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Ionic liquids (IL), use and specific task as solvent in catalytic reaction

Ionic liquids (IL), use and specific task as solvent in catalytic reaction. Thibaut Gutel Ingénieur ESCOM. Laboratoire C2P2 Equipe. Directeurs de thèse : Catherine SANTINI et Yves CHAUVIN. 12-10-2007. Directeur Jean-Marie Basset. Contents : IL, solvent for catalytic reactions.

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Ionic liquids (IL), use and specific task as solvent in catalytic reaction

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  1. Ionic liquids (IL),use and specific task as solvent in catalytic reaction Thibaut Gutel Ingénieur ESCOM Laboratoire C2P2 Equipe Directeurs de thèse : Catherine SANTINI et Yves CHAUVIN 12-10-2007 Directeur Jean-Marie Basset

  2. Contents : IL, solvent for catalytic reactions INTRODUCTION RESULTS A) Synthesis of IL B) Behaviour of ionic compounds in IL C) Behaviour of unsaturated substrates in IL D) Generation of metal nanoparticles in IL CONCLUSION OUTLOOK

  3. What are ionic liquids (IL) ? Ionic liquids Molten salts Organic Cations C+ Organic/Inorganic Anions A- IL are molten salts but Tmp < 100°C  106possible associations of C+ / A- Wasserschied et al. Ionic liquid in synthesis, 2003, Wiley-VCH

  4. Use of IL as solvent in industry [Ni] BMIMAlCl4 1995 : DifasolTM (IFP-Axens) 1995 : Synthesis of 2,5-dihydrofurane (Eastman Chem Co) 2003 : BASILTM (BASF) synthesis of phosphite C8= C4= Favre et al. Petrol. Tech. 2002, 441, 104-109. Falling et al. In U.S. Pat.; Eastman Kodak Co., USA, 1993; p 8. Maase et al. In PCT Int. Appl.; Basf: Germany, 2003; Vol. 2003062171, p 60

  5. Why are IL interesting in catalysis ?  new opportunity as solvent for catalytic reaction • Low vapor pressure and non-flammable  Safety and ecological considerations • Low melting point and high thermal stability  Process optimization • Non-miscible with alkanes and/or water •  Multiphase catalysis and immobilization of the catalyst • Tunable physico-chemical properties  Adjustment of viscosity, density or acidity Welton et al. Ionic liquid in catalysis, Coord. Chem. Rev, 2004, 248, 2459-2477 Olivier-Bourbigou et al. Multiphase Homogeneous Catalysis, 2005, Wiley-VCH, 413-431

  6. IL used as reaction media • Solvent IL solubilize reactants without modification But IL are difficult to purify… • Presence of halide  decrease activity in Michael addition Handy et al. Tetrahedron Lett., 2003, 44, 8395-8397  increase activity in Heck reaction Gallo et al. Dalton Trans., 2002, 4339–4342 • Presence of water  decomposition of water sensitive complex increase activity of ruthenium catalyst Daguenet et al. Organomet., 2004, 23, 6080-6083

  7. IL used as reaction media • Solvent IL solubilize reactants without modification • Ligand IL act as a ligand for the catalyst • Reactivity of C2-H : In situ formation of N-heterocyclic carbene • Presence of functional group : Coordination on PdNP Magna et al. Organomet., 2003, 22, 4418-4425 Hahn et al. Angew. Chem. Int. Ed., 2006, 45, 1348-1352 Fei et al. Organomet. 2007, 26, 1588-1598

  8. IL used as reaction media • Solvent IL solubilize reactants without modification • Ligand IL act as a ligand for the catalyst • Catalyst IL intervene as (co-)catalyst • Organocatalyst : Diels-Alder cycloaddition • Lewis acid : catalyst in Friedel-Crafts acylation RCOCl + Al2Cl7- RCO+ + 2AlCl4- Welton et al.Coord. Chem. Rev. 2004, 248, 2459-2477 Stark et al.Dalton trans, 1999, 1, 63-66

  9. Goal : Study of IL as solvents for catalytic reactions Ionic liquids Substrate Catalytic system • IL are non-innocent solvents But IL are associations of C+/A- organized in 3D structure

  10. IL, an association of C+/A- organized in 3D structure IL 3D organisation C+A- Ionic catalyst Unsaturated substrates Ionic exchange ? C1+A1- + C2+A2- C1+A2- + C2+A1- Segregation in microdomains Trapping ? -cation Interaction ? Supramolecular matrix ?

  11. Contents : IL, solvents for catalytic reactions • A) Synthesis of IL • Choice of IL • Synthesis of IL • B) Behaviour of ionic compounds in IL • Study of ionic exchange in 23Na NMR • Influence of the catalytic activity • C) Behaviour of unsaturated substrates in IL • Study of aromatics/IL system by NMR • Study of aromatics/IL system by molecular dynamics • D) Generation of metal nanoparticles in IL • Influence of temperature • Influence of stirring • Influence of alkyl chain length at 0°C

  12. A) IL used in this work C+ Alkylmethylimidazolium (R1R2MIM) A- Bis(trifluoromethylsulfonyl)imide (NTf2) • Why ? • Hydrophobic and liquid at room temperature • Planar cation • Non-coordinating anion • Easy to synthesize and to purify

  13. A) Synthesis of imidazolium based IL • 1) Quaternisation of imidazole by halides • R1, R2 et R3 = alkyl • X= Cl or Br • 2) Anion metathesis • R1, R2 et R3 = alkyl • X= Cl, Br, I • MY=LiNTf2, NaOTf, NaPF6, NaBF4 • Good yield (75-80%) • Very high purity (halide < 50ppm and water < 50ppm) Magna, L. Thèse LCOMS, 2002

  14. Contents : IL, solvents for catalytic reactions IL C+A- • A) Synthesis of IL • Choice of IL • Synthesis of IL • B) Behaviour of ionic compounds in IL • Study of ionic exchange in 23Na NMR • Influence of the catalytic activity • C) Behaviour of unsaturated substrates in IL • Study of aromatics/IL system by NMR • Study of aromatics/IL system by molecular dynamics • D) Generation of metal nanoparticles in IL • Influence of temperature • Influence of stirring • Influence of alkyl chain length at 0°C Ionic catalyst Ionic exchange ?

  15. B) Dissolution of catalytic system in IL • Catalytic activity depends on the nature of IL with TPPMSNa • Catalyst dissolves in IL • 3 BMIMBF4 + K3Co(CN)5  (BMIM)3Co(CN)5 + 3 KBF4 • Suarez et al. Inorg. Chim. Acta, 1997, 207-209 • Parshall et al.J. Am. Chem. Soc., 1972, 94, 8716-8719 Vallée et al.J. Mol. Cat. A, 2004, 214, 71-81

  16. B) Solvation of sodium salt in IL • Question : Na+A1- + C+A2- ??? • A1-: TPPMS-, AcO- • C+ : EMIM+, BMIM+, BMMIM+, Et4N+, Et4P+ • A2- : Cl-, Br-, OTf-, BF4-, PF6-, NTf2- • Techniques : Study in 23Na NMR at solid state • Parameters : 1) Influence of temperature • 2) Presence of water

  17. B) Exchange reaction monitored by 23Na NMR TPPMS-Na+ + BMMIM+PF6- 100°C TPPMS-Na+ + BMMIM+PF6- 120°C TPPMS-Na+ Na+PF6 - Na+Cl- (ref) 60 60 60 60 40 40 40 40 20 20 20 20 0 0 0 0 - - - - 20 20 20 20 - - - - 40 40 40 40 - - - - 60 60 60 60 - - - - 80 80 80 80 ( ( ( ( ppm ppm ppm ppm ) ) ) ) TPPMS-Na+ + BMMIM+PF6-TPPMS-BMMIM+ + Na+PF6- TPPMS-Na+ TPPMS-Na+ IL D d= -17ppm d= -27ppm d=0ppm

  18. B) Conclusion on ionic exchange Na+A1- + C+A2-C+A1- + Na+A- 1) Exchange reaction is governed by the nature of anion A2- = Cl- ; Br- ; OTf-  total exchange C+/Na+ A2- = PF6- ; BF4- partial exchange C+/Na+ A2- = NTf2-  no exchange C+/Na+  The exchange reaction can be predicted by the Hard and Soft Acid Base theory 2) In the case of partial exchange, this reaction is temperature dependent  higher temperature increases the rate of exchange 3) This ionic exchange is water independent  addition of water doesn’t increase the ratio of exchange

  19. B) Explanation of the catalytic activity Vallée et al. J. Mol. Cat. A, 2004, 214, 71-81 • Catalytic activity depends on the nature of IL • A- = Cl- ; Br- ; OTf- total exchange BMMIM+/Na+  low conversion • A- = PF6- ; BF4- partial exchange BMMIM+/Na+  no recycling • A- = NTf2- no exchange BMMIM+/Na+  high conversion • Mobility of phosphine ligand is reduced after exchange • NiL4 NiL3 + L with L : TPPMS-BMMIM+ << TPPMS-Na+ DOSY measurements : D=6.91x10-12m2.s-1 D=10x10-12m2.s-1

  20. Contents : IL, solvents for catalytic reactions IL C+A- 3D Organized • A) Synthesis of IL • Choice of IL • Synthesis of IL • B) Behaviour of ionic compounds in IL • Study of ionic exchange in 23Na NMR • Influence of the catalytic activity • C) Behaviour of unsaturated substrates in IL • Study of aromatics/IL system by NMR • Study of aromatics/IL system by molecular dynamics • D) Generation of metal nanoparticles in IL • Influence of temperature • Influence of stirring • Influence of alkyl chain length at 0°C -cation Interaction

  21. C) IL, a highy organized network of C+ / A- • A rigid network of H-bonded anions and cations • Holbrey et al. Dalton Trans., 2004, 226-2271 • 3D-Organization still presents at liquid state • Billard et al. Inorg. Chem. 2003, 42, 1726-1733 • Dibrov et al. Acta Cryst., 2006, C62, o19±o21

  22. C) Behaviour of aromatics in IL • Molecular dynamics of MMIMPF6 • Formation of liquid clathrates of Benzene/MMIMPF6 Harper et al. Mol. Phys. 2004, 102, 85-94 Holbrey et al. Chem. Com., 2003, 476-477 Hadracre et al. J. Chem. Phys., 2003, 118,273-278 Deetlefs et al.. J. Phys. Chem. 2005, 109, 1593-1598

  23. C) -cation interaction in chemistry • -cation interaction plays a crucial role in biochemistry •  Binding energy of 10 to 30 kcal.mol-1 • -cation interaction in chemistry Ma et al. Chem. Rev., 1997, 97, 1303-1324 Hunter et al. PNAS, 2002, 99, 4873-4876 Yamada et al. Tetrahedron Lett., 2004, 45, 7475-7478 Yamada et al. J. Am. Chem. Soc, 2004, 126, 9862-9872

  24. C) Solvation of unsaturated substrates/IL system • Question : Behaviour of unsaturated substrates in IL • TolueneIL : BMIMNTf2 and BMMIMNTf2 • Techniques : 1) 1H NMR, ROESY and DOSY • 2) Molecular dynamics • in collaboration with Dr Padua • Parameter : Influence of molar ratio (R) of toluene • R= moles of toluene for one mole of IL

  25. C) Evolution of 1H chemical shifts CD2Cl2 IL+ R To

  26. C) Evolution of 1H chemical shifts R=3 R=3 HMe 3 9 2 Har 6 7 8 R=2 R=2 4,5 HMe 3 9 Har R=1 R=1 4,5 6 2 7 8 9 3 2 R=0.5 R=0.5 HMe Har 4,5 6 7 8 R=0.1 R=0.1 3 9 HMe 2 6 Har 7 8 4,5 2 6 BMMIMNTf BMMIMNTf 9 2 3 2 6 4,5 7 8 HMe Har 10 10 10 8 8 8 6 6 6 4 4 4 2 2 2 [ [ [ [ [ [ ppm ppm ppm ppm ppm ppm ] ] ] ] ] ] 3 9 7 8 4,5

  27. C) Study of To/BMMIMNTf2 by ROESY NMR Selective Selective irradiation i rradiation I measured To - IL r ? To - IL C C H H 3 3 M M e e M M e e N N N N H H H H  Study of intermolecular interaction MeTo CH2 HIm CH3 HAr CH2 CH2 CH3 Ämmälahti et al. Magn. Reson, 1996,122, 230-232

  28. C) ROESY experiments M M e e M M e e B B u u N N N N H H H H 2,3 < r < 3,6Å ref Selective Selective I known ref irradiation irradiation Benzene/DMIMPF6 3.5Å  Evaluation of intermolecular distances Chipot et al. J. Am. Chem. Soc., 1996, 118, 2998-3005 Deetlefs et al. J. Phys. Chem. B, 2005, 109, 1593-1598

  29. C) Molecular dynamics and radial distribution • Estimation of intermolecular distances (Pr Padua)

  30. C) To/BMIMNTf2 vs To/BMMIMNTf2 • Evolution of 1H NMR at R = 0.1 to 1 • To/BMIMNTf2 No evolution • To/BMMIMNTf2 Linear shift • ROESY experiments • To/BMIMNTf2 No interaction detected • To/BMMIMNTf2 Strong interaction at R=0.5 and 1 • DOSY results • To/BMIMNTf2 Fast diffusion of toluene • To/BMMIMNTf2 Slow diffusion of toluene • Molecular dynamics • To/BMIMNTf2 Toluene close to alkyl chain • To/BMMIMNTf2 Toluene close to imidazolium ring

  31. C) Conclusion on interaction To/IL

  32. Contents : IL, solvent for catalytic reactions IL 3D organisation Segregation in microdomains Supramolecular matrix ? • A) Synthesis of IL • Choice of IL • Synthesis of IL • B) Behaviour of ionic compounds in IL • Study of ionic exchange in 23Na NMR • Influence of the catalytic activity • C) Behaviour of unsaturated substrates in IL • Study of aromatics/IL system by NMR • Study of aromatics/IL system by molecular dynamics • D) Generation of metal nanoparticles in IL • Influence of temperature • Influence of stirring • Influence of alkyl chain length at 0°C

  33. D) Interest of metal nanoparticles (MNP) • Nanoclusters present unique properties between the bulk and the molecular species • Successful control of the size of MNP using rigid materials such as polymers or dendrimers • Astruc et al. Angew. Chem. Int. Ed., 2005, 7852 – 7872 • Philippot et al. C.R Chimie, 2003, 1019–1034 • IL are good media for the stabilization of MNP • Silveira et al. Chem. Eur. J. 2004, 10, 3734-3740 • But no predictive synthesis of resulting size of MNP

  34. D) IL generates microphase segregation • Molecular dynamics of RMIMPF6 (R=CnH2n+1MIMPF6) • EMIMPF6 (n=2)BMIMPF6 (n=4) HMIMPF6 (n=6) OMIMPF6 (n=8) • X-Ray Diffraction of RMIMCl Canongia Lopes et al.J. Phys. Chem, 2006, 110, 3330-3335 Triolo et al.J. Phys. Chem, 2007, 110, 4641-4644

  35. D) Solvation of polar and nonpolar substrates in IL Nonpolar substrates in nonpolar domains of IL Polar substrates in polar domains of IL Hexane BMIMPF6 in BMIMPF6 Molecular Dynamics and calorimetry Canongia Lopes et al.J.Phys. Chem, 2006, 110, 16816-16818 OMIMNO3 H20 (20% mole) H20 (50% mole) H20 (80% mole) Jiang et al. J. Phys. Chem., 2007, 111, 4812-4818

  36. D) Crystal Growth of RuNP in IL • Hypothesis : Ru(COD)(COT) is nonpolar • 1) preferentially dissolved in nonpolar domains • 2) local concentration increases when n increases

  37. D) Crystal Growth of RuNP in IL • Hypothesis : Ru(COD)(COT) is nonpolar • Question : Control of RuNP size by microphase segregation ? • Study : Crystal growth of RuNP in various IL • Parameters : 1) Influence of temperature • 2) Influence of stirring • 3) Influence of the alkyl chain length

  38. D) Synthesis of RuNP in BMIMNTf2 (n=4) 2.4  0.4nm Gutel et al. J. Mat. Chem., 2007, 17, 3290-3292

  39. D) Synthesis of RuNP in BMIMNTf2 (n=4) + COA 12nm • BMIMNTf2 + COA  swelling of nonpolar domains • Synthesis of RuNP in BMIMNTf2 / COA RuNP : 7 nm Instead of 2.4 nm Ru(COD)(COT) dissolves preferentially in nonpolar domains

  40. D) Influence of temperature in BMIMNTf2 (n=4) 0°C 0.9+/-0.4nm 25°C 2.4+/-0.3nm Temperature decreases  RuNP size decreases Gutel et al. J. Mat. Chem., 2007, 17, 3290-3292

  41. D) Influence of stirring in BMIMNTf2 (n=4) unstirred 0.9+/-0.4nm Stirred 1.1+/-0.2nm Presence of stirring  RuNP size similar  RuNP agglomerated Gutel et al. J. Mat. Chem., 2007, 17, 3290-3292

  42. D) Conclusion of RuNP in BMIMNTf2 • The crystal growth takes place in nonpolar domains of IL • The control of RuNP size is more efficient • when 3D organization is more maintained • Influence of the alkyl chain length at 0°C and in absence of stirring

  43. D) Influence of alkyl chain length at 0°C, unstirred OMIMNTf2 n=8 2.30.8nm EMIMNTf2 (n=2) 2.30.6nm BMIMNTf2 n=4 1.10.2nm DMIMNTf2 n=10 Aggregation HMIMNTf2 n=6 1.90.6nm Gutel et al. Angew. Chem. Int. Ed., Submitted

  44. D) Influence of alkyl chain length at 0°C Gutel et al. Angew. Chem. Int. Ed., Submitted

  45. D) Influence of alkyl chain length at 0°C Linear crystal growth in nonpolar domains Interconnection of nonpolar domains N=586 Polar medium N=201 N=38

  46. D) The crystal growth in IL

  47. CONCLUSION : IL, a non-innocent solvent IL C+A- Ionic catalyst Ionic exchange Na+A1- + C+A2-C+A1- + Na+A- 1) Ionic exchange is governed by the nature of anionand can be predicted by the Hard and Soft Acid Base theory 2) Ionic exchange modify the nature of the catalytic system and consequently the reactivity (isomerization of 2M3BN)

  48. CONCLUSION : IL, a non-innocent solvent IL 3D organisation C+A- Unsaturated substrates -cation Interaction

  49. CONCLUSION : IL, a non-innocent solvent IL 3D organisation C+A- Segregation in microdomains Supramolecular matrix

  50. Outlook • -cation interaction could be used for : • 1) Separation of aromatics / alkanes 2) Stereoselective synthesis • IL could be used as a matrix for nanomaterials : 1) Generalization for other metal nanoparticles 2) Design of IL • ANR CALIST Collaboration C2P2/LCC/LTSP/LECA • PhD student (Paul Campbell)

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