Structure and Emission Modulation of a Series of Cd(II) Luminescent Coordination Polymers through Guest Dependent Donor-Acceptor Interaction

摘要

Aimed at the exploration of luminescent coordination polymer (LCP) systems for highly tunable luminophores, a new series of Cd(II) LCPs, namely, [Cd-2(tpt)(2)(CBA)(2)(H2O)(2)]center dot(PAH) (1), [Cd-2(tpt)(2)(CBA)(2)]center dot(PAHs) (2-3) (tpt = 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine, H(2)CBA = 4-(carboxymethyl) benzoic acid, PAHs = polycyclic aromatic hydrocarbons, coronene for 1, perylene for 2, and triphenylene for 3), are successfully constructed based on the host-guest charge transfer (HGCT) mechanism. Through the PAHs directed coordination assembly of Cd(II) ions, CBA(2-) and tpt ligands, compounds 1-3 exhibit the as-expected host- guest structures, in which PAHs-tpt donor-acceptor (D-A) systems are successfully achieved. Structural investigations of 1-3 show that the flexibility of the carboxylate ligand and the guest dependent donor-acceptor interaction affect their structures. In addition, 1-3 exhibit a guest-dependent wide emission range originating from the charge-transfer interactions of the D-A systems. What is more, the overlap between the acceptor tpt and donor guests may affect the emission of the compounds in addition to the ionization potential (IP) of the PAH guests, which can help the understanding and targeted modulation of the emission properties in related systems.