An Enantiopair of Organic Ferromagnet Crystals Based on Helical Molecular Packing of Achiral Organic Radicals

作者：Shiomi Daisuke^*; Kanzaki Yuld; Okada Sho; Arima Ryosuke; Miyazaki Yuji; Inaba Akira; Tanaka Rika; Sato Kazunobu; Takui Takeji

来源：Journal of Physical Chemistry Letters, 2011, 2(24): 3036-3039.

DOI：10.1021/jz2014105

We report the ferromagnetic ordering phenomena occurring in organic molecular crystals with structural chirality. Achiral radical 1 has been found to crystallize in two enantiomorphs with chiral space groups of P4(3) and P4(1). The P4(3) form (1L) has left-handed stacking of the molecules, giving the helical chirality in a crystalline solid. In the other form of P4(1) (1R), the right-handed stacking corresponds to a mirror image of IL. Magnetic susceptibility measurements show that both the crystals undergo a ferromagnetic phase transition at T(C) = 1.1 K. The ferromagnetic ordering has been confirmed by heat capacity measurements. The magnetic heat capacity exhibits lambda-shaped peak at T(C) = 1.1 K with an entropy change of R ln 2, as expected for S = 1/2 spins. This is the first example of genuinely organic molecule-based ferromagnetism associated with the structural chirality based on the helical molecular packing in the crystalline solid.

• 出版日期2011-12-15