Interplay of antiferromagnetic coupling and spin crossover in dinuclear iron(II) complexes

This article reports on the study of the interplay between magnetic coupling and spin transition in 2,2'-bipyrimidine (bpym)-bridged iron(II) dinuclear compounds. Coexistence of both phenomena has been observed in [Fe(bpym)(NCS)(2)](2)bpym, [Fe(bpym)(NCSe)(2)](2)bpym and [Fe(bt)(NCS)(2)](2)bpym (bpym = 2,2'-bipyrimidine, bt = 2,2'-bithiazoline) by the action of external physical factors namely pressure or electromagnetic radiation. Competition between magnetic exchange and spin crossover has been studied in [Fe(bpym)(NCS)(2)](2)bpym at 6.3 kbar. LIESST experiments carried out in [Fe(bpym)(NCSe)(2)](2)bpym and [Fe(bt)(NCS)(2)](2)bpym at 4.2 K have shown that is possible to achieve dinuclear molecules with different spin states in this class of compounds.