1. Molecular and Gold Nanoparticles Supported N-Heterocyclic Carbene Silver(I) Complexes – Synthesis, Characterization and Catalytic Applications
學 生 :王趙增
指導老師 : 于淑君 博士
2009 / 04 / 27
Department of Chemistry & Biochemistry
Chung Cheng University

2. N-Heterocyclic Carbenes
NHCs are strongerσ-donors than the most electron rich phosphine
- less likely to dissociate from the metal during the reaction
NHCs have come to replace phosphines in many organometallic and organic reactions
NHCs can be useful spectator ligands, tunable electronically and sterically
NHCs are most frequently prepared via deprotonation of the corresponding azolium salts

3. N-Heterocyclic Carbenes as Ligands
- In the early 90's NHC were found to have bonding properties similar to trialklyphosphanes( -PR3 ) and alkylphosphinates( -OP(OR)R2 ).
- compatible with both high and low oxidation state metals
- examples:
- reaction employing NHC's as ligands:
Herrmann, W. Angew. Chem. Int. Ed. 2002, 41,

4. The Applications of Ag(I) NHC
Silver(I)-Carbene Complexes as Carbene Transfer Agents
Addition of arenes to imines
Aza-Diels-Alder reaction
Asymmetric aldol reaction
Barbier-Grignard-type reaction

5. The First Silver(I)-Carbene Complexes
Arduengo.A.J,et.al. Organometallics 1993, 21,

6. Silver(I)-Carbene Complexes as Carbene Transfer Agents
Wang, H. M. J.; Lin, I. J. B. Organometallics 1998, 17,

7. Motivation
Using NHCs ligand to replace phosphine ligand in organomatallic catalysis.
-Immobilization of NHC- Ag(I) complexs onto Au Nanoparticles
Recyclable catalysts and their Applications in solvent-free system.
Developing a homogeneous catalyst for aldehyde alkyne and amine coupling.

8. Preparation of [Ag(hmim)2]PF6 Complex
Experimental
Preparation of [Ag(hmim)2]PF6 Complex

9. 1H NMR Spectra of [Hmim]HPF6, [Ag(hmim)2]PF6
*H2O
*DMSO
*H2O 2H 2H
*DMSO

10. 13C NMR Spectra of [Hmim]HPF6, [Ag(hmim)2]PF6
*DMSO C
*DMSO c

11. Change Temperature 1H NMR Spectra of [Ag(hmim)2]PF6
Temp.:250C
Temp.:100C H H

12. ESI-MS Spectrum of [Ag(hmim)2]PF6

13. Ionic Liquids As Stabilizing Agents for NPs
Addition of (a) HCl, (b) HBr, (c) HBF4, (d) HI,and (e) HPF6.
UV-vis absorption spectra corresponding to (a), (d), and (e) in photograph A.
Itoh, H.; Naka, K.; Chujo, Y. J. Am. Chem. Soc. 2004, 126,

14. Synthetic Strategy

15. Synthesis of Octanethiol Protected
Au-SR NPs
Particle size distribution
= 2.1 ± 1.12 nm
Brust, M,; Walker, M.; Bethell, D,;
Schiffrin, D, J.; Whyman, R.J.
Chem. Soc. Chem. Commun.
1994,

16. Nano-Gold Surface-Immobilized ILs

17. 1H, 31P, and 19F of Au NPs-Supported Ionic Liquid
31P NMR
19F NMR

18. TEM and UV Spectra of Au NPs-Supported Ionic Liquid
Particle size distribution
=3.1 ± 1.3 nm

19. Au NPs-Supported Ag(I) Complexes via Thiolated NHC Carbene Ligatior

20. Thiolated NHC Carbene Ligatior
1H, 31P, and 19F of Au NPs-Supported Ag(I) Complexes via
Thiolated NHC Carbene Ligatior
1 H
2 H
31P NMR
19F NMR

21. TEM of Au NPs-Supported Ag(I) Complexes via Thiolated NHC Carbene Ligatior

22. 1H NMR Spectra of Ligand, Molcular and Au Nanoparticles series

23. IR Spectra of Ligand & Au Nanoparticles series
Au-SR
IL-SH
Au-IL
Au-IL-Ag
imidazole H–C–C & H–C–N bending
1240 cm-1
1251cm-1
imidazole ν (ring stretching)
1560 cm-1
1571cm-1
-SH stretching

24. A3-coupling reactions
Have attracted much attention from organic chemists for the coupling products, propargylamines, which are major skeletons or synthetically versatile building blocks for the preparation of many nitrogen-containing biologically active compounds
J. Org. Chem. 1995, 60,

25. The First Silver-Catalyzed Three-Component Coupling of Aldehyde,
Alkyne, and Amine
Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003,

26. for the Three –Component Coupling
Proposed Mechanism
for the Three –Component Coupling
C-H activation
Silver(I)
Oxidation
Silver (I)
Reduction
Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003,

27. Solvents 1 Hr 2 Hr 4 Hr [Hmim]Br 28.96% 45.73% 8 Hr 69.63% 82.37%
[Hmim]PF6
78.58%
87.27%
94.78%
Propionitrile
91.31%
96.08%
97.68%
Acetonitrile
73.23%
82.57%
96.35%
DMF
30 min
38%
6 Hr
36.08%
37.59%
40%
1,4-dioxane
20%
11%
19%
23%
25%
Reaction conditions: Catalyst loading =1.5 mol%; carried out on a 1 mmol scale aldehyde/amine/alkyne = 1:1.2:1.5, 1000C, 1 mL of solvents.

28. Entry Time Yield(%) Paper Report cat. (AgI) 1 30 min 95 % 2 hr 96 % 2
93 %
79 % 3
8 hr
64.3 %
71 %
No test 4.
n.d 5.
92 %
Reaction conditions: Catalyst loading =1.5 mol%; carried out on a 2 mmol scale aldehyde/amine/alkyne = 1:1.2:1.5, 1000C, 1 mL of Propionitrile.

29. Entry Time Yield(%) Paper Report cat. (AgI) 1 30 min 95 % 2 hr 70% 2
70 %
90 %
60% 3
n.d
No test
Reaction conditions: Catalyst loading = 3 mol%; carried out on a 1mmol scale aldehyde/amine/alkyne = 1:1.2:1.5, 1000C, 1 mL of Propionitrile.

30. NHC–Ag(I) under solvent-free reaction conditions
Three-component coupling reactions catalyzed by a reusable PS-supported
NHC–Ag(I) under solvent-free reaction conditions
Li P. , Wang L. , Zhang Y. , Wang M. Tetrahedron Letters 49 (2008) 6650–6654

31. 1,2,4,5-tetramethylbenzene: 5 mg
d6-DMSO
0.25 : 0.13 = X :
X = mmol – lignad
×0.5 = mmol- metal center
0.0358/9 = mol/g
Au-[hmim]2AgPF6: 9 mg
1,2,4,5-tetramethylbenzene: 5 mg

32. 1 2 3 4 5 6 7 8 9
93%
97%
96%
95%
91%
90%
Reaction conditions: Catalyst loading = 20mol%;para-formaldehyde(1.0mmol),piperidine(1.1mmol) phenylacetylene(1.1mmol) at room temperature for 24 h

33. Conclusions 1.We have developed a method to successfully immobilize
(NHC)2AgPF6 onto surfaces of Au NPs was characterized
by 1H-NMR,IR,TEM.
2.The air- and water- stable catalyst [Ag(hmim)2]PF6 was characterized by 1H- and 13C NMR, LC-MS, IR.
3. We have successfully demonstrated the catalytic activity of the Ag(I) complex for three component (aldehyde, alkyne, and amine) coupling reaction.
4. The Au NPs- Ag(I) hybrid catalysts can be easily recovered and reused many times without significant loss of reactivity.

35. Immobilization of AgPF6(NHC) onto
Surfaces of Au-NPs
*H2O
*DMSO 2H H
*DMSO
*H2O 2H

36. IL-SH
Au-IL
Au-IL-Ag

37. 1 2
95%
92%
Li P. , Wang L. , Zhang Y. , Wang M. Tetrahedron Letters 49 (2008) 6650–6654