A new class of lanthanide complexes exhibiting metal-based visible and near-IR photoluminescence has been designed, synthesized and characterized. A pair of highly conjugated electropolymerizable ligands were produced via condensation reactions between 3,4 - (ethylenedioxy)thiophene and dipyriddophenazine (EDOT2dppz) or dipyriddoquinaxoline (EDOT2dpq). Luminescent analysis indicated that the structural differences of (EDOT2dppz) and (EDOT2dpq) have little effect on the triplet excited state energy levels of the ligands. Two triplet excited state energy levels were observed for each ligand at approximately 320 and 500 nm, both of which were investigated for possible lanthanide sensitization. A series of (�-diketonate)3Ln(III) (EDOT2dpq/EDOT2dppz) complexes was produced in order to probe the potential of the ligands to sensitize visible and near-IR Ln(III) emission. Excitation of the higher energy triplet excited state level at ~320 nm lead to lanthanide-based emission from Tb(III), Dy(III), and Eu(III) complexes. Above average emission (QY = 2-8%) and long lifetimes (24-29 �s) were observed from the Dy(III) complexes. Terbium complexes displayed quantum yields between 21-36% and lifetimes from 636-888 �s. Electropolymerization of the Tb(III) monomers resulted in conducting metallopolymers with metal-based emission ranging from quantum yields of 0.01�0.03%. Excitation of the lower energy triplet excited state level at ~500 nm lead to effective sensitization of near-IR emitting Yb(III) complexes. Yb(III) emission in the complexes was observed with quantum yields of up to 5.3% and lifetimes as long as 29.4 �s. The metal-containing monomers were electropolymerized and Yb(III)-based emission was observed from the metallopolymer with quantum yields of ~0.3% and lifetimes of ~14.6 �s. This work indicates that (EDOT2dppz) and (EDOT2dpq) ligands are effective sensitizers of visible and near-IR emission in both lanthanide-containing monomers and conducting metallopolymers.

Highly conjugated electropolymerizable antenna ligands for the sensitization of near-IR and visible Ln(III) emission

247th National Meeting (2014)

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