t
germanium() complex [Ph3Ge(SC6H4 Bu-4)], d(Ge–S)
=
(0.450 g, 2.39 mmol) in benzene (5 cm3). The solution instantly
2.229(2) Å.46 The environment about the germanium atom is
approximately tetrahedral, with an average S–Ge–S bond angle
of 110.76Њ.
became colorless and was stirred for 12 h. The volatiles were
removed in vacuo to yield a white solid which was recrystallized
from a warm benzene–hexane (50:50 v/v) solution to yield
0.37 g (58%) of 3 as colorless crystals. Anal. Calc. for
C36H26GeO2 (3): C, 76.77; H, 4.65. Found: C, 76.62; H, 4.87%.
1H NMR (C6D6): δ 7.41 (m, 8 H, 2,6-diphenyl groups), 7.17 (d,
4 H, meta-Ph2C6H3), 7.00 (m, 12 H, 2,6-diphenyl groups), 6.86
(t, 2 H, para-Ph2C6H3).
Conclusions
Germanium aryloxide complexes have been prepared by the
protonolysis reaction between Ge[N(SiMe3)2]2 and phenols
ArOH, and the nature of the incoming phenoxide ligand dic-
tates the nature of the product obtained. Less bulky ligands
give rise to dimeric structures containing bridging phenoxide
ligands and pyramidalized germanium atoms, while more
sterically encumbering ligands result in monomeric complexes.
The complex [Ge(OC6HPh4-2,3,5,6)2] (4) undergoes reactions
typical of germylene complexes, including oxidative addition to
α-diketones and alkyl halides. The new arylthiolato germane
Synthesis of [Ge(OC6HPh4-2,3,5,6)2] (4)
A suspension of 2,3,5,6-tetraphenylphenol (3.10 g, 7.78 mmol)
in benzene (20 cm3) was added to a solution of Ge[N(SiMe3)2]2
(1.32 g, 3.35 mmol) in benzene (5 cm3). The solution was gently
heated until all of the material dissolved, upon which the
orange color faded. The mixture was allowed to cool to room
temperature and was stirred for 12 h resulting in the formation
of a white precipitate. The volatiles were removed in vacuo and
the resulting solid was washed with 3 × 20 cm3 of benzene
followed by recrystallization from 20 cm3 of hot benzene to
yield 2.43 g (84%) of 4 as colorless crystals. Anal. Calc. for
C66H48GeO2 (4ؒC6H6): C, 83.82; H, 5.12. Found: C, 84.04; H,
i
species [HGe(SC6H2 Pr3-2,4,6)3] (8) has been prepared from
Ge[N(SiMe3)2]2, and presumably forms by a two-step process
i
involving metathesis to yield [Ge(SC6H2 Pr3-2,4,6)2] followed
by insertion of this materials into the S–H bond of HSC6-
i
H2 Pr3-2,4,6.
1
5.37%. H NMR: δ 7.31–7.23 (m, 15 H, aromatics), 7.02–6.90
Experimental
(m, 27 H, aromatics) ppm.
General considerations
Synthesis of [Ge(OC6H2Me3-2,4,6)(O2C2Ph2)(O2C2HPh2)] (5)
All manipulations were carried out using standard Schlenk,
syringe and glovebox techniques.47 Solvents were purified using
an Innovative Technologies solvent purification system. 1H
NMR spectra were recorded at 300 MHz using a Varian
Inova-300 or at 500 MHz using a Bruker DRX-500 spectro-
meter. Elemental analyses were carried out in-house at Purdue
University. The bisamide Ge[N(SiMe3)2]2 was purchased from
Gelest, Inc. or synthesized via literature methods.48–50 The com-
pounds 2,6-diphenylphenol,51 2,3,5,6-tetraphenylphenol52 and
2,4,6-triisopropylbenzenethiol53 were prepared according to
literature methods, while 2,4,6-trimethylphenol, 2,6-diisopropyl-
phenol, and iodomethane were purchased from Aldrich and
used without further purification. Benzil was purchased from
Aldrich and heated in vacuo at 100 ЊC for 12 h to remove water.
A solution of benzil (0.10 g, 0.48 mmol) in benzene (5 cm3) was
added to a suspension of 1 (0.13 g, 0.20 mmol) in benzene
(5 cm3). The resulting yellow solution gradually darkened to
orange–red with stirring over 2 h. The volatiles were removed
in vacuo and the resulting material was recrystallized from 3 cm3
of hot benzene. The solid was washed with 2 × 3 cm3 of
benzene to yield 5 as a red solid. Yield: 0.11 g (44%). Anal.
Calc. for C37H32GeO5 (5): C, 70.62; H, 5.12. Found: C, 70.80; H,
1
5.25%. H NMR: δ 7.91 (d, 2H, J = 7.2 Hz, o-(Ph)C(᎐O)),
᎐
7.68 (d, 2 H, J = 8.1 Hz, o-(Ph)C(H)(–O)), 7.57 (pseudo-d, br,
4H, o-(Ph) C O ), 7.05 (pseudo-t, 2 H, m-(Ph)C(᎐O)), 6.97–6.59
᎐
2
2
2
(aromatics, 12 H), 5.78 (s, 1 H, (Ph)C(H )(–O)), 2.65 (s, 6 H,
o-(Me)3C6H2O), 2.11 (s, 3 H, p-(Me)3C6H2O) ppm.
Synthesis of [Ge(OC6HPh4-2,3,5,6)2(O2C2Ph2)] (6)
Synthesis of [Ge(OC6H2Me3-2,4,6)2]2 (1)
A solution of benzil (0.080 g, 0.38 mmol) in benzene (15 cm3)
was added to a suspension of 4 (0.30 g, 0.35 mmol) in benzene
(10 cm3). The solution was gently heated until all material had
dissolved, after which time the solution darkened from yellow
to red. The volatiles were removed resulting in a red–brown
solid, which was recrystallized from 10 cm3 of hot benzene. The
solid was washed with 3 × 3 cm3 of benzene to yield 0.19 g
A solution of 2,4,6-trimethylphenol (0.81 g, 5.9 mmol) in
benzene (10 cm3) was added dropwise to a solution of
Ge[N(SiMe3)2]2 (1.05 g, 2.66 mmol) in benzene (10 cm3) with
stirring. The orange color of the solution faded and the mixture
was stirred for 6 h, after which time a white precipitate had
formed. The solvent was removed in vacuo and the crude
material was recrystallized from hot benzene (10 cm3) to yield
0.66 g (73%) of 1 as colorless crystals. Anal. Calc.. for C36H44-
1
(51%) of 6. H NMR: δ 7.91 (d, 4 H, o-(Ph)C2O2, J = 7.2 Hz),
7.54 (pseudo-t, 4 H, m-(Ph)C2O2), 7.32–6.81 (aromatics, 44 H).
1
Ge2O4 (1): C, 63.04; H, 6.36. Found: C, 62.98; H, 6.37%. H
NMR (25 ЊC, C6D6): δ 6.71 (s, 6 H, m-H), 2.31 (br s, 24 H,
o-CH3), 2.10 (s, 12 H, p-CH3) ppm.
Synthesis of [Ge(OC6HPh4-2,3,5,6)2(Me)(I)] (7)
Iodomethane (0.5 cm3, 8.0 mmol) was added via syringe to a
suspension of 4 (0.50 g, 0.58 mmol) in benzene (10 cm3). The
solution was heated until all of the material dissolved. After
cooling, the mixture was stirred for 12 h resulting in the form-
ation of an off-white precipitate. The volatiles were removed
in vacuo and the resulting solid was recrystallized from 3 cm3 of
hot benzene to 7 as a white powder. Yield: 0.41 g (70%). Anal.
Calc. for C61H45GeIO2: C, 72.58; H, 4.49. Found: C, 72.85; H,
Synthesis of [Ge(OC6H3iPr2-2,6)2]2 (2)
To a solution of Ge[N(SiMe3)2]2 (0.59 g, 1.5 mmol) in benzene
(5 cm3) was added a solution of 2,5-diisopropylphenol (0.58 g,
3.2 mmol) in benzene (5 cm3) dropwise with stirring. The reac-
tion became colorless and was stirred for 5 h. The volatiles were
removed in vacuo to yield a pale yellow oil, which solidified after
cooling at Ϫ15 ЊC for 2 h. Compound 2 was isolated as 0.39 g
(61%) of a pale yellow solid. Anal. Calc. for C48H68Ge2O4 (2):
C, 67.48; H, 8.02. Found: C, 67.11; H, 8.18%. 1H NMR (25 ЊC,
C6D6): δ 7.06 (d, J = 7.2 Hz, 8 H, m-H), 6.96 (t, 4 H, J = 6.9 Hz,
p-H), 3.60 (br s, 8 H), 1.16 (d, J = 6.6 Hz, 48 H).
1
4.67%. H NMR: δ 7.30–7.17 (m, 15 H, aromatics), 7.12–6.95
(m, 27 H, aromatics), Ϫ0.24 (s, 3 H) ppm.
i
Synthesis of [HGe(SC6H2 Pr3-2,4,6)3] (8)
A solution of 2,4,6-triisopropylthiophenol (0.87 g, 3.7 mmol)
in benzene (10 cm3) was added via syringe to a solution of
Ge[N(SiMe3)2]2 (0.46 g, 1.2 mmol) in benzene (5 cm3). The solu-
tion instantly changed from light orange to deep red–orange in
Synthesis of [Ge(OC6H3Ph2-2,6)2] (3)
A solution of 2,6-diphenylphenol (0.590 g, 1.14 mmol) in
benzene (10 cm3) was added to a solution of Ge[N(SiMe3)2]2
D a l t o n T r a n s . , 2 0 0 3 , 5 3 2 – 5 3 9
537