Pillar-Layer Chiral MOFs as a Crystalline Platform for Circularly Polarized Luminescence and Single-Phase White-Light Emission

The
construction of circularly polarized luminescence (CPL) materials
with high porosity and high rigidity is still challenging. Herein,
we propose a chiral reticular chemistry strategy to prepare the homochiral
porous metal–organic frameworks (MOFs) as CPL-active materials.
Two pairs of enantiomeric MOFs are synthesized through the self-assembly
of chiral D/L-cam (DL-camphorates) and achiral fluorescent ligand
TPB (1,2,4,5-tetra­(pyridin-4-yl)­benzene). The glum values of Cd-CMOF-D and Cd-CMOF-L were up to 0.010 and
0.009; the high glum values could be compared
to those of the partially pure multicomponent self-assembly systems
obtained by the complicated process. We further trace the generation
and transfer of the hierarchical chirality from chiral molecule to
3D framework, demonstrating that the CPL was dominated by the original
molecular chirality rather than the global chirality of the hierarchical
structure. Moreover, the single-phase white-light materials with nearly
ideal CIE coordinates (0.33, 0.33) were constructed through the introduction
of dye emitters into Zn-CMOF (Zn-based chiral MOF). This work provided
not only an insightful view of the chirality transfer and disappearance
mechanism but also an efficient method for the preparation of the
highly porous CPL materials.