Imparting hysteretic behavior to spin transition in neutral mononuclear complexes?

RSC Advances Pub Date: 2016-04-20 DOI: 10.1039/C6RA05342D

Abstract

A series of spin transition neutral compounds [FeL(NCS)2] has been synthesized and characterized by means of magnetic susceptibility studies, X-ray diffraction, IR and M?ssbauer spectroscopic, and calorimetric measurements (L = N,N-bis((3-alkoxypyridin-2-yl)methylene)-propane-1,3-diamine, number of carbon atoms in chains (n) = 4, 12, 14, 16, 18, 20). The shortest chain compound is crystalline and displays a gradual spin transition above ambient temperature. Growing the aliphatic substituent up to n = 12 and 14 leads to loss of crystalline order and deterioration of magnetic properties. At the critical chain length n = 16 and above, the compounds undergo a phase transition reflected by a spin transition and resulting in the appearance of susceptibility hysteresis initially not observed for the short chain congener. For the compound with n = 20, hysteresis becomes the most pronounced. The study shows the importance of chain length optimization for effective feedback between phase and spin transitions.

Graphical abstract: Imparting hysteretic behavior to spin transition in neutral mononuclear complexes
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