A compound comprising a ligand L.sub.A, having a structure of Formula I,

##STR00001##

is provided. In Formula I, A.sup.1 to A.sup.8 are each independently CR or N; at least two adjacent ones of A.sup.1 to A.sup.8 are CR and the Rs are joined together to form a six-membered ring fused to ring A or ring C; X is O, S, or Se; each R and R.sup.B is independently hydrogen or a substituent; any adjacent substituents are optionally joined or fused into a ring; the ligand L.sub.A is coordinated to a metal M; the metal M is bonded to ring A through a M-C bond; the metal M can be coordinated to other ligands; and the ligand L.sub.A is optionally linked with other ligands. Formulations, OLEDs, and consumer products containing such compounds are also disclosed.

A compound having the formula Ir(L.sub.A).sub.n(L.sub.B).sub.3−n, having the structure ##STR00001##
Formula I, is disclosed. In Formula I, each of Z.sup.1, Z.sup.2, Z.sup.3, and Z.sup.4 is CR.sup.2; X is O, S, or Se; n is an integer from 1 to 3; R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 each independently represent mono- to a maximum possible number of substitutions, or no substitution; R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are each independently selected from a variety of substituents; any two substitutions in R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are optionally joined to form a ring; at least one pair of substitutions in R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are joined together to form a bridge structure comprising a backbone structure that forms a fused first ring, which can be further substituted; and the backbone structure is saturated. Organic light emitting devices and consumer products containing the compounds are also disclosed.

A compound comprising a first ligand L.sub.A of Formula I, ##STR00001##
is disclosed. In the structure of Formula I, ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z.sup.1-Z.sup.4 are each independently C or N; at least two consecutive Z.sup.1-Z.sup.4 are C, and are fused to a structure of Formula II ##STR00002##
or Formula III ##STR00003##
Y.sup.1; Y.sup.1 and Y.sup.2 are each independently O, S, Se, CRR′, SiRR′, or GeRR′; each R.sup.A, R.sup.B, R.sup.C, R, and R′ is a hydrogen or a substituent; and any two substituents may be joined or fused together to form a ring. In the compound, L.sub.A is complexed to a metal M by the dashed lines in Formula I to form a five-membered chelate ring, and M has an atomic weight greater than 40. Organic light emitting devices and consumer products containing the compounds are also disclosed.

A composition is disclosed that includes a first compound capable of functioning as a host in an emissive layer of an OLED at room temperature; and a second compound that includes a ligand L.sub.A of Formula III ##STR00001##
where ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; where R represents two adjacent substituents that are joined together to form a ring that is fused to ring B, and R has a structure of Formula IV ##STR00002##
or Formula V ##STR00003##
disclosed herein.

A compound is disclosed that is selected from the group consisting of a structure having Formula I ##STR00001##
and a structure having Formula II ##STR00002##

Provided are an organometallic compound represented by Formula 1 and an organic light-emitting device including the same. The organic light-emitting device includes a first electrode; a second electrode facing the first electrode; an organic layer between the first electrode and the second electrode and including an emission layer; and at least one organometallic compound represented by Formula 1.

An organometallic compound represented by Formula 1:

M(L.sub.1).sub.n1(L.sub.2).sub.n2  Formula 1

wherein, M is a transition metal, L.sub.1 and L.sub.2 are ligands as provided herein, n1 and n2 are each independently 1 or 2, the sum of n1 and n2 is 2 or 3, and L.sub.1 is different from L.sub.2.

Provided are organometallic compounds including a ligand L.sub.A of Formula I ##STR00001##

Embodiments in accordance with the present invention encompass compositions encompassing a latent organo-ruthenium compound, a pyridine compound, a photosensitizer and an ultra violet light blocking compound along with one or more monomers which undergo ring open metathesis polymerization (ROMP) when said composition is exposed to suitable actinic radiation to form a substantially transparent film or a three dimensional object. Surprisingly, the compositions are very stable at ambient conditions to temperatures up to 80° C. for several days and undergo mass polymerization only when subjected to actinic radiation under inert atmosphere such as for example a blanket of nitrogen. Accordingly, compositions of this invention are useful in various opto-electronic applications, including as 3D printing materials, coatings, encapsulants, fillers, leveling agents, among others.

Provided are organometallic compounds comprising a first ligand L.sub.A comprising a multicyclic fused ring system wherein ligand L.sub.A is coordinated to a metal M; and wherein M is selected from the group consisting of Os, Ir, Pd, Pt, Cu, Ag, and Au. Also provided are formulations comprising these compounds. Further provided are OLEDs and related consumer products that utilize these compounds.