578 Organometallics, Vol. 25, No. 3, 2006
Sui-Seng et al.
gave the product as a brown-red precipitate (250 mg, 83%).
Recrystallization of a small portion of this solid from a C6H6/hexane
solution yielded crystals suitable for X-ray diffraction studies and
elemental analysis. 1H NMR (CDCl3, 400 MHz): δ 7.42-7.34 (m,
PPh3), 7.32 (d, 2JH-H ) 7.3 Hz, H7), 7.15 (t, 3JH-H ) 7.4 Hz, H6),
7.04 (d, JH-H ) 8.9 Hz, H1), 6.87 (t, JH-H ) 7.4 Hz, H5), 6.77
(br, H2), 6.29 (d, 3JH-H ) 7.4 Hz, H4), 4.68 (s, H3). 13C{1H} NMR
(CDCl3, 100.56 MHz): δ 136.74 (s, C7a), 135.57 (s, C3a), 133.72
[(Ind)Pd(PPh3)(t-BuNC)][OTf] (12). 1H NMR (CDCl3, 300
MHz): δ 7.62-7.24 (m, protons of Ind and PPh3), 7.22-7.12 (m,
protons of Ind and PPh3), 7.10-6.95 (m, protons of Ind), 6.69 (br,
3
H2), 6.32 (d, JH-H ) 7.5 Hz, H4), 5.35 (br, H3), 1.15 (s, CNC-
(CH3)3). 31P{1H} NMR (CDCl3, 121.49 MHz): δ 30.05. 19F{1H}
NMR (CDCl3, 282.23 MHz): δ -78.2 (s). IR (KBr, cm-1): 2206
3
3
(s).
Dimerization of Ethylene Catalyzed by Complexes 7 and 8.
Ethylene was bubbled through CDCl3 solutions of 7 and 8 (20 mg
in 1 mL) for ca. 5 min prior to analysis by NMR. 1H NMR (CDCl3,
2
1
(d, JC-P ) 12.3 Hz, Cortho), 131.42 (s, Cpara), 130.09 (d, JC-P
)
3
45.5 Hz, Cipso), 129.06 (d, JC-P ) 9.9 Hz, Cmeta), 128.65 (s, C6),
127.65 (s, C5), 121.24 (s, C7), 117.65 (s, C4), 111.78 (s, C2), 102.51
(s, C1), 73.18 (s, C3). The 13C NMR resonance of the triflate group
could not be detected. 31P{1H} NMR (CDCl3, 161.92 MHz): δ
29.12 (s). 19F{1H} NMR (CDCl3, 376.31 MHz): δ -80.06 (s). Anal.
Calcd for C28H22O3F3PSPd: C, 53.13; H, 3.50; S, 5.07. Found: C,
53.06; H, 3.31; S, 4.69.
3
400 MHz): 1.61 (d, JH-H ) 5.0, CH3 of (Z)-butene), 1.64 (dd,
4
3JH-H ) 5.0 Hz, JH-H ) 1.2 Hz, CH3 of (E)-butene), 5.44 (m,
vinylic H for both (Z)- and (E)-butenes).
Dimerization of Styrene Catalyzed by Complexes 7 and 8.
Styrene (125 µL, 1 mmol) was added to a CDCl3 solution of 7 or
8 (10 mg in 1 mL), and the sample was placed in an ultrasonic
1
Synthesis of (1-Me-Ind)Pd(PPh3)(OTf) (8). A mixture of
(1-Me-Ind)Pd(PPh3)Cl (2; 450 mg, 0.84 mmol) and AgOTf (325
mg, 1.27 mmol) was stirred in CH2Cl2 (50 mL) for 2 h at room
temperature and filtered to remove AgCl. Evaporation of the filtrate
to dryness and crystallization of the residue from C6H6/hexane at
bath for 15 h to ensure mixing. Analysis by H NMR showed a
near-complete conversion of styrene to the dimer (Z)-1,3-diphenyl-
1
1-butene. H NMR (CDCl3, 400 MHz): δ 7.18-6.98 (m, protons
3
of Ph), 6.29 (br, PhCHd), 6.26 (dd, JH-H ) 1 and 6.1 Hz), 3.38
(quintuplet, JH-H ) 6.74 Hz, CH), 1.27 (d, JH-H ) 7.1 Hz, CH3).
1
room temperature gave a brown-red powder (430 mg, 79%). H
The GC/MS analysis of the NMR mixtures showed the presence
NMR (CDCl3, 400 MHz): δ 7.43-7.37 (m, PPh3), 7.32 (d, 2JH-H
•
of the dimer 1,3-diphenyl-1-butene (M•+, m/z 208; M•+ - CH3 ,
3
3
•
m/z 193; M•+ - PhH, m/z 130; M•+ - (PhH + CH3 ), m/z 115;
) 7.7 Hz, H7), 7.16 (t, JH-H ) 7.8 Hz, H6), 6.87 (t, JH-H ) 7.5
3
Hz, H5), 6.55 (br, H2), 6.13 (d, JH-H ) 7.3 Hz, H4), 4.54 (s, H3),
etc.), traces of styrene trimer for which the fragmentation pattern
was nearly identical with that of the dimer, with the exception of
the parent ion peak (M•+, m/z 312), and traces of IndC(Ph)dCH2
2.09 (d, JH-P ) 11.3 Hz, CH3). 31P{1H} NMR (CDCl3, 161.92
4
MHz): δ 31.39 (s). 19F{1H} NMR (CDCl3, 376.31 MHz): δ -80.51
•
(M•+, m/z 218; M•+ - CH3 , m/z 203; M•+ - C(Ph)dCH2, m/z
(s).
Ligand Substitution Reactions with 7. Substitution of the OTf
ligand in 7 by L was monitored by spectroscopy, without isolating
the resulting adducts. These reactions were carried out by adding
1 equiv of L to a 0.5 mL CDCl3 solution of 7 (ca. 0.03 mmol) in
an NMR tube. The NMR spectra of these samples were then
measured at room temperature. The data are given below.
115).
Reaction of Complex 7 with p-Fluorostyrene. This reaction
was carried out in CDCl3 at room temperature using 100 equiv of
p-fluorostyrene. After the sample was agitated in an ultrasonic bath
for 24 h, the mixture was subjected to NMR and GC/MS analyses
that showed complete conversion of the monomer to dimeric and
[(Ind)Pd(PPh3)2][OTf] (5[OTf]). 1H NMR (CDCl3, 300
MHz): δ 7.43-7.26 (m, PPh3 and protons of Ind), 7.12-7.02 (m,
PPh3 and protons of Ind), 6.19-6.22 (m, H4 and H7), 5.48-5.44
(m, H1 and H3). 13C{1H} NMR (CDCl3, 75.40 MHz): δ 133.77 (t,
1
trimeric species. H NMR (CDCl3, 400 MHz): δ 7.39-7.01 (m,
protons of Ph), 6.45-6.31 (m, CHd), 3.69 (quintuplet, JH-H
)
6.9 Hz, CH), 1.52, 1.34 (d, JH-H ) 7.1 Hz, CH3). The GC/MS
analysis of the sample showed the presence of the dimer (two
isomers, totaling 66%) and a trimer (34%). The fragmentation
patterns for the two isomers of the dimer were nearly identical:
1
2JC-P ) 5.9 Hz, Cortho), 131.68 (s, Cpara), 130.04 (d, JC-P ) 46
3
Hz, Cipso), 129.38 (pseudo t, JC-P ) 5.3 Hz, Cmeta), 128.38 (s, C5
M•+, m/z 244; M•+ - CH3 , m/z 229; M•+ - (CH3• + C6H5F), m/z
•
and C6), 118.88 (s, C4 and C7), 113.11 (s, C2), 95.35 (pseudo t,
2JC-P ) 11.6 Hz, C1 and C3). 31P{1H} NMR (CDCl3, 121.49
MHz): δ 27.73 (s). 19F{1H} NMR (CDCl3, 282.23 MHz): δ
-78.19 (s).
133; [FC6H4CH2]•+, m/z 109. The fragmentation pattern for the
trimer was nearly identical with that of the dimers, with the
exception of the parent ion peak (M•+, m/z 366).
[(Ind)Pd(PPh3)(PMe3)][OTf] (9). 31P{1H} NMR (C6D6, 161.92
MHz): δ 30.05 (d, 2JP-P ) 59.7 Hz), -16.66 (d, 2JP-P ) 59.7 Hz).
19F{1H} NMR (CDCl3, 376.31 MHz): δ -80.9 (s).
Reaction of Complex 7 with p-X-Styrenes (X ) NH2, Me,
OMe). The reaction of p-aminostyrene was carried out on an NMR
scale using 100 equiv of substrate (148 µL) in CDCl3, at room
temperature, for 24 h. The reactions with X ) Me, OMe were
carried out by stirring a mixture of 7 (ca. 20 mg, 0.0316 mmol)
and a large excess of the olefin (4.25 mL, 1000 equiv) in toluene
(4 mL) for 24 h at room temperature. Evaporation of the solvent
and unreacted styrene gave an off-white solid, which was isolated
and subjected to NMR and GPC analyses (in THF, relative to poly-
(styrene) standards), as follows. X ) NH2: 150 mg, 100% yield;
[(Ind)Pd(PPh3)(CH3CN)][OTf] (10). 1H NMR (CDCl3, 400
MHz): δ 7.55-7.45 (m, PPh3), 7.36-7.27 (m, PPh3), 7.16 (t, 3JH-H
) 7.6 Hz, H6), 7.05 (br, H1 and H7), 6.92 (t, 3JH-H ) 7.6 Hz, H5),
6.72 (pseudo t, 3JH-H ) 3.6 Hz, H2), 6.24 (d, 3JH-H ) 7.6 Hz, H4),
5.04 (br, H3), 2.07 (s, MeCN). 13C{1H} NMR (CDCl3, 100.56
2
MHz): δ 135.47 (s, C7a), 134.59 (s, C3a), 133.77 (d, JC-P ) 12.5
3
Hz, Cortho), 131.61 (s, Cpara), 129.28 (d, JC-P ) 11.09 Hz, Cmeta),
1
Mw ≈ 1050, Mw/Mn ≈ 1.3, Mw ≈ 1250; H NMR (CDCl3) δ 7.08
128.97 (s, C6), 128.04 (s, C5), 122.34 (s, C7), 118.92 (s, C4), 112.09
2
(br), 6.72-6.48 (m), 4.49 (br), 3.79 (br) 2.49 (br), 1.87 (br), 1.32
(br). X ) Me: 3.7 g, 88% yield; Mw/Mn ≈ 1.4; 1H NMR (CDCl3)
δ 7.33 (br), 6.59 (br), 2.55 (br), 1.46 (br). X ) OMe: 4.1 g, 96%
yield; Mw ≈ 29 000, Mw/Mn ≈ 3.2; 1H NMR (CDCl3) δ 6.62 (br),
3.79 (br), 1.82 (br), 1.42 (br).
(s, C2), 101.14 (d, JC-P ) 18.6 Hz, C1), 77.17 (s, C3), 3.14 (s,
CH3CN). 31P{1H} NMR (C6D6, 121.49 MHz): δ 31.05 (s). 19F{1H}
NMR (CDCl3, 376.31 MHz): δ -80.8 (s). IR (KBr, cm-1): 2291
(w), 2247 (w), 2186 (w).
[(Ind)Pd(PPh3)(PhCN)][OTf] (11). 1H NMR (CDCl3, 400
MHz): δ 7.63-7.34 (m, PPh3 and protons of Ind), 7.31-7.27 (m,
protons of Ind and PhCN), 7.19-7.15 (m, protons of Ind and
Reactivities of Complexes 7 and 8 with 1-Hexene. Monitoring
the reaction of 1-hexene (0.1 mL, 0.80 mmol, 1.6 M in CDCl3)
with complexes 7 and 8 (ca. 10 mg, 0.016 mmol, 0.032 M in CDCl3)
by 1H and 13C{1H} NMR spectroscopy indicated the slow formation
of (E)- and (Z)-2-hexenes (75:25) over 24 h. 13C{1H} NMR data
for (E)-2-hexene: δ 13.8, 18.0, 22.7, 34.9, 124.8 and 131.5. 13C{1H}
NMR data for (Z)-2-hexene: δ 12.8, 14.1, 25.7, 29.1, 123.9,
3
PhCN), 7.09-7.04 (m, protons of Ind and PhCN), 6.94 (t, JH-H
) 7.6 Hz, H5), 6.87 (pseudo t, 3JH-H ) 2.7 Hz, H2), 6.24 (d, 3JH-H
) 7.6 Hz, H4), 5.07 (br, H3). 31P{1H} NMR (C6D6, 121.49 MHz):
δ 30.97 (s). 19F{1H} NMR (CDCl3, 376.31 MHz): δ -80.6 (s). IR
(KBr, cm-1): 2227 (m).