Dichloropalladium complexes ligated by 4,5-bis(arylimino) pyrenylidenes: Synthesis, characterization, and catalytic behavior towards Heck-reaction

Article abstract of DOI:10.1016/j.jorganchem.2013.08.006

A series of 4,5-bis(arylimino)pyrenylidenylpalladium(II) chloride complexes (C1-C4) were synthesized and characterized by FT-IR and NMR spectroscopy, elemental analysis as well as by single crystal X-ray diffraction for the representative complexes C1 and

Full text of DOI:10.1016/j.jorganchem.2013.08.006

Journal of Organometallic Chemistry 751 (2014) 453e457
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Dichloropalladium complexes ligated by 4,5-bis(arylimino)
pyrenylidenes: Synthesis, characterization, and catalytic behavior
towards Heck-reaction
,
,
b
,
c,
Kuifeng Song a b, Shaoliang Kong b, Qingbin Liu a , Wen-Hua Sun , Carl Redshaw
*
*
**
a Institute of Chemistry and Chemical Engineering, Hebei Normal University, Shijiazhuang 050091, China
b Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing
100190, China
c Department of Chemistry, University of Hull, Hull HU6 7RX, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of 4,5-bis(arylimino)pyrenylidenylpalladium(II) chloride complexes (C1eC4) were synthesized
and characterized by FT-IR and NMR spectroscopy, elemental analysis as well as by single crystal X-ray
diffraction for the representative complexes C1 and C3, which revealed a square planar geometry at the
palladium center. All palladium complexes exhibited high activity for the Heck cross-coupling reaction,
which were effective when conducted in various solvents. Furthermore, the in-situ mixture of palladium
dichloride and the ligand (L1) provided an effective catalytic system for the Heck-reaction.
Ó 2013 Elsevier B.V. All rights reserved.
Received 30 May 2013
Received in revised form
2 August 2013
Accepted 5 August 2013
Keywords:
a
-Diimine
Palladium complex
Heck-reaction
1. Introduction
bidentate ligands such as diimine [30], dipyridine [31e36] and
hydrazine are useful [37]. Interestingly, reports on olefin polymer-
The arylation and vinylation of alkenes with aryl or vinyl halides,
known as the Heck reaction, was discovered independently by Heck
[1] and Mizoroki [2] in the early 1970s, and has subsequently
gained popularity in carbonecarbon formation in synthetic organic
syntheses promoted by palladium compounds [3e12]. Moreover,
palladium-mediated organic synthesis is also extended to the re-
actions of SonogashiraeHagihara [13,14] and SuzukieMiyaura [15e
18]. In order to improve the catalytic efficiency of the palladium
system, various complexes have been developed and investigations
into the electronic and steric influences exerted by the nature of the
substituents on the ligands employed have been reported [19e21].
Moreover, some palladium complex pre-catalysts could promote
the coupling reaction of less active haloarenes or alkenes [22e25].
These palladium complex pre-catalysts have often employed li-
gands derived from phosphine compounds [26e29], for which the
toxicity in the application is commonly a concern. Further explo-
rations into other potentially flexible (and efficient) ligands have
suggested that palladium complex pre-catalysts bearing N,N-
ization by N,N-bidentate palladium complexes have been published
[38e42], of which a few were also explored for their application in
the Heck reaction [43,44]. During our search for highly active pre-
catalysts of
a-diiminonickel complexes in ethylene polymeriza-
tion [45e51], a number of catalytic systems exhibited high activ-
ities and enhanced thermal stabilities [49e52]. In addition, the 1,2-
bis(arylimino)acenaphthylenylpalladium chlorides were found to
be highly active and thermally stable in the Heck reaction [52].
More recently, a series of 4,5-bis(arylimino)pyrenylidenes was
developed and successfully used as ligands for their nickel complex
pre-catalysts in ethylene polymerization [53]. To broaden the scope
of such compounds acting as ligands in catalysis, their palladium
complexes have been prepared and were found to be highly active
in promoting Heck coupling. Herein, the synthesis and character-
ization of the title palladium complexes and their catalytic behavior
in the Heck reaction are reported.
2. Results and discussion
2.1. Synthesis and characterization of ligands and complexes
* Corresponding authors. Tel.: þ86 10 62557955; fax: þ86 10 62618239.
** Corresponding author.
E-mail addresses: whsun@iccas.ac.cn (W.-H. Sun), c.redshaw@hull.ac.uk
(C. Redshaw).
The 4,5-bis(arylimino)pyrenylidenes (L1eL4) were prepared
according to the reported method [53]. The a-Diiminopalladium (II)
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.08.006

454
K. Song et al. / Journal of Organometallic Chemistry 751 (2014) 453e457
chlorides (C1eC4) were obtained by the reaction of the corre-
sponding ligands with (CH3CN)2PdCl2 in dichloromethane at room
temperature (Scheme 1). All complexes tended to precipitate from
the reaction solution, and optimized yields were obtained by
adding excessive amount of Et2O to the reaction solution. The
elemental analysis data confirmed their composition as LPdCl2, and
the complexes were further identified by FT-IR and NMR spectro-
scopic measurements.
The stoichiometric reaction of (CH3CN)2PdCl2 with the
a-dii-
mino ligands (L1eL4) in dichloromethane afforded the corre-
sponding palladium chloride complexes (C1eC4) in reasonable
isolated yields. Moreover, these complexes were characterized by
elemental and spectroscopic analysis. Due to the efficient coordi-
nation of Nimino to Pd, the absorption of the vC]N vibration became
quite weak in the IR spectra of the palladium complexes, which is
consistent with the observation of the infrared inactive C]N vi-
bration in the palladium complexes [54]. The 13C NMR peaks for the
C]N groups in the palladium complexes were shifted to lower
Fig. 1. ORTEP drawing of C1. Thermal ellipsoids are shown at the 30% probability level.
Hydrogen atoms have been omitted for clarity.
field, for example d 167.1 ppm for C3 vs 159.1 ppm for L3, and were
indicative of the strong coordination between the Nimino atom and
the Pd center [55]. To confirm the structures of the palladium
complexes, single crystals of complexes C1 and C3 were obtained
and the molecular structures were determined by single crystal X-
ray diffraction.
exhibited poor catalytic activities in the range 103 g(PE)$molꢁ1(Pd)$
h
ratio at 2000. Therefore, trials of their potential in Heck coupling
became the focus of our studies here.
ꢁ1, with the assistance of MAO (co-catalyst) and with an Al/Pd
The complex C1 was explored for the Heck reaction of bromo-
benzene with styrene to ascertain the optimum conditions for
producing 1,2-diphenylethene. Besides the palladium complex pre-
catalyst, in principle, the catalytic behavior can also be significantly
affected by the inorganic base and organic solvent used. The trial
conditions were fixed at a slight excess (1.2 equivalent) of styrene
and 1.1 equivalents of inorganic base to bromobenzene with a
catalytic amount of C1 ([Pd]/[bromobenzene] ¼ 4 ꢂ 10ꢁ5); the
conversion of bromobenzene was monitored and results are tabu-
lated in Table 2. According to our previous experience [52], the
N,N’-dimethylacetamide (DMA) is the preferred solvent and this
was utilized in the presence of different inorganic bases (entries 1e
9, Table 2). As shown by entries 1 to 5 with the base as Na2CO3, it is
necessary to activate the catalytic system by elevating the reaction
temperature. Trace amounts of bromobenzene were converted over
12 h at 120 ꢀC (entry 1, Table 2); meanwhile, at 150 ꢀC, 70% of
bromobenzene was converted over 3 h (entry 2, Table 2), and more
bromobenzene was converted on further prolonging the reaction
time (entries 3 and 4, Table 2); more than 99% of bromobenzene
was converted over 12 h at 150 ꢀC (entry 5, Table 2) without
2.2. Crystal and molecular structures
Single crystals of the representative complexes C1 and C3 were
obtained by slow diffusion of diethyl ether into dichloromethane
solutions at ambient temperature. The molecular structures of each
are shown in Figs. 1 and 2, respectively, with selected bond lengths
and angles tabulated in Table 1. As shown in Figs. 1 and 2, the
complexes C1 and C3 possess similar structures, that is, with a
square planar geometry at the palladium center comprised of two
nitrogen atoms (of the chelate) and two chloride atoms. For the
complexes C1 and C3, the double bonding features are illustrated
ꢀ
ꢀ
ꢀ
by N1eC1 1.301(5) A and N2eC14 1.310(5) A in C1 and 1.306(6) A
ꢀ
and 1.308(6) A in C3, whilst the single bonds for N1eC17 and N2e
ꢀ
ꢀ
ꢀ
C23 are 1.431(5) A and 1.448(5) A in C1 and 1.439(6) A and
ꢀ
1.433(6) A in C3. The dihedral angles formed by the C17eC18eC22
and C1eN1ePd1 are 89.3ꢀ in C1 and 80.3ꢀ in C3. In addition, the
dihedral angles formed by the two imino-phenyl rings connected to
the nitrogen atoms are 24.8ꢀ in C1 and 18.6ꢀ in C3, respectively.
Compared to the crystal structure of L3 [53], there are obvious
changes of the dihedral angles involving the two imino-phenyl
rings at 72.67ꢀ in L3 and 18.6ꢀ in C3, the difference being attrib-
uted to more efficient coordination to the palladium center in C3.
2.3. Catalytic behavior
With regard to the use of these palladium complexes as pre-
catalysts in ethylene polymerization, the complexes C1eC4
(CH3CN)2PdCl2
R1
R1
R1
R1
CH2Cl2, r.t.
N
N
N
N
Pd
Cl
Cl
R2
R1
L1 − L4
R1
R2
R2
4
R1
R1
R2
1
2
3
C1 − C4
R1
R2
Me Et Me Et
Me Me
H
H
Fig. 2. ORTEP drawing of C3. Thermal ellipsoids are shown at the 30% probability level.
Scheme 1. Synthetic procedure for the palladium complexes (C1eC4).
Hydrogen atoms have been omitted for clarity.

K. Song et al. / Journal of Organometallic Chemistry 751 (2014) 453e457
455
Table 1
Table 3
Heck reaction of bromobenzene and styrene by C1eC4.a
ꢀ
ꢀ
Selected bond lengths (A) and angles ( ) for complexes C1 and C3.
4×
10-3 mol% [Pd]
Br
C1
C3
1.1 mol% Na2CO3
DMA
ꢀ
+
Bond lengths (A)
Pd(1)eN(1)
Pd(1)eN(2)
Pd(1)eCl(1)
Pd(1)eCl(2)
N(1)eC(1)
N(1)eC(17)
N(2)eC(14)
N(2)eC(23)
Bond angles (ꢀ)
N(1)ePd(1)eN(2)
N(1)ePd(1)eCl(1)
N(2)ePd(1)eCl(1)
N(1)ePd(1)eCl(2)
N(2)ePd(1)eCl(2)
Cl(1)ePd(1)eCl(2)
2.024(3)
2.003(3)
2.2753(12)
2.2859(12)
1.301(5)
1.431(5)
1.310(5)
1.448(5)
2.018(4)
2.023(4)
2.2910(13)
2.2866(13)
1.306(6)
1.439(6)
1.308(6)
c
Entry
Cat.
Mol % Pd
Conversion (%)b
TOF (hꢁ1
)
1
2
3
4
5
6
7
C1
C2
C3
C4
0.004
0.004
0.004
0.004
0.002
0.004
0.004
ꢃ99
ꢃ99
ꢃ99
ꢃ99
89
2100
2100
2100
2100
1850
905
1.433(6)
78.20(13)
96.56(10)
174.07(10)
174.28(10)
96.76(9)
78.18(16)
96.79(12)
172.92(12)
173.05(12)
96.54(12)
88.86(5)
C1
(CH3CN)2PdCl2
(CH3CN)2PdCl2 þ L1
42
81
1700
a
Reaction conditions: 2.0 mmol bromobenzene, 2.4 mmol styrene, 2.2 mmol
Na2CO3, 40 mL DMA, 150 ꢀC, 12 h.
88.60(4)
b
Determined by GC.
TOF: mol bromobenzene/mol Pd $ h.
c
observing any remaining bromobenzene. With such observations,
it is arguable whether the palladium complex remains the same at
150 ꢀC; the palladium complex (C1) in N,N’-dimethylacetamide
(DMA) solution was refluxed for 12 h at 150 ꢀC and was recovered in
95% yield after being re-crystallization, confirming the unchanged
nature of the palladium complex under the reaction conditions
employed herein. No other better result was observed for the cat-
alytic system when other bases such as NaOAc (entry 6, Table 2),
K2CO3 (entry 7, Table 2) or NaOH (entry 8, Table 2) were employed.
In addition, the solvent DMA was the most effective solvent in
comparison to others including N,N’-dimethylformamide (DMF)
(entry 9, Table 2), tetrahydrofuran (THF) (entry 10, Table 2), CH3CN
(entry 11, Table 2) or toluene (entry 12, Table 2).
The optimized conditions observed for complex C1, 1.2 equiva-
lent of styrene and 1.1 equivalent of Na2CO3 to bromobenzene with
the [Pd]/[bromobenzene] at 4 ꢂ 10ꢁ5 at 150 ꢀC for 12 h in DMA,
were then employed for all palladium complexes in the Heck
coupling reaction (Table 3); quantitative conversion was achieved
(entry 1e4, Table 3). Thus, these ligands can be said to provide
suitable coordination about the palladium center to efficiently
promote the Heck reaction. Even on reducing the loading of com-
plex C1 to half, the conversion of bromobenzene achieved was still
as high as 89% (entry 5, Table 3) over 12 h and 98% over 24 h.
Moreover, when the substances and Na2CO3 were mixed in DMA,
and then the requisite amounts of (CH3CN)2PdCl2 (entry 6, Table 3)
and the equivalent amount of ligand L1 (entry 7, Table 3) were
individually added to the solution, the conversion of bromo-
benzene observed was 42% (entry 6, Table 3) without the ligand
versus 81% (entry 7, Table 3) on adding ligand over 12 h. In addition,
a small amount of suspended particles were also observed, possibly
due to a side reaction of (CH3CN)2PdCl2 and Na2CO3. Such studies
are an indication of the stability of the diiminopalladium (II)
chloride (e.g. C1) in the presence of Na2CO3 in the DMA solution.
Given its catalytic efficiency in the Heck reaction, the complex
C1 was studied further in the coupling of a number of aryl halides
and olefins. The results are summarized in Table 4. In the Heck
reaction, the effect of varying the aryl bromides was investigated
using an olefin as the substrate under the optimized reaction
conditions (entries 1e8, Table 4). From Table 4, it could be observed
that the coupling reactions achieved good activities. However, the
aryl bromides showed relatively lower activities than did bromo-
benzene, which is consistent with previous literature observations
[56] reflecting the bulk of the substituents. In addition, the position
of the substituents also influenced the results due to electronic
effects, such as entry 2e8 in Table 4. Moreover, the lower activities
observed for 2-bromothiophene, 2-bromobenzenamine and 4-
bromoaniline (entries 4, 7 and 8, Table 4) were tentatively attrib-
uted to the potential coordination between the functional groups
(amine and sulfur atom) and the palladium species. All products
were isolated and confirmed by 1H and 13C NMR spectroscopy and
by comparison with literature data [57,58].
Table 2
Optimization of bromobenzene and styrene using complex C1.a
Br
4×
10-3 mol% C1
1.1 mol% base
Solvent
+
3. Conclusions
c
Entry Base
Solvent Temp. (ꢀC) Time (h) Conversion (%)b TOF (hꢁ1
)
A series of palladium complexes have been synthesized and
characterized, including by single-crystal X-ray analysis; the
palladium atom is coordinated by two nitrogen atoms and two
chloride atoms. All complexes showed high catalytic activity for
Heck coupling between aryl bromide and olefins, exhibiting high
thermal stability.
1
2
3
4
5
6
7
8
Na2CO3 DMA
Na2CO3 DMA
Na2CO3 DMA
Na2CO3 DMA
Na2CO3 DMA
NaOAc DMA
120
150
150
150
150
150
150
150
150
60
12
3
6
Trace
70
85
e
5800
3500
2600
2100
1100
1600
e
9
94
12
12
12
12
12
12
12
12
ꢃ99
51
K2CO3
KOH
DMA
DMA
75
Trace
90
Trace
Trace
Trace
9
Na2CO3 DMF
Na2CO3 THF
Na2CO3 CH3CN
1900
e
4. Experimental section
10
11
12
80
e
4.1. General procedure and materials
Na2CO3 Toluene 110
e
a
Reaction conditions: 2.0 mmol bromobenzene, 2.4 mmol styrene, 2.2 mmol
base, 4.0 mL solvent.
All manipulations of moisture-sensitive compounds were car-
ried out under an atmosphere of nitrogen using standard Schlenk
techniques. All organic compounds used as ligands were prepared
b
Determined by GC.
c
TOF: mol bromobenzene/mol Pd $ h.

456
K. Song et al. / Journal of Organometallic Chemistry 751 (2014) 453e457
Table 4
isolated by re-crystallization as a red solid (0.10 g, 52.7%). Mp:
>250 ꢀC. FT-IR (KBr, cmꢁ1): 3055 (w), 2920 (s), 2852 (s), 1728 (s),
1621 (s), 1579 (m), 1356 (s), 1306 (s), 1262 (s), 1707 (s), 836 (s), 762
Heck reaction of aryl bromides and styrene using complex C1.a
4×
10-3 mol% [Pd]
(s), 705 (vs). 1H NMR (400 MHz, CDCl3, TMS):
d
8.13 (d, J ¼ 8.0, 2H,
1.1 mol% Na2CO3
DMA
Ar
+
ArBr
Ph
Pyrene H), 7.84 (s, 2H, Pyrene H), 7.45 (d, J ¼ 8.0, 2H, Pyrene H), 7.33-
7.27 (m, 6H, Pyrene H, Ph H), 7.25e7.23 (m, 2H, Ph H), 2.36 (s, 12H,
Ph
PheCH3). 13C NMR (100 MHz, CDCl3, TMS):
d 166.8, 147.4, 136.5,
132.6, 130.4, 129.5, 128.9, 128.4, 128.2, 128.1, 127.1, 124.8, 18.7. Anal.
Calcd for C32H26Cl2N2Pd: C, 62.40; H, 4.26; N, 4.55. Found: C, 62.15;
H, 4.43; N, 4.22.
c
Entry
ArBr
Conversion (%)b
TOF (hꢁ1
)
Complex C2: Using the same procedure as for the synthesis of
C1, the red powder C2 was produced in 17.2% yield. Mp: >250 ꢀC.
FT-IR (KBr, cmꢁ1): 3058 (w), 2964 (s), 2869 (s), 2361 (s), 1623 (s),
1583 (m), 1460 (s), 1356 (s), 1302 (s), 1223 (s), 833 (s), 754 (s), 705
1
2
99
86
2100
Br
1800
H3C
Br
(vs). 1H NMR (400 MHz, CDCl3, TMS):
d
8.13 (d, J ¼ 8.00, 2H, Pyrene
H), 7.86 (s, 2H, Pyrene H), 7.47e7.43 (m, 4H, Pyrene H), 7.37e7.30
(m, 6H, Ph H), 3.12e3.07 (m, 4H, PheCH2e), 2.59e2.54 (m, 4H, Phe
CH2e), 1.28 (t, J ¼ 7.6, 12H, PheCH3). 13C NMR (100 MHz, CDCl3,
Br
3
4
75
58
1600
1200
TMS):
d 166.9, 146.6, 136.1, 133.1, 132.5, 131.1, 128.7, 128.2, 128.0,
CH3
127.3, 126.9, 125.1, 24.8, 13.1. Anal. Calcd for C36H34Cl2N2Pd: C,
64.34; H, 5.10; N, 4.17. Found: C, 64.18; H, 5.28; N, 4.04.
Complex C3: Using the same procedure as for the synthesis of C1,
the red powder C3 was produced in 54.3% yield. Mp: >250 ꢀC. FT-IR
(KBr, cmꢁ1): 3056 (w), 2963 (s), 2902 (m), 2371 (s), 1971 (m), 1624
(s),1617 (s),1575 (s),1472 (vs),1302 (vs),1033 (s), 838 (vs), 709 (vs).1H
S
Br
5
6
70
73
1500
1500
MeO
Br
NMR (400 MHz, CDCl3, TMS):
d
8.14 (d, J ¼ 6.8, 2H, Pyrene H), 7.86 (s,
2H, Pyrene H), 7.54 (d, J ¼ 7.2, 2H, Pyrene H), 7.08 (s, 4H, Pyrene H, Ph
H), 2.33 (s, 6H, PheCH3), 2.23 (s, 12H, PheCH3). 13C NMR (100 MHz,
CDCl3, TMS): d 167.1, 145.4, 138.1, 136.0, 132.5, 130.4, 130.3, 128.2, 128.1,
127.8, 127.2, 125.0, 21.5, 18.7. Anal. Calcd for C34H30Cl2N2Pd: C, 63.42;
H, 4.70; N, 4.35. Found: C, 63.35; H, 4.77; N, 4.13.
MeO
H2N
Br
Complex C4: Using the same procedure as for the synthesis of
C1, the red powder C4 was produced in 45.1% yield. Mp: >250 ꢀC.
FT-IR (KBr, cmꢁ1): 3058 (w), 2962 (s), 2870 (s), 2361 (s), 2336 (s),
1622 (m), 1600 (s), 1507 (s), 1452 (s), 1359 (s), 1304 (vs), 835 (s), 705
7
57
47
1200
1000
Br
Br
(vs). 1H NMR (400 MHz, CDCl3, TMS):
d
8.13 (d, J ¼ 8.0, 2H, Pyrene
8
H), 7.85 (s, 2H, Pyrene H), 7.50 (d, J ¼ 8.4, 2H, Pyrene H), 7.34 (t,
J ¼ 7.6, 2H, Pyrene H), 7.13 (s, 4H, Ph H), 3.06e2.99 (m, 4H, PheCH2e
), 2.56e2.50 (m, 4H, PheCH2e), 2.46 (s, 6H, PheCH3), 1.24 (t, J ¼ 7.6,
NH2
a
Reaction conditions: 2.0 mmol ArBr, 2.4 mmol styrene, 2.2 mmol Na2CO3, 4.0 mL
DMA, 150 ꢀC, 12 h.
12H, PheCH3). 13C NMR (100 MHz, CDCl3, TMS):
d 167.2, 144.4,
b
Determined by GC.
138.2, 135.8, 132.8, 132.5, 131.1, 128.1, 127.9, 127.7, 127.9, 125.2, 24.8,
21.9, 13.2. Anal. Calcd for C38H38Cl2N2Pd: C, 65.20; H, 5.47; N, 4.00.
Found: C, 64.96; H, 5.63; N, 3.74.
c
TOF: mol ArBr/mol Pd$h.
according to our previous procedure [53]. Melting points were
determined using a digital electrothermal apparatus without cali-
bration. NMR spectra were recorded on a Bruker DMX 400 MHz
instrument at ambient temperature using TMS as an internal
standard;
spectra were obtained on a PerkineElmer FT-IR 2000 spectropho-
tometer by using the KBr disc in the range of 4000e400 cmꢁ1
4.3. Heck reaction
General procedure for the Heck reaction of bromobenzene with
styrene in the presence of palladium complex, as a typical proce-
dure, the example uses C1 as in entry 3 of Table 2. A 50 ml oven-
dried Schlenk flask was charged under nitrogen with 2.0 mmol
d values are given in ppm and J values in Hz. The IR
.
Elemental analysis was carried out using a Flash EA 1112 micro-
analyzer. Conversions were determined by CP-3800 GC.
bromobenzene (210
ml, 313 mg), 2.4 mmol styrene (280 ml, 254 mg),
anhydrous 2.2 mmol Na2CO3 (233 mg) and 4.0 ml DMA. A 100
ml
solution of 4 mmol complex C1 in 5 ml DMA was added via syringe
to the above solution, and then the reactor was sealed and placed in
a 150 ꢀC oil bath, and the mixture was stirred for 12 h. After cooling
to room temperature, the mixture was diluted with EtOAc and
water. The organic layer was washed with brine, dried over Na2SO4,
and concentrated under reduced pressure. The residue was purified
by column chromatography on silica gel using petroleum ether.
4.2. Syntheses of palladium complexes (C1eC4)
The complexes (C1eC4) were prepared by the reaction of
(CH3CN)2PdCl2 with the corresponding ligands (L1eL4) in
dichloromethane according to the literature method [52,59].
Herein, only the synthesis of palladium complex C1 is described:
the ligand 4,5-bis(2,6-dimethylphenylimino)pyrenylidene (L1)
(0.34 mmol, 0.15 g) and (CH3CN)2PdCl2 (0.34 mmol, 0.09 g) were
added to a flame-dried Schlenk flask tube, then 10 ml dichloro-
methane was subsequently added with rapid stirring at room
temperature for 12 h. The solvent was removed in-vacuo and the
residual solid was washed with Et2O several times. Finally, C1 was
4.4. X-ray crystallographic studies
Single crystals of complexes C1 and C3 suitable for X-ray
diffraction were grown by slow diffusion of diethyl ether into
dichloromethane solutions at room temperature. X-ray studies

K. Song et al. / Journal of Organometallic Chemistry 751 (2014) 453e457
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Crystal data and structure refinement for C1 and C3.
C1
C3
Empirical formula
Cryst color
Fw
C32H26Cl2N2Pd
Black
615.85
C34H30Cl2N2Pd
Black
643.90
173(2)
0.71073
Monoclinic
P2(1)/c
10.874(2)
12.136(2)
22.022(4)
90
91.48(3)
90
2905.4(10)
4
T (K)
Wavelength (A)
173(2)
0.71073
ꢀ
Cryst syst
Monoclinic
P2(1)/n
13.232(3)
11.569(2)
19.224(4)
90
92.42(3)
90
2940.4(10)
4
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Space group
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
a
b
g
(ꢀ)
(ꢀ)
(ꢀ)
3
ꢀ
V (A )
}
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H. Fischer, Angew. Chem. Int. Ed. Engl. 34 (1995) 1844e1848.
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1454.
Dcalcd (mg mꢁ3
)
1.391
0.835
1.472
0.849
1312
m
(mmꢁ1
)
F(000)
Cryst size (mm)
range (deg) limiting indices
1248
0.46 ꢂ 0.25 ꢂ 0.11
1.83e27.49
ꢁ17 ꢄ h ꢄ 16
ꢁ15 ꢄ k ꢄ 14
ꢁ24 ꢄ l ꢄ 24
21,007
0.26 ꢂ 0.16 ꢂ 0.15
1.92ꢁ27.50
ꢁ12 ꢄ h ꢄ 14
ꢁ15 ꢄ k ꢄ 15
ꢁ28 ꢄ l ꢄ 25
20,161
6633(0.0566)
99.3 (
1.056
q
No. of rflns collected
No. unique rflns [R(int)]
6689(0.0450)
Completeness to
q
(%)
99.2 (
1.052
q
¼ 27.49)
q
¼ 27.50)
Goodness of fit on F2
Final R indices [I > 2
R indices (all data)
s
(I)]
R1 ¼ 0.0546
R1 ¼ 0.0608
wR2 ¼ 0.1556
R1 ¼ 0.0606
wR2 ¼ 0.1867
R1 ¼ 0.0706
ꢀꢁ3
Largest diff peak and hole (e A
)
wR2 ¼ 0.1693
0.852 and ꢁ0.703
wR2 ¼ 0.2047
0.828 and ꢁ0.932
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were carried out on a Rigaku Saturn724 þ CCD with graphite-
ꢀ
monochromatic Mo-K
a
radiation (
l
¼ 0.71073 A) at 173(2) K; cell
parameters were obtained by global refinement of the positions of
all collected reflections. Intensities were corrected for Lorentz and
polarization effects and empirical absorption. The structures were
solved by direct methods and refined by full-matrix least squares
on F2. All hydrogen atoms were placed in calculated positions.
Structure solution and refinement were performed by using the
SHELXL-97 package [60]. Details of the X-ray structure de-
terminations and refinements are provided in Table 5.
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Acknowledgments
This work is supported by NSFC No. 20904059. The RSC is
thanked for the awarded of a travel grant (to CR)
Appendix A. Supplementary material
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(2013) 9166e9175.
CCDC 934350e934351 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
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