Palladium(II) complexes containing N,N′-bidentate N-(pyridin-2-ylmethyl)aniline and its derivatives: Synthesis, structural characterisation, and methyl methacrylate polymerisation

Article abstract of DOI:10.1016/j.poly.2014.04.015

The reaction of [Pd(CH₃CN)₂Cl₂] with N-(pyridin-2-ylmethyl)aniline (L₁) and its derivatives (L ₂-L₆) in ethanol yields [(NN′)PdCl₂] complexes, namely [L_nPdCl₂] (L_n = L ₁-L₆). The X-ray crystal structure of Pd(II) complexes revealed that the palladium atom in [L_nPdCl₂] (L _n = L₁-L₆) showed a square plane geometry involving two nitrogen atoms of NN′-bidentate and two chlorido ligands. Complex [L₄PdCl₂] containing 2,4,6-trimethyl-N-(pyridin-2- ylmethyl)aniline (L₄) showed the highest catalytic activity for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) with an activity of 1.41 × 10⁵ g PMMA/mol Pd·h at 60 °C and poly(methyl methacrylate) (PMMA) syndiotacticity (characterised using ¹H NMR spectroscopy) of ca. 0.70.

Full text of DOI:10.1016/j.poly.2014.04.015

Polyhedron 77 (2014) 66–74
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Palladium(II) complexes containing N,N0-bidentate
N-(pyridin-2-ylmethyl)aniline and its derivatives: Synthesis,
structural characterisation, and methyl methacrylate polymerisation
Sunghoon Kim a, Dongil Kim a, Ha-Jin Lee b,c, Hyosun Lee a,
⇑
a Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu-city 702-701, Republic of Korea
b Jeonju Center, Korea Basic Science Institute (KBSI), 634-18 Keumam-dong, Dukjin-gu, Jeonju-city 561-180, Republic of Korea
c Department of Chemistry, Chonbuk National University, Dukjin-gu, Jeonju-city 561-756, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction of [Pd(CH3CN)2Cl2] with N-(pyridin-2-ylmethyl)aniline (L1) and its derivatives (L2–L6) in
ethanol yields [(NN0)PdCl2] complexes, namely [LnPdCl2] (Ln = L1–L6). The X-ray crystal structure of Pd(II)
complexes revealed that the palladium atom in [LnPdCl2] (Ln = L1–L6) showed a square plane geometry
involving two nitrogen atoms of NN0-bidentate and two chlorido ligands. Complex [L4PdCl2] containing
2,4,6-trimethyl-N-(pyridin-2-ylmethyl)aniline (L4) showed the highest catalytic activity for the polymer-
isation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) with an
activity of 1.41 ꢀ 105 g PMMA/mol Pdꢁh at 60 °C and poly(methyl methacrylate) (PMMA) syndiotacticity
(characterised using 1H NMR spectroscopy) of ca. 0.70.
Received 5 February 2014
Accepted 7 April 2014
Available online 18 April 2014
Keywords:
N-(pyridin-2-ylmethyl)aniline
N,N0-bidentate ligand
Palladium(II) complex
MMA polymerization
Syndiotacticity
Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction
[14,16,23–25,41,42,54–58], biological applications [26–28,40,59],
and olefin polymerisation [15,29,38,39].
Transition metal complexes containing N,N0-bidentate ligands
with pyridylmethylamines are common and diverse due to the
easy synthesis of ligands and their versatile modification through
the introduction of substituents on the amine residue and a pyridyl
unit [1–16]. Several structural variations in pyridylmethylamines
and their complexes have been reported, and their steric and elec-
tronic properties vary because the polydentate characteristics play
a role during catalysis [17–29]. These variations result in abundant
pyridylmethylamines and analogues of transition metal complexes
with specific chemical applications. Specifically, structural varia-
tions are observed in group 10 (Ni, Pd, and Pt) with pyridylmethyl-
amines and their derivatives. For example, Ni complexes exist as
tetrahedral to octahedral monomers or dimers with two ligand
units coordinated to Ni, achieving a five-coordinated or six-coordi-
nated structure [30–38]. In contrast, palladium and platinum
complexes mainly exist in a monomeric square-planar geometry
[39–60]. The majority of transition metal complexes containing
these ligands have been applied for synthesis, structural analysis,
and spectroscopy [1–11,17–22,30–37,43–53,60], used for elec-
tronic materials [12,13], catalysts for organic transformation
Despite abundant previous reports on transition metal com-
plexes with pyridylmethylamines and their derivatives, little is
known regarding Pd(II) complexes with N,N0-bidentate
pyridylmethylamines as catalysts for methyl methacrylate (MMA)
polymerisation [15]. On the other hand, poly(methylmethacrylate)
(PMMA) is a universal polymer with optical applications. A higher
glass transition temperature (Tg) typically represents higher optical
quality and syndiotacticity content of PMMA. The Tg of isotactic
PMMA, which is produced by radical commercial processes, is
around 65 °C. Thus, studies on non-radical-mediated polymerisa-
tion of MMA have been performed, and some transition metal
complexes have been successfully applied [61–69]. Regarding
co-ordination polymerisation of MMA mediated by transition metal
complexes, previous studies explored Pd(II) and Pt(II) complexes
with ligands bispyridylamine and iminopyridine as catalysts for
MMA polymerisation [70,71]. Thus, we report the preparation,
X-ray crystal structures, and MMA polymerisation of N,N0-bidentate
pyridylmethylaniline
ligands,
N-(pyridin-2-ylmethyl)aniline
(L1) [39], 4-methyl-N-(pyridin-2-ylmethyl)aniline (L2) [16,43,46],
,5-dimethyl-N-(pyridin-2-ylmethyl)aniline (L3), 2,4,6-trimethyl
-N-(pyridin-2-ylmethyl)aniline (L4), 2,6-diethyl-N-(pyridin-2-
ylmethyl)aniline (L5), 4-fluoro-N-(pyridin-2-ylmethyl)aniline (L6),
and their Pd(II) complexes.
⇑
Corresponding author. Tel.: +82 53 950 5337; fax: +82 53 950 6330.
E-mail address: hyosunlee@knu.ac.kr (H. Lee).
http://dx.doi.org/10.1016/j.poly.2014.04.015
0277-5387/Ó 2014 Elsevier Ltd. All rights reserved.

S. Kim et al. / Polyhedron 77 (2014) 66–74
67
C, 79.61; H, 8.016; N, 12.38. Found: C, 79.21; H, 8.019; N, 12.22%.
1H NMR (CDCl3, 400 MHz): d 8.51 (d, 1H, J = 7.6 Hz, –NC5H4–),
7.78 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.69 (d, 1H, J = 7.7 Hz, –NC5H4–),
7.54 (d, 1H, J = 7.7 Hz, –NC5H4–), 7.03 (s, 2H, –(CH3)3C6 H2–), 4.51
(s, 1H, –NH(CH3)3C6H3–), 3.94 (s, 2H, –CH2NC5H4–), 1.94 (s, 6H, o-
(CH3)3C6H2–), 1.72 (s, 3H, p-(CH3)3C6H2–). 13C NMR (CDCl3,
100 MHz): d 158.87 (s, 1C, ipso-NC5H4–), 156.23 (s, 1C, –NC5H4–),
150.55 (s, 1C, ipso-(CH3)3C6H2–), 133.89 (s, 1C, –NC5H4–), 132.86
(s, 1C, p-(CH3)3C6H2–), 130.86 (s, 2C, m-(CH3)3C6H2–), 129.70
(s, 2C, o-(CH3)3C6H2–), 130.57 (s, 1C, –NC5H4–), 128.44 (s,
1C, –NC5H4–), 42.86 (s, 1C, –CH2NC5H4–), 23.00 (s, 1C, p-(CH3)3C6
H2–), 21.81 (s, 3C, –(CH3)3C5H2–). IR (liquid neat; cmꢂ1): 3362
(w), 3309 (s), 3007 (s), 2917 (w), 2858 (s), 2732 (s), 1632 (s),
1589 (s), 1481 (s), 1436 (s), 1381 (s), 1304 (s), 1226 (s), 1150 (s),
1093 (s), 1003 (s), 851 (s), 746 (s), 607 (s), 566 (s).
2. Experimental
2.1. Physical measurement
PdCl2, 2-pyridinecarboxaldehyde, 3,5-dimethylaniline, 2,4,6-tri-
methylaniline, 2,6-diethylaniline, 4-fluoroaniline, magnesium sul-
fate, methyl methacrylate (MMA) were purchased from Aldrich
and anhydrous solvents such as CH3CN, C2H5OH, DMF, diethyl
ether, dichloromethane were purchased from Merck and used
without further purification. Modified methylaluminoxane
(MMAO) was purchased from Tosoh Finechem corporation as
6.9% weight aluminum of a toluene solution. Elemental analyses
(C, H, N) of complexes were carried out on an elemental analyzer
(EA 1108; Carlo-Erba, Milan, Italy). 1H NMR (operating at
400 MHz) and 13C NMR (operating at 100 MHz) spectra were
recorded on a Bruker Advance Digital 400 NMR spectrometer;
chemical shifts were recorded in ppm units (d) relative to SiMe4
as the internal standard. Melting point was measured by electro-
thermal IA 9100 apparatus. Infrared (IR) spectra were recorded
on Bruker FT/IR-Alpha and the data are reported in reciprocal cen-
timeters. The molecular weight and molecular weight distribution
of the poly(methylmethacrylate) (PMMA) were carried out using
gel permeation chromatography (GPC) (CHCl3, Alliance e2695;
Waters Corp., Milford, MA). Glass transition temperature (Tg) was
determined by differential scanning calorimetry (DSC, Q2000; TA
Instruments, New Castle, DE).
2.2.3. 2,6-Diethyl-N-(pyridin-2-ylmethyl)aniline (L5)
L5 [72]was prepared by analogous method as described for L1
except utilizing 2,6-diethylaniline (3.29 mL, 0.0200 mol) and 2-
pyridinecarboxaldehyde (1.90 mL, 0.0200 mol). The product was
obtained as light red oil (3.55 g, 73.9%). Anal. Calc. for C16H20N2:
C, 79.96; H, 8.387; N, 11.66. Found: C, 79.39; H, 8.194; N, 11.72%.
1H NMR (CDCl3, 400 MHz): d 8.49 (d, 1H, J = 7.6 Hz, –NC5H4–),
8.17 (d, 1H, J = 7.8 Hz, –NC5H4–), 8.13 (d, 1H, J = 7.8 Hz, –NC5H4–),
7.82 (s, 1H, d, 1H, J = 7.8 Hz, –NC5H4–), 6.58 (m, 3H, –(CH2CH3)2C6-
H3–), 4.94 (s, 2H, –CH2NC5H4–), 4.64 (s, 1H, –NH(CH2CH3)2C6H3–),
1.94 (m, 4H, –(CH2CH3)2C6H3–), 1.72 (t, 6H, J = 11 Hz, –(CH2CH3)2
C6H3–). 13C NMR (CDCl3, 100 MHz): d 159.12 (s, 1C, ipso-NC5H4-),
155.33 (s, 1C, –NC5H4–), 152.55 (s, 1C, ipso-(CH2CH3)2C6H3–),
138.89 (s, 1C, –NC5H4–), 137.86 (s, 2C, o-(CH2CH3)2C6H3–),
136.86 (s, 2C, m-(CH2CH3)2C6H3–), 132.84 (s, 1C, –NC5H4–),
131.74 (s, 1C, –NC5H4–), 128.44 (s, 1C, p-(CH2CH3)2C6H3–), 52.86
(s, 1C, –CH2NC5H4–), 23.00 (s, 2C, –(CH2CH3)2C6H3–), 21.81 (s, 2C,
–(CH2CH3)2C6H3–). IR (liquid neat; cmꢂ1): 3356 (w), 2964 (s),
2873 (s), 1641 (w), 1589 (s), 1447 (s), 1375 (s), 1339 (s), 1275
(s), 1201 (s), 1149 (s), 1108 (s), 1053 (s), 994 (s), 886 (s), 808 (s),
750 (s), 621 (s).
2.2. Preparation of ligands and Pd(II) complexes
N-(pyridin-2-ylmethyl)aniline
ylmethyl)aniline (L2) and their (dichloro)palladium(II) complexes
([L2PdCl2]) are previously reported [16,39,43,46].
(L1),
4-methyl-N-(pyridin-2-
2.2.1. 3,5-Dimethyl-N-(pyridin-2-ylmethyl)aniline (L3)
3,5-Dimethylaniline (2.49 mL, 0.0200 mol) in dichloromethane
(20.0 mL) was added 2-pyridinecarboxaldehyde (1.90 mL,
0.0200 mol) in dichloromethane (20.0 mL). After 24 h stirring at
room temperature, the dichloromethane solution was dried over
the MgSO4. MgSO4 was filtered and the solvent was removed under
reduced pressure. Crude 3,5-dimethyl-N-(pyridin-2-ylmethyl-
ene)aniline product was reduced by sodium borohydride (2.0 eq.
0.650 g, 0.500 mol) in anhydrous methanol (20.0 ml). The reaction
mixture was stirred at room temperature for 24 h. The solvent was
removed and crude was vacuum distilled to obtain light red oil
(3.55 g, 83.6%). Anal. Calc. for C14H16N2: C, 79.21; H, 7.596; N,
13.20. Found: C, 79.01; H, 7.611; N, 12.98%. 1H NMR (CDCl3,
2.2.4. 4-Fluoro-N-(pyridin-2-ylmethyl)aniline (L6)
L6 was prepared by analogous method as described for L1
except utilizing 4-fluoroaniline (3.62 mL, 0.0200 mol) and 2-pyri-
dinecarboxaldehyde (1.90 mL, 0.0200 mol). The product was
obtained as light orange oil (3.55 g, 87.8%). Anal. Calc. for
C12H11N2F: C, 71.27; H, 5.482; N, 13.85, F, 9.394. Found: C, 71.09;
H, 5.471; N, 13.53, F, 9.373%. 1H NMR (CDCl3, 400 MHz): d 8.59 (d,
1H, J = 7.6 Hz, –NC5H4–), 7.66 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.35 (d,
1H, J = 7.6 Hz, –NC5H4–), 7.19 (d, 1H, J = 7.8 Hz, –NC5H4–), 6.78 (m,
2H, –FC6H4–), 6.63 (m, 2H, –FC6H4–), 4.50 (s, 1H, –NHFC6H4–),
4.42 (s, 2H, –CH2NC5H4–). 13C NMR (CDCl3, 100 MHz): d 159.85
(s, 1C, ipso-NC5H4–), 158.99 (s, 1C, –NC5H4–), 146.13 (s, 1C, ipso-
FC6H4–), 143.89 (s, 1C, p-FC6H4–), 121.71 (s, 1C, –NC5H4–),
118.72 (s, 1C, –NC5H4–), 115.65 (s, 2C, m-FC6H4–), 113.05 (s, 2C,
o-FC6H4–), 44.00 (s, 1C, –CH2NC5H10–). IR (liquid neat; cmꢂ1):
3356 (w), 2964 (s), 2873 (s), 1641 (w), 1589 (s), 1447 (s), 1375
(s), 1339 (s), 1275 (s), 1201 (s), 1149 (s), 1108 (s), 1053 (s), 994
(s), 886 (s), 808 (s), 750 (s), 621 (s).
400 MHz):
d 8.59 (d, 1H, J = 7.8 Hz, –NC5H4–), 8.17 (d, 1H,
J = 7.8 Hz, –NC5H4–), 7.82 (s, 1H, –NC5H4–), 7.74 (t, 1H, J = 7.8 Hz,
–NC5H4–), 6.58 (s, 1H, p-(CH3)2C6H3–), 6.32 (s, 2H, o-(CH3)2C6H3–),
4.49 (s, 1H, –NH(CH3)2C6H3–), 4.20 (s, 2H, –CH2NC5H4–), 2.39
(s, 6H, –(CH3)2C6H3–). 13C NMR (CDCl3, 100 MHz): d 160.12
(s, 1C, ipso-NC5H4–), 156.33 (s, 1C, –NC5H4–), 150.55 (s, 1C, ipso-
(CH3)2C6H3–), 133.89 (s, 1C, –NC5H4–), 140.86 (s, 2C, m-(CH3)2C6
H3–), 135.86 (s, 1C, –NC5H4–), 133.84 (s, 1C, –NC5H4–), 128.44
(s, 1C, p-(CH3)2C6H3–), 119.46 (s, 2C, o-(CH3)2C6H3–), 42.86 (s, 1C,
–CH2NC5H4–), 25.81 (s, 2C, –(CH3)2C6H3–). IR (liquid neat; cmꢂ1):
3395 (w), 3016 (s), 2916 (s), 2858 (w), 1683 (s), 1597 (s), 1510
(s), 1469 (s), 1428 (s), 1335 (s), 1187 (s), 1147 (s), 1119 (s), 1041
(s), 991 (s), 919 (s), 820 (s), 753 (s), 688 (s), 613 (s).
2.2.5. N-(Pyridin-2-ylmethyl)aniline (dichloro)palladium(II)
([L1PdCl2])
A solution of L1 (0.0870 g, 0.473 mol) in anhydrous ethanol
(10.0 mL) was added to a solution of [Pd(CH3CN)2Cl2] (0.122 g,
0.473 mol) [73,74], which is synthesized from the reaction
between anhydrous [PdCl2] and CH3CN by refluxing, in dried etha-
nol (10.0 mL). The reaction mixture was stirred 12 h at room tem-
perature. The solid residue was filtered and washed with ethanol
(10.0 mL ꢀ 2), followed by washing with diethyl ether
2.2.2. 2,4,6-Trimethyl-N-(pyridin-2-ylmethyl)aniline (L4)
L4 was prepared by analogous method as described for L3 except
utilizing 2,4,6-trimethylaniline (2.81 mL, 0.0200 mol) and 2-pyri-
dinecarboxaldehyde (1.90 mL, 0.0200 mol). The product was
obtained as light red oil (3.55 g, 78.4%). Anal. Calc. for C15H18N2:

68
S. Kim et al. / Polyhedron 77 (2014) 66–74
(10.0 mL ꢀ 2) to give a yellow solid (0.150 g, 88.3%). The X-ray
crystals of [L1PdCl2] were obtained within three days from diethyl
ether (10.0 mL) diffusion into a DMF solution (10.0 mL) of [L1PdCl2]
(0.0500 g). Anal. calculated for C12H12N2Cl2Pd: C, 39.86; H, 3.345;
N, 7.747. Found: C, 39.86; H, 3.379; N, 8.281%. mp (°C): 278. 1H
NMR (DMSO-d6, 400 MHz): 1H NMR (CDCl3, 400 MHz): d 8.71 (d,
1H, 3J = 6.0 Hz, –NHC6H5–), d 8.59 (d, 1H, J = 7.8 Hz, –NC5H4–),
7.65 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.63 (d, 1H, J = 7.6 Hz, –NC5H4–),
7.61 (t, 1H, J = 7.6 Hz, –NC5H4–), 7.34 (m, 3H, o,p-C6H5–), 6.97
(t, 2H, J = 7.4 Hz, m-NC6H5–), 4.46 (d, 2H, 3J = 14.8 Hz, 3J = 5.8 Hz,
–CH2NC5H4–), 3.93 (d, 2H, 2J = 14.8 Hz, 3J = 5.8 Hz, –CH2NC5H4–).
13C NMR (CDCl3, 100 MHz): d 159.73 (s, 1C, ipso-NC5H4–), 154.89
(s, 1C, ipso-C6H5–), 149.55 (s, 1C, –NC5H4–), 136.59 (s, 1C,
–NC5H4–), 125.08 (s, 2C, m-C6H5–), 120.98 (s, 1C, –NC5H4–),
120.69 (s, 1C, –NC5H4–), 119.89 (s, 1C, p-C6H5–), 111.89 (s, 2C,
o-C6H5–), 53.24 (s, 2C, –CH2NC5H4–). IR (solid neat; cmꢂ1): 3234
(w), 3038 (w), 2951 (s), 2872 (s), 1915 (w), 1835 (s), 1747 (s),
1693 (s), 1649 (s), 1596 (s), 1517 (s), 1472 (s), 1319 (s), 1107 (s),
1045 (s), 994 (s), 936 (s), 850 (s), 772 (s), 657 (s).
NMR (CDCl3, 100 MHz): d 160.12 (s, 1C, ipso-NC5H4–), 156.33
(s, 1C, –NC5H4–), 150.55 (s, 1C, ipso-(CH3)2C6H3–), 133.89 (s, 1C,
–NC5H4–), 140.86 (s, 2C, m-(CH3)2C6H3–), 135.86 (s, 1C, –NC5H4–
), 133.84 (s, 1C, –NC5H4–), 128.44 (s, 1C, p-(CH3)2C6H3–), 119.46
(s, 2C, o-(CH3)2C6H3–), 42.86 (s, 2C, –CH2NC5H4–), 25.81 (s, 2C, –
(CH3)2C6H3–). IR (solid neat; cmꢂ1): 3236 (w), 3039 (s), 2913 (s),
2667 (w), 1919 (s), 1834 (s), 1744 (s), 1694 (s), 1649 (s), 1601
(s), 1526 (s), 1474 (s), 1320 (s), 1243 (s), 1196 (s), 1093 (s), 1054
(s), 988 (s), 940 (s), 890 (s), 843 (s), 762 (s), 700 (s), 632 (s).
2.2.8. 2,4,6-Trimethyl-N-(pyridin-2-ylmethyl)aniline
(dichloro)palladium(II) ([L4PdCl2])
The [L4PdCl2] was prepared according to the similar procedure
described for [L1PdCl2] except utilizing L4 (0.106 g, 0.473 mol)
and [Pd(CH3CN)2Cl2] (0.122 g, 0.473 mol). The solid residue was fil-
tered and washed with ethanol (10.0 mL ꢀ 2), followed by washing
with diethyl ether (10.0 mL ꢀ 2) to give a yellow solid (0.170 g,
89.6%). The X-ray crystals of [L4PdCl2] were obtained within five
days from diethyl ether (10.0 mL) diffusion into a DMF solution
(10.0 mL) of [L4PdCl2] (0.0500 g). Anal. Calc. for C15H18N2Cl2Pd: C,
44.63; H, 4.494; N, 6.940. Found: C, 44.83; H, 3.840; N, 6.724%.
mp (°C): 295. 1H NMR (DMSO-d6, 400 MHz): d 8.92 (d, 1H,
3J = 5.6 Hz, –NH(CH3)3C6H2–), 8.12 (d, 1H, J = 7.6 Hz, –NC5H4–),
7.78 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.56 (d, 2H, J = 7.7 Hz, –NC5H4–),
6.91 (s, 1H, –(CH3)3C6H2–), 6.80 (s, 1H, –(CH3)3C6H2–), 4.52 (s,
1H, 2J = 11.2 Hz, 3J = 3.2 Hz, –CH2NC5H4–), 4.48 (s, 1H, 2J =
11.2 Hz, 3J = 3.2 Hz, –CH2NC5H4–), 3.08 (s, 3H, p-(CH3)3C6H2–),
2.29 (s, 3H, m-(CH3)3NC6H2–), 2.18 (s, 3H, m-(CH3)3NC6H2–). 13C
NMR (CDCl3, 100 MHz): d 164.35 (s, 1C, ipso-NC5H4–), 148.59
(s, 1C, –NC5H4–), 141.31 (s, 1C, ipso-(CH3)3C6H2–), 140.21 (s, 1C,
–NC5H4–), 135.60 (s, 1C, p-(CH3)3C6H2–), 131.16 (s, 1C, m-(CH3)3
C6H2–), 130.44 (s, 1C, o-(CH3)3C6H2–), 124.04 (s, 1C, –NC5H4–),
121.81 (s, 1C, –NC5H4–), 61.65 (s, 1C,–CH2NC5H4–), 20.63 (s, 2C,
m-(CH3)3C6H2–), 18.90 (s, 1C, p-(CH3)3C6H2–). IR (solid neat;
cmꢂ1): 3214 (w), 3117 (s), 3037 (s), 2973 (w), 2912 (s), 2730 (s),
1744 (s), 1695 (s), 1649 (s), 1615 (s), 1517 (s), 1480 (s), 1290 (s),
1198 (s), 1163 (s), 1115 (s), 987 (s), 863 (s), 824 (s), 769 (s), 703
(s), 593 (s).
2.2.6. 4-Methyl-N-(pyridin-2-ylmethyl)aniline (dichloro)palladium(II)
([L2PdCl2])
Although [L2PdCl2] was synthesized, there is no X-ray structure
reported [46]. Thus, the [L2PdCl2] was prepared according to a sim-
ilar procedure described for [L1PdCl2] except utilizing L2 (0.093 g,
0.473 mol) and [Pd(CH3CN)2Cl2] (0.122 g, 0.473 mol). The solid res-
idue was filtered and washed with ethanol (10.0 mL ꢀ 2), followed
by washing with diethyl ether (10.0 mL ꢀ 2) to give a yellow solid
(0.160 g, 90.6%). The X-ray crystals of [L2PdCl2] were obtained
within five days from diethyl ether (10.0 mL) diffusion into a DMF
solution (10.0 mL) of [L2PdCl2] (0.0500 g). Anal. Calc. for C13H14N2-
Cl2Pd: C, 41.57; H, 3.757; N, 7.458%. Found: C, 39.56; H, 3.670; N,
7.024%. mp (°C): 284. 1H NMR (DMSO-d6, 400 MHz): d 8.77 (d, 1H,
J = 7.8 Hz, –NC5H4–), d 8.70 (dd, 1H, 3J = 5.2 Hz, –NHC5H4–), 8.21
(t, 1H, J = 7.8 Hz, –NC5H4–), 7.78 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.62
(m, 4H, –(CH3)C6H4–), 7.13 (m, 2H, –(CH3)C6H4–), 7.01 (m, 2H,
–(CH3)C6H4–), 4.98 (dd, 1H, 2J = 17.4 Hz, 3J = 6.0 Hz –CH2NC5H4–),
4.36 (dd, 2H, 2J = 16.8 Hz, 3J = 5.2 Hz, –CH2NC5H4–), 2.81 (s, 3H,
–(CH3)C6H4–). 13C NMR (DMSO-d6, 100 MHz): d 159.72 (s, 1C,
ipso-NC5H4–), 154.78 (s, 1C, –NC5H4–), 149.59 (s, 1C, ipso-(CH3)
C6H4–), 126.98 (s, 2C, m-(CH3)C6H4–), 126.21 (s, 1C, p-(CH3)C6H4–),
120.69 (s, 1C, –NC5H4–), 118.69 (s, 1C, –NC5H4–), 115.48 (s, 2C,
o-(CH3)C6H4–), 110.38 (s, 1C, –NC5H4–), 58.78 (s, 1C, –CH2NC5H4–),
34.23 (s, 1C, –(CH3)C6H4–). IR (solid neat; cmꢂ1): 3275 (w), 3111
(s), 3009 (s), 2913 (w), 2775 (s), 2709 (s), 1920 (s), 1835 (s), 1745
(s), 1694 (s), 1649 (s), 1616 (s), 1525 (s), 1435 (s), 1323 (s), 1270
(s), 1214 (s), 1118 (s), 957 (s), 874 (s), 811 (s), 773 (s), 711 (s).
2.2.9. 2,6-Diethyl-N-(pyridin-2-ylmethyl)aniline
(dichloro)palladium(II) ([L5PdCl2])
The [L5PdCl2] was prepared according to the similar procedure
described for [L1PdCl2] except utilizing L5 (0.113 g, 0.473 mol) and
[Pd(CH3CN)2Cl2] (0.122 g, 0.473 mol). The solid residue was filtered
and washed with ethanol (10.0 mL ꢀ 2), followed by washing with
diethyl ether (10.0 mL ꢀ 2) to give a yellow solid (0.170 g, 86.6%).
The X-ray crystals of [L5PdCl2] were obtained within five days from
diethyl ether (10.0 mL) diffusion into a DMF solution (10.0 mL) of
[L5PdCl2] (0.0500 g). Anal. Calc. for C16H20N2Cl2Pd: C, 46.01; H,
4.826; N, 6.707. Found: C, 45.12; H, 4.054; N, 6.463%. mp (°C): 335.
1H NMR (DMSO-d6, 400 MHz): d 8.93 (d, 1H, 3J = 6.4 Hz, –NH
(CH2CH3)2C6H3–), 8.12 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.87 (d, 1H,
J = 7.6 Hz, –NC5H4–), 7.78 (d, 1H, J = 7.8 Hz, –NC5H4–), 7.58 (d, 1H,
J = 7.8 Hz, –NC5H4–), 7.21 (m, 2H, –(CH2CH3)2C6H3–), 7.01 (m, 1H,
–(CH2CH3)2C6H3–), 4.47 (s, 1H, 2J = 15.2 Hz, 3J = 7.6 Hz, –CH2NC5H4–),
4.24 (s, 1H, 2J = 15.2 Hz, 3J = 7.6 Hz, –CH2NC5H4–) 1.43 (s, 6H, –(CH2
CH3)2C6H3–), 1.21 (s, 4H, –(CH2 CH3)2C6H3–). 13C NMR (CDCl3,
100 MHz): d 163.89 (s, 1C, ipso-NC5H4–), 148.58 (s, 1C, –NC5H4–),
142.16 (s, 1C, ipso-(CH2CH3)2C6 H3–), 140.22 (s, 1C, –NC5H4–),
137.06 (s, 1C, –NC5H4–), 136.42 (s, 1C, –NC5H4–), 127.06 (s, 2C,
m-(CH2CH3)2C6H3–), 124.09 (o-(CH2CH3)2C6H3–), 121.83 (s, 1C,
p-(CH2CH3)2C6H3–), 63.22 (s, 1C, –CH2NC5H4–), 24.62 (s, 2C, –(CH2
CH3)2C6H3–), 16.06 (s, 2C, –(CH2CH3)2C6H3–). IR (solid neat; cmꢂ1):
3213 (w), 3111 (s), 3023 (s), 2971 (w), 2880 (s), 1919 (s), 1833 (s),
1744 (s), 1692 (s), 1649 (s), 1448 (s), 1388 (s), 1332 (s), 1222 (s),
2.2.7. 3,5-Dimethyl-N-(pyridin-2-ylmethyl)aniline
(dichloro)palladium(II) ([L3PdCl2])
The [L3PdCl2] was prepared according to the similar procedure
described for [L1PdCl2] except utilizing L3 (0.100 g, 0.473 mol)
and [Pd(CH3CN)2Cl2] (0.122 g, 0.473 mol). The solid residue was fil-
tered and washed with ethanol (10.0 mL ꢀ 2), followed by washing
with diethyl ether (10.0 mL ꢀ 2) to give a yellow solid (0.170 g,
92.8%). The X-ray crystals of [L3PdCl2] were obtained within five
days from diethyl ether (10.0 mL) diffusion into an DMF solution
(10.0 mL) of [L3PdCl2] (0.0500 g). Anal. Calc. for C14H16N2Cl2Pd: C,
43.16; H, 4.139; N, 7.190. Found: C, 43.03; H, 4.082; N, 7.130%.
mp (°C): 294. 1H NMR (DMSO-d6, 400 MHz):
d 8.77(d, 1H,
3J = 6.0 Hz, –NH(CH3)2C6H3–), d 8.65 (d, 1H, J = 7.8 Hz, –NC5H4–),
8.52 (d, 1H, J = 7.8 Hz, –NC5H4–), 8.19 (s, 1H, –NC5H4–), 7.77
(t, 1H, J = 7.8 Hz, –NC5H4–), 7.61 (s, 1H, p-(CH3)2C6H3–), 7.34
(s, 2H, o-(CH3)2C6H3–), 4.96 (s, 1H, 2J = 17.2 Hz, 3J = 6.4 Hz, –CH2
(CH3)2C6H3–), 4.36 (s, 1H, 2J = 17.2 Hz, 3J = 6.4 Hz, –CH2(CH3)2C6
H3–), 2.20 (s, 3H, –(CH3)2C6H3–), 2.09 (s, 3H, –(CH3)2C6H3–). 13C

S. Kim et al. / Polyhedron 77 (2014) 66–74
69
1158 (s), 1116 (s), 1052 (s), 989 (s), 952 (s), 862 (s), 811 (s), 762 (s),
712 (s).
solution was stirred for 30 min at 0, 25 and 60 °C, respectively.
The MMA (5.00 mL, 47.1 mmol) was added to the above reaction
mixture and stirred for 2 h to obtain a viscous solution. Methanol
(2.00 mL) was added to terminate polymerization. The reaction
mixture was poured into a large quantity of MeOH (500 mL), and
35% HCl (5.00 mL) was injected to remove the remaining co-cata-
lyst MMAO. PMMA was obtained by filtration and repeating wash-
ing with methanol (250 mL ꢀ 2), and dried under vacuum for 24 h.
2.2.10. 4-Fluoro-N-(pyridin-2-ylmethyl)aniline
(dichloro)palladium(II) ([L6PdCl2])
The [L6PdCl2] was prepared according to a similar procedure
described for [L1PdCl2] except utilizing L6 (0.0950 g, 0.473 mol)
and [Pd(CH3CN)2Cl2] (0.122 g, 0.473 mol). The solid residue was fil-
tered and washed with ethanol (10.0 mL ꢀ 2), followed by washing
with diethyl ether (10.0 mL ꢀ 2) to give a yellow solid (0.160 g,
89.7%). The X-ray crystals of [L6PdCl2] were obtained within five
days from diethyl ether (10.0 mL) diffusion into a DMF solution
(10.0 mL) of [L6PdCl2] (0.0500 g). Anal. Calc. for C12H11FN2Cl2Pd:
C, 37.97; H, 2.921; N, 7.381. Found: C, 38.03; H, 2.833; N, 7.890%.
mp (°C): 285. 1H NMR (DMSO-d6, 400 MHz): d 8.55 (d, 1H,
J = 7.6 Hz, –NC5H4–), 7.79 (d broad, 1H, –NHFC6H4–), 7.39 (d, 1H,
J = 7.6 Hz, –NC5H4–), 7.30 (d, 1H, J = 7.6 Hz, –NC5H4–), 7.27 (d,
1H, J = 7.6 Hz, –NC5H4–), 6.92 (m, 2H, –FC6H4–), 6.60 (m, 2H,
–FC6H4–), 4.34 (dd, 1H, 2J = 14.8 Hz, 3J = 6.4 Hz, –CH2NC5H4–),
4.32 (dd, 1H, 2J = 14.8 Hz, 3J = 6.4 Hz, –CH2NC5H4–). 13C NMR
(DMSO-d6, 100 MHz): d 163.87 (s, 1C, ipso-NC5H4–), 160.00 (s, 1C,
p-FC6H4–), 155.83 (s, 1C, –NC5H4–), 153.54 (s, 1C, –NC5H4–), 149.26
(s, 2C, m-FC6H4–), 137.08 (s, 1C, ipso-FC6H4–), 124.75
(s, 1C, –NC5H4–), 116.51 (s, 1C, –NC5H4–), 115.52 (s, 2C, o-FC6H4–),
61.37 (s, 1C, –CH2NC5H4). IR (solid neat; cmꢂ1): 3273 (w), 3118
(s), 3043 (s), 2895 (w), 2765 (s), 2703 (s), 1834 (s), 1745 (s),
1694 (s), 1650 (s), 1613 (s), 1508 (s), 1330 (s), 1220 (s), 1110 (s),
1053 (s), 1016 (s), 957 (s), 821 (s), 771 (s), 616 (s).
3. Results and discussion
3.1. Synthesis and chemical properties
Synthesis of N0-substituted pyridylmethylaniline ligands (L3–L6)
was achieved through the condensation reaction between the
appropriate aniline and 2-pyridinecarboxaldehyde, followed by
reduction of the imine residue in anhydrous methanol by sodium
borohydride (Scheme 1). Final ligands were obtained at yields
ranging from 74% to 88%. Ligands L1 and L2 were reported
previously and have been applied to palladium, platinum, and ruthe-
nium complexes [16,39,43,46]. Complexes [LnPdCl2] (Ln = L1–L6)
were obtained from the corresponding ligands with [Pd(CH3CN)2
Cl2] in anhydrous ethanol, with yields around 90%. 1H NMR, 13C
NMR, and elemental analyses were consistent with ligand and
Pd(II) complex formation.
The 1H NMR characterisation of complexes [LnPdCl2] (Ln = L1–
L6) was performed in d6-DMSO solution due to the low solubility
in solvents less polar than DMSO. 1H NMR spectra showed a
well-resolved ABX spin system for the hydrogen atoms of the dia-
stereotopic methylene group of the chelating ring (HA and HB) and
the aniline hydrogen atom (HX) in [LnPdCl2] (Ln = L1–L6) (Table 1).
For example, signals corresponding to these diastereotopic AB
nuclei were separated by maximum value of d 0.64 for [L2PdCl2]
and minimum value of d 0.02 for [L6PdCl2]. The coupling constant
between these two nuclei, 2JAB ranged from 14.8 to 17.9 Hz. On the
other hand, chemical shifts of the diastereotopic methylene group
in ligands showed only one broad peak, ranged from d 3.91 to d
4.93. For the hydrogen (HX) of the aniline moiety, 1H NMR peaks
of [LnPdCl2] (Ln = L1–L6) complexes (d 7.78–8.91) were shifted
toward the low field compared with the corresponding ligands,
ranged from d 4.50 to d 4.77 as a singlet. The coupling constant
3JAX, which is resulted from X nucleus on aniline moiety and HA
or HB nuclei of methylene carbon, ranged from 5.6 to 7.6 Hz.
2.3. X-ray crystallographic studies
A colorless cubic-shaped crystal was picked up with paraton oil
and mounted on a Bruker SMART CCD diffractometer equipped
with a graphite-monochromated Mo K
a (k = 0.71073 Å) radiation
source and a nitrogen cold stream (200 K). Data collection and
integration were performed with SMART (Bruker, 2000) and SAINT-PLUS
(Bruker, 2001) [75]. Semiempirical absorption corrections based on
equivalent reflections were applied by SADABS [76]. The structure
was solved by direct methods and refined by full-matrix least-
squares on F2 using SHELXTL [77]. All the non-hydrogen atoms were
refined anisotropically, and hydrogen atoms were added to their
geometrically ideal positions. Crystal and structure refinement
data for all structures are summarized in Table 1.
2.4. Catalytic activity for MMA polymerization
3.2. Crystal structures
In a Schlenk line, the complex (15.0
l
mol, 5.40 mg for [L1PdCl2];
ORTEP drawings of complexes are shown in Fig. 1 ([L1PdCl2]),
Fig. 2 ([L2PdCl2]), Fig. 3 ([L3PdCl2]), Fig. 4 ([L4PdCl2]), Fig. 5 ([L5
PdCl2]), and Fig. 6 ([L6PdCl2]). Crystal data and structural refine-
ment for Pd(II) complexes are shown in Table 2. The selected bond
lengths and angles are listed in Table 3. A single crystal suitable for
5.60 mg for [L2PdCl2]; 5.80 mg for [L3PdCl2]; 6.10 mg for [L4PdCl2];
6.30 mg for [L5PdCl2]; 5.70 mg for [L6PdCl2]) was dissolved in dried
toluene (10.0 mL) followed by the addition of modified methylalu-
minoxane (MMAO) (3.25 mL, 7.50 mmol) as a cocatalyst. The
Table 1
Chemical shift and coupling constant for the diastereotopic methylenic hydrogens (Ha and Hb) and hydrogen (Hx) of aniline moiety.
Complexes
d Ha(PyCH2–NHR)
d Hb(PyCH2–NHR)
2J(HaHb) (Hz)
3J(HaHx) (Hz)
d Hx(PyCH2–NHR)
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
4.51 (4.46)a
4.98 (4.42)
4.93 (3.91)
4.53 (4.20)
4.47 (4.93)
4.34 (4.42)
3.98
4.34
4.33
4.47
4.19
4.32
14.8
16.8
17.2
17.9
15.2
15.2
5.6
6.0
6.4
7.2
7.6
6.0
8.70 (4.77)b
8.70 (4.59)
8.77 (4.49)
8.91 (4.51)
8.92 (4.63)
7.78 (4.50)
a
Chemical shifts of diastereotopic methylenic hydrogens on pyridine amine moiety in ligands Ln (Ln = L1–L6) were presented in the prentice. The peak was not resolved and
appeared as broad.
b
Chemical shifts of the hydrogen on aniline moiety in ligands Ln (Ln = L1–L6) were presented in the prentice. The peak was not resolved and appeared as broad.

70
S. Kim et al. / Polyhedron 77 (2014) 66–74
NH2
R1
R2
R1
R2
R1
R2
O
H
(1) CH2Cl2/rt, 24 h
R3
NH
N
+
(2) NaBH4
MeOH/rt, 24 h
N
R2
R1
R3
L1 (R1 = R2 = R3 = H); L2 (R1 = R2 = H, R3 = Me)
3 (R1 = R3 = H, R2 = Me); L4 (R1 = R3 = Me, R2 = H)
5 (R1 = Et, R2 = R3 = H); L6 (R1 = R2 = H, R3 = F)
L
L
H
R1
R1
R2
N
EtOH
R2
rt, 12 h
N
[Pd(CH3CN)2Cl2]
+
R3
NH
N
Pd
Cl
R3
R1
Cl
R2
R1
R2
[L1PdCl2] (R1 = R2 = R3 = H); [L2PdCl2] (R1 = R2 = H, R3 = Me)
[L3PdCl2] (R1 = R3 = H, R2 = Me); [L4PdCl2] (R1 = R3 = Me, R2 = H)
[L5PdCl2] (R1 = Et, R2 = R3 = H); [L6PdCl2] (R1 = R2 = H, R3 = F)
Scheme 1. Synthesis of ligands Ln (Ln = L1–L6) and the corresponding Pd(II) complexes [LnPdCl2].
C10
C4
C5
C3
C4
C9
C6
C9
C11
C8
C8
C5
C10
C11
C3
C6
C13
C7
C2
C12
C14
C2
N2
C7
N1
C1
N2
N1
C12
C1
Pd1
Pd1
Cl1
Fig. 3. ORTEP Drawing of [L3PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.
Cl
Cl
Fig. 1. ORTEP Drawing of [L1PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.
C12
C10
C11
C13
C9
C6
C4
C3
C8
C5
C4
C9
C3
C14
C2
C8
C7
C10
C6
C5
C11
N1
N
C1
C2
C1
C7
N2
Pd1
N1
C12
C1
C13
Cl2
Cl1
Fig. 4. ORTEP Drawing of [L4PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.
Pd1
X-ray crystallography was obtained from diethyl ether (10.0 mL)
diffusion into DMF solution (10.0 mL). The coordination geometry
around the Pd(II) centre of the synthesised complexes can be
described as a slightly distorted square plane, consisting of the
two N atoms and two Cl atoms.
Cl2
Cl1
Fig. 2. ORTEP Drawing of [L2PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.

S. Kim et al. / Polyhedron 77 (2014) 66–74
71
C1
C9
F1C
C10
C3
C1
C8
C4
N1
C4
C14
C3
C15
C2
C6
C5
C11
C12
C5
C7
C6
C7
C2
C1
C12
N2
C11
N2
C8
C10
N1
C1
Pd1
C9
Pd1
Cl2
Cl1
Cl2
Cl1
Fig. 6. ORTEP Drawing of [L6PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.
Fig. 5. ORTEP Drawing of [L5PdCl2] with thermal ellipsoids at 50% probability. All
hydrogen atoms are omitted for clarity.
the complexes ranged from 1.450(12)–1.513(8) Å, reflecting the
The bond lengths of Pd–Npyridine [Pd(1)–N(1)] in [LnPdCl2]
(Ln = L1–L6) ranged from 2.023(5)–2.040(5) Å, while that of Pd–
Naniline [Pd(1)–N(2)] ranged from 2.040(6)–2.076(5) Å. The Pd–Cl
bond lengths ranged from 2.2862(18)–2.315(3) Å. Naniline–Cmethylene
[N(2)–C(6)] bond distances of the complexes ranged from
1.474(11)–1.512(12) Å, which were in the range of accepted
carbon–nitrogen single bonds. The C(5)–C(6) bond distances of
lack of delocalised
p-electrons in the pyridine ring [39,43,46].
Complexes [LnPdCl2] (Ln = L3, L4, L6) showed more distorted square
planarity than [LnPdCl2] (Ln = L1, L2, L5). It judged from that for
example, N(1)–Pd(1)–Cl(2) and N(2)–Pd(1)–Cl(1) angles in [L5
PdCl2] were 174.58(14)° and 176.37(14)°, respectively. However,
those angles for complex [L5PdCl2] were 169.66(19)° and
175.59(19)°, respectively. The average N(1)–Pd(1)–N(2) bond angle
Table 2
Crystal data and structure refinement for [LnPdCl2] (Ln = L1–L6) complexes.
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
Empirical formula
C12 H12 Cl2 N2 Pd
2(C13H14Cl2N2Pd),
C3H7NO
C14H16Cl2N2Pd
C15H18Cl2N2Pd
C16H20Cl2N2Pd
C12H11Cl2FN2Pd
Formula weight
T (K)
361.54
200(2)
824.22
200(2)
386.59
200(2)
403.61
200(2)
417.64
200(2)
379.53
200(2)
k (Å)
0.71073
monoclinic
C2/c
0.71073
triclinic
0.71073
monoclinic
P2(1)/C
0.71073
monoclinic
P2(1)/C
0.71073
monoclinic
P2(1)/n
0.71073
monoclinic
P2(1)/n
Crystal system
Space group
Unit cell dimensions0
a (Å)
b (Å)
c (Å)
ꢀ
P1
17.9510(6)
18.4840(6)
17.8230(6)
90.
119.5390(10)
90
5145.1(3)
16
1.867
8.5575(10)
11.8094(14)
16.4176(18)
78.174(3)
89.381(3)
82.718(2)
1610.6(3)
2
11.8902(14)
9.4194(10)
13.2955(15)
90
97.377(2)
90
1476.8(3)
4
1.752
11.4477(11)
14.8515(14)
18.5681(17)
90
92.115(2)
90
3154.7(5)
4
1.700
8.9107(10)
8.9104(10)
21.308(2)
90
101.075(2)
90
1660.3(3)
8
1.671
10.0955(6)
8.4942(5)
15.1538(10)
90
95.3940(10)
90
1293.73(14)
4
1.949
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (Mg/m3)
1.700
Absorption coefficient
1.835
1.480
1.605
1.506
1.434
1.840
(mmꢂ1
)
F(000)
2848
824
776
1616
840
744
Crystal size (mm3)
Theta range for data
collection (°)
0.37 ꢀ 0.30 ꢀ 0.14
0.26 ꢀ 0.12 ꢀ 0.09
0.28 ꢀ 0.19 ꢀ 0.17
0.27 ꢀ 0.15 ꢀ 0.13
0.27 ꢀ 0.16 ꢀ 0.09
0.16 ꢀ 0.14 ꢀ 0.08
1.71–28.28
1.27–26.06
1.73–28.34
1.76–28.32
2.35–26.03
2.33–28.29
Index ranges
Reflections collected
ꢂ13 6 h 6 23
ꢂ24 6 k 6 23
ꢂ23 6 l 6 23
17712
ꢂ10 6 h 6 10
ꢂ14 6 k 6 12
ꢂ20 6 l 6 13
10267
ꢂ15 6 h 6 15
ꢂ12 6 k 6 8
ꢂ15 6 l 6 17
10399
ꢂ15 6 h 6 15
ꢂ18 6 k 6 19
ꢂ21 6 l 6 24
23284
ꢂ11 6 h 6 9
ꢂ11 6 k 6 9
ꢂ26 6 l 6 26
9952
ꢂ12 6 h 6 13
ꢂ11 6 k 6 11
ꢂ20 6 l 6 18
9210
Independent reflections
6272 (0.0264)
6312 (0.0425)
3623 (0.0302)
7818 (0.0749)
3246 (0.0264)
3197 (0.0410)
(Rint
)
Completeness to
theta = 28.30°
98.40%
98.80%
98.20%
99.40%
99.30%
99.30%
Absorption correction
none
none
none
none
none
none
Refinement method
full-matrix least-
squares on F2
6272/0/307
full-matrix least-
squares on F2
6312/36/375
1.121
full-matrix least-
squares on F2
3623/0/174
1.219
full-matrix least-
squares on F2
7818/12/367
1.033
full-matrix least-
squares on F2
3246/0/192
1.158
full-matrix least-
squares on F2
3197/0/0.7573
1.174
Data/restraints/parameters
Goodness-of-fit (GOF) on F2 1.163
Final R indices [I > 2
r
(I)]
R1 = 0.0357
wR2 = 0.0800
R1 = 0.0587
wR2 = 0.1386
1.350 and ꢂ2.072
R1 = 0.0899
wR2 = 0.2368
R1 = 0.1385
wR2 = 0.3590
3.226 and ꢂ2.830
R1 = 0.0556
wR2 = 0.1637
R1 = 0.0860
wR2 = 0.2720
2.388 and ꢂ2.981
R1 = 0.0538
wR2 = 0.1197
R1 = 0.1205
wR2 = 0.1890
1.367 and ꢂ2.721
R1 = 0.0357
wR2 = 0.0794
R1 = 0.0534
wR2 = 0.1231
0.746 and ꢂ0.985
R1 = 0.0506
wR2 = 0.1059
R1 = 0.0980
wR2 = 0.1813
2.156 and ꢂ3.880
R indices (all data)
Largest difference in peak
and hole (e Åꢂ3
)

72
S. Kim et al. / Polyhedron 77 (2014) 66–74
Table 3
The selected bond lengths (Å) and angles (°) of [LnPdCl2] (Ln = L1–L6) complexes.
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
Bond lengths
Pd(1)–N(1)–
2.025(5)
Pd(1)–
N(1)
Pd(1)–
N(2)
Pd(1)–
Cl(1)
Pd(1)–
Cl(2)
2.040(10) Pd(1)–
2.026(6)
2.040(6)
Pd(1)–
N(2)
Pd(1)–
N(1)
2.023(5)
2.068(5)
Pd(1)–
N(1)
Pd(1)–
N(2)
2.040(5)
2.068(5)
Pd(1)–
N(1)
Pd(1)–
N(2)
2.031(7)
2.063(9)
2.307(2)
2.284(2)
N(1)
2.058(10) Pd(1)–
N(2)
Pd(1)–N(2)
Pd(1)–Cl(1)
Pd(1)–Cl(2)
2.076(5)
2.2948(15)
2.3134(15)
2.315(3)
Pd(1)–
Cl(1)
2.3108(19) Pd(1)–
Cl(2)
2.2909(19) Pd(1)–
Cl(1)
2.2862(18) Pd(1)–
Cl(1)
2.2992(18) Pd(1)–
Cl(2)
2.2924(16) Pd(1)–
Cl(1)
2.2973(15) Pd(1)–
Cl(2)
2.293(3)
Pd(1)–
Cl(2)
N(1)–C(5)
N(2)–C(6)
N(2)–C(7)
C(5)–C(6)
1.358(8)
1.502(8)
1.438(8)
1.503(9)
N(1)–C(5)
N(2)–C(6)
N(2)–C(7)
C(5)–C(6)
1.316(16) N(1)–C(5)
1.519(15) N(2)–C(6)
1.465(17) N(2)–C(7)
1.505(17) C(5)–C(6)
1.369(10)
1.474(11)
1.475(9)
N(1)–C(5)
1.343(8)
1.507(8)
1.473(8)
1.502(9)
N(1)–C(5)
1.352(7)
1.482(8)
1.476(7)
1.513(8)
N(1)–C(5)
1.354(12)
1.512(12)
1.450(11)
1.504(13)
N(2)–C(6)
N(2)–C(7)
C(5)–C(6)
N(2)–C(6)
N(2)–C(7)
C(5)–C(6)
N(2)–C(6)
N(2)–C(7)
C(5)–C(6)
1.450(12)
Bond angles
N(1)–Pd(1)–N(2)
82.1(2)
N(1)–
Pd(1)–
N(2)
N(1)–
Pd(1)–
Cl(2)
N(2)–
Pd(1)–
Cl(2)
N(1)–
Pd(1)–
Cl(1)
82.4(4)
171.3(3)
90.1(3)
94.4(3)
173.3(3)
N(1)–
Pd(1)–
N(2)
N(1)–
Pd(1)–
Cl(2)
N(2)–
Pd(1)–
Cl(2)
N(1)–
Pd(1)–
Cl(1)
81.4(3)
N(1)–
Pd(1)–
N(2)
83.6(2)
N(1)–
Pd(1)–
N(2)
82.96(19)
N(1)–
Pd(1)–
N(2)
82.7(3)
173.4(2)
90.8(2)
94.7(2)
177.3(2)
91.78(9)
N(1)–Pd(1)–Cl(2)
N(2)–Pd(1)–Cl(2)
N(1)–Pd(1)–Cl(1)
N(2)–Pd(1)–Cl(1)
Cl(1)–Pd(1)–Cl(2)
174.24(14)
94.09(15)
93.76(15)
169.66(19) N(1)–
Pd(1)–
174.42(16) N(1)–
Pd(1)–
174.58(14) N(1)–
Pd(1)–
Cl(2)
Cl(2)
Cl(2)
90.18(19)
95.90(19)
N(2)–
Pd(1)–
Cl(2)
N(1)–
Pd(1)–
Cl(1)
90.98(15)
94.71(16)
N(2)–
Pd(1)–
Cl(2)
N(1)–
Pd(1)–
Cl(1)
91.80(14)
94.26(13)
N(2)–
Pd(1)–
Cl(2)
N(1)–
Pd(1)–
Cl(1)
175.672(15) N(2)–
N(2)–
Pd(1)–
Cl(1)
175.59(19) N(2)–
Pd(1)–
177.65(15) N(2)–
Pd(1)–
176.37(14) N(2)–
Pd(1)–
Pd(1)–
Cl(1)
Cl(1)–
Pd(1)–
Cl(2)
Cl(1)
Cl(1)
Cl(1)
90.10(6)
93.51(12) Cl(1)–
Pd(1)–
92.84(7)
Cl(1)–
Pd(1)–
Cl(2)
90.72(7)
Cl(1)–
Pd(1)–
Cl(2)
90.91(6)
Cl(1)–
Pd(1)–
Cl(2)
Cl(2)
C(6)–N(2)–C(7)
C(6)–N(2)–Pd(1)
113.0(5)
107.3(4)
C(6)–
N(2)–C(7)
C(6)–
113.3(10) C(6)–
115.1(6)
106.9(5)
C(6)–
N(2)–C(7)
C(6)–
114.3(5)
109.4(4)
C(6)–
N(2)–C(7)
C(6)–
114.0(5)
110.7(4)
C(6)–
N(2)–C(7)
C(6)–
115.3(8)
105.5(5)
N(2)–C(7)
C(6)–
106.1(7)
N(2)–
Pd(1)
N(2)–
Pd(1)
N(2)–
Pd(1)
N(2)–
Pd(1)
N(2)–
Pd(1)
of five-membered rings ranged from 81.4(3)–83.6(2)° and were
slightly affected by aniline rings. The Cl(1)–Pd(1)–Cl(2) angles in
[LnPdCl2] (Ln = L1–L6) ranged between 90.10(6)° and 93.51(12)°,
which were traditional angles for square-planar coordination com-
plexes. Compared to the inter-location on the plane of the aniline
group and the plane of the palladium and pyridine in [L2PdCl2],
the plane of the aniline group and the plane of palladium and pyr-
idine in [LnPdCl2] (Ln = L1, L3, L6) were slightly twisted by ca. 10–
15° rather than being exactly perpendicular (90°), as observed for
specifically [LnPdCl2] (Ln = L4, L5).
fact that the MMA polymerisation activity of complex [L4PdCl2]
(1.41 ꢀ 105 g PMMA/mol Pdꢁh), which has methyl group on two
ortho position of aniline ring, was significantly higher than that
of complex [L5PdCl2] (2.73 ꢀ 104 g PMMA/mol Pd h), which has
ethyl group on two ortho position of aniline ring. This may resulted
from the increased solubility of [L4PdCl2] in toluene due to the
three methyl groups on the aniline ring moiety, compared to other
Pd(II) complexes. Excluding complex [L2PdCl2], which has moder-
ate MMA polymerisation activity, the structure of [L4PdCl2] was
very similar to the other Pd(II) complexes, in which the two planes
of the metallacyclic ring contain the pyridine and aniline ring.
Thus, the aniline ring moiety would not interfere with the environ-
ment of the palladium metal centre.
3.3. MMA polymerisation
The syndiotacticity of PMMA was around 0.70, which was sim-
ilar to all [LnPdCl2] (Ln = L1–L6) and to the starting material,
[Pd(CH3CN)2Cl2], regardless of the polymerisation temperature.
For comparison, Cu(II) complexes with ligand N-(2-furanylmethyl)-
N-(1–3,5-dimethyl-1H-pyrazolylmethyl)-N-(phenylmethyl)amines
[68] were reported to be active catalysts for the MMA polymerisa-
tion to yield syndiotactic PMMA with an rr value up to 0.78. How-
ever, the conversion of MMA to PMMA was only 30%. In addition,
Ni(II) complexes with ligands such as pentane-2,4-diol and
phenoxy-imine showed syndiotacticity, ranging from 0.73 to 0.82
with activity of 4.20 ꢀ 104 g PMMA/mol Ni h [61,64,81–84]. Co(II)
complexes with phenoxy-imine [62] and Fe(II) complexes with
pyridylmethylamine [85] were also used as catalysts for MMA
polymerisation with moderate activity and syndiotacticity. The
moderate syndiotacticity of these Pd(II) complexes was not suffi-
cient to confer a mechanism of coordination polymerisation, and
All Pd(II) complexes were activated by co-catalyst MMAO to
polymerise MMA [61,62,65], yielding PMMA with Tg ranging from
124 to 132 °C. Polymers were isolated as white solids and charac-
terised by gel permeation chromatography (GPC) in THF using
standard polystyrene as a reference. The triad microstructure of
PMMA was analysed using 1H-NMR spectroscopy [78–80]. The tac-
ticity of PMMA ranged around syndiotactic (rr, d 0.85), atactic (mr,
d 1.02), and isotactic (mm, d 1.21). The polymerisation results,
including tacticity and polydispersity index (PDI), which represent
the average degree of polymerisation in terms of the number of
structural units and molecules, are summarised in Table 4.
To confirm the catalytic activity of MMA polymerisation, blank
polymerisation of MMA was performed with [Pd(CH3CN)2Cl2] and
MMAO, respectively, at specific temperatures. The catalytic activi-
ties of the Pd(II) complexes were not significantly affected by steric
effects of ligands around the metal centre. This is supported by the

S. Kim et al. / Polyhedron 77 (2014) 66–74
73
Table 4
MMA Polymerization by [LnPdCl2] (Ln = L1–L6) complexes in the presence of MMAO.
d
e
f
Entry
Catalysta
Temp. (time) °C (h)
Yieldb (%)
Activityc (g/molCat h) ꢀ 104
Tg (°C)
Tacticity
%mm
Mw (g/mol) ꢀ 105
Mw/Mn
%mr
%rr
g
g
g
1
2
3
4
5
6
7
8
11
12
13
14
15
16
17
18
21
22
23
24
25
26
27
28
Pd(AN)2Cl2
MMAOh
60 (2 h)
60 (2 h)
60 (2 h)
60 (2 h)
60 (2 h)
60 (2 h)
60 (2 h)
60 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
25 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
0 (2 h)
18.8
8.97
22.9
15.6
18.8
71.2
17.5
16.0
39.1
2.99
23.3
25.2
21.4
22.6
17.3
5.56
8.11
2.56
3.85
5.77
2.14
5.56
4.70
4.27
2.93
1.40
3.57
2.43
2.93
14.1
2.73
2.50
1.83
0.47
3.63
3.93
3.33
3.53
2.70
0.87
1.27
0.40
0.60
0.90
0.33
0.87
0.73
0.67
131
120
129
130
130
128
126
130
130
125
130
128
129
128
126
128
129
130
131
129
130
128
128
129
7.60
37.2
6.70
8.30
8.30
8.10
8.10
7.20
8.80
15.4
7.90
8.00
7.70
8.10
8.10
14.1
9.20
11.6
13.7
11.4
8.30
10.1
8.10
10.8
22.8
10.9
26.8
23.6
23.6
22.7
22.9
21.5
19.7
28.4
17.8
19.0
22.5
22.7
22.9
25.4
18.9
28.8
21.6
22.3
23.6
26.8
22.7
20.4
69.6
51.9
66.5
68.1
68.1
69.2
69.0
71.3
71.5
56.2
74.3
73.0
69.8
69.2
69.0
60.5
71.9
59.6
64.7
66.3
68.1
63.1
69.2
68.8
0.66
0.61
8.60
0.47
0.92
9.76
8.42
1.80
0.72
0.66
1.23
0.78
1.22
2.16
8.42
0.56
9.93
3.25
8.13
10.11
0.98
0.67
1.27
0.93
2.90
2.20
1.98
2.15
2.28
1.61
1.92
2.50
2.97
1.32
1.59
1.56
1.86
1.73
1.92
2.37
1.70
2.56
2.10
1.71
2.17
1.17
1.73
1.99
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
Pd(AN)2Cl2
MMAOh
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
Pd(AN)2Cl2
MMAOh
[L1PdCl2]
[L2PdCl2]
[L3PdCl2]
[L4PdCl2]
[L5PdCl2]
[L6PdCl2]
a
b
c
[Pd(II) catalyst]0 = 15 lmol, and [MMA]0/[MMAO]0/[Pd(II) catalyst]0 = 3100:500:1.
Yield defined a mass of dried polymer recovered/mass of monomer used.
Activity is g of PMMA/(mol Pdꢁh).
d
e
f
Tg is glass transition temperature which is determined by a thermal analyzer.
Determined by gel permeation chromatography (GPC) eluted with THF at room temperature by filtration with polystyrene calibration.
Mn refers the number average of molecular weights of PMMA.
AN refers CH3CN in Pd(AN)2Cl2. It is a blank polymerization in which Pd(AN)2Cl2 was also activated by MMAO.
It is a blank polymerization which was done solely by MMAO.
g
h
the steric effect in [LnPdCl2] (Ln = L1–L6) was not observed during
MMA polymerisation. This result is comparable to previously
reported Pd(II) complexes containing the bispyridylamine ligand,
N,N-di(2-picolyl)cycloheptylamine, which clearly showed the ste-
ric and electronic effect of Pd(II) complexes during MMA polymer-
isation [70]. However, structural differences tuned by phenyl ring
of imine moiety in [LnPdCl2] (Ln = L1–L6) did not sufficiently induce
the steric hindrance on the palladium metal centre to show
improved activity and syndiotacticity during MMA polymerisation.
Appendix A. Supplementary data
CCDC 984067–984072 contain the supplementary crystallo-
graphic data for [L1PdCl2], [L2PdCl2], [L3PdCl2], [L4PdCl2], [L5PdCl2]
and [L6PdCl2], respectively. These data can be obtained free of
charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or
from the Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336 033; or e-mail:
deposit@ccdc.cam.ac.uk.
References
4. Conclusions
[1] D.J. Ayres, D.A. House, W.T. Robinson, Inorg. Chim. Acta 277 (1998) 177.
[2] H.M. Helis, W.H. Goodman, R.B. Wilson, J.A. Morgan, D.J. Hodgson, Inorg. Chem.
16 (1977) 2412.
[3] T. Zhu, Z. Guang-Yi, L. Xue-Qiang, X. Sai-Feng, Z. Qian-Jiang, W.G. Jackson, W.
Zhan-Bing, L. La-Sheng, Inorg. Chim. Acta 357 (2004) 953.
[4] C.J. O’Connor, E.E. Eduok, F.R. Fronczek, O. Kahn, Inorg. Chim. Acta 105 (1985)
107.
[5] S. Schouteeten, O.R. Allen, A.D. Haley, G.L. Ong, G.D. Jones, D.A. Vicic, J.
Organomet. Chem. 691 (2006) 4975.
[6] L. Toma, R. Lescouëzec, J. Vaissermann, P. Herson, V. Marvaud, F. Lloreta, M.
Julve, New J. Chem. (2005) 210.
[7] A.T. Çolak, O.Z. Yesßilel, O. Büyükgungor, Polyhedron 29 (2010) 2127.
[8] M. Shukla, N. Srivastava, S. Saha, T.R. Rao, S. Sunkari, Polyhedron 30 (2011)
754.
[9] L. Wiehl, G. Kiel, C.P. Kohler, H. Spiering, P. Giitlich, Inorg. Chem. 25 (1986)
1565.
We investigated the synthesis and X-ray crystallographic struc-
tures of [LnPdCl2] (Ln = L1–L6), which were prepared through the
substitution reaction of [Pd(CH3CN)2Cl2] with the corresponding
N0-substituted pyridylmethylamine ligands. The co-ordination
geometry around the Pd(II) centres in complexes was square-pla-
nar. The catalytic activity of complex [L4PdCl2] toward MMA poly-
merisation in the presence of MMAO resulted in very high activity
of 1.41 ꢀ 105 g PMMA/mol Pdꢁh at 60 °C and moderate syndiotac-
ticity of ca. 70%. The catalytic activity of these Pd(II) complexes
was not affected by steric hindrance around the palladium metal
centre in complexes.
[10] L. Rong-Guang, T. Zhu, X. Sai-Feng, Z. Qian-Jiang, W.G. Jackson, W. Zhan-Bing,
L. La-Sheng, Polyhedron 22 (2003) 3467.
[11] L.P. Battaglia, M.B. Ferrari, A.B. Corradi, G.G. Fava, C. Pelizzi, M.E.V. Tani, J.
Chem. Soc., Dalton Trans. (1976) 2107.
Acknowledgments
[12] M. Hostettler, K.W. To’rnroos, D. Chernyshov, B. Vangdal, H.-B. Bu’rgi, Angew.
Chem. Int. Ed. 43 (2004) 4589.
[13] J.A. Driscoll, M.M. Allard, L. Wu, M.J. Heeg, S.R.P. da Rocha, C.N. Verani, Chem.
Eur. J. 14 (2008) 9665.
[14] K. Abdur-Rashid, R. Abbel, A. Hadzovic, A.J. Lough, R.H. Morris, Inorg. Chem. 44
(2005) 2483.
This research was supported by the National Research Founda-
tion of Korea (NRF), funded by the Ministry of the Education,
Science, and Technology (MEST) (Grant No. 2012-R1A2A2
A01045730).

74
S. Kim et al. / Polyhedron 77 (2014) 66–74
[15] V.C. Gibson, R.K. O’Reilly, D.F. Wass, A.J.P. White, D.J. Williams, Dalton Trans.
(2003) 2824.
[16] J. Gómez, G. García-Herbosa, J.V. Cuevas, A. Arnáiz, A. Carbayo, A. Muñoz, L.
Falvello, P.E. Fanwick, Inorg. Chem. 45 (2006) 2483.
[17] S.K. Kang, H.W. Lee, N. Sengottuvelan, Y.-I. Kim, Bull. Korean Chem. Soc. 33
(2012) 95.
[18] P. Maslak, J.J.J. Sczepanski, M. Parvez, J. Am. Chem. Soc. 213 (1991) 1062.
[19] A. Mondal, S. Sarkar, D. Chopra, T.N.G. Row, K.K. Rajak, Dalton Trans. (2004)
3244.
[49] D. Schweinfurth, R. Pattacini, S. Strobel, B. Sarkar, Dalton Trans. (2009) 9291.
[50] E.T.J. Strong, S.A. Cardile, A.L. Brazeau, M.C. Jennings, R. McDonald, N.D. Jones,
Inorg. Chem. 47 (2008) 10575.
[51] T.S. Billson, J.D. Crane, D. Foster, C.S.L. Russell, E. Sinn, S.J. Teat, N.A. Young,
Inorg. Chem. Commun. 2 (1999) 476.
[52] S. Iwatsuki, T. Suzuki, T. Yajima, T. Shiraiwa, O. Yamauchi, Y. Shimazaki, Inorg.
Chim. Acta 377 (2011) 111.
[53] G. Brancatelli, M. Saporita, D. Drommi, F. Nicolò, F. Faraone, J. Organomet.
Chem. 692 (2007) 5598.
[20] J.-X. Li, Y.-M. Jiang, B.-R. Lian, J. Chem. Crystallogr. 38 (2008) 711.
[21] Y.-L. Wong, J.-F. Ma, F. Xue, T.C.W. Mak, D.K.P. Ng, Organometallics 18 (1999)
5075.
[54] V. Terrasson, D. Prim, J. Marrot, Eur. J. Inorg. Chem. (2008) 2739.
[55] K. Fiore, G. Martelli, M. Monari, D. Savoia, Tetrahedron: Asymmetry 10 (1999)
4803.
[22] M.J. Robertson, G.A. Lawrance, M. Maeder, P. Turner, Aust. J. Chem. 57 (2004)
483.
[56] M.N. Kopylovich, J. Lasri, M.F.C. Guedes da Silvaa, A.J.L. Pombeiro, Dalton Trans.
(2009) 3074.
[23] S.J.A. Guieu, A. Mari, M. Lanfredi, C. Massera, L.D. Pachón, P. Gamez, J. Reedijk,
Catal. Today 96 (2004) 259.
[57] M. Zhang, M. Inamo, M. Kojima, K. Nakajima, Inorg. Chim. Acta 360 (2007)
3040.
[24] M.K. Panda, M.M. Shaikh, R.J. Butcher, P. Ghosh, Inorg. Chim. Acta 372 (2011)
145.
[58] H. Chen, J.A. Sweet, K.-C. Lam, A.L. Rheingold, D.V. McGrath, Tetrahedron
Asymmetry 20 (2009) 1672.
[25] R. Singh, A. Banerjee, K.K. Rajak, Inorg. Chim. Acta 363 (2010) 3131.
[26] R. Alberto, R. Schibli, A.P. Schubiger, J. Am. Chem. Soc. 121 (1999) 6076.
[27] X. Wang, J.D. Ranford, J.J. Vittal, J. Mol. Struct. 796 (2006) 28.
[28] A. Raja, V. Rajendiran, P.U. Maheswari, R. Balamurugan, C.A. Kilner, M.A.
Halcrow, M. Palaniandavar, J. Inorg. Biochem. 99 (2005) 1717.
[29] R. Cowdell, C.J. Davies, S.J. Hilton, J.-D. Maréchal, G.A. Solan, O. Thomas, J.
Fawcett, Dalton Trans. (2004) 3231.
[30] S. Bruda, M.M. Turnbull, C.P. Landee, Q. Xu, Inorg. Chim. Acta 359 (2006) 298.
[31] T. Chattopadhyay, N. Podder, K.S. Banu, A. Banerjee, Manami Ghosh, E. Suresh,
M. Nethaji, D. Das, J. Mol. Struct. 839 (2007) 69.
[59] V.P. Munk, C.I. Diakos, L.T. Ellis, R.R. Fenton, B.A. Messerle, T.W. Hambley,
Inorg. Chem. 42 (2003) 3582.
[60] F.-Z. Yang, Y.-H. Wang, M.-C. Chang, K.-H. Yu, S.-L. Huang, Y.-H. Liu, Y. Wang,
S.-T. Liu, J.-T. Chen, Inorg. Chem. 48 (2009) 7639.
[61] X. He, Y. Yao, X. Luo, J. Zhang, Y. Liu, L. Zhang, Q. Wu, Organometallics 22
(2003) 4952.
[62] B.K. Bahuleyan, D. Chandran, C.H. Kwak, C.-S. Ha, I. Kim, Macromol. Res. 18
(2008) 745.
[63] B. Lian, C.M. Thomas, O.L. Casagrande Jr., C.W. Lehmann, T. Roisnel, J.-F.
Carpentier, Inorg. Chem. 46 (2007) 328.
[32] S. Tanase, M. Ferbinteanu, M. Andruh, C. Mathonière, I. Strenger, G. Rombaut,
Polyhedron 19 (2000) 1967.
[33] A. Malassa, H. Görls, M. Westerhausen, Inorg. Chem. Commun. 11 (2008) 612.
[34] J.-X. Li, Y.-M. Jiang, M.-J. Chen, J. Coord. Chem. 61 (2008) 1765.
[35] H.-W. Kuai, X.-C.h. Cheng, L.-D. Feng, X.-H. Zhu, Z. Anorg. Allg. Chem. 637
(2011) 1560.
[64] J. Li, H. Song, C. Cui, Appl. Organomet. Chem. 24 (2010) 82.
[65] W. Wang, P.A. Stenson, A. Marin-Becerra, J. McMaster, M. Schroder, D.J. Irvine,
D. Freeman, S.M. Howdle, Macromolecules 37 (2004) 6667.
[66] M. Yang, W.J. Park, K.B. Yoon, J.H. Jeong, H. Lee, Inorg. Chem. Commun. 14
(2011) 189.
[67] Z. Zhang, D. Cui, A.A. Trifonov, Eur. J. Inorg. Chem. (2010) 2861.
[68] C. Lansalot-Matras, F. Bonnette, E. Mignard, O. Lavastre, J. Organomet. Chem.
693 (2008) 393.
[36] F.D. Lesh, S.S. Hindo, M.J. Heeg, M.M. Allard, P. Jain, B. Peng, L. Hryhorczuk, C.N.
Verani, Eur. J. Inorg. Chem. (2009) 345.
[37] S.K. Dey, N. Mondal, M.S.E. Fallah, R. Vicente, A. Escuer, X. Solans, M. Font-
Bardía, T. Matsushita, J.V. Gramlich, S. Mitra, Inorg. Chem. 43 (2004) 2427.
[38] P. Ai, L. Chen, Y. Guo, S. Jie, B.-G. Li, J. Organomet. Chem. 705 (2012) 51.
[39] Y.-C. Lin, K.-H. Yu, S.-L. Huang, Y.-H. Liu, Y. Wang, S.-T. Liu, J.-T. Chen, Dalton
Trans. (2009) 9058.
[69] E. Kim, H.Y. Woo, S. Kim, H. Lee, D. Kim, H. Lee, Polyhedron 42 (2012) 135.
[70] D. Kim, S. Kim, E. Kim, H.-J. Lee, H. Lee, Polyhedron 63 (2013) 139.
[71] S. Kim, E. Kim, H.-J. Lee, H. Lee, Polyhedron 69 (2014) 149.
[72] W. Massa, S. Dehghanpour, K. Jahani, Inorg. Chim. Acta 362 (2009) 2872.
[73] B.B. Wayland, R.F. Schrammz, Inorg. Chem. 8 (1969) 971.
[74] R.A. Walton, Can. J. Chem. 46 (1968) 2347.
ˇ
´
´
[40] M. Juribašic´, K. Molcanov, B. Kojic-Prodic, L. Bellotto, M. Kralj, F. Zani, L. Tušek-
ˇ ´
Bozic, J. Inorg. Biochem. 105 (2011) 867.
[75] SMART and SAINT-PLUS v 6.22, Bruker AXS Inc., Madison, Wisconsin, USA, 2000.
[76] G. M. Sheldrick, SADABS v 2.03, University of Göttingen, Germany, 2002.
[77] SHELXTL v 6.10; Bruker AXS Inc, Madison, Wisconsin, USA, 2000.
[78] R. Chûjô, K. Hatada, R. Kitamaru, T. Kitayama, H. Sato, Y. Tanaka, Polym. J. 19
(1987) 413.
[41] F. Ferioli, C. Fiorelli, G. Martelli, M. Monari, D. Savoia, P. Tobaldin, Eur. J. Org.
Chem. (2005) 1416.
[42] D. Savoia, G. Alvaro, R. Di Fabio, C. Fiorelli, A. Gualandi, M. Monari, F.
Piccinellia, Adv. Synth. Catal. 348 (2006) 1883.
[43] V. Diez, J.V. Cuevas, G. García-Herbosa, G. Aullón, J.P.H. Charmant, A. Carbayo,
A. Muñoz, Inorg. Chem. 46 (2007) 568.
[79] I.A. Opeida, M.A. Kompanets, O.V. Kushch, E.S. Papayanina, Theor. Exp. Chem.
47 (2011) 30.
[44] M.B. Smith, A.M.Z. Slawin, Polyhedron 19 (2000) 695.
[45] T. AI Allaf, P. Castan, R. Turpin, S. Wimmer, G. Bernardinelli, Transition Met.
Chem. 17 (1992) 579.
[46] J.V. Cuevas, G. García-Herbosa, A. Muñoz, S. García-Granda, D. Miguel,
Organometallics 16 (1997) 2220.
[80] T. Kitaura, T. Kitayama, Macromol. Rapid Commun. 28 (2007) 1889.
[81] Y.-J. Hu, H.H. Zou, M.-H. Zeng, N.S. Weng, J. Organomet. Chem. 694 (2009) 366.
[82] C. Carlini, M. Martinelli, E. Passaglia, A.M.R. Galletti, G. Sbrana, Macromol.
Rapid Commun. 22 (2001) 664.
[83] G. Tang, G.-X. Jin, Dalton Trans. (2007) 3840.
[47] M.W. Davies, A.J. Clarke, G.J. Clarkson, M. Shipman, J.H.R. Tucker, Chem.
Commun. (2007) 5078.
[48] S.A. Cardile, M.C. Jennings, N.D. Jones, Dalton Trans. (2006) 4672.
[84] Y.-B. Huang, G.-R. Tang, G.-Y. Jin, G.-X. Jin, Organometallics 27 (2008) 259.
[85] T.V. Laine, U. Piironen, K. Lappalainen, M. Klinga, E. Aitola, M. Leskela, J.
Organomet. Chem. 606 (2000) 112.