Thermal- and light-induced spin crossover in a guest-dependent dinuclear iron(II) system
Idioma
en
Article de revue
Este ítem está publicado en
Chemistry - A European Journal. 2010, vol. 16, n° 6, p. 1973-1982
Wiley-VCH Verlag
Resumen en inglés
We previously reported the dinuclear material [Fe(II) (2)(ddpp)(2)(NCS)(4)] x 4 CH(2)Cl(2) (1 x 4 CH(2)Cl(2); ddpp = 2,5-di(2',2''-dipyridylamino)pyridine) and its partially desolvated analogue (1 x CH(2)Cl(2)), which ...Leer más >
We previously reported the dinuclear material [Fe(II) (2)(ddpp)(2)(NCS)(4)] x 4 CH(2)Cl(2) (1 x 4 CH(2)Cl(2); ddpp = 2,5-di(2',2''-dipyridylamino)pyridine) and its partially desolvated analogue (1 x CH(2)Cl(2)), which undergo two- and one-step spin-crossover (SCO) transitions, respectively. Here, we manipulate the type and degree of solvation in this system and find that either a one- or two-step spin transition can be specifically targeted. The chloroform clathrate 1 x 4 CHCl(3) undergoes a relatively abrupt one-step SCO, in which the two equivalent Fe(II) sites within the dinuclear molecule crossover simultaneously. Partial desolvation of 1 x 4 CHCl(3) to form 1 x 3 CHCl(3) and 1 x CHCl(3) occurs through single-crystal-to-single-crystal processes (monoclinic C2/c to P2(1)/n to P2(1)/n) in which the two equivalent Fe(II) sites become inequivalent sites within the dinuclear molecule of each phase. Both 1 x 3 CHCl(3) and 1 x CHCl(3) undergo one-step spin transitions, with the former having a significantly higher SCO temperature than 1 x 4 CHCl(3) and the latter, and each has a broader SCO transition than 1 x 4 CHCl(3), attributable to the overlap of two SCO steps in each case. Further magnetic manipulation can be carried out on these materials through reversibly resolvating the partially desolvated material with chloroform to produce the original one-step SCO, or with dichloromethane to produce a two-step SCO reminiscent of that seen for 1 x 4 CH(2)Cl(2). Furthermore, we investigate the light-induced excited spin state trapping (LIESST) effect on 1 x 4 CH(2)Cl(2) and 1 x CH(2)Cl(2) and observe partial LIESST activity for the former and no activity for the latter.< Leer menos
Palabras clave en inglés
Clathrates
Host–guest systems
Iron
Magnetic properties
Spin crossover
Orígen
Importado de HalCentros de investigación