Host–Guest Engineering of Coordination Polymers for Highly Tunable Luminophores Based on Charge Transfer Emissions

Aiming
at the targeted construction of coordination polymer luminophores,
the engineering of host–guest architectures with charge transfer
based emissions is performed by utilizing the interactions between
the electron-deficient 2,4,6-tri­(pyridin-4-yl)-1,3,5-triazine (tpt)
and electron-rich polycyclic aromatic hydrocarbons (PAHs) motifs as
acceptors and donors, respectively. Through guest modulation of a
prototype coordination polymer [Cd­(tpt)­(1,4-pda)­(H2O)2]·(tpt)·(H2O)2 (1) (1,4-H2pda = 1,4-phenylene­diacetic acid), a series
of coordination polymers with different PAHs as guests, [Cd2(tpt)2(1,4-pda)2]·guest (2–5) (guest = triphenylene for 2,
pyrene for 3, coronene for 4, and perylene
for 5), are successfully fabricated. Distinct from 1, coordination polymers 2–5 reveal unique bilayer structures with PAHs interlayer and good
stability, owing to the enhanced stacking interactions between tpt
motifs and PAH guests. Moreover, their emissions cover a wide range
of wavelength due to the effective guest to host charge transfer interactions
between donor and acceptor motifs. Their readily tunable host–guest
charge transfer based emissions make them good candidates as potential
luminophores.