Organometallics
Article
dried over and distilled over CaH2 prior to use. 1 was prepared as
described in the literature.8 AdNCO (Ad = admantyl), ArNCO (Ar =
2,6-Pri2C6H1 3), and [RhCl(cod)]2 were purchased from Sigma-Aldrich
Co. The H, 13C, 31P, and 119Sn NMR spectra were recorded on a
JEOL ECA 400 spectrometer. The chemical shifts δ are relative to
1
SiMe4 for H and 13C, to SnMe4 for 119Sn, and to H3PO4 for 31P.
Elemental analyses were performed by the Division of Chemistry and
Biological Chemistry, Nanyang Technological University. Melting
points were measured in sealed glass tubes and were not corrected.
[(PPh2NSiMe3)(PPh2S)C{C(O)N(Ad)}Sn:] (2). A solution of
AdNCO (0.041 g, 0.23 mmol) in THF (5 mL) was added dropwise to
1 (0.14 g, 0.11 mmol) in THF (5 mL) at 0 °C. The yellow suspension
was stirred at room temperature and turned clear gradually. After it
was stirred for 34 h, the reaction mixture was a pale yellow clear
solution. Volatiles were removed in vacuo, and the residue was
extracted with toluene. After filtration and concentration of the filtrate,
2 was obtained as colorless crystals. Yield: 0.068 g (38.8%). Mp 217
°C dec. Anal. Calcd for C39H44N2OP2SSiSn: C, 58.72; H, 5.56; N,
3.51. Found: C, 58.50; H, 5.47; N, 3.14. 1H NMR (399.5 MHz, 25 °C,
C6D6): δ −0.043 (s, 9H, SiMe3), 1.59−1.66 (m, 6H, Ad), 1.87−1.89
(d, 3H, Ad), 1.96−2.00 (m, 6H, Ad), 6.99−7.03 (m, 12H, Ph), 7.35−
7.40 (m, 2H, Ph), 8.15−8.18 (m, 4H, Ph), 8.80−8.86 (m, 2H, Ph).
13C{1H} NMR (100.5 MHz, 25 °C, C6D6): δ 2.37 (SiMe3), 30.57,
37.52, 43.51 (Ad), 56.70 (dd, JP−C = 56.6 Hz, JP′−C = 70.0 Hz, PCP),
127.11, 127.24, 128.22, 130.26, 130.28, 130.85, 130.88, 131.69, 131.72
(CH of Ph), 132.64 (dd, JP−C = 57.3 Hz, 3JP′−C = 10.5 Hz, Cipso of Ph),
134.46 (dd, JP−C = 57.3 Hz, 3JP′−C = 11.5 Hz, Cipso of Ph), 165.16 ppm
(CO). 31P{1H} NMR (161.7 MHz, 25 °C, C6D6): δ 22.29 (d, 2JP−P′
2
2
= 17.3 Hz, JSn−P = 86.7, 121.4 Hz), 41.23 ppm (d, JP−P′ = 13.0 Hz,
2JSn−P = 47.7, 73.7 Hz). 119Sn{1H} NMR (147.6 MHz, 25 °C, C6D6): δ
−255.15 ppm (br).
Figure 3. Molecular structure of 4 with thermal ellipsoids at the 50%
probability level. Disordered CH2Cl2 molecules are omitted for clarity.
Selected bond lengths (Å) and angles (deg): Sn(1)−C(1) =
2.3617(16), Sn(1)−Cl(1) = 2.5311(4), Sn(1)−N(1) = 2.2535(13),
P(2)−N(1) = 1.6060(14), P(1)−S(1) = 2.0256(6), C(1)−P(2) =
1.7370(15), C(1)−P(1) = 1.7233(15), Rh(1)−C(1) = 2.1715(16),
Rh(1)−S(1) = 2.4005(4); C(1)−Sn(1)−N(1) = 68.42(5), C(1)−
Sn(1)−Cl(1) = 96.79(4), N(1)−Sn(1)−Cl(1) = 100.17(4), Sn(1)−
N(1)−P(2) = 98.34(6), N(1)−P(2)−C(1) = 101.84(7), P(2)−C(1)−
Sn(1) = 90.79(6), Sn(1)−C(1)−Rh(1) = 76.66(5), C(1)−Rh(1)−
S(1) = 77.67(4), Rh(1)−S(1)−P(1) = 78.247(17), S(1)−P(1)−C(1)
= 99.71(6), P(1)−C(1)−Rh(1) = 91.53(7), P(1)−C(1)−P(2) =
134.23(10).
[(PPh2NSiMe3)(PPh2S)C¯{C(O)N(Ar)}Sn+:] (3). A solution of
ArNCO (0.05 mL, 0.23 mmol) in THF (5 mL) was added dropwise to
1 (0.14 g, 0.11 mmol) in THF (5 mL) at 0 °C. The yellow suspension
was stirred at room temperature and turned clear gradually. After it
was stirred for 15 h, the reaction mixture was a pale yellow clear
solution. Volatiles were removed in vacuo, and the residue was
extracted with toluene. After filtration and concentration of the filtrate,
3 was obtained as colorless crystals. Yield: 0.066 g (36.5%). Mp 185
°C dec. Anal. Calcd for C41H46N2OP2SSiSn: C, 59.78; H, 5.63; N,
3.40. Found: C, 59.53; H, 5.57; N, 3.32. 1H NMR (399.5 MHz, 22 °C,
3
C6D6): δ 0.21 (s, 9H, SiMe3), 0.51 (d, JH−H = 6.9 Hz, 3H,
CH(CH3)2), 0.67 (d, 3JH−H = 6.4 Hz, 3H, CH(CH3)2), 1.20 (d, 3JH−H
(GeCl)]7b (2.204(3) Å) and [(PPh2NSiMe3)2C{Rh(cod)}2]
(2.148(2), 2.168(2) Å).15d
In conclusion, the formation of [(PPh2NSiMe3)(PPh2
= 6.9 Hz, 3H, CH(CH3)2), 1.37 (d, 3JH−H = 6.8 Hz, 3H, CH(CH3)2),
3
3
2.26 (sept, JH−H = 6.8 Hz, 1H, CH(CH3)2), 3.03 (sept, JH−H = 6.9
Hz, 1H, CH(CH3)2), 6.40−6.45 (m, 2H, Ph), 6.51−6.57 (m, 4H, Ph),
6.83−6.87 (m, 1H, Ph), 7.03−7.16 (m, 4H, Ph), 7.23−7.27 (m, 1H,
Ph), 7.33−7.38 (m, 5H, Ph), 7.83 − 7.89 (m, 2H, Ph), 8.60−8.70 (m,
4H, Ph). 13C{1H} NMR (100.5 MHz, 25 °C, C6D6): δ 4.73 (SiMe3),
24.29, 24.70, 25.99, 26.64 (CH(CH3)2), 28.87, 29.13 (CH(CH3)2),
40.64 (dd, JP−C = 56.6 Hz, JP′−C = 74.3 Hz, PCP), 123.86, 124.18,
126.72, (Ar) 127.78, 127.91, 128.84, 128.87, 128.98, 129.00, 130.56,
130.59, 131.36, 131.39 (CH of Ph), 132.22 (dd, JP−C = 79.4 Hz, 3JP′−C
S)C{C(O)N(Ad)}Sn:] (2) and [(PPh2NSiMe3)(PPh2
S)C¯{C(O)N(Ar)}Sn+:] (3) illustrate that the reactions of 1
with isocyanates probably proceed via a [2 + 2] cycloaddition
of the >CSn: bond or an insertion reaction of the C−Sn+
bond with the NC bond of RNCO (R = Ad, Ar). Moreover,
the formation of [(PPh2NSiMe3)(PPh2S)C{Rh(cod)}-
(SnCl)] (4) underlines the nucleophilic character of the
Cmethanediide atom in 1. Furthermore, X-ray crystal structures
show that the C−Sn bonds in 2−4 are lengthened in
comparison with that in 1. These results are consistent with
the X-ray crystal structure and NBO analyses of 1, which show
that the Sn−Cmethanediide bond has some double-bond character
and the electron densities are mostly occupied by the
Cmethanediide atom. Thus, compound 1 could be between the
resonance forms [(PPh2NSiMe3)(PPh2S)CSn:]2 and
[(PPh2NSiMe3)(PPh2S)C−Sn:+]2.
3
= 11.5 Hz, Cipso of Ph), 134.20 (dd, JP−C = 75.8 Hz, JP′−C = 10.5 Hz,
Cipso of Ph), 140.56, 146.58, 146.77 (Ar), 166.82 ppm (CO).
31P{1H} NMR (161.7 MHz, 22 °C, C6D6): δ 27.79 (d, 2JP−P′ = 8.7 Hz,
2
2
2JSn−P = 69.4, 86.7 Hz), 37.44 ppm (d, JP−P′ = 8.7 Hz, JSn−P = 73.7,
134.4 Hz). 119Sn{1H} NMR (149.0 MHz, 22 °C, C6D6): δ −129.25
ppm (br).
[(PPh2NSiMe3)(PPh2S)C{Rh(cod)}(SnCl)] (4). A solution of
[RhCl(cod)]2 (0.079 g, 0.16 mmol) in THF (8.4 mL) was added
dropwise to a solution of 1 (0.20 g, 0.16 mmol) in THF (8.4 mL) at 0
°C. The yellow suspension was then stirred at room temperature and
turned clear and red gradually. After it was stirred for 5 h, the reaction
mixture became a red suspension with yellow solid. Volatiles were
removed in vacuo, and the residue was extracted with CH2Cl2. After
filtration and concentration of the filtrate, 4 was obtained as red
crystals. Yield: 0.18 g (55.4%). Mp 140 °C dec. Anal. Calcd for
C36H41ClNP2RhSSiSn: C, 49.87; H, 4.77; N, 1.62. Found: C, 49.63; H,
EXPERIMENTAL SECTION
All manipulations were carried out under an inert atmosphere of
nitrogen gas using standard Schlenk techniques. THF and toluene
were dried over and distilled over Na/K alloy prior to use. CH2Cl2 was
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dx.doi.org/10.1021/om300062n | Organometallics 2012, 31, 3888−3893