department of chemistry & biochemistry chung cheng university
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The Study of Catalytic Application of N-Heterocyclic Carbene Copper(I) Complex in Both Molecular and Supported Forms on
Huisgen Cycloaddition Reactions.
學生：莊雲婷指導教授：于淑君 博士
2010 / 05 / 03Department of Chemistry & Biochemistry
Chung Cheng University
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Phosphine Ligand
Phosphines are electronically and sterically tunable.
Expensive.
Air sensitive.
Metal leaching.
Chemical waste.
P P PPOO
O
P(Bu)3 P(OiPr)3 P(Me)3 P(o-tolyl)3
3
N-Heterocyclic Carbenes
NHCs are stronger σ-donor and weaker π-acceptor than the most electron rich phosphine,
NHCs can be useful spectator ligands, because they are sterically and electronically tunable.
NHCs can promote a wide series of catalytic reactions like phosphine.
NHCs have advantages over phosphines andoffer catalysts with better air-stability.
[M]
4
N-Heterocyclic Carbenes as Ligands- In the early 90's NHC were found to have bonding properties similar to trialklyphosphanes and alkylphosphinates.
- compatible with both high and low oxidation state metals
- examples:
- reaction employing NHC's as ligands:
Herrmann, W. Angew. Chem. Int. Ed. 2002, 41, 1290-1309.
Herrmann, W. A.; Öfele, K; Elison, M.; Kühn, F. E.; Roesky, P. W. J. Organomet. Chem. 1994, 480, C7-C9.
N NMe Me
WCO
COOCCOOC V
NHCCHNNHCCHN
Cl
ClTi ClCl
ClClNN
N N
Me Me
MeMe
Re OOO
Me
N NMe Me RuPCy3
Ph
NNMesMes
ClCl
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The Catalytic Applications of CuI
O-arylation of Phenols
Kharasch-Sosnovsky Reaction (Allylic Oxidations of Olefins)
S-arylation of Thiols
N-arylation of Amines (Buchwald-Hartwig Reaction)
Hydrosilylation of Ketones
Heck reaction
Oxidation of Alcohols
Substitution Reaction
Epoxidation Reaction
Reductive Aldol Reaction
1,3-dipolar cycloaddition
Carl Glaser. Berichte der deutschen chemischen Gesellschaft 1869. 2, 422–424.
Sonogashira Reaction
CuCl, O2
NH4OH, EtOH
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Drawbacks of Traditional Copper-Mediated Reactions
insoluble in organic solvents - heterogeneous
harsh reaction conditions - high temperatures around 200 °C - strong bases - toxic solvent such as HMPA - sensitive to functional groups on aryl halides - long reaction times - the yields are often irreproducible
structure not clear
Girard, C. Org. Lett., 2006. 1689-1692
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Catalyst supported onto Au NPs surface
soluble metal complex
functional groups
coordinationl ligands
spacer linker
catalyst
Au NPs have been known not only to possess solid surfaces resembling the (1 1 1) surface of bulk gold but also to behave like soluble molecules for their dissolvability, precipitability, and redissolvability.
Lin, Y.-Y; Tsai, S.-C.; Yu, S. J. J. Org. Chem. 2008, 73, 4920-4928.
Au NPs with controllable solubility
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Motivation
Using NHCs ligand to replace phosphine ligand inorganomatallic catalysis.
Base on economic standpoint, copper metal is cheaperthan palladium catalyst . - PdCl2 $4805.00(150g) ReagentPlus® (Aldrich) - CuCl $206.00(100g) ReagentPlus® (Aldrich)
Synthesis of NHC-Cu(I) complexes with well-defined structures.
Greener catalysis – microwave and solventless conditions.
Easily recovered and effectively recycled catalyst NHC-Cu(I) complexs by immobilization onto Au NPs.
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The First Isolable Carbene-CuI Complexes
Arduengo, A. J., III; Dias, H. V. R.; Calabrese, J. C.; Davidson, F. Organometallics 1993, 12, 3405-3409.
N
NH
t-BuOK
THF
N
N
N
N N
NCu+
CF3SO3-
M = Cu
Cu+-O3SCF3
THF
Cl
10
hmim = 1-hexyl-3-methylimidazolium
Preparation of CuI Complex Catalyst
Br
NN
65 oC, 12 hyield = 95 %
NNBr
CuI, t-BuONa
THF reflux, 24hyield = 96 %
(hmim)HBr(1)
NN
CuI(hmim)(2)
CuI
Preparation of (HS-hmim)HPF6
Br Br
NN
DMF, 65 oC, 16 hyield = 95 %
NN BrBr
1. CS(NH2)2, EtOH reflux, 16 h2. NaOH, 20oC, 3 min3. HCl, 20oC, 20 min
Yield = 70 %
NN SHBr
KPF6, H2O
0oC, 30 minyield = 53 %
NN SHPF6
(HS-hmim)HPF6(3)
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NN (CH2)6 S
Cl
2
+ HAuCl4NaBH4
NN (CH2)6 SH
Cl
Aun
Photographs of the obtained solutions of the 1-modified gold NPs after addition of (a) HCl (b) HBr (c) HBF4 (d) HI (e) HPF6.
Chujo.Y. J. Am. Chem. Soc. 2004, 126, 3026-3027
Synthesis of Gold Nanoparticles Modified with Ionic Liquid
(a) (e)
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TOAB = tetra-octyl ammonium bromideSR = Octane thiol
Au(SR) size : 2.4 0.39 nm
Synthesis of Octanethiol Protected Au NPs
HAuCl4 -4H2O
[CH3(CH2)7]4N+Br-
CHCl3, 1 h CHCl3. 15 min
NaBH4
H2O, 8 min S
SSAu
Au(SR) (4)
SH
SRTOAB
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IL = (S-hmim)(HPF6)
Au(SR)(IL) size : 2.04 0.7 nm
Synthesis of Au NPs Modified with Ionic Liquid
S NS
Au NPF6
S
N N
PF6Au(SR)m(IL)n
(5)
S
SSAu
Au(SR) (4)
NN SHPF6
(3)
THF, 40 oC, 4 h
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HS-CH2-
HS-CH2-
-CH3
-CH3
-CH3
DMSO
(4)
SCH2
CH3
S
H2C CH3
Au
CH3
H2C
HS
SHCH2
N N
PF6
(3)
SCH2 N
S
H2C
Au
CH3
NPF6(5)
CHCl3
CHCl3
DMSO
15
ILCu = S-hmim-CuCl
Au(SR)(IL)(ILCu) size : 1.63 0.32 nm
Synthesis of Au NPs Supported NHC-CuI complex
S NS
Au NPF6
S
N N
PF6Au(SR)m(IL)n
(5)
CuCl, t-BuONa
CH3CN, 60 oC, 24 hS N
SAu N
S
N
CuCl
Au(SR)x(IL)y(ILCu)z(6) N
CuCl
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-CH2-Hb
HbHa
-CH2-
-CH3
-CH3
*
*
#
#
H2O
H2O
DMSO
DMSO
NNH3CH2C
BrHa
Hb Hb(hmim)HBr
(1)
NNH3CH2C
CuI
Hb HbCuI(hmim)
(2)
1H NMR Spectra of (hmim)HBr (1) & (hmim)CuI (2)
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1H NMR Spectra of Au(SR)(IL) (5) & Au(SR)(IL)(ILCu) (6)
*d-DMSO
*d-DMSO#H2O
#H2O
HbHa
-CH2-
-CH3
Hb
-CH2-
-CH3
-CH3
-CH3
S H2C
N
SAu
CH3
N CH3
CuCl
HbHb
Au(SR)0.09(ILCu)1(6)
S H2C
N
SAu
CH3
N CH3
PF6
Ha
Hb Hb
Au(SR)0.17(IL)1(5)
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13C NMR Spectra of Au(SR)(IL) (5) & Au(SR)(IL)(ILCu) (6)
136.3 ppm
182.6 ppm
*DMSO
*DMSO
123.3 ppm121.9 ppm
123.6 ppm122.1 ppm
SN
SAu
C CN
C
PF6
H
Au(SR)0.17(IL)1(5) H H
S
N
SAu
C CN
CCuCl
Au(SR)0.09(ILCu)1(6) H
H
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IR Spectra of Ligand and NHC-CuI Series
CuI(hmim) (2)
(hmim)HBr (1)
Au(SR)(IL)(ILCu) (6)
Au(SR)(IL) (5)
4000 3500 3000 2500 2000 1500 10000
20
40
60
80
100
120
140
160
T (%
)
Wavenumber (cm-1)
(S-hmim)HPF6 (3)
1573
1636
1575
1677
1167
1229
1169
1218
2589
20
933
EDS and XPS of Au(SR)(IL)(ILCu) (6)
965 960 955 950 945 940 935 930
Inte
nsity
Binding Energy (eV)
932.8
2p3/2
2p1/2
Tubaro, C.; Tetrahedron. 2008. 4187-4195
Galtayries, A.; Bonnelle, J. -P. Surf. Interface Anal. 1995, 23, 171.
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R1NNN + R2N
NN
R1
R2
NN
NR1
R2
azide alkyne 1,4-disubstituted triazoles
1,5-disubstituted triazoles
+
The is a 1,3-dipolar cycloaddition between azide alkyne to give a 1,2,3-triazole
Rolf Huisgen was the first to understand this organic reaction at 1961.
K. Barry Sharpless and co-workers defined it as “a set of powerful, highly reliable, and selective reactions for the rapid synthesis of useful new compounds and combinatorial libraries” Sharpless, K. B. Angew. Chem., Int. Ed. 2001, 40, 2004-2021
Azide-Alkyne Huisgen Cycloaddition
Anke Cwiklicki, A. Arch. Pharm. Pharm. Med. Chem. 2004, 337, 156−163
Huisgen, R. .Angew. Chem. Int. Ed. 1961. 11. 633–645.
22Fokin, V. V.; Jia, G.; Lin, Z. J. Am. Chem. Soc. 2008. 130. 8923–8930
2 mol % cat.Rt, 30 min
Yield = 63-97 %
Tornøe, C. W.; Christensen, C.; Meldal, M. J. Org. Chem. 2002, 67, 3057-3064
(i) 2 eq 2-Azido-2-methylpropionic acid, 50 eq DIPEA, 2 eq CuI.(ii) 0.1 M NaOH (aq).
Azide-Alkyne Huisgen Cycloaddition
23
Nolan, S. P. Angew. Chem. Int. Ed. 2008, 47, 8881 –8884
TOF(h-1)
33322255062
2022
180
66389
37.5394
Reported NHC-CuI Catalytic Huisgen Cycloaddition
[a] The conversion (determined by GC) is an average of the values for at least two independent experiments.
24
Reported Mechanism for Azide-Alkyne Huisgen Cycloaddition
Nolan, S. P. Angew. Chem. Int. Ed. 2008, 47, 8881 –8884
25
(Hmim)CuI (2) Catalysis Huisgen Cycloaddition – Solvent Effect
Condition: Benzyl azide = 1 mmol, phenyl acetylene = 1.2 mmol. solvent = 0.25 mL, RT, 1 mol% (hmim)CuI. The conversion is determined by 1H NMR
26
(Hmim)CuI (2) Catalysis Huisgen Cycloaddition
Nolan, S. P. Angew. Chem. Int. Ed. 2008, 47, 8881 –8884
Condition: Benzyl azide = 1 mmol, phenyl acetylene = 1.2 mmol. solvent = 0.25 mL, RT, 0.05 mol% (hmim)CuI. The conversion is determined by 1H NMR
TOF(h-1)
333 2225 5062
27Condition: azide = 1 mmol, phenyl acetylene = 1.2 mmol. neat, RT, 1 mol% (hmim)CuI. The conversion is determined by 1H NMR
(Hmim)CuI (2) Catalysis Huisgen Cycloaddition
28
(Hmim)CuI (2) Catalysis Huisgen Cycloaddition
Condition: azide = 1 mmol, 1-nonyne = 1.2 mmol. neat, RT, 1 mol% (hmim)CuI. The conversion is determined by 1H NMR
29Condition: azide = 1 mmol, alkyne = 1.2 mmol. CH3CN = 0.25 mL, RT, 1 mol% (hmim)CuI. The conversion is determined by 1H NMR
(Hmim)CuI (2) Catalysis Huisgen Cycloaddition
30Wang, L. Tetrahedron. 2008. 64. 10825–10830
R2N
NN
R1
R2
N3 R1 +neat
1 mol %
N
NCuI
SiO2
Conditions: organic azide (1 mmol), alkyne (1 mmol), SiO2–NHC–Cu(I) (1 mol %). B Isolated yields.C At 80 oC for 24 h.
+
N3
NN
NR1
R2
1 mol %
RT , naet, 30 min
Cycle Yield(%)b Cycle Yield(%)b
1 93 6 92
2 93 7 90
3 91 8 90
4 92 9 88
5 89 10 87
N-Heterocyclic Carbenes CuI Supported on SiO2
TOF(h-1)=186
1.Structurally undefined
2.Quantitative
NHC-CuI by ICP-Mass
31
Determine CuI contents of Au(SR)(IL)(ILCu) (6)
I
H3COH
H
HH
S
N
SAu
CH3
N
CuCl
HH
Au(SR)0.09(ILCu)1(6)
2H2H 2H
3H
ILCu : iodoanisole = (1-0.1648) : 0.1648 = Cu : 2.245 x 10-6
Cu = 4.068 x 10-6 molILCu : SR = 0.8352 : 0.1080 = 1:0.13
d6-DMSO
Au(SR)(ILCu) 8 mg
4-iodoanisole
32
+N3N
NN
NHC-CuI Catalysis Huisgen Cycloaddition
Condition: Benzyl azide = 2 mmol, phenyl acetylene = 2.4 mmol. solvent = 0.5 mL. Yield determined by 1H NMR. (a) conversion is traced. (b) conversion is detected after reaction quenched. (c) 20 hr. (d) 16 h
r
33
Using Microwave System to Catalysis Huisgen Cycloaddition
microwave thermal
Kappe, C. O. Angew. Chem. Int. Ed. 2004, 43, 6250-6284.
Solvent Time(min) Conversion (%)
[Bmim][Br] 0.5 65
DMSO
1.5 4
2 24
3 99
CH3CN0.5 8
1 54
+
N3
1 mol % Au(SR)0.19(IL)0.57(ILCu)1 (6)
600 W
NN
N
Conditions: Benzyl azide (0.8 mmol), alkyne (0.96 mmol), Solvent = 0.15 mL. Conversion detected by 1H NMR
34
Conclusions
We have successful synthesis Complex 6 , and characterized by 1H- and 13C-NMR, TEM, IR, EDS and XPS.
We have successfully demonstrated the catalytic activity of the CuI complex for theHuisgen cycloaddition.
In the future, we would try to use Au-NHC-CuI
for the recycling test on Huisgen cycloaddition.
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