Patent ID: 7989089

Claim:
A compound represented by formula (1) wherein X 1 , X 2 , X 3 and X 4 are nitrogen; Y is selected from the group consisting of a substituted or unsubstituted aryl group, and a substituted or unsubstituted aliphatic group having 1-24 carbon atoms which may be straight, branched or cyclic; Z is a substituted or unsubstituted aryl moiety selected from the group consisting of phenyl, biphenyl, naphthyl, anthryl, phenanthryl, pyrenyl, pyridyl, bipyridyl, indyl, and quinolinyl; and wherein a said substituent is selected from the group consisting of an aryl group, an alkoxy group, a hydroxy group, a halo group, a nitro group, a nitrile group, —CF 3 and an aliphatic group having 1-24 carbon atoms which may be straight, branched or cyclic.