Electroluminescent device

An electroluminescent device comprising a first electrode, a second electrode, and a layer comprising an electroluminescent compound between the first electrode and the second electrode wherein:

• the electroluminescent compound is selected from the group consisting of binuclear, trinuclear and polynuclear metal complexes in which nuclei are defined by at least two metal atoms, at least one of said metal atoms being selected from the group consisting of Sm (III), Eu (II), Eu (III), Tb (III), Dy(III), Yb (III), Lu (III), Gd (III), U(III), Tm (III), Ce (III), Pr (III), Nd (III), Pm (III), Dy (III), Ho (III), Er (III), and Yb (III), and at least a second of said metal atoms is selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium, germanium, tin, antimony, lead and metals of the first, second and third groups of transition metals;
• further wherein each metal atom is linked to another metal atom through a bridging ligand, said bridging ligands each having the general chemical formula:
• wherein:
• the groups R can be the same or different and are independently selected from the group consisting of hydrogen, substituted and unsubstituted aliphatic groups, substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbon groups and halogen atoms;
• Ar represents a substituted or unsubstituted aromatic or heteroaromatic group;
• and
• further wherein n is an integer from 1 to 10.