, CH3CN,
CH2Cl2 (11%).
9
11 %](https://image.slidesharecdn.com/juliaponcethesisp1-140702051704-phpapp01/85/Julia-ponce-thesis-Part1-9-320.jpg)
![Synthesis
of
the
thread
Assembly of the building blocks : a) neo2B2, [PdCl2(dppf)ferrocene], DMSO 80 0C (49%); b) Pd(PPh3)4, DMF, K2CO3, H2O
(28%); c) CBr4, 2-‐‑propanol, light (81%); d) NaH, propargyl bromide, THF 45 0C (80%).
11](https://image.slidesharecdn.com/juliaponcethesisp1-140702051704-phpapp01/85/Julia-ponce-thesis-Part1-11-320.jpg)
, CH3CN-‐‑CH2Cl2.
33 %
27](https://image.slidesharecdn.com/juliaponcethesisp1-140702051704-phpapp01/85/Julia-ponce-thesis-Part1-27-320.jpg)
2
*
2.073
2.276
[Cu(dpp)(terpy)](PF6)2
*
2.045
2.233
166
*F. Baumann, A. Livoreil, W. Kaim, J. P. Sauvage Chem. Commun. 1997, 35-‐‑36.
X-‐‑band EPR spectra recorded at 4 K in frozen
acetonitrile solution (a) and in powder (b)
samples. Microwave frecuency of 9.4723 GHz.
Characterization
of
Cu(II)
rotaxanes
EPR
31](https://image.slidesharecdn.com/juliaponcethesisp1-140702051704-phpapp01/85/Julia-ponce-thesis-Part1-31-320.jpg)
Julia ponce thesis Part1
- 1. PhD Thesis Defense Julia Ponce González 13 June 2014 Coordination compounds for molecular electronics: Synthesis, characterization and electronic transport properties of copper rotaxanes and molecular complexes.
- 2. 2 Chapter 1 Copper rotaxanes
- 3. Copper rearrangement Cu (II) Cu (I) Square pyramidal Tetrahedral 2+ + 3
- 4. Copper-‐complexed biestable rotaxanes 4 Rotational motions Pirouetting rotaxanes Shuttling rotaxanes Linear motions
- 5. 5 Shuttling rotaxanes Pirouetting rotaxanes Linear motions Rotational motions Copper-‐complexed biestable rotaxanes
- 6. Limiting step 6 Slow terpy phen
- 7. Shuttling rotaxane 7 Minimum distance between stations 3,8-‐‑Substitution on the thread 'ʹFast redox-‐‑triggered shuQling motions in a copper rotaxane based on a directly bonded phenanthroline/terpyridine conjugate'ʹ Coronado, E.; Gaviña, P.; Ponce, J.; Tatay, S.. Tetrahedron. submi1ed.
- 8. Acceleration of the rearrangement Nucleophilic attack Mixed 2,9 / 3,8 -‐‑substitution 2,9-‐‑Substitution 8
- 9. Synthesis Capping by Click Chemistry Capping of R1+: a) Cu(Me6Tren)Br, Na2CO3, Sodium ascorbate, CH3CN, CH2Cl2.; b) KCN aq.; c) [Cu(CH3CN)4](PF6), CH3CN, CH2Cl2 (11%). 9 11 %
- 10. Synthesis of the thread Synthesis of asymmetrically substituted terpy and phen building blocks: a) Pd(PPh3)4, toluene (65%); b) NBS, dichloromethane, H2O, light (77%); c) Pd(PPh3)4, DMF, K2CO3, H2O (33%). 10 32 % 33 %
- 11. Synthesis of the thread Assembly of the building blocks : a) neo2B2, [PdCl2(dppf)ferrocene], DMSO 80 0C (49%); b) Pd(PPh3)4, DMF, K2CO3, H2O (28%); c) CBr4, 2-‐‑propanol, light (81%); d) NaH, propargyl bromide, THF 45 0C (80%). 11
- 12. 1H NMR 12 1H NMR spectra of axle precursor 2 and rotaxane R1(PF6) recorded in CDCl3 and CD2Cl2 respectively.
- 13. Electrochemical characterization +0.48 V +0.63 V-0.05 V E Cu I/II vs SCE 0.0 V Cyclic voltammogram at 100 m V / s s c a n r a t e i n dichloromethane/ acetonitrile (1:9) using TBA(PF6) 0.1 M as supporting electrolyte. CuN5 CuN4 13
- 21. Cyclic voltammograms in dichloromethane TBA(PF6) 0.1 M of rotaxane R1(PF6) at 50, 100, 400, 600 and 800 scan rate. Working curve reported in R. S. Nicholson, I. Shain Anal. Chem. 1964, 36, 706-‐‑723. Estimation of the kinetic constant V ia ic 21 R1+ k = 0.15 s-‐‑1 t1/2 = 4.6 s
- 22. Kinetic constants k = 0.15·∙10-‐‑3 s-‐‑1 R1+ k = 0.15 s-‐‑1 t1/2 = 4.6 s Collin, J. P.; Durola, F.; Mobian, P.; Sauvage, J. P. Eur. J. Inorg. Chem. 2007, 2420-‐‑2425. Poleschak, I.; Kern, J. M.; Sauvage, J. P. Chem. Commun. 2004, 10, 474-‐‑476. Armaroli, N.; Balzani, V.; Collin, J. P.; Gavina, P.; Sauvage, J. P.; Ventura, B. J. Am. Chem. Soc. 1999, 121, 4397-‐‑4408. k = 1 s-‐‑1 k = 5 s-‐‑1 5-‐fold increase 22
- 23. Pirouetting rotaxane 23 3,8-‐‑Substitution on the thread Pyridine bisamine ‘Fast piroueQing motion in a pyridine bis-‐‑amine-‐‑containing copper-‐‑complexed rotaxane’ E. Coronado, P. Gaviña, J. Ponce and S. Tatay, Chem. Eur. J., 2014, 20, 6939-‐‑6950.
- 24. Pyridine bisamine chelate Synthetically accesible tridentate chelate Compatible with Cu(I) 92 % 24 14 % 57 % 36 %
- 25. Pyridine bisamine chelate High stabilization of the cupric state Terpy Pyridine bisamine 25
- 26. Two rotaxanes Reference monostable rotaxane Bistable rotaxane 26
- 27. Synthesis of R2+ Capping by Click Chemisrty Rotaxane R2+ prepared by the threading followed by capping approach: a) Cu(Me6tren)Br, Na2CO3, sodium ascorbate, CH3CN, CH2Cl2; b) KCN aq; c) [Cu(CH3CN)4](PF6), CH3CN-‐‑CH2Cl2. 33 % 27
- 28. Synthesis of R3+ Capping by Click Chemistry 28
- 29. Synthesis of R3+ Clipping by Imine Covalent Chemistry Rotaxane R3+ prepared in one pot by the clipping approach: a) 2,6-‐‑pyridinedicarbaldehide, MeOH; b) NaBH4 (22 %). 29 22 %
- 30. Characterization of Cu(I) rotaxanes 1H NMR 30
- 31. Rotaxanes oxidation: R(PF6) + NOBF4 →𝐾𝑃𝐹6┴ R(PF6)2 g⊥ g‖ A‖ (G) R2(PF6)2 2.065 2.269 150 R3(PF6)2 2.063 2.225 172 [Cu(dpp)2](PF6)2 * 2.073 2.276 [Cu(dpp)(terpy)](PF6)2 * 2.045 2.233 166 *F. Baumann, A. Livoreil, W. Kaim, J. P. Sauvage Chem. Commun. 1997, 35-‐‑36. X-‐‑band EPR spectra recorded at 4 K in frozen acetonitrile solution (a) and in powder (b) samples. Microwave frecuency of 9.4723 GHz. Characterization of Cu(II) rotaxanes EPR 31
- 32. Electrochemical characterization -0.56 V 1.1 V +0.60 V +0.63 V-0.05 V-0.41 V E Cu I/II vs SCE -0.56 V C y c l i c vo l t a m m o g r a m o f r o t a x a n e R 3 ( P F 6 ) i n dichloromethane TBA(PF6) 0.1 M solution at 0.1 V/s. CuN5 CuN4 CuN6 32
- 33. Estimation of the kinetic constant 𝐸↓𝑎 = 𝐸↓1/2 −( 𝑅 𝑇/ 𝑛𝐹 )(0.780− 𝑙𝑛√ 𝑘/𝑎 ) a= 𝑛𝐹𝑣/ 𝑅𝑇 R3+ k = 620 s-‐‑1 t1/2 = 1.1 ms Cyclic voltammograms in TBA(PF6) 0.1 M dichloromethane buffer solution of rotaxane R3(PF6) at different scan rates (solid lines), and rotaxane R2(PF6) at 0.1 Vs-‐‑1 (dashed line). V Linear fiQing of the potential shift. The rate constant value was extracted from the y-‐‑interception. R. S. Nicholson, I. Shain Anal. Chem. 1964, 36, 706-‐‑723. << k/a 33
- 34. Kinetic constants k = 5 s-‐‑1 ECuN4-‐‑ECuN5 = 0.49 V Poleschak, I.; Kern, J. M.; Sauvage, J. P. Chem. Commun. 2004, 10, 474-‐‑476. 34 R3+ k = 620 s-‐‑1 ECuN4-‐‑ECuN5 = 1.1 V
- 35. Conclusions Synthetic methodologies • Click chemistry does not constitute a feasible approach for the preparation of bistable copper rotaxanes. 35 Approach Methodology Yield R1(PF6) Capping Click Chemistry 11 % R2(PF6) Capping Click Chemistry 33 % R3(PF6) Capping Click Chemistry 0 % R3(PF6) Clipping Imine condensation and reduction 22 %
- 36. Conclusions Synthetic methodologies • The pyridine bisamine results a synthetically accessible tridentate chelate and affords a feasible route for the preparation of piroueQing rotaxanes by a clipping methodology. 36
- 37. Conclusions 37 Electrochemical behaviour • The shuQling motion of copper rotaxanes can be greatly accelerated by the approximation of tetra and penta coordination sites.
- 38. Electrochemical behaviour • The high stabilization of the cuprous and cupric states in R3+, afforded an enhanced redox state separation related to the large switching rates. • The wide redox hysteresis and the fast electrochemical response exhibited by R3+ makes it a very promising candidate for the development of redox-‐‑switching molecular devices. Conclusions 38