Controlled Synthesis of PdII and PtII Supramolecular Copolymer with Sequential Multiblock and Amplified Phosphorescence

Abstract

Supramolecular copolymers constitute a fundamental new class of functional materials attracting burgeoning interest, but examples that display phosphorescence and long-lived excited states are rare. Herein, we describe the synthesis of sequential phosphorescent multi-block supramolecular copolymers in one and multiple dimensions using pincer Pt II and Pd II complexes as building blocks by manipulating out-of-equilibrium self-assemblies via the living supramolecular polymerization approach. Doping a small amount of Pt II complexes (2 mol %) into the Pd II assemblies significantly boosted the emission efficiency and radiative decay rate constant (Φ em = 3.7%, k r = 1.8 × 10 4 s −1 in Pd II assemblies; Φ em = 76.2%, k r = 58.6 × 10 4 s −1 in Pt II-Pd II co-assemblies), which is ascribed to an external heavy-atom spin-orbital coupling effect arising from the doped Pt II complex with a delocalized 3[dσ∗→π∗] excited state. The findings on Pt II and Pd II supramolecular copolymers with controlled sequences and greatly enhanced phosphorescence efficiencies open the door to new photofunctional and responsive luminescent metal-organic supramolecular materials.