| abstract |
A compound having a formula M(L A ) x (L B ) y (L C ) z , where ligand L A is n n n n n n n n n n ligand L B is n n n n n n n n n n and L C is n n n n n n n n n n is disclosed. In formula M(L A ) x (L B ) y (L C ) z , M is a metal having an atomic number greater than 40; x is 1 or 2; y is 0, 1, or 2; z is 0, 1, or 2; x+y+z is the oxidation state of the metal M; A 1 -A 8 are carbon or nitrogen; ring B is bonded to ring A through a C—C bond; M is bonded to ring A through a M-C bond; X is O, S, Se, CRR′, or NR 1 ; rings C and D are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; R 3 represents mono, or di-substitution, or no substitution; R 2 , R C , and R D each independently represent mono, di, tri, or tetra-substitution, or no substitution;n R 4 represents mono, di, tri, or tetra-substitution; at least one R 4 is a five-membered or six-membered heterocyclic ring which can be further substituted by R E ; where R E represents mono, di, tri, or tetra-substitution, or no substitution; each R substituent is independently selected from a variety of moieties; and any adjacent R substitutents are optionally joined to form a ring. |