
a toluene solution (5 mL) of 1 (245 mg, 0.2 mmol). The brown
mixture was stirred at room temperature for 24 h and filtered
through a frit. The solvent was removed under reduced
pressure to give brown powders, which after recrystallization
from toluene yielded 11 (ca. 48 mg, 16%) as brown crystals
together with some green powders (possibly [(C5Me5)Sm-
{N(SiMe3)2}]. A complete separation of 11 and the green
powders was difficult, but single crystals of 11 suitable for
X-ray analysis could be selected. 1H NMR (C6D6, 22 °C): δ 9.8
(br s, 15 H, C5Me5), 3.0 (s, 36 H, SiMe3), 0.3 (s, 18 H, SiMe3),
Sm {OSi(OtBu )3}3(th f)2 (5). A mixture of Sm{N(SiMe3)2}3
(1.26 g, 2 mmol) and (tBuO)3SiOH (1.59 g, 6 mmol) in 20 mL
of THF was stirred at room temperature for 10 h. The volatiles
were removed under reduced pressure to give a white powder,
which was recrystallized from hot hexane to give 5 as colorless
blocks (1.63 g, 75%). Complex 5 could also be obtained in
quantitative yield by dissolving 8 in THF and drying under
1
reduced pressure. H NMR (C6D6, 22 °C): δ 1.87 (br s, 81 H,
1
tBu), 0.94 (br s, 8 H, THF), 0.04 (br s, 8 H, THF). The H NMR
spectrum seemed to be concentration dependent. Anal. Calcd
for C44H97O14Si3Sm: C, 48.71; H, 9.01. Found: C, 48.66; H,
8.91.
t
1.5 (br 162 H, Bu). Anal. Calcd for C100H231N3O24Si12Sm5: C,
Gd {OSi(OtBu )3}3(th f)2 (6). Starting from Gd{N(SiMe3)2}3
(638 mg, 1 mmol), complex 6 was obtained as a white powder
(884 mg, 81%) in a manner analogous to that described for
40.73; H, 7.90; N, 1.43. Found: C, 39.10; H, 7.64; N, 1.31. The
lower value found for carbon might be due to possible forma-
tion of incombustible carbide species.20
1
the synthesis of 5. An informative H NMR spectrum was not
X-r a y Cr ysta llogr a p h ic Stu dies. Crystals for X-ray analy-
ses were obtained as described in the preparations. The
crystals were manipulated in the glovebox under a microscope
mounted on the glovebox window and sealed in thin-walled
glass capillaries. Data collections of 4 and 8 were performed
on a Rigaku R-AXISII diffractometer with graphite-monochro-
mated Mo KR radiation (λ ) 0.71070 Å), and the structures
were solved by using the teXsan software package. Data
obtained for 6, because of the influence of the paramagnetic
Gd(III) ion. Anal. Calcd for C44H97O14Si3Gd: C, 48.41; H, 8.96.
Found: C, 48.44; H, 8.96.
Sm (OSiP h 3)3(th f)3‚(th f) (7). A mixture of Sm{N(SiMe3)2}3
(1.26 g, 2 mmol) and Ph3SiOH (1.66 g, 6 mmol) in 20 mL of
THF was stirred at room temperature for 5 h. The solvent and
hexamethyldisilazane were removed under reduced pressure
Nishiura, Masayoshi
