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C.A. Stewart et al. / Polyhedron 32 (2012) 14–23
2
–CF3), 129.6 (q, JC–F = 31 Hz, m-C6H3), 136.1 (s, p-py), 149.6 (s, o-
py), 154.9 (s, ipso-C6H3), 159.8 (s, –CO2) ppm. IR spectrum (Nujol
1H, p-C6H3). 119Sn{1H} NMR (C6D6, relative to Me4Sn): d ꢁ560. IR
spectrum (Nujol mull, cmꢁ1): 2879 (br), 1577 (m), 1162 (s), (w),
907 (s), 829 (s), 709 (br).
mull, cmꢁ1
) m 1614 (s), 1595 (s), 1444 (m), 1340 (s), 1274 (s),
1247 (m), 1173 (s), 11332 (s), 1078 (m), 1019 (m), 844 (s).
2.9. Reactions of 3 with OCS to yield multiple products
2.5. Preparation of Sn[N(SiMe3)(ArF)]2 (3)
Two procedures (stoichiometric addition and excess OCS addi-
tion) were used in the reaction of 3 with OCS; however, both led
to a variety of products. Into a Fisher-Porter bottle reactor system
was added 3–4 mmoles of 3 in anhydrous hexane at 25 °C. The
reactor was pressurized using either an exact 2:1 molar ratio of
OCS:3 or excess OCS, and then stirred for 30 min. All reactions were
notably exothermic, and the color of the solution changed to deep
brown over the 30 min reaction period. The solution was cooled to
ꢁ78 °C for 1 h and purged of the volatile products using a Schlenk
line under reduced pressure. After gradual warming to room tem-
perature, the solvents were removed and the products analyzed by
NMR spectroscopy. No isolated or individual products could be
obtained.
A solution of 1 (2.00 g, 3.82 mmol) in 20 ml anhydrous diethyl
ether cooled to 0 °C was transferred via cannula to suspension of
SnCl2 (0.36 g, 1.91 mmol) in 20 ml anhydrous diethyl ether held
at 0 °C. The mixture was allowed to warm to room temperature
over 2 h, then filtered to remove LiCl. The solvent was removed un-
der vacuum to give a viscous dark yellow to brown oil 3 (1.50 g,
84%). 1H NMR (DMSO-d6, 300 MHz): d 0.12 (s, 9H, –CH3), 6.75 (s,
1H, p-C6H3), 6.92 (s, 2H, o-C6H3) ppm. 13C{1H} NMR (DMSO-d6,
75 MHz): d 2.7 (–CH3), 109.0 (s, p-C6H3), 123.8 (s, o-C6H3), 123.9
(q, JC–F = 272 Hz, –CF3), 128.6 (q, JC–F = 32 Hz, m-C6H3), 156.4 (s,
ipso-C6H3) ppm. 119Sn{1H} (DMSO-d6, 112 MHz): d ꢁ12 ppm. Anal.
Calc. for C22H24F12N2Si2Sn: C, 36.74; H, 3.36; N, 3.89. Found C,
37.22; H, 3.57; N, 3.20%.
1
2
2.10. Thermal treatment and distillation of crude 3 to produce 6
2.6. Preparation of [(ArFN)2C(OSiMe3)]2Sn 4 from CO2
Essentially the same procedure used above in Section 2.4 was
followed to obtain crude 3. 3,5-(CF3)2C6H3(Me3Si)NH (5.00 g,
16.6 mmol) dissolved in 125 mL diethyl ether was cooled to 0 °C
in an ice bath and 2.5 M n-BuLi (6.6 mL, 16.6 mmol) was added
dropwise. Upon completion of addition the ice-bath was removed
and the slightly yellow reaction mixture allowed to stir at room
temperature for 1 h. In a separate flask a solution of SnCl2
(1.57 g, 8.3 mmol, finely ground) in 100 mL of diethyl ether was
prepared and cooled to 0 °C in an ice bath. The 3,5-(CF3)2C6H3(Me3-
Si)NLi/ether solution was added dropwise. The reaction mixture
was allowed to slowly warm to room temperature and stirred
overnight. The reaction mixture was filtered through a medium
porosity glass frit. The solids (LiCl) were washed three times with
75 mL aliquots of diethyl ether. The volume of the filtrate was re-
duced under vacuum to give a dark yellow oil. A AgNO3 test was
performed on the oil, which indicated the presence of Clꢁ (LiCl).
The dark yellow oil was distilled on a short path column under vac-
Compound 3 (1.50 g, 2.09 mmol) was dissolved in toluene
(30 mL). CO2 was bubbled through this solution at room tempera-
ture for 30 min. The resulting reaction mixture was concentrated
by removing about half the volume of toluene under vacuum.
The mixture was allowed to sit at 25 °C until yellow crystals of 4
precipitated (1.25 g, 1.01 mmoles) in 48% yield based on Sn,
assuming as in previous studies that the other Sn-containing prod-
uct is Sn(OSiMe3)2 [3], m.p. 154–156 °C. X-ray quality crystals of 4
were grown from toluene at ꢁ25 °C over several days. 1H NMR
(DMSO-d6, 300 MHz): d 0.01 (s, 9H, –CH3), 7.26 (s, 2H, p-C6H3),
8.13 (s, 4H, o-C6H3) ppm. 13C{1H} NMR (DMSO-d6, 75 MHz): d 1.7
1
(s, –CH3), 111.9 (s, p-C6H3), 118.9 (s, o-C3H6), 123.4 (q, JC–F
=
2
273 Hz, –CF3), 130.8 (q, JC–F = 32 Hz, m-C3H6, 146.8 (s, ipso-C6H3),
161.0 (s, –C(OSiMe3) ppm. 119Sn{1H} NMR (DMSO-d6, 112 MHz): d
ꢁ557 ppm. IR spectrum (Nujol mull, cmꢁ1): 2924 (br), 1610 (w),
1518 (s), 1493 (s) 1372 (s), 1281 (s), 1171 (s), 1132 (s), 1118 (m),
848 (s), 815 (s), 699 (s).
uum (10 lm Hg). A clear bright yellow oil was collected between
80 and 120 °C. The oil solidified upon cooling to give a bright yel-
low, slightly waxy crystalline solid, m.p. 60–68 °C (3.16 g, 53%
yield). Crystals suitable for X-ray diffraction analysis can be grown
by dissolving the waxy crystals in toluene at ꢁ25 °C over night. 1H
NMR (C6D6, 300 MHz): d 0.46 (s, 9H, –CH3), 7.15 (s, 1H, p-C6H3),
2.7. Preparation of [(ArFN)2C(OSiMe3)]2Sn 4 from ArFN@C@O
(3,5-(CF3)2C6H3)N@C@O (1.45 g, 5.68 mmol) was dissolved in
20 ml anhydrous toluene and added dropwise to a solution of 3
(2.05 g, 2.85 mmol) in 50 ml anhydrous toluene. During the addi-
tion a white precipitate was formed. The reaction mixture was stir-
red for 1 h at room temperature. The sample was then heated to
35 °C in order to dissolve the precipitate. The solution was cooled
to ꢁ25 °C, which yielded yellow crystals (2.50 g, 71%), m.p. 155–
157 °C. NMR and single crystal X-ray analysis of the isolated crys-
talline product indicated the product was identical to a sample of 4
prepared from CO2 and 3. An IR spectrum of the supernatant indi-
cates the presence of additional product 4.
7.69 (s, 1H, o-C6H3) ppm. 119Sn NMR (CDCl3, 112 MHz):
ꢁ164 ppm.
d
2.11. X-ray crystallography
Crystallographic data were collected on a Bruker X8 APEX2
CCD-based X-ray diffractometer using monochromated Mo K
a
radiation (k = 0.71073 Å). As all of the compounds are air-sensitive
the crystals were always handled under inert atmosphere. The
single crystals were coated in oil (Paratone-N™) and mounted on
nylon cryoloops (Hampton Research). Bruker APEX2 software
was used to collect and process the data [14]. Absorption correc-
tions were applied for all data by SADABS [15]. The structures were
solved by either the direct methods and were refined by full matrix
least-squares method on F2 with SHELXTL [16]. All non-hydrogens
were refined anisotropically with some CF3 groups modeled as
disordered, and hydrogen atoms were fixed at calculated geomet-
ric positions. PLATON/SQUEEZE was used to treat disordered
solvent molecules [17] in 2 and 4. Crystallographic and refinement
data for 1, 2, 4, 5, and 6 are given in Table 1. All crystallographic
figures were prepared using DIAMOND 3.2 g software [18].
2.8. Preparation of {[(ArF)(Me3Si)N]CS2}2Sn 5 via insertion of CS2 into
3
Neat excess CS2 (0.82 g, 10.77 mmol) was added to a dark
brown solution of 3 (3.45 g, 4.80 mmol) in 50 ml anhydrous hex-
anes. Upon addition of the CS2 the reaction mixture changed color
to a light brown. The reaction mixture was stirred for 2 h at room
temperature. About half of the solvent was removed under vacuum
and the reaction mixture cooled to ꢁ22 °C overnight. Complex 5
was isolated as brown crystals (2.79 g, 67%), m.p. 98–100 °C. 1H
NMR (C6D6): d 0.01 (s, 9H, -SiMe3), 7.29 (s, 2H, o-C6H3), 7.61 (s,