Organic electroluminescent materials and devices
A compound including a first bidentate ligand L A that includes a structure of Formula I, are provided. The ligand L A is coordinated to a metal M and can be joined with other ligands. In Formula I, in addition to some exclusions, each of X 1 , X 2 , X 3 , and X 4 is C or N; two R 1 , R 2 , and R 3 can be joined or fused to form a ring; and each R 1 , R 2 , and R 3 is independently a group containing the metal M, a hydrogen, or a General Substituent defined herein. Formulations, OLEDs, and consumer products containing the compound are also provided.
1 . A compound comprising a structure of Formula II,
which comprises a structure of Formula I,
wherein:
M is selected from the group consisting of Pd, Pt, and Au;
rings A, B, C, and D are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;
each of X 1 to X 12 is independently C, B, or N;
each of Z 1 , Z 2 , Z 3 , and Z 4 is independently C, B, or N;
each of L 1 , L 2 , L 3 , and L 4 is independently selected from the group consisting of a direct bond, O, S, Se, NR, BR, BRR′, CRR′, SiRR′, GeRR′, a portion of Ring 1, and Ring 1;
each of a, b, c, and d is independently 0 or 1;
a+b+c+d=3 or 4;
when a is 0, X 6 is substituted by R A and X 7 is substituted by R B ;
when b is 0, X 8 is substituted by R B and X 9 is substituted by R C ;
when c is 0, X 10 is substituted by R C and X 11 is substituted by R D ;
when d is 0, X 5 is substituted by R A and X 12 is substituted by R D ;
K 1 , K 2 , K 3 , and K 4 are each independently selected from the group consisting of a direct bond, O, and S;
each of Z 1 , Z 2 , Z 3 , and Z 4 that is connected to O or S is C;
R 3 , R A , R B , R C , and R D each independently represents mono to the maximum allowable substitution, or no substitution;
each R, R′, R A , R B , R C , and R D is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof,
wherein each R 1 , R 2 , and R 3 is independently a group containing a metal M, a hydrogen, or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof,
any two adjacent R 1 , R 2 , R 3 , R, R′, R A , R B , R C , and R D can be joined or fused together to form a ring;
if R 3 at X 1 and X 2 are fused together to form a ring, and R 3 at X 3 and X 4 are fused together to form a ring, then the rings are not both joined to the metal M forming a 5-membered chelate ring;
if M is Pt and R 3 at X 3 and X 4 are fused together to form a six-membered ring, then R 3 at X 1 and X 2 are not fused together to form a six-membered ring; and
wherein at least one of the following is true:
(1) Ring 1 is fused to one of ring A, ring B, ring C, or ring D; or
(2) Ring 1 is fused to any ring or ring system already fused to one of ring A, ring B, ring C, or ring D.
2 . The compound of claim 1 , wherein each R 1 , R 2 , and R 3 is independently a hydrogen, or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, combinations thereof, and combinations that include the metal M; and
each R, R′, R A , R B , R C , and R D is independently a hydrogen, or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.
3 . The compound of claim 1 , wherein each of X 1 , X 2 , X 3 , and X 4 is C.
4 . The compound of claim 1 , wherein Ring 1 is fused to one of ring A, ring B, ring C, or ring D.
5 . The compound of claim 1 , wherein Ring 1 is fused to any ring or ring system already fused to one of one of ring A, ring B, ring C, or ring D.
6 . The compound of claim 1 , wherein the compound is selected from the group consisting of compounds having the formula of Pt(L A′ )(Ly):
wherein L A′ is selected from LIST A1 or LIST A2;
wherein LIST A1 has the following structures
wherein LIST A2 has the following structures:
wherein L y is selected from the group consisting of LIST B1 and LIST B2;
wherein LIST B1 has the following structures:
wherein LIST B2 has the following structures:
with the proviso that if L A′ is selected from LIST A1, then Ly is selected from LIST B1 or LIST B2, and if L A is selected from LIST A2, then Ly is selected from LIST B1;
wherein each R A1 , R B1 , R C1 , R X1 , R X2 , R E , R F , R X , and R Y is independently selected from the group consisting of:
wherein Ph is phenyl.
7 . The compound of claim 6 , wherein the compound is selected from the group consisting of the compounds having the formula of Pt(L A′ )(Ly):
wherein L A′ is selected from the group consisting of L A′ 7-(Ri)(Rj)(Rk), L A′ 10-(Ri)(Rj)(Rk) to L A′ 14-(Ri)(Rj)(Rk), L A′ 15-(Ri)(Rj)(Rk)(Rl), L A′ 16-(Ri)(Rj)(Rk) to L A′ 34-(Ri)(Rj)(Rk), L A′ 37-(Ri)(Rj)(Rk) to L A′ 38-(Ri)(Rj)(Rk), L A′ 39-(Ri)(Rj)(Rk)(Rl), L A′ 40-(Ri)(Rj)(Rk), L A′ 41-(Ri)(Rj)(Rk)(RL), L A′ 42-(Ri)(Rj)(Rk) to L A′ 44-(Ri)(Rj)(Rk), L A′ 45-(Ri)(Rj)(Rk)(Rl), L A′ 46-(Ri)(Rj)(Rk), L A′ 47-(Ri)(Rj)(Rk)(Rl), and L A′ 48-(Ri)(Rj)(Rk), wherein each of i, j, k, and l is independently an integer from 1 to 70; wherein structures of L A′ 1-(Rl)(Rl)(RI) to L A′ 54-(R72)(R72)(R72) are defined as follows:
L A’
Structure of L A’
L A’ 7-(Ri)(Rj)(Rk), wherein L A’ 7-(R1)(R1)(R1) to L A’ 7-(R72)(R72)(R72) have the structure
L A’ 10-(Ri)(Rj)(Rk), wherein L A’ 10-(R1)(R1)(R1) to L A’ 10-(R72)(R72)(R72) have the structure
L A’ 11-(Ri)(Rj)(Rk), wherein L A’ 11-(R1)(R1)(R1) to L A’ 11-(R72)(R72)(R72) have the structure
L A’ 12-(Ri)(Rj)(Rk), wherein L A’ 12-(R1)(R1)(R1) to L A’ 12-(R72)(R72)(R72) have the structure
L A’ 13-(Ri)(Rj)(Rk), wherein L A’ 13-(R1)(R1)(R1) to L A’ 13-(R72)(R72)(R72) have the structure
L A’ 14-(Ri)(Rj)(Rk), wherein L A’ 14-(R1)(R1)(R1) to L A’ 14-(R72)(R72)(R72) have the structure
L A’ 15-(Ri)(Rj)(Rk)(Rl), wherein L A’ 15-(R1)(R1)(R1)(R1) to L A’ 15-(R72)(R72)(R72)(R72) have the structure
L A’ 16-(Ri)(Rj)(Rk), wherein L A’ 16-(R1)(R1)(R1) to L A’ 16-(R72)(R72)(R72) have the structure
L A’ 17-(Ri)(Rj)(Rk), wherein L A’ 17-(R1)(R1)(R1) to L A’ 17-(R72)(R72)(R72) have the structure
L A’ 18-(Ri)(Rj)(Rk), wherein L A’ 18-(R1)(R1)(R1) to L A’ 18-(R72)(R72)(R72) have the structure
L A’ 19-(Ri)(Rj)(Rk), wherein L A’ 19-(R1)(R1)(R1) to L A’ 19-(R72)(R72)(R72) have the structure
L A’ 20-(Ri)(Rj)(Rk), wherein L A’ 20-(R1)(R1)(R1) to L A’ 20-(R72)(R72)(R72) have the structure
L A’ 21-(Ri)(Rj)(Rk), wherein L A’ 21-(R1)(R1)(R1) to L A’ 21-(R72)(R72)(R72) have the structure
L A’ 22-(Ri)(Rj)(Rk), wherein L A’ 22-(R1)(R1)(R1) to L A’ 22-(R72)(R72)(R72) have the structure
L A’ 23-(Ri)(Rj)(Rk), wherein L A’ 23-(R1)(R1)(R1) to L A’ 23-(R72)(R72)(R72) have the structure
L A’ 24-(Ri)(Rj)(Rk), wherein L A’ 24-(R1)(R1)(R1) to L A’ 24-(R72)(R72)(R72) have the structure
L A’ 25-(Ri)(Rj)(Rk), wherein L A’ 25-(R1)(R1)(R1) to L A’ 25-(R72)(R72)(R72) have the structure
L A’ 26-(Ri)(Rj)(Rk), wherein L A’ 26-(R1)(R1)(R1) to L A’ 26-(R72)(R72)(R72) have the structure
L A’ 27-(Ri)(Rj)(Rk), wherein L A’ 27-(R1)(R1)(R1) to L A’ 27-(R72)(R72)(R72) have the structure
L A’ 28-(Ri)(Rj)(Rk), wherein L A’ 28-(R1)(R1)(R1) to L A’ 28-(R72)(R72)(R72) have the structure
L A’ 29-(Ri)(Rj)(Rk), wherein L A’ 29-(R1)(R1)(R1) to L A’ 29-(R72)(R72)(R72) have the structure
L A’ 30-(Ri)(Rj)(Rk), wherein L A’ 30-(R1)(R1)(R1) to L A’ 30-(R72)(R72)(R72) have the structure
L A’ 31-(Ri)(Rj)(Rk), wherein L A’ 31-(R1)(R1)(R1) to L A’ 31-(R72)(R72)(R72) have the structure
L A’ 32-(Ri)(Rj)(Rk), wherein L A’ 32-(R1)(R1)(R1) to L A’ 32-(R72)(R72)(R72) have the structure
L A’ 33-(Ri)(Rj)(Rk), wherein L A’ 33-(R1)(R1)(R1) to L A’ 33-(R72)(R72)(R72) havethe structure
L A’ 34-(Ri)(Rj)(Rk), wherein L A’ 34-(R1)(R1)(R1) to L A’ 34-(R72)(R72)(R72) have the structure
L A’ 37-(Ri)(Rj)(Rk), wherein L A’ 37-(R1)(R1)(R1) to L A’ 37-(R72)(R72)(R72) have the structure
L A’ 38-(Ri)(Rj)(Rk), wherein L A’ 38-(R1)(R1)(R1) to L A’ 38-(R72)(R72)(R72) have the structure
L A’ 39-(Ri)(Rj)(Rk)(Rl), wherein L A’ 39-(R1)(R1)(R1)(R1) to L A’ 39-(R72)(R72)(R72)(R72) have the structure
L A’ 40-(Ri)(Rj)(Rk), wherein L A’ 40-(R1)(R1)(R1) to L A’ 40-(R72)(R72)(R72) have the structure
L A’ 41-(Ri)(Rj)(Rk)(Rl), wherein L A’ 41-(R1)(R1)(R1)(R1) to L A’ 41-(R72)(R72)(R72)(R72) have the structure
L A’ 42-(Ri)(Rj)(Rk), wherein L A’ 42-(R1)(R1)(R1) to L A’ 42-(R72)(R72)(R72) have the structure
L A’ 43-(Ri)(Rj)(Rk), wherein L A’ 43-(R1)(R1)(R1) to L A’ 43-(R72)(R72)(R72) have the structure
L A’ 44-(Ri)(Rj)(Rk), wherein L A’ 44-(R1)(R1)(R1) to L A’ 44-(R72)(R72)(R72) have the structure
L A’ 45-(Ri)(Rj)(Rk)(Rl), wherein L A’ 45-(R1)(R1)(R1)(R1) to L A’ 45-(R72)(R72)(R72)(R72) have the structure
L A’ 46-(Ri)(Rj)(Rk), wherein L A’ 46-(R1)(R1)(R1) to L A’ 46-(R72)(R72)(R72) have the structure
L A’ 47-(Ri)(Rj)(Rk), wherein L A’ 47-(R1)(R1)(R1) to L A’ 47-(R72)(R72)(R72) have the structure
L A’ 48-(Ri)(Rj)(Rk), wherein L A’ 48-(R1)(R1)(R1) to L A’ 48-(R72)(R72)(R72) have the structure
wherein L y is selected from the group consisting of L y 1-(Ro)(Rp)(Rq) to L y 33-(Ro)(Rp)(Rq), wherein each of o, p, and q is independently an integer from 1 to 70; wherein structures of L y 1-(R1)(R1)(R1) to L y 33-(R72)(R72)(R72) are defined as follows:
L y
Structure of L y
L y 1-(Ro)(Rp)(Rq), wherein L y 1- (R1)(R1)(R1) to L y 1- (R72)(R72)(R72) have the structure
L y 2-(Ro)(Rp)(Rq), wherein L y 2- (R1)(R1)(R1) to L y 2- (R72)(R72)(R72) have the structure
L y 3-(Ro)(Rp)(Rq), wherein L y 3- (R1)(R1)(R1) to L y 3- (R72)(R72)(R72) have the structure
L y 4-(Ro)(Rp)(Rq), wherein L y 4- (R1)(R1)(R1) to L y 4- (R72)(R72)(R72) have the structure
L y 5-(Ro)(Rp)(Rq), wherein L y 5- (R1)(R1)(R1) to L y 5- (R72)(R72)(R72) have the structure
L y 6-(Ro)(Rp)(Rq), wherein L y 6- (R1)(R1)(R1) to L y 6- (R72)(R72)(R72) have the structure
L y 7-(Ro)(Rp)(Rq), wherein L y 7- (R1)(R1)(R1) to L y 7- (R72)(R72)(R72) have the structure
L y 8-(Ro)(Rp)(Rq), wherein L y 8- (R1)(R1)(R1) to L y 8- (R72)(R72)(R72) have the structure
L y 9-(Ro)(Rp)(Rq), wherein L y 9- (R1)(R1)(R1) to L y 9- (R72)(R72)(R72) have the structure
L y 10-(Ro)(Rp)(Rq), wherein L y 10- (R1)(R1)(R1) to L y 10- (R72)(R72)(R72) have the structure
L y 11-(Ro)(Rp)(Rq), wherein L y 11- (R1)(R1)(R1) to L y 11- (R72)(R72)(R72) have the structure
L y 12-(Ro)(Rp)(Rq), wherein L y 12- (R1)(R1)(R1) to L y 12- (R72)(R72)(R72) have the structure
L y 13-(Ro)(Rp)(Rq), wherein L y 13- (R1)(R1)(R1) to L y 13- (R72)(R72)(R72) have the structure
L y 14-(Ro)(Rp)(Rq), wherein L y 14- (R1)(R1)(R1) to L y 14- (R72)(R72)(R72) have the structure
L y 15-(Ro)(Rp)(Rq), wherein L y 15- (R1)(R1)(R1) to L y 15- (R72)(R72)(R72) have the structure
L y 16-(Ro)(Rp)(Rq), wherein L y 16- (R1)(R1)(R1) to L y 16- (R72)(R72)(R72) have the structure
L y 17-(Ro)(Rp)(Rq), wherein L y 17- (R1)(R1)(R1) to L y 17- (R72)(R72)(R72) have the structure
L y 18-(Ro)(Rp)(Rq), wherein L y 18- (R1)(R1)(R1) to L y 18- (R72)(R72)(R72) have the structure
L y 19-(Ro)(Rp)(Rq), wherein L y 19- (R1)(R1)(R1) to L y 19- (R72)(R72)(R72) have the structure
L y 20-(Ro)(Rp)(Rq), wherein L y 20- (R1)(R1)(R1) to L y 20- (R72)(R72)(R72) have the structure
L y 21-(Ro)(Rp)(Rq), wherein L y 21- (R1)(R1)(R1) to L y 21- (R72)(R72)(R72) have the structure
L y 22-(Ro)(Rp)(Rq), wherein L y 22- (R1)(R1)(R1) to L y 22- (R72)(R72)(R72) have the structure
L y 23-(Ro)(Rp)(Rq), wherein L y 23- (R1)(R1)(R1) to L y 23- (R72)(R72)(R72) have the structure
L y 24-(Ro)(Rp)(Rq), wherein L y 24- (R1)(R1)(R1) to L y 24- (R72)(R72)(R72) have the structure
L y 25-(Ro)(Rp)(Rq), wherein L y 25- (R1)(R1)(R1) to L y 25- (R72)(R72)(R72) have the structure
L y 26-(Ro)(Rp)(Rq), wherein L y 26- (R1)(R1)(R1) to L y 26- (R72)(R72)(R72) have the structure
L y 27-(Ro)(Rp)(Rq), wherein L y 27- (R1)(R1)(R1) to L y 27- (R72)(R72)(R72) have the structure
L y 28-(Ro)(Rp)(Rq), wherein L y 28- (R1)(R1)(R1) to L y 28- (R72)(R72)(R72) have the structure
L y 29-(Ro)(Rp)(Rq), wherein L y 29- (R1)(R1)(R1) to L y 29- (R72)(R72)(R72) have the structure
L y 30-(Ro)(Rp)(Rq), wherein L y 30- (R1)(R1)(R1) to L y 30- (R72)(R72)(R72) have the structure
L y 31-(Ro)(Rp)(Rq), wherein L y 31- (R1)(R1)(R1) to L y 31- (R72)(R72)(R72) have the structure
L y 32-(Ro)(Rp)(Rq), wherein L y 32- (R1)(R1)(R1) to L y 32- (R72)(R72)(R72) have the structure
L y 33-(Ro)(Rp)(Rq), wherein L y 33- (R1)(R1)(R1) to L y 33- (R72)(R72)(R72) have the structure
wherein Ph is phenyl; and
wherein R1 to R72 have the following structures:
8 . The compound of claim 6 , wherein L A′ is selected from the group consisting of:
9 . The compound of claim 8 , wherein L y is selected from the group consisting of:
10 . The compound of claim 8 , wherein L y is
11 . The compound of claim 1 , wherein the compound has a structure selected from the group consisting of:
wherein R E represents mono to the maximum allowable substitution, or no substitution, and
each R E is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof.
12 . The compound of claim 11 , wherein the compound has a structure of:
13 . The compound of claim 12 , wherein d is 0.
14 . The compound of claim 13 , wherein b is 1, and L 2 is O.
15 . The compound of claim 14 , wherein ring A is imidazole-derived carbene and Z 1 is carbene C.
16 . The compound of claim 1 , wherein the compound is selected from the group consisting of:
17 . An organic light emitting device (OLED) comprising:
an anode;
a cathode; and
an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound comprising a structure of Formula II,
which comprises a structure of Formula I,
wherein:
M is selected from the group consisting of Pd, Pt, and Au;
rings A, B, C, and D are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;
each of X 1 to X 12 is independently C, B, or N;
each of Z 1 , Z 2 , Z 3 , and Z 4 is independently C, B, or N;
each of L 1 , L 2 , L 3 , and L 4 is independently selected from the group consisting of a direct bond, O, S, Se, NR, BR, BRR′, CRR′, SiRR′, GeRR′, a portion of Ring 1, and Ring 1;
each of a, b, c, and d is independently 0 or 1;
a+b+c+d=3 or 4;
when a is 0, X 6 is substituted by R A and X 7 is substituted by R B ;
when b is 0, X 8 is substituted by R B and X 9 is substituted by R C ;
when c is 0, X 10 is substituted by R C and X 11 is substituted by R D ;
when d is 0, X 5 is substituted by R A and X 12 is substituted by R D ;
K 1 , K 2 , K 3 , and K 4 are each independently selected from the group consisting of a direct bond, O, and S;
each of Z 1 , Z 2 , Z 3 , and Z 4 that is connected to O or S is C;
R 3 , R A , R B , R C , and R D each independently represents mono to the maximum allowable substitution, or no substitution;
each R, R′, R A , R B , R C , and R D is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
wherein each R 1 , R 2 , and R 3 is independently a group containing a metal M, a hydrogen, or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof,
any two adjacent R 1 , R 2 , R 3 , R, R′, R A , R B , R C , and R D can be joined or fused together to form a ring;
if R 3 at X 1 and X 2 are fused together to form a ring, and R 3 at X 3 and X 4 are fused together to form a ring, then the rings are not both joined to the metal M forming a 5-membered chelate ring;
if M is Pt and R 3 at X 3 and X 4 are fused together to form a six-membered ring, then R 3 at X 1 and X 2 are not fused together to form a six-membered ring; and
wherein at least ono of the following is true:
(1) Ring 1 is fused to one of ring A, ring B, ring C, or ring D; or
(2) Ring 1 is fused to any ring or ring system already fused to one of ring A, ring B, ring C, or ring D.
18 . The OLED of claim 17 , wherein the organic layer further comprises a host, wherein host comprises at least one chemical moiety selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).
19 . The OLED of claim 17 , wherein the host is selected from the group consisting of
and combinations thereof.
20 . A consumer product comprising an organic light-emitting device comprising:
an anode;
a cathode; and
an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound comprising a structure of Formula II,
which comprises a structure of Formula I,
wherein:
M is selected from the group consisting of Pd, Pt, and Au;
rings A, B, C, and D are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;
each of X 1 to X 12 is independently C, B, or N;
each of Z 1 , Z 2 , Z 3 , and Z 4 is independently C, B, or N;
each of L 1 , L 2 , L 3 , and L 4 is independently selected from the group consisting of a direct bond, O, S, Se, NR, BR, BRR′, CRR′, SiRR′, GeRR′, a portion of Ring 1, and Ring 1;
each of a, b, c, and d is independently 0 or 1;
a+b+c+d=3 or 4;
when a is 0, X 6 is substituted by R A and X 7 is substituted by R B ;
when b is 0, X 8 is substituted by R B and X 9 is substituted by R C ;
when c is 0, X 10 is substituted by R C and X 11 is substituted by R D ;
when d is 0, X 5 is substituted by R A and X 12 is substituted by R D ;
K 1 , K 2 , K 3 , and K 4 are each independently selected from the group consisting of a direct bond, O, and S;
each of Z 1 , Z 2 , Z 3 , and Z 4 that is connected to O or S is C;
R 3 , R A , R B , R C , and R D each independently represents mono to the maximum allowable substitution, or no substitution;
each R, R′, R A , R B , R C , and R D is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
wherein each R 1 , R 2 , and R 3 is independently a group containing a metal M, a hydrogen, or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, germyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof,
any two adjacent R 1 , R 2 , R 3 , R, R′, R A , R B , R C , and R D can be joined or fused together to form a ring;
if R 3 at X 1 and X 2 are fused together to form a ring, and R 3 at X 3 and X 4 are fused together to form a ring, then the rings are not both joined to the metal M forming a 5-membered chelate ring;
if M is Pt and R 3 at X 3 and X 4 are fused together to form a six-membered ring, then R 3 at X 1 and X 2 are not fused together to form a six-membered ring; and
wherein at least one of the following is true:
(1) Ring 1 is fused to one of ring A, ring B, ring C, or ring D; or
(2) Ring 1 is fused to any ring or ring system already fused to one of ring A, ring B, ring C, or ring D.