NANOPARTICLES OF A SPIN TRANSITION COMPOUND

摘要

The invention relates to a material composed of nanoparticles essentially comprising a spin transition compound. The compound is of the formula [(Fe_1-yM_yL₃)_wL₃][X_2/x(1-z/x')Y_2z/x']_w, in which L represents a 1,2,4-triazole ligand which bears a substituent R on the nitrogen in position 4; X is an anion of valency x, 1 = x = 2; Y is an anion which is other than X and is of valency x', 1 = x' = 2; R is an alkyl group or a group R¹R²N in which R¹ and R² each independently of one another represent H or an alkyl radical; M is a metal having a 3d⁴, 3d⁵, 3d⁶ or 3d⁷ configuration, other than Fe; 0=y=1; 0=z=2; 3=w=1500. Applications: thermochromic pigment, data storage, optical limiters, contrast agent.