In accordance with {HEAD ~ the present invention}, there is provided an organometallic luminescent material selected from {TAIL ~ the group} consisting of the compounds of formulae to  
In accordance with { HEAD ~ the present invention } , there is provided an organometallic luminescent material selected from { TAIL ~ the group } consisting of the compounds of formulae to
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH