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Preparation and structures of a series of phosphorus-free Nickel(II) diamine complexes and their applications in hydrogenation of acetophenone.

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Full Paper
Received: 4 January 2010
Revised: 26 February 2010
Accepted: 13 March 2010
Published online in Wiley Interscience: 22 April 2010
(www.interscience.com) DOI 10.1002/aoc.1656
Preparation and structures of a series
of phosphorus-free Nickel(II) diamine
complexes and their applications
in hydrogenation of acetophenone
Zilu Chen∗, Mulan Zeng, Yuzhen Zhang, Zhong Zhang and Fupei Liang
To develop economical and phosphorus-free catalysts for hydrogenation of ketones, three new complexes, [Ni(1R,2Rdpen)2 (H2 O)Cl]2 Cl2 · 2Et2 O (1), [Ni(1R,2R-dpen)(phen)(CH3 OH)2 ]Cl2 ·2CH3 OH (2) and [Ni(1,8-dan)2 (DMF)Cl]2 Cl2 · 3H2 O (3), and
three reported compounds, [Ni(opda)(phen)Cl2 ]·CH3 OH (4), [Ni(opda)2 Cl2 ] (5) and [Ni(1,2-dach)2 ]Cl2 (6), were prepared
and the structures of new compounds were determined by single crystal X-ray diffraction analysis, in which 1R,2R-dpen,
phen, 1,8-dan, opda and 1,2-dach denote 1R,2R-1,2-diphenylethylenediamine, 1,10-phenanthroline, 1,8-diaminonaphthalene,
o-phenylenediamine and 1,2-diaminocyclohexane, respectively. The catalytic effects for hydrogenation of acetophenone of
these compounds were tested. This revealed very poor or no catalytic effects of these complexes in transfer hydrogenation of
acetophenone using isopropanol or HCOOH–NEt3 as hydrogen source. However, they presented much better catalytic effects
in ionic hydrogenation of acetophenone using H2 gas as hydrogen source with a dependence of the catalytic effects on the base
used in the hydrogenation reactions. The complexes represent a kind of green hydrogenation catalyst, although the conversion
c 2010 John Wiley & Sons, Ltd.
in the hydrogenation reactions is not as high as expected. Copyright Keywords: nickel(II) diamine complexes; hydrogenation; acetophenone; crystal structure; catalytic
Introduction
Appl. Organometal. Chem. 2010, 24, 625–630
Scheme 1. A schematic view of six Ni(II)-diamine complexes used for
catalyzed hydrogenation of acetophenone.
diamine complexes (Scheme 1), in which the structures of the three
new compounds were determined. Their application as catalysts
in hydrogenation of acetophenone was investigated.
∗
Correspondence to: Zilu Chen, School of Chemistry and Chemical Engineering,
Guangxi Normal University, Yucai Road 15, Guilin, 541004, People’s Republic of
China. E-mail: chenziluczl@yahoo.co.uk
School of Chemistry and Chemical Engineering, Guangxi Normal University,
Yucai Road 15, Guilin, 541004, People’s Republic of China
c 2010 John Wiley & Sons, Ltd.
Copyright 625
Catalysts for hydrogenation of ketones, imines or carbonylcontaining compounds have undergone rapid development in
recent decades.[1 – 11] Among them, Noyori-type bifunctional catalysts for ionic hydrogenation exhibit high catalytic efficiency due
to their outer-sphere mechanism.[1,12] However, the presence of
phosphorus in Noyori-type bifunctional catalysts limits their application from the point of view of environmental protection.
Thus it is highly desirable to develop phosphorus-free hydrogenation catalysts for practical application.[13,14] Bearing in mind
the need for environmental protection and the high efficiency of
Noyori-type bifunctional hydrogenation catalysts, we took up the
challenge to develop green catalysts free from phosphorus. Most
of the recently developed hydrogenation catalysts are complexes
of precious metals such as Ru, Rh and Ir. Nevertheless, several
studies have revealed that the early transition metal complexes
can also act as hydrogenation catalysts for unsaturated organic
molecules.[15 – 17] For economic reasons we attempted to use
cheap metals to replace the expensive metals. Thus we prepared
some transition metal complexes bearing diamine ligands in the
presence or absence of ancillary ligands to tune the electronic
density within the complexes. In our design, the coordinating
atoms from diamine ligands and the main ancillary ligands were
expected to occupy the equatorial positions of the metal, and
the axial sites were left for chloro atoms or some weakly bonded
ligands, or just for vacant sites. This kind of complex might achieve
the purpose of hydrogenation of ketones via a mechanism similar to that of Noyori’s catalysts. Herein we present the synthesis
of three reported Ni(II) diamine complexes and three new Ni(II)
Z. Chen et al.
Experimental
General Procedures
All chemicals were used as obtained without further purification.
Infrared spectra were recorded as KBr pellets using a Nicolet
360 FT-IR spectrometer. Elemental analyses (C, H and N) were
performed on a Vario EL analyzer. The hydrogenation products
were analyzed by a gas chromatograph GC-14B equipped with a
PEG-2M column.
Synthesis of [Ni(1R,2R-dpen)2 (H2 O)Cl]2 Cl2 ·2Et2 O (1)
NiCl2 ·6H2 O (0.2380 g, 1 mmol) was heated to 453 K overnight to
remove water. The obtained yellow powder NiCl2 was dissolved in
ethanol. To this solution an ethanol solution (4 ml) of (1R,2R)-1,2diphenylethylenediamine (0.2130 g, 1 mmol) was added dropwise.
An ethanol solution (5 ml) of 2,2 -bipyridine (0.1580 g, 1 mmol)
was added to the resulted solution after stirring for 2 h. The
solution was further stirred at room temperature for 24 h and
filtered subsequently. The diffusion of diethyl ether into the
filtrate for 1 week gave blue crystals in a yield of 49%. Anal.
calcd for C32 H44 Cl2 N4 NiO2 (646.32): C, 59.47; H, 6.86; N, 8.67.
Found: C, 59.09; H, 6.81; N, 8.94. IR (KBr, cm−1 ): 3213(s), 3137(s),
1599(s), 1495(m), 1476(m), 1098(m), 1442(s), 1158(m), 1010(s),
768(s), 773(m), 698(m), 565(w).
Synthesis of [Ni(1R,2R-dpen)(phen)(CH3 OH)2 ]Cl2 ·2CH3 OH (2)
A mixture of NiCl2 ·6H2 O (0.2380 g, 1 mmol), (1R,2R)-1,2-diphenylethylenediamine (0.2130 g, 1 mmol), 1,10-phenanthroline
(0.1980 g, 1 mmol) and ethanol (12 ml) was sealed in a 25 ml
Teflon-lined autoclave and heated at 413 K for 3 days. Then the
autoclave was slowly cooled to room temperature, giving green
microcrystals. Single crystals of 2 for X-ray diffraction analysis
were obtained by the diffusion of diethyl ether into a methanol
solution of the green microcrystals for 1 week in a yield of 30%.
Anal. calcd for C30 H40 Cl2 N4 NiO4 (650.27): C, 55.41; H, 6.20; N, 8.62.
Found: C, 55.76; H, 6.56; N, 8.35. IR (KBr, cm−1 ): 3313(s), 3252(s),
1587(m), 1517(m), 1496(m), 1454(w), 1426(m), 1017(s), 849(m),
768(m), 726(m), 700(m), 564(w).
Synthesis of [Ni2 (1,8-dan)4 (DMF)2 Cl2 ]Cl2 ·3H2 O (3)
An ethanol and acetonitrile solution of NiCl2 ·6H2 O (0.238 g,
1 mmol) was added dropwise into an acetonitrile solution of
1,8-diaminonaphthalene (0.3180 g; 2 mmol). The resulted mixture
was stirred at ambient temperature for 5 h. The red precipitate
formed was collected by filtration, washed with ethanol (3 ml ×
3) and dissolved in mixed solvent of methanol and DMF after
dryness. The diffusion of diethyl ether into the resulting solution
for 8 days gave brown needle crystals in a yield of 51%. Anal. calcd
for C46 H60 Cl4 N10 Ni2 O5 (1092.26): C, 50.58; H, 5.54; N, 12.82. Found:
C, 50.86; H, 5.85; N, 12.63. IR (KBr, cm−1 ): 3226(s), 3128(s), 1654(s),
1618(m), 1584(m), 1402(m), 1281(m), 1114(m),1094(m), 1003(m),
823(m), 766(m).
General Procedure for the Catalytic Hydrogenation
626
The samples for hydrogenation of acetophenone using H2 as
hydrogen source were prepared as follows: the Ni(II) complex
(0.02 mmol), acetopheneone (20 mmol), 5 ml of isopropanol and
KOH (2 mmol) or t BuOK (2 mmol) were added into a hydrogenation
www.interscience.wiley.com/journal/aoc
vessel. The vessel was purged with hydrogen gas and pressurized
to 50 atm. Then the sealed vessel was heated at 80 ◦ C for 5 h.
After releasing the pressure, the reaction mixture was filtered
through a short silica gel column. For the transfer hydrogenation
of acetophenone using isopropanol as hydrogen source, the
Ni(II) complex (0.02 mmol), acetopheneone (2 mmol), 5 ml of
isopropanol and KOH (0.2 mmol) or t BuOK (0.2 mmol) were placed
in a Young–Schlenk apparatus and heated at 50 ◦ C for 5 h. The
reaction mixture was filtered through a short silica gel column
after being cooled to ambient temperature. The samples for
transfer hydrogenation using HCOOH–NEt3 as hydrogen source
were prepared in a way similar to that for transfer hydrogenation
of acetophenone using isopropanol as hydrogen source, except
that the hydrogen source was changed to HCOOH–NEt3 . The
filtrates were analyzed by gas chromatography using a PEG-2M
column; carrier gas, N2 (flow 30 ml min−1 ); injection temp, 200 ◦ C;
initial column temperature, 150 ◦ C; progress rate, 1 ◦ C min−1 ; final
column temperature, 190 ◦ C.
X-Ray Crystallography
The selected single crystals of 1, 2 and 3 were put in a sealed
tube and the measurement was performed on a Bruker Smart
Apex-II CCD diffractometer using graphite-monochromated Mo
Kα radiation (λ = 0.71073 Å). Absorption correction was applied
using the multi-scan program SADABS.[18] All of the structures were
solved by direct methods using the Program SHELXS-97[19] and
refined by full-matrix least-squares methods on all F2 data with
SHELXL-97.[20] The program PLATON[21] was used to check the
result of the X-ray analysis and the program ORTEP[22] was used
to give a representation of the structures. H atoms were placed in
the calculated positions on C atoms. Experimental details for the
structure analysis of 1, 2 and 3 are given in Table 1. The selected
bond distances and angles for 1, 2 and 3 are listed in Table 2.
CCDC 760105, 760106 and 760107 for complexes 1–3,
respectively, contain the supplementary crystallographic 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.
Results and Discussion
Synthesis
The synthetic studies revealed that the removal of water molecules
from NiCl2 ·6H2 O is very important for the preparation of 1. The
hydrothermal synthesis of 2 depends on the reaction temperature
and reaction methods. Compound 2 was obtained by the diffusion
of diethyl ether into the methanol solution of the product
separated from the hydrothermal reaction of NiCl2 ·6H2 O with
(1R,2R)-1,2-diphenylethylenediamine and 1,10-phenanthroline at
140 ◦ C. The similar hydrothermal reaction at 100 ◦ C failed to
give 2. An alternative reaction of NiCl2 ·6H2 O with (1R,2R)-1,2diphenylethylenediamine and 1,10-phenanthroline in ethanol
at 80 ◦ C by routine solution method failed also to produce
2. Complexes 4–6 were prepared according to the literature
methods.[23 – 26]
Crystal Structures of 1–3
The single crystal X-ray diffraction analysis reveals two [Ni(1R,2Rdpen)2 (H2 O)Cl]+ cations, two chloride anions and two diethyl
c 2010 John Wiley & Sons, Ltd.
Copyright Appl. Organometal. Chem. 2010, 24, 625–630
A series of phosphorus-free nickel(II) diamine complexes
Table 1. Crystal data and structure refinement parameters for compounds 1–3
Formula
fw
T (K)
λ (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
α (deg)
β (deg)
γ (deg)
V (Å 3 )
Z
Dc (g cm−3 )
µ (mm−1 )
F(000)
Crystal size (mm)
θ (deg)
Reflections collected/unique
Rint
GOF on F 2
R1 [I > 2σ (I)]a
wR2 [I > 2σ (I)]b
R1 (all data)a
wR2 (all data)b
Flack
Largest diff. peak and hole (e ·Å −3 )
a
b
1
2
3
C32 H44 Cl2 N4 NiO2
646.32
293(2)
0.71073
Triclinic
P1
9.738(7)
10.439(8)
16.418(12)
105.044(11)
98.591(10)
90.003(11)
1592(2)
2
1.348
0.812
684
0.29 × 0.27 × 0.15
2.02–25.01
7512/6217
0.0614
0.984
0.0878
0.1990
0.1447
0.2395
0.08(4)
1.213 and −0.622
C30 H40 Cl2 N4 NiO4
650.27
298(2) K
0.71073
Monoclinic
C2/c
10.129(2)
17.184(4)
18.051(4)
90
94.734(4)
90
3131.2(12)
4
1.379
0.831
1368
0.45 × 0.41 × 0.39
2.26–25.06
8099/2769
0.0344
1.054
0.0405
0.0894
0.0646
0.1026
C46 H60 Cl4 N10 Ni2 O5
1092.26
273(2) K
0.71073
Monoclinic
P21 /c
15.0758(10)
22.7726(15)
16.3817(11)
90
113.3880(10)
90
5162.0(6)
4
1.405
0.990
2280
0.30 × 0.30 × 0.20
2.24–25.00
26439/9076
0.0230
1.034
0.0419
0.1227
0.0545
0.1327
0.659 and −0.247
0.770 and −0.637
R1 = Fo | − |Fc /|Fo |;
wR2 = [w(F o 2 − F c 2 )2 /w(F o 2 )2 ]1/2 .
Figure 2. ORTEP plot of 2. Hydrogen atoms are omitted for clarity. The
displacement ellipsoids are drawn with 30% probability.
Figure 1. ORTEP plot of 1. Solvate molecules and hydrogen atoms are
omitted for clarity. The displacement ellipsoids are drawn with 30%
probability.
Appl. Organometal. Chem. 2010, 24, 625–630
c 2010 John Wiley & Sons, Ltd.
Copyright www.interscience.wiley.com/journal/aoc
627
ether molecules in one asymmetric unit of 1 (Fig. 1). Both Ni(II)
ions in the two [Ni(1R,2R-dpen)2 (H2 O)Cl]+ cations are coordinated
by one chloro atom and one water molecule in axial sites and
four nitrogen atoms from two 1R,2R-dpen ligands in equatorial
positions to form a distorted octahedral geometry. As shown
in Table 2, the corresponding bond lengths and bond angles
show some difference in the two [Ni(1R,2R-dpen)2 (H2 O)Cl]+
cations. For example, the largest Ni–N bond lengths in both
coordination units are 2.149(14) Å and 2.114(13) Å, respectively.
The Ni–N bond lengths are comparable to those reported in
related compounds.[27 – 31]
Crystals of 2 suitable for X-ray diffraction analysis were
obtained by diffusion of diethyl ether into a methanol solution
of the product separated from the hydrothermal reaction of
NiCl2 ·6H2 O with (1R,2R)-1,2-diphenylethylenediamine and 1,10phenanthroline at 140 ◦ C. It was shown there are one [Ni(1R,2Rdpen)(phen)(CH3 OH)2 ]2+ cation, two chloride anions and two
solvate methanol molecules in the asymmetric unit of 2 (Fig. 2).
Z. Chen et al.
Table 2. Selected bond lengths (Å) and angles (deg) for 1–3
Complex 1
Ni1–N3
Ni1–N1
Ni1–N4
Ni1–O1
N3–Ni1–N1
N3–Ni1–N4
N1–Ni1–N4
N3–Ni1–O1
N1–Ni1–O1
N4–Ni1–O1
N3–Ni1–N2
N1–Ni1–N2
N4–Ni1–N2
O1–Ni1–N2
2.149(14)
2.488(5)
2.040(15)
2.049(12)
95.6(4)
91.0(4)
91.2(4)
176.5(4)
88.9(4)
99.8(5)
176.6(5)
83.6(5)
81.1(5)
171.7(6)
Ni2–N8
Ni2–N6
Ni2–O2
Ni2–Cl2
N8–Ni2–N6
N5–Ni2–O2
N7–Ni2–O2
N8–Ni2–O2
N6–Ni2–O2
N5–Ni2–Cl2
N7–Ni2–Cl2
N8–Ni2–Cl2
N6–Ni2–Cl2
O2–Ni2–Cl2
2.079(11)
2.114(13)
2.136(13)
2.470(5)
95.6(4)
93.4(5)
84.1(5)
87.4(5)
87.6(5)
90.0(4)
93.2(4)
89.3(4)
95.1(4)
176.0(4)
Complex 2
Ni1–N1
2.076(2)
Ni1–N2
2.083(2)
N1A–Ni1–N1
83.38(12)
N2–Ni1–N2A
80.41(13)
N1A–Ni1–N2
178.51(9)
N1A–Ni1–O1A
88.96(9)
N1–Ni1–N2
98.11(9)
N1–Ni1–O1A
89.71(10)
N1A–Ni1–N2A
98.11(9)
N2–Ni1–O1A
91.14(9)
N1–Ni1–N2A
178.51(9)
N2A–Ni1–O1A
90.22(10)
Symmetry transformations used to generate equivalent atoms: (A)−x + 1, y, −z + 1/2
Ni1–O1
N1A–Ni1–O1
N1–Ni1–O1
N2–Ni1–O1
N2A–Ni1–O1
O1A–Ni1–O1
2.100(2)
89.71(10)
88.96(9)
90.22(10)
91.14(9)
178.22(14)
Ni2–N6
Ni2–N8
Ni2–N9
Ni2–Cl2
N6–Ni2–N8
O2–Ni2–N9
N7–Ni2–N9
N6–Ni2–N9
N8–Ni2–N9
O2–Ni2–Cl2
N7–Ni2–Cl2
N6–Ni2–Cl2
N8–Ni2–Cl2
N9–Ni2–Cl2
2.092(3)
2.098(3)
2.108(2)
2.5111(9)
174.53(10)
94.48(10)
174.20(11)
99.39(10)
80.07(10)
176.46(7)
85.89(8)
85.10(8)
89.44(8)
88.95(8)
Complex 3
Ni1–O1
Ni1–N2
Ni1–N3
Ni1–N1
O1–Ni1–N2
O1–Ni1–N3
N2–Ni1–N3
O1–Ni1–N1
N2–Ni1–N1
N3–Ni1–N1
O1–Ni1–N4
N2–Ni1–N4
N3–Ni1–N4
N1–Ni1–N4
2.059(14)
2.062(12)
2.067(13)
2.128(11)
95.5(5)
83.4(5)
177.6(6)
87.7(5)
87.6(5)
90.3(5)
175.1(6)
82.8(5)
98.2(5)
87.7(5)
2.061(2)
2.070(2)
2.092(3)
2.097(3)
92.68(10)
91.24(10)
95.01(10)
91.28(10)
83.28(10)
177.02(11)
94.03(10)
172.08(11)
80.65(10)
100.75(10)
Ni1–N2
Ni1–Cl1
Ni2–N5
Ni2–N7
N3–Ni1–Cl1
N1–Ni1–Cl1
N4–Ni1–Cl1
O1–Ni1–Cl1
N2–Ni1–Cl1
N5–Ni2–N7
N5–Ni2–N8
N7–Ni2–N8
N5–Ni2–N6
N7–Ni2–N6
Ni1–N4
Ni1–Cl1
Ni2–O2
Ni2–N7
O1–Ni1–Cl1
N2–Ni1–Cl1
N3–Ni1–Cl1
N1–Ni1–Cl1
N4–Ni1–Cl1
O2–Ni2–N7
O2–Ni2–N6
N7–Ni2–N6
O2–Ni2–N8
N7–Ni2–N8
628
The Ni(II) ion in 2 possesses a slightly distorted octahedral
geometry with four coordinated nitrogen atoms from one
1,10-phenanthroline molecule and one 1R,2R-dpen molecule
in equatorial plane and two methanol molecules in the axial
positions. The Ni–N and Ni–O bond lengths (Table 2) are
comparable to those in 1 and the corresponding reported
compounds.[30,31]
Crystals of 3 suitable for X-ray diffraction analysis were obtained
by diffusion of diethyl ether into a methanol and DMF solution of
3 for 8 days at ambient temperature. The X-ray diffraction analysis
reveals two [Ni(1,8-dan)2 (DMF)Cl]+ cations, two chloride anions
and three solvate water molecules in the asymmetric unit of 3
(Fig. 3). One of the water molecules was refined disordered. The
two [Ni(1,8-dan)2 (DMF)Cl]+ cations show some similarities with
distorted octahedral geometry around the Ni(II) center completed
by four nitrogen atoms from two 1,8-dan molecules in the
equatorial positions and one chloro atom and one DMF molecule
at the axial positions. The two naphthalene groups point towards
the same half sphere where the coordinated DMF molecule is
www.interscience.wiley.com/journal/aoc
2.105(3)
2.5343(10)
2.060(2)
2.078(2)
177.38(7)
86.25(8)
91.23(8)
86.22(8)
87.22(8)
90.73(10)
93.46(10)
82.83(10)
92.01(10)
97.21(10)
Figure 3. ORTEP plot of 3. Solvate water molecules are omitted. The
displacement ellipsoids are drawn with 30% probability.
c 2010 John Wiley & Sons, Ltd.
Copyright Appl. Organometal. Chem. 2010, 24, 625–630
A series of phosphorus-free nickel(II) diamine complexes
Table 3. Transfer hydrogenation of acetophenone catalyzed by complexes 1–6 in the presence of base with isopropanol as hydrogen source
Entry
1
2
3
4
5
6
Ni(II)
complex
1
2
3
4
5
6
Base
Conversion (%)
KOH
KOH
KOH
KOH
KOH
KOH
2.8
3.9
3.6
0.5
4.3
0
TON
2.8
3.9
3.6
0.5
4.3
0
Entry
Ni(II)
complex
7
8
9
10
11
12
1
2
3
4
5
6
Base
Conversion (%)
TON
t BuOK
2.4
5.4
3.5
2.9
3.4
0
2.4
5.4
3.5
2.9
3.4
0
t
BuOK
t BuOK
t BuOK
t BuOK
t BuOK
Ni(II) complex : base : acetophenone = 1 : 10 : 100; solvent, isopropanol; reaction temperature, 50 ◦ C.
Table 4. Hydrogenation of acetophenone catalyzed by complexes 1–6 in the presence of base with H2 gas as hydrogen source
Entry
1
2
3
4
5
6
Ni(II)
complex
Base
Conversion (%)
TON
Entry
Ni(II)
complex
1
2
3
4
5
6
KOH
KOH
KOH
KOH
KOH
KOH
18.2
43.8
72.1
2.9
56
4.2
182
438
721
29
561
42
7
8
9
10
11
12
1
2
3
4
5
6
Base
Conversion (%)
TON
t BuOK
7.6
55
34.1
2.9
58.7
4.9
76
551
341
29
587
49
t BuOK
t
BuOK
t BuOK
t BuOK
t BuOK
Ni(II) complex : base : acetophenone = 1 : 100 : 1000; solvent, isopropanol; reaction temperature, 80 ◦ C; H2 pressure, 50 atm.
located, with the other half sphere left only for the coordinated
chloro atom. The Ni–N and Ni–O bond lengths (Table 2) are
comparable to those in 1 and 2, while the Ni–Cl bond lengths are
a little shorter than those in 1.
Hydrogenation of Acetophenone Catalyzed by Complexes 1–6
Appl. Organometal. Chem. 2010, 24, 625–630
Three new complexes and three reported compounds were
prepared. The catalytic effects for transfer hydrogenation and ionic
hydrogenation of acetophenone of these compounds were tested,
revealing very poor or no catalytic effects in transfer hydrogenation
of acetophenone using isopropanol or HCOOH–NEt3 as hydrogen
sources. However, the complexes present some catalytic effects in
ionic hydrogenation of acetophenone using H2 gas as hydrogen
source with dependence of on the catalytic effects on the base
used in the hydrogenation reactions. Although the conversion in
the ionic hydrogenation reactions was not so high as expected,
these complexes do represent a kind of green hydrogenation
catalyst.
Acknowledgments
The authors acknowledge the financial support by National Natural
Science Foundation of China (grant no. 20962003) and Guangxi
Natural Science Foundation (grant no. 0991008).
References
[1] R. Noyori, T. Ohkuma, Angew. Chem. Int. Ed. 2001, 40, 40.
[2] C. Sui-Seng, F. N. Haque, A. Hadzovic, A. M. Puetz, V. Reuss,
N. Meyer, A. J. Lough, M. Z. D. Iuliis, R. H. Morris, Inorg. Chem. 2009,
48, 735.
[3] J. E. D. Martins, M. Wills, Tetrahedron 2009, 65, 5782.
[4] D. T. Hog, M. Oestreich, Eur. J. Org. Chem. 2009, 5047.
[5] R. J. Hamilton, S. H. Bergens, J. Am. Chem. Soc. 2008, 130, 11979.
[6] D. Gnanamgari,
A. Moores,
E. Rajaseelan,
R. H. Crabtree,
Organometallics 2007, 26, 1226.
[7] H. Y. Cheng, J. M. Hao, H. J. Wang, C. Y. Xi, X. C. Meng, S. X. Cai,
F. Y. Zhao, J. Mol. Catal. A: Chem. 2007, 278, 6.
[8] G. K. S. Prakash, T. Mathew, E. R. Marinez, P. M. Esteves, G. Rasul,
G. A. Olah, J. Org. Chem. 2006, 71, 3952.
c 2010 John Wiley & Sons, Ltd.
Copyright www.interscience.wiley.com/journal/aoc
629
The catalytic effects of complexes 1–6 for hydrogenation of
acetophenone were tested using H2 gas, isopropanol and
HCOOH–NEt3 as hydrogen sources, respectively. Complexes 1–6
showed very poor catalytic effects in transfer hydrogenation
of acetophenone with a turnover number (TON) of 0–5 when
isopropanol was used as hydrogen source (Table 3), and no
apparent catalytic effects were found for complexes 1–6 in
transfer hydrogenation of acetophenone when HCOOH–NEt3
was used as hydrogen source. However they showed much
better catalytic effects in ionic hydrogenation of acetophenone
using H2 gas as hydrogen source, as shown in Table 4. Table 4
reveals that the catalytic effects of complexes 1–3 in ionic
hydrogenation of acetophenone using H2 gas as hydrogen source
depend on the base used in the hydrogenation reactions. The
hydrogenation of acetophenone catalyzed by 1 and 3 in the
presence of KOH presented much higher TON than that in the
presence of t BuOK. However, the hydrogention of acetophenone
catalyzed by 2 presented the converse result. The hydrogenation of
acetophenone catalyzed by 4–6 did not show any dependence on
the base used in the reaction. In comparison to the hydrogenation
catalyst bearing phosphine ligands and expensive metals such
as ruthenium, iridium and rhodium,[32 – 34] these Ni(II) complexes
presented much poorer catalytic efficiencies. Nevertheless, they
represent a kind of green catalyst owing to the fact that these
complexes are phosphorus-free. Exploration of more efficient
green catalysts is still underway.
Conclusions
Z. Chen et al.
[9] M. T. Reetz, X. G. Li, J. Am. Chem. Soc. 2006, 128, 1044.
[10] R. M. Bullock, Chem. Eur. J. 2004, 10, 2366.
[11] T. Ohkuma, H. Takeno, Y. Honda, R. Noyori, Adv. Synth. Catal. 2001,
343, 369.
[12] R. Noyori, M. Yamakawa, S. Hashiguchi, J. Org. Chem. 2001, 66, 7931.
[13] H. Zhou, Z. Li, Z. Wang, T. Wang, L. Xu, Y. He, Q.-H. Fan, J. Pan, L. Gu,
A. S. C. Chan, Angew. Chem. Int. Ed. 2008, 47, 8464.
[14] C. Hedberg, K. Källström, P. I. Arvidsson, P. Brandt, P. G. Andersson,
J. Am. Chem. Soc. 2005, 127, 15083.
[15] P. Zerecero-Silva, I. Jimenez-Solar, M. G. Crestani, A. Arévalo,
R. Barrios-Francisco, J. J. García, Appl. Catal. A: Gen. 2009, 363, 230.
[16] A. L. Iglesias, J. J. García, J. Mol. Catal. A: Chem. 2009, 298, 51.
[17] F. Négrier, E. Marceau, M. Che, J.-M. Giraudon, L. Gengembre,
A. Löfberg, Catal. Lett. 2008, 124, 18.
[18] G. M. Sheldrick, SADABS, University of Göttingen: Göttingen, 2002.
[19] G. M. Sheldrick, SHELXS-97 Program for the Solution of Crystal
Structures, University of Göttingen: Göttingen, 1997.
[20] G. M. Sheldrick, SHELXL-97 Program for the Refinement of Crystal
Structures, University of Göttingen: Göttingen, 1997.
[21] A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7.
[22] L. J. Farrugia, J. Appl. Crystallogr. 1997, 30, 565.
[23] Z. L. Chen, Y. Z. Zhang, F. P. Liang, Acta Crystallogr. Sect. E 2006, 62,
M1296.
[24] K. R. Maxcy, R. Smith, R. D. Willett, A. Vij, Acta Crystallogr. Sect. C
2000, 56, e454.
[25] S. Garcia-Granda, M. R. Diaz, F. Gomez-Beltran, Acta Crystallogr. Sect.
C 1991, C47, 181.
[26] R. Saito, Y. Kidani, Bull. Chem. Soc. Jpn. 1978, 51, 159.
[27] J. Bubanec, J. Cernak, I. Potocnak, M. Drabik, J. Lipkowski, Chem.
Pap. 2004, 58, 224.
[28] M. Ohba, N. Maruono, H. Okawa, T. Enoki, J.-M. Latour, J. Am. Chem.
Soc. 1994, 116, 11566.
[29] A. Gleizes, A. Meyer, M. A. Hitchman, O. Kahn, Inorg. Chem. 1982, 21,
2257.
[30] Y. Wang, R. Cao, W. Bi, X. Li, X. Li, D. Sun, J. Mol. Struct. 2005, 738, 51.
[31] J. J. Fiol, A. García-Raso, A. Terrón, I. Mata, E. Molins, Inorg. Chim.
Acta 1997, 262, 85.
[32] J. H. Xie, S. Liu, W. L. Kong, W. J. Bai, X. C. Wang, L. X. Wang,
Q. L. Zhou, J. Am. Chem. Soc. 2009, 131, 4222.
[33] M. Z. D. Iuliis, R. H. Morris, J. Am. Chem. Soc. 2009, 131, 11263.
[34] B. Z. Li, J. S. Chen, Z. R. Dong, Y. Y. Li, Q. B. Li, J. X. Gao, J. Mol. Catal.
A: Chem. 2006, 258, 113.
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