| abstract |
Compounds having the formula M(L A ) x (L B ) y (L C ) z , devices containing the same, and formulations containing the same are described. The compounds include: n n n n n n n n n n n n where M is a metal having an atomic number greater than 40; x is 1, or 2; y is 1, or 2; and z is 0, 1, or 2; where x+y+z is the oxidation state of the metal M, where X 1 , X 2 , X 3 , and X 4 are C or N; where at least one of R 1 , R 2 , R 3 , and R 4 has at least two C atoms; where R B represents di, tri, or tetra-substitution, and where two adjacent R B for a six-member carbocyclic or heterocyclic ring E fused to ring B; where, when ring E is heterocyclic, the only heteroatom is nitrogen; where ring E can be further substituted; and where (a) at least one of X 1 , X 2 , X 3 , and X 4 is N, (b) ring E is heterocylic, or (c) both. |