Assembly of a trapped valent Ce III/IV -TCNQ complex through metal-ligand redox cooperativity.

Complex (Cp 3 Ce IV ) 2 (TCNQ)(Ce III Cp 3 ) 2 (1) was prepared by reducing neutral TCNQ 0 (tetracyanoquinodimethane) with Cp 3 Ce(THF). Two types of cerium centres with a dianionic TCNQ 2- moiety are present in 1, wherein each of the four cyano-groups are bound by a cation. Formation of this trapped-valent organocerium compound 1 is facilitated by metal-ligand redox cooperativity. Characterization of 1 was carried out using structural-, magnetometry-, and IR-spectroscopic analyses. Photophysical studies on this compound reveal Ce III luminescence, and opens up avenues for promising multifunctional, mixed-valent lanthanide materials.