A photoluminescent organosuperelastic crystal of 7-amino-4-methylcoumarin

Abstract

A unique mechanical property of superelasticity is observed not only in so-called shape-memory alloys but also in molecular crystals. In contrast, superelasticity can coexist with various attractive functions derived from molecules in the latter. Herein we demonstrate a photoluminescent organosuperelastic crystal of a pure organic compound: 7-amino-4-methylcoumarin. UV light irradiation causes a negligible effect on a stress–strain curve with a typical superelastic hysteresis loop in the crystal. The emission color of yellow-green is visually unchanged during the superelastic deformation because of the twinning nature. Superelasticity coexisting with photoluminescence properties is unprecedented in the conventional SMAs and indicates promising practical applications of molecular crystals as the next generation superelastic materials.