Reaction of tin(II) hydride with compounds containing aromatic C-F bonds

Article abstract of DOI:10.1021/om1000106

The reaction of the stable tin(II) hydride LSnH (1; L = CH{(CMe) ₂(2,6-iPr₂C₆H₃N)₂}) with fluorinated aromatic compounds is described. The reaction of 1 with equivalent amounts of pentafluorobenzophen

Full text of DOI:10.1021/om1000106

Organometallics 2010, 29, 4837–4841 4837
DOI: 10.1021/om1000106
Reaction of Tin(II) Hydride with Compounds Containing
Aromatic C-F Bonds†
Anukul Jana,‡ Herbert W. Roesky,*,‡ Carola Schulzke,§ and Prinson P. Samuel‡
‡
€
Institut fu€r Anorganische Chemie der Universitat Gottingen, Tammannstrasse 4, 37077 Gottingen, Germany,
€
€
and §School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
Received January 5, 2010
The reaction of the stable tin(II) hydride LSnH (1; L=CH{(CMe)2(2,6-iPr2C6H3N)2}) with fluori-
nated aromatic compounds is described. The reaction of 1 with equivalent amounts of pentafluoro-
benzophenone (PhCOC6F5) and perfluorobenzophenone (C6F5COC6F5), respectively, in toluene at
room temperature, leads to the nucleophilic addition products LSnOCHPh(C6F5) (3) and LSnOCH-
(C6F5)2 (4) as well as to metathesis products PhCO(4-C6F4H) (5) and C6F5CO(4-C6F4H) (6) with
the formation of LSnF (2). In contrast, the reactions of 4-fluorobenzophenone (PhCO-4-C6H4F)
and pentafluorobenzaldehyde (C6F5CHO) with 1 provide the tin(II) alkoxide products LSnO-
CHPh(4-C6H4F) (7) and LSnOCH2C6F5 (8) as a result of nucleophilic addition of hydride to the
carbonyl group. Moreover, 1 was treated with C6F6 in C6D6 at room temperature and after 24 h the
1H, 19F, and 119Sn NMR spectra were recorded, which indicated the appearance of LSnF (2), C6F5H
(9), and LSnC6F5 (10). Formation of compound 10 was further confirmed by its synthesis from
LSnCl and C6F5Li.
Introduction
Consequently we became interested in the activation of
carbon-fluorine bonds by group 14 hydrides, because one of
our research topics involves compounds of group 14 with low-
valent and low-coordinate elements.5 To the best of our know-
ledge, the hydrodefluorination by group 14 elements was only
reported by Ozerov et al. in 2008 using silylium-carborane
catalysts in the presence of silicon(IV) hydride.6 Herein we
present our results on the selective breaking of aromatic C-F
bonds by the Sn-H bond of LSnH (1).7
The breaking of carbon-fluorine bonds is one of the most
significant challenges in chemistry, because carbon-fluorine
bonds are among the most unreactive single bonds in chem-
istry,1 in spite of the fact that fluorine-containing molecules
are important in pharmaceutical, agrochemical, and materi-
als science.2 From a thermodynamic point of view, the C-F
bond is the strongest single bond to carbon, and also from
a kinetic perspective organic fluorides are modest substrates
for nucleophilic substitution reactions or oxidative addi-
tion to low-valent metal centers. In the literature, there are
numerous reports on the catalytic C-F bond activation of
fluorinated compounds by transition-metal catalysts in the
presence of silicon(IV) hydride.3 However, their selective
activation and transformation under mild conditions are
scarcely known. In 2005, Andersen and co-workers repor-
ted the hydrogen for fluorine exchange by cerium hydride.4
Results and Discussion
In a previous communication we have already discussed
the nucleophilic addition reaction of LSnH (1) with com-
pounds containing the trifluoroacetyl group (2,2,2-trifluoro-
acetophenone and 2,2,2-trifluoroacetothiophane).8 There
were no indications that the aliphatic C-F bonds show a
metathesis reaction with the Sn-H bond. Moreover, it is worth
mentioning that an analogous reaction occurred when these
fluorinated compounds were treated with LGeH.9 Compound
† Part of the Dietmar Seyferth Festschrift.
*To whom correspondence should be addressed. Fax: þ49-551-
393373. E-mail: hroesky@gwdg.de.
(1) Hudlicky, M. Chemistry of Organic Fluorine Compounds; Prentice
Hall: New York, 1992.
(5) (a) Jana, A.; Ghoshal, D.; Roesky, H. W.; Objartel, I.; Schwab,
G.; Stalke, D. J. Am. Chem. Soc. 2009, 131, 1288–1293. (b) Jana, A.; Sen,
S. S.; Roesky, H. W.; Schulzke, C.; Dutta, S.; Pati, S. K. Angew. Chem. 2009,
121, 4310-4312; Angew. Chem., Int. Ed. 2009, 48, 4246-4248. (c) Jana,
A.; Schulzke, C.; Roesky, H. W. J. Am. Chem. Soc. 2009, 131, 4600–4601.
(d) Nagendran, S.; Roesky, H. W. Organometallics 2008, 27, 457–492.
(6) Douvris, C.; Ozerov, O. V. Science 2008, 321, 1188–1190.
(7) Pineda, L. W.; Jancik, V.; Starke, K.; Oswald, R. B.; Roesky,
H. W. Angew. Chem. 2006, 118, 2664-2667; Angew. Chem., Int. Ed.
2006, 45, 2602-2605.
(2) (a) Filler, R.; Kobayashi, Y.; Yagupolskii, Y. L. Organofluoride
Compounds in Medicinal Chemistry and Biological Applications; Elsevier:
Amsterdam, The Netherlands, 1993. (b) Ma, J.-A.; Cahard, D. Chem. Rev.
2004, 104, 6119–6146. (c) Hiyama, T. Organofluorine Compounds Chem-
istry and Applications; Springer: New York, 2000.
(3) (a) Vela, J.; Smith, J. M.; Yu, Y.; Ketterer, N. A.; Flaschenriem,
C. J.; Lachicotte, R. J.; Holland, P. L. J. Am. Chem. Soc. 2005, 127,
€
€
7857–7870. (b) Braun, T.; Wehmeier, F.; Altenhoner, K. Angew. Chem.
(8) (a) Jana, A.; Roesky, H. W.; Schulzke, C.; Doring, A. Angew.
2007, 119, 5415-5418; Angew. Chem., Int. Ed. 2007, 46, 5321-5324.
(c) Reade, S. P.; Mahon, M. F.; Whittlesey, M. K. J. Am. Chem. Soc. 2009,
131, 1847–1861.
(4) Maron, L.; Werkema, E. L.; Perrin, L.; Eisenstein, O.; Andersen,
R. A. J. Am. Chem. Soc. 2005, 127, 279–292.
Chem. 2009, 121, 1126-1129; Angew. Chem., Int. Ed. 2009, 48,
1106-1109. (b) Jana, A.; Roesky, H. W.; Schulzke, C. Inorg. Chem. 2009,
48, 9543–9548.
(9) Jana, A.; Roesky, H. W.; Schulzke, C. Dalton Trans. 2010, 39,
132–138.
r
2010 American Chemical Society
Published on Web 04/13/2010
pubs.acs.org/Organometallics

4838 Organometallics, Vol. 29, No. 21, 2010
Scheme 1. Preparation of Compounds 2-6
Jana et al.
1 reacts with equivalent amounts of pentafluorobenzophenone
(PhCOC6F5) and perfluorobenzophenone (C6F5COC6F5), res-
pectively, in toluene at room temperature with the formation of
products 2-6 (Scheme 1). This is shown from the 1H, 19F, and
119Sn NMR spectra. One of these species is the metathesis
product LSnF (2),10 obtained by cleavage one of the C-F
bonds, and the others are the addition products LSnOCH-
(C6F5)Ph (3) and LSnOCH(C6F5)2 (4), which are obtained by
nucleophilic hydride addition to the respective carbonyl group.
The formation of LSnF (2) and the alkoxide product ratio
of 3 and 4 are calculated by integration of the resonances in
the respective 119Sn NMR spectrum. In the case of the
reaction between LSnH (1) and pentafluorobenzophenone,
the product ratio is 1.0:0.6, and the 119Sn NMR resonance
arises at δ -217 ppm for the compound LSnOCH(C6F5)Ph
(3), and the other one is the doublet for LSnF (2) (δ -371.5
Figure 1. Selected region of the 1H NMR spectrum of com-
pound 6, showing the triplet of triplets with coupling constants
of 3J(F-H)=9.56 Hz and 4J(F-H) =7.45 Hz.
Scheme 2. Preparation of Compounds 7 and 8
2
ppm, J(Sn-F) = 3100 Hz). The latter resonance matches
well with that of freshly prepared 2 from the reaction of LSn-
Me with Me3SnF.10 For perfluorobenzophenone, the pro-
duct ratio is 1.0:0.8, with a 119Sn chemical shift (δ -252 ppm)
for LSnOCH(C6F5)2 (4). The 1H NMR spectrum of 4 shows
a singlet (δ 4.77 ppm) for the γ-CH protons and two septets
(δ 3.46 and 3.02 ppm) corresponding to the two different
types of CHprotons of the iPr moieties. All the other resonances
are as expected. In the 1H NMR spectrum the quaternary
proton from the LSn-O-CH moiety appears as a singlet
at δ 6.41 and 6.72 ppm for 3 and 4, respectively, which is
comparable with those of analogous compounds.8 In the EI
mass spectrum of 4, the molecular ion peak is observed at m/z
900 as the base peak. Moreover, there are no indications that the
tin(II) alkoxide products 3 and 4 react further with 1 as a result
of fluorine exchange with the aromatic skeleton.
Subsequently, we have selected the substrates 4-fluoro-
benzophenone (PhCO4-C6H4F) and pentafluorobenzalde-
hyde (C6F5CHO) for a better understanding of the reactivity
of LSnH (1). The reaction of 1 with 4-fluorobenzophenone
leads exclusively to the nucleophilic addition product
LSnOCHPh(4-C6H4F) (7) (Scheme 2). There are no indica-
tions that the para fluorine atom is replaced. The 1H NMR
spectrum of 7 exhibits a singlet (δ 5.15 ppm) which corre-
sponds to the quaternary CH proton, and the other reso-
nances are as expected.8 In the 19F NMR spectrum of 7, the
resonance occurs at δ -112.3 ppm as a multiplet. In the
119Sn NMR spectrum, the resonance of 7 exhibits a singlet
(δ -212 ppm), which is similar to that of LSnOCHPh2
(δ -218 ppm).8b In the EI mass spectrum the molecular ion
peak was observed at m/z 737 with 90% intensity and the base
peak occurs at m/z 652 for [Mþ - C6H4F] with 100% intensity.
Treatment of 1 with pentafluorobenzaldehyde leads quan-
titatively to the stannylene alkoxide LSnOCH2C6F5 (8),
with a SnII-O-CH2 framework that is formed by nucleo-
philic hydride addition to the carbon of the carbonyl group
(Scheme 2).
Therefore, LSnF (2) can only be formed from the fluorine
exchange of pentafluorobenzophenone (PhCOC6F5) and
perfluorobenzophenone (C6F5COC6F5). In addition, we
1
found in both H NMR spectra that there is a triplet of
triplets (δ 6.18 and 6.08 ppm) present with coupling con-
stants of 3J(F-H) = 9.65 Hz and 4J(F-H) =7.30 Hz for 5
and 3J(F-H) = 9.56 Hz and and 4J(F-H) =7.45 Hz for 6
(Figure 1). According to the values of chemical shifts and on
the basis of the coupling constant, we conclude that this is
due to the selective breaking of the para carbon-fluorine
bond, leading to the formation of the two new compounds
PhCO(4-C6F4H) (5) and C6F5CO(4-C6F4H) (6).11 Unfortu-
nately, we cannot assign the 19F chemical shifts, because the
resonances overlap with each other. Only in the case of 2
were we able to assign the 19F NMR spectrum Sn-F reso-
nance at δ -125.29 ppm, which is flanked by satellite peaks
attributable to J(19F-119Sn)=3100 Hz and J(19F-117Sn)=
2955 Hz.
Compound 8 is a yellow solid, soluble in benzene, THF,
n-hexane, and n-pentane, and shows no decomposition on
exposure to air. The 1H NMR spectrum of 8 exhibits a singlet
(δ 4.81 ppm) which can be assigned to the CH2 protons
and is flanked by Sn satellite lines (3J(119Sn-1H)=13.5 Hz).
The 119Sn NMR resonance of 8 arises at δ -262 ppm. 8
crystallizes in the triclinic space group P1 with one mono-
mer in the asymmetric unit (Figure 2). The Sn-O bond
˚
length (2.030(1) A) is comparable with that of compound
8a
˚
LSnOCH2Fc (2.025(1) A). The O-C bond distances of 8
and LSnOCH2Fc are very similar (1.404(2) and 1.411(2) A).
8a
˚
From the above reactions we can argue that there is a com-
petition between the metathesis reaction and the nucleophilic
addition reaction. The ortho and para C-F bonds are activa-
ted in pentafluorobenzophenone and perfluorobenzophenone.
Most probably due to steric reasons, the selective C-F bond
€
(10) Jana, A.; Roesky, H. W.; Schulzke, C.; Doring, A.; Beck, T.; Pal.,
A.; Herbst-Irmer, R. Inorg. Chem. 2009, 48, 193–197.
(11) Berger, S.; Braun, S.; Kalinowski, H.-O. NMR Spectroscopy of
the Non-Metallic Elements; Wiley: West Sussex, England, 1996.

Article
Organometallics, Vol. 29, No. 21, 2010 4839
Figure 2. Molecular structure of 8. Thermal ellipsoids are shown
at the 50% probability level. Isopropyl groups and H atoms are
˚
omitted for clarity reasons. Selected bond lengths (A) and angles
(deg): Sn1-O1 = 2.030(1), O1-C1 = 1.404(2), Sn1-N1 =
2.191(2), Sn1-N3 = 2.192(1); Sn1-O1-C1 = 120.19(11), N1-
Sn1-O1= 91.85(6), N1-Sn1-N3=83.61(6).
Figure 3. Molecular structure of 10. Thermal ellipsoids are
shown at the 50% probability level. Hydrogen atoms are
˚
omitted for clarity reasons. Selected bond lengths (A) and angles
(deg): Sn1-C6 = 2.3044(17), Sn1-N1 = 2.1861(12); N1-
Sn1-C6=93.38(5), N1-Sn1-N2 =86.05(5).
Scheme 4. Preparation of Compound 10
Scheme 3. Reaction of LSnH (1) with C6F6
cleavage occurs at the para position. Moreover, in the case of
4-fluorobenzophenone and pentafluorobenzaldehyde there
are no metathesis reactions. In the former case, the inductive
effect dominates compared with the mesomeric effect; there-
fore, only the addition reaction occurs. In the latter case,
the aldehyde group is more reactive in comparison with
the ketone group.
The pale yellow compound 10 was characterized by micro-
analysis, multinuclear NMR spectroscopy, and EI mass
spectrometry. Furthermore, it was characterized by single-
crystal X-ray structural analysis. Compound 10 crystallizes
in the monoclinic space group P21/n with one molecule in the
asymmetric unit (Figure 3). 10 is soluble in common organic
solvents such as benzene, THF, n-hexane, and n-pentane.
The NMR data are in complete agreement with those
obtained from the reaction of 1 with C6F6.
Finally, we selected C6F6 as a reactant and followed the
reaction with LSnH (1) (Scheme 3). The 1H NMR spectrum
from the crude product showed the formation of four pro-
ducts: one is the free ligand LH, another one is LSnF (2), and
the third one is C6F5H (9). We concluded that the last
compound is LSnC6F5 (10), because a similar reaction of
[1,3,4-(Me3C)3C5H2]2CeH with C6F6 leads to the intermedi-
ate [1,3,4-(Me3C)3C5H2]2CeC6F5, and it decomposes slowly
to [1,3,4-(Me3C)3C5H2]2CeF.4 In the 119Sn NMR spectrum
we observed only two resonances, one doublet for LSnF (1)
and another resonance for the compound LSnC6F5 (10) at
δ -176.42 ppm. In the 1H NMR spectrum the resonance for
the proton in C6F5H was observed at δ 5.95 ppm, which was
a triplet of triplets, due to the coupling with the neighboring
fluorine atoms.
Summary and Conclusion
In summary, we have shown the different types of reac-
tions of tin(II) hydride with carbonyl compounds containing
aromatic C-F bonds. The reaction of LSnH (1) with
PhCOC6F5 and C6F5COC6F5, resulted in the formation of
metathesis products by exchange of fluorine by hydrogen
and nucleophilic addition of Sn-H to the respective carbonyl
group. Moreover, compound 1 reacts with C6F6 at room
temperature, formingLSnF (2), C6F5H (9), LH, and LSnC6F5
(10). In conclusion, we have reported the cleavage of C-F
bonds using LSnH in the absence of additional catalyst. We
are currently investigating other main-group reagents for
C-F bond activation.
1
The H NMR data of 2 and 9 match well with those of
previously reported values.10,11 The formation of compound
10 was confirmed by its direct synthesis from LSnCl12 and
C6F5Li.13 The latter was prepared in situ from C6F5I and
n-BuLi (Scheme 4).
Experimental Section
General Considerations. All manipulations were performed
under a dry and oxygen-free atmosphere (N2) using standard
Schlenk techniques or inside a MBraun MB 150-GI glovebox
maintained at or below 1 ppm of O2 and H2O. Solvents were
purified with the M-Braun solvent drying system. The starting
(12) Ding, Y.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H.-G.;
Power, P. P. Organometallics 2001, 20, 1190–1194.
(13) Alberti, D.; Porschke, K.-R. Organometallics 2004, 23, 1459–
1460.
€

4840 Organometallics, Vol. 29, No. 21, 2010
Jana et al.
Table 1. Summary of Crystal Data and Refinement
Results for Compounds 8 and 10
material 1 and LSnCl were prepared using literature procedures.
8a,12 Other chemicals were purchased and used as received. 1H,
19F, and 119Sn NMR spectra were recorded on a Bruker Avance
DRX 500 MHz instrument and referenced to the deuterated
solvent in the case of the 1H NMR; CFCl3 and SnMe4 were used
as references for the 19F and 119Sn NMR spectra, respectively.
Elemental analyses were performed by the Analytisches Labor
8
10
empirical formula
CCDC no.
T (K)
C36H43F5N2OSn
745457
133(2)
C35H41F5N2Sn
759435
133(2)
€
€
€
des Instituts fur Anorganische Chemie der Universitat Gottingen.
Infrared spectral data were recorded on a Perkin-Elmer PE-1430
instrument. EI-MS were measured on a Finnigan Mat 8230 or a
Varian MAT CH5 instrument. Melting points were measured in
cryst syst
space group
triclinic
P1
monoclinic
P21/n
13.351(3)
18.698(4)
13.566(3)
90
102.84(3)
90
3301.8(11)
4
1.415
˚
a (A)
12.074(2)
12.398(3)
12.821(3)
82.25(3)
72.91(3)
71.68(3)
1739.6(7)
2
˚
b (A)
˚
c (A)
€
sealed glass tubes with a Buchi B 540 melting point instrument.
R (deg)
β (deg)
γ (deg)
Synthesis of LSnOCHPh(C6F5) (3; L= HC{(CMe)(2,6-iPr2-
C6H3N)}2) and PhCO(4-C6F4H) (5). In a NMR tube loaded with
PhCOC6F5 (0.136 g, 0.50 mmol) and LSnH (1; 0.270 g, 0.50
mmol) was added 1 mL of C6D6 at room temperature. After
24 h, the NMR spectrum was measured, showing the formation
of compounds 3 and 5 in a ratio of 0.6:1.0. Data for 3: 1H NMR
(200 MHz, C6D6) δ 6.85-7.65 (m, 6H, Ar-H), 6.41 (s, 1H, CH),
4.78 (s, 1H, γ-CH), 3.56 (sept, 2H, CH(CH3)2), 3.13 (sept, 2H,
CH(CH3)2), 1.53 (s, 6H, CH3), 1.44 (d, 6H, CH(CH3)2), 1.23
(d, 6H, CH(CH3)2), 1.11 (d, 6H, CH(CH3)2), 0.90 (d, 6H,
CH(CH3)2); 119Sn{1H} NMR (186.46 MHz) δ -217 ppm. Data
for 5: 1H NMR (200 MHz, C6D6) δ 6.18 (tt, 3J(F-H)=9.65 Hz,
4J(F-H) =7.30 Hz, 1H, 4-H) ppm.
Synthesis of LSnOCH(C6F5)2 (4; L=HC{(CMe)(2,6-iPr2C6-
H3N)}2) and C6F5CO(4- C6F4H) (6). A solution of C6F5COC6F5
in toluene (0.360 g, 1.00 mmol, 10 mL of toluene) was added by
cannula to a solution of LSnH (1) in toluene (0.54 g, 1.00 mmol
in 20 mL of toluene) at room temperature. After 24 h, all
volatiles were removed in vacuo, and the remaining residue
was extracted with n-hexane (25 mL). The 1H NMR spectrum
showed the formation of compounds 4 and 6 in a ratio of 0.8:1.0.
Data for 4: 1H NMR (500 MHz, C6D6) δ 6.99-7.13 (m, 15H,
Ar-H), 6.72 (s, 1H, CH), 4.77 (s, 1H, γ-CH), 3.46 (sept, 2H,
CH(CH3)2), 3.02 (sept, 2H, CH(CH3)2), 1.48 (s, 6H, CH3), 1.17
(d, 6H, CH(CH3)2), 1.14 (d, 6H, CH(CH3)2), 1.08 (d, 6H,
CH(CH3)2), 1.06 (d, 6H, CH(CH3)2); 119Sn{1H} NMR (186.46
MHz) δ -252 ppm; EI-MS (70 eV) m/z (%) 900 (100) [Mþ].
Data for 6: 1H NMR (500 MHz, C6D6) δ 6.08 (tt, 3J(F-H) =
9.56 Hz, 4J(F-H)= 7.45 Hz, 1H, 4-H) ppm.
3
˚
V (A )
Z
Dcalcd (g cm-3
)
1.400
0.791
μ (mm-1
)
0.828
2H, CH2), 3.57 (sept, 2H, CH(CH3)2), 3.13 (sept, 2H, CH(CH3)2),
1.58 (s, 6H, CH3), 1.31 (d, 6H, CH(CH3)2), 1.24 (d, 6H, CH-
(CH3)2), 1.20 (d, 6H, CH(CH3)2), 1.09 (d, 6H, CH(CH3)2). 19
F
NMR (188.29 MHz, C6D6): δ -143.9 (dd, 2F, o-F), -158.95 (t,
F, p-F), -163.95 (td, 2F, m-F). 119Sn{1H} NMR (186.46 MHz):
δ -262 ppm. EI-MS (70 eV): m/z (%) 537 (100) [Mþ - OCH2-
C6F5]. Anal. Calcd for C36H43F5N2OSn (734.23): C, 58.95; H,
5.91; N, 3.82. Found: C, 58.24; H, 5.90; N, 3.72.
Reaction of C6F6 and LSnH (1) with the Formation of LSnF
(2), C6F5H (9), LSnC6F5 (10), and LH. In a NMR tube C6F6
(0.095 g 0.50 mmol) and LSnH (1; 0.270 g, 0.50 mmol) were
loaded, and 1 mL of C6D6 was added at room temperature.
After 24 h the 1H NMR spectrum was recorded and showed the
formation of compounds 2, 9, LH, and 10. Data for 2: yield 0.13
g (50%), with respect to LSnH; 119Sn{1H} NMR (186.46 MHz)
δ -371.5 ppm. Data for 9: yield 0.04 g (46%), with respect to
LSnH; 1H NMR (200 MHz, C6D6) δ 5.95 (m, 1H, Ar-H) ppm;
19F NMR (188.29 MHz, C6D6) δ -139.4 (m, 2F, o-F),
-154.0 (t, 1F, p-F), -162.7 (m, 2F, m-F). Data for 10: yield
0.056 g (17%), with respect to LSnH; 119Sn{1H} NMR (186.46
MHz) δ -176.42 ppm. Data for LH: yield 0.071 g (34%), with
1
respect to LSnH; H NMR (200 MHz, C6D6) δ 12.45 (s, 1H,
N-H) ppm.
Synthesis of LSnOCHPh(4-C6H4F) (7; L = HC{(CMe)(2,6-
iPr2C6H3N)}2). A solution of PhCO(4-C6H4F) (0.200 g, 1.00
mmol; 10 mL of toluene) was added by cannula to a solution of
LSnH (1) in toluene (0.54 g, 1.00 mmol in 20 mL of toluene) at
room temperature. After 24 h, all volatiles were removed in
vacuo, and the remaining residue was extracted with n-hexane
(25 mL). Compound 7 was obtained after evaporation of the
solvent. Yield: 0.605 g (82%). Mp: 130 °C. 1H NMR (300 MHz,
C6D6): δ 6.65-7.63 (m, 15H, Ar-H), 5.88 (s, 1H, CH), 4.75 (s,
1H, γ-CH), 3.63 (sept, 2H, CH(CH3)2), 3.11 (sept, 2H, CH-
(CH3)2), 1.55 (s, 6H, CH3), 1.20 (d, 3H, CH(CH3)2), 1.18 (d, 3H,
CH(CH3)2), 1.13 (d, 3H, CH(CH3)2), 1.12 (d, 3H, CH(CH3)2),
1.11 (d, 3H, CH(CH3)2), 1.10 (d, 3H, CH(CH3)2), 1.08 (d,
3H, CH(CH3)2), 1.07 (d, 3H, CH(CH3)2). 19F NMR (188.29
MHz, C6D6): δ -112.3 (m, 1F, p-F). 119Sn{1H} NMR (186.46
MHz): δ -212 ppm. EI-MS (70 eV): m/z (%) 737 (90) [M]þ,
652 (100) [Mþ - C6H4F]. Anal. Calcd for C42H51FN2OSn
(738.30): C, 68.39; H, 6.97; N, 3.80. Found: C, 68.75; H, 7.16;
N, 3.62.
Synthesis of LSnOCH2C6F5 (8; L = HC{(CMe)(2,6-iPr2C6-
H3N)}2). A solution of C6F5CHO in toluene (0.196 g, 1.00 mmol
in 5 mL of toluene) was added by cannula to a solution of LSnH
(1) in toluene (0.54 g, 1.00 mmol in 20 mL of toluene) at room
temperature. After 24 h all volatiles were removed in vacuo, the
remaining residue was extracted with n-hexane (25 mL), and the
extract was concentrated to about 15 mL and stored in a -30 °C
freezer. After 4 days yellow crystals of 8 were formed. Yield:
0.600 g (82%). Mp: 138 °C. 1H NMR (300 MHz, C6D6): δ 6.95-
7.13 (m, 6H, Ar-H), 4.80 (s, 1H, γ-CH),4.67(t,4J(F-H)=4.18 Hz,
Synthesis of LSnC6F5 (10; L = HC{(CMe)(2,6-iPr2C6H3N)}2).
To a stirred solution of C6F5I (0.795 g, 2.70 mmol) in diethyl
ether (30 mL) was added dropwise 1.70 mL of nBuLi (1.6 M, in
n-hexane, 2.70 mmol) at -78 °C. The reaction mixture was
stirred for an additional 1 h at this temperature. This mixture
was transferred directly to the solution of LSnCl (1.54 g, 2.70
mmol) in diethyl ether (30 mL) at -78 °C. The resulting reaction
mixture was then warmed to room temperature. After 6 h all
volatiles were removed in vacuo, and the remaining residue was
extracted with n-hexane (35 mL) and the extract was concen-
trated to about 15 mL and stored in a -30 °C freezer. After
2 days, pale yellow block-shaped crystals of 10 were formed.
Yield: 1.15 g (60%). Mp: 173 °C. 1H NMR (300 MHz, C6D6):
δ 6.89-7.15 (m, 6H, Ar-H), 5.08 (s, 1H, γ-CH), 3.22 (sept, 2H,
CH(CH3)2), 2.89 (sept, 2H, CH(CH3)2), 1.55 (s, 6H, CH3), 1.27
(d, 6H, CH(CH3)2), 1.11 (d, 6H, CH(CH3)2), 0.96 (d, 6H,
CH(CH3)2), 0.52 (d, 6H, CH(CH3)2). 19F NMR (188.29 MHz,
C6D6): δ -117 (br, 2F, o-F), -155.0 (t, 1F, p-F), -161 (m, 2F,
m-F). 119Sn{1H} NMR (186.46 MHz): δ -176.42 ppm. EI-MS
(70 eV): m/z (%) 704 (100) [M]þ. Anal. Calcd for C35H41F5N2Sn
(704.22): C, 59.76; H, 5.87; N, 3.98. Found: C, 59.73; H, 6.11;
N, 3.97.
Crystallographic Details for Compounds 8 and 10. Suitable
crystals of 8 and 10 were mounted on a glass fiber, and data
were collected on an IPDS II Stoe image-plate diffractometer
˚
(graphite-monochromated Mo KR radiation, λ=0.710 73 A) at
133(2) K. The data were integrated with X-area. The structures
were solved by direct methods (SHELXS-97)14 and refined by

Article
Organometallics, Vol. 29, No. 21, 2010 4841
full-matrix least-squares methods against F2 (SHELXL-97).14
All non-hydrogen atoms were refined with anisotropic displace-
ment parameters. The hydrogen atoms were refined isotropi-
cally on calculated positions using a riding model. Crystal data
and refinement results for 8 and 10 are given in Table 1.
Acknowledgment. This work was supported by the
Deutsche Forschungsgemeinschaft.
Supporting Information Available: CIF files giving X-ray data
for 8 and 10 and figures giving 119Sn NMR spectra. This
material is available free of charge via the Internet at http://
pubs.acs.org.
(14) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112–122.