According to one embodiment, a compound comprising a ligand L
A
of Formula I
is described. In the structure of Formula I, A
1
through A
8
are independently carbon or nitrogen, with at least one being nitrogen; X
1
is selected from the group consisting of O, S, and Se; X
2
and X
3
are independently selected from the group consisting of C, N, O, P, and S; ring A is a 5- or 6-membered heterocyclic ring bonded to ring B through a X
2
—C bond and bonded to M through a metal-carbene bond; any adjacent substitutions in R
1
and R
2
are optionally linked together to form a ring; the ligand L
A
is coordinated to a metal M; and the ligand L
A
is optionally linked with other ligands to comprise up to a hexadentate ligand. Formulations and devices, such as an OLEDs, that include the compound comprising ligand L
A
of formula I are also described.
根据一种实施例,描述了一种包含
配体LA的化合物,其具有公式I中的
配体LA。在公式I的结构中,A1到A8独立地是碳或氮,其中至少有一个是氮;X1选择自O、S和Se组成的群;X2和X3独立地选择自C、N、O、P和S组成的群;环A是通过X2-C键与环B连接,通过
金属卡宾键与M连接的5-或6成员杂环;R1和R2中的任何相邻取代基可选择地连接在一起形成环;
配体LA与
金属M配位;并且
配体LA可选择地与其他
配体连接以形成高达六齿
配体。还描述了包括公式I中
配体LA的化合物的制剂和设备,例如OLEDs。