0000000000073843
AUTHOR
Stéphane Dorbes
Towards Molecular Conductors with a Spin‐Crossover Phenomenon:Crystal Structures, Magnetic Properties and Mössbauer Spectra of[Fe(salten)Mepepy][M(dmit) 2 ] Complexes
Three new iron(III) compounds of formula [Fe(salten)Mepepy][M(dmit)2]·CH3CN (M = Ni, Pd, Pt; H2salten = 4-azaheptamethylene-1,7-bis(salicylideneiminate); Mepepy = 1-(pyridin-4-yl)-2-(N-methylpyrrol-2-yl) ethane; dmit2– = 1,3-dithiole-2-thione-4,5-dithiolato) have been synthesised and the crystal structure of each compound has been solved at different temperatures. The structures consist of alternating layers of [M(dmit)2]– units and [Fe(salten)Mepepy] cations. In the Ni compound photo-isomerisation of the Mepepy ligand can be observed in dichloromethane solution. The temperature dependence of the magnetic susceptibility of the compounds reveals a gradual S = 5/2 blabla S = 1/2 spin crossove…
Ferromagnetism in [Mn(Cp*) 2 ] + ‐Derived Complexes: the “Miraculous” Stacking in [Mn(Cp*) 2 ][Ni(dmit) 2 ]
The synthesis and characterisation (X-ray structure and magnetism) of metal complexes (Ni, Au) with the [Mn(Cp*)2]+ cation and the dmit2− and dmid2− ligands are reported. [Mn(Cp*)2][Ni(dmit)2] (1) and [Mn(Cp*)2][Au(dmit)2] (2) exhibit the same structural arrangement, built on stacks of [Ni(dmit)2]− pairs separated by two [Mn(Cp*)2]+ cations, showing a ···D+D+A−A−D+D+A−A−··· motif. On the contrary, the dmid2− derivative [Mn(Cp*)2][Ni(dmid)2]·CH3CN (3) exhibits a totally different structure, built on mixed layers composed of one [Ni(dmid)2]− unit separated by two [Mn(Cp*)2]+ cations, showing a ···D+D+A−D+D+A−···motif. The layers are separated from each other by perpendicular [Ni(dmid)2]− unit…
Temperature and pressure effects on the spin state of ferric ions in the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex
Abstract Thermal and pressure effects have been investigated on the [Fe(sal 2 -trien)][Ni(dmit) 2 ] spin crossover complex by means of Mossbauer spectroscopic, calorimetric, X-ray diffraction and magnetic susceptibility measurements. The complex displays a complete thermal spin transition between the S = 5 2 and S = 1 2 spin states of Fe III near 245 K with a hysteresis loop of ca. 30 K. This transition is characterised by a change of the enthalpy, Δ H HL =7 kJ/mol, entropy, Δ S HL =29 J/Kmol, and the unit cell volume, Δ V HL =15.4 A 3 . Under hydrostatic pressures up to 5.7 kbar the thermal transition shifts to higher temperatures by ca. 16 K/kbar. Interestingly, at a low applied pressure …
Crystal structure, magnetic properties and Mössbauer studies of [Fe(qsal)2][Ni(dmit)2]
Abstract A new compound of formula [Fe(qsal)2][Ni(dmit)2] (1) has been synthesised, structurally and magnetically characterised (qsalH = N-(8-quinolyl)salicylaldimine, dmit2− = 1,3-dithiol-2-thione-4,5-dithiolato). Its structural features and its magnetic behaviour were compared with those of [Fe(qsal)2]-based complexes, and more particularly [Fe(qsal)2][Ni(dmit)2] · 2CH3CN.
[Fe(sal2-trien)][Ni(dmit)2]: towards switchable spin crossover molecular conductors
A cooperative spin transition behaviour with a wide hysteresis loop (30 K) around 240 K has been observed, for the first time, in a salt based on the redox active [Ni(dmit)2]¯, anion and the [Fe(sal2-trien)]+ spin crossover cation. Real Cabezos, Jose Antonio, Jose.A.Real@uv.es