An efficient and recyclable catalyst for N-Alkylation of amines and β-alkylation of secondary alcohols with primary alcohols: Sba-15 supported N-Heterocyclic carbene iridium complex

Article abstract of DOI:10.1002/adsc.201200732

A mesoporous silica (SBA-15)-supported pyrimidine-substituted N-heterocyclic carbene iridium complex was prepared and used as a catalyst for both environmentally friendly N-alkylation of amines and β-alkylation of secondary alcohols with primary alcohols. The structure of the supported iridium catalyst was characterized by Fourier transform infrared (FT-IR), ¹³C and ²⁹Si solid-state nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), iridium K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopic analyses which demonstrated that the coordination environment of the iridium centre and the 3-dimensional- hexagonal pore structure of SBA-15 were retained after the immobilization. The catalyst was found to be highly efficient for both kinds of reaction on a wide range of substrates under mild conditions. Moreover, the supported iridium catalyst was obviously superior to the unsupported one in the N-alkylation of aniline and β-alkylation of 1-phenylethanol with benzyl alcohol as substrate, which indicated that not only the iridium complex moiety but also the support material contributed to the catalytic activity of the supported iridium catalyst in these reactions. The supported iridium catalyst can be easily recycled by simple washing without chemical treatment, and exhibited excellent recycling performance without notable decrease in catalytic efficiency even after twelve test cycles for N-alkylation of aniline with benzyl alcohol, nine cycles for N-alkylation of different amines with different alcohols, and eight cycles for β-alkylation of 1-phenylethanol with benzyl alcohol, respectively. Copyright

Full text of DOI:10.1002/adsc.201200732

FULL PAPERS
DOI: 10.1002/adsc.201200732
An Efficient and Recyclable Catalyst for N-Alkylation of Amines
and b-Alkylation of Secondary Alcohols with Primary Alcohols:
SBA-15 Supported N-Heterocyclic Carbene Iridium Complex
Dong Wang,+a,b Xu-Qing Guo,+a Chen-Xi Wang,a Ya-Nong Wang,a Rui Zhong,a
Xiao-Han Zhu,a Li-Hua Cai,a Zi-Wei Gao,b,* and Xiu-Feng Houa,*
a
Department of Chemistry, Fudan University, Shanghai 200433, Peopleꢀs Republic of China
E-mail: xfhou@fudan.edu.cn
b
School of Chemistry and Materials Science, Shaanxi Normal University, Xi’an 710062, Peopleꢀs Republic of China
E-mail: zwgao@snnu.edu.cn
+
These authors contributed equally to this work.
Received: August 16, 2012; Revised: January 15, 2013; Published online: March 20, 2013
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201200732.
Abstract: A mesoporous silica (SBA-15)-supported ported iridium catalyst was obviously superior to the
pyrimidine-substituted N-heterocyclic carbene iridi- unsupported one in the N-alkylation of aniline and
um complex was prepared and used as a catalyst for b-alkylation of 1-phenylethanol with benzyl alcohol
both environmentally friendly N-alkylation of as substrate, which indicated that not only the iridi-
amines and b-alkylation of secondary alcohols with um complex moiety but also the support material
primary alcohols. The structure of the supported iri- contributed to the catalytic activity of the supported
dium catalyst was characterized by Fourier transform iridium catalyst in these reactions. The supported iri-
infrared (FT-IR), 13C and 29Si solid-state nuclear dium catalyst can be easily recycled by simple wash-
magnetic resonance (NMR), small-angle X-ray scat- ing without chemical treatment, and exhibited excel-
tering (SAXS), transmission electron microscopy lent recycling performance without notable decrease
(TEM), iridium K-edge X-ray absorption near-edge in catalytic efficiency even after twelve test cycles
structure (XANES) and extended X-ray absorption for N-alkylation of aniline with benzyl alcohol, nine
fine structure (EXAFS) spectroscopic analyses which cycles for N-alkylation of different amines with dif-
demonstrated that the coordination environment of ferent alcohols, and eight cycles for b-alkylation of 1-
the iridium centre and the 3-dimensional-hexagonal phenylethanol with benzyl alcohol, respectively.
pore structure of SBA-15 were retained after the im-
mobilization. The catalyst was found to be highly ef- Keywords: b-alkylation of secondary alcohols; immo-
ficient for both kinds of reaction on a wide range of bilization; iridium; N-alkylation of amines; N-heter-
substrates under mild conditions. Moreover, the sup- ocyclic carbenes
Introduction
ploying Ir[4] or Ru[4c–g,5] complexes, for example,
[Cp*IrCl2]2 (Cp*=pentamethylcyclopentadienyl
(p-cymene)Cl2]2, Cp*Ir(NHC) (NHC=N-
Recently, much attention has been focused on the anion), [Ru
G
ACHTUNGTRENNUNG
À
strategy of redox processes in the formation of C N heterocyclic carbene) and Ir(P, N ligand) have been
À
or C C bonds through the use of alcohols to replace developed. Although they are very efficient catalysts,
toxic halides.[1] In addition, reactions such as N-alkyla- separating the products from the reaction mixtures
tion of amines with alcohols and b-alkylation of sec- still remains a challenge. Furthermore, the lack of re-
ondary alcohols with primary alcohols produce water cyclability of these homogenous catalysts hindered
as sole by-products and are thus environmentally- their applications. In the last few years, heterogeneous
benign.[2] Since the first homogeneous catalysts for catalysts such as Pd/MgO or Fe2O3,[6] Ag/Mo or Ag/
the N-alkylation of amines were introduced by Grigg Al2O3,[7] Au/TiO2 and CuAl-HT (copper-aluminum
[8]
and Watanabe in 1981,[3] various catalytic systems em- hydrotalcite)[9] were also developed for the N-alkyla-
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Dong Wang et al.
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tion of amines. However, most of them required Results and Discussion
harsh reaction conditions. Thus, we are interested in
the immobilization of metal complexes on support The reaction of N-(2-pyrimidyl) imidazole and 3-iodo-
surfaces which combines the advantages of homoge- propyl(trimethoxy)silane affords the corresponding
neous and heterogeneous catalysis.
pyrimidine imidazolium salt. Then, the SBA-15-sup-
A recent computational study on the mechanism of ported N-heterocyclic carbene iridium complex 1 is
N-alkylation of amines with alcohols catalyzed by obtained by in situ transmetalation from the silver
Cp*Ir shows three sequential steps: (i) metal-cata- carbene complex of the imidazolium salt with
lyzed oxidation of alcohols to aldehydes, (ii) conden- [Cp*IrCl2]2, followed by the addition of SBA-15
sation of the aldehydes with amines to form imines, (Scheme 1). For comparison, pyrimidine-substituted
and (iii) metal-catalyzed reduction of the imines to N-heterocyclic carbene chelated iridium complex 2
the final products, secondary amines.[4a] It is crucial (Scheme 2) was synthesized according to a literature
that the same catalyst has to dehydrogenate alcohols method.[4c]
and hydrogenate imines. Dehydrating agents in the
In the FT-IR spectrum of 1 (see Supporting Infor-
catalytic system are needed to promote the condensa- mation, Figure S1), the characteristic bands of SBA-
tion of aldehydes with amines. Mesoporous silica 15 around 1085 and 462 cmÀ1 for n
ACTHNUTRGENN(UG Si O) and dACHTUNGTRENNUNG(Si
À
À
(SBA-15) provides an ideal support for homogenous O) are maintained and the band around 937 cmÀ1 as-
À
catalyst immobilization owing to the ordered struc- signed to Si OH stretching of silanols on the surface
tures, very high surface area, as well as uniform and almost disappears.[12] These indicate that the Ir com-
large pore diameter.[10] Several catalytic processes plex is tethered onto SBA-15 surface, which is further
using SBA-15 immobilized complexes as catalysts confirmed by solid state NMR spectra. The 29Si CP/
were developed.[11] However, in these catalysts, SBA- MAS NMR spectrum of 1 (see the Supporting Infor-
15 just plays a support role, but does not promote the mation, Figure S4) exhibited strong signals (À101.3,
reactions.
À109.9 ppm) originating from network structures of
We designed a silica-supported catalyst, consisting SBA-15 and weak signals (À50.2, À57.7 ppm) derived
of a Cp*IrACHTUNGTRENNUNG(NHC) moiety, which proved to be efficient from silyl ether groups of the iridium complex
for the N-alkylation of amines with alcohols and mes- moiety.[13] In the solid-state 13C CP/MAS NMR spec-
oporous silica (SBA-15) providing water-locking func-
tion. Herein, we describe the synthesis and characteri-
zation of SBA-15-immobilized N-heterocyclic carbene
iridium complex 1, and its application in catalyzing
both the N-alkylation of amines with alcohols and the
b-alkylation of secondary alcohols with primary alco-
hols with remarkably high reactivity and exceptional
recycleability. In addition, the support material, SBA-
15, in catalyst 1 obviously promots the mentioned re-
actions as has now been proved.
Scheme 2. Ir complex 2.
Scheme 1. Synthesis of SBA-15 supported Ir complex 1. Reaction conditions: (a) toluene, reflux, 24 h; (b) Ag2O, CH2Cl2,
room temperature, 16 h; then [Cp*IrCl2]2, room temperature, overnight; (c) SBA-15, toluene, reflux, 48 h.
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An Efficient and Recyclable Catalyst for N-Alkylation of Amines and b-Alkylation of Secondary Alcohols
Figure 1. The 13C CP/MAS NMR spectrum of SBA-15-supported Ir complex 1.
Figure 2. Normalized Ir L3 edge XANES spectra (a) and Fourier transform EXAFS spectra (b) for 1, 2, and 3 (catalyst recy-
cled from b-alkylation of 1-phenylethanol with benzyl alcohol for eight times).
trum Figure 1), signals at 8 and 92 ppm indicate the of the supported Ir complex 1 has the same coordina-
present of the Cp* ring while resonances at 158– tion environment as complex 2. The SAXS patterns
116 ppm and 58–16 ppm are attributed to aromatic (Figure 3) of 1 show one similar intense d100 diffrac-
carbons and aliphatic carbons respectively, which are tion peak along with two similar weak diffraction
consistent with those of complex 2. The loading level peaks (d110, d200), suggesting that the dimensional-hex-
of the immobilized iridium was measured to be agonal pore structure observed in SBA-15 is pre-
3.26:96.74 (Ir:Si atomic%) by EDS (see Supporting served after the immobilization, which can also be
Information, Figure S2).
demonstrated by the TEM image (Figure 4). All these
From the Ir L3 edge XANES and EXAFS spectra characterization findings of the supported Ir complex
(Figure 2) of 1 and 2, it is clear that the metal centre 1 confirm the retention of both its original coordina-
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Dong Wang et al.
Table 1. N-Alkylation of amines with alcohols.[a]
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Entry
1
Amine
Alcohol
Yield [%][b]
93
80
0
2[c]
3[d]
4
93
5
6
94
78
Figure 3. The SAXS patterns for SBA-15 (a), 1 (b) and 3
(c).
7
52
94
99
91
8
9
10
Figure 4. TEM images of 1 (a) and 3 (b) viewed along the
[100] direction.
11
12
13
89
81
90
70
tion environment of the Ir centre and the dimension-
al-hexagonal pore structure of SBA-15.
With the well-defined supported Ir complex 1 in
hand, its abilities to catalyze the N-alkylation of
amines (Table 1) and the b-alkylation of secondary al-
cohols (Table 2) with alcohols were examined. The
unsupported Ir complex 2 and SBA-15 were also used
in these catalytic processes for comparison. For the
N-alkylation of aniline with benzyl alcohol (Table 1,
entries 1–3) and the b-alkylation of 1-phenylethanol
with benzyl alcohol (Table 2, entries 1–3), 1 was obvi-
ously superior to 2 and SBA-15 alone did not work,
which indicates that the Ir complex moiety in catalyst
14
[a]
Reaction conditions: alcohol (1.0 mmol), amine
(1.1 mmol), 1 (Ir: 1.5 mol%), NaHCO3 (0.5 mmol), tolu-
ene (0.5 mL), 1108C, 48 h.
[b]
[c]
[d]
Isolated yield.
2 (1.5 mol%) as catalyst.
SBA-15 as catalyst.
1 is crucial and the support material SBA-15 also transformation of substituted anilines with substituted
plays an important role in promoting the reactions. benzyl alcohols, with both electron-poor and electron-
Results obtained from the N-alkylation of various rich groups, afforded the corresponding secondary
amines with primary and secondary alcohols are sum- amines in excellent yields (Table 1, entries 8–11). Ali-
marized in Table 1. Benzyl alcohols with electron- phatic (Table 1, entries 12 and 13) and heterocyclic
poor and electron-rich groups (Table 1, entries 1, 4, amines (Table 1, entry 14), which are difficult to react,
and 5) and secondary alcohol (Table 1, entry 6) react could also participate smoothly to generate the corre-
with aniline to give the desired products in high sponding amines in good to excellent yields.
yields, even an aliphatic alcohol (Table 1, entry 7)
We found that 1 was surprisingly versatile, it was
gives a moderate yield in the same conditions. The also efficient for the b-alkylation of secondary alco-
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An Efficient and Recyclable Catalyst for N-Alkylation of Amines and b-Alkylation of Secondary Alcohols
Table 2. b-Alkylation of secondary alcohols with primary al-
hols with primary alcohols and the desired products
were obtained in moderate to excellent isolated yields
(Table 2). Aromatic methyl secondary alcohols react
with aromatic primary alcohols to give the desired
products in excellent yields (Table 2, entries 1, 4–8),
with both electron-poor and electron-rich groups. The
reactions of 1-(naphthalen-2-yl)ethanol or 4-phenyl-
butan-2-ol with benzyl alcohol (Table 2, entries 9 and
10) and 1-phenylethanol with n-hexyl alcohol
(Table 2, entry 11), which are difficult to react, give
the corresponding products in moderate to good
yields.
Recycling studies for the two reactions were then
performed, and the results are shown in Figure 5.
After being simply filtered and washed with CH2Cl2,
catalyst 1 could be used repetitively twelve times for
the N-alkylation of aniline with benzyl alcohol and
eight times for the b-alkylation of 1-phenylethanol
with benzyl alcohol without significant decreases in
isolated yields, from 93 to 83% and 94 to 82%, re-
spectively.
cohols.[a]
Entry Secondary alcohol Primary alcohol Yield [%][b]
1
93
75
0
2[c]
3[d]
4
93
In order to compare the activity of the fresh and
reused catalysts, we performed kinetic experiments
for the N-alkylation of aniline with 4-methylbenzyl al-
cohol and the b-alkylation of 1-(p-tolyl)ethanol with
benzyl alcohol by using gas chromatography
(Figure 6). The kinetic profiles show that both the
fresh and reused catalysts have induction periods in
the two reactions and the reused catalyst has longer
induction periods in comparison to the fresh one.[14]
We also notice that the activity of the fresh catalyst is
slightly lower in the early stage but higher after the
induction period than that of the fresh one.
From XANES spectra (Figure 2), there is no appar-
ent difference between the fresh catalyst 1 and the re-
covered catalyst 3, which indicates that most Ir in 3
retains the same electronic structure as 1. From the
EXAFS spectra (Figure 2), the intensity of the main
peak at ~1.6 ꢂ of 3 is lower than that of 1. This can
be attributed to the loss and decomposition of the cat-
alyst, which are unavoidable after the 8 cycles of reac-
tion. This is a common phenomenon in supported or-
ganometallic catalysts. On the other hand, from the
TEM observation of 3 (Figure 4), there is no obvious
change in the morphology and size compared with
fresh catalyst 1, which is also confirmed by the SAXS
pattern (Figure 3).
5
6
7
8
92
94
91
90
9
61
70
10
In order to further investigate the reusability of cat-
alyst 1, we used different combinations of substrates
in nine recycle tests of the N-alkylation of amines
with alcohols. As shown in Table 3, over 90% isolated
11
58
[a]
Reaction conditions: secondary alcohol (1.0 mmol), pri-
mary alcohol (1.1 mmol),
(1.0 mmol), toluene (0.5 mL), 1108C, 24 h.
Isolated yield.
2 (1.5 mol%) as catalyst.
SBA-15 as catalyst.
1 (Ir: 1.5 mol%), KOH yields were achieved in all of the sequential runs,
which supports that the SBA-15-supported Ir complex
1 possesses extremely high efficiency and excellent re-
cycle ability in the N-alkylation of amines with pri-
mary alcohols.
[b]
[c]
[d]
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Dong Wang et al.
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Figure 5. Yields in the recycling of 1 for the N-alkylation of aniline with benzyl alcohol (a) and b-alkylation of 1-phenyletha-
nol with benzyl alcohol (b). Reaction conditions: the same with those shown in Table 1 and Table1 2.
Figure 6. Kinetic profiles for N-alkylation of aniline with 4-methylbenzyl alcohol (a) and b-alkylation of 1-(p-tolyl)ethanol
with benzyl alcohol (b). Reaction conditions: catalyst 1 (20 mg), toluene (0.1 mL), and dodecane (0.05 mmol) as an internal
standard. For (a) aniline (0.22 mmol), 4-methylbenzyl alcohol (0.20 mmol), NaHCO3 (0.10 mmol); (b) 1-(p-tolyl)ethanol
(0.20 mmol), benzyl alcohol (0.22 mmol), KOH (0.20 mmol).
An experiment was carried out to verify whether
the observed catalysis was due to the heterogeneous
catalyst 1 or the leached iridium species in solution.
Table 3. Reusability of 1 for N-alkylation of amines reaction
The reaction of 1-phenylethanol with benzyl alcohol
was completely terminated by the removal of 1 from
the reaction mixture after 50% conversion of 1-phe-
nylethanol under the conditions as in Table 2 entry 1.
Further treatment of the filtrate under the same reac-
tion conditions did not improve the yield. Moreover,
ICP analysis of the filtrate confirmed that the Ir con-
tent was below the detection limit (<0.10 ppm).
These findings indicate that the catalysis is heteroge-
neous.
with different substrates.[a]
Run[b]
R1
R2
Yield [%][c]
1
2
3
4
5
6
7
8
9
C6H5
C6H5
C6H5
C6H5
C6H5
4-ClACTHNGUETRN(NUG C6H4)
4-MeO
C6H5
93
94
90
91
93
92
91
95
93
4-Cl
ACHTUNGTRENNUNG(C6H4)
ACHTUNGTRENNUNG
C6H5
C6H5
C6H5
4-MeOACHTUNGTRENNUNG(C6H4)
ACHTUGNTERN(NUGN C6H4)
Conclusions
4-Cl
N
4-Cl
N
C6H5
C6H5
In summary, we have successfully prepared a mesopo-
rous SBA-15-supported pyrimidine-substituted N-het-
erocyclic carbene iridium complex 1, in which the in-
tegrity of both the organometallic moiety and the in-
[a]
Reaction conditions: see Table 1.
The catalyst used was recycled from the last entry.
Isolated yield.
[b]
[c]
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An Efficient and Recyclable Catalyst for N-Alkylation of Amines and b-Alkylation of Secondary Alcohols
EXAFS data were performed using the program ARTE-
organic support remain unchanged. The well-defined
catalyst 1 was obviously superior to Ir-catalyzed ho-
mogenous system for the clean and atom-efficient N-
alkylation of amines with alcohols and b-alkylation of
secondary alcohols with primary alcohols in the same
conditions. That the support material SBA-15 in cata-
lyst 1 also promotes the mentioned reactions was
proven. It must be noted that the catalyst could be re-
covered by simple filtration and used repetitively for
twelve times (N-alkylation of aniline with benzyl alco-
hol) and eight times (b-alkylation of 1-phenylethanol
with benzyl alcohol) without significant loss of its cat-
alytic activity. Furthermore, the use of recycled 1 for
N-alkylation reactions with different substrates also
produces the desired products in high yields. The fact
that the integrity and bifunctionality of both the or-
ganometallic moiety and the inorganic support are
maintained nicely in consecutive catalysis runs meets
the objective set to merge the properties of a homoge-
neous and a heterogeneous catalytic system into one
sustainable hybrid catalyst system.
MIS.[17] A gas chromatography-mass spectra (Thermo Focus
ISQ) was also used.
Preparation of 1A
To a 50-mL Schlenk tube containing 10 mL of toluene, was
added N-(2-pyrimidyl)imidazole (62 mg, 0.42 mmol) and 3-
iodopropyl(trimethoxy)silane[18] (121 mg, 0.42 mmol). The
mixture was refluxed for 24 h, followed by the removal of
the solvent using a rotary evaporator. Addition of n-hexane
(10 mL) gave the product as an oily brown solid. Solvent
was decanted and the product was washed with ether several
1
times and dried in vacuum; yield: 174 mg (95%). H NMR
(CDCl3): d=10.37 (s, 1H, N-CH-N), 8.89 (d, J=4.8, 2H,
Hpyrimidine), 8.24 (s, 1H, imidazolebackbone), 7.91 (s, 1H, imida-
zolebackbone), 7.61 (m, 1H, Hpyrimidine), 4.71 (d, 2H, NCH2 of
silane), 3.55 (s, 9H, OCH3), 2.00 (m, 2H, CH2 of silane),
0.72 (m, 2H, SiCH2 of silane); 13C NMR (100 MHz, CDCl3):
d=159.74, 147.23, 135.07, 124.13, 122.40, 118.69, 52.78,
50.77, 23.93, 5.68; HR-MS (ESI+): m/z=309.20, calcd. for
[1AÀI]+: 309.14.
Preparation of 1B
The imidazolium iodide 1A (170 mg, 0.39 mmol) was dis-
solved in CH2Cl2 (10 mL) and added to a Schlenk vessel
containing activated 3ꢂ molecular sieves (50 mg) and Ag2O
(55 mg, 0.23 mmol). The reaction mixture was refluxed in
the absence of light for 12 h and filtered, after cooling to
room temperature, into a 50-mL Schlenk vessel. [Cp*IrCl2]2
(81 mg, 1.0 mmol) was added, and the reaction mixture was
stirred at room temperature in the absence of light for 6 h.
After filtration, the filtrate was concentrated under vacc-
uum, the resulting solid was purified by column chromatog-
raphy on silica gel (MeOH/CH2Cl2 =1/20) to afford a dark
yellow solid 1B; yield: 156 mg (78%). 1H NMR (CDCl3):
d=9.23 (m, 1H, Hpyrimidine), 8.94 (m, 1H, Hpyrimidine), 8.09 (s,
1H, imidazolebackbone), 7.92 (s, 1H, imidazolebackbone), 7.62 (m,
1H, Hpyrimidine), 4.91 (m, 2H, CH2N), 3.58 (s, 9H, OCH3),
2.13 (m, 2H, CH2), 1.89 (s, 15H, HCp*), 0.70 (m, 2H, CH2Si);
13C NMR (100 MHz, CDCl3): d=165.0, 160.8, 160.5, 157.1,
124.5, 122.2, 117.8, 92.7, 52.8, 50.7, 29.6, 24.4, 9.71, 6.31; HR-
MS (ESI+): m/z=478.18, calcd. for [1B-Cl]+: 478.22.
Experimental Section
All manipulations were carried out under a nitrogen atmos-
phere using standard Schlenk techniques unless otherwise
stated. Solvents were distilled under nitrogen from sodium
benzophenone (hexane, diethyl ether, toluene) or calcium
hydride (dichloromethane), and methanol was distilled over
Mg/I2. The starting materials 2-(1-imidazolyl)pyrimidine[15]
[16]
and [Cp*IrCl2]2 were synthesized according to the litera-
ture procedures. Other chemical reagents were obtained
from commercial sources and used without further purifica-
tion. FT-IR spectra were recorded on a Nicolet AVATAR-
360 IR spectrometer using KBr discs in the range of 4000–
400 cmÀ1. SEM analyses and EDS patterns were performed
with a JEOL JSM-6380LV instrument. TEM studies were
performed on a JEOL JEM2010 electron microscope, oper-
ated at an acceleration voltage of 200 kV. The SAXS pat-
terns were recorded with a Bruker D4 powder X-ray diffrac-
tometer using Cu Ka radiation (40 kV, 40 mA). Nuclear
magnetic resonance (NMR) spectra were recorded using
Bruker spectrometers operating at 400 MHz (1H) and
100 MHz (13C) in CDCl3. Solid state 13C and 29Si CP MAS
NMR spectra were recorded at 100.6 MHz using a Bruker
AV-400 spectrometer. EI mass spectra were recorded by an
Agilent 5973N mass spectrometer. High resolution mass
spectrometry (HR-MS) was performed using the Waters Mi-
cromass GCT Permier. Ir K-edge X-ray absorption near-
edge structure (XANES) and spectroscopic signal extended
X-ray absorption fine structure (EXAFS) spectroscopic
analyses were performed at room temperature in transmis-
sion mode using ion chambers filled with N2/Ar at beam
line BL14W1 of the Shanghai Synchrotron Radiation Facili-
ty (SSRF), China. The station was operated with an Si
(311) double crystal monochromator. During the measure-
ment, the synchrotron was operated at an energy of 3.5 GeV
and a current between 150–210 mA. Data processing was
performed using the program ATHENA. All fits to the
Preparation of 1
A suspension of 1B (154 mg, 0.30 mmol) and SBA-15 (1.0 g)
in toluene (10 mL) was refluxed for 48 h, the solid was fil-
tered and washed sequently with CH2Cl2, ethanol and ether,
and then vacuum-dried to give a bright yellow soild. 13C CP-
MAS NMR (100.6 Hz, solid state): d=158, 149, 133, 124,
120, 116, 92, 58, 50, 26, 16, 8; 29Si CP-MAS NMR (100.6 Hz,
solid state): d=À50.2, À57.7, À101.3, À109.9.
Preparation of 2
This was prepared according to a literature procedure.[4c]
1H NMR (CDCl3): d=8.88–8.84 (m, 2H), 7.86 (d, 1H), 7.63
(t, 1H), 7.32 (m, 1H), 4.30–4.28 (m, 2H), 1.92 (m, 2H), 1.80
(s, 15H), 1.40–1.35 (m, 2H), 0.98 (t, 3H); 13C NMR
(126 MHz, CDCl3): d=159.97, 152.53, 136.99, 123.91, 122.37,
118.80, 93.00, 50.99, 32.50, 19.68, 13.72.
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References
General Procedure for N-Alkylation of Amines with
Primary Alcohols
À
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General Procedure for Recycling Use of the
Supported Catalyst 1
According to the general procedure for the N-alkylation of
amines or b-alkylation of secondary alcohols with premary
alcohols, the first run reaction was carried out. After com-
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Supporting Information
The Supporting Information for this article contains IR
spectra of 1 and 2, EDS patterns of 1, TEM images of 1 and
3 viewed along the [001] directions, and NMR spectra of
the products.
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Acknowledgements
Financial support by the National Science Foundation of
China (grant nos. 20871032, 20971026, 21271047, 21041004),
the Program for New Century Excellent Talents in University
of China (NCET-07-0528), the Fundamental Research Funds
for the Central Universities (GK200902001, GK261003), the
Shanghai Leading Academic Discipline Project (project no.
B108), and Shanghai Key Laboratory Green Chemistry and
Chemical Precess is gratefully acknowledged. The authors
thank Prof. Dongyuan Zhao (Fudan University) for donating
SBA-15 and beamline BL14W (Shanghai Synchrotron Radia-
tion Facility) for providing the beam time.
1124
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