Mausolates†: Large-Cavity Chelates with Potential as Delivery Vehicles in Nuclear Medicine.

A new type of diborate clathrochelate (cage) ligand featuring nine inwardly pointing nitrogen donors that form a large, rigid cavity, termed a mausolate, is presented. The cavity size and high denticity make this an attractive delivery vehicle for large radionuclides in nuclear medicine. Metal mausolate complexes are stable to air and water (neutral pH) and display extremely high thermal stability (> 400 0C). Lanthanide uptake by the mausolate ligand occurs rapidly in solution at room temperature and once complexed, the lanthanide ions are not displaced by a 250-fold excess of a competitive lanthanide salt over more than one week.

Red-Shifted Emission in Multiple Resonance Thermally Activated Delayed Fluorescent Materials through Malononitrile Incorporation.

Multiple resonance thermally activated delayed fluorescent (MR-TADF) materials offer higher color purity than conventional TADF materials but suffer from aggregation-caused quenching (ACQ) and rarely exhibit red emission. Herein, two malononitrile-substituted emitters are synthesized from a quinolino[3,2,1-de]acridine-5,9-dione (QAO) MR-TADF precursor. Both materials maintain MR-TADF, while they display red-shifted fluorescence. They also overcome ACQ, displaying enhanced emission upon aggregation in solution and forming red-emissive J-aggregates in the solid state with photoluminescent quantum yields of 9 and 11%.