| abstract |
The invention relates to a material composed of nanoparticles essentially comprising a spin transition compound. The compound corresponds to the formula n n n n n n n [ n n n n ( n n n Fe n n 1 n - n y n n n n n M n y n n n n L n 3 n n n ) n n w n n n n L n 3 n n n ] n n [ n n n X n n n 2 n x n n n n ( n n 1 n - n n z n n x n ′ n n n n ) n n n n n n Y n n n 2 n n n n n n z n n n x n ′ n n n n n ] n n w n n n n n in which L represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; X is an anion having the valency x, 1≦x≦2; Y is an anion other than X having the valency x′, 1≦x′≦2; R is an alkyl group or an R 1 R 2 N— group in which R 1 and R 2 represent, each independently of the other, H or an alkyl radical; M is a metal having a 3d 4 , 3d 5 , 3d 6 or 3d 7 configuration, other than Fe; 0≦y≦1; 0≦z≦2; 3≦w≦1500. Applications: thermochromic pigment, data storage, optical limiters, contrast agent. |