Organometallic compound, organic light- emitting device including the same, and electronic apparatus including the organic light- emitting device
An organometallic compound represented by Formula 1: M(L 1 ) n1 (L 2 ) n2 Formula 1 wherein M is a transition metal, L 1 is a ligand represented by Formula 2 as provided herein, n1 is 1, 2, or 3, wherein, when n1 is 2, two L 1 groups are identical to or different from each other, and when n1 is 3, two or more of three L 1 groups are different from each other, L 2 is a monodentate ligand, a bidentate ligand, a tridentate ligand, or a tetradentate ligand, and n2 is 0, 1, 2, 3, or 4, wherein, when n2 is 2 or greater, two or more L 2 groups are identical to or different from each other, and L 1 and L 2 are different from each other.
1. An organometallic compound represented by Formula 1:
M(L 1 ) n1 (L 2 ) n2 Formula 1
wherein, in Formula 1,
M is a transition metal,
L 1 is a ligand represented by Formula 2,
n1 is 1 or 2, wherein, when n1 is 2, the two L 1 groups are identical to or different from each other,
L 2 is a ligand represented by Formula 4D,
n2 is 1 or 2, wherein, when n2 is 2 the two L 2 groups are identical to or different from each other, and
L 1 and L 2 are different from each other,
wherein, in Formulae 2 and 4D,
Y 1 and Y 3 are N,
Y 2 and Y 4 are C,
T 21 is a single bond,
ring CY 2 and ring CY 4 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,
ring CY 1 and ring CY 3 are each independently a C 1 -C 30 heterocyclic group, R 1 to R 4 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 1 -C 60 alkylthio group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 6 -C 60 aryloxy group, a substituted or unsubstituted C 6 -C 60 arylthio group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q 1 )(Q 2 ), —Si(Q 3 )(Q 4 )(Q 5 ), —Ge(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), —P(═O)(Q 8 )(Q 9 ), or —P(Q 8 )(Q 9 ),
a1 to a4 are each independently an integer from 0 to 20,
b1 and b2 are each independently an integer from 0 to 20, wherein the sum of b1 and b2 is 1 or greater,
Z 1 and Z 2 are each independently a group represented by Formula 3,
wherein, in Formula 3,
Q 51 and Q 52 are each independently hydrogen, deuterium, —F, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkylthio group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,
at least one of Q 51 and Q 52 in Formula 3 is each independently deuterium, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10 cycloalkenyl group, a substituted or unsubstituted C 1 -C 10 heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,
Q 53 is a substituted or unsubstituted C 6 -C 60 aryl group, a substituted or unsubstituted C 1 -C 60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,
two or more of a plurality of R 1 groups are optionally linked together to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,
two or more of a plurality of R 2 groups are optionally linked together to form a C 5 -C 30 carbocyclic group that is unsubstituted or substituted with at least one R 10a or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10a ,
R 10a is the same as described in connection with R 1 , * and *′ in Formulae 2 and 4D each indicate a binding site to M in Formula 1,
* in Formula 3 indicates a binding site to a neighboring atom,
in Formulae 2, 4D, and 3,
substituents of the substituted C 1 -C 60 alkyl group, the substituted C 2 -C 60 alkenyl group, the substituted C 2 -C 60 alkynyl group, the substituted C 1 -C 60 alkoxy group, the substituted C 1 -C 60 alkylthio group, the substituted C 3 -C 10 cycloalkyl group, the substituted C 1 -C 10 heterocycloalkyl group, the substituted C 3 -C 10 cycloalkenyl group, the substituted C 1 -C 10 heterocycloalkenyl group, the substituted C 6 -C 60 aryl group, the substituted C 6 -C 60 aryloxy group, the substituted C 6 -C 60 arylthio group, the substituted C 1 -C 60 heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group are each independently:
deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, or a C 2 -C 60 alkynyl group;
a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, or a C 2 -C 60 alkynyl group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 11 )(Q 12 ), —Si(Q 13 )(Q 14 )(Q 15 ), —Ge(Q 13 )(Q 14 )(Q 15 ), —B(Q 16 )(Q 17 ), —P(═O)(Q 18 )(Q 19 ), —P(Q 18 )(Q 19 ), or a combination thereof;
a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, a C 1 -C 60 alkoxy group, a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a C 3 -C 10 cycloalkenyl group, a C 1 -C 10 heterocycloalkenyl group, a C 6 -C 60 aryl group, a C 6 -C 60 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 21 )(Q 22 ), —Si(Q 23 )(Q 24 )(Q 25 ), —Ge(Q 23 )(Q 24 )(Q 25 ), —B(Q 26 )(Q 27 ), —P(═O)(Q 28 )(Q 29 ), —P(Q 28 )(Q 29 ), or a combination thereof;
—N(Q 31 )(Q 32 ), —Si(Q 33 )(Q 34 )(Q 35 ), —Ge(Q 33 )(Q 34 )(Q 35 ), —B(Q 36 )(Q 37 ), —P(═O)(Q 38 )(Q 39 ), or —P(Q 38 )(Q 39 );
or a combination thereof, and
Q 1 to Q 9 , Q 11 to Q 19 , Q 21 to Q 29 , and Q 31 to Q 39 are each independently: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a nitro group; an amidino group; a hydrazine group; a hydrazone group; a carboxylic acid group or a salt thereof; a sulfonic acid group or a salt thereof; a phosphoric acid group or a salt thereof; a C 1 -C 60 alkyl group unsubstituted or substituted with deuterium, —F, a C 1 -C 60 alkyl group, a C 6 -C 60 aryl group, a deuterated C 6 -C 60 aryl group, a fluorinated C 6 -C 60 aryl group, or a combination thereof; a C 2 -C 60 alkenyl group; a C 2 -C 60 alkynyl group; a C 1 -C 60 alkoxy group; a C 3 -C 10 cycloalkyl group; a C 1 -C 10 heterocycloalkyl group; a C 3 -C 10 cycloalkenyl group; a C 1 -C 10 heterocycloalkenyl group; a C 6 -C 60 aryl group or a C 1 -C 60 heteroaryl group, each unsubstituted or substituted with deuterium, —F, a C 1 -C 60 alkyl group, a deuterated C 1 -C 60 alkyl group, a fluorinated C 1 -C 60 alkyl group, a C 6 -C 60 aryl group, a deuterated C 6 -C 60 aryl group, a fluorinated C 6 -C 60 aryl group, or a combination thereof; a C 6 -C 60 aryloxy group; a C 6 -C 60 arylthio group; a monovalent non-aromatic condensed polycyclic group; or a monovalent non-aromatic condensed heteropolycyclic group.
2. The organometallic compound of claim 1 , wherein
ring CY 1 in Formula 2 is a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a benzoquinoline group, a benzoisoquinoline group, a benzoquinoxaline group, a benzoquinazoline group, a phenanthroline group, a phenanthridine group, a 5,6,7,8-tetrahydroisoquinoline group, a 5,6,7,8-tetrahydroquinoline group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, or an azadibenzosilole group.
3. The organometallic compound of claim 1 , wherein
ring CY 2 in Formula 2 is a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, or a group represented by Formula 2B:
wherein, in Formula 2B,
X 2 is O, S, Se, or a moiety comprising N, C, or Si,
ring 2B-1 and ring 2B-2 are each independently a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a benzoquinoline group, a benzoisoquinoline group, a benzoquinoxaline group, a benzoquinazoline group, a phenanthroline group, a phenanthridine group, a 5,6,7,8-tetrahydroisoquinoline group, a 5,6,7,8-tetrahydroquinoline group, an indene group, an indole group, a benzofuran group, a benzothiophene group, a benzosilole group, a fluorene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzosilole group, an azaindene group, an azaindole group, an azabenzofuran group, an azabenzothiophene group, an azabenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, or an azadibenzosilole group.
4. The organometallic compound of claim 1 , wherein
R 1 to R 4 in Formulae 2 and 4D are each independently:
hydrogen, deuterium, or —F;
a C 1 -C 20 alkyl group unsubstituted or substituted with deuterium, —F, a C 3 -C 10 cycloalkyl group, a deuterated C 3 -C 10 cycloalkyl group, a fluorinated C 3 -C 10 cycloalkyl group, a (C 1 -C 20 alkyl)C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a deuterated C 1 -C 10 heterocycloalkyl group, a fluorinated C 1 -C 10 heterocycloalkyl group, a (C 1 -C 20 alkyl)C 1 -C 10 heterocycloalkyl group, or a combination thereof;
a C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a phenyl group, a biphenyl group, a naphthyl group, or a pyridinyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C 1 -C 20 alkyl group, a deuterated C 1 -C 20 alkyl group, a fluorinated C 1 -C 20 alkyl group, a C 3 -C 10 cycloalkyl group, a deuterated C 3 -C 10 cycloalkyl group, a fluorinated C 3 -C 10 cycloalkyl group, a (C 1 -C 20 alkyl)C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a deuterated C 1 -C 10 heterocycloalkyl group, a fluorinated C 1 -C 10 heterocycloalkyl group, a (C 1 -C 20 alkyl)C 1 -C 10 heterocycloalkyl group, a phenyl group, a deuterated phenyl group, a fluorinated phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a fluorinated biphenyl group, a (C 1 -C 20 alkyl) biphenyl group, a naphthyl group, a deuterated naphthyl group, a fluorinated naphthyl group, a (C 1 -C 20 alkyl) naphthyl group, a pyridinyl group, a deuterated pyridinyl group, a fluorinated pyridinyl group, a (C 1 -C 20 alkyl)pyridinyl group, or a combination thereof; or
—Si(Q 3 )(Q 4 )(Q 5 ) or —Ge(Q 3 )(Q 4 )(Q 5 ),
wherein,
Q 3 to Q 5 are each independently:
deuterium;
a C 1 -C 60 alkyl group unsubstituted or substituted with deuterium, —F, a C 1 -C 60 alkyl group, a C 6 -C 60 aryl group, a deuterated C 6 -C 60 aryl group, a fluorinated C 6 -C 60 aryl group, or a combination thereof, or
a C 6 -C 60 aryl group or a C 1 -C 60 heteroaryl group, each unsubstituted or substituted with deuterium, —F, a C 1 -C 60 alkyl group, a deuterated C 1 -C 60 alkyl group, a fluorinated C 1 -C 60 alkyl group, a C 6 -Coo aryl group, a deuterated C 6 -C 60 aryl group, a fluorinated C 6 -C 60 aryl group, or a combination thereof.
5. The organometallic compound of claim 1 , wherein
at least one R 1 in the number of a1 in Formula 2 is: deuterium; —F; a C 1 -C 20 alkyl group or a C 3 -C 10 cycloalkyl group, each unsubstituted or substituted with deuterium, —F, C 1 -C 10 alkyl group, or a combination thereof; a group represented by —Si(Q 3 )(Q 4 )(Q 5 ); or a group represented by —Ge(Q 3 )(Q 4 )(Q 5 ).
6. The organometallic compound of claim 1 , wherein
i) b1 is 1 or 2, and b2 is 0;
ii) b1 is 0, and b2 is 1 or 2; or
iii) b1 and b2 are each 1.
7. The organometallic compound of claim 1 , wherein
at least one of Q 51 and Q 52 in Formula 3 is each independently:
deuterium; or a C 1 -C 20 alkyl group unsubstituted or substituted with deuterium, —F, or a combination thereof.
8. The organometallic compound of claim 1 , wherein Q 53 in Formula 3 is a phenyl group, a biphenyl group, a naphthyl group, or a pyridinyl group, each unsubstituted or substituted with deuterium, —F, a C 1 -C 20 alkyl group, a deuterated C 1 -C 20 alkyl group, a fluorinated C 1 -C 20 alkyl group, a C 3 -C 10 cycloalkyl group, a deuterated C 3 -C 10 cycloalkyl group, a fluorinated C 3 -C 10 cycloalkyl group, a (C 1 -C 20 alkyl)C 3 -C 10 cycloalkyl group, a C 1 -C 10 heterocycloalkyl group, a deuterated C 1 -C 10 heterocycloalkyl group, a fluorinated C 1 -C 10 heterocycloalkyl group, a (C 1 -C 20 alkyl)C 1 -C 10 heterocycloalkyl group, a phenyl group, a deuterated phenyl group, a fluorinated phenyl group, a (C 1 -C 20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a fluorinated biphenyl group, a (C 1 -C 20 alkyl) biphenyl group, a naphthyl group, a deuterated naphthyl group, a fluorinated naphthyl group, a (C 1 -C 20 alkyl) naphthyl group, a pyridinyl group, a deuterated pyridinyl group, a fluorinated pyridinyl group, a (C 1 -C 20 alkyl)pyridinyl group, or a combination thereof.
9. The organometallic compound of claim 1 , wherein in Formula 2, a group represented by
is a group represented by one of Formulae CY1(1) to CY1(16) and CY1(1)Z to CY1(38)Z:
wherein, in Formulae CY1(1) to CY1(16) and CY1(1) Z to CY1(38) Z,
Y 1 is the same as described in claim 1 ,
R 11 to R 14 are each the same as described in connection with R 1 in claim 1 , provided that each of R 11 to R 14 is not hydrogen,
Z 11 to Z 14 are each the same as described in connection with Z 1 in claim 1 ,
*′ indicates a binding site to M in Formula 1, and
*″ indicates a binding site to ring CY 2 in Formula 2.
10. The organometallic compound of claim 1 , wherein in Formula 2, a group represented by
is a group represented by one of Formulae CY2(1) to CY2(96) and CY2(1)Z to CY2(54)Z:
wherein, in Formulae CY2(1) to CY2(96) and CY2(1)Z to CY2(54)Z,
Y 2 is the same as described in claim 1 ,
X 22 is C(R 29a )(R 29b ), N(R 29a ), O, S, Se, or Si(R 29a )(R 29b ),
R 21 to R 28 , R 29a , and R 29b are each the same as described in connection with R 2 in claim 1 , provided that each of R 21 to R 28 is not hydrogen,
Z 21 to Z 28 are each the same as described in connection with Z 2 in claim 1 ,
* indicates a binding site to M in Formula 1, and
*″ indicates a binding site to ring CY 1 in Formula 2.
11. The organometallic compound of claim 1 , wherein in Formula 4D, a group represented by
is a group represented by one of Formulae CY3(1) to CY3(16):
wherein, in Formulae CY3(1) to CY3(16),
Y 3 is the same as described in claim 1 ,
R 31 to R 34 are each the same as described in connection with R 3 in claim 1 , provided that each of R 31 to R 34 is not hydrogen,
* indicates a binding site to M in Formula 1, and
*″ indicates a binding site to T 21 in Formula 4D.
12. The organometallic compound of claim 1 , wherein in Formula 4D, a group represented by
is a group represented by one of Formulae CY4(1) to CY4(96):
wherein, in Formulae CY4(1) to CY4(96),
Y 4 is the same as described in claim 1 ,
X 42 is C(R 49a )(R 49b ), N(R 49a ), O, S, Se, or Si(R 49a )(R 49b ),
R 41 to R 48 , R 49a , and R 49b are each the same as described in connection with R 4 in claim 1 , provided that each of R 41 to R 48 is not hydrogen,
*′ indicates a binding site to M in Formula 1, and
*″ indicates a binding site to a binding site to T 21 in Formula 4D.
13. An organic light-emitting device, comprising:
a first electrode;
a second electrode; and
an organic layer disposed between the first electrode and the second electrode and comprising an emission layer,
wherein the organic layer comprises at least one organometallic compound of claim 1 .
14. The organic light-emitting device of claim 13 , wherein
the first electrode is an anode,
the second electrode is a cathode,
the organic layer further comprises a hole transport region disposed between the first electrode and the emission layer, and an electron transport region disposed between the emission layer and the second electrode,
the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or a combination thereof, and
the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or a combination thereof.
15. The organic light-emitting device of claim 13 , wherein
the emission layer comprises the at least one organometallic compound.
16. The organic light-emitting device of claim 15 , wherein
the at least one organometallic compound emits green light.
17. The organic light-emitting device of claim 15 , wherein
the emission layer further comprises a host, and an amount of the host in the emission layer is greater than an amount of the at least one organometallic compound in the emission layer, based on weight.
18. An electronic apparatus, comprising the organic light-emitting device of claim 13 .
19. The organometallic compound of claim 1 ,
wherein a1 is not zero and at least one R 1 in the number of a1 in Formula 2 is: deuterium; —F; a C 1 -C 20 alkyl group unsubstituted or substituted with deuterium, —F, C 1 -C 10 alkyl group, or a combination thereof, or a group represented by —Si(Q 3 )(Q 4 )(Q 5 ) or Ge(Q 3 )(Q 4 )(Q 5 );
wherein ring CY 2 in Formula 2 is a 1,2,3,4-tetrahydronaphthalene group or a group represented by Formula 2B:
wherein, in Formula 2B,
X 2 is O, S, Se, or a moiety comprising N, C, or Si,
ring 2B-1 and ring 2B-2 are each independently a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a benzoquinoline group, a benzoisoquinoline group, a benzoquinoxaline group, a benzoquinazoline group, a phenanthroline group, a phenanthridine group, a 5,6,7,8-tetrahydroisoquinoline group, a 5,6,7,8-tetrahydroquinoline group, an indene group, an indole group, a benzofuran group, a benzothiophene group, a benzosilole group, a fluorene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzosilole group, an azaindene group, an azaindole group, an azabenzofuran group, an azabenzothiophene group, an azabenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, or an azadibenzosilole group
wherein in Formula 4D, a group represented by
is a group represented by one of Formulae CY4(18) to CY4(96):
wherein, in Formulae CY4(18) to CY4(96),
X 42 is C(R 49a )(R 49b ), N(R 49a ), O, S, Se, or Si(R 49a )(R 49b ),
R 41 to R 48 , R 49a , and R 49b are each the same as described in connection with R 4 in claim 1 ,
provided that each of R 41 to R 48 is not hydrogen,
*′ indicates a binding site to M in Formula 1, and
*″ indicates a binding site to a binding site to T 21 in Formula 4D.
20. The organometallic compound of claim 19 , wherein
at least one of Q 51 and Q 52 in Formula 3 is each independently:
deuterium; or a C 1 -C 20 alkyl group unsubstituted or substituted with deuterium, —F, or a combination thereof.