Reactivity of germene mes2Ge=CR2 with cumulative unsaturation-containing compounds: Synthesis of new germanium heterocycles

Article abstract of DOI:10.1021/om0504607

Germene 1 reacts with the CO and CS double bonds respectively of phenylisocyanate and methylisothiocyanate by formal [2+2] cycloadditions, leading to four-membered ring derivatives 2 and 3. With CS₂, dithiagermolane 11 and dithiadigermetane 12

Full text of DOI:10.1021/om0504607

5364
Organometallics 2005, 24, 5364-5368
Reactivity of Germene Mes2GedCR2 with Cumulative
Unsaturation-Containing Compounds: Synthesis of New
Germanium Heterocycles
Sakina Ech-Cherif El Kettani,† Mohamed Lazraq,† Henri Ranaivonjatovo,‡
Jean Escudie´,*,‡ Claude Couret,‡ Heinz Gornitzka,‡ and Aziz Atmani†
Laboratoire de Chimie Organique, BP 1796, Faculte´ des Sciences Dhar El Mehraz,
Universite´ Sidi Mohamed Ben Abdellah, Fe`s-Atlas, Fe`s, Morocco, and He´te´rochimie
Fondamentale et Applique´e, UMR 5069, Universite´ Paul Sabatier, 118 Route de Narbonne,
31062 Toulouse Cedex 9, France
Received June 7, 2005
Germene 1 reacts with the CO and CS double bonds respectively of phenylisocyanate and
methylisothiocyanate by formal [2+2] cycloadditions, leading to four-membered ring
derivatives 2 and 3. With CS2, dithiagermolane 11 and dithiadigermetane 12 are obtained;
the first step of this reaction is probably a formal [2+2] cycloaddition between the GedC
and CdS double bonds. With nitromethane, oxazadigermolidine 19 and fluorenone are
obtained, the first step likely being a [2+3] cycloaddition between the GedC double bond
and the NO2 moiety. Compounds 11 and 19 were characterized by X-ray diffraction analysis.
Introduction
two adjacent double bonds, their behavior toward met-
allaalkenes is poorly documented.
Metallaalkenes >MdC< (M ) Si, Ge, Sn)1 are im-
portant building blocks in organometallic chemistry
owing to the great reactivity of the MdC double bond
toward electrophiles and nucleophiles and in various
types of cycloaddition with many unsaturated species.
Among all the “heavy” alkenes synthesized so far,
dimesitylfluorenylidene germane Mes2GedCR2 (Mes )
2,4,6-trimethylphenyl, CR2 ) fluorenylidene) 12 pre-
sents additional interest due to the conjugation between
the GedC double bond and the fluorenylidene moiety:
a rather unusual cycloaddition takes place between 1
and tert-butylphosphaacetylene3a or phenylacetonitrile.3b
These reactions may begin with a formal [2+2] cyclo-
addition between the germene and the alkynes, with the
germene acting as the 4π-component.
We present in this paper new investigations in this
field by the study of the reactions of germene 1 with
phenylisocyanate, methylisothiocyanate, carbon disul-
fide, and nitromethane.
Results and Discussion
(a) Reaction of 1 with PhNCO and MeNCS.
Addition of phenylisocyanate and methylisothiocyanate,
at room temperature, to crude solutions of germene 1,2
prepared by dehydrofluorination of Mes2Ge(F)CHR2 by
t-BuLi in Et2O, afforded the four-membered heterocycles
oxagermetane 2 and thiagermetane 3 in nearly quan-
titative yields (Scheme 1). These reactions are regio- and
chemoselective, involving formal [2+2] cycloadditions
between the GedC unsaturation and the CdO and CdS
double bonds, respectively; no reaction of the CdN
unsaturation was observed: oxygen and sulfur are
bonded to germanium as expected from the polarity of
the CdO and CdS moieties and that of the GedC
double bond (Geδ+dCδ-). The formation of strong
Ge-O and Ge-S bonds is another driving force for the
Although compounds containing cumulative unsat-
urations offer several possibilities for reaction with
“heavy” low-coordinate species owing to the presence of
† Universite´ Sidi Mohamed Ben Abdellah.
‡ Universite´ Paul Sabatier.
(1) For reviews, see: (a) Escudie´, J.; Couret, C.; Ranaivonjatovo, H.;
Satge´, J. Coord. Chem. Rev. 1994, 130, 427. (b) Escudie´, J.; Couret,
C.; Ranaivonjatovo, H. Coord. Chem. Rev. 1998, 178-180, 565. (c)
Escudie´, J.; Ranaivonjatovo, H. Adv. Organomet. Chem. 1999, 44, 113.
(d) Lee, V. Ya.; Sekiguchi, A. Organometallics 2004, 23, 2822. (e)
Baines, K. M.; Stibbs, W. G. Adv. Organomet. Chem. 1996, 39, 275. (f)
Brook, A. G.; Brook, M. A. Adv. Organomet. Chem. 1996, 39, 71. (g)
Mu¨ller, T.; Ziche, W.; Auner, N. In The Chemistry of Organic Silicon
Compounds; Rappoport, Z., Apeloig, Y., Eds.; Wiley: New York, 1998;
Vol. 2, Chapter 16. (h) Brook, A. G. In The Chemistry of Organic Silicon
Compounds; Rappoport, Z., Apeloig, Y., Eds.; Wiley: New York, 1998;
Chapter 21.
Scheme 1
(2) (a) Couret, C.; Escudie´, J.; Satge´, J.; Lazraq, M. J. Am. Chem.
Soc. 1987, 109, 4411. (b) Lazraq, M.; Escudie´, J.; Couret, C.; Satge´, J.;
Dra¨ger, M.; Dammel, R. Angew. Chem., Int. Ed. Engl. 1988, 27, 828.
(3) (a) Lazraq, M.; Escudie´, J.; Couret, C.; Bergstra¨sser, U.; Regitz,
M. Chem. Commun. 1993, 569. (b) Ech-Cherif El Kettani, S.; Lazraq,
M.; Ranaivonjatovo, H.; Escudie´, J.; Couret, C.; Gornitzka, H.; Mer-
ceron, N. Organometallics 2004, 23, 5062.
10.1021/om0504607 CCC: $30.25 © 2005 American Chemical Society
Publication on Web 09/17/2005

Synthesis of New Germanium Heterocycles
Organometallics, Vol. 24, No. 22, 2005 5365
cycle, the 1-aza-2-germacyclobutene 9,3b leading to tetra-
mesityldioxadigermetane 4 and fluorenyl(tert-butyl)-
ketone 10 (eq 1).
Chart 1
Scheme 2
Similar reactions involving exclusively the CdS double
bond of phenylisothiocyanate have been observed with
metallathiones and metallaselenones >MdX (M ) Si,
8
X ) S;6 M ) Ge, X ) S,7 Se ). Between germanimines
>GedN- and MeNdCdS or PhNdCdS, the reactions
are not chemoselective: additions onto both the CdN
and CdS bonds have been observed.9 By contrast to 1,
germanimines >GedN- react with the CdN double
bond of PhNCO9 to give the corresponding four-
membered heterocycle. An unexpected reaction occurs
between disilene t-Bu2SidSit-Bu2 and t-Bu3SiNdCdO,
the first step being a [3+2] cycloaddition between the
SidSi double bond and the NCO moiety.10
Thus, our results show a close similarity in chemical
behavior between the GedC double bond of germene 1
and the GedS, GedSe, and SidS double bonds of
germathiones, germaselenones, and silathiones toward
isocyanates and isothiocyanates. The more polar GedN
double bond of germanimines shows different chemo-
selectivity.
(b) Reaction of 1 with CS2. When 1 equiv of carbon
disulfide was added to a solution of germene 1 cooled
to -78 °C, a violet color appeared immediately. After 7
h of stirring at room temperature and usual workup, a
fractional crystallization successively afforded the five-
membered heterocycle 2-fluorenylidene-1,3,4-dithia-
germolane 11 and 2,2,4,4-tetramesityl-1,3,2,4-dithiadi-
germetane 12. Other experimental conditions (addition
of germene 1 to CS2 or the reaction performed at room
temperature) led to the same result (eq 2).
formation of such regioisomers. Thus, the first step in
these reactions could be the nucleophilic attack of the
heteroatom (O or S) onto the germanium followed by
cyclization.
The CdN moiety of 2 and 3 was evidenced by IR (νCd
N: 1690 cm-1) and 13C NMR (δCdN 171.55 ppm for 2
and 160.71 ppm for 3) spectroscopies. Their structures
were also elucidated from their mass spectra, which
display, besides the molecular peak, the fragments
corresponding to the two possible [4] f [2+2] decom-
positions; path (b) is favored, particularly when E ) S
(Chart 1).
The structures of 2 and 3 were chemically confirmed
by their hydrolysis, leading quantitatively to tetra-
mesityldioxadigermetane 4,4 to amide 5 (from 2), and
to thioamide 6 (from 3) (Scheme 2). 4 was formed from
dihydroxygermane 7, which slowly loses H2O in solution
at room temperature as previously reported.5 Com-
pounds 5 and 6 could not be isolated in completely pure
form, but their structures were assigned by 1H and 13
C
NMR (5 δCdO: 168.77 ppm, 6 δCdS: 201.96 ppm) and
mass spectrometry.
Formation of 1211 obviously arises from the dimer-
ization of the transient dimesitylgermanethione 13, but
that of 11 deserves some comment (Scheme 3). Unfor-
tunately, as no intermediate could be isolated or char-
acterized, only hypotheses can be formulated. By com-
parison with the reaction of 1 with MeNdCdS, the first
step of the reaction is possibly the formation of the four-
membered ring derivative 14 by a [2+2] cycloaddition
between the GedC and one of the CdS double bonds.
This heterocycle could then undergo a [4] f [2+2]
fragmentation, a well-known process in four-membered
The formation of 4, 5, and 6 can occur by route (a)
(initial cleavage of the Ge-C bond) or route (b) (initial
cleavage of the Ge-O or Ge-S bond). Standard Ge-C
bonds are generally more resistant to hydrolysis than
Ge-O or Ge-S bonds; however, they should be weak-
ened in 2 and 3 due to the strain in the four-membered
ring and their expected elongation caused by the steric
repulsion between the Mes and CR2 groups.
In the absence of isolation or characterization of the
intermediates it is not possible to determine which of
the hydrolysis routes (a) or (b) is occurring since both
lead to 7 and 8 then to 4, 5, and 6.
(6) Suzuki, H.; Tokitoh, N.; Nagase, S.; Okazaki, R. J. Am. Chem.
Soc. 1994, 116, 11578.
A cleavage of the Ge-C bond has recently been
observed in the hydrolysis of a four-membered hetero-
(7) Tokitoh, N.; Matsumoto, T.; Manmaru, K.; Okazaki, R. J. Am.
Chem. Soc. 1993, 115, 8855.
(8) Matsumoto, T.; Tokitoh, N.; Okazaki, R. Angew. Chem., Int. Ed.
Engl. 1994, 33, 2316.
(4) (a) Duverneuil, G.; Mazerolles, P.; Perrier, E. Appl. Organomet.
Chem. 1994, 8, 119. (b) Samuel, M. S.; Jennings, M. C.; Baines, K. M.
J. Organomet. Chem. 2001, 636, 130.
(5) (a) El Baz, F.; Rivie`re-Baudet, M.; Chazalette, C.; Gornitzka, H.
Phosphorus, Sulfur Silicon 2000, 163, 121. (b) Rivie`re-Baudet, M.; El
Baz, F.; Satge´, J.; Khallaayoun, A.; Ahra, M., Phosphorus, Sulfur
Silicon 1996, 112, 203.
(9) Lacrampe, G.; Lavayssiere, H.; Rivie`re-Baudet, M.; Satge´, J. Recl.
Trav. Chim. Pays-Bas 1983, 102, 21.
(10) Weidenbruch, M.; Flintjer, B.; Pohl, S.; Saak, W. Angew. Chem.,
Int. Ed. Engl. 1989, 28, 95.
(11) Tsumuraya, T.; Sato, S.; Ando, W. Organometallics 1988, 7,
2015.

5366 Organometallics, Vol. 24, No. 22, 2005
Ech-Cherif El Kettani et al.
Chart 2
Scheme 3
Chart 3
organometallic heterocycles. An argument for this as-
sumption is the observation in mass spectrometry of a
facile decomposition in the similar four-membered ring
compound 3 obtained from MeNdCdS and 1. The very
reactive thioketene 1512 should then react with 14 by a
regioselective insertion of the CS moiety into the Ge-S
bond, leading to intermediate 16, which finally loses CS
to form the dithiagermolane 11. Such a loss of CdS in
organometallic heterocycles has previously been ob-
served.13 The fact that the dithiadigermetane 12 is
obtained in a much better yield (83%) than 11 (17%),
whose formation needs an additional step, is also an
argument for this mechanism.
C(R2) bond, which is slightly elongated (2.014(4) Å)
compared to the standard values (1.93-1.98 Å15) (Figure
1).
(c) Reaction of 1 with MeNO2. Germene 1 reacts
with nitromethane to give the air- and moisture-stable
1,3,2,5-oxazadigermolidine 19 and fluorenone 20 (Scheme
4). Irrespective of the reaction conditions, this reaction
consumes 2 equiv of germene and 1 equiv of MeNO2.
The most likely mechanism involves the initial [2+3]
cycloaddition between the GedC double bond and ni-
tromethane with formation of the heterocycle 21, which
undergoes a [5] f [3+2] decomposition leading to
fluorenone and the oxazagermirane 22 followed by ring
expansion of the latter by reaction with 1 (Scheme 4).
Similar “two-atom insertion” of olefins into three-
membered rings is a well-known process.
Formation of 11 from spiro compound 17 (Scheme 3)
by a rearrangement involving the loss of germylene
Mes2Ge can be ruled out since with 2 equiv of germene
1, 17 is not formed: in this case 1 equiv of unreacted
germene is recovered along with 11 and 12.
Such [2+3] cycloadditions between the NO2 moiety
of nitrobenzene and the SidSi double bond of disilenes16
or the CdC double bond of an alkene17 have been
previously reported.
Such a [2+2] cycloaddition between the GeN double
bond of germanimines and CS2 leading to transient four-
membered ring heterocycles 18 followed by their [4] f
The structure of 19 was evidenced by its NMR data.
9,14
1
[2+2] decomposition has been previously reported
(eq 3).
In H NMR spectroscopy, four signals are observed as
Compound 11 has been characterized by mass spec-
1
trometry and H NMR spectroscopy: the protons 1-8
of the CR2 group bonded to the germanium atom
(perpendicular to the five-membered ring plane) give
rise to four signals (proton 1 equivalent to 8, 2 to 7, 3 to
6, and 4 to 5) (see numbering in Chart 3), giving two
doublets and two triplets. By contrast, four doublets and
four triplets are observed as expected for the proton of
the other CR2 group, since H1-8 are nonequivalent. The
o-Me groups of mesityl groups display a very broad
singlet due to their slow rotation.
Figure 1. Molecular structure of 11 with ellipsoids drawn
at the 50% probability level. Selected bond lengths (Å) and
angles (deg). H atoms are omitted for clarity. Ge-C1 )
2.014(4), Ge-C28 ) 1.986(4), Ge-C37 ) 1.983(4), Ge-S2
) 2.2549(11), S2-C2 ) 1.773(4), S1-C2 ) 1.762(4), S1-
C1 ) 1.832(4), C2-C3 ) 1.348(5), S2-Ge-C1 ) 93.05(11),
Ge-C1-S1 ) 102.75(18), C1-S1-C2 ) 101.68(18), C2-
S2-Ge ) 100.15(13), S2-C2-S1 ) 115.6(2), S2-C2-C3
) 122.2(3), S1-C2-C3 ) 122.2(3).
11, unlike 2 and 3, is stable toward air and moisture.
Its structure was established by an X-ray analysis,
which shows standard bond lengths except for the Ge-
(12) Seybold, G.; Heibl, C. Chem. Ber. 1977, 110, 1225.
(13) Procopio, L. J.; Caroll, P. J.; Berry, D. H. Organometallics 1993,
12, 3087.
(14) Veith, M.; Detemple, A. Phosphorus, Sulfur Silicon 1992, 65,
17.

Synthesis of New Germanium Heterocycles
Organometallics, Vol. 24, No. 22, 2005 5367
Scheme 4
expected for the o- and p-Me of the mesityl groups,
showing that the two mesityl groups on each Ge atom
are equivalent due to a rapid inversion of nitrogen on
the NMR time scale. The very broad signal at 1.71 ppm
can be attributed to the o-Me groups of the Mes2Ge
bonded to the CR2 group, the rotation of these mesityl
groups probably being hindered for steric reasons. In
mass spectrometry, besides the molecular peak, the
main fragment was Mes2GeOGeMes2 resulting from a
[5] f [3+2] fragmentation (Chart 2).
An X-ray-structure determination study unambigu-
ously established the structure of 19 (Figure 2). A long
Ge1-C(R2) bond (2.060(11) Å) was observed due to the
large steric hindrance caused by the Mes and CR2
groups. A rather surprising feature is the great differ-
ence in the Ge-C(Mes) bond lengths for the same
GeMes2 moiety: 2.001(9) and 1.960(11) Å for Ge(1)Mes2,
2.016(10) and 1.933(11) Å for Ge(2)Mes2.
Figure 2. Molecular structure of 19 with ellipsoids drawn
at the 50% probability level. Selected bond lengths (Å) and
angles (deg). H atoms are omitted for clarity. Ge1-O )
1.806(6), Ge2-O ) 1.756(6), Ge2-N ) 1.841(9), Ge1-C2
) 2.060(11), N-C2 ) 1.472(14), N-C1 ) 1.481(13), Ge1-
C24 ) 2.016(10), Ge1-C15 ) 1.933(11), Ge2-C33 )
1.960(11), Ge2-C42 ) 2.001(9), O-Ge2-N ) 97.3(3), Ge2-
N-C2 ) 118.0(7), N-C2-Ge1 ) 105.1(7), C2-Ge1-O )
95.5(4), Ge1-O-Ge2 ) 117.0(4), Ge2-N-C1 ) 121.9(7),
C1-N-C2 ) 111.4(9), C33-Ge2-C42 ) 110.7(4), C15-
Ge1-C24 ) 112.7(4).
at -78 °C. Warming to room temperature afforded an orange
solution of 1, which is produced in nearly quantitative yield
along with a precipitate of LiF. Crude solutions of 1 were used
without further purification.
Reaction of 1 with PhNCO. To a crude solution of 1 (2.02
mmol) in 15 mL of Et2O was slowly added by syringe at room
temperature 1 equiv of PhNCO (0.22 mL, 2.01 mmol). The
reaction mixture turned from orange to dark orange. After 1
h stirring at room temperature, the lithium salts were
eliminated by filtration and the solvents were removed in
vacuo. Crystallization of the residue from pentane afforded
0.77 g (65%) of white crystals of 2 (mp 225 °C).
Conclusion
This study confirms the high reactivity of germene 1
toward unsaturated compounds and its powerful poten-
tial in organometallic heterochemistry. Other aspects
of the behavior of this building block are under active
investigation.
Anal. Found: C, 76.46; H, 6.11; N, 2.20. Calcd for C38H35-
GeNO: C, 76.80; H, 5.94; N, 2.36. 1H NMR (C6D6): 1.99 (s,
18H, o- and p-Me of Mes), 6.56 (s, 4H, ar H of Mes), 6.92 (td,
3JHH ) 7.4 Hz, 4JHH ) 1.2 Hz, 2H, H2H7 or H3H6) and 7.01-
7.23 (m, 5H, m- and p-H of Ph, H2H7 or H3H6), 7.42, 7.60,
Experimental Section
3
and 7.78 (3d, JHH ) 7.4 Hz, 3 × 2H, o-H of Ph, H1H8 and
General Procedures. All reactions were carried out under
N2 or Ar using standard Schlenk techniques with solvents
freshly distilled from sodium/benzophenone. 1H and 13C NMR
spectra were recorded in CDCl3 on Bruker AC 200, AC 250,
and Avance 300 instruments at 200.13, 250.13, and 300.13
MHz (1H) and 50.10, 62.89, and 75.47 MHz (13C), respectively.
Mass spectra were measured on a Hewlett-Packard 5989 A
spectrometer by EI at 70 eV. Melting points were determined
on a Leitz 250 microscope heating stage. IR spectra were re-
corded on a Perkin-Elmer 1600 FT-IR spectrometer. Elemental
analyses were performed by the “Service de Microanalyse de
l’Ecole de Chimie de Toulouse”.
H4H5). 13C NMR (C6D6): δ 20.57 (p-Me), 23.62 (o-Me), 72.58
(C9), 120.17, 123.69, 125.42, 125.82, 126.92, 128.47 and 128.91
(CH of Ph and CR2), 132.90, 134.32, 140.26, 140.75, 142.63,
and 144.04 (C10-13, ipso-C of Ph, ipso-, o-, and p-C of Mes),
171.55 (CdN). IR (NaCl film): 1690 cm-1 (νCdN). MS (EI, m/z,
%): 595 (M+, 32), 492 (M - PhNC, 3), 476 (Mes2GedCR2, 12),
327 (Mes2GeO - 1, 12), 311 (Mes2Ge - 1, 82), 267 (R2CdCd
NPh, 67), 190 (R2CdCN, 60), 164 (CR2, 100).
Hydrolysis of 2. Water (large excess) was added to a
solution of 2 (0.50 g, 0.84 mmol) in THF. An NMR analysis
showed the complete disappearance of the starting cyclo-
adduct. The new signals observed in the 1H and 13C NMR
spectra were assigned to dioxadigermetane 44 (by comparison
with an authentic sample) and to amide 5. Fractional crystal-
lization afforded 0.18 g (75%) of 5 in 90% purity.
For the 1H and 13C NMR study, the carbon atoms of the
fluorenyl group are numbered as shown in Chart 3.
Synthesis of Germene 1. Germene 1 was prepared as
previously described2 by addition of 1 molar equiv of tert-
butyllithium (1.7 M in pentane) to a solution of the fluoro-
germane Mes2Ge(F)CHR2 (1.00 g, 2.02 mmol) in Et2O (20 mL)
5: 1H NMR (C6D6): δ 4.98 (s, 1H, CHR2), 6.85 (br s, 1H,
3
NH), 7.03 (t, JHH ) 7.3 Hz, 1H, p-H of Ph), 7.24, 7.40, and
7.49 (3t, 3JHH ) 7.3 Hz, 3 × 2H, m-H of Ph, H3H6 and H2H7),
3
(15) (a) Baines, K. M.; Stibbs, W. G. Coord. Chem. Rev. 1995, 145,
157. (b) Holloway, C. E.; Melnik, M. Main Group Met. Chem. 2002,
25, 185.
(16) Gillette, G. R.; Maxka, J.; West, R. Angew. Chem., Int. Ed. Engl.
1989, 28, 54.
(17) Bu¨chi, G.; Ayer, D. E. J. Am. Chem. Soc. 1956, 78, 689.
7.33, 7.77, and 7.84 (3d, JHH ) 7.3 Hz, 3 × 2H, o-H of Ph,
H4H5 and H1H8). 13C NMR (C6D6): δ 57.10 (C9), 119.94,
120.34, 124.51, 125.45, 128.03, 128.68, and 128.87 (CH of Ph
and CR2), 137.38, 141.01, and 141.47 (ipso-C of Ph and C10-
13), 168.77 (CdO).

5368 Organometallics, Vol. 24, No. 22, 2005
Ech-Cherif El Kettani et al.
Reaction of 1 with MeNdCdS. To a crude solution of 1
(2.02 mmol) in Et2O (30 mL) cooled at 0 °C was slowly added
by syringe 0.15 mL of MeNdCdS (2.01 mmol). The reaction
mixture progressively turned brown then orange after 2 h
stirring at room temperature. Solvents were eliminated in
vacuo and replaced by pentane (20 mL). After filtration to
eliminate lithium salts, crystallization at -20 °C afforded 0.77
g (70%) of orange crystals of 3 (mp 185 °C).
Reaction of 1 with MeNO2. To a solution of germene 1
(2.01 mmol) in Et2O (20 mL) cooled at - 78 °C was slowly
added by syringe 0.13 g (2.01 mmol) of MeNO2. The reaction
mixture progressively turned from orange to light yellow by
warming to room temperature. After 4 h stirring, 50 mL of
pentane was added. Lithium salts were filtered off, and
solvents were removed in vacuo. 1H and 13C NMR analysis
showed the formation of 19 and of fluorenone R2CdO; the
latter was identified by comparison with an authentic sample.
Crystallization from Et2O (20 mL) at -20 °C afforded 0.72 g
(65%) of white crystals of 19 (mp 170 °C). Anal. Found: C,
72.38; H, 6.52; N, 1.75. Calcd for C50H55Ge2NO: C, 72.25; H,
6.67; N, 1.69.
Anal. Found: C, 72.42; H, 6.17; N, 2.40. Calcd for C33H33-
1
GeNS: C, 72.29; H, 6.07; N, 2.55. H NMR (C6D6): δ 2.00 (s,
6H, p-Me), 2.11 (s, 12H, o-Me), 3.18 (s, 3H, MeN), 6.57 (s, 4H,
3
4
ar H of Mes), 6.95 and 7.13 (2 td, JHH ) 7.4 Hz, JHH ) 1.2
Hz, 2 × 2H, H2H7 and H3H6), 7.58 and 7.72 (2 d, 3JHH ) 7.4
Hz, 2 × 2H, H1H8 and H4H5). 13C NMR (C6D6): δ 20.50 (p-
Me), 23.68 (o-Me), 41.41 (MeN), 82.15 (C9), 119.81 (C4C5),
124.29, 126.95, and 127.02 (C1-3, C6-8), 129.59 (m-C of Mes),
132.80 (ipso-C of Mes), 139.59, 139.66, 143.06, and 145.47
(C10-13, o- and p-C of Mes), 160.71 (CdN). IR (NaCl film):
1690 cm-1 (νCdN). MS (EI, m/z, %): 549 (M+, 3), 343
(Mes2GedS - 1, 5), 311 (Mes2Ge - 1, 3), 205 (R2CdCdNMe,
67), 190 (R2CdCdN, 100).
19: 1H NMR (CDCl3): δ 1.71 (br s, 12H, o-Me of Mes2Ge
bound to CR2), 2.02 (s, 3H, CH3-N), 2.14 and 2.27 (2s, 2 × 6H,
p-Me), 2.44 (s, 12H, o-Me of Mes2GeN), 6.51 and 6.79 (2s, 2 ×
3
4
4H, arom H of Mes), 6.88 (td, JHH ) 7.6 Hz, JHH ) 1.2 Hz,
3
2H, H2H7 or H3H6), 6.93 (d, JHH ) 7.4 Hz, 2H, H4H5 or
3
4
H1H8), 7.23 (td, JHH ) 7.6 Hz, JHH ) 1.2 Hz, 2H, H3H6 or
H2H7), 7.69 (d, 3JHH ) 7.4 Hz, 2H, H1H8 or H4H5). 13C NMR
(CDCl3): δ 20.79 and 21.04 (p-Me of Mes), 22.84 and 22.94
(o-Me of Mes), 31.82 (MeN), 78.34 (C9), 119.44 (C4C5), 124.51,
125.53 and 126.55 (C1-3, C6-8), 128.54 and 129.34 (m-CH
of Mes), 137.17, 137.38, 138.03, 138.61, 140.55, 142.59, 143.30
and 149.20 (ipso-, o- and p-C of Mes, C10-13). MS (EI, m/z,
%): 831 (M+, 10), 711 (M - Mes - H, 1), 639 (Mes2GeOGeMes2
+ 1, 35), 519 (Mes2GeOGeMes, 15), 399 (MesGeOGeMes - 1,
40), 329 (Mes2GedO + 1, 15), 311 (Mes2Ge - 1, 100), 193
(MesGe and R2CNMe, 90).
Hydrolysis of 3. Hydrolysis of 3 slowly occurred when it
was left at room temperature in an NMR tube in wet solutions
of CDCl3. After 3 days, the signals of 3 disappeared and new
signals assigned to dioxadigermetane 44 and thioamide 6 were
1
observed in the H and 13C NMR spectra.
6: 1H NMR (C6D6): δ 2.27 (d, 3JHH ) 4.8 Hz, 3H, Me), 5.47
(s, 1H, CHR2), 7.05 and 7.16 (2t, 3JHH ) 7.4 Hz, 2 × 2H, H3H6
3
and H2H7), 7.50 and 7.66 (2d, JHH ) 7.4 Hz, 2 × 2H, H4H5
and H1H8). NH was not clearly observed. 13C NMR (C6D6): δ
32.13 (MeN), 64.24 (C9), 119.92 (C4C5), 125.56, 127.81 and
128.41 (C1-3, C6-8), 141.15 and 142.66 (C10-13), 201.96
(CdS). MS (EI, m/z, %): 239 (M+, 80), 208 (R2CCdS, 5), 165
(R2CH, 100), 74 (MeNHCdS, 78).
Crystal Data for 11 and 19. 11: C45H38GeS2, M ) 715.46,
orthorhombic, P212121, a ) 9.484(1) Å, b ) 17.929(2) Å, c )
20.993(2) Å, V ) 3569.4(6) Å3, Z ) 4, T ) 193(2) K; 18 284
reflections (6014 independent, Rint ) 0.0624) were collected.
Largest electron density residue: 0.416 e Å-3, R1 (for I > 2σ(I))
) 0.0440 and wR2 ) 0.0812 (all data) with R1 ) ∑||Fo| - |Fc||/
Reaction of 1 with CS2. To a crude solution of 1 (3.96
mmol) in Et2O (20 mL) cooled at -78 °C was slowly added
CS2 (0.22 g, 3.95 mmol). A violet coloration appeared im-
mediately. After 7 h stirring at room temperature, the lithium
salts were filtered off and the solvents removed in vacuo.
Fractional crystallization in pentane/Et2O (80/20) gave two
products: 12 (1.13 g, white crystals, 83%11) and 11 (0.48 g,
white crystals, 17%, mp 320 °C (dec)). Anal. Found: C, 75.42;
H, 5.19. Calcd for C45H38GeS2: C, 75.54; H, 5.35
∑|Fo| and wR2 ) (∑w(Fo - Fc2)2/∑w(Fo )2)0.5
.
2
2
19: C50H55Ge2NO, M ) 831.14, triclinic, P1h, a ) 9.059(5)
Å, b ) 11.760(6) Å, c ) 19.624(9) Å, R ) 95.90(2)°, â )
97.58(1)°, γ ) 91.71(1)°, V ) 2059.3(17) Å3, Z ) 2, T ) 193(2)
K; 6949 reflections were collected. Largest electron density
residue: 1.429 e Å-3, R1 (for I > 2σ(I)) ) 0.0783 and wR2 )
0.2884 (all data).
All data for both structures represented in this paper were
collected at low temperatures using an oil-coated shock-cooled
crystal on a Bruker-AXS CCD 1000 diffractometer with Mo
KR radiation (λ ) 0.71073 Å). The structures were solved by
direct methods,18 and all non-hydrogen atoms were refined
anisotropically using the least-squares method on F2.19
11: 1H NMR (C6D6): δ 1.98 (s, 6H, p-Me), 2.16 (vbr s, 12H,
o-Me), 6.56 (s, 4H, arom H of Mes), H1-8: CR2 bonded to CS2;
3
H1′-H8′: CR2 bonded to Ge; 6.84 and 6.87 (2 td, JHH ) 7.7
4
3
Hz, JHH ) 1.2 Hz, 2 × 1H, H2H7 or H3H6); 6.86 (d, JHH
)
7.7 Hz, 2H, H1′H8′ or H4′H5′), 7.02 and 7.11 (2 td, 3JHH ) 7.7
4
Hz, JHH ) 1.2 Hz, 2 × 2H, H2′H7′ or H3′H6′), 7.21 and 7.33
Acknowledgment. CMIFM (AI MA/05/123), CNRS,
and French Education Ministery are gratefully acknowl-
edged for financial support of this work.
(2 td, 3JHH ) 7.7 Hz, 4JHH ) 1.2 Hz, 2 × 1H, H3H6 or H2H7),
7.58 (d, 3JHH ) 7.7 Hz, 2H, H4′H5′ or H1′H8′), 7.53, 7.60, 8.44,
and 9.33 (4d, JHH ) 7.7 Hz, 4 × 1H, H1H4 and H5H8). 13C
3
NMR (C6D6): δ 20.51 (p-Me), 23.38 (o-Me), 60.78 (GeCR2),
119.26 and 119.50 (C4C5), 120.11 (C4′C5′), 125.08, 125.90,
126.06, 126.56, 126.96, 128.10, and 129.78 (CH of Mes and
CR2), 132.76, 138.51, 139.12, 139.26, 139.52, 139.97, 140.30,
and 141.54 (S-CdC, C of Mes and C10-13). IR (KBr): ν(CdC)
) 1615 cm-1. MS (EI, m/z, %): 716 (M, 70), 520 (M - R2C -
S, 5), 508 (M - R2CdC-S, 40), 372 (R2CdC-S-CR2, 40), 345
(Mes2GedS + 1, 80), 311 (Mes2Ge - 1, 100).
Supporting Information Available: CIF files for 11 and
19. This material is available free of charge via the Internet
at http://pubs.acs.org.
OM0504607
(18) SHELXS-97: Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467.
(19) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen, 1997.