Enhanced Circularly Polarized Luminescence by a Homochiral Guest–Host Interaction in Gyroidal MOFs, [Ru(bpy) ₃] [M ₂(ox) ₃] (bpy = 2,2′-Bipyridyl, ox = Oxalate, M = Zn, Mn)

Abstract

We report the circularly polarized luminescence (CPL) for [Ru(bpy) ₃]I ₂ ( 1) and [Ru(bpy) ₃][M ₂(ox) ₃] (M = Zn ( 2), Mn ( 3)). Whereas compound 1 is a simple salt of [Ru(bpy) ₃] ²⁺, 2 and 3 are MOFs in which the chiral [Ru(bpy) ₃] ²⁺ ions are encapsulated in a homochiral gyroidal skeleton of [M ₂(ox) ₃] ^2–. Whereas the solution of 1 exhibited weak CPL with a luminescence dissymmetry factor of | g _lum| ∼ 10 ^–4, the CPL was significantly enhanced in solid-state 1– 3 with | g _lum| = 2 × 10 ^–2 for 1, 4 × 10 ^–2 for 2, and 1 × 10 ^–1 for 3. The enhanced CPL in 3 was attributable to an energy transfer between the homochiral guest and host in 3.