Synthesis of Inert Homo- and Heterodinuclear Rare-Earth Cryptates.

A new ditopic cryptand based on two tris(biaryl)-based binding pockets bridged by a 2,2'-bipyrimidine unit enables the selective synthesis of homo- and heterodinuclear rare-earth cryptates, which are kinetically inert under challenging conditions and can even be purified by preparative high-performance liquid chromatography.