Dynamical effects on the magnetic properties of dithiazolyl bistable materials

ジチアゾリル双安定性物質の磁性における動的効果

Vela, S.*; Deumal, M.*; 志賀 基之   ; Novoa, J.*; Ribas-Arino, J.*

Vela, S.*; Deumal, M.*; Shiga, Motoyuki; Novoa, J.*; Ribas-Arino, J.*

これまで、分子磁性体における磁気的性質はX線結晶解析などで得られる一つの分子構造で決まるものと考えられてきた。しかし、第一原理計算に基づく計算化学的手法によりこれを検証したところ、一点の構造における磁性と、露に温度ゆらぎを取り入れた磁性の計算は、必ずしも一致しないことがわかった。特に、結晶中におけるラジカルが大振幅振動を起こすような、静的な描像に限界がある。そのような分子磁性体である1,3,5,トリチア-2,4,6トリアザペンタレニル(TTTA)系を例としてこれを実証する。

The magnetic properties of molecule-based magnets are commonly rationalized by considering only a single nuclear configuration of the system under study, usually X-ray crystal structure. Here, by means of a computational study in which the results obtained using such a static approach and those obtained by explicitly accounting for thermal fluctuations are compared, we uncover that the serious limitations of the static perspective when dealing with magnetic crystals whose radicals undergo wide-amplitude motions. As a proof of concept, these limitations are illustrated for magnetically bistable 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) material. The discovery that a single X-ray structure is not adequate enough to interpret the magnetic properties of TTTA is also expected to be decisive in other organic magnets with dominant exchange interactions propagating through labile networks.