Varied reactivity of the Germene Mes2Ge=CR2 toward nitriles

Article abstract of DOI:10.1021/om0494622

The germene Mes₂Ge=CR₂ (1, CR₂ = fluorenylidene) shows varied behavior toward nitriles. It reacts as a 1,2-dipole with t-BuCN giving a four-mepibered ring heterocycle, 2-aza-3-germacyclobut-1- ene, as a 1,4-dipole with PhCN, leading to a six-membered ring heterocycle, 3,4-dihydro-3-germaisoquinoline, and as a base, abstracting the α-H of R′CH₂CN to give α-cyanogermanes (R′ = H, 2-thienyl, 2-FC₆H₄, 4-FC₆H₄).

Full text of DOI:10.1021/om0494622

5062
Organometallics 2004, 23, 5062-5065
Va r ied Rea ctivity of th e Ger m en e Mes2GedCR2 tow a r d
Nitr iles
Sakina Ech-Cherif El Kettani,† Mohamed Lazraq,† Henri Ranaivonjatovo,*,‡
J ean Escudie´,‡ Claude Couret,‡ Heinz Gornitzka,‡ and Nathalie Merceron‡
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 04, France
Received J uly 16, 2004
The germene Mes2GedCR2 (1, CR2 ) fluorenylidene) shows varied behavior toward nitriles.
It reacts as a 1,2-dipole with t-BuCN giving a four-membered ring heterocycle, 2-aza-3-
germacyclobut-1-ene, as a 1,4-dipole with PhCN, leading to a six-membered ring heterocycle,
3,4-dihydro-3-germaisoquinoline, and as a base, abstracting the R-H of R′CH2CN to give
R-cyanogermanes (R′ ) H, 2-thienyl, 2-FC6H4, 4-FC6H4).
In tr od u ction
Thus, we became interested in investigating the
reactivity of nitriles with the germene Mes2GedCR2 (1)5
(Mes ) 2,4,6-trimethylphenyl, CR2 ) fluorenylidene),
in which the GedC unsaturation is conjugated with the
fluorenylidene unit. Interestingly, three kinds of prod-
ucts were obtained in this study, depending on the
nitrile used.
The synthesis of the first stable compound containing
a SidC double bond, the silene (Me3Si)2SidC(OSiMe3)-
Ad,1 was a milestone in organometallic chemistry. Other
silenes and some germenes >GedC< and stannenes
>SndC< have been prepared since this date.2 Despite
the great steric hindrance necessary for their stabiliza-
tion as monomers, a flourishing chemistry of these
organometallic alkenes has been developed. Their reac-
tions with various unsaturated compounds showed them
to be, among others, valuable sources of metalated
heterocycles difficult to obtain by other routes. To the
best of our knowledge, in the case of nitriles, only the
[2+4] cycloadduct of the silene Me2SidC(SiMe3)2 with
PhCtN has been reported so far,3a while Me2SidCH2,
generated by pyrolysis of the corresponding silacyclobu-
tane, inserted into a CH bond of acetonitrile.3b Silenes
(Me3Si)2SidC(OSiMe3)R gave a [2+2] cycloadduct with
the CdC bond of acrylonitrile.3c In the case of germenes,
only one recent paper reported the reactions of an
acetylene-bridged bis(germene) with dinitrile com-
pounds.4
Resu lts a n d Discu ssion
Germene 1 reacted at 140 °C as a 1,2-dipole with
trimethylacetonitrile, giving 2-aza-3-germacyclobut-1-
ene (2), a four-membered ring derivative with both a
heavy group 14 element and a CdN double bond6 (eq
1).
The observed regioselectivity (N bonded to germa-
nium) in this [2+2] cycloaddition between the GedC and
CtN unsaturation was expected from the Geδ+dCδ-
polarity of the germanium-carbon double bond. The
structure of 2 was evidenced by mass spectroscopy
(besides the molecular peak, the main fragment was the
starting germene obtained by a [4 f 2+2] cyclorever-
sion) and particularly by NMR spectroscopic analysis
* To whom correspondence should be addressed. E-mail: ranaivon@
chimie.ups-tlse.fr.
† Universite´ Sidi Mohamed Ben Abdellah.
‡ Universite´ Paul Sabatier.
(1) Brook, A. G.; Abdekassen, F.; Gutekunst, B.; Gutekunst, G.;
Kallury, R. K. J . Chem. Soc., Chem. Commun. 1981, 191-192.
(2) For reviews, see: (a) Raabe, G.; Michl, J . The Chemistry of
Organic Silicon Compounds; Patai, S., Rappoport, Z., Eds.; J . Wiley
and Sons: New York, 1989, Chapter 17, pp 1015-1141. (b) Barrau,
J .; Escudie´, J .; Satge´, J . Chem. Rev. 1990, 90, 283-319. (c) Brook, A.
G.; Brook, M. A. Adv. Organomet. Chem. 1996, 39, 71-158. (d) Baines,
K. M.; Stibbs, W. G. Adv. Organomet. Chem. 1996, 39, 275-324. (e)
Mu¨ller, T.; Ziehe, W.; Auner, N. The Chemistry of Organic Silicon
Compounds; Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1998;
Vol. 2, Part 2, Chapter 16, pp 857-1063. (f) Escudie´, J .; Couret, C.;
Ranaivonjatovo, H. Coord. Chem. Rev. 1998, 178-180, 565-592. (g)
Escudie´, J .; Ranaivonjatovo, H. Adv. Organomet. Chem. 1999, 44, 113-
174. (h) Weidenbruch, M. J . Organomet. Chem. 2002, 646, 39-52.
(3) (a) Wiberg, N.; Preiner, G.; Schieda, O. Chem. Ber. 1981, 114,
3518-3532. (b) Bush, R. D.; Golino, C. M.; Roark, D. N.; Sommer, L.
H. J . Organomet. Chem. 1973, 59, C17-C20. (c) Brook, A. G.; Hu, S.
S.; Saxena, A. K.; Lough, A. J . Organometallics 1991, 10, 2758-2767.
(4) Meiners, F.; Haase, D.; Koch, R.; Saak, W.; Weidenbruch, M.
Organometallics 2002, 21, 3990-3995.
(5) (a) Couret, C.; Escudie´, J .; Satge´, J .; Lazraq, M. J . Am. Chem.
Soc. 1987, 109, 4411-4412. (b) Lazraq, M.; Escudie´, J .; Couret, C.;
Satge´, J .; Dra¨ger, M.; Dammel, R. Angew. Chem., Int. Ed. Engl. 1988,
27, 828-829.
(6) Rather similar 1-aza-2,3-disilacyclobut-1-enes have been ob-
tained by thermolysis or photolysis of cyclotrisilanes (R2Si)3 in the
presence of nitriles. Although in a formal sense they are the product
of a [2+2] cycloaddition reaction between the disilene R2SidSiR2 and
a nitrile, their formation is likely to proceed via initially generated
azasilacyclopropenes followed by ring expansion with a second silylene
R2Si: (a) Weidenbruch, M.; Meiners, F.; Saak, W. Can. J . Chem. 2000,
78, 1469-1473. (b) Belzner, J .; Ihmels, H.; Noltemeyer, M. Tetrahedron
Lett. 1995, 36, 8187-8190.
10.1021/om0494622 CCC: $27.50 © 2004 American Chemical Society
Publication on Web 09/09/2004

Varied Reactivity of Mes2GedCR2 toward Nitriles
Organometallics, Vol. 23, No. 21, 2004 5063
Sch em e 1
1
(δ 13C (CdN) ) 198.41 ppm). In the H NMR spectrum,
a very broad singlet, characteristic of a cyclic structure,7
was observed for the ortho-methyl groups of equivalent
mesityl groups due to their slow rotation caused by the
large steric hindrance, which confers to 2 a surprisingly
high thermal stability.
The structure of 2 was confirmed chemically by its
hydrolysis, which gave a nearly quantitative yield of
tetramesityldigermoxane (3)8 and fluorenyl(tert-butyl)-
ketone (4).9 Their formation resulted from the initial
cleavages of the Ge-C and Ge-N bonds, giving first the
dihydroxygermane 58a,10 (which slowly converts to 3)
and the transient imine 6 (δ 13C NMR (CdN) ) 189.1
ppm), which undergoes further hydrolysis to 4 (Scheme
1).
F igu r e 1. Molecular structure of 7 with thermal ellipsoids
drawn at the 50% probability level. Hydrogen atoms are
omitted for clarity. Selected bond lengths (Å) and angles
(deg): Ge1-N1, 1.855 (4); C1-N1, 1.306(6); Ge1-C30,
1.979(4); Ge1-C21, 1.964(5); Ge1-C14, 1.990(5); C13-C14,
1.516(6); C8-C13, 1.395(6); C1-C8, 1.496(7); N1-Ge1-
C14, 98.74(19); N1-Ge1-C21, 101.16(19); N1-Ge1-C30,
111.19(17); C21-Ge1-C30, 112.6(2); C1-N1-Ge1,
122.8(3); N1-C1-C8, 124.5(4).
The behavior of 1 toward benzonitrile is completely
different, giving compound 7 (eq 2). The structure of 7
was established by an X-ray diffraction (Figure 1).
In contrast, with nitriles of type R′CH2CtN with R′
groups of various electronic effects, 1 preferentially
reacted at the hydrogen R to the CtN bond. These
reactions occurred at room temperature in Et2O solu-
tions to afford R-cyanogermanes 9a -d in quantitative
yield, regioselectively with exclusive formation of the
GeCH(R′)CtN moiety as expected from the Geδ+dCδ-
polarity (eq 3). Thus germene 1 contains a strongly basic
fluorenylidene unit.
The first step of the reaction probably was the
formation of 8 by [2+4] cycloaddition between the
CtN moiety and the GedC-CdC dienic system of 1,
followed by rearomatization via a 1,3-sigmatropic shift
of H, leading to 3,4-dihydro-3-germaisoquinoline (7).
This a priori surprising diene behavior of 1 can, how-
ever, be understood both from its cisoid structure and
from the conjugation of the GedC double bond with the
fluorenylidene unit.11 Usually, one of the features of
Diels-Alder reactions with nitriles as dienophiles is the
extremely high reaction temperature required, often
above 200 °C.12 Therefore, the formation of 7 in 78%
yield at room temperature was rather unexpected and
confirmed the high reactivity of 1.
Such electrophilic addition of acidic HA compounds
to the GedC double bond of 1 has previously been
reported to occur only with the more “acidic” hydrogens
of alcohols, water, thiols, and imines containing an NH
bond to give Mes2Ge(A)C(H)R2 adducts.5a,13
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were carried out
(7) In the four-membered ring 1-oxa-2-germacyclobutane, obtained
from 1 and benzophenone, a similar very broad signal was observed
for the ortho-methyl groups of the mesityl substituents: Lazraq, M.;
Couret, C.; Escudie´, J .; Satge´, J .; Dra¨ger, M. Organometallics 1991,
10, 1771-1778.
under N2 or Ar using standard Schlenk techniques with
1
solvents freshly distilled from sodium benzophenone. H and
13C NMR spectra were recorded in CDCl3 on a Bruker AC 250
instrument at 250.1 MHz and a Bruker Avance 300 instrument
at 75.48 MHz, respectively. Mass spectra were measured on
a Hewlett-Packard 5989 A spectrometer by EI at 70 eV.
Melting points were determined on a Leitz microscope heating
stage 250. IR were recorded on a Perkin-Elmer 1600 FT-IR
spectrometer. Elemental analyses were performed by the
“Service de Microanalyse de l’Ecole de Chimie de Toulouse”.
The carbon atoms of the fluorenyl group are numbered as
shown in Figure 1.
(8) (a) Duverneuil, G.; Mazerolles, P.; Perrier, E. Appl. Organomet.
Chem. 1994, 8, 119-127. (b) Samuel, M. S.; J ennings, M. C.; Baines,
K. M. J . Organomet. Chem. 2001, 636, 130-137.
(9) 1H NMR data were in accordance with those found in: Meyers,
C. Y.; Wahner, A. P.; Manohar, S. K.; Carr, S. E.; Chan-Yu-King, R.;
Robinson, P. D. Acta Crystallogr. 1991, C47, 1236-1239.
(10) Slow decomposition of 5 to 3 was observed previously: (a) El
Baz, F.; Rivie`re-Baudet, M.; Chazalette, C.; Gornitzka, H. Phosphorus,
Sulfur Silicon 2000, 163, 121-142. (b) Rivie`re-Baudet, M.; El Baz, F.;
Satge´, J .; Khallaayoun, A.; Ahra, M. Phosphorus, Sulfur Silicon 1996,
112, 203-217.
(11) The unique precedent diene behavior of 1 was postulated in
its reaction with t-BuCtP at 170 °C: Lazraq, M.; Escudie´, J .; Couret,
C.; Bergstra¨sser, U.; Regitz, M. Chem. Commun. 1993, 569-570.
(12) Hamer, J . 1,4-Cycloaddition Reactions; Academic Press: New
York, 1967; pp 97-125.
Syn th esis of 2. Germene 1 was prepared as previously
described5 by addition of 1 molar equiv of tert-butyllithium (1.7
(13) Lazraq, M.; Escudie´, J .; Couret, C.; Satge´, J .; Soufiaoui, M.
Organometallics 1991, 10, 1140-1143.

5064 Organometallics, Vol. 23, No. 21, 2004
Ech-Cherif El Kettani et al.
M in pentane) to a solution of the fluorogermane Mes2Ge(F)-
CHR2 (1.00 g, 2.02 mmol) in Et2O (20 mL) cooled at -78 °C.
Warming to room temperature afforded an orange solution of
1, which is nearly quantitatively produced along with a
precipitate of LiF. Crude solutions of 1 were used without
further purification. The mixture of Mes2GedCR2 and t-BuCN
(0.17 g, 2.02 mmol) was heated in a sealed tube at 140 °C for
15 h. After filtration to remove LiF and evaporation of solvents
in vacuo, crystallization from pentane at -20 °C afforded 0.54
g of 2: white crystals; mp 228 °C; yield 48%; 1H NMR (CDCl3)
δ 0.83 (s, 9H, t-Bu), 2.01 (br s, 12H, o-Me), 2.24 (s, 6H, p-Me),
- Ph, 17). Anal. Calcd for C38H35GeN: C, 78.93; H, 6.10.
Found: C, 78.75; H, 6.05.
Cr ysta l d a ta for 7: C38H35GeN, M ) 578.26, monoclinic,
P21/ c, a ) 11.701(3) Å, b ) 15.722(4) Å, c ) 16.171(4) Å, â )
91.083(4)°, V ) 2974.3(12) Å3, Z ) 4, T ) 193(2) K. 11 756
reflections (4208 independent, Rint ) 0.1054) 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 structure was solved by direct
methods (SHELXS-97),14 and all non hydrogen atoms were
refined anisotropically using the least-squares method on F2.15
Largest electron density residue: 0.683 e Å-3, R1 (for I > 2σ-
3
6.75 (s, 4H, arom CH of Mes), [7.01 (d, J HH ) 7.6 Hz, 2H),
3
3
7.10 and 7.33 (2t, J HH ) 7.6 Hz, 2 × 2H), 7.85 (d, J HH ) 7.6
Hz, 2H), H of CR2]; 13C NMR (CDCl3) δ 20.98 (p-Me), 23.20
(o-Me), 28.68 (C(CH3)3), 42.79 (C(CH3)3), 73.77 (CR2), 120.03,
123.80, 125.89 and 126.42 (CH of CR2), 126.70 (m-CH of Mes),
132.90 (ipso-C of Mes), 138.30, 139.50, 143.39, and 144.38 (o-
and p-C of Mes, quat. C of CR2), 198.41 (CdN); IR (KBr) 1542.0
cm-1 (νCdN); MS, m/z (%) 559 (M, 4), 502 (M - t-Bu, 2), 476
(Mes2GedCR2, 42), 440 (M - Mes, 2), 311 (Mes2Ge - 1, 100),
192 (MesGe - 1, 38). Anal. Calcd for C36H39GeN: C, 77.45; H,
7.04. Found: C, 77.21; H, 7.25.
(I)) ) 0.0488 and wR2 ) 0.0972 (all data) with R1 ) ∑||Fo| -
2
|Fc||/∑|Fo| and wR2 ) (∑w(Fo - Fc2)2/∑w(Fo2)2)0.5
.
Rea ction of Mes2GedCR2 w ith Nitr iles R′CH2CtN:
F or m a tion of r-Cya n oger m a n es 9. To a crude solution of
1 prepared as previously described5 from 1.00 g (2.02 mmol)
of Mes2Ge(F)CHR2 in Et2O (20 mL) cooled at -78 °C was added
1 equiv of the nitrile R′CH2-CtN. The reaction mixture was
allowed to warm to room temperature, during which time it
slowly turned from orange to pale yellow. After overnight
stirring, solvent was removed in vacuo and replaced by 15 mL
of pentane. Crystallization at -20 °C afforded pure 9a -d as
crystalline compounds.
Hyd r olysis of 2. Compound 2 slowly hydrolyzed when left
in wet CDCl3 solution at room temperature. After 3 days, the
NMR signals of 2 disappeared and new signals assigned to
1
9a : white crystals; 0.96 g, yield 92%; mp 142-143 °C; H
1
dihydroxygermane 5 and imine 6 were observed in the H and
NMR (CDCl3) δ 1.64 (s, 3H, CH2), 2.11 (s, 12H, o-Me), 2.27 (s,
6H, p-Me), 5.10 (s, 1H, CHR2), 6.81 (s, 4H, arom H of Mes),
13C NMR spectra.
3
3
1
[7.15 (d, J HH ) 7.6 Hz, 2H), 7.18 and 7.35 (2t, J HH ) 7.6 Hz,
5: H NMR (CDCl3) δ 1.84 (s, 2H, OH), 2.28 (s, 6H, p-Me),
2 × 2H), 7.83 (d, J HH ) 7.6 Hz, 2H), CR2]; 13C NMR (CDCl3)
3
2.45 (s, 12H, o-Me), 6.83 (s, 4H, arom. H); 13C NMR (CDCl3) δ
21.12 (p-Me), 23.14 (o-Me), 129.32 (m-C), 133.20 (ipso-C),
140.08 (p-C), 143.10 (o-C).
δ 6.19 (CH2), 20.92 (p-Me), 24.20 (o-Me), 43.81 (CHR2), 119.43
(CtN), 119.76, 125.12, 126.38, and 126.68 (CH of CR2), 129.69
(m-CH of Mes), 133.35, 139.13, 140.74, 142.64, and 143.55
(ipso-, o- and p-C of Mes and quat. C of CR2); IR (KBr) 2232
cm-1 (νCtN); MS, m/z (%) 517 (M, 1), 477 (M - CH2CN, 3),
352 (M - CHR2, 85), 311 (Mes2Ge - 1, 15), 192 (MesGe - 1,
20), 165 (CHR2, 100). Anal. Calcd for C33H33GeN: C, 76.78;
H, 6.44. Found: C, 77.02; H, 6.55.
6: 1H NMR (CDCl3) δ 1.49 (s, 9H, t-Bu), 5.09 (s, 1H, CHR2),
3
3
[7.26 (t, J HH ) 7.6 Hz, 2H), 7.35 (d, J HH ) 7.6 Hz, 2H), 7.38
(t, J HH ) 7.6 Hz, 2H), 7.78 (d, J HH ) 7.6 Hz, 2H), CR2]; 13C
NMR (CDCl3) δ 27.98 (C(CH3)3), 40.78 (C(CH3)3), 52.78 (CR2),
120.08, 124.34, 127.53 and 127.71 (CH of CR2), 140.10 and
142.00 (quat. C of CR2), 189.08 (CdN).
3
3
1
9b: white crystals; 1.01 g, yield 82%; mp 145 °C; H NMR
5 and 6 were not isolated. After 2 weeks, NMR analysis of
this solution showed the nearly quantitative formation of 38
and 4.
3: 13C NMR (CDCl3) δ 21.12 (p-Me), 23.14 (o-Me), 129.32
(m-C of Mes), 133.20 (ipso-C), 140.08 (p-C of Mes), 143.10 (o-C
of Mes).
4 was also identified by an independent synthesis.9 13C NMR
(CDCl3) δ 26.57 (CMe3), 45.64 (CMe3), 57.11 (HCR2), 120.36,
124.43, 127.32 and 127.81 (CH of CR2), 142.38 and 143.60
(quat. C of CR2), 213.18 (CO); MS (EI, m/z, %) 250 (M, 10),
192 (M - t-Bu -1, 3), 165 (R2CH, 30), 57 (t-Bu, 100).
(CDCl3) δ 1.69 and 2.03 (2s, 2 × 6H, o-Me), 2.10 and 2.24 (2s,
2 × 3H, p-Me), 4.96 (s, 1H, CH-CtN), 5.11 (s, 1H, CHR2),
6.39 and 6.68 (2s, 2 × 2H, arom H of Mes), 6.69-8.15 (m, 12H,
arom H of C6H4F and CR2); 13C NMR (CDCl3) δ 20.71 and 20.86
3
(p-Me), 23.57 (d, J CF )1.1 Hz, CHCtN), 24.38 and 24.90 (o-
Me), 46.67 (d, 5J CF )1.5 Hz, CHR2), 114.90 (d, 2J CF ) 21.9 Hz,
2
CH-CF), 119.75 and 119.76 (CH of CR2), 121.96 (d, J CF
)
15.1 Hz, ipso-C of C6H4F), 122.26 (CtN), 124.27 (d, J CF ) 3.3
Hz, CH of C6H4F), 124.68, 124.81, 124.94, 126.04, 126.21,
126.36, 128.65, and 129.48 (m-CH of Mes and CH of CR2),
128.39 (d, J CF ) 8.3 Hz, CH of C6H4F), 131.00 (d, J CF ) 3.5
Hz, CH of C6H4F), 130.92, 132.81, 138.16, 138.71, 141.29,
141.58, 142.78, 143.42, 143.69, and 144.43 (ipso-, o-, and p-C
Syn th esis of 7. One equivalent of PhCN (0.21 g, 2.02 mmol)
was added to a solution of 1, prepared as previously described,5
cooled at -78 °C. The reaction mixture gradually turned from
orange to light yellow after overnight stirring at room tem-
perature. LiF was then filtered, and the solvents were removed
in vacuo. Recrystallization of the crude material from pentane
at -20 °C afforded white crystals of 7 (0.91 g, yield 78%, mp
200-201 °C): 1H NMR (C6D6) δ 1.85 (s, 3H, p-Me), 1.97 (br s,
6H, o-Me), 2.15 (s, 3H, p-Me), 2.52 (s, 6H, o-Me), 4.55 (s, 1H,
CH-Ge), 6.43 and 6.81 (2s, 2 × 2H, arom H of Mes), 7.10-
7.29 (m, 7H, m- and p-H of C6H5 and 4H of CR2), 7.51, 7.71,
1
of Mes and quat. C of CR2), 159.67 (d, J CF ) 244.5 Hz, CF);
19F NMR (CDCl3) δ -39.0; MS, m/z (%) 477 (Mes2GeCHR2, 2),
446 (M - CHR2, 4), 312 (Mes2Ge, 10), 192 (MesGe - 1, 41),
165 (CHR2, 100). Anal. Calcd for C39H36FGeN: C, 76.75; H,
5.95. Found: C, 76.51; H, 6.05.
1
9c: white crystals; 1.06 g, yield 86%; mp 248 °C; H NMR
(CDCl3) δ 1.78 and 1.85 (2s, 2 × 6H, o-Me), 2.15 and 2.20 (2s,
2 × 3H, p-Me), 4.70 (s, 1H, CH-CtN), 5.18 (s, 1H, CHR2),
6.48 and 6.60 (2s, 2 × 2H, arom H of Mes), 6.82-8.01 (m, 12H,
arom H of C6H4F and CR2); 13C NMR (CDCl3) δ 20.78 and 20.82
(p-Me), 24.79 and 24.98 (o-Me), 29.2 (CHCtN), 45.84 (CHR2),
115.36 (d, 2J CF ) 21.1 Hz, m-CH of C6H4F), 119.97 and 120.00
(CH of CR2), 122.66 (CtN), 124.32, 124.82, 125.84, 125.91,
126.18, 129.01, 129.37, 129.69, and 129.79 (m-CH of Mes, CH
of CR2, o-CH of C6H4F), 130.03, 131.40, 131.80, 138.54, 138.72,
141.45, 142.98, 143.23, 143.91, and 144.15 (ipso-, o-, and p-C
3
and 7.81 (3d, J HH ) 7.6 Hz, 3 × 1H, 3H of CR2), 7.88-7.92
(m, 2H, o-H of C6H5); 13C NMR (C6D6) δ 20.42 and 20.75 (p-
Me), 22.80 and 24.68 (o-Me), 41.25 (CHR2), 120.43, 121.20,
124.44, 125.95, 126.37, 126.90, 127.36 (CH of CR2), 127.68,
128.00, 128.52, and 129.08 (m-CH of Mes, o- and m-CH of Ph),
129.16 (p-CH of Ph), 129.81, 135.47, 136.05, 138.55, 138.75,
141.15, 141.20, 141.96, 142.25, 143.25, 143.99, and 145.47
(ipso-C of Ph, ipso-, o-, and p-C of Mes, C12,13,15,16), 171.35
(CdN); IR (KBr) 1556 cm-1 (νCdN); MS, m/z (%) 579 (M, 9),
564 (M - Me, 3), 460 (M - Mes, 3), 341 (M - 2Mes, 10), 311
(Mes2Ge - 1, 100), 267 (M - Mes2Ge, 18), 190 (M - Mes2Ge
(14) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467-473.
(15) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen, 1997.

Varied Reactivity of Mes2GedCR2 toward Nitriles
Organometallics, Vol. 23, No. 21, 2004 5065
of Mes, quat. C of CR2, ipso-C of C6H4F), 161.78 (d, 1J CF ) 246.0
Hz, CF); 19F NMR (CDCl3) δ -39.9; MS, m/z (%) 477 (Mes2-
GeCHR2, 19), 446 (M - CHR2, 45), 312 (Mes2Ge, 14), 192
143.55, 143.96, and 144.31 (quat. C of CR2, ipso-, o- and p-C
of Mes); IR (KBr) 2222.7 cm-1 (νCtN); MS, m/z (%) 477 (Mes2-
GeCHR2, 30), 434 (M - CHR2, 22), 311 (Mes2Ge - 1, 23), 192
(MesGe - 1, 48), 165 (CHR2, 100). Anal. Calcd for C39H36
-
(MesGe - 1, 41), 165 (CHR2, 100). Anal. Calcd for C37H35-
FGeN: C, 76.75; H, 5.95. Found: C, 77.01; H, 5.80.
GeNS: C, 74.27; H, 5.90. Found: C, 74.50; H, 6.02.
9d : light pink crystals; 0.95 g, yield 79%; mp 255 °C; 1H
NMR (CDCl3) δ 1.76 and 1.96 (2s, 2 × 6H, o-Me), 2.14 and
2.21 (2s, 2 × 3H, p-Me), 4.91 (s, 1H, CHR2), 5.31 (s, 1H, CH-
CtN), 6.46 and 6.64 (2s, 2 × 2H, arom H of Mes), 6.50-8.01
(m, 11H, arom H of thienyl and CR2); 13C NMR (CDCl3) δ 20.85
(CHCtN), 20.94 and 24.47 (p-Me), 25.06 and 25.32 (o-Me),
46.19 (CHR2), 97.54 (CtN), 119.94 and 120.23 (CH of CR2),
121.83 (CSCH) 123.95, 124.45, 124.77, 126.04, 126.12, 126.41,
127.25, and 127.64 (CH of CR2 and thienyl), 129.01 and 129.50
(m-CH of Mes), 131.11, 135.02, 138.47, 138.74, 141.40, 143.13,
Ack n ow led gm en t. Financial support of this work
by the CMIFM (AI 00/216/SM) is gratefully acknowl-
edged.
Su ppor tin g In for m ation Available: Table of bond lengths
and bond angles for 7. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM0494622