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Title. LCC Petr á Szilagyi, G. Moln á r, A. Bousseksou. Spain ICMol J. A. Real. "Molecules and Materials" group Laboratoire de Chimie de Coordination Toulouse. Spin transitions in Ni(dmit) 2 complexes. Christophe Faulmann. Stéphane Dorbes (Ph-D next november).

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  1. Title LCC Petrá Szilagyi, G. Molnár, A. Bousseksou Spain ICMol J. A. Real "Molecules and Materials" group Laboratoire de Chimie de Coordination Toulouse Spin transitions in Ni(dmit)2 complexes Christophe Faulmann Stéphane Dorbes (Ph-D next november) Chem. Commun, 2005, 69-71 Eur. J. Inorg. Chem., 2005, 3261-3270

  2. Intro Conductive properties Magnetic properties FeIII Spin-Crossover Systems Ni(dmit)2 Complexes (SCO)(anion) + [Ni(dmit)2](NBu4) [Ni(dmit)2](SCO) [Ni(dmit)2](SCO)  [Ni(dmit)2]x(SCO) (electrocrystallization)

  3. Spin transition + eg eg t2g t2g Weak field High spin (HS) S = 5/2 Strong field Low spin (LS) S = 1/2 .K) -1 HS .mol 3 T (cm c LS Temperature Fe(III) complexes (octahedral) Temperature, Pressure, Light... Bond lengths variations (3% to 5%) Spin-Crossover Systems Fe complexes

  4. Transition FeIII [Fe(sal2-trien)]+ with (PF6)- or (BPh4)- PF6 BPh4 Sinn, Wilson et al., J. Am. Chem. Soc., 1978, 3375

  5. ligand et complex Chem. Commun, 2005, 69-71 [Ni(dmit)2](NBu4) + [Fe(sal2-trien)](PF6) CH3CN 4°C [Fe(sal2-trien)][Ni(dmit)2]

  6. SQUID measurements on [Fe(sal2trien)][Ni(dmit)2] hysteresis HS cT values plateau FeIII cT (cm3.mol-1. K) LS T (K) TOTAL T° Mossbauer, DSC, XRD, EPR, IR, Pressure, hn...

  7. Mossbauer coll. A. Bousseksou (Toulouse) 300 K FeIII HS FeIII LS 250 K 230 K 210 K- 80 K 80 K – 250 K -2 -1 0 1 2 3 -1 100 % d = 0.38 mm.sec-1 DEQ = 0.56 mm.sec-1 * * * * * 100 % d = 0.12 mm.sec-1 DEQ = 2.70 mm.sec-1

  8. Mossbauer2 100 % HS 300 K 250 K 250 K 260 K 230 K 290 K 230 K- 80 K 80 K – 250 K 100 % HS 100 % LS

  9. DSC-Volume coll. A. Bousseksou (Toulouse) DV by XRD, DSC: DS ( 25 J/K.mol) DS = DSvib. + DStrans°. IR/EPR : Vibrational aspect of the transition Temperature of Transition vs Pressure (DS/ DV) V (Å3) DSC (mW/mg) 217.6 K exo 10 K/min 217.8 K 5 K/min 15.4 Å3 10 K/min 249.3 K T (K) 250.1 K T (K) Mossbauer HS and LS fraction; Relaxation time (10-7 sec.) LIESST effect ? Problem: how to compare ?

  10. RX295-180 Structure of [Fe(sal2-trien)][Ni(dmit)2] at 295 K layer of Ni(dmit)2 layer of Ni(dmit)2 slab of Fe(sal2-trien)

  11. Structure of [Fe(sal2-trien)][Ni(dmit)2] RX_2 295-180 layer of Ni(dmit)2 layer of Ni(dmit)2 slab of Fe(sal2-trien) 295 K layer of Ni(dmit)2 layer of Ni(dmit)2 180 K slab of Fe(sal2-trien) a = 9.2530(9) Å a= 79.5(1)° b = 11.708(1) Å b= 78.11(1)° c = 17.241(2) Åg = 68.48(1)° V = 1688.6(3) Å3 a = 8.888(1) Å a= 81.612(2)° b = 12.252(1) Å b= 82.19(2)° c = 15.911(2) Åg = 74.322(13)° V = 1641.8(3) Å3

  12. Interactions within [Fe(sal2-trien)][Ni(dmit)2] ribbonFe 295 K 295 K Type 2 180 K 180 K Type 1 180 K 180 K 3.1-3.4 Å 3.3-3.6 Å 3.1-3.4 Å 3.3-3.6 Å

  13. OrientCation Fe-O 1.87 1.90 Fe-Nimine 1.93 2.12 Fe-Namine 157 175 176 Nimine-Fe-Nimine O-Fe-Namine 178 HS LS 2.00 2.19 295 K 180 K Environment of Fe in [Fe(sal2trien)][Ni(dmit)2]

  14. Relative orientation of [Fe(sal2trien)]+ in [Fe(sal2trien)][Ni(dmit)2] at 295 K and 180 K OrientCation and the conductivity ?

  15. RX2 Sal2trienx Electrocrystallization of [Fe(sal2trien)][Ni(dmit)2] needles and plates and powder [Ni(dmit)2]0 and [Fe(sal2trien)][Ni(dmit)2]3 and ? [Fe(sal2trien)][Ni(dmit)2]3 290 and 180 K Bond lengths around Fe:HS fraction

  16. RX1 Sal2trienx S...S contacts between Ni(dmit)2 units in [Fe(sal2trien)][Ni(dmit)2]3 Electrical and Magnetic measurements 290 and 180 K

  17. Cond_Sal2trienx Electrical conductivity of [Fe(sal2trien)][Ni(dmit)2]3 (checked by XRD) s (S/cm) log s 350 K Ea =230 meV 150 K T (K) 1000/T

  18. Magnetic measurements on whole batches obtained by electrocrystallisation (plates, needles and powder) M(T) polyphase 6 10-3 M (emu) 7.4 10-5 4 10-3 7.0 10-5 c 2 10-3 [Ni(dmit)2]0 [Fe(sal2trien)][Ni(dmit)2]3 and ??? 6.6 10-5 310 330 270 290 T / K 0 0 50 100 150 200 250 300 350 T / K [Ni(dmit)2]0 [Fe(sal2trien)][Ni(dmit)2]3 and ??? coll. J. A. Real (Valencia)

  19. Assuming only [Fe(sal2trien)][Ni(dmit)2]3 in the batches obtained by electrocrystallisation Magn_fract. XRD : HS fraction T (K) LS fraction To isolate [Fe(sal2-trien)][Ni(dmit)2]3 and the phase responsible of the hysteresis

  20. Magnetism Magnetic measurements of [Fe(sal2trien)][Ni(dmit)2]3 (eye-selected plates from several electrocrystallisations) coll. J. A. Real (Valencia) Total amount : < 1 mg Paramagnetic sample, without spin transition or hysteresis

  21. Conclusion * 1/1 and fractionnal oxydation state compounds with SCO * 1/1 : full characterization still in progress (X-ray, magnetic measurements, Mossbauer spectroscopy, DSC, IR, effect of pressure, LIESST effect...) * Composition and characterization of the powder

  22. photo equipe The "Molecules and Materials" team http://www.lcc-toulouse.fr/equipes/equipe_b/equipe_b.html

  23. Volume V (Å3) 15.4 Å3 T (K) Mossbauer * HS and LS fraction * Relaxation time (10-7 sec.) *LIESST effect ? DV by XRD Problem: how to compare ?

  24. DSC DSC (mW/mg) coll. A. Bousseksou (Toulouse) 217.6 K exo 10 K/min 217.8 K 5 K/min 5 K/min 10 K/min 249.3 K 250.1 K T (K) DS ( 25 J/K.mol) DS = DSvib. + DStrans°. To do : IR/EPR :Vibrational aspect of the transition Temperature of Transition vs Pressure (DS/ DV)

  25. synt Sal2trien [Fe(sal2-trien)]PF6 MeOH

  26. cycle Faraday measurements on [Fe(sal2-trien)][Ni(dmit)2] cT (cm3.mol-1. K) T (K)

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