Reaction Modes of a Tetragermabutadiene: Cycloadditions versus Ge-Ge Bond Cleavages

Article abstract of DOI:10.1021/om034123e

Treatment of hexakis(2,4,6-triisopropylphenyl)tetragermabuta-1,3-diene (2) with selenium in the presence of Et₃P furnishes a selenatetragermacyclopentene derivative with an endocyclic Ge-Ge double bond. With small amounts of water 2 reacts to afford an oxatetragermacyclopentane, analogous to THF. The reaction of 2 with Et₃PTe proceeds by cleavage of all Ge-Ge bonds to yield a 1,2,4,5-tetratellura-3,6-digermacyclohexane derivative together with small amounts of the double-decker compound R₄Ge₄Te₆, R = 2,4,6-iPr ₃C₆H₂, and a telluradigermirane. In the reaction of 2 with 2-methoxyphenyl isocyanide one Ge-Ge double bond is cleaved to give the 4(1H)-trigermatimine ring system with an endocyclic Ge-Ge double bond and the known tetrakis(2,4,6-triisopropylphenyl)digermene (10). All new compounds were characterized by X-ray crystallography. Redetermination of the structure of 10 revealed two independent molecules with Ge=Ge bond lengths of 2.2894(6) and 2.2635-(14) A, respectively.

Full text of DOI:10.1021/om034123e

5212
Organometallics 2003, 22, 5212-5216
Rea ction Mod es of a Tetr a ger m a bu ta d ien e:
Cycloa d d ition s ver su s Ge-Ge Bon d Clea va ges1
Gerhard Ramaker, Wolfgang Saak, Detlev Haase, and Manfred Weidenbruch*
Institut fu¨r Reine und Angewandte Chemie, Universita¨t Oldenburg,
Carl-von-Ossietzky-Strasse 9-11, D-26111 Oldenburg, Germany
Received August 22, 2003
Treatment of hexakis(2,4,6-triisopropylphenyl)tetragermabuta-1,3-diene (2) with selenium
in the presence of Et3P furnishes a selenatetragermacyclopentene derivative with an
endocyclic Ge-Ge double bond. With small amounts of water 2 reacts to afford an
oxatetragermacyclopentane, analogous to THF. The reaction of 2 with Et3PTe proceeds by
cleavage of all Ge-Ge bonds to yield a 1,2,4,5-tetratellura-3,6-digermacyclohexane derivative
together with small amounts of the “double-decker” compound R4Ge4Te6, R ) 2,4,6-iPr3C6H2,
and a telluradigermirane. In the reaction of 2 with 2-methoxyphenyl isocyanide one Ge-Ge
double bond is cleaved to give the 4(1H)-trigermatimine ring system with an endocyclic Ge-
Ge double bond and the known tetrakis(2,4,6-triisopropylphenyl)digermene (10). All new
compounds were characterized by X-ray crystallography. Redetermination of the structure
of 10 revealed two independent molecules with GedGe bond lengths of 2.2894(6) and 2.2635-
(14) Å, respectively.
In tr od u ction
a bicyclic compound, which was presumably formed by
[4+2] and [2+2] cycloaddition reactions of oxygen to the
multiple bonds of 2, followed by rearrangement reac-
tions of the two O-O bonds. With sulfur a thiatetrager-
macyclopentene derivative was obtained in high yield.5
We now report on the reactions of 2 with selenium and
tellurium in the presence of Et3P, with water, and with
an aryl isocyanide, which proceed by cycloaddition or
addition reactions or by cleavage of Ge-Ge bonds of 2.
We recently prepared the compounds 12 and 23 as the
first molecules containing conjugated SidSi and Ged
Ge double bonds, respectively. Starting from a tet-
raaryldisilene, compound 1 was obtained by a sequence
of metalation, halogenation, and intermolecular coup-
ling reactions2 and has since been characterized by 1,2-
and 1,4-additions as well as cycloaddition reactions.4
Resu lts a n d Discu ssion
Longer heating of 2 with excess selenium in the
presence of a small amount of triethylphosphane as a
chalcogene transfer reagent furnished yellow crystals
of the selenatetragermacyclopentene 3 that were iso-
lated in 67% yield (eq 1).
Compound 2 is accessible from a tetraaryldigermene
by an analogous sequence of reactions. Although 1 is
formed in yields up to 60%; the synthesis of 2 requires
tedious separation steps and furnishes a maximum yield
of 11%. Very recently we have found that the tet-
ragermabutadiene 2 is easily accessible by the reaction
of an aryl-Grignard compound with GeCl2‚dioxane and
magnesium. Although the yield of this synthetic route
still only amounts to about 30%, the one-pot procedure
does allow the isolation of 2 on a gram scale from readily
accessible or commercially available starting materials
and thus makes investigations of the reactions of 2
possible.5 For example, reaction of 2 with dry air yielded
An X-ray structure analysis of 3 (Figure 1) revealed
the presence of an almost planar five-membered ring
(sum of endocyclic angles: 537.7°). With an average
value of 2.465 Å the Ge(1)-Ge(2) and Ge(3)-Ge(4)
bonds are of a typical size for Ge-Ge single bonds. The
GedGe double bond length of 2.2975(5) Å is somewhat
longer than the corresponding bond in the sulfur-
containing five-membered ring (2.2841 Å).5 Like most
other digermenes, compound 3 shows trans-bending of
the substituents referred to the Ge(2)-Ge(3) vector,
which, in this case, is very pronounced with values of
33.4° at Ge(2) and 35.1° at Ge(3).
*Corresponding author.
(1) Compounds of Germanium, Tin, and Lead. Part 44. Part 43:
Stabenow, F.; Saak, W.; Marsmann, H.; Weidenbruch, M. J . Am. Chem.
Soc. 2003, 125, 10172.
(2) Weidenbruch, M.; Willms, S.; Saak, W.; Henkel, G. Angew. Chem.
1997, 109, 2612; Angew. Chem., Int. Ed. Engl. 1997, 36, 2503.
(3) Scha¨fer, H.; Saak, W.; Weidenbruch, M. Angew. Chem. 2000, 112,
3847; Angew. Chem., Int. Ed. 2000, 39, 3703.
(4) For recent reviews see: (a) Weidenbruch, M. J . Organomet.
Chem. 2002, 646, 39. (b) Weidenbruch, M. Organometallics 2003, 22,
4348.
(5) Ramaker, G.; Scha¨fer, A.; Saak, W.; Weidenbruch, M. Organo-
metallics 2003, 22, 1302.
10.1021/om034123e CCC: $25.00 © 2003 American Chemical Society
Publication on Web 11/06/2003

Reaction Modes of a Tetragermabutadiene
Organometallics, Vol. 22, No. 25, 2003 5213
F igu r e 2. Molecule of 5 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Ge(1)-Ge(2) )
2.5494(4),Ge(2)-Ge(3))2.4551(5),Ge(3)-Ge(4))2.4691(4),
Ge(1)-O ) 1.8183(19), Ge(4)-O ) 1.8319(19), Ge(1)-O-
Ge(4) ) 126.01(9), O-Ge(1)-Ge(2) ) 104.01(12), Ge(1)-
Ge(2)-Ge(3) ) 93.480(14), Ge(2)-Ge(3)-Ge(4) ) 93.895(15),
O-Ge(4)-Ge(3) ) 91.53(6).
F igu r e 1. Molecule of 3 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Ge(1)-Ge(2) )
2.4567(5),Ge(2)-Ge(3))2.2975(5),Ge(3)-Ge(4))2.4755(5),
Ge(1)-Se ) 2.4014(5), Ge(4)-Se ) 2.3921(5), Ge(1)-
Ge(2)-Ge(3))110.064(18),Ge(2)-Ge(3)-Ge(4))109.406(19),
Ge(3)-Ge(4)-Se)102.112(18),Ge(4)-Se-Ge(1))113.758(18),
Se-Ge(1)-Ge(2) ) 102.357(18).
length of 2.55 Å. The same twisting was observed for
the silicon analogue of 5.
The reaction of 2 with selenium closely resembles the
analogous reactions of 1 with sulfur, selenium, and
tellurium6 as well as the reaction of 2 with sulfur.5 The
reactions of 17 and 2 with water also proceed similarly
and lead to saturated five-membered ring compounds
(eq 2).
The reactions of selenium and water with 2 proceed
in analogy with the corresponding reactions of the
tetrasilabutadiene 1. In contrast, the reaction with
tellurium in the presence of triethylphosphane does not
lead to the expected unsaturated five-membered ring
compound but rather proceeds with cleavage of all Ge-
Ge bonds in 2. Isolated from the complex reaction
mixture first, in 15% yield, were light red crystals of a
compound identified by X-ray crystallography (Figure
3) as the 1,2,4,5-tetratellura-3,6-digermacyclohexane 6
(eq 3).
We may assume that the reaction of 2 with water
involves an initial 1,2-addition to one of the Ge-Ge
double bonds with subsequent 1,3-hydride shift and ring
closure. The X-ray crystallographic analysis (Figure 2)
not only confirmed the structure of the oxatetragerma-
cyclopentane 5 but also revealed some interesting
features. The formation of a tetragermanediole followed
by condensation can probably be excluded, since a
similar reaction of a tetrasilanediole was not observed
even under harsh conditions.7
The large twisting of the ring skeleton of 5 is reflected
in the sum of the endocyclic angles of 509° as well as in
the differing Ge-Ge bond lengths. Although the Ge(2)-
Ge(3) and Ge(3)-Ge(4) bonds with an average value of
2.46 Å are in the typical range for Ge-Ge single bonds,
the Ge(1)-Ge(2) bond is markedly stretched with a
The skeletal atoms of the novel ring system 6 com-
prise a highly folded six-membered ring (sum of endocy-
clic angles: 625°) in the twist conformation.
In addition to 6, a few red crystals of another
compound that could only be characterized by X-ray
crystallography (Figure 4) were isolated. This proved
to be the germanium sesquitelluride 7, having a “double-
decker”-type structure with two four-membered rings
and two eight-membered rings. The two four-membered
rings are planar (sum of angles: 359.7°) and are
perpendicular to the common plane of the eight-
(6) Grybat, A.; Boomgaarden, S.; Saak, W.; Marsmann, H.; Weiden-
bruch, M. Angew. Chem. 1999, 111, 2161; Angew. Chem., Int. Ed. 1999,
38, 2010.
(7) Willms, S.; Grybat, A.; Saak, W.; Weidenbruch, M.; Marsmann,
H. Z. Anorg. Allg. Chem. 2000, 626, 1148.

5214 Organometallics, Vol. 22, No. 25, 2003
Ramaker et al.
F igu r e 5. Molecule of 8 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Ge(1)-Te )
2.6107(3), Ge(1)-Ge(1a) ) 2.4694(5), Ge(1)-Te-Ge(1a) )
56.452(12), Ge(1)-Ge(1a)-Te ) 61.774.
F igu r e 3. Molecule of 6 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Ge(1)-Te(1) )
2.5846(5), Te(1)-Te(2) ) 2.7078(4), Te(2)-Ge(2) ) 2.6005(5),
Ge(2)-Te(4) ) 2.5994(5), Te(3)-Te(4) ) 2.7077(4), Te(1)-
Ge(1)-Te(3))106.278(15),Ge(1)-Te(3)-Te(4))102.793(13),
Te(3)-Te(4)-Ge(2) ) 104.458(13), Te(4)-Ge(2)-Te(2) )
105.900(15), Ge(2)-Te(2)-Te(1) ) 102.241(14), Te(2)-
Te(1)-Ge(1) ) 103.553(14).
system is not new. Ando et al. had previously reported
the preparation of an analogous compound by addition
of tellurium to a tetraaryldigermene.9
The differing reactivity of tellurium toward com-
pounds 1 and 2 is probably due to the following factors.
In contrast to the lighter chalcogens, tellurium reacts
much more slowly with the multiple bonds in 1 and 2,
thus making longer reaction times and higher temper-
atures necessary. Although the SidSi bonds in 1 are
stable under these conditions, the GedGe bonds in 2s
in analogy with the behavior of other digermeness
probably dissociate at least in part to afford germylenes
on account of the low bond dissociation energy. Subse-
quent cleavage reactions of the remaining Ge3R4 frag-
ment would then explain the palette of products formed.
The assumption of an initial germylene cleavage is
impressively confirmed by the reaction of 2 with 2-meth-
oxyphenyl isocyanide. The dark red crystals isolated in
59% yield from this reaction were identified as the four-
membered ring compound 9 on the basis of analytical
data and an X-ray crystallographic analysis (Figure 6).
In addition, the digermene 10 resulting from dimeriza-
tion of the germylene was also obtained (eq 4).
F igu r e 4. Molecule of 7 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Te(1)-Ge(1) )
2.5924(9), Te(1)-Ge(2) ) 2.5796(8), Ge(1)-Te(2) ) 2.5899(9),
Ge(1)-Te(3) ) 2.5887(9), Te(2)-Ge(2a) ) 2.5988(10), Te(3)-
Ge(2a) ) 2.5885(9), Ge(1)-Te(1)-Ge(2) ) 106.65(3), Ge(1)-
Te(2)-Ge(2a) ) 85.27(3), Ge(1)-Te(3)-Ge(2a) ) 85.52(3),
Te(2)-Ge(2a)-Te(3) ) 94.34(3), Te(2)-Ge(1)-Te(3) )
94.57(3).
The four-membered ring of 9 is practically planar with
a sum of endocyclic angles of 358.9°. The GedGe bond
length is in the region typical for digermenes. It is not
clear whether the neighboring GedGe and CdN double
bonds are in conjugation to each other. The absorption
maximum in the electronic spectrum occurs in about the
same region as that of, for example, compound 10,11
which seems not to support conjugation. On the other
hand, the dark red color of 9 as well as the absorptions
reaching far into the red region do suggest a bathochro-
mic shift due to conjugation. The situation is apparently
membered rings. A similar structure has been observed
previously only for the sulfur compound (tBuGe)4S6.8
The additionally obtained yellow crystals of the tel-
luradigermirane 8 were also only characterizable by
X-ray crystallography (Figure 5). However, this ring
(8) Ando, W.; Kadowaki, T.; Kabe, Y.; Ishii, M. Angew. Chem. 1992,
104, 84; Angew. Chem., Int. Ed. Engl. 1992, 31, 59.
(9) Tsumuraya, T.; Kabe, Y.; Ando, W. J . Chem. Soc., Chem.
Commun. 1990, 1159.

Reaction Modes of a Tetragermabutadiene
Organometallics, Vol. 22, No. 25, 2003 5215
mp 118-120 °C; 1H NMR δ 0.28 (d, 6 H, 3J ) 6.6 Hz), 0.47 (d,
3
3
3
6 H, J ) 6.6 Hz), 0.69 (d, 6 H, J ) 6.6 Hz), 0.74 (d, 6 H, J
) 6.6 Hz), 0.84 (d, 6 H, 3J ) 6.5 Hz), 0.88 (d, 6 H, 3J ) 6.5
Hz), 1.05 (d, 6 H, 3J ) 6.6 Hz), 1.12 (d, 6 H, 3J ) 6.5 Hz), 1.15
3
3
(d, 6 H, J ) 6.5 Hz), 1.18 (d, 6 H, J ) 6.6 Hz), 1.20 (d, 6 H,
3J ) 6.5 Hz), 1.22 (d, 6 H, J ) 6.5 Hz), 1.24 (d, 6 H, J ) 6.6
3
3
Hz), 1.30 (d, 6 H, 3J ) 6.6 Hz), 1.33 (d, 6 H, 3J ) 6.6 Hz), 1.35
3
3
(d, 6 H, J ) 6.6 Hz), 1.46 (d, 12 H, J ) 6.6 Hz), 2.68 (sept, 2
H), 2.72 (sept, 2 H), 2.82 (sept, 2 H), 3.20 (sept, 2 H), 3.26
(sept, 4 H), 3.58 (sept, 2 H), 3.94 (sept, 2 H), 6.96 (d, 2 H),
6.99 (d, 2 H), 7.03 (d, 2 H), 7.14 (d, 4 H), 7.25 (d, 2 H); 13C
NMR δ 14.20, 22.65, 23.75, 23.92, 24.08, 24.48, 24.64, 25.03,
25.24, 26.21, 26.47, 29.39, 30.16, 34.45, 34.55, 35.36, 36.87,
37.05, 121.72, 122.33, 122.58, 124.44, 141.12, 151.72, 154.01,
157.2; UV/vis (n-hexane) λmax(ꢀ) 399 nm (430). Anal. Calcd for
C
90H138Ge4Se: C, 68.01; H, 8.75; Se, 4.97. Found: C, 67.65;
H, 8.95; Se, 4.80. Single crystals of 3 were grown from toluene
at -4 °C.
2,2,3,4,5,5-H exa k is(t r iisop r op ylp h en yl)-1-oxa -2,3,4,5-
tetr a ger m a cyclop en ta n e (5). To a solution of 2 (0.40 g, 0.26
mmol) in n-hexane (30 mL) was added an excess of water (0.10
g, 5.5 mmol) and the mixture heated under reflux for 12 h.
During this time the color changed from blue-black to pale
orange. n-Hexane was replaced by n-pentane, and all insoluble
products were filtered off. Crystallization from n-hexane at -4
°C furnished pale yellow crystals of 5 (0.33 g, 82%), mp 103-
F igu r e 6. Molecule of 9 in the crystal (hydrogen atoms
omitted). Ellipsoids are drawn at 50% probability. Selected
bond lengths (Å) and bond angles (deg): Ge(1)-Ge(2) )
2.4297(8), Ge(2)-Ge(3) ) 2.2808(7), Ge(1)-C(1) ) 2.028(5),
Ge(3)-C(1) ) 1.999(5), C(1)-N ) 1.269(6), Ge(1)-Ge(2)-
Ge(3) ) 83.70(2), Ge(2)-Ge(3)-C(1) ) 88.40(14), Ge(3)-
C(1)-Ge(1) ) 102.7(2), C(1)-Ge(1)-Ge(2) ) 83.75(15).
1
3
3
105 °C; H NMR δ 0.47 (d, 6 H, J ) 6.6 Hz), 0.56 (d, 6 H, J
) 6.6 Hz), 0.61 (d, 6 H, 3J ) 6.6 Hz), 0.70 (d, 6 H, 3J ) 6.6
Hz), 0.74 (d, 6 H, 3J ) 6.6 Hz), 0.77 (d, 6 H, 3J ) 6.6 Hz), 0.99
less ambiguous in a five-membered ring system with
neighboring SidGe and CdC double bonds in which no
conjugation is observed between these bonds.12
3
3
(d, 6 H, J ) 6.6 Hz), 1.09 (d, 6 H, J ) 6.6 Hz), 1.16 (d, 6 H,
3J ) 6.6 Hz), 1.18 (d, 6 H, J ) 6.6 Hz), 1.20 (d, 6 H, J ) 6.6
3
3
Hz), 1.25 (d, 6 H, 3J ) 6.6 Hz), 1.29 (d, 6 H, 3J ) 6.6 Hz), 1.33
The digermene 10 also obtained in this reaction has
been known for some time10,11,13 and has also been
structurally characterized. As a consequence of a non-
resolvable disorder of the germanium atoms, a too short
length of 2.213(1) Å was reported for the Ge-Ge double
bond.10 As a consequence of a better crystal quality, it
has now been possible to resolve this disorder and de-
monstrate the presence of two independent molecules
with bond lengths of 2.2894(6) and 2.2635(15) Å, typical
of digermenes with this substitution pattern. A figure
is not provided here because the forms of the two
molecules do not differ from that already reported.10
3
3
(d, 6 H, J ) 6.6 Hz), 1.36 (d, 6 H, J ) 6.6 Hz), 1.38 (d, 6 H,
3J ) 6.6 Hz), 1.41 (d, 6 H, J ) 6.6 Hz), 1.45 (d, 6 H, J ) 6.6
Hz), 2.67 (sept, 2 H), 2.72 (sept, 2 H), 2.82 (sept, 2 H), 3.20
(sept, 2 H), 3.26 (sept, 2 H), 3.60 (sept, 2 H), 3.70 (sept, 2 H),
4.02 (sept, 2 H), 4.20 (sept, 2 H), 5.61 (s, 2 H), 6.96 (d, 4 H),
6.99 (d, 2 H), 7.03 (d, 2 H), 7.18 (d, 2 H), 7.26 (d, 2 H); owing
to the strongly twisted structure of 5, all 1H-resonances appear
separately; 13C NMR δ 23.75, 23.93, 23.98, 24.09, 24.21, 24.26,
24.48, 24.64, 25.03, 25.25, 26.22, 26.47, 29.39, 34.45, 35.36,
36.87, 37.05, 118.90, 121.60, 121.72, 122.30, 122.58, 122.77,
123.29, 123.76, 123.94, 124.44, 136.89, 139.84, 150.56, 150.97,
151.12, 151.72, 152.23, 154.01, 157.28, 159.69. Anal. Calcd for
3
3
C
90H140Ge4O: C, 70.72; H, 9.23. Found: C, 70.45; H, 9.04.
Single crystals of 5 were grown from toluene at -4 °C.
3,3,6,6-Tetr a k is(2,4,6-tr iisop r op ylp h en yl)-1,2,4,5-tetr a -
t ellu r a -3,6-d iger m a cycloh exa n e (6). Triethylphosphane
telluride (0.30 g, 1.22 mmol, excess) was added to a solution
of 2 (0.82 g, 0.54 mmol) in toluene (30 mL) and the mixture
heated for 12 h at 80 °C. Toluene was replaced by n-pentane,
and all insoluble compounds were filtered off. The solvent was
evaporated and the residue redissolved in toluene to afford a
small amount of dark red crystals of 7. Crystallization from
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were carried out
in oven-dried glassware under an atmosphere of dry argon.
The H and 13C NMR spectra were obtained on a Bruker ARX
1
500 spectrometer using C6D6 as solvent. The UV/vis spectra
were recorded with a Comspec spectrometer with fiber optics.
Elemental analyses were performed by Analytische Labora-
torien, D-51779 Lindlar, Germany.
methylcyclopentane furnished
a small amount of yellow
2,2,3,4,5,5-Hexa k is(2,4,6-tr iisop r op ylp h en yl)-1-selen a -
2,3,4,5-tetr a ger m a cyclop en t-3-en e (3). Selenium (0.10 g,
12.7 mmol) and a few drops of Et3P were added to a solution
of 2 (0.62 g, 0.41 mmol) in n-hexane (30 mL), and the mixture
was heated under reflux for 5 h. During this time the color
changed from blue-black to yellow. n-Hexane was replaced by
n-pentane (30 mL), excess selenium was filtered off, and the
solvent was evaporated. Crystallization from a minimum
amount of toluene provided yellow crystals of 3 (0.44 g, 67%):
crystals of 8. Repeated crystallization from n-hexane yielded
pale red crystals of 6 (0.12 g, 15% yield), mp > 210 °C (dec);
1H NMR δ 0.88 (d, 12 H, J ) 6.6 Hz), 0.95 (d, 6 H, J ) 6.7
Hz), 1.00 (d, 6 H, 3J ) 6.6 Hz), 1.12 (d, 24 H, 3J ) 6.6 Hz),
1.17-1.46 (m, 24 H), 2.67 (sept, 4 H), 3.37 (sept, 4 H), 4.53
(sept, 4 H), 6.99 (s, 4 H), 7.08 (s, 4 H); 13C NMR δ 22.33, 22.59,
22.99, 23.57, 23.94, 24.57, 27.09, 31.90, 34.51, 35.48, 37.82,
122.71, 124.65, 129.34, 136.77, 143.07, 150.80, 151.51, 153.22.
Anal. Calcd for C60H92Ge2Te4: C, 49.06; H, 6.31. Found: C,
50,69; H, 6.70. Single crystals of 6 were grown from n-hexane
at -4 °C.
3
3
(10) Scha¨fer, H.; Saak, W.; Weidenbruch, M. Organometallics 1999,
18, 3159.
(11) Park, J .; Batcheller, S. A., Masamune, S. J . Organomet. Chem.
1989, 367, 39.
(12) Lee, V. Y.; Ichinohe, M.; Sekiguchi, A. J . Am. Chem. Soc. 2000,
122, 12604.
(13) Ando, W.; Itoh, H.; Tsumuraya, T. Organometallics 1989, 8,
2759.
2-Meth oxy-N-[1,1,2,3-tetr akis(2,4,6-tr iisopr opylph en yl)-
4(1H)-tr iger m eth ylid en e]a n ilin e (9). To a solution of 2
(0.44 g, 0.29 mmol) in n-hexane (30 mL) was added 0.5 mL of
2-methoxyphenyl isocyanide (0.54 g, 4.1 mmol), and the
mixture was heated for 3 h at 60 °C. During this time the color

5216 Organometallics, Vol. 22, No. 25, 2003
Ta ble 1. Cr ysta llogr a p h ic Da ta for 3, 5, 6, a n d 7
Ramaker et al.
3
5
6
7
formula
fw
a (Å)
b (Å)
c (Å)
C
90H138Ge4Se‚1.5 C7H8
C
90H140Ge4O‚1/2C7H8
C
60H92Te4‚1/2C6H14
C
60H92Ge4Te6‚4C7H8
1589.46
14.9502(7)
17.0382(11)
20.5480(9)
69.423(6)
79.093(5)
85.579(7)
4811.3(4)
2
1528.51
15.0722(4)
15.0795(5)
23.4233(10)
98.857(5)
99.257(4)
117.922(3)
4479.3(3)
2
1468.99
10.5768(3)
15.9415(7)
21.3704(9)
80.087(5)
82.569(5)
85.286(3)
3513.0(2)
2
1869.41
17.5800(6)
28.5040(14)
18.3953(8)
90
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
90
90
9217.9(7)
4
1.613
Dcalcd (g cm-3
)
1.192
1.166
2.516
cryst size (mm)
cryst syst
space group
0.80 × 0.30 × 0.14
triclinic
P1h
0.47 × 0.24 × 0.16
triclinic
P1h
0.50 × 0.19 × 0.02
triclinic
P1h
0.20 ×0.13 × 0.04
orthorhombic
Pbca
52
64 739
8852
0.0407
0.0762
0.741
2θmax (deg)
52
52
52
no. of reflns measd
no. of unique reflns
R (I > 2σ(I))
wR2 (all data)
GOF (F2)
58 725
17 308
0.0415
0.1068
41 366
16 428
0.0395
0.1012
43 491
12 802
0.0298
0.0693
0.930
0.971
0.909
Ta ble 2. Cr ysta llogr a p h ic Da ta for 8, 9, a n d 10
changed from blue-black to red. n-Hexane was replaced by
n-pentane, and all insoluble products were filtered off. n-
Pentane was evaporated and the residue redissolved in n-
hexane to furnish dark red crystals of 9 (0.20 g, 59%), mp 87-
8
9
10
formula
C
60H92Ge2Te
C68H99Ge3NO‚
2C6H12
C
60H92Ge2
3
3
89 °C; 1H NMR δ 0.69 (d, 6 H, J ) 6.6 Hz), 0.74 (d, 6 H, J )
fw
1090.15
22.4018(5)
9.7280(3)
26.7946(5)
90
96.545(3)
90
5801.1(3)
4
1164.35
11.8412(2)
32.2192(11)
21.0546(6)
90
101.127(3)
90
7881.6(4)
4
958.52
3
3
6.6 Hz), 1.06 (d, 6 H, J ) 6.6 Hz), 1.13 (d, 6 H, J ) 6.6 Hz),
a (Å)
b (Å)
c (Å)
13.1667(6)
13.5646(7)
18.2962(7)
98.402(5)
96.913(5)
112.121(5)
2939.2(2)
2
3
3
1.17 (d, 6 H, J ) 6.6 Hz), 1.19 (d, 6 H, J ) 6.6 Hz), 1.21 (d,
3
3
3
6 H, J ) 6.6 Hz), 1.26 (d, 6 H, J ) 6.6 Hz), 1.29 (d, 6 H, J
) 6.6 Hz), 1.33 (d, 6 H, 3J ) 6.6 Hz), 1.35 (d, 6 H, 3J ) 6.6
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
3
Hz), 1.46 (d, 6 H, J ) 6.6 Hz), 2.67-2.82 (m, 12 H), 3.31 (s, 3
H), 6.30-6.45 (m, 4 H), 6.88 (d, 2 H), 6.98 (d, 2 H), 7.11-7.15
(m, 4 H); 13C NMR δ 24.07, 24.18, 24.38, 24.86, 34.62, 34.72,
35.99, 38.87, 55.71, 112.34, 118.52, 120.35, 121.18, 121.86,
122.16, 122.37, 125.20, 140.45, 144.37, 146.27, 149.52, 150.49,
151.14, 151.98, 153.20, 153.78; UV/vis (n-hexane) λmax(ꢀ) 406
Dcalcd (g cm-3
)
1.248
1.123
1.083
cryst size (mm) 0.33 × 0.23 × 0.70 × 0.05 × 0.30 × 0.23 ×
0.15
monoclinic
C2/c
52
22 519
0.05
monoclinc
P21/n
52
65 598
0.10
triclinic
P1h
nm (43400, tailing off in the red region). Anal. Calcd for C68H99
-
cryst syst
Ge3NO: C, 70.14; H, 8.57. Found: C, 69.81; H, 8.70. Single
crystals of 9 were grown from methylcyclopentane at -4 °C.
Crystallization from diethyl ether furnished the already known
tetrakis(2,4,6-triisopropylphenyl)digermene (10).
space group
2θmax (deg)
no. of reflns
measd
52
36 591
no. of unique
reflns
5403
14 553
10 752
Cr ysta llogr a p h ic An a lyses. Crystal and numerical data
of the structure determinations are given in Table 1 and Table
2. In each case the crystal was mounted in an inert oil. Data
collection was performed with a Stoe IPDS area detector at
193(2) K using graphite-monochromated Mo KR radiation. The
structures were solved by direct phase determination and
refined by full-matrix least-squares techniques against F2 with
the SHELXL-97 program system.14 Hydrogen atoms were
placed in the calculated positions, and all other atoms were
refined anisotropically. The data have been deposited with the
Cambridge Crystallographic Data Centre: CCDC-216 885 (3),
CCDC-216 888(5), CCDC-216 883 (6), CCDC-216 890 (7),
CCDC-216 887 (8), CCDC-216 886 (9), and CCDC-216 889 (10).
R (I > 2σ(I))
wR2 (all data)
GOF (F2)
0.0336
0.0895
1.015
0.0557
0.1272
0.848
0.0346
0.0706
0.847
Ack n ow led gm en t. Financial support of our work
by the Deutsche Forschungsgemeinschaft and the Fonds
der Chemischen Industrie is gratefully acknowledged.
Su p p or t in g In for m a t ion Ava ila b le: Listing of atomic
coordinates, anisotropic displacement parameters, and bond
lengths and angles for 3, 5, 6, 7, 8, 9, and 10. This material is
available free of charge via the Internet at http://pubs.acs.org.
(14) Sheldrick, G. M. SHELXL-97, Program for crystal structure
refinement; Universita¨t Go¨ttingen: Go¨ttingen, Germany, 1997.
OM034123E