From chlorogermylenes to stable hydroxy- and siloxy-germylene-tungsten complexes

Article abstract of DOI:10.1021/om020187y

Reaction of the chlorogermylene ArGeCl [Ar = 2,6-bis((diethylamino)methyl)phenyl] with lithium amides afforded the aminogermylenes ArGeNR₂ 1 (la, R = SiMe₃; 1b, R = ⁱPr); 1a was structurally analyzed by X-ray diffraction. A protic reagent such as 2,4,6-trimethylphenol (Ar′OH) reacts with 1b, leading to the mesityloxygermylene ArGeOAr′ 2. Subsequent hydrolysis of tungsten complexes 1·W(CO)₅ gave ArGeOH·W(CO)₅,₃. 3. From 1a, ArGeOSiMe₃·W(CO)₅ (4) also was obtained. Compounds 3 and 4 are the first stable hydroxy- and siloxygermylene complexes. X-ray analysis of 3 shows an increased coordination of the side-chain nitrogen atoms to the germanium resulting from the complexation Ge→W. This complexation can also explain the significant acidity of the hydroxy group in 3, in the same range as triphenylgermanol Ph₃GeOH.

Full text of DOI:10.1021/om020187y

2940
Organometallics 2002, 21, 2940-2943
F r om Ch lor oger m ylen es to Sta ble Hyd r oxy- a n d
Siloxy-Ger m ylen e-Tu n gsten Com p lexes
Christine Bibal, Ste´phane Mazie`res, Heinz Gornitzka, and Claude Couret*
Laboratoire He´te´rochimie Fondamentale et Applique´e, UMR 5069, Universite´ Paul Sabatier,
118 Route de Narbonne, 31062 Toulouse Cedex 04, France
Received March 5, 2002
Reaction of the chlorogermylene ArGeCl [Ar ) 2,6-bis((diethylamino)methyl)phenyl] with
lithium amides afforded the aminogermylenes ArGeNR2 1 (1a , R ) SiMe3; 1b, R ) iPr); 1a
was structurally analyzed by X-ray diffraction. A protic reagent such as 2,4,6-trimethylphenol
(Ar′OH) reacts with 1b, leading to the mesityloxygermylene ArGeOAr′ 2. Subsequent
hydrolysis of tungsten complexes 1‚W(CO)5 gave ArGeOH‚W(CO)5, 3. From 1a , ArGeOSiMe3‚
W(CO)5 (4) also was obtained. Compounds 3 and 4 are the first stable hydroxy- and
siloxygermylene complexes. X-ray analysis of 3 shows an increased coordination of the side-
chain nitrogen atoms to the germanium resulting from the complexation GefW. This
complexation can also explain the significant acidity of the hydroxy group in 3, in the same
range as triphenylgermanol Ph3GeOH.
In tr od u ction
Donor-stabilized germanium(II) compounds have been
developed into an active area of research during the last
two decades. Compounds with side-chain substituents
bearing nitrogen,1 phosphorus,2 and oxygen donors3 are
now known. From this range of compounds, haloger-
mylenes are of particular utility for the synthesis of
many functionalized germylenes using nucleophilic
substitution reactions at germanium. We can expect an
increase in the Lewis base character due to donation of
electron density to the germanium center by the donor
heteroatom and, as a result, a greater ability to form
complexes with Lewis acids such as transition metals.
From a chlorogermylene ArGeCl4 [Ar ) 2,6-bis-
((diethylamino)methyl)phenyl], we report the synthesis
of two new functionalized germylenes ArGeNR2 (R )
F igu r e 1.
W(CO)5, 4. The 2,6-bis((diethylamino)methyl)phenyl
group [Ar] allowed us to obtain the stable chloroger-
mylene ArGeCl and diazogermylene ArGeC(N2)SiMe3,
precursor of a germa-alkyne ArGetCSiMe3.5
i
SiMe3 or Pr) 1. ArGeN(SiMe3)2, 1a , was used to prepare
the first stable hydroxygermylene, stabilized as a pen-
tacarbonyltungsten complex, ArGeOH‚W(CO)5, 3, and
the siloxygermylenetungsten complex ArGeOSiMe3‚
Resu lts a n d Discu ssion
Reaction of ArGeCl4 with lithium bis(trimethylsilyl)-
amide in Et2O in 1:1 ratio at -78 °C afforded ArGeN-
(SiMe3)2, 1a , in 80% yield. The aminogermylene 1b (R
* Corresponding author. Fax: (+33)5-61-55-82-04. E-mail: couret@
chimie.ups-tlse.fr.
(1) (a) Drost, C.; Hitchcock, P. B.; Lappert, M. F.; Pierssens, L. J .-
M. Chem. Commun. 1997, 1141. (b) Leung, W.-P.; Kwok, W.-H.; Weng,
L.-H.; Law, L. T. C.; Zhou, Z. Y.; Mak, T. C. W. J . Chem. Soc., Dalton
Trans. 1997, 4301. (c) Ossig, G.; Meller, A.; Bro¨nneke, C.; Mu¨ller, O.;
Scha¨fer, M.; Herbst-Irmer, R. Organometallics 1997, 16, 2116. (d)
Foley, S. R.; Bensimon, C.; Richeson, D. S. J . Am. Chem. Soc. 1997,
119, 10359. (e) Dias, H. V. R.; Wang, Z. J . Am. Chem. Soc. 1997, 119,
4650. (f) Drost, C.; Hitchcock, P. B.; Lappert, M. F. Organometallics
1998, 17, 3838. (g) Schmidt, H.; Keitemeyer, S.; Neumann, B.;
Stammler, H.-G.; Schoeller, W. W.; J utzi, P. Organometallics 1998,
17, 2149. (h) Benet, S.; Cardin, C. J .; Cardin, D. J .; Constantine, S. P.;
Heath, P.; Rashid, H.; Teixeira, S.; Thorpe, J . H.; Todd, A. K.
Organometallics 1999, 18, 389. (i) J utzi, P.; Keitemeyer, S.; Neumann,
B.; Stammler, H.-G. Organometallics 1999, 18, 4778, and references
therein. (j) Foley, S. R.; Zhou, Y.; Yap, G. P. A.; Richeson, D. S. Inorg.
Chem. 2000, 39, 924.
i
) Pr) was prepared in similar manner. The structure
of 1a is shown in Figure 1. Crystallographic data are
given in Table 1, and selected bond lengths and angles
in Table 2. The Ge(1)-N(1) distance (1.956(0) Å) is the
longest observed σ-Ge(II)-N bond in similar structures;
for example, in [(Me3Si)2N]2Ge, the Ge-N bond dis-
tances are 1.873(5) and 1.878(5) Å,6 and in [Me3SiNC-
(tBu)NSiMe3]GeN(SiMe3)2, it is 1.910(1) Å.1j The Ge(1)-
N(2) dative bond (2.390(3) Å) is as expected much longer
than the covalent Ge(1)-N(1) bond. On the other hand,
the Ge(1)‚‚‚N(3) distance (2.699(1) Å) shows that sig-
nificant coordination between these two atoms is absent.
(2) Karsch, H. H. Russ. Chem. Bull. 1993, 42, 1937, and references
therein.
(3) J utzi, P.; Keitemeyer, S.; Neumann, B.; Stammler, A.; Stammler,
H.-G. Organometallics 2001, 20, 42.
(4) Bibal, C.; Mazie`res, S.; Gornitzka, H.; Couret, C. Submitted for
publication.
(5) Bibal, C.; Mazie`res, S.; Gornitzka, H.; Couret, C. Angew. Chem.,
Int. Ed. 2001, 40 (5), 952.
(6) Chorley, R. W.; Hitchcock, P. B.; Lappert, M. F.; Leung W.-P.;
Power, P. P.; Olmstead, M. M. Inorg. Chim. Acta 1992, 198-200, 203.
10.1021/om020187y CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/04/2002

Germylene-Tungsten Complexes
Organometallics, Vol. 21, No. 14, 2002 2941
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
Deta ils for 1a a n d 3
empirical formula
fw
temp [K]
wavelength [Å]
cryst syst
space group
a [Å]
C22H45GeN3Si2
480.38
193(2)
C21H28GeN2O6W
660.89
193(2)
0.71073
monoclinic
P21/n
10.7885(4)
19.5121(8)
12.2126(5)
107.050(1)
2457.8(2)
4
0.71073
monoclinic
P21/c
16.7379(8)
10.4602(5)
15.9656(8)
103.204(1)
2721.4(2)
4
b [Å]
c [Å]
â [deg]
volume [Å3]
Z
density(calcd)
1.172
1.786
[Mg/m3]
F igu r e 2.
abs coeff [mm-1
]
1.226
5.936
F(000)
1032
1288
Ta ble 3. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for 3
cryst size [mm3]
θ range for data
collection [deg]
range of hkl
0.3 × 0.6 × 0.8
0.4 × 0.1 × 0.05
2.31-29.53
2.03-28.28
Ge(1)-N(2)
Ge(1)-C(1)
Ge(1)-O(1)
Ge(1)-W(1)
2.113(3)
1.975(3)
1.787(2)
2.595(0)
C(1)-Ge(1)-N(2)
O(1)-Ge(1)-C(1)
O(1)-Ge(1)-N(2)
O(1)-Ge(1)-W(1)
N(2)-Ge(1)-W(1)
C(1)-Ge(1)-W(1)
82.70(1)
106.18(1)
101.11(1)
119.78(8)
118.15(7)
121.63(9)
-21 e h e 22
-14 e k e 12
-15 e l e 21
-14 e h e 13
-26 e k e 26
-16 e l e 16
36 524
no. of reflns collected 16 519
no. of ind reflns
abs corr
6928 [Rint ) 0.0371] 6108 [Rint ) 0.0680]
semiempirical
1.000000/0.588755
semiempirical
1.000000/0.493596
6108/0/285
max./min. transmn
metal complex, the pentacarbonyltungsten complex 3
that was obtained by stoichiometric hydrolysis of
1‚W(CO)5 (eq 2):
no. of data/restaints/ 6928/0/263
params
goodness-of-fit on F2 1.029
1.051
R1 ) 0.0266
final R indices
[I>2σ(I)]
R indices (all data)
R1 ) 0.0307
wR2 ) 0.0873
wR2 ) 0.0719
1.826 and -2.188
largest diff peak and 0.0571 and -0.576
hole [e Å-3
]
Ta ble 2. Selected Bon d Len gth s [Å] a n d An gles
[d eg] for 1a
Ge(1)-N(1)
Ge(1)-N(2)
Ge(1)-N(3)
Ge(1)-C(7)
1.956(0)
2.390(3)
2.699(1)
2.022(5)
N(1)-Ge(1)-C(7)
N(2)-Ge(1)-C(7)
N(1)-Ge(1)-N(2)
103.68(6)
78.20(5)
97.90(5)
A major interest of such germylenes 1 is the high
reactivity of the covalent germanium-nitrogen bond
enhanced by the diethylamino NfGe donor interaction.
1 react readily with protic acids A-H and thus are a
suitable starting material for the preparation of het-
eroleptic germylenes ArGe-A. For instance, on reaction
of 1b with 2,4,6-trimethylphenol, the crowded mesityl-
oxygermylene 2 was obtained (eq 1):
Complex 3 was isolated as a colorless powder, which
is soluble in organic solvents. To our knowledge, 3 is
the first stable hydroxygermylene complex, and crystals
suitable for an X-ray structure analysis (Figure 2) were
obtained. Crystallographic data are given in Table 1,
and significant bond lengths and angles are reported
in Table 3. As expected, the coordinate germanium-
nitrogen interaction appears to be enhanced by the
germanium-tungsten interaction: the distance Ge(1)-
N(2) (2.113(3) Å) in 3 is significantly shorter than in
compound 1 (2.390(3) Å). Moreover, the germanium-
oxygen bond length (1.787(2) Å) is the shortest observed
among covalent Ge(II)-O bonds; compare with Ge-O
bond lengths in (tBu3CO)2Ge (1.832(1) and 1.896(6) Å),7
in Ge[OC6H2-4-Me-2,6-tBu2]2 (1.802(8) and 1.812(7) Å),8
in the binuclear germanium calix[4]arene [tBuCalix]Ge2
(1.844(6) Å),9 or in alkoxy-substituted compounds such
as ArGeOiPr (1.856(2) Å) and ArGeOEt (1.844(3) Å)
As expected, 1 are very sensitive toward water, a
reaction that probably gives oligomeric germoxanes
(ArGeO)n. This is in agreement with the well-known
instability of hydroxygermylenes toward self-condensa-
tion and could explain the absence, until now, of stable
compounds of type RGeOH. However, we have suc-
ceeded in stabilizing such a derivative as a transition
(7) Fjelberg, T.; Hitchcock, P. B.; Lappert, M. F.; Smith, S. J .;
Thorne, A. J . J . Chem. Soc., Chem. Commun. 1985, 939.
(8) Cetinkaya, B.; Gu¨mru¨kcu¨, I.; Lappert, M. F.; Atwood, J . L.;
Rogers, R. D.; Zaworotko, M. J . J . Am. Chem. Soc. 1980, 102, 2088.
(9) McBurnett, B. G.; Cowley, A. H. Chem. Commun. 1999, 17.

2942 Organometallics, Vol. 21, No. 14, 2002
Bibal et al.
Ta ble 4. Acid ity of Sever a l Alcoh ols a n d
with, in the latter compounds, Ar ) [2,4-di-tBu-6-
((dimethylamino)methyl)phenyl].1i Among the known
germylene-tungsten complexes, only six have been
characterized by X-ray analysis: RR′GeW(CO)5 com-
plexes (A, R ) C5Me5, R′ ) Cl;10 B, R ) C5Me5, R′ )
(Me3Si)2CH;11 C, R ) R′ ) (2,4,6-tBu3C6H2)Se;12 D, R )
2,4,6-[(Me3Si)2CH]3C6H2, R′ ) 2,4,6-iPr3C6H213) and,
more recently, two germyl(germylene)-tungsten com-
plexes (E, η5-C5Me4EtW(CO)2(dGeMe2)(GeMe3), and F ,
η5-C5Me5W(CO)2(dGeMe2)(GeMe3)).14
Com p a r ison w ith 3
compound
(solution 0.25 M)
ν(OH)a
[cm-1
]
∆ν(Et2O)b
(C6H5)3COH
3611
3678
3650
3645
176
317
196
194
(C6H5)3SiOH
(C6H5)3GeOH
ArGeOH‚W(CO)5
Frequency of the free O-H band in cm-1
.
bFrequency shift
.
a
upon hydrogen bonding to diethyl ether in cm-1
The hydrolysis of the aminogermylene-tungsten com-
plex 1a ‚W(CO)5 gives not only the hydroxygermylene-
tungsten complex 3 but also the siloxygermylene-
tungsten complex 4 in appreciate yield (50%); 4 was
In 3, the germanol acidity is increased by the dative
GefW complexation. Due to both side-chain coordina-
tion and germanium-tungsten bonding, the germanium
atom in hydroxygermylene-tungsten 3 appears to be
almost tetracoordinated. Therefore, it would be interest-
ing to compare its acidity and the resulting reactivity
with germanols, R3GeOH. The acidity of compounds
R3MOH (M ) group 14 element) has been examined
from the change in OH infrared stretching frequency
upon hydrogen bonding to a Lewis base such as diethyl
ether.17 In 3, the frequency of the free OH bond was
found at 3645 cm-1, and the frequency shift upon
hydrogen bonding to diethyl ether was 194 cm-1. These
values show for 3 an acidity in the same range as that
of triphenylgermanol Ph3GeOH (see Table 4). Moreover,
our results confirm that the hydroxy compounds of
germanium are weaker acids than the analogous sil-
anols.
1
characterized by H and 13C NMR and mass spectrom-
etry. While 3 results by direct hydrolytic cleavage of the
Ge-N bond, formation of 4 can be explained by the
hydrolysis of a silicon-nitrogen bond to give the mono-
silylated complex 5 and trimethylsilanol. As it is well
known, silanols R3SiOH exhibit a significant acidity,15
so the formation of 4 could result in the cleavage of the
Ge-N bond of 5 by trimethylsilanol (eq 3):
Con clu sion
Properties of germanium-tungsten complexes often
differ from the behavior of carbene analogues, and we
can reasonably anticipate a specific activity of these
species, especially in organometallic synthesis and in
homogeneous catalysis. This study is in progress.
Exp er im en ta l Section
Air and moisture were excluded from all reactions by use
of standard Schlenk techniques under a nitrogen atmosphere.
Solvents were dried by usual procedures and freshly distilled
before use. 1H NMR spectra were recorded on a Bruker AC
250 spectrometer operating at 250.1 MHz, and 13C NMR
spectra at 62.9 MHz; we use C6D6 as deuterated solvent
(chemical shifts are relative to SiMe4). EI mass spectra were
obtained at 70 eV on a Hewlett-Packard 5989 instrument, and
samples were contained in glass capillaries under argon. IR
spectra were recorded on a Perkin-Elmer 1600 FT-IR spec-
trophotometer. Melting points were taken on a Leitz Biomed
hot-plate microscope apparatus in sealed capillary tubes under
argon and are uncorrected. Elemental analyses were per-
formed by the “Service de Microanalyse de l’Ecole de Chimie
While numerous amino- and thiogermylene-tungsten
complexes have been described,16 alkoxygermylene-
tungsten complexes were unknown until now and the
siloxygermylene complex 4 is the first example of this
class of compounds.
The hydroxygermylene-tungsten complex 3 may be
silylated by a standard silylating reagent (eq 4):
(10) J utzi, P.; Hampel, B.; Stroppel, K.; Kru¨ger, C.; Angermund, K.;
Hofmann, P. Chem. Ber. 1985, 118, 2789.
(11) J utzi, P.; Hampel, B.; Hursthouse, M. B.; Howes, A. J . J .
Organomet. Chem. 1986, 299, 19.
(12) du Mont, W.-W.; Lange, L.; Pohl, S.; Saak, W. Organometallics
1990, 9, 1395.
(13) Tokitoh, N.; Manmaru, K.; Okazaki, R. Organometallics 1994,
13, 167.
(14) Ueno, K.; Yamaguchi, K.; Ogino, H. Organometallics 1999, 18,
4468.
(15) (a) Baney R. H.; Lake K. J .; West R.; Whatley L. S. Chem. Ind.
1959, 1129. (b) West R.; Baney R. H. J . Am. Chem. Soc. 1959, 81, 6145.
(16) For a review, see: Petz, W. Chem. Rev. 1986, 86, 1019.
(17) Matwiyoff, N. A.; Drago, R. S. J . Organomet. Chem. 1965, 3,
393.

Germylene-Tungsten Complexes
Organometallics, Vol. 21, No. 14, 2002 2943
de Toulouse”.The chlorogermylene ArGeCl(Ar )[2,6-bis(diethyl-
amino)methyl]phenyl) was synthesized as described.4
(10 mL) at room temperature. The resulting yellow solution
was stirred for 2 h. Then, a stoichiometric amount of water
(1.27 mmol) was added to the mixture, which was stirred for
a further 1 h. After removal of the solvent under reduced
pressure, the residual yellow oil was subjected to column
chromatography (SiO2, MeOH). Two successive yellow frac-
tions were isolated. The first fraction gave 4 as a waxy material
(0.46 g, 50%). The second fraction gave pure crystals of 3
suitable for X-ray analysis after storage of the pentane solution
at -20 °C for 2 days (0.30 g, 36%).
Ar GeN(SiMe3)2 [Ar ) 2,6-(Et2NCH2)2C6H3] (1a ). A solution
of lithium bis(trimethylsilyl)amide (4.31 mmol) in Et2O (10
mL) prepared by reaction of bis(trimethylsilyl)amine (0.91 mL,
4.31 mmol) with n-BuLi (1.6 M in hexane, 2.96 mL, 4.74 mmol)
was added to a solution of ArGeCl (1.53 g, 4.31 mmol) in THF
(15 mL) at -78 °C. The orange solution was allowed to warm
to room temperature and stirred for 3 h. After removal of
volatile materials, the residue was extracted with pentane (15
mL) and filtered. The filtrate was kept at -20 °C to give yellow
crystals suitable for an X-ray analysis (0.85 g, 41%). Mp: 55
°C. 1H NMR δ [ppm]: 0.08 (s, 9H, SiMe3), 0.58 (s, 9H, SiMe3),
1
Ar GeOH‚W(CO)5 (3). Yield: 36%, 0.30 g. Mp: 110 °C. H
3
NMR δ [ppm]: 0.77 (t, J H/H ) 7.2 Hz, 12H, CH3(Et)), 2.44 (q,
3
3J H/H ) 7.2 Hz, 4H, CH2(Et)), 2.51 (q, J H/H ) 7.2 Hz, 4H,
3
3
2
0.92 (t, J H/H ) 7.2 Hz, 12H, CH3(Et)), 2.59 (q, J H/H ) 7.2 Hz,
CH2(Et)), 3.08, 3.79 (AB system, J H/H ) 13.7 Hz, 4H, CH2),
3
3
4H, CH2(Et)), 2.68 (q, J H/H ) 7.2 Hz, 4H, CH2(Et)), 3.39, 3.96
5.78 (s, 1H, OH), 6.83 (d, J H/H ) 7.9 Hz, 2H, 3,5-aryl-H), 6.96
2
3
3
(AB system, J H/H ) 14.6 Hz, 4H, CH2N), 6.98 (d, J H/H ) 7.4
(t, J H/H ) 7.9 Hz, 1H, 4-aryl-H). 13C NMR δ [ppm]: 9.92
Hz, 2H, 3,5-aryl-H), 7.15 (t, J H/H ) 7.4 Hz, 1H, 4-aryl-H). 13C
(CH3(Et)), 45.55 (CH2(Et)), 58.39 (CH2N), 126.87 (3,5-aryl-C),
129.13 (4-aryl-C), 140.63 (2,6-aryl-C), 153.44 (1-aryl-C), 199.23
(CO), 201.37 (CO). IR (C6D6): 2060, 1970, 1925 cm-1 (νCdO).
3
NMR δ [ppm]: 6.15, 6.87 (SiMe3), 9.56 (CH3(Et)), 45.94 (CH2-
(Et)), 60.92 (CH2N), 123.95 (3,5-aryl-C), 127.40 (4-aryl-C),
145.39 (2,6-aryl-C), 158.99 (1-aryl-C); EI-MS: m/z (%) 481 (M•+
,
EI-MS: m/z (%) 660 (M•+, 1), 642 (M•+ - H2O, 2), 604 (M•+
-
100), 321 (ArGe, 48). Anal. Calcd for C22H45GeN3Si2 (Mr
)
2CO, 2), 520 (M•+ - 5CO, 3), 321 (ArGe, 100). Anal. Calcd for
480.38): C, 55.01; H, 9.44; N, 8.75. Found: C, 54.70; H, 9.65;
N, 8.61.
C21H28N2GeO6W (Mr ) 660.90): C, 38.16; H, 4.27; N, 4.24.
Found: C, 37.93; H, 4.04; N, 4.01.
Ar GeN(iP r )2 (1b). The same procedure as for 1a was used
Ar GeOSiMe3‚W(CO)5 (4). Yield: 50%, 0.46 g. 1H NMR
3
3
for 1b (1.45 g, 80%). 1H NMR δ [ppm]: 0.93 (t, J H/H ) 7.3
δ [ppm]: 0.13 (s, 9H, OSiMe3), 0.85 (t, J H/H ) 7.2 Hz, 12H,
Hz, 12H, CH3(Et)), 1.01 (d, 3J H/H ) 6.7 Hz, 6H, CH3(iPr)), 1.63
CH3(Et)), 2.65 (q, 3J H/H ) 7.2 Hz, 8H, CH2(Et)), 3.68, 3.94 (AB
3
3
2
(d, J H/H ) 6.7 Hz, 6H, CH3(iPr)), 2.65 (q, J H/H ) 7.3 Hz, 4H,
system, J H/H ) 15 Hz, 4H, CH2), 7.16-7.32 (m, 3H, aryl-H).
CH2(Et)), 2.66 (q, 3J H/H ) 7.3 Hz, 4H, CH2(Et)), 3.48 (sept, 3J H/H
13C NMR δ [ppm]: 2.58 (SiMe3), 11.11 (CH3(Et)), 47.53
(CH2(Et)), 58.49 (CH2N), 124.81 (3,5-aryl-C), 130.19 (4-aryl-
C), 143.04 (2,6-aryl-C), 148.75 (1-aryl-C), 199.55 (CO), 200.57
(CO). IR (C6D6): 2061, 1971, 1924 cm-1 (νCdO). EI-MS: m/z
(%) 732 (M•+, 2), 642 (M•+ - HOSiMe3, 17), 321 (ArGe, 66), 73
) 6.7 Hz, 2H, CH(iPr)), 3.53, 3.85 (AB system, J H/H ) 14.0
2
Hz, 4H, CH2N), 7.16-7.21 (m, 3H, aryl-H). 13C NMR δ [ppm]:
9.86 (CH3(Et)), 25.0, 30.90 (CH3(iPr)), 45.23 (CH2(Et)), 53.44
(CH(iPr)), 60.88 (CH2N), 124.70 (3,5-aryl-C), 127.21 (4-aryl-
C), 145.78 (2,6-aryl-C), 158.32 (1-aryl-C). EI-MS: m/z (%): 421
(M•+, 8), 321 (ArGe, 100). Anal. Calcd for C22H41GeN3 (Mr )
420.18): C, 62.89; H, 9.84; N, 10.0. Found: C, 62.35; H, 10.01;
N, 9.83.
(SiMe3, 100). Anal. Calcd for C24H36GeN2O6SiW (Mr
)
733.09): C, 39.32; H, 4.95; N, 3.82. Found: C, 40.47; H, 5.53;
N, 3.47.
Silyla tion of 3. Bis(trimethylsilyl)amine (0.019 g, 0.12
mmol) was added slowly via a microsyringe to a stirring
solution of 3 (0.15 g, 0.23 mmol) in toluene (5 mL) at room
temperature. The mixture was heated at 40 °C for 1 h, and
after evaporation of solvent and ammonia, 4 was obtained (0.15
g, 89%).
Ar GeOMes [Mes ) 2,4,6-Me3C6H2] (2). A solution of
MesOH (0.19 g, 1.39 mmol) in THF (5 mL) was added slowly
to a solution of 1b (0.59 g, 1.39 mmol) in THF (5 mL) at -78
°C. The resulting solution was stirred for 30 min and heated
at reflux for 1 h. The solvents were removed under vacuum to
1
give a waxy product (0.48 g, 75%). H NMR δ [ppm]: 0.80 (t,
X-r a y Str u ctu r e Deter m in a tion for 1a a n d 3. Data of
1a and 3 were collected at low temperature on an oil-coated
shock-cooled crystal on a Bruker-AXS CCD 1000 diffractome-
ter. The structures were solved by direct methods (SHELXS-
97)18 and refined by the least-squares method on F2.19 The R
values are defined as R1 ) ∑|Fo| - |Fc|/∑|Fo| and wR2 )
3J H/H ) 7.3 Hz, 12H, CH3(Et)), 2.25 (s, 3H, p-CH3(Mes)), 2.41
3
(s, 6H, o-CH3(Mes)), 2.565 (q, J H/H ) 7.3 Hz, 4H, CH2(Et)),
3
2.57 (q, J H/H ) 7.3 Hz, 4H, CH2(Et)), 3.48, 3.80 (AB system,
2J H/H ) 14.0 Hz, 4H, CH2N), 6.71-7.16 (m, 5H, aryl-H,
Mes-H). 13C NMR δ [ppm]: 9.31 (CH3(Et)), 19.69 (p-CH3(Mes)),
20.69 (o-CH3(Mes)), 44.84, 44.98 (CH2(Et)), 59.15 (CH2N),
123.68 (2,6-Mes-C), 123.89 (3,5-aryl-C), 128.34 (4-aryl-C),
128.74 (4-Mes-C), 129.46 (3,5-Mes-C), 145.43 (2,6-aryl-C), 152.2
(1-Mes-C), 158.78 (1-aryl-C). EI-MS: m/z (%): 337 (M•+ - Mes,
(∑w(Fo - Fc2)2/∑w(Fo2)2)0.5. Crystal data and structure refine-
2
ment details are listed in Table 1.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, positional and thermal parameters, and selected lengths
and angles. This material is available free of charge via the
Internet at http://pubs.acs.org.
10), 321 (ArGe, 100). Anal. Calcd for C25H38GeN2O (Mr
)
455.18): C, 65.97; H, 8.41; N, 6.15. Found: C, 66.65; H, 8.78;
N, 5.51.
Ar GeOH‚W(CO)5 (3) a n d Ar GeOSiMe3‚W(CO)5 (4). To
a solution of W(CO)5‚THF (1.27 mmol), prepared by the
photolysis of W(CO)6 (0.45 g, 1.27 mmol) in 50 mL of THF
using a low-pressure mercury immersion lamp in a quartz
tube, was added a solution of 1a (0.61 g, 1.27 mmol) in THF
OM020187Y
(18) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, 46, 467.
(19) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen, 1997.