Fe(II) spin transition including an amino-ester 1,2,4-triazole derivative, operating at, below and above room temperature

[Fe(αEtGlytrz)3](NO3)2 displays a hysteresis loop of 60 K width, centered at room temperature along with a thermochromic effect. Such bistability domain is the widest for Fe(II) chains with 4R-1,2,4-triazole as ligands. Structure−properties relationships are discussed for this new family of spin-crossover chains with the ethyl-4H-1,2,4-triazol-4-yl-acetate (αEtGlytrz) ligand