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.