Synthesis and catalytic activity of novel Ni-N complexes1

Article abstract of DOI:10.1134/S1070328412080088

A series of nickel complexes with 1,3-xylylenediamine, 1,2-diaminobenzene and 1,2-aminobenzylamine were first synthesized and characterized. The reaction of these amines with Ni(OAc)₂ · 4H₂O and NiCl ₂ · 6H₂O in methanol or tetrahydrofuran resulted in the production of four novel nickel complexes I, II, III, and IV. The structure of each complex was determined by X-ray diffraction analysis. Each complex was also characterized using elemental analysis, ¹H NMR and IR. The complexes were then used to catalyze the Henry reaction, and good catalytic results (65-99%) were achieved. The catalytic activity of the complexes was determined by ¹H NMR.

Full text of DOI:10.1134/S1070328412080088

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2012, Vol. 38, No. 8, pp. 567–572. © Pleiades Publishing, Ltd., 2012.
1
Synthesis and Catalytic Activity of Novel Ni–N Complexes
a, *
a
a
b
a
b
L. Mei , F. H. Tao , D. Long , Z. S. Ming , L. X. Liang , and L. Q. Rong
a
Hefei University of Technology, Department of Chemical Engineering, Hefei, 230009 P.R. China
b
University of Science and Technology, Department of Chemistry, Hefei, 230009 P.R. China
*
eꢀmail: lmhh5523385@yahoo.cn
Received March 25, 2011
Abstract—A series of nickel complexes with 1,3ꢀxylylenediamine, 1,2ꢀdiaminobenzene and 1,2ꢀ
aminobenzylamine were first synthesized and characterized. The reaction of these amines with Ni(OAc)2
4
⋅
H O and NiCl ⋅ 6H O in methanol or tetrahydrofuran resulted in the production of four novel nickel comꢀ
2 2 2
plexes I, II, III, and IV. The structure of each complex was determined by Xꢀray diffraction analysis. Each
1
complex was also characterized using elemental analysis, H NMR and IR. The complexes were then used to
catalyze the Henry reaction, and good catalytic results (65–99%) were achieved. The catalytic activity of the
complexes was determined by H NMR.
1
DOI: 10.1134/S1070328412080088
1
INTRODUCTION
rich and Fluka. Elemental analysis was carried out
with a Perkin–Elmer 2400ꢀCHN instrument. Infrared
spectra were recorded on a Mattson Galaxy Series
FTIR 3000 spectrometer.
Nickel complexes have widely been used as the catꢀ
alysts in organic reactions and polymerization [1–6].
In the metal complex catalysis, nickel has low price
and toxicity and good coordination ability. Therefore,
it is more desirable to be placed at the center of the
metal elements, and many nickelꢀbased metal comꢀ
plex catalysts have been designed and synthesized. For
example, chiral Ni(II) complex of glycine with
Synthesis of complex I. 2.6 mL of 1,3ꢀxylylenediꢀ
amine (0.02 mol) was added to 30 mL of a THF soluꢀ
tion of 1.2450 g (0.005 mol) Ni(OAc)2
100 mL Schlenk flask.The reaction mixture were reꢀ
⋅
4H O in a dry
2
fluxed for 24 h. The solvent was reduced under vacuꢀ
um. Blue solids were obtained after rotary evaporaꢀ
tion, and then recrystallized with hexane and ethanol.
(
Nꢀtransꢀenoyl)oxazolidines was used as the catalyst
in asymmetric Michael addition reactions [7]. The
Henry reaction is a classical C–C bond reaction. It is
widely used in pharmaceutical intermediates and natꢀ The blue crystals were obtained. The yield was 45%.
ural product synthesis [8]. ꢀNitro alcohol addition
product is an important intermediate in the subseꢀ For C20
β
H N O Ni
30 4 4
quent reaction by the formation of a variety of groups, anal. calcd., %: C, 53.48;
H, 6.73;
N, 12.47.
such as through oxidation of the corresponding aldeꢀ
Found, %:
C, 52.88;
H, 6.62;
N, 12.14.
hydes, ketones, or carboxylic acid and amino comꢀ
pounds by the reduction reaction. Recently, it has
been reported that the zinc and copper complexes can IR (KBr;
also catalyze the Henry reaction [9–11]. Inspired by 1025, 715, 599.
their work, our efforts have been focused on devising
new late transition metal complexes bearing simple
ancillary ligands for catalytic coꢀaddition of aldehyde
to other monomers. In this paper, we first describe the 1.1884 g (0.005 mol) of NiCl
–
1
ν
, cm ): 3248, 3166, 2962, 1599, 1347,
Synthesis of complex II. 1.0814 g (0.01mol) of 1,2ꢀ
diaminobenzene was added to 30 mL of THF, and
6H O in a dry 100 mL
⋅
2
2
synthesis of novel complexes with a simple oneꢀpot Schlenk flask. The reaction mixture was refluxed for
method, and our complexes were used to catalyze the 72 h. After hot filtration, the residue was washed with
Henry reaction.
THF first, and then dissolved in DMF. The solvents
reduced under vacuum, and the light blue crystals were
obtained. The yield was 41.3%.
EXPERIMENTAL
,2ꢀAminobenzylamine, 1,2ꢀdiaminobenzene and
,3ꢀxylylenediamine were purchased from Acros, Aldꢀ
1
For C H Cl N Ni
16
12
2
4
1
anal. calcd., %: C, 41.66;
Found, %: C, 41.46;
H, 4.66;
H, 4.52;
N, 16.20.
N, 16.09.
1
The article is published in the original.
567

568
MEI et al.
1
H NMR (300 MHz; CDCl ; 27
3
H), 6.11–6.12 (d., J
s., 4H), 2.11(s., 6H).
°
C;
, ppm): 6.93 (t., 0.986 mmol), and nitromethane (0.50 mL, 9.255 mmol)
δ
1
(
= 6.5 Hz, 2H), 6.04(s., 1H), 3.82 were successively added together at room temperature.
After 72 h, the reaction was quenched. Purification
was performed using silica gel chromatography (petroꢀ
–1
IR (KBr; ν, cm ): 3292, 3196, 3164, 3108, 1608, 1572,
1495, 1249, 1219, 1099, 1027, 942, 751, 622, 500.
leum ether–dichloromethane (v/v = 7 : 3). The title
compound was obtained as a colorless liquid in a 50%
Synthesis of complex III. 0.6109 g (0.005 mol) of
,2ꢀaminobenzylamine was added to 30 mL of THF,
0.6221 g, 0.0025 mol) Ni(OAc)2 · 4H O in a dry
2
00 mL Schlenk flask. The reaction mixture was reꢀ
1
yield of compound V. H NMR (300 MHz; CDCl )
3
1
(
7.187.23 (m., 2H, Ar
⎯H), 7.29–7.43 (m., 3H, Ar–H),
4.73–4.78 (m., 3H), 4.26–4.30 (m., 1H).
1
fluxed for 72 h. After hot filtration, the residue was reꢀ
Synthesis of (Ε) ꢀnitrostyrene radical anion (VI).
ꢀβ
crystallized with CH Cl and hexane, and the blue Following the procedure describing the synthesis of V.
2
2
1
crystals were obtained. The yield was 35.8%.
H NMR (300 MHz; CDCl ) 8.00 (d.,
7
J
.47–7.63 (m., 6H). The yield was 40%.
= 23Hz, 1H),
3
For C H N O Ni
4 8
18
34
Xꢀray structure determination. Crystal of complexꢀ
II III, and IV were chosen and mounted on a
anal. calcd., %: C, 43.83;
Found, %: C, 43.77;
H, 6.94;
H, 6.82;
N, 11.36.
N, 11.09.
es
I,
,
SMART 1000 CCD diffractometer. The data were colꢀ
lected with graphiteꢀmonochromated Mo radiation
K
α
–1
IR (KBr; ν, cm ): 3341, 3238, 3040, 2887, 2326, 1554,
1498, 1409, 1333, 1271, 1056, 942, 864, 753, 653, 511.
(λ
= 071073
Å) using an
ω–2θ scan technique. The
structures were solved using direct methods and reꢀ
fined by a fullꢀmatrix leastꢀsquares technique. All
nonꢀhydrogen atoms were assigned to anisotropic disꢀ
placement parameters in the refinement. All hydrogen
Synthesis of complex IV. 0.6108 g (0.005 mol) of
,2ꢀaminobenzylamine was added to 30 mL of anhyꢀ
1
drous methanol and (0.5942 g , 0.0025 mol) of NiCl2
⋅
atoms were added at calculated positions and refined
2
6
H O in a dry 100 mL Schlenk flask. The reaction
2
using a riding model. The structures were refined on
F
mixture was refluxed for 72 h. After hot filtration, the
residue was recrystallized with DMF and anhydrous
ethyl ether, and the light blue crystals were obtained.
The yield was 38.6%.
using SHELXTLꢀ97 [12–14]. The crystal used for the
diffraction study showed no decomposition during daꢀ
ta collection. The crystal data and refinement data for
compound I are listed in Table 1. Selected bond
lengths and bond angles are given in the figure
For C H Cl N Ni
2
12
16
4
captions.
anal. calcd., %: C, 41.66;
H, 4.66;
H, 4.52;
N, 16.19.
N, 16.09.
Found, %:
C, 41.46;
Supplementary material has been deposited
with the Cambridge Crystallographic Data Centre
(nos. 818121ꢀ818124); deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk).
1
H NMR (300 MHz; CDCl ; 27
3
°
C; , ppm): 6.93 (t.,
J = 6.5 Hz, 2H), 6.04 (s., 1H),
δ
1
3
3
1
H), 6.11–6.12 (d.,
.82 (s., 4H), 2.11(s., 6H), IR (KBr;
–1
ν
, cm ): 3292,
196, 3164, 3108, 1608, 1572, 1495, 1249, 1219, 1099,
027, 942, 751, 622, 500.
RESULTS AND DISSCUSSION
Synthesis of 2ꢀnitroꢀ1ꢀphenylethanol (V). Catalysts
III, and IV (0.148 mmol), benzaldehyde (0.10 mL, be summarized as follows:
I
,
The synthetic routes of the title four complexes can
II,
THF
+
Ni(OAc)2
⋅
4H O
2
NH2
O
H N
2
O
NH2
Ni
H N
2
O
O
H N
2
NH2
(I)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
No. 8
2012

SYNTHESIS AND CATALYTIC ACTIVITY OF NOVEL Ni–N COMPLEXES
Cl
569
NH2
H N
2
NH2
THF
+
NiCl2
⋅
6H O
2
Ni
Cl
NH2
NH2
H N
2
(II)
2+
H O
2
NH2
NH2
NH2
H N
THF
2
2–
+
Ni(OAc)2
⋅
4H O
2
Ni
(OOCCH3)2 ⋅ 2H O
2
NH2
H N
2
H O
2
(
III
)
2+
NC H O
3
7
NH2
H N
2
NH2
CH OH
3
2Cl–
+
NiCl2
⋅
6H O
2
Ni
NH2
H N
2
NH2
H O
2
(IV)
Table 1. Crystallographic data and refinement details for I–IV
Value
Parameter
I
II
III
IV
Formula weight
Temperature, K
Crystal system
Space group
493.20
291(2)
345.90
291(2)
465.06
293(2)
619.44
293(2)
Monoclinic
Monoclinic
2 /
Triclinic
Monoclinic
P
2 /
1
c
P
c
1
P
1
C2/c
a
, Å
, Å
8.3507(4)
10.9610(6)
13.7503(10)
90.00
11.404(3)
5.9200(14)
12.168(3)
90.00
8.2321(5)
11.2475(6)
13.5369(7)
65.589(4)
74.636(4)
86.903(5)
1098.35(11)
2
39.447(2)
9.8541(4)
18.4277(8)
90.00
b
c
, Å
, deg
, deg
, deg
α
β
106.342(6)
90.00
115.31(3)
90.00
96.583(5)
90.00
γ
Volume, Å3
1207.74(12)
2
742.7(3)
2
7115.9(6)
8
Z
ρ
calcd,
mg/mm3
1.356
1.547
1.406
1.156
F(000)
524
356
488
2672
Crystal size, mm
Range fordata collection, deg
0.34
×
0.31
×
0.30
0.36
×
0.33
×
0.30
0.30
×
0.20
×
0.20
0.40
×
0.40 × 0.30
θ
5.25–62.61
159
4.29–62.68
88
3.72–67.08
264
2.87–26.02
403
Parameter
Goodnessꢀofꢀfit on F2
1.070
1.006
1.092
1.046
Final
R
indexes (
I
> 2σ(I
))
R1 = 0.0334,
wR2 = 0.0946
R1 = 0.0518,
wR2 = 0.1246
R1 = 0.0540,
wR2 = 0.1400
R1 = 0.0581,
wR2 = 0.1533
Final
R
indexes (all data)
R1 = 0.0386,
wR2 = 0.0995
R1 = 0.0611,
wR2 = 0.1291
R1 = 0.0575,
wR2 = 0.1433
R1 = 0.1098,
wR2 = 0.1623
Largest diff. peak/hole,
e
Å–3
0.354/–0.326
0.591/–0.363
0.884/–1.532
0.890/–0.510
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
No. 8
2012

570
MEI et al.
C(25)
C(26)
O(5)
C(18)
O(2)
O(1)
C(27)
C(17)
O(8)
Ni(1)
N(1)
C(9)
N(2)
C(1)
C(2)
C(11)
C(12)
C(10)
O(3)
C(7)
C(6)
C(3)
C(19)
O(4)
C(15)
C(13)
N(4)
C(4)
C(5)
C(14)
C(16)
C(20)
O(6)
C(8)
N(3)
C(22)
C(24)
C(23)
C(21)
O(7)
Fig. 1. The molecular structure of complex
Ni(1)–N(3) 2.116(4), Ni(1)–N(2) 2.129(4), Ni(1)–N(4) 2.140(3), Ni(1)–N(1) 2.148(4), O(3)–C(19) 1.263(5), O(1)–C(17)
.246(5), N(2)–C(9) 1.482(5), N(1)–C(1) 1.464(5) ; O(1)Ni(1)O(3) 87.37(11) , O(1)Ni(1)N(3) 87.71(13) , O(3)Ni(1)N(3)
9.31(12) , O(1)Ni(1)N(2) 89.33(13) , O(3)Ni(1)N(2) 88.60(13) , N(3)Ni(1)N(2) 176.45(14) , O(1)Ni(1)(4) 90.73(14)
O(3)Ni(1)N(4) 178.09(14) N(3)Ni(1)N(4) 90.78(14) N(2)Ni(1)N(4) 91.21(15) O(1)Ni(1)N(1) 175.35(13)
, N(4)Ni(1)N(1) 93.90(15)
I: selected bond lengths and angles, Ni(1)–O(1) 2.105(3), Ni(1)⎯O(3) 2.111(3),
1
8
Å
°
°
°
°
°
°
°,
°
,
°
,
°,
°,
O(3)Ni(1)N(1) 88.00(13)
°
, N(3)Ni(1)N(1) 92.67(15)
°
, N(2)Ni(1)N(1) 90.12(15)
°
°.
Cl(1)
C(3) C(2)
i
N(1)
N(2)
i
C(1)
i
C(6)
C(5)
Ni(1)
i
C(4)
C(4)
C(5)
C(6)
i
i
C(1)
N(2)
i
N(1)
i
C(3)
C(2)
i
Cl(1)
Fig. 2. The molecular structure of complex II
Ni(1)–Cl(1) 2.4551(10), N(1)–C(6) 1.435(5), N(2)–C(1) 1.444(5), N(2)Ni(1)N(1) 81.44(13)
N(1)Ni(1)Cl(1) 89.33(9) , C(6)N(1)Ni(1) 108.4(2) , C(1)N(2)Ni(1) 108.6(2)
:
s
elected bond lengths and angles, Ni(1)–N(2) 2.081(3), Ni(1)–N(1) 2.094(3),
°
, N(2)Ni(1)Cl(1) 87.99(10)
°,
°
°
°.
The synthesis of complex I was carried out in tetꢀ Complex III also contains two molecules of ethanol
rahydrofuran at a ratio of 4 : 1 of the ligand to nickel and two molecules of water with a freed root.
acetate. After refluxing for 24 h, a large amount of blue
solids was obtained. The blue crystals were precipiꢀ
tated after recrystallization from ethanol and hexane.
The synthesis of complex IV was carried out in
anhydrous methanol, using a ratio of 2 : 1 of ligand to
nickel acetate. After refluxing for 72 h, complex IV was
recrystallized with Nꢀdimethylformamide and anhyꢀ
drous ethyl ether (v/v = 1 : 1), and brown crystals were
obtained.
The synthesis of complex II was carried out in tetꢀ
rahydrofuran using a ratio of 2 : 1 of the ligand to
nickel chloride. After refluxing for 72 h, complex II
was recrystallized with Nꢀdimethylformamide, and
The four complexes were all easily dissolved in
dichloromethane, chloroform, ethanol, and methanol
and were difficult to dissolve in hexane, petroleum
ether, and ether. The coordination number was 6 for
the nickel complexes.
brown crystals were obtained at 90°C.
The synthesis of complex III was carried out in tetꢀ
rahydrofuran using a ratio of 2 : 1 of the ligand to
nickel acetate. After refluxing for 72 h, complex III
Complex I contained a Ni(OAc) molecule and two
2
was recrystallized with dichloromethane and
n
ꢀhexꢀ
2+
ane (v/v = 1 : 1), and brown crystals were obtained. 1,3ꢀxylylenediamine molecules. The Ni ion was coꢀ
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
No. 8
2012

SYNTHESIS AND CATALYTIC ACTIVITY OF NOVEL Ni–N COMPLEXES
571
C(4)
C(2)
C(6)
O(1)
i
i
C(1)
C(7)
N(1)
C(5)
i
C(5)
C(6)
C(3)
C(5)
C(7)
i
C(4)
i
N(2)
C(6)
C(4)
C(7)
C(3)
Ni(1)
C(2)
N(2)
C(1)
N(1)
i
i
i
O(1)
C(1)
C(3)
i
N(1)
i
N(2)
C(2)
Cl(1)
C(9)
C(16)'
O(2)
C(15)
N(3) C(8)
Ni(1)
N(4)
C(9)
C(8)
O(2)
O(1)
N(5)' C(15)'
O(3)
C(16)
C(14)
C(13)
C(10)
C(11)
O(4)
Cl(2)
C(17)'
C(17)
C(12)
Fig. 3. The molecular structure of complex III: selected
bond lengths and angles, Ni(1)–O(1) 2.0691(14), Ni(1)–
N(2) 2.1158(17), Ni(1)–N(1) 2.1275(17), N(1) C(1)
.433(3), O(3)–C(8) 1.246(3), O(2)–C(8) 1.245(3),
⎯
1
Fig. 4. The molecular structure of complex IV: selected
bond lengths and angles, Ni(1)–O(1) 2.061(3),
Ni(1) N(1) 2.141(3), Ni(1)–N(2) 2.092(3), Ni(1)–N(4)
2.103(3), Ni(1)–N(3) 2.116(3), Ni(1)–O(2) 2.120(3),
N(2)–C(7) 1.483(5), N(3)–C(8) 1.432(5), N(4)–C(14)
.482(5), N(1)–C(1) 1.445(5), C(15)–N(5) 1.383(4),
N(2)–C(7)
O(1)Ni(1)N(2) 91.33(7)
N(2)Ni(1)N(1) 88.34(7)
C(7)N(2)Ni(1) 115.44(13)
1.478(3),
C(8)–C(9)
O(1)Ni(1)N(1) 85.87(7)
, C(1)N(1)Ni(1) 116.55(12)
1.502(3)
Å
°
°
;
,
,
°
,
⎯
°
°
.
1
C(16)–N(5) 1.384(4)
O(1)Ni(1)N(4) 86.06(14)
O(1)Ni(1)N(3) 173.28(13)
N(4)Ni(1)N(3) 87.86(12)
N(2)Ni(1)O(2) 176.17(12)
N(3)Ni(1)O(2) 91.92(12)
N(2)Ni(1)N(1) 89.62(12)
N(3)Ni(1)N(1) 94.46(12)
C(7)N(2)Ni(1) 115.6(2)
C(8)N(3)Ni(1) 114.9(2)
Å
°
;
O(1)Ni(1)N(2) 86.91(13)
, N(2)Ni(1)N(4) 93.38(12)
, N(2)Ni(1)N(3) 90.59(12)
, O(1)Ni(1)O(2) 90.90(12)
, N(4)Ni(1)O(2) 89.60(12)
, O(1)Ni(1)N(1) 91.76(13)
, N(4)Ni(1)N(1) 176.19(13)
°
°
°
°
°
°
°
°
°
°
,
,
,
,
,
,
,
,
,
,
ordinated with two oxygen atoms, O(1) and O(3), and
with nitrogen atoms N(1), N(2), N(3), and N(4) from
two 1,2ꢀaminobenzylamine molecules (Fig. 1).
Thus, the complex was sixꢀcoordinate, and three
molecules of ethanol and one molecule of methanol
were rooted out.
°
°
°
°
°
°
,
, O(2)Ni(1)N(1) 87.31(12)
C(15)O(1)Ni(1) 139.2(4)
, C(14)N(4)Ni(1) 118.6(2)
°
°
Complex II also consisted of one NiCl molecule
C(1)N(1)Ni(1) 115.4(2)°.
2
and two 1,2ꢀaminobenzylamine molecules. The Ni2
ion was coordinated with two atoms Сl(1) and Cl(2)i
and with two 1,2ꢀaminobenzylamine nitrogen atoms
+
O
i
i
N(1), N(2), N(1) , and N(2) (Fig. 2). Thus, the comꢀ
plex was sixꢀcoordinate.
H
+
CH OH
3
Similarly complex III was a Ni–N complex that
1
5 mol % complexes
CH OH
consisted of a Ni(OAc) molecule and two 1,2ꢀamiꢀ
nobenzylamine molecules. A Ni ion was complexed
OH
H
2
NO2
3
2+
NO2
–H O
2
i
with two oxygen atoms, O(1) and O(1) of two water
molecules, and with nitrogen atoms N(1), N(2),
H
i
i
(V
)
(VI)
N(1) , and N(2) from two 1,2ꢀaminobenzylamine
molecules (Fig. 3). Thus, the complex was sixꢀcoordiꢀ
nate.
Based on Table 2, the conversion effciency for each
of these complexes was high than 80%; thus, they are
all good catalysts for the Henry reaction. In this reacꢀ
tion, the overall conversion rate was high, but
Complex IV consisted of a NiCl molecule and two
2
2+
1,2ꢀdiaminobenzene molecules. The Ni ion was
coordinated with one molecule of DMF solvent, one
water molecule, and the nitrogen atoms N(1), N(2), Table 2. Catalytic activity of complexes
N(3), and N(4) of two 1,2ꢀdiaminobenzene (Fig. 4), reaction
forming a sixꢀcoordinate complex with two chloride
I
–
IV for the Henry
Complex
Conversion, % (
V)
Yield, % (VI
)
ions rooted out.
I
>99
82
32
24
20
64
Catalysis of the Henry reaction was achieved using
5 mol % of the four complexes without any additives.
The catalytic activity of the four novel complexes in
the Henry reaction is shown in Table 2.
II
1
III
IV
>99
86.4
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
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2012

5
72
MEI et al.
2. Groux, L.F. and Zargarian, D., Organometallics, 2003,
compound
Products
The configuration of V was identified as the Eꢀconfigꢀ
V
was prone to dehydration to form VI
.
1
vol. 22 , p. 3124.
. Fujiwara, E., Kobayashi, A., Fujiwara, H., and Kobaꢀ
yashi, H., Inorg. Chem., 2004, vol. 43, p. 1122.
. Byun, J.C. and Kim, K.J., Inorg. Chem. Commun.,
V
and VI were characterized using H NMR.
3
4
5
6
7
8
9
1
uration by H NMR experiments.
Among the four complexes, complex I showed the
2007, vol. 10, p. 502.
best catalytic activity. The following mechanism can
be proposed: the complexes activate the C=O bond,
and then there is a nucleophilic addition reaction of
−
. Manca, G., Cano, J., and Ruiz, E., Inorg. Chem., 2009,
vol. 48, p. 3139.
. Li, Y.F. and Wang, L., Appl. Organometal. Chem., 2006,
vol. 20, p. 436.
. Soloshonok, V.A., Cai C.Z., and Hruby, V.J., Tetraheꢀ
dron: Asymmetry, 1999, vol. 10, p. 4265.
. Koehn, U., Schulz, M., Goerls, H., and Anders, E.,
CH NO2 to the carbonyl group.
2
In conclusion, four complexes were first syntheꢀ
sized with a simple oneꢀpot method, and their crystal
structures were determined. The four complexes were
first applied in the Henry reaction and achieved good
effects. Additional research on the use of these comꢀ
plexes in other organic reactions, such as the Baylis–
Hillman reaction and allylation, is ongoing.
Tetrahedron: Asymmetry, 2005, vol. 16, p. 2125.
. Gonzal, B., Estela, C., Isabel, F., et al., Tetrahedron:
Asymmetry, 2007, vol. 18, p. 1603.
0. Marianne, S. and Carsten, B., J. Org. Chem., 2010,
vol. 75, p. 3301.
1. Luo, M. and Yan, B., Tetrahedron Lett., 2010, vol. 51,
p. 5577.
1
1
1
ACKNOWLEDGMENTS
2. Sheldrick, G.M., SHELXSꢀ97
Crystal Structure Solution, G ttingen (Germany): Univ.
of G ttingen, 1997.
3. Sheldrick, G.M., SHELXLꢀ97
Crystal Structure, G ttingen (Germany): Univ. of G
tingen, 1997.
4. Stout, G.H. and Jensen, L.H., XꢀRay Structure Deterꢀ
mination a Practical Guide, New York: MacMillan,
1968.
, Program for XꢀRay
ö
This work was supported by the Hefei University of
Technology.
ö
1
1
,
Program for Xꢀray
tꢀ
ö
ö
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No. 8
2012