Chiral Electroactive Precursors and Materials

Transcription

1 Chiral Electroactive Precursors and Materials arcis Avarvari MLTECH-Anjou, Université d Angers, C, FACE Conferinta Diaspora tiintifica, Bucuresti, eptembrie 2010

2 Current research topics in the group 1. Chirality in tetrathiafulvalenes (TTF) 2. Electroactive ctiv ligands: TTF-pyridines, -phosphines, s -oxazolines - multifunctional materials - enantioselective catalysis D. Lorcy,. Bellec, M. Fourmigué,. Avarvari, Coord. Chem. ev. 2009, 253, Covalent donor-acceptor compounds: TTF-triazines Me Me 4. Intramolecular mixed valence species X X X = PPh, ime 2, GeMe 2 X = P=, P=, P[M] Me Chem. Eur. J. 2009, 15, 380. Chem. Commun. 2004, Chem. Eur. J. 2007, 13, rganometallics 2009, 28, Functional phosphonate ligands ew J. Chem. 2010, DI : /C0J00204F

3 Tetrathiafulvalene (TTF) and Derivatives -e - -e - + +e e - E 1 2 1/21 = 0,33 V E 1/22 = 0,71 V Electrocrystallization Chemical oxidation salts and charge transfer compounds with conducting and/or magnetic propertiesdetermined by the solid state organization Pt electrode HM TTF and M TTF + crystallization in the presence of anions organic-inorganic segregation mixed valence

4 Tetrathiafulvalene (TTF) and Derivatives Chemical oxidation TTF-TCQ, an organic metal TTF, E ox = 0.33 V + C C C C TCQ, E red = 0.17 V TTF -TCQ incommensurate charge transfer degree J. Ferraris, D.. Cowan, V. Walatka, Jr., J. H. Perlstein, J. Am. Chem. oc. 1973, 95, 948.

5 Tetrathiafulvalene (TTF) and Derivatives Electrocrystallization (TM-TF) 2 X (X = PF 6-, Cl 4-, e 4- ) :a series of superconducting salts C H Cl e b c b c a tacking in (TM-TF) 2 Cl 4 View along a of (TM-TF) 2 Cl 4 D. Jérome, A. Mazaud, M. ibault, K. Bechgaard, J. Phys. Lett. 1980, 41, L195. K. Bechgaard et al., J. Am. Chem. oc. 1981, 103, 2440.

6 Tetrathiafulvalene (TTF) and Derivatives Current trends in TTF chemistry Multifunctional Materials Coexistence or interplay of two or more physical properties within the same material - magnetic anions in mixed-valence TTF-based salts Magnetic conductors BEDT-TTF M 3 _ M = Fe(III), Cr(III) metal-oxalates chiral conductors? And Fe(III), Cr(III), Mn(II), Cu(II), etc. based anions M. Kurmoo, P. Day et al. J. Am. Chem. oc., 1995, 117, E. Coronado, C. J. Gómez-García et al. ature 2000, 408, 447. E. Coronado, P. Day Chem. ev. 2004, 104, Also chiral magnets: magneto-chiral dichroism C. Train,. Gheorghe, V. Krstic, L.-M. Chamoreau,.. vanesyan, G. L. J. A. ikken, M. Gruselle, M. Verdaguer ature Mater. 2008, 7, 729.

7 I. ynthetic challenge Chiral tetrathiafulvalenes - Interests II. Chiroptical redox switches, s chiral recognition n III. Chiral redox active ligands for enantioselective catalysis The control of the metal complexes reactivity upon oxidation - reduction Influence on the catalytic processes? substitutionally inert redox-switchable ligands redox-switchable hemilabile ligands C. A. Mirkin et al. Angew. Chem. Int. Ed. Engl. 1998, 37, 894 IV. Chiral molecular conductors

8 Chiral molecular conductors 1. ptical activity + Electrical conductivity Multifunctional materials 2. Enantiopure forms are inherently less disordered in the crystalline state TTF-X EDT-TTF-Me-oxazoline racemic, and Influence on the conducting properties CH 3 C. éthoré, M. Fourmigué,. Avarvari Chem. Commun. 2004, C. éthoré,. Avarvari, E. Canadell, P. Auban-enzier, M. Fourmigué J. Am. Chem. oc. 2005, 127, A. M. Madalan, C. éthoré, M. Fourmigué, E. Canadell, E. B. Lopes, M. Almeida, P. Auban-enzier,. Avarvari Chem. Eur. J. 2010, 16, eports by ikken et al. on electrical magneto-chiral anisotropy (emcha) effects Chiral WT Krstić, ikken et al. J. Chem. Phys. 2002, 117, Electrical resistance D/L (I,B) = 0 {1 + B 2 + D/L I B} (H, I) # (H, -I) D = - L handedness of the chiral conductor emcha effect (very weak) 4. uperconductivity in non-centrosymmetric systems. oy, C. Kallin, Phys. ev. B 2008, 77, need of a library of chiral precursors in which the chiral information is addressed in different ways everal strategies are envisaged

9 C 2 symmetric chiral tetrathiafulvalenes I. TTF-bis(oxazolines) TTF-BX Cl 2, THF ah, EtH 60 C paramagnetic [M] centers coordination [M] chemistry Lewis acid centers (catalysis) 2 eq C 2 Me ; ah cat * H * H 2 H H H neat, 70 C, 1 day C H 2 Me * H H * * * Cl Cl on-planar conformations * F. iobé,. Avarvari, Chem. Commun. 2009, 3753.

10 I. Complexation * TTF-BX * * (C 5 H 11 ) 2 M(C) 4 M = W,Mo CH 2 Cl 2, 12 h 50 C M(C) 4 * dihedral angles: 47,5 46,5 [BX ()Me]Mo(C) 4 F. iobé,. Avarvari, Chem. Commun. 2009, 3753.

11 C 3 symmetric tetrathiafulvalenes II. Using a C 3 symmetric platform H helical chirality H H H H propeller like conformation H - stacking hydrogen bonds = A.. A. Palmans, J. A. J. M. Vekemans, E. E. Havinga, E. W. Meijer Angew. Chem. Int. Ed. Engl. 1997, 36, 2648 L. Brunsveld, H. Zhang, M. Glasbeek, J. A. J. M. Vekemans, E. W. Meijer J. Am. Chem. oc. 2000, 122, J. van Gestel, A.. A. Palmans, B. Titulaer, J. A. J. M. Vekemans, E. W. Meijer J. Am. Chem. oc. 2005, 127, 5490.

12 C 3 symmetric TTFs: conducting supramolecular wires Electroactive organogel xerogel TEM H H H H H = Et H Thick fibers 100 nm wide and 1-5 m long gel in o-c 6 H 4 Cl 2 7 mg/ml M Thin hn fibers nm wide and nm long I. Danila, F. iobé, J. Puigmarti, A. Pérez del Pino, J. D. Wallis, D. Amabilino,. Avarvari, J. Mater. Chem. 2009, 19, 4495.

13 Doping with iodine T % 60 Dop 120 min 50 Dop 40 min Dop 30 min 40 Dop 20 min Dop 10 min Fresh Doped 30 Undop Xerogel T % Doped after 120 min Doped after 40 min Doped after 30 min Doped after 20 min Doped after 10 min Fresh Doped Undoped Xerogel cm -1 ) cm -1 ) Content in atomic % I After doping 83,11 17,28 6 days later 90,49 9,52 EM/EDX measurements => atio TTF/I 3 2,4/1 -

14 Doping with iodine µm µm na Current (na) Bright zones Dark zones -6 Conducting AFM Voltage (V) uperposed current and topographic measurements I. Danila, F. iobé, J. Puigmarti, A. Pérez del Pino, J. D. Wallis,D. Amabilino,. Avarvari, J. Mater. Chem. 2009, 19, 4495.

15 CCLUI and PEPECTIVE 1. Chiral TTF-oxazolines (TTF-X), bis(oxazolines) (TTF-BX) and bis(bx) - chiral conducting radical cation salts upon oxidation - coordination chemistry: paramagnetic centers multifunctional materials Lewis acidic centers homogenous catalysis - tuning the chiroptical properties upon oxidation and protonation 2. C 3 -symmetry and supramolecular chirality - electroactive organogel and conducting nanofibers - formation of homochiral helical fibers - induction of chirality: sergeants-and-soldiers and soldiers and majority rules

16 Dr. François iobé Ion Danila Acknowledgements Dr. Flavia Piron Dr. Thomas Cauchy Thomas Biet Dr. Diana Branzea Collaborations Dr. D. Amabilino ICMAB, Barcelona, pain AFM, EM, TEM, supramol. chirality Dr. M. Linares Dr. D. Beljonne Univ. of Mons, Belgium Molecular dynamics, CD calculations

17 City of Angers