We report a triazole-based trinuclear complex as the first example that displays a complete one-step first-order [HS-HS-HS] ↔ [LS-LS-LS] spin transition at 318 K. The strong ferro-elastic interactions, between the three metal centers, have been identified as the source of the concerted spin transition in this trinuclear complex.

Multifunctional mononuclear iron(ii) complex coordinated with six phosphorescent ligands exhibiting correlated spin-crossover transition and enhanced fluorescence.

We report here the first single crystal investigations, in both high spin (HS) and low spin (LS) states, correlated to magnetic and heat capacity measurements, of a new cooperative and robust spin transition triazole-based Fe II 1-D coordination polymer [Fe(bntrz)3][Pt(CN)4].H2O (1) (bntrz = 4-(Benzyl)-1,2,4-triazole). The compound exhibits a sharp transition at 240 K, accompanied with an anisotropic deformation of the unit cell and a significant gliding of the chains from each other. These two features are identified as the key parameters of the non-conventional mechanical resilience of this system.