Organometallics
Article
was extracted with dichloromethane, filtered over a short plug of silica,
and precipitated by addition of hexane to give a yellow microcrystalline
powder, which was collected by filtration and washed with hexane. Yield:
69.2 mg, 66% (4a); 89.6 mg, 70% (4b); 72.5 mg, 59% (4c).
b = 12.9390(3) Å, c = 18.6140(4) Å, α = 107.1280(15)°, β = 101.8740(14)°,
γ = 95.8470(15)°, V = 2641.81(11) Å3, Z = 2, crystal dimensions 0.20 ×
0.22 × 0.25 mm3; Mo Kα radiation, 273(2) K; 20 841 reflections, 12 047
independent (μ= 1.130 mm−1); refinement (on F2) with SHELXTL
(version 6.1), 667 parameters, 0 restraints, R1= 0.0581 (I > 2σ) and wR2
(all data) = 0.1722, GOF = 1.028, max/min residual electron density
1.379/−1.196 e Å−3.
Computational Details. All models were fully optimized with the
Gaussian09 program package22 at the DFT level of theory. The hybrid
density functional B3PW9123,24 was utilized together with the basis set
consisting of the Stuttgart−Dresden effective core potential basis set
with an additional p-polarization function for Pd atoms (SDD(p)) and
the standard all-electron basis set 6-31G(d) for all other atoms.
Frequency calculations with no scaling were performed to ensure
optimization to true minima. None of the optimized structures gave
imaginary frequencies.
To further study the electronic properties of the complexes, we
performed topological charge density analysis with the QTAIM
(Quantum Theory of Atoms in Molecules)25 methods, which allowed
us to access the nature of the bonding via calculating different properties
of the electron density at the bond critical points. The analysis was done
with the AIMALL program26 using the wave functions obtained from
the DFT calculations with the computationally optimized structures.
This method has been previously used successfully in describing the
nature of the metal−metal bonding in, for example, linear chain
ruthenium complexes.27
Characterization data for 4a: 1H NMR (CDCl3, 500 MHz) δ 7.6 (m,
4H, ar), 7.3 (m, 8H, ar), 7.2 (m,4H, ar), 7.1 (m, 2H, ar), 7.0 (m, 4H, ar),
6.8 (m, 6H, ar), 4.9 (s, 2H, CH), 1.6 (s, 6H, CH3), 1.3 (s, 6H, CH3); 31
P
NMR (CDCl3, 202 MHz) δ 26.4 (s); 13C NMR (CDCl3, 125 MHz) δ
186, 185.3 (s, CO), 163.7 (m, C metalated), 139.5−122.5 (ar), 99.3
(s, C−H), 27.3 (s, CH3), 26.7 (s, CH3). Anal. Calcd for C46H42O4P2Pd2:
C, 59.18; H, 4.53. Found: C, 59.80; H, 4.56.
X-ray crystal structure data for 4a: Empirical formula, C46H42O4P2Pd2·
C6H14; crystal system, monoclinic; space group C2/c, a = 16.8200(6) Å,
b = 26.0490(7) Å, c = 10.7660(4) Å, β = 91.002(2)°, V = 4716.3(3) Å3,
Z = 4 crystal dimensions 0.22 × 0.22 × 0.26 mm3; Mo Kα radiation,
273(2) K; 9341 reflections, 5367 independent (μ = 4716.3(3) mm−1);
refinement (on F2) with SHELXTL (version 6.1), 275 parameters, 0
restraints, R1= 0.0445 (I > 2σ) and wR2 (all data) = 0.1359, GOF =
1.038, max/min residual electron density 0.737/−0.501 e Å−3.
Characterization data for 4b: 1H NMR (CDCl3, 500 MHz) δ 7.4 (m,
4H, ar), 7.4 (m, 4H, ar), 7.3 (m, 4H, ar), 7.2 (m, 4H, ar), 7.1 (m, 2H, ar),
7.0 (m, 4H, ar), 6.9 (m, 4H, ar), 6.8 (s, 2H, ar), 5.7 (s, 2H, CH); 19F
NMR (CDCl3, 282.4 MHz) δ −75.5 (m), −75.9 (m); 31P NMR
(CDCl3, 202 MHz) δ 26.9 (s); 13C NMR (CDCl3, 125 MHz) δ 174.4
(m, 2JC−F = 34 Hz, CO), 158.9 (m, C metalated), 138.4−123.7 (ar),
1
117.6 (q, JC−F = 286 Hz, CF3), 89.5 (s, C−H). Anal. Calcd for
Direct Catalytic Phenylation of 1-Methylindole. The procedure
reported by Sanford and co-workers has been followed.12 1-Methylindole
(65.6 mg, 0.5 mmol) and the precatalysts (0.0125 mmol, 2.5 mol % of
Pd) were dissolved in CH3CO2H (5 mL) (4b, 6b, 9a, 9b, 12 and 13 were
dissolved in a minimum volume of CH2Cl2), and the solution was stirred
at 298 K for 5 min. [Ph2I]PF6 (426.0 mg, 1 mmol) or [Ph2I]BF4 (367.9
mg, 1 mmol) was added, and the resulting solution stirred at 298 K
until no 1-methylindole was observed by 1H NMR. The reaction
mixture was filtered through a plug of siliceous earth and evaporated to
dryness. The resulting oil was dissolved in CH2Cl2 (25 mL) and
extracted with aqueous NaHCO3 (2 × 40 mL). The organic phase was
dried with Na2SO4, concentrated, and purified by chromatography on
silica gel using as eluent hexanes/ethylacetate (96:4). The reactions
were monitored by 31P and 1H NMR spectroscopy using a D2O coaxial.
C46H30F12O4P2Pd2: C, 48.06; H, 2.63. Found: C, 48.67; H, 2.83.
X-ray crystal structure data for 4b: Empirical formula, C46H30F12O4P2Pd2;
crystal system, triclinic; space group P1, a = 12.7000(2) Å, b =
̅
13.6670(2) Å, c = 13.7970(3) Å, α = 87.2950(12)°, β = 81.3370(11)°,
γ = 70.8280(12)°, V = 2263.13(7) Å3, Z = 2 crystal dimensions 0.20 ×
0.22 × 0.24 mm3; Mo Kα radiation, 273(2) K; 17 178 reflections, 10 220
independent (μ = mm−1); refinement (on F2) with SHELXTL (version
6.1), 595 parameters, 0 restraints, R1 = 0.0427 (I > 2σ) and wR2 (all data) =
0.1141, GOF = 1.064, max/min residual electron density 0.957/
−0.669 e Å−3.
Characterization data for 4c: 1H NMR (CDCl3, 500 MHz) δ 7.9 (m,
4H, ar), 7.8 (m, 4H, ar), 7.4−7.2 (m, 14H, ar), 6.7 (m, 2H, ar), 6.6 (m,
2H, ar), 6.4 (m, 2H, ar), 5.4 (s, 2H, CH), 1.1 (s, 18H, CH3), 0.8 (s, 18H,
CH3); 31P NMR (CDCl3, 202 MHz) δ 22.7 (s); 13C NMR (CDCl3, 125
MHz) δ 194.9, 194.5 (s, CO), 162.3 (m, C metalated), 136.2−122.1
(ar), 88.3 (s, C−H), 41.1 (s, C quaternary), 40.9 (s, C quaternary), 28.7
(s, CH3), 28.5 (s, CH3). Anal. Calcd for C58H66O4P2Pd2: C, 63.21; H,
6.04. Found: C, 63.15; H, 5.97.
Compound 11: 1H NMR (CDCl3, 400 MHz) δ 7.75 (d, 1H, 3JH−H
=
7.6 Hz), 7.63−7.60 (m, 2H), 7.56 (t, 2H, 3JH−H = 7.6 Hz), 7.51−7.45 (m,
2H), 7.36 (dt, 1H, 3JH−H = 8.0 Hz, 3JH−H = 1.2 Hz), 7.26 (m, 1H), 6.68
(s, 1H), 3.83 (s, 3H, CH3); 13C NMR (CDCl3, 100 MHz) δ 141.7 (s, C
quaternary), 138.5 (s, C quaternary), 132.9 (s, C quaternary), 129.5 (s, 2
C−H), 128.6 (s, 2 C−H), 128.1 (s, C quaternary), 127.9 (s, C−H),
121.8 (s, C−H), 120.6 (s, C−H), 120.0 (s, C−H), 109.7 (s C−H), 101.8
(s, C−H), 31.2 (s, CH3).
X-ray crystal structure data for 4c: Empirical formula, C58H66O4P2Pd2;
crystal system, triclinic; space group P1, a = 10.8140(3) Å, b =
̅
12.9040(3) Å, c = 19.6090(5) Å, α = 86.8720 (18)°, β = 89.1930(17)°,
γ = 77.1980(14)°, V = 2664.31(12) Å3, Z = 2, crystal dimensions 0.16 ×
0.18 × 0.23 mm3; Mo Kα radiation, 273(2) K; 18 462 reflections, 12 017
independent (μ = 0.779 mm−1); refinement (on F2) with SHELXTL
(version 6.1), 595 parameters, 0 restraints, R1= 0.0547 (I > 2σ) and wR2
(all data) = 0.1108, GOF = 1.084, max/min residual electron density
0.553/−0.715 e Å−3.
ASSOCIATED CONTENT
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S
* Supporting Information
Cyclic voltammogram, 31P NMR spectra of the reaction of 4c
with PhICl2 from 200 to 298 K, 31P NMR spectra of the 6b from
200 to 298 K, frontier molecular orbitals for 3b,c, 5a−c, 8a,b, and
9a,b, 31P NMR spectra of the progress of the catalytic reaction
with 4c, EDX spectra of the black solids obtained in the catalytic
reaction, 31P NMR spectra of the reaction of 4c and [Ph2I]PF6 in
acetic acid and the evolution of [Ph2I]PF6 in acetic acid, study by
UV−vis spectroscopy of the catalytic reaction with 3a, and
crystallographic data of compounds 3a,b, 4a−c, and 6b in CIF
format. This material is available free of charge via the Internet at
Preparation of Pd2[(C6H4)PPh2]2[CF3C(O)CHC(O)CF3]2Cl2 (6b).
To a solution at 223 K of 4b (50 mg, 0.044 mmol) in CH2Cl2 (5 mL)
was added iodobenzene dichloride (18 mg, 0.066 mmol). The solution
immediately changed from yellow to red. After 5 min of stirring, the
solution was evaporated to dryness and hexane was added. The red
microcrystalline precipitate obtained was isolated by filtration and
washed with hexane. Yield: 43.6 mg (82%).
Characterization data for 6b: 1H NMR (CD2Cl2, 400 MHz, 223 K) δ
8.1 (m, 4H, ar), 8.0 (m, 2H, ar), 7.6 (m, 4H, ar), 7.5 (m, 6H, ar), 7.3 (m,
2H, ar), 7.2 (m, 2H, ar), 7.1 (m, 2H, ar), 7.0 (m, 2H, ar), 6.9 (m, 2H, ar),
6.6 (s, 2H, ar), 5.7 (s, 2H, CH); 31P NMR (CD2Cl2, 162 MHz, 223 K) δ
4.6 (s); 13C NMR (CD2Cl2, 100 MHz, 223 K) δ 175.3 (q, 2JC−F = 34 Hz,
2
CO), 174.7 (q, JC−F = 34 Hz, CO), 154.9 (m, C metalated),
AUTHOR INFORMATION
■
1
1
141.9−121.3 (ar), 117.3 (q, JC−F = 287 Hz, CF3), 116.8 (dq, JC−F
=
287 Hz, 4JC‑p = 10 Hz, CF3), 90.4 (s, C).
Corresponding Author
*Tel: 00 34 963543147. Fax: 00 34 963543929. E-mail: angeles.
X-ray crystal structure data for 6b: Empirical formula, C48H34Cl6F12-
O P Pd ; crystal system, triclinic; space group P1, a = 11.9100(3) Å,
̅
4
2
2
J
dx.doi.org/10.1021/om300400k | Organometallics XXXX, XXX, XXX−XXX