Patent ID: 7462405

Claim:
An electroluminescent device comprising a light-emitting layer containing a light emitting phosphorescent material that contains an organometallic complex comprising a metal selected from the group consisting of Mo, W, Re, Ru, and Os that is coordinated to a neutral or negatively-charged ligand group through the π electrons of the ligand with a hapticity greater than 2 wherein the light-emitting layer contains a light emitting compound of Formula (1), wherein: M represents Mo, W, Re, Ru, or Os, Z represents the atoms necessary to form a ligand group that is neutral or negatively charged and Z is coordinated to M though π electron density with a hapticity greater than 2; L represents independently selected ligand groups, provided that L is chosen so as to create a neutral complex with 18 electrons in the valence shell of M; and n is 1-4, as necessary to fulfill the requirements of a neutral complex with 18 electrons in the valence shell of M provided that Z is represented by Formula (2), wherein: B represents the atoms necessary to complete a 5- or 6-membered aromatic ring group that is complexed to M through π electron density on B; and X represents a substituent group that comprises a conjugated system.