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 / 07 / 20 Department of Chemistry & Biochemistry Chung Cheng University

2 N-Heterocyclic Carbenes (NHC) 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 L-type two electrons

3 N-Heterocyclic Carbenes as Ligands -In the early 90's NHC were found to have bonding properties similar to trialklyphosphanes( -PR 3 ) and alkylphosphinates ( -OP(OR)R 2 ). -compatible with both high and low oxidation state metals -examples: -reaction employing NHC's as ligands: Herrmann, W. Angew. Chem. Int. Ed. 2002, 41, Herrmann, W. A.; Öfele, K; Elison, M.; Kühn, F. E.; Roesky, P. W. J. Organomet. Chem. 1994, 480, C7-C9.

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 and The First Silver(I)-Carbene Complexes and Carbene-Copper(I) Complexes Arduengo A.J. et al. Organometallics 1993, 21, Linear di-coordination

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

7 The trend of the bond energies for the metal fragments is AuCl > CuCl > AgCl Boehme, C. and Frenking, G. Organometallics 1998, 17, Quantum Chemical Calculations for the N-Heterocyclic Carbene Complexes of MCl (M = Cu, Ag, Au)

8 Motivation  Using NHCs ligand to replace phosphine ligand in organomatallic catalysis. organomatallic catalysis.  In comparison with other transition metals (Cu, Au), silver has been virtually untouched as a catalyst for coupling reactions.  To promote silver-catalyzed three-component coupling of aldehyde, alkyne, and amine.  Easy recovered effectivetly recycled Immobilization of NHC-Ag(I) complexs onto Au Nanoparticles. Immobilization of NHC-Ag(I) complexs onto Au Nanoparticles.

9Experimental Preparation of [Ag(hmim) 2 ]PF 6 Complex

10 Space linker synthesisExperimental Preparation of Au NPs-Ag(I)(NHC) 2 (PF 6 )

11Experimental Preparation of Au NPs-Ag(I)(NHC) 2 (PF 6 )

12 1 H NMR Spectra of [Hmim]HPF 6 and [Ag(hmim) 2 ]PF 6 2H

13 c C *DMSO C 13 C NMR Spectra of [Hmim]HPF 6 and [Ag(hmim) 2 ]PF 6

14 ESI-MS Spectrum of [Ag(hmim) 2 ]PF 6 Experimental MS Data Calculated MS Data

15 IR Spectra of [Hmim]HPF 6 and [Ag(hmim) 2 ]PF 6 [Ag(hmim) 2 ]PF 6 a (hmim)HPF 6 b 1225 cm cm -1 NHC H-C-C & H-C-N bending

16 UV Spectra of [Hmim]HPF 6 and [Ag(hmim) 2 ] PF 6 [ Ag(hmim) 2 ]PF 6 a (hmim) 2 PF 6 b b a π π* 210 nm

17 Single-Crystal X-ray Structure of [Ag(hmim) 2 ]PF 6 bond lengths [Å] bond angles [deg] Ag(1)-C(1)2.083(3)C(2)-Ag(1)-C(11) Ag(1)-C(11)2.083(3)N(1)- C(1)-N(2) N(3)- C(11)-N(4) Dihedral Angle o (221) π π interaction

18 31 P NMR 19 F NMR 1 H, 31 P, and 19 F Spextra of Au-NPs- NHC Ligand *DMSO * -SH -CH 2 SH

19 Synthesis of Au NPs-Ag(I)-(NHC) Complex Cross-link network structure

20 1 H 2 H 31 P NMR 19 F NMR 1 H, 31 P, and 19 F ofAu NPs-Ag(I)-NHC Complex 1 H, 31 P, and 19 F of Au NPs-Ag(I)-NHC Complex *DMSO *

21 1 H NMR Spectra of Ligand, Molcular and Au Nanoparticles *DMSO * * *

22 Particle size 2.1 ± 1.12 nm Synthesis of Octanethiol Protected Au-SR NPs

23 Particle size 3.1 ± 1.3 nm TEM Image and UV Spectrum of Au NPs-Immobilized (NHC) Ligand 230 nm Ligand centered π π*

24 TEM Image and EDS of Au NPs-Ag(I) Complex Particle size: 2.1 ± 0.7 nm 245 nm

25 IR Spectra of Ligand & Au Nanoparticles series SH stretching NHC H-C-C & H-C-N bending 1169 cm cm -1

26 Aldehyde, Amine, and Alkyne-coupling Reactions (A 3 -Coupling) 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,

27 The First Silver-Catalyzed Three-Component Coupling of Aldehyde, Alkyne, and Amine Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003, EntryCatalyst (3 mol%)Time (h)Conversion (%) 1AgOTf1440 2AgBF Ag 2 O1440 4Ag 2 SO AgNO AgF1440 7AgBr1455 8AgCl1460 9AgI1475

28 Proposed Mechanism for the Three –Component Coupling Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003, C-H activation

29 Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL EntrySolvent, TemperatureTimeConversion (%) a 1Propionitrile (97 o C)1hr91 2Acetonitril (83 o C)1hr73 3(hmim)Br1hr29 4(hmim)PF 6 1hr78 51,4-dioxane (105 o C)1hr20 6DMF (154 o C)1hr38 Ag(I)-Catalyzed A 3 -Coupling Reactions

30 Ag(I)-Catalyzed A 3 -Coupling Reactions

31 Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL EntryTime (h)Yield a (%) A 3 -Coupling Reactions of Aliphaticaldehyde, Amine, and Alkyne

32 EntryRTime (h)Yield a (%) 1H p-OMe p-Me265 4p-Cl o-Cl A 3 -Coupling Reactions of Aromaticaldehyde, Amine, and Alkyne Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL

33 EntryTime (min)Yield a (%) A 3 -Coupling Reactions of para-Formaldehyde, Amine, and Alkyne Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

34 A 3 -Coupling Reactions of para-Formaldehyde, Amine, and Alkyne EntryTime (min)Yield a (%) Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

35 EntryRTime (h)Yield a (%) A 3 -coupling Reactions of Benzaldehyde, Amine, and Alkyne pKa Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL

36 Convection transition Thermal v.s. Microwave Heating Kappe, C. O. Angew. Chem. Int. Ed. 2004, 43, microwavethermal

37 Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL EntryTime (sec)Yield a (%) A 3 -Coupling Reactions of Aliphaticaldehyde, Amine, and Alkyne

38 EntryTime (sec)Yield a (%) A 3 -coupling Reactions of para-Formaldehyde, Amine, and Alkyne Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

39 A 3 -Coupling Reactions of para-Formaldehyde, Amine, and Alkyne EntryTime (sec)Yield a (%) Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

40 EntryTime (sec)Yield a (%) A 3 -Coupling Reactions of Benzaldehyde, Amine, and Alkyne Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

41 Proposed Mechanism for the A 3 -Coupling Reaction

42 A 3 -Coupling Reactions Catalyzed by a Reusable PS-supported Ag(I)-NHC complex Wang, Li. P.; Zhang, Y. L.; Wang M. Tetrahedron Letters – Structure indefinite 2.Quantitative NHC-Silver (I) by ICP-Mass 24 h

43 Au-[hmim] 2 AgPF 6 : 9 mg 1,2,4,5-tetramethylbenzene : 5 mg d 6 -DMSO 4 H 2 H 0.25 : 0.13 = X : X = mmol – lignad ×0.5 = mmol- metal center /9 = mol/g Quantitative by NMR AA analysis: mol/g ICP-Mass anlysis: mol/g 需時 2 天 送校外 10 min

44 Reaction conditions: Catalyst loading = 20 mol%; para-formaldehyde = 1.00 mmol; pyperidine = 1.10 mmol; phenylacetylene = 1.50 mmol propionitrile = 1.0 mL Recycle No. Time (h)Yield (%) Reusable Au NPs-Ag(I)(NHC) 2 PF 6 Catalyst for A 3 -Coupling Reaction

45 Reactivity Comparision Between Au NPs- Ag(I)(NHC)(PF 6 ) and [Ag(hmim) 2 ]PF 6 Entry Time (min) Cat. 3 Yield (%) Cat. 10 Yield (%) > Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

46Conclusions 1.The air- and water-stable catalyst [Ag(hmim) 2 ]PF 6 was synthesized and characterized by 1 H- and 13 C-NMR, ESI-MS, IR, UV, X-ray. 2.We have developed a methodology to successfully immobilize [Ag(hmim) 2 ]PF 6 onto surfaces of Au NPs. The structure of the supported Ag(I)-NHC complex catalyst was characterized by 1 H-NMR, IR, TEM, UV, EDS, AA, ICP-Mass. 3.Since the Au NPs- Ag(I) hybrid catalysts are highly soluble in organic solvents, their structures and reactions were studied by simple solution NMR technique. 4. We have successfully demonstrated the catalytic activity of the Ag(I) complex for the three-component coupling reactions of aldehyde, alkyne, and amine. 5. The Au NPs- Ag(I) catalyst can be quantitatively recovered and effectively reused for many times without any loss of reactivity.