Organometallics
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(s, 24H, OCH2). 13C NMR (101 MHz, 300 K, CD2Cl2): δ 12.7 (s+d,
3JPt,C = 27 Hz, CH3), 15.6 (s+d, 2JPt,C = 20 Hz, CH2), 70.4 (s, OCH2),
CDCl3 (0.7 mL) was added at −80 °C. Then the NMR tube was
closed by melting and warmed to room temperature. 1H NMR
spectroscopic measurements revealed that in all cases the equilibrium
composition was reached within 10 min. The positions of the
equilibria were calculated from signals of nonsuperimposed protons;
see Supporting Information. The equilibrium constants given in Table
5 were obtained from at least two independent experiments using
different stoichiometric ratios (Table S3).
1
72.6 (s+d, JPt,C = 188 Hz, CCH2).
R/R′ = Me/t-Bu (5): Yield 120 mg, 90%. Anal. Calcd for
C19H36Cl3KO6Pt (701.02): C, 32.55; H, 5.18; Cl, 15.17. Found: C,
32.62; H, 5.56; Cl, 15.31. 1H NMR (200 MHz, 300 K, CDCl3): δ 1.42
3
(s, 9H, C(CH3)3), 2.15 (s+d, JPt,H = 32 Hz, 3H, CCH3), 3.63 (s,
24H, OCH2). 13C NMR (101 MHz, 300 K, CD2Cl2): δ 7.7 (s+d, 2JPt,C
2
X-ray Structure Determinations. Crystals suitable for X-ray
diffraction analyses were grown at room temperature from solutions
of complexes in CH2Cl2/acetone by slow addition of diethyl ether (5−
7) and diethyl ether/n-pentane (9), respectively. Intensity data were
collected on a STOE IPDS diffractometer at 200(2) K (9) and a
STOE STADI IV diffractometer at 293(1) K (5−7), with Mo Kα
radiation (λ = 0.71073 Å, graphite monochromator). Crystallographic
data and data collection parameters are given in Table S1. Absorption
corrections were applied using Ψ-scans for 5 (Tmin/Tmax 0.16/0.26), 6
(Tmin/Tmax 0.21/0.42), and 7 (Tmin/Tmax 0.21/0.42) and numerically
for 9 (Tmin/Tmax 0.28/0.88). The structures were solved by direct
methods with SHELXS-97 and refined using full-matrix least-squares
routines against F2 with SHELXL-97.25 Non-hydrogen atoms were
refined with anisotropic displacement parameters and hydrogen atoms
with isotropic displacement parameters. Hydrogen atoms were added
to their calculated positions and refined according to the riding model.
Computational Details. DFT calculations were carried out by the
Gaussian03 program package26 using the hybrid functional B3LYP.
The 6-311G(d,p)27 basis sets as implemented in Gaussian03 were
employed for C, H, O, and Cl atoms, while the relativistic
pseudopotential of the Ahlrichs group and related basis functions of
TZVPP quality28 were employed for Pt atoms. The appropriateness of
the functional in combination with the basis sets and effective core
potential used for reliable interpretation of structural and energetic
aspects of related platinum complexes has been demonstrated.29 All
systems were fully optimized without any symmetry restrictions. The
resulting geometries were characterized as equilibrium structures by
the analysis of the force constants of normal vibrations. Solvent effects
were considered according to the polarized continuum model.22 Basis
set superposition errors (BSSE) were calculated according to the
counterpoise method as implemented in Gaussian03.30 The atom
coordinates as well as energies of all calculated equilibrium structures
are given in the Supporting Information (S4). Energy decomposition
analyses were performed on the basis of the optimized structures of
the complexes and fragments, as given in the literature.21 The NBO
analyses were performed with the NBO module as implemented in
Gaussian03.31
= 27 Hz, CCH3), 29.1 (s+d, JPt,C = 17 Hz, C(CH3)3), 30.4 (s+d,
1
3JPt,C = 19 Hz, C(CH3)3), 68.1 (s+d, JPt,C = 176 Hz, CCH3), 70.0
1
(s, OCH2), 77.7 (s+d, JPt,C = 223 Hz, C(CH3)3).
R/R′ = Me/Ph (7): Yield 115 mg, 84%. Anal. Calcd for
C21H32Cl3KO6Pt (721.01): C, 34.98; H, 4.47; Cl, 14.75. Found: C,
34.80; H, 4.66; Cl, 15.01. 1H NMR (200 MHz, 300 K, CDCl3): δ 2.44
3
(s+d, JPt,H = 31 Hz, 3H, CH3), 3.63 (s, 24H, OCH2), 7.33−7.38 (m,
3H, p-H/m-H), 7.96−8.01 (m, 2H, o-H). 13C NMR (50 MHz, 300 K,
1
CD2Cl2): δ 8.8 (s+d, 2JPt,C = 27 Hz, CCH3), 68.2 (s+d, JPt,C = 172
1
Hz, CCH3), 70.4 (s, OCH2), 76.6 (s+d, JPt,C = 180 Hz, CPh),
123.4 (s+d, 2JPt,C = 28 Hz, CCCCH3), 128.6 (s+d, 2JPt,C = 20 Hz, m-
C), 131.4 (s, o-C), 131.7 (s, p-C).
Synthesis of [K(18C6)][PtCl3(t-BuCCt-Bu)] (6). To a solution of
2 (200 mg, 0.303 mmol) in CHCl3 (3 mL) was added 2,2,5,5-
tetramethylhex-3-yne (167 mg, 1.21 mmol), resulting in an intense
yellow-colored solution. After stirring the solution for 24 h at room
temperature the solvent and the volatile olefin were removed by
evaporating the solution to dryness in vacuo. Then the residue was
redissolved in CHCl3 (3 mL), a new batch of 2,2,5,5-tetramethylhex-3-
yne (167 mg, 1.21 mmol) was added, and the resulting solution was
treated as mentioned above. After eight repetitions of this procedure a
nearly complete degree of conversion (>96%) was observed by NMR
spectroscopy. Finally, the residue was washed with Et2O (2·1 mL) and
purified by dissolving in CH2Cl2/acetone and layering with Et2O.
Yield: 180 mg, 80%. Anal. Calcd for C22H42Cl3KO6Pt (743.10): C,
35.56; H, 5.70. Found: C, 35.58; H, 5.71. 1H NMR (200 MHz, 300 K,
CDCl3): δ 1.44 (s, 18H, C(CH3)3), 3.64 (s, 24H, OCH2). 13C NMR
2
(101 MHz, 300 K, CD2Cl2): δ 28.8 (s+d, JPt,C = 14 Hz, C(CH3)3),
1
30.7 (s+d, 3JPt,C = 20 Hz, C(CH3)3), 70.5 (s, OCH2), 78.8 (s+d, JPt,C
=
216 Hz, Ct-Bu).
Synthesis of [K(18C6)][PtCl3(MeCCCO2Me)] (8). At −30 °C to a
solution of 2 (190 mg, 0.287 mmol) in CHCl3 (3 mL) was added
methyl but-2-ynoate (1.41 g, 14.4 mmol), resulting in an intense
yellow-colored solution. After stirring the solution for 1 h at −30 °C
the solvent and the volatile olefin were removed by evaporating the
solution to the dryness in vacuo at this temperature and stirring for
another 3 h applying a vacuum (0.1 bar, −30 °C). Finally the product
was precipitated by layering with Et2O/n-pentane (3 mL) and washed
with n-pentane (2 × 3 mL). This product had to be recrystallized from
CHCl3 (2 mL) by layering with Et2O/n-pentane (3 mL) and washing
with n-pentane (2 × 3 mL). Yield: 121 mg, 60%. Anal. Calcd for
C17H30Cl3KO8Pt (702.95): C, 29.05; H, 4.30. Found: C, 28.90; H,
ASSOCIATED CONTENT
* Supporting Information
■
S
CIF files giving crystallographic data for 5−7, 9 (CCDC
838514−839517), crystallographic and structure refinement
data for 5−7, 9 (S1), description of crown ether conformations
in 5−7, 9 (S2), details of equilibrium constants of substitution
reactions (S3), as well as energies and atom coordinates of all
calculated equilibrium structures (S4). This material is available
1
3
4.46. H NMR (200 MHz, 300 K, CD2Cl2): δ 2.28 (s+d, JPt,H = 33
Hz, 3H, CCH3), 3.62 (s, 24H, OCH2), 3.83 (s, 3H, OCH3).
Synthesis of [K(18C6)][PtCl3(COC)] (9). To a solution of 2 (260 mg,
0.393 mmol) in CH2Cl2 (4 mL) was added cyclooctyne (63.8 mg,
0.590 mmol). After stirring the solution for 30 min at room
temperature the intense yellow-colored solution was filtered,
concentated in vacuo to 1 mL, and layered with n-pentane (2 mL).
The precipitate was filtered off, dried briefly in vacuo, and purified by
dissolving in CH2Cl2/acetone and layering with Et2O/n-pentane.
Yield: 269 mg, 96%. Anal. Calcd for C20H36Cl3KO6Pt (713.03): C,
33.69; H, 5.09. Found: C, 33.69; H, 5.08. 1H NMR (200 MHz, 300 K,
CD2Cl2): δ 1.65 (m, CCH2CH2CH2, 4H), 1.66 (m, CCH2CH2,
4H), 2.57 (m, CCH2CH2, 4H), 3.65 (s, OCH2, 24H). 13C NMR
(50 MHz, 300 K, CD2Cl2): δ 22.4 (s+d, 2JPt,C = 11 Hz, CCH2CH2),
AUTHOR INFORMATION
Corresponding Author
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REFERENCES
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13. (b) Zeise, W. C. Pogg. Ann. Phys. 1827, 9, 632.
3
28.9 (s, CCH2CH2CH2), 30.2 (s+d, JPt,C = 42 Hz, CCH2CH2,),
1
70.4 (s, OCH2), 76.6 (s+d, JPt,C = 236 Hz, CCH2). 195Pt NMR
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(107 MHz, 300 K, CD2Cl2): δ −2078.7 (s).
Reaction of [K(18C6)][PtCl3(MeHCCHMe)] (2) with Alkynes. In
a typical experiment complex 2 (15 mg, 0.023 mmol) was placed into
an NMR tube, and a solution of the requisite alkyne RCCR′ in
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dx.doi.org/10.1021/om200767q|Organometallics 2011, 30, 5919−5927