Ln(3)Q(9) as a Molecular Framework for Ion-Size-Driven Assembly of Heterolanthanide (Nd, Er, Yb) Multiple Near-Infrared Emitters

摘要

A unique example of discrete molecular entity Nd(y)Er(x)Yb(3-(x+y))Q(9) (1) (Q= quinolinolato) containing three different lanthanides simultaneously emitting in three different spectral regions in the NIR, ranging from 900 to 1600 nm, has been synthesized and fully chararacterized. A simple molecular strategy based on tuning metal composition in the Ln(3)Q(9) framework, which contains inequivalent central and terminal coordination sites, has allowed a satisfactory ion-size-driven control of molecular speciation close to 90 %. In 1 the central position of the larger Nd ion is well distinguished from the terminal ones of the smaller Yb3+ and Er3+, which are almost "vicariants" as found in the heterobimetallic Er(x)Yb(3-x)Q(9) (2). The Ln(3)Q(9) molecular architecture, which allows communication between the ions, has proved to afford multiple NIR emission in 1 and 2, and is promising to develop a variety of multifunctional materials through the variation of the Ln composition.