# Mixed Phenanthroline–Bipyridine Europium and Ytterbium CryptatesBright Luminophores with Small Radiative Lifetimes

## TL;DR

This paper introduces new europium and ytterbium complexes with high luminescence efficiency and short radiative lifetimes.

## Contribution

The novel use of phenanthroline and bipyridine-N,N′-dioxide creates highly efficient lanthanide cryptates with improved quantum yields.

## Key findings

- Phenanthroline-based cryptates show excellent luminescence efficiency in solution.
- Europium complexes achieve up to 20% absolute quantum yields in aqueous solution.
- The complexes exhibit small radiative lifetimes and efficient lanthanoid sensitization.

## Abstract

New phenanthroline-based
tris­(biaryl) europium­(III) and ytterbium­(III)
cryptates with great luminescence efficiencies in solution are reported.
1,10-Phenantroline, in combination with 2,2′-bipyridine-N,N′-dioxide, delivers cryptates
with high rigidity, efficient lanthanoid­(III) sensitization (ηsens) and small radiative lifetimes τrad for
Eu and Yb. The powerful synergy of both bidentate chelating units
results in excellent absolute quantum yields of up to 20% for the
europium complexes in aqueous solution, which indicates an impressive
improvement compared to other well-known tris­(bipyridyl)-based Eu­(III)
cryptates.