Palladacyclic complexes containing C,N-type ligands as catalysts in cross-coupling reactions

Article abstract of DOI:10.1002/ejic.200800195

Four ligand precursors, namely PhN=C(CMe₂)(NPh)C=N(E) [E = -(CH₂)₂OMe (1); -(CH₂)C(O)OMe (2); -(CH ₂)₂CH3 (3); -C₆H₅ (4)], are described. Treatment of 1, 2, 3 or 4 with 1-1.1 molar equivalents of Pd(OAc)₂ in THF or CH₃CN affords the orthometallated palladium(II) complexes [{[PhN=C(CMe₂)-(N-η¹-Ph)C=N(E) ]Pd(OAc)}₂] [E = -(CH₂)₂OMe (5); -(CH ₂)-C(O)OMe (6); -(CH₂)₂CH₃ (7); -C₆H₅ (8)], respectively. The reaction of 5 or 6 with an excess of NaCl(aq.) in acetone affords the orthometallated palladium(II) complexes [{PhN=C(CMe₂)(N-η¹-Ph)C=N(E)}PdCl] [E = -(CH₂)₂OMe (9); -(CH₂)C(O)OMe (10)], whereas the reaction of 7 with an excess of NaCl(aq.) in acetone affords the dinuclear palladium(II) complex [{[PhN=C(CMe₂)(N-η¹-Ph)C= N(CH₂)₂CH₃]-PdCl}₂] (11). The crystal and molecular structures of compounds 2, 4, 5, 7, 8 and 9 are reported The application of those novel palladacyclic complexes to the Suzuki and Heck reactions with aryl halide substrates is examined. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Full text of DOI:10.1002/ejic.200800195

FULL PAPER
DOI: 10.1002/ejic.200800195
Palladacyclic Complexes Containing C,N-Type Ligands as Catalysts in Cross-
Coupling Reactions
Ming-Tsz Chen,[a] Chi-An Huang,[a] and Chi-Tien Chen*[a]
Keywords: Metallacycles / N ligands / Suzuki reaction / Heck reaction / Palladium
Four ligand precursors, namely PhN=C(CMe2)(NPh)C=N(E)
[E = –(CH2)2OMe (1); –(CH2)C(O)OMe (2); –(CH2)2CH3 (3);
–C6H5 (4)], are described. Treatment of 1, 2, 3 or 4 with 1–1.1
molar equivalents of Pd(OAc)2 in THF or CH3CN affords the
orthometallated palladium(II) complexes [{[PhN=C(CMe2)-
(N-η1-Ph)C=N(E)]Pd(OAc)}2] [E = –(CH2)2OMe (5); –(CH2)-
C(O)OMe (6); –(CH2)2CH3 (7); –C6H5 (8)], respectively. The
reaction of 5 or 6 with an excess of NaCl(aq.) in acetone
affords the orthometallated palladium(II) complexes
(9); –(CH2)C(O)OMe (10)], whereas the reaction of 7 with an
excess of NaCl(aq.) in acetone affords the dinuclear palladi-
um(II) complex [{[PhN=C(CMe2)(N-η1-Ph)C=N(CH2)2CH3]-
PdCl}2] (11). The crystal and molecular structures of com-
pounds 2, 4, 5, 7, 8 and 9 are reported The application of
those novel palladacyclic complexes to the Suzuki and Heck
reactions with aryl halide substrates is examined.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
[{PhN=C(CMe2)(N-η1-Ph)C=N(E)}PdCl] [E
= –(CH2)2OMe
Introduction
Results and Discussion
Syntheses and Characterisation of Ligand Precursors and
Palladacycles
Palladium-catalyzed cross-coupling reactions have at-
tracted a great deal of attention during the past few decades
mainly due to their widespread application in the formation
of carbon–carbon bonds between aryl or alkyl and aryl
groups.[1–15] Palladacycles bearing a metallated carbon
atom seem to be the most active catalyst precursors for the
promotion of such reactions,[1–6,8–10,12,14,15] therefore poten-
tial ancillary ligands that can serve as cyclometallated pre-
cursors are of current interest. The most common palladi-
um(II) complexes reported in the literature are five-mem-
bered ring palladacyclic species. Those complexes usually
form dinuclear species with bridged ligands or mono-nu-
clear species in the presence of a neutral donor group. We
have recently reported some six-membered ring pallada-
cycles.[16,17] The successful application of these complexes
in catalytic cross-coupling reactions encouraged us to study
the catalytic performance exhibited by palladacycles with
other functionalities. Following our previous work on four-
membered ring diimino palladacycles,[17] we report here the
synthesis and characterisation of novel palladacycles sup-
ported by different functionalities. Their catalytic activities
towards Suzuki and Heck reactions are also discussed.
Four new ligand precursors 1–4 were synthesized from
the reaction of 2,2-dimethyl-N,NЈ-diphenylpropanediimido-
yl dichloride with the appropriate amine or amine hydro-
chloride (2-methoxyethylamine for 1, glycine methyl ester
hydrochloride for 2, propylamine for 3, aniline for 4) in the
presence of excess NEt3 using a similar procedure to that
reported in the literature.[17] Compounds 1–4 were charac-
terised by NMR spectroscopy and elemental analysis, which
indicated four-membered ring diimine compounds with dif-
ferent functionalities. A summary of the syntheses and pro-
posed structures is shown in Scheme 1. The X-ray struc-
tures of 2 and 4 show four-membered diimine compounds
bearing different pendant functionalities. Their molecular
structures are depicted in Figures 1 and 2, respectively. The
bond lengths and bond angles around the imino C and N
atoms are indicative of significant double bond character
and an sp2 character of the carbon centres.
Treatment of 1, 2, 3 or 4 with one molar equivalent of
Pd(OAc)2 at room temperature or under reflux yielded
complexes 5, 6, 7 or 8, respectively, in high yield. Similar
to the results reported previously, signals correlating to the
metallated carbon atom were found in the 13C{1H} NMR
spectra in each case, thus indicating the formation of palla-
dacycles. Only one signal corresponding to the OAc ligand
is observed in the NMR spectra of those OAc-containing
palladacycles, thereby indicating an anti configura-
tion,[18a,18b] which is consistent with the observation in the
solid state.
[a] Department of Chemistry, National Chung Hsing University,
Taichung 402, Taiwan, Republic of China
E-mail: ctchen@dragon.nchu.edu.tw
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Palladacyclic Complexes as Catalysts in Cross-Coupling Reactions
Scheme 1.
Figure 2. Molecular structure of 4. Selected bond lengths [Å] and
bond angles [°]: N(1)–C(1) 1.424(3), N(3)–C(11) 1.261(3), N(1)–
C(7) 1.251(3), N(2)–C(18) 1.418(3), N(2)–C(7) 1.409(3), N(3)–
C(12) 1.420(3), N(2)–C(11) 1.403(3); N(1)–C(7)–N(2) 126.98(19),
N(3)–C(11)–C(8) 140.9(2), N(1)–C(7)–C(8) 141.89(19), N(2)–
C(11)–C(8) 91.93(16), N(2)–C(7)–C(8) 91.02(16), C(7)–N(1)–C(1)
121.99(19), C(7)–C(8)–C(11) 83.48(15), C(11)–N(3)–C(12) 121.1(2),
N(3)–C(11)–N(2) 127.1(2). Hydrogen atoms on carbon atoms have
been omitted for clarity.
Figure 1. Molecular structure of 2. Selected bond lengths [Å] and
bond angles [°]: N(1)–C(1) 1.427(3), N(3)–C(11) 1.256(3), N(1)–
C(7) 1.262(3), N(2)–C(15) 1.417(3), N(2)–C(7) 1.403(3), N(3)–
C(12) 1.456(3), N(2)–C(11) 1.411(3); N(1)–C(7)–N(2) 128.4(2),
N(3)–C(11)–C(8) 140.6(2), N(1)–C(7)–C(8) 139.6(2), N(2)–C(11)–
C(8) 91.34(18), N(2)–C(7)–C(8) 91.92(18), C(7)–N(1)–C(1)
120.5(2), C(7)–C(8)–C(11) 83.20(18), C(11)–N(3)–C(12) 116.3(2),
N(3)–C(11)–N(2) 128.1(2). Hydrogen atoms on carbon atoms have
been omitted for clarity.
planar geometry to one phenyl ring carbon atom, one imine
nitrogen atom and two bridging acetate oxygen atoms. The
Crystals of 5, 7 and 8 suitable for a structural determi- N–Pd–Cmetallated bite angles [92.98(11)° for 5; 93.10(11)°
nation were obtained from CH2Cl2/hexane solution. The and 93.76(11)° for 7; 91.78(14)° and 92.71(14)° for 8] re-
molecular structures are depicted in Figures 3, 4 and 5, sulting from the imino nitrogen and the metallated carbon
respectively. These palladacycles are found to be dinuclear are similar to those [93.20(10)°, 93.77(8)°, 94.51(10)°,
species with two acetates as bridging ligands. Each palla- and 93.47(12)°] found in our previous work.[17] The
dium atom is coordinated in a slightly distorted square- Pd–Cmetallated bond lengths [1.984(3) Å for 5; 1.995(3) and
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M.-T. Chen, C.-A. Huang, C.-T. Chen
FULL PAPER
2.002(3) Å for 7; 1.988(4) and 2.004(4) Å for 8] are similar
to those found in related palladacycles with a metallated
carbon atom [1.948(4)–2.061(3) Å].[16,17,19] The Pd–NC=N
bond lengths [2.020(3) Å for 5; 2.015(3) and 2.024(3) Å
for 7; 2.030(3) and 2.021(3) Å for 8] are also similar
to those found in other palladacycles [1.981(3)–
2.111(4) Å].[16,17,19a,19d,19e,19h–19j] The Pd–OOAc bond
lengths [2.037(2) and 2.143(2) Å for 5; 2.048(2), 2.142(2),
2.048(2) and 2.158(2) Å for 7; 2.041(3), 2.126(3), 2.042(3)
and 2.131(3) Å for 8] are similar to those found in the litera-
ture [2.033(3)–2.160(3) Å].[19e,19f,20,21] Due to the trans in-
fluence of the nitrogen atoms, the palladium–oxygen bonds
are shorter than those trans to the palladium–carbon
bonds.
Figure 4. Molecular structure of 7. Selected bond lengths [Å] and
bond angles [°]: Pd(1)–Pd(2) 2.9409(4), Pd(1)–C(20) 1.995(3),
Pd(2)–C(42) 2.002(3), Pd(1)–N(3) 2.015(3), Pd(2)–N(6) 2.024(3),
Pd(1)–O(1) 2.048(2), Pd(2)–O(2) 2.158(2), Pd(1)–O(4) 2.142(2),
Pd(2)–O(3) 2.048(2), C(15)–C(20) 1.389(4), C(42)–C(37) 1.402(4),
C(15)–N(2) 1.415(4), C(37)–N(5) 1.415(4), N(3)–C(11) 1.258(4),
N(6)–C(33) 1.265(4); C(20)–Pd(1)–N(3) 93.10(11), C(42)–Pd(2)–
N(6) 93.76(11), C(20)–Pd(1)–O(1) 90.48(12), C(42)–Pd(2)–O(3)
91.41(12),
174.45(10), C(20)–Pd(1)–O(4) 173.24(11), C(42)–Pd(2)–O(2)
172.04(11), N(3)–Pd(1)–O(4) 92.32(10), N(6)–Pd(2)–O(2)
N(3)–Pd(1)–O(1)
176.31(10),
N(6)–Pd(2)–O(3)
92.17(10), O(1)–Pd(1)–O(4) 84.17(11), O(3)–Pd(2)–O(2) 82.50(11).
Hydrogen atoms on carbon atoms have been omitted for clarity.
Figure 3. Molecular structure of 5. Selected bond lengths [Å] and
bond angles [°]: Pd–Pd(A) 2.9289(7), Pd–C(20) 1.984(3), Pd–N(3)
2.020(3), Pd–O(1) 2.037(2), Pd–O(2A) 2.143(2), C(15)–C(20)
1.392(4), C(15)–N(2) 1.406(4), N(3)–C(11) 1.254(4); C(20)–Pd–
N(3) 92.98(11), C(20)–Pd–O(1) 91.16(11), N(3)–Pd–O(1)
175.32(11),
C(20)–Pd–O(2A)
173.86(11),
N(3)–Pd–O(2A)
92.24(10), O(1)–Pd–O(2A) 83.50(10). Hydrogen atoms on carbon
atoms have been omitted for clarity.
The reactions of 5, 6 or 7 with an excess of aqueous
sodium chloride in acetone at room temperature yielded 9,
10 or 11, respectively, as yellow solids.[21] Compounds 9–
11 were characterized by NMR spectroscopy and elemental
analysis. Crystals of 9 suitable for a structural determi-
nation were obtained from concentrated chloroform solu-
tion. The molecular structure is shown in Figure 6. Com-
pound 9 is mononuclear with a coordinated Cl instead of
Figure 5. Molecular structure of 8. Selected bond lengths [Å] and
bond angles [°]: Pd(1)–Pd(2) 3.0818(8), Pd(1)–C(23) 1.988(4),
Pd(2)–C(44) 2.004(4), Pd(1)–N(3) 2.030(3), Pd(2)–N(6) 2.021(3),
Pd(1)–O(1) 2.041(3), Pd(2)–O(2) 2.131(3), Pd(1)–O(4) 2.126(3),
Pd(2)–O(3) 2.042(3), C(18)–C(23) 1.387(5), C(43)–C(44) 1.394(5),
C(18)–N(2) 1.427(5), C(43)–N(5) 1.422(5), N(3)–C(11) 1.274(5),
N(6)–C(36) 1.268(5); C(23)–Pd(1)–N(3) 91.78(14), C(44)–Pd(2)–
OAc for those palladacycles with tridentate ligands, N(6) 92.71(14), C(23)–Pd(1)–O(1) 89.39(14), C(44)–Pd(2)–O(3)
89.94(14),
175.68(13), C(23)–Pd(1)–O(4) 174.37(14), C(44)–Pd(2)–O(2)
172.49(14), N(3)–Pd(1)–O(4) 91.47(12), N(6)–Pd(2)–O(2)
90.16(11), O(1)–Pd(1)–O(4) 87.23(12), O(2)–Pd(2)–O(3) 86.81(12).
Hydrogen atoms on carbon atoms have been omitted for clarity.
N(3)–Pd(1)–O(1)
178.06(12),
N(6)–Pd(2)–O(3)
whereas compound 11 is a dinuclear species with two chlo-
rides as bridging ligands due the lack of pendant function-
ality. The bond lengths and bond angles are similar to those
discussed above The Pd–Cl bond length [2.3158(8) Å] is at
the lower end of those [2.3181(2)–2.3999(7) Å] found for
palladacycles containing tridentate ligands.[17a,19a,19f–19h,19k] Attempts to synthesize a palladium chloride complex con-
The Pd–OOMe bond length [2.204(2) Å] is similar to those taining ligand 4 by a similar route proved unsuccessful due
[2.192(4)–2.276(3) Å] found for other palladacycles.[22] to the poor solubility of the products.
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Palladacyclic Complexes as Catalysts in Cross-Coupling Reactions
tivities after testing palladacycles 6–9 and 11 with an elec-
tronically deactivated aryl bromide under the optimised
conditions (entries 8–12). Both compounds also showed
catalytic activities in the reaction with he electronically acti-
vated aryl chloride with a 1 mol-% catalyst loading, al-
though poor conversions were observed after 2 or 3 h (en-
tries 13–14). A similar reaction with 2 mol-% catalyst load-
ing was applied to examine the electronically deactivated
aryl chloride. Poor conversion was found after 12 h (entry
15).
Figure 6. Molecular structure of 9. Selected bond lengths [Å] and
bond angles [°]: Pd–C(20) 1.996(3), N(2)–C(15) 1.423(3), Pd–O
2.204(2), Pd–Cl 2.3158(8), N(1)–C(7) 1.252(4), Pd–N(3) 2.008(2);
C(20)–Pd–N(3) 93.85(11), C(20)–Pd–Cl 96.47(8), N(3)–Pd–O
78.51(10), O–Pd–Cl 91.16(6), C(20)–Pd–O 172.33(10), N(3)–Pd–Cl
169.59(7). Hydrogen atoms on carbon atoms have been omitted for
clarity.
Scheme 2. Application of the palladacycles in the Suzuki reaction.
In order to examine the catalytic activity in alcoholic sol-
vents,[23] compound 8, which was found to be a better pre-
catalyst, was tested in three alcoholic solvents and water.
Excellent conversions were observed within 20 min in the
Catalytic Studies
With the aim of comparing the reactivity of these com- three alcohols and 30 min in water (entries 16–19). Due to
plexes with related C,N-type palladacycles, we chose the Su- the improvement of catalytic activities in the cross-coupling
zuki reaction, as shown in Scheme 2. The potential catalyst by the biphasic system,[24] compounds 7 and 8 were used to
precursors 5–11 were tested in the coupling of 4-bromoace- examine the catalytic activities with an electronically deacti-
tophenone with phenylboronic acid at room temperature vated aryl bromide with 1 mol-% catalyst loading and an
within 1 h on a 1 mol-% scale. The optimised conditions optimized volume ratio of DMF/H2O (1:1; entries 20 and
were found to be K3PO4/DMA for 5 and 9 (entries 1 and 21). The conversions were up to 99% within 15 min in both
5), K3PO4/toluene for 6, 10 and 11 (entries 2, 6 and 7), and cases. This improvement encouraged us to examine the
KF/THF for 7 and 8 (entries 3 and 4). Selected results are catalytic activities of both compounds with an electronically
listed in Table 1. Compounds 7 and 8 exhibited better ac- activated aryl chloride. Compound 8 exhibited better con-
Table 1. Suzuki coupling reaction catalyzed by new palladium complexes.[a]
Entry Catalyst
Aryl halide
Base
Solvent
[Pd] [mol-%]
T [h]
Conv. [%][b]
Yield [%][c]
1
2
3
4
5
6
7
8
5
4-bromoacetophenone
4-bromoacetophenone
4-bromoacetophenone
4-bromoacetophenone
4-bromoacetophenone
4-bromoacetophenone
4-bromoacetophenone
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
K3PO4
K3PO4
KF
DMA
toluene
THF
THF
DMA
toluene
toluene
toluene
THF
THF
DMA
toluene
THF
THF
THF
MeOH
EtOH
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
2
1.75
1.75
3
3
2
84
99
99
99
99
67
99
95
96
95
42
33
20
73
65
99
94
99
88
99
99
77
94
84
90
79
97
95
96
94
–
93
90
93
91
–
–
–
–
–
94
89
95
86
96
94
73
88
78
85
6
7
8
KF
9
K3PO4
K3PO4
K3PO4
K3PO4
KF
KF
K3PO4
K3PO4
10
11
6
9
7
10
11
12
13
14
15
16
17
18
19
20[d]
21[d]
22[d]
23[d]
24[d]
25[d,e]
8
9
11
7
methyl 4-chlorobenzoate KF
methyl 4-chlorobenzoate KF
8
3
12
8
4-chloroanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoacetophenone
4-bromoanisole
4-bromoanisole
methyl 4-chlorobenzoate Cs2CO3
methyl 4-chlorobenzoate Cs2CO3
4-chloroanisole
4-chloroanisole
KF
8
Cs2CO3
K3PO4
K3PO4
Cs2CO3
Cs2CO3
Cs2CO3
20 min
20 min
20 min
30 min
15 min
15 min
3
1.5
90
4
8
8
IPA
H2O
8
8
DMF/H2O
DMF/H2O
DMF/H2O
DMF/H2O
DMF/H2O
DMF/H2O
7
7
8
8
Cs2CO3
Cs2CO3
8
[a] Reaction conditions: 1.0 mmol aryl halide, 1.5 mmol phenylboronic acid, 2 mmol base, 2 mL solvent, room temperature. [b] Deter-
1
mined by H NMR spectroscopy. [c] Isolated yield (average of two experiments). [d] Volume ratio = 1:1. [e] 60 °C.
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M.-T. Chen, C.-A. Huang, C.-T. Chen
FULL PAPER
version within 1.5 h under the same conditions (entries 22 catalyst concentration (catalyst/substrate ratio of 10–3) led
and 23). Similar conditions were applied to examine the to a conversion of 95% within 3 h (entry 17), whereas a
electronically deactivated aryl chloride. A similar conver- catalyst/substrate ratio of 10–6 gave a turnover of up to
sion was obtained after 90 h (entry 24), although a higher 5.5ϫ105 during a 48 h period for the coupling of an elec-
conversion can be achieved within 4 h with 3 mol-% catalyst tronically activated aryl bromide (entry 18).
loading at 60 °C (entry 25). Compared with our previous
work on palladacycles containing a four-membered diimine
system,[17b] the CN-type palladacycles in this report demon-
strate better catalytic activities for the Suzuki reaction. Un-
der the optimised conditions, the dinuclear palladacycle 8
exhibits comparable catalytic activities in both alcoholic
and biphasic systems compared with those found in the lit-
erature.[23,24] In some cases, compound 8 even shows a
higher activity.
Compounds 5–11 were also examined as pre-catalysts in
the Heck coupling reaction of 4-bromoanisole with styrene
at 135 °C within 5 h on 1 mol-% Pd scale, as shown in
Scheme 3. The optimised conditions were found to be
K3PO4/DMA for 5, 6 and 11 (entries 1, 2 and 7), K3PO4/
DMF for 7 and 10 (entries 3 and 6), Cs2CO3/DMF for 8
(entry 4) and Cs2CO3/DMA for 9 (entry 5). Selected results
are listed in Table 2. The optimised conditions were used to
examine the catalytic activities of pre-catalysts 6–11 with an
electronically activated aryl chloride with 1 mol-% catalyst
loading within 12 h (entries 8–13). Due to the better conver-
sion exhibited by 9 (entry 11), this complex was chosen to
examine the catalytic activities with electronically activated
(entry 14) or electronically deactivated cases (entries 15 and
16). Good conversions were obtained within 1–5 h. A lower
An enhancement of conversion was observed upon add-
ing 1 mmol tetra-n-butylamine bromide (n-Bu4NBr, TBAB)
as co-catalyst (entries 11 and 19).[25] The same conditions
were applied to the reaction with an electronically deacti-
vated aryl chloride, with conversions of up to 94% within
24 h on 2 mol-% catalyst scale (entry 20). Compared with
our previous work on palladacycles containing a four-mem-
bered diimine system,[17] palladacycle 9 demonstrates better
catalytic activities than those with different functionalities
for the Heck reaction. Under optimised conditions, com-
pound 9 exhibits comparable activity in catalysing electroni-
cally deactivated aryl chloride with styrene, although with
lower amounts of TBAB compared with some pallada-
cycles.[12,15]
In summary, seven novel palladacycles bearing different
functionalities have been prepared and have demonstrated
catalytic activities for the Suzuki and Heck C–C coupling
reactions. Under optimised conditions, the dinuclear palla-
dacycle 8 exhibits better catalytic activities in the Suzuki
coupling reaction whereas the mononuclear palladacycle 9
exhibits better catalytic activities in the Heck coupling reac-
tion. A dramatic increase in activity was observed for the
Suzuki coupling reaction when using a biphasic system. The
pre-catalyst also shows excellent activity in catalysing the
reaction between an electronically deactivated aryl chloride
and phenylboronic acid under mild conditions. For the
Heck coupling reaction, complex 9 demonstrates compar-
able activity in catalysing the reaction between an electroni-
cally deactivated aryl chloride and styrene at 135 °C. This
might be due to the thermal stability of palladacycles with
Scheme 3. Application of the palladacycles in the Heck reaction.
Table 2. Heck coupling reaction catalyzed by new palladium complexes.[a]
Entry Catalyst Aryl halide
Base
Solvent
[Pd] [mol-%]
T [h]
Conv. [%][b]
Yield [%][c]
1
2
3
4
5
6
7
8
5
6
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-bromoanisole
4-chloroacetophenone
4-chloroacetophenone
4-chloroacetophenone
4-chloroacetophenone
4-chloroacetophenone
4-chloroacetophenone
4-bromoacetophenone
4-bromotoluene
K3PO4
K3PO4
K3PO4
Cs2CO3
Cs2CO3
K3PO4
K3PO4
K3PO4
K3PO4
Cs2CO3
Cs2CO3
K3PO4
K3PO4
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
DMA
DMA
DMF
DMF
DMA
DMF
DMA
DMA
DMF
DMF
DMA
DMF
DMA
DMA
DMA
DMA
DMA
DMA
DMA
DMA
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
5
5
5
5
5
5
5
12
12
12
12
12
12
1
3.5
5
3
62
97
97
99
97
92
89
44
26
20
62
33
28
98
95
97
95
55
91
94
–
90
91
95
92
87
83
–
–
–
–
–
7
8
9
10
11
6
9
7
10
11
12
13
14
15
16
17
18
19[d]
20[d]
8
9
10
11
9
–
92
90
92
90
–
86
90
9
9
4-bromoanisole
1
0.1
0.0001
1
9
4-bromoacetophenone
4-bromoacetophenone
4-chloroacetophenone
4-chloroanisole
9
48
12
24
9
9
2
[a] Reaction conditions: 1.0 mmol aryl halide, 1.3 mmol styrene, 1.5 mmol base, 2 mL solvent, 135 °C. [b] Determined by 1H NMR
spectroscopy. [c] Isolated yield (average of two experiments). [d] 1 mmol of NBu4Br added.
3146
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 3142–3150

Palladacyclic Complexes as Catalysts in Cross-Coupling Reactions
157.5, 161.1, 170.8 (two Cipso-C6H5, two C=N, and one C=O) ppm.
C20H21N3O2 (335.40): calcd. C 71.62, H 6.31, N 12.53; found C
71.52, H 6.06, N 12.44.
terdentate ligands. Preliminary studies on fine-tuning the
ligands and further application of these metal complexes to
catalytic reactions are currently underway.
PhN=CA(CBMe2)(NBPh)CC=N(CH2)2CH3(CA–NB)(CB–CC) (3):
The procedure for the preparation of 3 was similar to that used for
1 but with 2,2-dimethyl-N,NЈ-diphenylpropanediimidoyl dichloride
(1.19 g, 3.74 mmol), NEt3 (2.08 mL, 14.95 mmol) and propylamine
(0.92 mL, 11.2 mmol). A white solid was obtained. Yield: 0.92 g
(81.0 %). 1H NMR (600 MHz): δ = 0.98 [t, J = 7.2 Hz, 3 H,
(CH2)2CH3], 1.44 [s, 6 H, C(CH3)2], 1.65 [m, J = 7.2 Hz, 2 H,
(CH2)2CH3], 3.36 [t, J = 7.2 Hz, 2 H, (CH2)2CH3], 6.94 (d, J =
7.2 Hz, 2 H, o-Ph), 7.06 (t, J = 7.8 Hz, 1 H, p-Ph), 7.12 (t, J =
7.2 Hz, 1 H, p-Ph), 7.28 (t, J = 7.8 Hz, 2 H, m-Ph), 7.37 (t, J =
7.8 Hz, 2 H, m-Ph), 8.30 (d, J = 7.8 Hz, 2 H, o-Ph) ppm. 13C{1H}
NMR (150 MHz): δ = 11.9 [s, CH2CH2CH3], 21.7 [s, C(CH3)2],
25.0 (s, CH2CH2CH3), 50.4 (s, CH2CH2CH3), 58.0 [s, C(CH3)2],
119.3, 121.6, 123.2, 124.2, 128.6 (overlap, CH-C6H5), 137.5, 147.0,
157.2, 158.3 (two Cipso-C6H5 and two C=N) ppm. C20H23N3
(305.42): calcd. C 78.65, H 7.59, N 13.76; found C 78.49, H 7.23,
N 13.84.
Experimental Section
General: All manipulations were carried out under an atmosphere
of dinitrogen using standard Schlenk-line or dry-box techniques.
Solvents were refluxed over the appropriate drying agent and dis-
tilled prior to use. Methanol, ethanol, isopropyl alcohol, acetone,
DMA (dimethyl acetamide) and DMF (dimethyl foramide) were
used as supplied. Deuterated solvents were dried with molecular
sieves.
1H and 13C{1H} NMR spectra were recorded with either a Varian
Mercury-400 (400 MHz) or a Varian Inova-600 (600 MHz) spec-
trometer in [D]chloroform at ambient temperature unless stated
otherwise. The spectra were referenced internally to the residual
solvent peak and reported as parts per million relative to tet-
ramethylsilane. Elemental analyses were performed with an Ele-
mentar Vario ELIV instrument. Mass spectra were recorded with
a Finnigan/Thermo Quest MAT 95XL spectrometer.
PhN=CA(CBMe2)(NBPh)CC=NPh(CA–NB)(CB–CC) (4): The pro-
cedure for the preparation of 4 was similar to that used for 1 but
with 2,2-dimethyl-N,NЈ-diphenylpropanediimidoyl dichloride
(2.07 g, 6.49 mmol), NEt3 (3.62 mL, 26 mmol) and aniline
(1.77 mL, 19.5 mmol). A pale-yellow solid was obtained. Yield:
Propylamine (Acros), 2-methoxyethylamine (Acros), glycine
(RDH), aniline (Acros), tetra-n-butylammonium bromide (TCI),
and Pd(OAc)2 (Acros) were used as supplied. NEt3 was dried with
CaH2 and distilled before use. 2,2-Dimethyl-N,NЈ-diphenylmalona-
mide and 2,2-dimethyl-N,NЈ-diphenylpropanediimidoyl dichloride
were prepared by a literature method.[17]
1
1.98 g (89.8%). H NMR (600 MHz): δ = 1.22 [s, 6 H, C(CH3)2],
6.92 (d, J = 7.2 Hz, 4 H, o-Ph), 7.05 (t, J = 7.2 Hz, 2 H, p-Ph),
7.19 (t, J = 7.5 Hz, 1 H, p-Ph), 7.26 (t, J = 7.5 Hz, 4 H, m-Ph),
7.41 (t, J = 7.8 Hz, 2 H, m-Ph), 8.37 (d, J = 7.8 Hz, 2 H, o-Ph)
ppm. 13C{1H} NMR (150 MHz): δ = 22.4 (s, CH3), 59.3 [s,
C(CH3)2], 119.5, 121.3, 123.4, 124.8, 128.6, 128.8 (o, m, p-C6H5),
137.0, 146.5, 158.1 (two Cipso-C6H5 and one C=N) ppm. C23H21N3
(339.43): calcd. C 81.38, H 6.24, N 12.38; found C 80.88, H 6.57,
N 12.43.
PhN=CA(CBMe2)(NBPh)CC=N(CH2)2OMe(CA–NB)(CB–CC) (1):
2-Methoxyethylamine (1.1 mL, 12 mmol) was added to a flask con-
taining 2,2-dimethyl-N,NЈ-diphenylpropanediimidoyl dichloride
(1.27 g, 4.0 mmol) and NEt3 (2.23 mL, 16 mmol) in 40 mL of
CH2Cl2 at 0 °C. The reaction mixture was warmed to room tem-
perature and stirred overnight. After 14 h of stirring, the volatiles
were pumped off and the residue was extracted with 30 mL of hex-
ane to afford a white solid. Yield: 0.99 g (77.3 %). 1H NMR
(600 MHz): δ = 1.43 [s, 6 H, C(CH3)2], 3.38 (s, 3 H, OMe), 3.58
[m, 4 H, (CH2)2], 6.91 (d, J = 7.2 Hz, 2 H, o-Ph), 7.05 (t, J =
7.2 Hz, 1 H, p-Ph), 7.11 (t, J = 7.2 Hz, 1 H, p-Ph), 7.26 (t, J =
7.8 Hz, 2 H, m-Ph), 7.35 (t, J = 7.8 Hz, 2 H, m-Ph), 8.26 (d, J =
7.8 Hz, 2 H, o-Ph) ppm. 13C{1H} NMR (150 MHz): δ = 21.6 [s,
C(CH3)2], 48.5 [s, (CH2)2], 58.0 [s, tert-C(CH3)2], 59.1 (s, OCH3),
73.1 [s, (CH2)2], 119.4, 121.5, 123.3, 124.4, 128.6 (overlap, o, m, p-
C6H5), 137.3, 146.8, 158.1, 158.9 (two Cipso-C6H5 and two C=N)
ppm. C20H23N3O (321.42): calcd. C 74.74, H 7.21, N 13.07; found
C 74.75, H 7.46, N 12.85.
PhN=CA(CBMe2)(NBPh)CC=NCH2C(O)OMe(CA–NB)(CB–CC)
(2): Glycine methyl ester hydrochloride (3.01 g, 24 mmol) was
added to a flask containing 2,2-dimethyl-N,NЈ-diphenylpropanedii-
midoyl dichloride (2.54 g, 8.0 mmol) and NEt3 (4.46 mL, 32 mmol)
in 40 mL of CH2Cl2 at 0 °C. The reaction mixture was warmed to
room temperature and stirred overnight. After 14 h of stirring, the
volatiles were pumped off and the residue was extracted with 30 mL
of toluene to afford a pale-yellow solid. Yield: 2.45 g (92.0%). H
NMR (600 MHz): δ = 1.44 [s, 6 H, C(CH3)2], 3.77 [s, 3 H, C(=O)-
OCH3], 4.24 (s, 2 H, CH2), 6.93 (d, J = 7.2 Hz, 2 H, o-Ph), 7.08 (t,
[{[PhN=CA(CBMe2)(NB-η1-C6H4)CC=N(CH2)2OMe(CA–NB)(CB–
CC)]Pd(OAc)}2] (5): THF (30 mL) was added to a flask containing
Pd(OAc)2 (0.29 g, 1.3 mmol) and 1 (0.42 g, 1.3 mmol) at room tem-
perature. After 10 d of stirring, the reaction mixture was filtered
and the filtrate was pumped to dryness to afford a yellow solid.
Yield: 0.52 g (82.2 %). 1H NMR (600 MHz): δ = 0.96 [s, 6 H,
C(CH3)2], 1.24 [s, 6 H, C(CH3)2], 2.11 [s, 6 H, O-C(=O)-CH3], 2.69
(m, 2 H, CH2), 2.90 (m, 2 H, CH2), 3.27 (s, 6 H, OMe), 3.55 (m,
2 H, CH2), 3.73 (m, 2 H, CH2), 6.90 (t, J = 6.6 Hz, 2 H, CH-Ph),
6.93 (d, J = 7.2 Hz, 4 H, CH-Ph), 7.06 (t, J = 7.2 Hz, 2 H, CH-
Ph), 7.09 (t, J = 7.2 Hz, 2 H, CH-Ph), 7.28 (t, J = 7.8 Hz, 4 H,
CH-Ph), 7.39 (d, J = 7.8 Hz, 2 H, CH-Ph), 8.09 (d, J = 7.8 Hz, 2
H, CH-Ph) ppm. 13C{1H} NMR (150 MHz): δ = 21.1 [s,
C(CH3)2], 21.5 [s, C(CH3)2], 24.6 [s, O-C(=O)-CH3], 50.4 (s, CH2),
57.3 [s, C(CH3)2], 59.0 (s, OCH3), 72.2 (s, CH2), 116.2, 121.1, 123.8,
123.9, 124.6, 128.9, 134.7 (CH-C6H5), 120.8, 130.7, 145.8, 154.9,
159.0 (one η1-Ph, two Cipso-C6H5 and two C=N), 180.6 [s, O-
C(=O)-CH3] ppm. C44H50N6O6Pd2 (971.74): calcd. C 54.38, H
5.19, N 8.65; found C 54.42, H 4.92, N 8.58.
[{[PhN=CA(CBMe2)(NB-η1-C6H4)CC=NCH2C(O)OMe(CA–NB)-
(CB–CC)]Pd(OAc)}2] (6): THF (30 mL) was added to a flask con-
taining Pd(OAc)2 (0.67 g, 3.0 mmol) and 2 (0.91 g, 2.7 mmol) at
room temperature. After 24 h of refluxing, the reaction mixture was
1
J = 7.2 Hz, 1 H, p-Ph), 7.16 (t, J = 7.8 Hz, 1 H, p-Ph), 7.29 (t, J filtered and the filtrate was pumped to dryness. The residue was
= 7.8 Hz, 2 H, m-Ph), 7.39 (t, J = 7.8 Hz, 2 H, m-Ph), 8.28 (d, J =
washed with 15 mL of toluene to afford a reddish-brown solid.
7.8 Hz, 2 H, o-Ph) ppm. 13C{1H} NMR (150 MHz): δ = 21.5 [s,
Yield: 1.22 g (90.4 %). 1H NMR (600 MHz): δ = 0.89 [s, 6 H,
C(CH3)2], 50.2 (s, CH2), 52.2 [s, C(=O)OCH3], 58.0 [s, C(CH3)2], C(CH3)2], 1.20 [s, 6 H, C(CH3)2], 2.06 [s, 6 H, OC(=O)CH3], 3.18
119.6, 121.4, 123.4, 124.7, 128.7 (overlap, CH-C6H5), 136.9, 146.6, (d, J = 16.8 Hz, 2 H, CH2), 3.60 (d, J = 17.4 Hz, 2 H, CH2), 3.76
Eur. J. Inorg. Chem. 2008, 3142–3150
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3147

M.-T. Chen, C.-A. Huang, C.-T. Chen
FULL PAPER
(s, 6 H, OCH3), 6.91 (d, J = 7.8 Hz, 4 H, CH-Ph), 6.97 (t, J =
6.6 Hz, 2 H, CH-Ph), 7.07 (t, J = 7.2 Hz, 2 H, CH-Ph), 7.12 (t, J
= 7.2 Hz, 2 H, CH-Ph), 7.31 (t, J = 7.8 Hz, 4 H, CH-Ph), 7.38 (d,
J = 8.4 Hz, 2 H, CH-Ph), 8.05 (d, J = 7.8 Hz, 2 H, CH-Ph) ppm.
13C{1H} NMR (150 MHz): δ = 20.6 [s, C(CH3)2], 20.8 [s, C-
[{PhN=CA(CBMe2)(NB-η1-C6H4)CC=NCH2C(O)OMe(CA–NB)-
(CB–CC)}PdCl] (10): The procedure for the preparation of 10 was
similar to that used for 9 but with 6 (0.72 g, 0.74 mmol), 20 mL of
saturated NaCl(aq.) and 15 mL of acetone. A yellow solid was ob-
tained. Yield: 0.48 g (68.6%). 1H NMR [600 MHz, (CD3)2SO]: δ =
(CH3)2], 24.3 [s, O-C(=O)-CH3], 50.7 (s, CH2), 52.4 [s, C(=O)- 1.38 [s, 6 H, C(CH3)2], 3.72 (s, 3 H, OCH3), 4.31 (s, 2 H, CH2),
OCH3], 57.2 [s, C(CH3)2], 116.3, 120.8, 124.2, 124.4, 124.7, 129.0, 6.80 (m, 1 H), 7.02 (m, 3 H), 7.14 (t, J = 7.5 Hz, 1 H, CH-Ph),
135.0 (CH-C6H5), 121.2, 130.8, 145.4, 154.1, 160.1 (one η1-Ph, two
7.36 (t, J = 7.8 Hz, 2 H, CH-Ph), 7.91 (d, J = 7.2 Hz, 1 H, CH-
Cipso-C6H5 and two C=N), 168.8, 181.3 [two C(=O)] ppm. Ph), 7.93 (d, J = 7.8 Hz, 1 H, CH-Ph) ppm. 13C{1H} NMR
C44H46N6O8Pd2 (999.71): calcd. C 52.86, H 4.64, N 8.41; found C
53.43, H 4.63, N 8.17.
(150 MHz, (CD3)2SO): δ = 20.2 [s, C(CH3)2], 49.7 (s, CH2), 52.2 (s,
OCH3), 115.5, 120.8, 123.4, 124.0, 124.3, 128.9, 140,9 (CH-C6H5),
118.5, 130.9, 145.4, 154.2, 160.8, 170.5 [one C(=O), one η1-Ph, two
Cipso-C6H5 and two C=N] ppm. C20H20ClN3O2Pd (476.26): calcd.
C 50.44, H 4.23, N 8.82; found C 50.20, H 4.35, N 8.59.
[{[PhN=CA(CBMe2)(NB-η1-C6H4)CC=N(CH2)2CH3(CA–NB)(CB–
CC)]Pd(OAc)}2] (7): The procedure for the preparation of 7 was
similar to that used for 6 but with Pd(OAc)2(1.12 g, 5 mmol) and
3 (1.37 g, 4.5 mmol). A yellow solid was obtained. Yield: 1.85 g
(87.5 %). 1H NMR (600 MHz): δ = 0.76 [t, J = 7.2 Hz, 6 H,
(CH2)2CH3], 0.92 [s, 6 H, C(CH3)2], 1.20 [s, 6 H, C(CH3)2], 1.41
(m, 2 H, CH2), 2.06 (m, 2 H, CH2), 2.11 [s, 6 H, OC(=O)CH3],
2.42 (m, 2 H, CH2), 2.70 (m, 2 H, CH2), 6.90 (t, J = 6.6 Hz, 2 H,
CH-Ph), 6.93 (d, J = 7.2 Hz, 1 H, CH-Ph), 7.05 (t, J = 7.2 Hz, 2
H, CH-Ph), 7.09 (t, J = 7.2 Hz, 2 H, CH-Ph), 7.28 (t, J = 8.4 Hz,
4 H, CH-Ph), 7.42 (d, J = 8.4 Hz, 2 H, CH-Ph), 8.06 (d, J = 7.8 Hz,
2 H, CH-Ph) ppm. 13C{1H} NMR (150 MHz): δ = 11.2 [s,
(CH2)2CH3], 20.8 [s, C(CH3)2], 21.4 [s, C(CH3)2], 24.5 [s, O-C(=O)-
CH3], 25.2 (s, CH2), 52.0 (s, CH2), 57.1 [s, C(CH3)3], 115.9, 121.02,
123.7, 123.9, 124.5, 128.9, 135.0 (CH-C6H5), 120.99, 130.8, 145.9,
154.6, 157.6 (one η1-Ph, two Cipso-C6H5, and two C=N), 180.4 [s,
O-C(=O)-CH3] ppm. C44H50N6O4Pd2 (939.75): calcd. C 56.24, H
5.36, N 8.94; found C 56.31, H 5.28, N 8.92.
[{[PhN=CA(CBMe2)(NB-η1-C6H4)CC=N(CH2)2CH3(CA–NB)(CB–
CC)]PdCl}2] (11): The procedure for the preparation of 11 was sim-
ilar to that used for 9 but with 4 (0.12 g, 0.13 mmol), 20 mL of
saturated NaCl(aq.) and 15 mL of acetone . A yellow solid was ob-
1
tained. Yield: 0.10 g (90.5%). H NMR (600 MHz): δ = 0.83 [s, 3
H, CH2CH3], 1.38 [d, J = 9 Hz, 6 H, C(CH3)2], 1.78 [m, 2 H,
(CH2)2CH3], 3.43 [m, 3 H, (CH2)2CH3], 6.87 (d, J = 8.4 Hz, 2 H,
CH-Ph), 7.05 (m, 2 H, CH-Ph), 7.25 (t, J = 7.8 Hz, 2 H, CH-Ph),
7.51 (t, J = 8.4 Hz, 1 H, CH-Ph), 7.90 (d, J = 7.8 Hz, 1 H, CH-
Ph) ppm. 13C{1H} NMR (150 MHz): δ = 11.1 [s, (CH2)2CH3], 21.4
[s, C(CH3)2], 25.5 [s, (CH2)2CH3], 52.9 [s, (CH2)2CH3], 57.0 [s,
C(CH3)2], 116.0, 120.9, 124.0, 124.5, 125.2, 128.9, 138.0 (CH-
C6H5), 120.5, 130.1, 145.7, 153.7, 158.5 (one η1-Ph, two Cipso-C6H5
and two C=N) ppm. C40H44Cl2N6Pd2 (892.56): calcd. C 53.83, H
4.97, N 9.42; found C 53.94, H 5.25, N 9.34. HRMS: m/z for
C40H44Cl2N6Pd2 (M+): calcd. 890.1074; found 890.1071.
[{[PhN=CA(CBMe2)(NB-η1-C6H4)CC=NPh(CA–NB)(CB–CC)]Pd-
(OAc)}2] (8): CH3CN (30 mL) was added to a flask containing
Pd(OAc)2 (0.45 g, 2 mmol) and 4 (0.61 g, 2 mmol) at room tem-
perature. After 7 h of stirring, the reaction mixture was filtered and
the filtrate was pumped to dryness to afford a pale-grey solid.
Yield: 0.49 g (98%). 1H NMR (600 MHz): δ = 0.72 [d, J = 19.8 Hz,
6 H, C(CH3)2], 1.31 [s, 3 H, O-C(=O)-CH3], 6.95 (d, J = 7.8 Hz, 2
H, CH-Ph), 7.04 (t, J = 7.2 Hz, 1 H, CH-Ph), 7.09 (br., 3 H, CH-
Ph), 7.16 (t, J = 7.8 Hz, 1 H, CH-Ph), 7.22 (m, 4 H, CH-Ph), 7.75
(d, J = 8.4 Hz, 1 H, CH-Ph), 8.26 (d, J = 7.8 Hz, 1 H, CH-Ph) ppm.
13C{1H} NMR (150 MHz): δ = 20.8, 20.0, 23.2 [one O-C(=O)-CH3,
two C(CH3)3], 57.9 (s, C(CH3)3), 116.0, 121.0, 124.0, 124.9, 125.5,
128.0, 128.9, 136.3 (CH-C6H5), 123.1, 125.5, 131.9, 142.3, 145.8,
154.9, 160.0 (one η1-Ph, two Cipso-C6H5 and two C=N), 180.1 [s,
O-C(=O)-CH3] ppm. C50H46N6O4Pd2 (1007.78): calcd. C 59.59, H
4.60, N 8.34; found C 59.45, H 4.06, N 8.20.
General Procedure for the Suzuki Reaction: The appropriate
amounts of catalyst, base (2.0 equiv.), boronic acid (1.5 equiv.) and
aryl halide (1.0 equiv.) were placed in a Schlenk tube under nitro-
gen. Solvent (2 mL) was added by syringe, and the reaction mixture
was stirred at room temperature or heated to the appropriate tem-
perature for the appropriate time.
General Procedure for the Heck-type Reaction: The appropriate
amounts of catalyst, base (1.5 equiv.) and aryl halide (1 equiv., sol-
ids) were placed in a Schlenk tube under nitrogen. Solvent (2 mL),
styrene (1.3 equiv.) and aryl halides (1 equiv., liquids) were added
by syringe, and the reaction mixture was heated to the appropriate
temperature for the appropriate time.
Crystal Structure Data: Crystals were grown from concentrated
hexane solution (2 and 4), CH2Cl2/hexane solution (for 5, 7 and 8)
or chloroform solution (for 9) and isolated by filtration. They were
sealed in thin-walled glass capillaries under a nitrogen atmosphere
and mounted on a Bruker AXS SMART 1000 diffractometer. The
absorption correction was based on the symmetry equivalent reflec-
tions using the SADABS program.[26] The space group determi-
nation was based on a check of the Laue symmetry and systematic
absences and was confirmed using the structure solution. The
structure was solved by direct methods using the SHELXTL pack-
age.[27] All non-H atoms were located from successive Fourier maps,
and hydrogen atoms were refined using a riding model. Anisotropic
thermal parameters were used for all non-H atoms, and fixed iso-
tropic parameters were used for H atoms. Some details of the data
collection and refinement are given in Table 3.
[[PhN=CA(CBMe2)(NB-η1-C6H4)CC=N(CH2)2OMe(CA–NB)(CB–
CC)}PdCl] (9): Acetone (15 mL) was added to a flask containing
5 (0.27 g, 0.28 mmol) and 20 mL of saturated NaCl(aq.) at room
temperature. After 2 h of stirring, the yellow suspension was fil-
tered and the residue was pumped to dryness to afford a yellow
solid. The crude product was washed with 20 mL of distilled water
to yield a yellow solid. Yield: 0.22 g (84.3%). 1H NMR (600 MHz):
δ = 1.49 [s, 6 H, C(CH3)2], 3.66 (t, J = 5.1 Hz, 2 H, CH2), 3.70 (t,
J = 5.1 Hz, 2 H, CH2), 3.78 (s, 3 H, OCH3), 6.93 (m, 3 H, CH-
Ph), 7.14 (m, 2 H, CH-Ph), 7.34 (t, J = 7.8 Hz, 2 H, CH-Ph), 8.02
(d, J = 7.8 Hz, 1 H, CH-Ph), 8.25 (br., 1 H, CH-Ph) ppm. 13C{1H}
NMR (150 MHz): δ = 20.9 [s, C(CH3)2], 48.4 (s, CH2), 57.0 [s,
C(CH3)2], 62.3 (s, OCH3), 74.3 (s, CH2), 117.1, 120.8, 124.3, 124.7,
125.4, 129.0, 141,4 (CH-C6H5), 118.9, 129.9, 145.4, 153.3, 157.9
(one η1-Ph, two Cipso-C6H5 and two C=N) ppm. C20H22ClN3OPd
(462.28): calcd. C 51.96, H 4.80, N 9.09; found C 51.92, H 4.83, N
8.60.
CCDC-678688 (for 2), -678689 (for 4), -678690 (for 5), -678691 (for
7), -678692 (for 8) and -678693 (for 9) contain the supplementary
3148
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 3142–3150

Palladacyclic Complexes as Catalysts in Cross-Coupling Reactions
Table 3. Summary of crystal data for compounds 2, 4, 5, 7, 8 and 9.
2
4
5·2CH2Cl2·H2O
7·0.5CH2Cl2
8·CH2Cl2
9
Formula
Fw
T [K]
Crystal system
C20H21N3O2 C23H21N3
C46H50Cl4N6O7Pd2 C89H100Cl2N12O8Pd4 C51H48Cl2N6O4Pd2 C20H22ClN3OPd
335.40
297(2)
triclinic
339.43
297(2)
triclinic
1153.52
297(2)
monoclinic
C2/c
1962.31
297(2)
1092.65
297(2)
462.26
297(2)
monoclinic
P21/c
triclinic
triclinic
¯
P1
¯
¯
¯
Space group
P1
P1
P1
a [Å]
b [Å]
c [Å]
α°
9.002(2)
9.664(2)
11.257(3)
82.840(5)
72.492(5)
75.453(5)
902.7(4)
2
9.1696(11)
11.3274(14)
11.4899(13)
60.765(2
76.296(2)
67.895(2)
962.8(2)
2
15.408(3)
20.769(5)
18.664(4)
90
113.175(4)
90
5491(2)
4
1.395
11.1482(9)
12.3221(11)
18.0280(15)
70.409(2)
72.549(2)
83.226(2)
2225.3(3)
1
11.461(3)
12.590(3)
18.745(4)
106.822(4)
103.947(5)
97.723(5)
2451.3(10)
2
11.1268(15)
15.317(2)
12.7024(17)
90
115.158(2)
90
1959.4(5)
4
1.567
β [°]
γ [°]
V [Å3]
Z
ρcalcd. [Mg/m3]
1.234
0.081
1.171
0.070
1.464
0.916
1.480
0.893
µ(Mo-Kα) [mm]–1
0.899
1.097
Reflections collected 5165
5551
235
0.0607
0.1594
1.015
15378
316
0.0419
0.1236
1.005
25290
527
0.0354
0.1293
13934
586
0.0406
0.0928
10892
235
0.0339
0.1030
1.019
No. of parameters
226
R1[a]
0.0628
0.1535
1.017
[a]
wR2
[b]
GoF
1.035
1.036
[a] R1 = [Σ(|Fo| – |Fc|]/Σ |Fo|]; wR2 = [Σw(Fo – Fc ) /Σw(Fo2)2]1/2; w = 0.10. [b] GoF = [Σw(Fo – Fc ) /(Nrflns – Nparams)]1/2
.
2
2 2
2
2 2
[17]
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Acknowledgments
Financial support from the National Science Council (grant
number NSC 95-2113-M-005-010-MY3) and the Ministry of Edu-
cation, Taiwan, ROC (under the ATU plan) is appreciated.
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Received: February 22, 2008
Published Online: June 10, 2008
3150
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Eur. J. Inorg. Chem. 2008, 3142–3150