Abstract: A new room-temperature spin crossover complex [Fe(dpp)(Mepy)2(NCS)2] was prepared. Elemental analysis, infrared spectrum, electrospray ionization mass spectrum and ultraviolet spectrum were used to study the structure of the complex. The temperature dependence of magnetic susceptibility shows that the temperature of spin transition is 330K. By comparing the complex with the other resemble structural complexes, it reveals that the modification of ligand will influence the critical temperature and hysteresis loop of spin crossover greatly.

Key words: magnetic susceptibilities, spin crossover, spin transition, molecule material