An electroluminescent device which comprises {HEAD ~ an organic luminescent layer} containing {TAIL ~ the organometallic luminescent material} comprising a compound of formula : 
An electroluminescent device which comprises { HEAD ~ an organic luminescent layer } containing { TAIL ~ the organometallic luminescent material } comprising a compound of formula :
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH