"click" tetradentate ligands

Article abstract of DOI:10.1039/b922043g

A series of triazole-based N4 tetradenate ligands 1a-d are efficiently synthesized using Cu^I-catalyzed azide-alkyne "click" strategy and are readily coordinated to many metal ions (e.g. Mn^II, Ni^II, Zn^II and Fe^II). The X-ray structures of the resultant metal-complexes (4a-d, 5a, 6a and 7a) reveal an octahedral mononuclear structure with two co-ligands bonded in cis sites and the two triazoles as nitrogen donors to the metal center. The Mn^II-complexes (4a-d) show efficient catalytic activities in the epoxidation of various aliphatic terminal olefins with peracetic acid, and feature with low catalyst loading, fast conversion and high yields. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/b922043g

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PAPER
www.rsc.org/dalton | Dalton Transactions
“
Click” tetradentate ligands†
Erhong Hao,* Zhaoyun Wang, Lijuan Jiao and Shaowu Wang*
Received 21st October 2009, Accepted 17th December 2009
First published as an Advance Article on the web 22nd January 2010
DOI: 10.1039/b922043g
I
A series of triazole-based N4 tetradenate ligands 1a–d are efficiently synthesized using Cu -catalyzed
II
II
II
azide-alkyne “click” strategy and are readily coordinated to many metal ions (e.g. Mn , Ni , Zn and
II
Fe ). The X-ray structures of the resultant metal-complexes (4a–d, 5a, 6a and 7a) reveal an octahedral
mononuclear structure with two co-ligands bonded in cis sites and the two triazoles as nitrogen donors
II
to the metal center. The Mn -complexes (4a–d) show efficient catalytic activities in the epoxidation of
various aliphatic terminal olefins with peracetic acid, and feature with low catalyst loading, fast
conversion and high yields.
Introduction
reaction has been widely used in organic synthesis and features
with high yields, high efficiency, mild reaction conditions, and
Tetradentate ligands have been widely used in coordination,
biological, synthetic, and supramolecular chemistry, as well as
in the development of sensors and molecular switches. Among
10
simple work-up procedures. The resulting 1,2,3-triazole itself has
11,12
attracted growing interest
type ligands.
in the design of tridentate pincer-
1
11b-c,12a
Clearly, the “click” strategy could be an ideal
those, N4 tetradentate ligands have been extensively used for
the construction of various metal-coordination complexes used
as bioinspired non-heme catalysts for many important and chal-
method for achieving non-pyridyl-based N4 tetradentate ligands,
since its application to various commercially or readily available
azides and alkynes will result in a wide variety of tetradentate
ligands.
Herein, we report the “click” syntheses of triazole-based N4
tetradentate ligands 1a–d, and the X-ray structures of their metal
complexes 4a–d, 5a, 6a and 7a. To demonstrate the application
2,3
lenging catalytic processes. The key features of these catalysts,
including activity, selectivity, and stability are dictated by the
steric and electronic properties of these ligands coordinated to the
4
metal. Consequently, ligand variation becomes the most powerful
tool in the optimization of these catalysts, and most efforts in the
area of catalysis have been put into the design of novel suitable
ligands. Still, there is limited access to N4 tetradentate ligands,
of our non-pyridyl-based ligands in catalysis, their manganese
II
(
Mn ) complexes 4a–d have been used in the epoxidation of
various terminal aliphatic olefins with peracetic acid, in which
these complexes show good catalytic activities, and feature with
low catalyst loading, fast conversion and high yields.
5
and most of them are based on a pyridyl-framework, such as
6
7
3b,8
tpa, mep and pbp as shown in Fig. 1. The limited modification
methods for the pyridyl-framework result in the limited synthetic
variations of these N4 tetradentate ligands. Thus it is necessary to
develop a novel non-pyridyl-based N4 tetradentate ligand system
and an efficient construction method for such a system.
Results and discussion
Ligands 1a–d were synthesized in 57–71% overall yield by treating
acetylene 2 with aromatic azides 3a–d in a one-pot two-step
procedure as shown in Scheme 1. The syntheses of these ligands
are readily scaled up to the multigram scale without column chro-
matography using readily available aromatic azides 3 as starting
13
materials. The triazole unit of these ligands offers an alternative
framework to that pyridyl-based traditional framework, and can
easily be used for further functionalization.
Fig. 1 Examples of N4 tetradentate ligands.
I
We were attracted to the Cu -catalyzed cycloaddition of azides
and terminal alkynes known as “click chemistry” by Sharpless
9
et al., and the 1,2,3-triazoles from this “click” reaction. “Click”
Laboratory of Functional Molecular Solids, Ministry of Education, and
Anhui Laboratory of Molecule-Based Materials, School of Chemistry and
Material Science, Anhui Normal University, Wuhu, Anhui, China 241000.
E-mail:
haoehong@mail.ahnu.edu.cn,
swwang@mail.ahnu.edu.cn;
Fax: +86-553-388-3517
†
7
CCDC reference numbers 734010–734012, 736726, 736933, 736996 and
36997. For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b922043g
Scheme 1 Synthesis of ligands 1a–d.
2
660 | Dalton Trans., 2010, 39, 2660–2666
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To demonstrate the good coordination properties of nitrogen in
Ligands 1b–d exhibit similar coordination properties to these
metal ions and smoothly generated complexes 4b–d in 60–87%
yields. Complexes 4b–d were characterized by MS, elemental and
these ligands, ligand 1a was initially studied. It readily coordinated
II
II
II
II
to Mn , Ni , Zn and Fe metal ions as shown in Scheme 2, and
generated the corresponding metal complexes 4a–7a in 77, 42, 53
and 82% yields respectively. Complexes 4a–7a were characterized
14
X-ray analyses. The X-ray structures of complexes 4a–d, shown
in Fig. 2 and Fig. 3, are similar to the pyridyl-based complex
14
II
4b
by MS, elemental and X-ray structure analyses. Their X-ray
structures reveal an octahedral mononuclear structure with the
[Mn (R,R-mcp)(CF
3
SO
3
)
2
]
in which the average bond length
II
˚
of the pyridyl-nitrogen to Mn is 2.25 A. Complex 4d exhibits
a relatively shorter average bond length (2.22 A) between Mn
II
˚
two triazoles as nitrogen donors to the metal center and two co-
-
˚
and the triazole-N nitrogen compared to those of 4a (2.29 A),
ligands (CF
3
SO
3
for 4a, H
2
O for 5a–6a and MeCN for 7a) bonded
3
˚
˚
in cis sites as shown in Fig. 2. The bond lengths of the triazole-
4b (2.29 A) and 4c (2.30 A). This difference may be due to the
II
II
II
II
N
3
nitrogen’s to Mn , Ni , Zn and Fe are 2.29, 2.09, 2.12 and
electron-donating effect from methoxy-substituents in complex
˚
2
.15 A respectively, similar to those in the pyridyl-based metal-
4d.
15
complexes.
Scheme 2 Synthesis of metal complexes 4a–7a.
Fig.
3
X-Ray structures of catalysts 4b, 4c and 4d. (A):
II
II
[
[
Mn (CF
Mn (CF
3
SO
SO
3
)
)
2
(1b)] (4b); (B): [Mn (CF
(1d)] (4d). Hydrogen atoms and non-coordinating solvent
3
SO
3
)
2
(1c)] (4c) and (C):
II
3
3
2
molecules have been omitted for clarity. Average Mn–N (triazole) lengths
A˚ ]: for 4b, 2.29; for 4c, 2.30 and for 4d, 2.22. C gray, Mn dark-green, N
[
blue, O red, S yellow and F bright-green.
The facile access to these triazole-based N4 tetradentate ligands
opens a way to the rapid and convenient construction of a
variety of metal complexes and the screening of their catalytic
properties. We are attracted to the catalytic epoxidation of terminal
olefins, because the resulting 1,2-epoxides are extremely versatile
starting materials for the syntheses of more complicated molecules
while the reaction itself remains challenging due to the relatively
16
electron-deficient nature of these olefins. Recently, Stack, Costas
4b,5b,17
and Que have disclosed several efficient catalysts
based on
the pyridyl-fragment for the epoxidation of terminal olefins. With
metal complexes of ligands 1a–d in hand, and to exemplify the
advantages of these resultant ligands, we investigated the catalytic
II
activities of their Mn -complexes 4a–d in the epoxidation of
terminal olefins.
The initial screening of the catalytic activities of these complexes
in the epoxidization of terminal olefins was performed on 1-
tetradecene with peracetic acid as the oxidant. Typically, two
equivalents of peracetic acid (8–10%) is slowly added into the
system containing the catalyst, and the results are summarized in
Table 1. Complexes 4a–d are powerful catalysts in the epoxidiza-
tion of 1-tetradecene. With 2 mol% catalyst loading, complexes
4a–4d were able to generate the desired 1,2-epoxytetradecane
in 79%–89% conversion respectively within 3 min (entries 1–4
II
Fig. 2 X-Ray structures of catalysts 4a–6a. (A): [Mn (CF
3
SO
3
)
2
(1a)]
(6a)
II
II
(
4a); (B): [Ni (H
2
O)
2
(1a)](ClO
4
)
2
(5a); (C): [Zn (H
2
O)
2
4 2
(1a)](ClO )
II
and (D): [Fe (MeCN)
2
(1a)] (7a). Hydrogen atoms and non-coordinating
solvent molecules have been omitted for clarity. Average M–N (triazole)
lengths [ A˚ ]: for 4a, 2.29; for 5a, 2.09; for 6a, 2.12 and for 7a, 2.15 A˚ . C
grey, N blue, O red, S yellow, F bright-green, M dark green, Ni light
II
II
II
II
blue, Zn light green and Fe green.
This journal is © The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 2660–2666 | 2661

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a
a
Table 1 Epoxidation reactivity of catalysts 4a–d
Table 2 Epoxidation reactivity of catalyst 4d for various terminal olefins
Entries
Catalyst
Catalyst loading (%)
Conversion (%)
Entries
R
n
Isolated yield (%)
b
b
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4d
4d
4d
4d
4d
4d
4d
2
2
2
2
81
1
2
3
4
5
6
7
Me
Me
Me
Me
Me
MeOC(O)
EtOC(O)
7
9
11
13
15
8
93
b
82
94
89
b
71
b
c
89c
83
c
2
98
79
89
c
b
0.5
0.1
0.1
0.5
0.5
0.5
81c
b
67
75
87
90
8
91
c,d
c,e
a
-2
Performed with olefins (5.0 mmol) and catalyst 4d (2.5 ¥ 10 mmol) in
c,f
1
1
0
1
9 mL CH
2
Cl
2
–CH
3
CN (v/v = 1/1); CH
3
CO
3
H (7.65 g, 10%, 10.0 mmol)
c,d
◦
98
was added over 30 min; reaction time: 3 min; reaction temperature: 0 C
unless noted otherwise. Results are the average of at least three runs.
MeCN (9 mL) was used as solvent. Reaction was performed at room
a
b
c
Performed with 1-tetradecene (5.0 mmol), catalyst (2.5 mmol% for 0.5%
H, 10.0 mmol); reaction
temperature 0 C, reaction time: 3 min. Results are the average of at least
catalyst loading), CH
3
CO
3
H (7.65 g, 10% CH
3
CO
3
temperature.
◦
b
c
three runs. Addition of CH
over 30 min. CH
CH
3
CO
2
3
H over 10 min. Addition of CH
3
CO
3
H
d
e
3
CN–CH
2
Cl
= 1/1 (v/v) was used as solvent. CH
3
CN–
great opportunities for the efficient screening of a broad range of
organometallic catalysts. These advantages are exemplified here
by applying their Mn complexes 4a–d for the efficient catalytic
f
2
Cl
2
= 10/1 (v/v) was used as solvent. CH
3
CN–CH
2
Cl
2
= 5/1 (v/v)
was used as solvent.
II
epoxidation of various aliphatic terminal olefins. Extending this
synthetic strategy to the synthesis of various nitrogen donor
ligands, including chiral N4 tetradentate ligands and their metal
complexes for further applications in the selective or asymmetrical
oxidation of aliphatic C–H bonds are currently under way.
in Table 1). Catalyst 4d based on ligand 1d with more
electron-rich triazole rings, shows the highest catalytic activity
(
entry 4 in Table 1), giving comparable catalytic performance to
II
4b
that of [Mn (mep)(CF
3
SO ) ]. Although 1-tetradecene is rapidly
3
2
expoxidized with 0.1 mol% catalyst loading of 4d (entry 8 in
Table 1), it generally requires 0.5 mol% catalyst loading with
the slight modification of the reaction conditions to achieve the
complete conversion of 1-tetradecene (entry 11 in Table 1).
To test the versatility of catalyst 4d in the epoxidation of
olefins, the optimized reaction conditions were further applied to
other aliphatic terminal olefins and the results are summarized in
Table 2. The epoxidations are generally accomplished at 0.5 mol%
catalyst loading of 4d. Catalyst 4d showed good catalytic activity
Experimental
General
Reagents were purchased as reagent-grade and used without
further purification unless otherwise stated. Solvents were used
as received from commercial suppliers unless noted otherwise.
Acetonitrile was distilled over CaH . THF was freshly distilled
2
◦
towards various terminal olefins studied. At either 0 C or room
from sodium benzophenone ketyl. All olefin substrates used were
purchased from a commercial source. Peracetic acid (8–10%)
temperature within 3 min, the desired epoxidation products were
generated in high isolated yields (79–94%). There are few reports
about the epoxidation of these long-chain aliphatic terminal
olefins, such as 1-tetradecene, 1-hexadecene and 1-octadecene
18
was prepared according to the literature. All reactions were
performed in oven-dried or flame-dried glassware unless otherwise
stated, and were monitored by TLC using 0.25 mm silica gel plates
(
entries 3–5 in Table 2) associated with their low solubility in
with UV indicator (60F-254) or I
2
vapor. Reactions involving light-
MeCN. The usage of the mixture solvent (MeCN–CH Cl ) in our
2
2
sensitive compounds such as CuI were carried out wrapped in foil.
1
13
system is able to improve the solubility of these long chain olefins
and leads to good epoxidation yields. Catalyst 4d also shows well
catalytic performance in the epoxidation of internal olefin, for
example cyclooctene (92% isolated yield) as shown in Scheme 3.
H- and C-NMR are obtained on an AV-300 Bruker spectrometer
at 298 K; chemical shifts (d) are reported in d [ppm] relative to
1
13
CDCl
3
(7.26 ppm, H; 77.3 ppm, C) or DMSO-d (2.50 ppm,
6
1
13
H; 40.5 ppm, C); coupling constants J are given in [Hz] and the
multiplicities are expressed as follows: s = singlet, d = doublet, t =
triplet, m = multiplet. ESI-MS spectra were obtained on Agilent-
6
220. Elemental analysis was obtained on VarioEL III.
Syntheses
Scheme 3 Catalytic epoxidation of cyclooctene.
N,N-dimethyl-N,N-di(prop-2-ynyl)ethane-1,2-diamine 2. To
N,N-dimethylethanamine (370 mg, 4.2 mmol) in dry DMF (5 mL)
◦
at 10 C was added anhydrous potassium carbonate (1.73 g,
1
Conclusions
2.5 mmol) in one portion, and propargyl bromide (1.01 g,
In summary, we have developed a conceptually new approach
for the synthesis of a series of triazole-based N4 tetradentate
ligands using the “click-chemistry” method. These ligands have
good coordination properties to many metal ions, and provide
8.5 mmol) in DMF (5 mL) dropwise over 1 h. After stirring at
10 C for 8 h, the reaction mixture was filtered off, and the solid
was washed with DMF (2 ¥ 3 mL). Organic layers were combined,
poured into water (100 mL), extracted with DCM (3 ¥ 30 mL),
◦
2
662 | Dalton Trans., 2010, 39, 2660–2666
This journal is © The Royal Society of Chemistry 2010

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washed with water (3 ¥ 100 mL), and dried over anhydrous MgSO
Solvent was removed under reduced pressure, and the pure 2 was
4
.
4a in 77% yield (584 mg). X-Ray quality crystals were obtained
by slow diffusion of Et
HRMS: calcd. for C22
Anal. calcd. for C24
found: C, 38.03; H, 3.51; N, 14.63.
2
O into its concentrated MeCN solution.
Mn m/z 228.5830, found 228.5857.
MnN : C, 38.15; H, 3.47; N, 14.83.
obtained as a yellow oil in 92% yield (634 mg) from column
H
F
26
N
8
1
chromatography (silica gel, EtOAc/petroleum ether = 1/2). H
H
26
6
8
O
6
S
2
NMR (300 MHz, CDCl ): d 3.32 (s, 4H), 2.47 (s, 4H), 2.24 (s, 6H),
3
1
3
2
.16 (s, 2H). C NMR (75 MHz, CDCl
3
): d 78.1, 73.3, 52.5, 45.3,
Complex 4b. Following the procedure for 4a but replacing 1a
with 1b (458 mg, 1.0 mmol) (64% yield). X-Ray quality crystals
41.6.
One-pot syntheses of ligands 1. To N,N-dimethylethanamine
502 mg, 5.7 mmol) in THF (5 mL) at 10 C was added anhydrous
were obtained by slow diffusion of Et O into its concentrated
2
◦
(
MeCN solution. HRMS: calcd. for C H MnN m/z 256.7793,
2
6
34
8
potassium carbonate (2.35 g, 17.0 mmol) in one portion, and
propargyl bromide (1.35 g, 11.4 mmol) in THF (5 mL) dropwise
over 1 h. After stirring at 10 C for 8 h, the reaction mixture was
found 256.7771. Anal. calcd. for C H F MnN O S : C, 41.43; H,
4.22; N, 13.81. found: C, 41.77; H, 4.31; N, 14.20.
2
8
34
6
8
6
2
◦
Complex 4c. Following the procedure for 4a but replacing 1a
with 1c (493 mg, 1.0 mmol) (60% yield). X-Ray quality crystals
filtered off and washed with THF (2 ¥ 2.5 mL). Organic layers
were combined and poured into aromatic azides 3a–d (17 mmol,
were obtained by slow diffusion of Et
MeCN solution. HRMS: calcd. for C22
found 273.6793. Anal. calcd. for C24
H, 2.86; N, 16.56; found: C, 34.31; H, 3.11; N, 16.70.
2
O into its concentrated
m/z 273.6812,
: C, 34.09;
13
generated according to the literature ) in THF (15 mL). To
the reaction mixture was added CuI (1.10 g, 5.7 mmol) and
triethylamine (2 mL), and was stirred at room temperature in
the dark for 24 h according to TLC. The reaction mixture was
H
24MnN10
F
O
4
H
24
6
MnN10
O
10
S
2
diluted with aqueous NH
DCM (3 ¥ 50 mL), dried over anhydrous MgSO
3
·H
2
O (100 mL, 5%), extracted with
, and concentrated
Complex 4d. Following the procedure for 4a but replacing 1a
with 1d (463 mg, 1.0 mmol) (87% yield). X-Ray quality crystals
4
in vacuum to obtain a crude oil residue. It was washed with
petroleum ether (3 ¥ 30 mL) to give the desired analytical pure
products 1a–d as light brown powers.
were obtained by slow diffusion of Et O into its concentrated
2
MeCN solution. HRMS: calcd. for C H MnN O m/z 258.5936,
2
4
30
8
2
found 258.5901. Anal. calcd. for C H F MnN O S : C, 38.29; H,
2
6
30
6
8
8
2
Ligand 1a. As described in the general procedure (66% yield).
3.71; N, 13.74; found: C, 38.57; H, 3.98; N, 13.88.
1
H NMR (300 MHz, CDCl
3
): d 8.00 (s, 2H), 7.62 (d, J = 9 Hz, 4H),
Complex 5a. To 1a (403 mg, 1.0 mmol) in MeCN (6 mL) was
7
2
1
[
6
.36–7.31 (m, 4H), 7.27–7.25 (m, 2H), 3.68 (s, 4H), 2.53 (s, 4H),
II
added Ni (ClO
solution was obtained. After vigorous stirring for 24 h, the reaction
mixture was concentrated in vacuo, MeOH was added, Et O was
carefully layered on the solution, crystals were obtained over 12 h
and washed with cold Et O to yield complex 5a in 40% yield
276 mg). X-Ray quality crystals were obtained by slow diffusion
4
)
2
·H
2
O (366 mg, 1.0 mmol), and a homogeneous
1
3
.18 (s, 6H). C NMR (75 MHz, CDCl ): d 144.7, 136.8, 129.6,
3
28.5, 121.3, 120.2, 54.0, 52.1, 42.2. HRMS: calcd. for C22
H
N : C,
8
27
N
8
+
2
M + H] 403.2358, found 403.2361. Anal. calcd. for C22
H
26
5.65; H, 6.51; N, 27.84. found: C, 65.38; H, 6.48; N, 27.79.
Ligand 1b. As described in the general procedure (58% yield).
2
(
1
H NMR (300 MHz, CDCl
3
): d 7.69 (s, 2H), 7.32 (t, J = 7.5 Hz,
.8 Hz, 2H), 7.16 (d, J = 7.5 Hz, 4H), 3.92 (s, 4H), 2.75 (s, 4H),
.36 (s, 6H), 1.97 (s, 12H). C NMR (75 MHz, CDCl ): d 143.4,
35.9, 135.3, 130.0, 128.7, 125.1, 53.6, 52.4, 42.0, 16.8. HRMS:
of Et O into its concentrated MeCN solution. HRMS: calcd.
2
7
2
1
for C22
H
26
N
8
Ni m/z 230.0817, found 230.0819. Anal. calcd. for
NiO10: C, 37.96; H, 4.34; N, 16.10; found: C, 37.78;
1
3
3
C
22
H
30Cl
2
N
8
H, 4.29; N, 15.93.
+
calcd. for C26
calcd. for C26
H, 7.18; N, 24.71.
H
35
N
8
[M + H] 459.2985, found 459.3029. Anal.
: C, 68.09; H, 7.47; N, 24.43. found: C, 67.92;
H
34
N
8
Complex 6a. To 1a (403 mg, 1.0 mmol) in MeCN (6 mL) was
II
added Zn (ClO
4
)
2
·H
2
O(372 mg, 1.0 mmol), and a homogeneous
O was
carefully layered on the solution. Crystals were obtained over 12 h
and washed with cold Et O to yield a light colour crystal 6a in
53% (373 mg) yield. X-Ray quality crystals were obtained by slow
Ligand 1c. As described in the general procedure (71% yield).
solution was obtained. After vigorous stirring for 24 h, Et
2
1
H NMR (300 MHz, CDCl
s, 2H), 8.02 (d, J = 8.6 Hz, 4H), 3.84 (s, 4H), 2.68 (s, 4H), 2.34
s, 6H). C NMR (75 MHz, CDCl ): d 147.1, 146.1, 141.1, 125.5,
3
): d 8.40 (d, J = 7.8 Hz, 4H), 8.26
(
(
1
2
1
3
3
+
1
21.2, 120.3, 54.2, 52.3, 42.5. HRMS: calcd. for C22
H
24
N
10
O
4
[M]
diffusion of Et
(300 MHz, DMSO-d
7.65 (m, 6H), 4.11–3.94 (m, 4H), 2.73 (s, 4H), 2.51 (s, 6H).
NMR (75 MHz, DMSO-d ): d 144.0, 136.6, 130.6, 130.4, 123.3,
121.1, 52.3, 42.9, 39.1. HRMS: calcd. for C22
465.1494, found 465.1578; calcd. for C22
found 233.0810. Anal. calcd. for C22
2
O into its concentrated MeCN solution. H NMR
4
92.1982, found 492.1962. Anal. calcd. for C22
H
24
N
10
O
4
: C, 53.65;
6
): d 9.08 (s, 2H), 8.01–7.98 (m, 4H), 7.71–
1
3
H, 4.91; N, 28.44. found: C, 53.37; H, 4.76; N, 28.69.
Ligand 1d. As described in the general procedure (57% yield).
C
6
1
+
H NMR (300 MHz, CDCl
H), 7.00 (d, J = 8.3 Hz, 4H), 3.85 (s, 6H), 3.82 (s, 4H), 2.67
t, 4H), 2.34 (s, 6H). C NMR (75 MHz, CDCl ): 159.6, 145.1,
30.5, 121.9, 121.0, 114.7, 55.5, 54.3, 52.5, 42.5. HRMS: calcd.
3
): 7.93 (s, 2H), 7.63 (d, J = 8.6 Hz,
H
25
N
8
Zn [M - H]
Zn m/z 233.0786,
ZnO10: C, 37.60; H,
4
(
1
H
25
N
8
1
3
H
30Cl
2
N
8
3
4.30; N, 15.94; found: C, 37.24; H, 4.41; N, 15.72.
+
for C24
H
30
N
8
O
2
[M] 492.2492, found 492.2497. Anal. calcd. for
Complex 7a. Using a one-pot two-step procedure (82% overall
C
24
H
30
N
8
O
2
: C, 62.32; H, 6.54; N, 24.23. found: C, 62.08; H, 6.25;
yield), to ligand 1a (500 mg, 1.2 mmol) in CH
3
CN (7 mL) was
N, 24.47.
II
added Fe Cl
under argon. With the addition of Fe Cl
precipitate instantly formed. After continuous stirring for 24 h,
Et O was added until no more precipitate formed. After removing
2
·4H
2
O (247 mg, 1.2 mmol) at room temperature
II
Complex 4a. To ligand 1a (403 mg, 1.0 mmol) in MeCN (6 mL)
2
·4H
2
O, a bright orange
II
19,20
was added Mn (CF
homogeneous solution was vigorous stirred for 24 h, and Et
carefully layered on the top of the solution. Crystals were obtained
over 12 h and washed with cold Et O to yield a light colour crystal
3
SO
3
)
2
(353 mg, 1.0 mmol).
The resulting
2
O was
2
solvent, the precipitate was washed thoroughly with ether (5 ¥
3 mL), and dried under argon over night to yield the complex
2
This journal is © The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 2660–2666 | 2663

View Article Online
Table 3 Details of structure determination, refinement, and experimental parameters for complexes 4a–7a
5a 6a
4
a
7a
Formula
C
755.59
Monoclinic
C2/c
0.30 ¥ 0.20 ¥ 0.20
19.148(7)
8.570(3)
20.170(7)
90.00
106.082(4)
90.00
3180.3(19)
4
24
H
26
F
6
MnN
8
O
6
S
2
C
752.21
Monoclinic
C2/c
0.40 ¥ 0.20 ¥ 0.20
7.899(5)
18.312(5)
22.243(5)
90.00
92.183(5)
90.00
3215(2)
4
22
H
38Cl
2
N
8
NiO13
C
22
H
30Cl
2
N
8
O
10Zn
26 32 2
C H F12FeN10Sb
1011.97
Orthorhombic
Pcca
0.45 ¥ 0.25 ¥ 0.20
30.139(5)
11.190(5)
22.140(5)
90.000(5)
90.000(5)
90.000(5)
7467(4)
Formula wt
Crystal system
Space group
Crystal size/mm
a/A˚
b/A˚
c/A˚
702.81
Monoclinic
P2 /c
0.50 ¥ 0.30 ¥ 0.20
16.1160(12)
11.5326(8)
18.0774(13)
90.00
113.0980(10)
90.00
3090.5(4)
4
1.510
1.031
1448
1.37–25.00
21 604
1
◦
a/
◦
b/
◦
g /
V/A˚
3
Z
8
-
3
D
c
/mg m
1.578
0.634
1540
2.10–25.00
10 989
1.554
0.844
1568
1.83–25.00
11 242
1.800
1.914
3952
1.82–25.00
33 857
-1
m/mm
F(000)
q range/
◦
Reflns. collected
Reflns. unique
2802
2837
5453
6584
Parameters
Goodness-of-fit on F
243
1.017
0.0308, 0.0825
0.0400, 0.0891
0.329, -0.269
211
1.146
0.1030, 0.2926
0.1643, 0.3436
1.215, -0.616
400
1.087
0.0442, 0.1330
0.0545, 0.1426
1.303, -0.459
467
1.232
0.0840, 0.2089
0.1685, 0.2509
1.300, -1.595
2
R
R
1
, wR
, wR
2
[I > 2s(I)]
1
2
[all data]
Max, min Dr/e A˚
-3
1
a·FeCl
2
in 82% yield (538 mg) (HRMS: calcd. for C22
H
26
N
8
FeCl
Fourier syntheses. The final refinement was performed by full-
matrix least-squares methods with anisotropic thermal parameters
for non-hydrogen atoms on F . The hydrogen atoms were added
+
[M - Cl] 493.1318, found 493.1332.) which was directly used
2
to react with AgSbF
in dark under argon to generate complex 7a. After stirring for
4 h, the reaction mixture was filtered through Celite three times.
6
(703 mg, 2.1 mmol) in CH
3
CN (14 mL)
theoretically and riding on the concerned atoms.
2
Organic layers were combined, filtered through filter paper and
Catalytic properties
concentrated to give complex 7a (645 mg) as a light colour solid.
◦
General procedure for epoxidation reactions. At 0 C, to the
HRMS: calcd. for C22
Anal. calcd. for C26
3.60. found: C, 30.21; H, 3.42; N, 13.71.
H
26
N
8
Fe m/z 229.0815, found 229.0821.
olefin (5.0 mmol) in MeCN (5 mL) was added catalyst 4a–d (0.5-
CO H (7.65 g, 10%,
0.0 mmol) over 5 or 30 min. The reaction mixture was stirred at
H
32
F
12FeN10Sb
2
·H O: C, 30.32; H, 3.33; N,
2
1
1
0
0 mmol%) in MeCN in one portion, and CH
3
3
1
◦
C for 3 min, quenched with Et
3
N, diluted with H O (50 mL),
2
and extracted with pentane (2 ¥ 40 mL) or petroleum ether (boiling
point: 30–40 C) (2 ¥ 40 mL) depending on the volatility of the
products. Organic layers were combined, washed sequentially with
X-Ray crystallography
◦
Crystallographic data for complexes 4–7a are shown in Table 3,
and those for 4b–d are shown in Table 4. X-Ray quality crystals
were obtained by slow diffusion of Et
H O (2 ¥ 50 mL) and saturated NaHCO (1 ¥ 40 mL), dried over
2
3
2
O into concentrated MeCN
anhydrous K CO , filtered, and carefully concentrated in vacuum
2
3
solution of the corresponding complexes. The vial containing this
solution was placed, loosely capped, to promote the crystallization
upon ether diffusion.
A suitable crystal was chosen and mounted on a glass fiber
using grease. Data were collected using a Bruker SMART APEX-
in an ice bath.
2
1
1,2-Epoxydecane . 1-Decene (745 mg, 94% pure, 5.0 mmol)
-
2
in 5 mL CH CN; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in 4 mL
3
CH
3
CN; CH
3
CO
3
H (7.65 g, 10%, 10.0 mmol) was added over
◦
3
0 min; reaction time: 3 min; reaction temperature: 0 C; workup
2
diffractometer equipped with a graphite crystal monochroma-
using pentane (2 ¥ 50 mL). Three trials provided the product in
tor situated in the incident beam for data collection at room
1
9
1
1
3% isolated average yield. H NMR (300 MHz, CDCl
3
) d 2.88 (m,
21
temperature. Cell parameters were retrieved using SMART
H), 2.74 (t, J = 5.0 Hz, 1H), 2.46 (dd, J = 3.0 and 5.5 Hz, 1H),
software and refined using SAINT on all observed reflections. The
determination of unit cell parameters and data collections were
1
3
.55–1.27 (m, 14H), 0.87 (t, J = 7.0 Hz, 3H). C NMR (75 MHz,
CDCl
3
) d 52.6, 47.4, 32.7, 32.1, 29.74, 29.67, 29.4, 26.2, 22.9, 14.3.
˚
performed with Mo Ka radiation (l) at 0.71073 A. Data reduction
22
21
was performed using the SAINT software, which corrects for Lp
1,2-Epoxydodecane . 1-Dodecene (852 mg, 5.0 mmol) in
-
2
and decay. The structure was solved by the direct method using
4.5 mL CH
2
Cl
2
; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in 4.5 mL
23
the SHELXS-97 program and refined by least squares method on
CH CN; CH
3
3
CO
3
H (7.65 g, 10%, 10.0 mmol) was added over
2
24
25
◦
F , SHELXL-97, incorporated in SHELXTL V5.10. Unit cell
dimensions were obtained with least-squares refinements, and all
structures were solved by direct methods with SHELXL-97. The
other non-hydrogen atoms were located in successive difference
30 min; reaction time: 3 min; reaction temperature: 0 C; workup
using petroleum ether (boiling point: 30–40 C) (2 ¥ 50 mL). Three
trials provided the product in 94% isolated average yield. H NMR
(300 MHz, CDCl
◦
1
3
) d 2.90 (m, 1H), 2.72 (dd, J = 4.0 and 5.0 Hz,
2
664 | Dalton Trans., 2010, 39, 2660–2666
This journal is © The Royal Society of Chemistry 2010

View Article Online
Table 4 Details of structure determination, refinement, and experimental parameters for complexes 4b–4d
4c
4
b
4d
Formula
C
811.67
Monoclinic
Pc
0.45¥ 0.15 ¥ 0.15
10.3766(19)
21.576(4)
9.2436(17)
90.00
115.806(2)
90.00
1863.2(6)
2
28
H
34
F
6
MnN
8
O
6
S
2
C
845.59
Monoclinic
P21/n
0.25¥ 0.20 ¥ 0.20
9.0524(11)
26.257(3)
15.0307(18)
90.00
97.368(2)
90.00
3543.2(7)
4
24
H
24
F
6
MnN10
O
10
S
2
28 33 6 9 8 2
C H F MnN O S
856.69
Orthorhombic
Pbca
0.50¥ 0.30 ¥ 0.20
19.677(5)
14.929(5)
25.509(5)
90.000(5)
90.000(5)
90.000(5)
7493(3)
Formula wt
Crystal system
Space group
Crystal size/mm
a/A˚
b/A˚
c/A˚
◦
a/
◦
b/
◦
g /
V/A˚
3
Z
8
-
3
D
c
/mg m
1.441
0.546
828
1.89–25.00
12744
1.585
0.588
1716
1.57–26.00
26327
1.519
0.552
3512
1.60–25.00
51351
-1
m/mm
F(000)
q range/
◦
Reflns. collected
Reflns. unique
5635
6890
6611
Parameters
Goodness-of-fit on F
530
1.073
0.0627, 0.1931
0.0655, 0.1966
0.418, -0.356
480
0.968
0.0620, 0.1519
0.1406, 0.1813
0.356, -0.365
489
1.044
0.0865, 0.2497
0.1199, 0.2868
1.700, -1.600
2
R
R
1
, wR
, wR
2
[I > 2s(I)]
1
2
[all data]
Max, min Dr/e A˚
-3
1
H), 2.43 (dd, J = 2.6 and 5.0 Hz, 1H), 1.51–1.24 (m, 18H), 0.88
) d 58.3, 52.7,
7.4, 32.7, 32.1, 29.8, 29.78, 29.70, 29.5, 26.2, 22.9, 14.4.
1H), 2.75 (dd, J = 3.3 and 4.9 Hz, 1H), 2.47 (dd, J = 4.2 and
5.1 Hz, 1H), 1.51–1.19 (m, 30H), 0.88 (t, J = 7.0 Hz, 3 H).
1
3
(
4
t, J = 7.0 Hz, 3 H). C NMR (75 MHz, CDCl
3
29
Methyl 9-(oxiran-2-yl)nonanoate . Methyl 10-undecenoate
26
1
,2-Epoxytetradane . 1-Tetradecene (1.04 g, 94% pure,
(
1
1.0 g, 5.0 mmol) in 4.5 mL CH
3
CN; catalyst 4d (21 mg, 2.5 ¥
CO H (7.65 g, 10%, 10.0 mmol)
-
2
5
4
3
.0 mmol) in 4.5 mL CH
2
Cl
2
; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in
-2
0 mmol) in 4.5 mL CH
3
CN; CH
3
3
mL CH
3
CN; CH
3
CO
3
H (7.65 g, 10%, 10.0 mmol) was added over
was added over 30 min; reaction time: 3 min; reaction temperature:
◦
0 min; reaction time: 3 min; reaction temperature: 0 C; workup
◦
◦
0
5
C; workup using petroleum ether (boiling point: 30–40 C) (2 ¥
◦
using petroleum ether (boiling point: 30–40 C) (2 ¥ 50 mL). Three
trials provided the product in 89% isolated average yield. H NMR
0 mL). Three trials provided the product in 89% isolated average
1
1
yield. H NMR (300 MHz, CDCl
3
) d 3.62 (s, 3H), 2.89 (m, 1H),
.71 (dd, J = 4.2, 4.7 Hz, 1H), 2.45 (m, 1H), 2.28 (t, J = 7.4 Hz,
H), 1.59–1.21 (m, 14H). C (75 MHz, CDCl ) d 174.3, 51.4, 52.5,
7.2, 34.1, 32.5, 29.3, 29.2, 29.1, 29.0, 25.9, 24.9. ESI-MS m/z 214
(
1
(
3
1
300 MHz, CDCl
H), 2.44 (dd, J = 3.0 and 5.1 Hz, 1H), 1.52–1.24 (m, 22H), 0.88
) d 52.4, 47.1,
2.5, 31.9, 29.7, 29.65, 29.64, 29.56, 29.55, 29.5, 29.4, 29.0, 22.7,
4.1.
3
) d 2.89 (m, 1H), 2.72 (dd, J = 4.2 and 5.0 Hz,
2
2
4
13
3
1
3
t, J = 6.8 Hz, 3 H). C NMR (75 MHz, CDCl
3
+
[
M + H] .
2
9
2
7
Ethyl
9-(oxiran-2-yl)nonanoate . Ethyl
10-undecenoate
1
,2-Epoxyhexadecane . 1-Hexadecene (1.19 g, 94% pure,
-
2
(1.10 g, 5.0 mmol) in 4.5 mL CH
3
CN; catalyst 4d (21 mg,
5
4
.0 mmol) in 4.5 mL CH
.5 mL CH
2
Cl
2
; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in
H (7.65 g, 10%, 10.0 mmol) was added
-
2
2
1
.5 ¥ 10 mmol) in 4.5 mL CH
3
CN; CH
3
CO H: (7.65 g, 10%,
3
3
CN; CH
3
CO
3
0.0 mmol) was added over 30 min; reaction time: 3 min; reaction
temperature: 0 C; workup using petroleum ether (boiling point:
30–40 C) (2 ¥ 50 mL). Three trials provided the product in 91%
isolated yield. H NMR (300 MHz, CDCl
H), 2.88 (m, 1H), 2.72 (dd, J = 4.1, 4.8 Hz, 1H), 2.44 (m, 1H),
2.27 (t, J = 7.3 Hz, 2H), 1.60–1.23 (m, 14H), 1.21 (t, J = 7.0 Hz,
H).
over 30 min; reaction time: 3 min; reaction temperature: room
temperature; workup using petroleum ether (boiling point: 30–
C) (2 ¥ 50 mL). Three trials provided the product in 83%
isolated average yield. H NMR (300 MHz, CDCl ) d 2.91–2.86
◦
◦
◦
40
1
1
3
) d 4.11 (t, J = 7.1 Hz,
3
2
(
1
m, 1H), 2.74 (dd, J = 3.7and 5.2Hz, 1H), 2.47(dd, J = 2.2, 5.2Hz,
1
3
H), 1.51–1.26 (m, 26H), 0.88 (t, J = 6.8 Hz, 3 H). C (75 MHz,
) d 52.3, 47.1, 32.5, 32.0, 29.7, 29.6 (several overlapped
peaks), 29.4, 25.9, 22.7, 14.1.
3
CDCl
3
4b
1
,2-Epoxycyclooctene . Cyclooctene (550 mg, 5.0 mmol) in
9.0 mL MeCN; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in 5 mL
H (7.6 g, 10%, 10.0 mmol) was added over
30 min; reaction time: 3 min; reaction temperature 0 C; workup
28
-2
1
,2-Epoxyoctadecane . 1-Octadecene (1.40 g, 90% pure,
-
2
5
4
.0 mmol) in 4.5 mL CH
.5 mL CH
2
Cl
2
; catalyst 4d (21 mg, 2.5 ¥ 10 mmol) in
MeCN; CH
3
CO
3
◦
3
CN; CH
3
CO
3
H (7.65 g, 10%, 10.0 mmol) was added
over 30 min; reaction time: 3 min; reaction temperature: room
using pentane (2 ¥ 40 mL). Three trials provided the product in
1
temperature; workup using petroleum ether (boiling point: 30–
92% isolated average yield. H NMR (300 MHz, CDCl
2.83 (m, 2H), 2.12–2.08 (m, 2H), 1.56–1.22 (m, 10H), C NMR
3
13
) d 2.87–
◦
40
C) (2 ¥ 50 mL). Three trials provided the product in 79%
1
isolated average yield. H NMR (300 MHz, CDCl
3
) d 2.91 (m,
(75 MHz, CDCl
3
) d 55.6, 26.5, 26.3, 25.6.
This journal is © The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 2660–2666 | 2665

View Article Online
Acknowledgements
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Financial support from National Science Foundation of China
1
(
Grant Nos. 20902004, 20802002 and 20832001) and Anhui
province (Grant Nos. 090416221 and KJ2009A130) is gratefully
acknowledged. We thank Ms Wenqian Geng for the help of X-ray
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1
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4
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