Organometallics
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135.70, 134.58 (q, J = 364 Hz), 132.41, 127.99, 127.04, 126.99,
125.94, 124.96, 124.70, 124.14, 63.11, 34.97, 30.98, 20.97. 19F NMR
(CDCl3): δ −20.29 (s). HRMS electrospray (m/z): [M − F]+ calcd
for C29H30F2N3O2PdS, 628.1056; found, 628.1058.
J = 8.6 Hz, 2H), 6.26 (d, J = 5.4 Hz, 1H), 2.28 (s, 3H), 1.22 (s, 9H).
13C{1H} NMR (CDCl3): δ 157.94, 157.10, 155.10, 150.88 (m),
149.27, 148.23, 140.07, 139.52, 136.07, 131.58, 131.53, 129.08, 127.09,
125.28, 124.18, 124.02, 121.64, 121.08, 114.69 (q, J = 378 Hz), 74.26,
34.86, 31.07, 20.51. 19F NMR (CDCl3): δ −20.44 (d, J = 4.8 Hz),
−285.11 (br m). HRMS electrospray (m/z): [M + H]+ calcd for
C29H30F4N3O2PdS, 666.1024; found, 666.1021.
(dpaa)PdIV(4-MeC6H4)(CF3)(Cl) (10). Iodobenzene dichloride
(77 mg; 0.28 mmol) was added to a solution of (dpaa)PdII(4-
MeC6H4)(CF3) (8; 110 mg, 0.22 mmol) in acetonitrile (5 mL) at
room temperature. The reaction mixture was stirred at room
temperature for 20 min, and then solvent was removed under reduced
pressure. The residue was purified on a silica gel column that was
eluted first with ethyl acetate, then with THF, and finally with 10%
methanol in THF. Fractions that contained pure product (TLC
control) were evaporated under reduced pressure, and the resulting
residue was dissolved in diethyl ether (20 mL). This solution was
filtered through a cotton plug, and the volume of the solution was
reduced to 10 mL. The product was then precipitated with hexanes
(30 mL), collected by filtration, washed with hexanes, and dried under
(dpaa)PdIV(4-MeC6H4)(CF3)(F) (13a,b). (dpaa)PdII(4-MeC6H4)-
(CF3) (8; 58 mg, 0.12 mmol) was dissolved in CH2Cl2 (4 mL), and
NFTPT (38 mg, 0.13 mmol) was added at room temperature. The
reaction mixture was stirred at room temperature for 20 min. The
CH2Cl2 solution was then washed with water (4 × 5 mL), dried over
anhydrous Na2SO4, filtered, and evaporated under reduced pressure.
1H NMR and 19F NMR analysis of the crude residue showed the
presence of two Pd(IV) complexes in an approximately 2:1 ratio.
These compounds were separated by preparative TLC (mobile phase
10% methanol in THF) to yield the major isomer 13a (24 mg, 40%)
and minor isomer 13b (20 mg, 33%) as yellow powders. When
oxidation was conducted in acetonitrile, only isomer 13a was formed
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reduced pressure. Yield: 55 mg (47%) of an orange powder. H NMR
(CDCl3): δ 9.03 (d, J = 5.0 Hz, 1H), 8.49 (d, J = 5.3 Hz, 1H), 7.87
(multiple peaks, 2H), 7.73 (multiple peaks, 2H), 7.43 (t, J = 6.0 Hz,
1H), 7.25 (multiple peaks, 2H), 6.95 (broad d, J = 8.1 Hz, 2H), 6.79
(d, J = 8.1 Hz, 2H), 2.25 (s, 3H), 1.69 (s, 3H). 13C{1H} NMR
(CDCl3): δ 175.06, 158.16, 158.10, 149.75, 149.49, 148.94 (q, J = 2.9
Hz), 140.43, 140.17, 135.76, 135.55, 129.15, 124.40, 124.19, 121.66,
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(53% isolated yield). Analytical data for 13a are as follows. H NMR
(CDCl3): δ 9.01 (d, J = 5.4 Hz, 1H), 8.25 (d, J = 5.4 Hz, 1H), 7.91
(multiple peaks, 2H), 7.74 (multiple peaks, 2H), 7.48 (t, J = 5.4 Hz,
1H), 7.27 (t, J = 6.1 Hz, 1H), 7.14 (d, J = 5.4 Hz, 1H; coupled with F),
7.09 (multiple peaks, 2H), 6.90 (d, J = 7.8 Hz, 2H), 2.32 (s, 3H), 1.82
(s, 3H). 13C{1H} NMR (CDCl3): δ 175.19 (d, J = 3.1 Hz), 157.69,
157.56, 152.01 (m), 149.22, 149.00, 140.46, 140.21, 136.01, 132.34 (d,
J = 6.6 Hz), 129.05, 124.33, 124.25, 121.80, 121.33, 116.84 (q, J = 376
Hz), 71.03, 24.75 (m), 20.51. 19F NMR (CDCl3): δ −290.85 (m),
−23.84 (d, J = 3.8 Hz). HRMS electrospray (m/z): [M + H]+ calcd
for C21H20F4N3OPd, 512.0572; found, 512.0574. Analytical data for
13b are as follows. 1H NMR (CDCl3): δ 8.98 (d, J = 5.1 Hz, 1H), 8.55
(d, J = 5.5 Hz, 1H), 8.03 (t, J = 7.7 Hz, 1H), 7.89 (t, J = 7.7 Hz, 1H),
7.85 (d, J = 8.0 Hz, 1H), 7.80 (d, J = 7.7 Hz, 1H), 7.26 (multiple
peaks, 2H), 7.07 (s, 1H), 6.90 (d, J = 8.0 Hz, 2H), 6.81 (multiple
peaks, 2H), 2.32 (s, 3H) and 1.43 (s, 3H). 13C{1H} NMR (CDCl3):
δ 175.94, 161.56, 158.30, 151.35 (m), 151.21 (m), 150.16, 141.64,
140.00, 136.46, 130.67 (d, J = 16.4 Hz), 129.50, 125.24, 124.37,
122.80, 122.21, 121.90 (q, J = 384 Hz) 69.97, 22.98 (d, J = 4 Hz),
20.49. 19F NMR (CDCl3): δ −312.97 (m), −33.80 (d, J = 3.2 Hz).
HRMS electrospray (m/z): [M + H]+ calcd for C21H19F4N3OPd,
512.0572; found, 512.0570.
121.32, 116.42 (q, J = 376 Hz), 71.72, 24.89 (q, J = 2.7 Hz), 20.40. 19
F
NMR (CDCl3): δ −13.08 (s). HRMS electrospray (m/z): [M + H]+
calcd for C21H20ClF3N3OPd, 528.0276; found, 528.0269. The
stereochemistry of this complex was assigned on the basis of the
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similarity of its H NMR spectrum to that of complex 12.
(dpsa)PdIV(4-MeC6H4)(CF3)(Cl) (11). Iodobenzene dichloride
(60 mg; 0.22 mmol) was added to a solution of (dpsa)PdII(4-
MeC6H4)(CF3) (9; 130 mg, 0.20 mmol) in MeCN (4 mL) at room
temperature. The reaction mixture was stirred at room temperature for
15 min, and then the volatiles were removed under reduced pressure.
The crude product was purified on a silica gel column (mobile phase:
hexane/EtOAc 1/1). Fractions containing pure product (TLC
control) were evaporated under reduced pressure. The resulting
residue was dissolved in dichloromethane (∼0.5 mL), and the product
was precipitated with the addition of hexane (20 mL). The precipitate
was collected by filtration, washed with diethyl ether, and dried under
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reduced pressure. Yield: 57 mg (42%) of a yellow powder. H NMR
(dpph)PdII(4-MeC6H4)(CF3) (15). (4-MePy)2Pd(4-MeC6H4)-
(CF3) (1; 300 mg, 0.66 mmol) was added to a solution of 1,1-
bis(2-pyridyl)phenylethane (dpph, 14; 182 mg, 0.70 mmol) in EtOAc
(15 mL) at room temperature. After the solution was stirred at room
temperature for 5 min, it was filtered through a pad of Celite. The
volume of the solution was reduced to 3 mL, and the product then
started to crystallize. This suspension was cooled at −20 °C for 2 h,
and then the precipitate was collected by filtration, washed with ethyl
acetate (3 × 1 mL), and dried under reduced pressure. Yield: 208 mg
(60%) of a white powder. The mother liquor was evaporated under
reduced pressure. The residue was suspended in diethyl ether,
collected by filtration, and dried under reduced pressure to yield
another 35 mg (10%) of the product. For complex 14 at room
temperature there is a hindered rotation about palladium−tolyl and
C−phenyl bonds on a NMR time scale. In order to resolve broad
resonances, 1H and 13C NMR spectra were measured at 50 and 46 °C.
1H NMR (CDCl3 at 50 °C): δ 9.09 (d, J = 4.9 Hz, 1H), 8.25 (d, J =
5.3 Hz, 1H), 7.87 (td, J = 7.8, 1.5 Hz, 1H), 7.77 (multiple peaks, 3H),
7.41 (t, J = 7.6 Hz, 2H), 7.36 (t, J = 7.4 Hz, 1H), 7.33 (t, J = 6.5 Hz,
1H), 7.03 (td, J = 7.2 Hz, 1.7 Hz, 1H), 6.97 (d, J = 7.0 Hz, 2H), 6.78
(d, J = 7.8 Hz, 2H), 6.73 (d, J = 7.6 Hz, 2H), 2.24 (s, 3H), 2.18 (s,
3H). 13C{1H} NMR (CDCl3 at 46 °C): δ 162.24, 160.53, 153.38,
152.78, 151.70 (q, J = 9.8 Hz), 148.27, 138.35, 138.10, 135.96, 134.61
(q, J = 366 Hz), 131.19, 128.87, 127.87, 127.12, 127.06, 123.04,
122.99, 122.78, 122.54, 57.52, 29.76, 20.91. 19F NMR (CDCl3 at
25 °C): δ −21.82 (s). HRMS electrospray (m/z): [M − F]+ calcd for
C26H23F2N3Pd, 507.0859; found, 507.0855.
(CDCl3): δ 9.01 (d, J = 5.2 Hz, 1H), 8.57 (d, J = 5.2 Hz, 1H), 7.83 (td,
J = 7.8, 1.0 Hz, 1H), 7.79 (td, J = 7.6, 1.0 Hz, 1H), 7.64 (d, J = 7.7 Hz,
1H), 7.55 (d, J = 8.4 Hz, 2H), 7.50 (d, J = 7.7 Hz, 1H), 7.38 (t, J = 6.5
Hz, 1H), 7.28 (t, J = 6.4 Hz, 1H), 7.24 (d, J = 8.4 Hz, 2H), 7.22 (d, J =
8.6 Hz, 2H), 6.82 (d, J = 8.6 Hz, 2H), 6.14 (s, 1H), 2.26 (s, 3H), 1.24
(s, 9H). 13C{1H} NMR (CDCl3): δ 158.69, 157.62, 154.63, 149.79,
149.76, 146.96, 140.67, 140.30. 139.66, 135.70, 135.52, 129.11, 126.60,
125.22, 124.48, 124.14, 120.66, 120.59, 115.03 (q, J = 378 Hz), 74.80,
34.83, 31.08, 20.42. 19F NMR (CDCl3): δ −11.90 (s). HRMS
electrospray (m/z): [M + Na]+ calcd for C29H29ClF3N3NaO2PdS,
704.0548; found, 704.0548.
(dpsa)PdIV(4-MeC6H4)(CF3)(F) (12). NFTPT (64 mg, 0.22
mmol) was added to a solution of complex 9 (130 mg, 0.20 mmol)
in MeCN (3 mL) at room temperature. The reaction mixture was
stirred at room temperature for 15 min. The volatiles were removed
under reduced pressure. The resulting residue was dissolved in CH2Cl2
(15 mL), and this solution was washed with water (4 × 15 mL), dried
over anhydrous Na2SO4, and evaporated under reduced pressure. The
crude product was purified on a silica gel column that was eluted first
with ethyl acetate and then with THF. Fractions containing pure
product (TLC control) were evaporated under reduced pressure. The
resulting residue was dissolved in dichloromethane (0.5 mL), and the
product was precipitated with the addition of hexane (20 mL). This
precipitate was collected by filtration, washed with diethyl ether, and
dried under reduced pressure. Yield: 91 mg (68%) of a yellow powder.
1H NMR (CDCl3): δ 8.82 (d, J = 5.1 Hz, 1H), 8.30 (d, J = 5.2 Hz,
1H), 7.70 (d, J = 8.8 Hz, 2H), 7.67 (td, J = 6.7, 1.5 Hz, 1H), 7.60
(multiple peaks, 3H), 7.50 (td, J = 7.7, 1.3 Hz, 1H), 7.28 (t, J = 6.8 Hz,
1H), 7.24 (d, J = 8.8 Hz, 2H), 7.12 (t, J = 6.4 Hz, 1H), 6.90 (d,
(dpph)PdIV(4-MeC6H4)(CF3)(Cl) (18). NFTPT (230 mg; 0.80
mmol) was added to a solution of (dpph)PdII(4-MeC6H4)(CF3) (15;
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dx.doi.org/10.1021/om200779j|Organometallics 2011, 30, 6617−6627