Organometallic compound, organic light-emitting device including the same, and electronic apparatus including the organic light-emitting device

1. An organometallic compound represented by Formula 1:

wherein, in Formula 1,

M is a transition metal,

X 1 to X 4 in Formula 1 are each independently C or N,

X 5 in Formula 1 is O, S, N(R′), or C(R′)(R″),

wherein,

a bond between X 5 and M in Formula 1 is a covalent bond, and

one of a bond between X 2 and M in Formula 1, a bond between X 3 and M in Formula 1, and a bond between X 4 and M in Formula 1 is a covalent bond, and the other two are each a coordinate bond,

ring CY 1 to ring CY 4 in Formula 1 are each independently a C 5 -C 30 carbocyclic group or a C 1 -C 30 heterocyclic group,

T 1 to T 4 in Formula 1 are each independently a single bond, a double bond, *—N(R 5a )—*′, *—B(R 5a )—*′, *—P(R 5a )—*′, *—C(R 5a )(R 5b )—*′, *—Si(R 5a )(R 5b )—*′, *—Ge(R 5a )(R 5b )—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O) 2 —*′, *—C(R 5a )═*′, *═C(R 5a )—*′, *—C(R 5a )—C(R 5b )—*′, *—C(═S)—*′, *—C═C—*′, 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 ,

each of n1 and n2 in Formula 1 is 1,

n3 and n4 in Formula 1 are each independently 0 or 1, wherein at least three of n1 to n4 are each 1,

when n3 in Formula 1 is 0, T 3 is not present, and when n4 in Formula 1 is 0, T 4 is not present,

Z 1 to Z 4 in Formula 1 are each independently a group represented by Formula 51,

d1 to d4 in Formula 1 are each independently an integer from 0 to 20,

L 1 to L 4 and L 51 in Formulae 1 and 51 are each independently a single bond, 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 ,

b1 to b4 and b51 in Formulae 1 and 51 are each independently an integer from 1 to 10,

R 1 to R 4 , R 5a , R 5b , R′, R″, and Q 51 to Q 53 in Formulae 1 and 51 each independently a group represented by Formula 51, hydrogen, deuterium, —F, —Cl, —Br, —I, —SF 5 , a hydroxyl group, a cyano 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 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 7 -C 60 alkyl aryl group, a substituted or unsubstituted C 7 -C 60 aryl alkyl 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 C 2 -C 60 alkyl heteroaryl group, a substituted or unsubstituted C 2 -C 60 heteroaryl alkyl group, a substituted or unsubstituted C 1 -C 60 heteroaryloxy group, a substituted or unsubstituted C 1 -C 60 heteroarylthio 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 ),

provided that none of Q 51 to Q 53 is a group represented by Formula 51,

at least one of Q 51 to Q 53 in Formula 51 is independently 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,

c1 to c4 and a1 to a4 in Formula 1 are each independently an integer from 0 to 20,

c51 in Formula 51 is an integer from 1 to 20,

Formula 1 satisfies at least one of Condition 1 and Condition 2,

Condition 1

a sum of d1 to d4 in Formula 1 is 1 or more,

Condition 2

at least one of T 1 to T 4 in Formula 1 is *—N(R 5a )—*′, *—B(R 5a )—*′, *—P(R 5a )—*′, *—C(R 5a )(R 5b )—*′, *—Si(R 5a )(R 5b )—*′, *—Ge(R 5a )(R 5b )—*′, *—C(R 5a )═*′, *═C(R 5a )—*′, or *—C(R 5a )═C(R 5b )—*′, and

at least one of R 5a and R 5b is a group represented by Formula 51,

provided that, when i) ring CY 2 is a benzimidazole group, ii) d1, d3 and d4 are 0, and iii) d2 is 1 or more, then each Z 2 is independently a group represented by Formula 51, wherein each L 51 is independently a single bond, a monocyclic C 5 -C 8 carbocyclic group that is unsubstituted or substituted with at least one R 10b , or a C 1 -C 30 heterocyclic group that is unsubstituted or substituted with at least one R 10b , and the R 10b is i) deuterium; ii) —F; iii) a cyano group; or iv) a C 1 -C 20 alkyl group that is unsubstituted or substituted with deuterium, —F, a cyano group, or a combination thereof,

two or more of a plurality of R 1 (s) in Formula 1 are optionally bonded 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 (s) in Formula 1 are optionally bonded 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 3 (s) in Formula 1 are optionally bonded 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 4 (s) in Formula 1 are optionally bonded 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 R 1 to R 4 , R 5a and one or more of R 1 to R 4 , Rob and one or more of R 1 to R 4 , or R 5a and R 5b are each optionally bonded 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 defined in connection with R 1 ,

* and *′ each indicate a binding site to a neighboring atom, and

the substituent 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 7 -C 60 alkyl aryl group, the substituted C 7 -C 60 aryl alkyl 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 C 2 -C 60 alkyl heteroaryl group, the substituted C 2 -C 60 heteroaryl alkyl group, the substituted C 1 -C 60 heteroaryloxy group, the substituted C 1 -C 60 heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is:

deuterium, —F, —Cl, —Br, —I, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a hydroxyl group, a cyano 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 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, or a C 1 -C 60 alkylthio group;

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, or a C 1 -C 60 alkylthio 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 cyano 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 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 C 2 -C 60 heteroaryl alkyl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio 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 aryloxy group, a C 6 -C 60 arylthio group, a C 1 -C 60 heteroaryl group, a C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio 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 cyano 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 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 1 -C 60 alkylthio 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 C 1 -C 60 heteroaryloxy group, a C 1 -C 60 heteroarylthio 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,

wherein 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 cyano 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 which is unsubstituted or substituted with deuterium, a C 1 -C 60 alkyl group, a 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 1 -C 60 alkylthio 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 which is unsubstituted or substituted with deuterium, a C 1 -C 60 alkyl group, a 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 C 1 -C 60 heteroaryl group; a C 1 -C 60 heteroaryloxy group; a C 1 -C 60 heteroarylthio group; a monovalent non-aromatic condensed polycyclic group; or a monovalent non-aromatic condensed heteropolycyclic group, and

wherein a group represented by

is a group represented by one of Formulae CY2-1 to CY2-16 or ZCY2-1 to ZCY2-19:

wherein, in Formulae CY2-1 to CY2-16 and ZCY2-1 to ZCY2-19,

X 29 is O, S, N-[(L 2 ) b2 -(R 2 ) c2 ], C(R 29a )(R 29b ), or Si(R 29a )(R 29b ),

Z 21 to Z 24 are each independently as defined in connection with Z 2 ,

R 21 to R 23 , R 29a , and R 29 are each independently as defined in connection with R 2 , provided that each of R 21 to R 23 is not hydrogen, and

*′ indicates a binding site to T 1 in Formula 1, * indicates a binding site to M in Formula 1, and *″ indicates a binding site to T 2 in Formula 1.

2. The organometallic compound of claim 1 , wherein M in Formula 1 is Pt, Pd, or Au.

3. The organometallic compound of claim 1 , wherein

X 2 is N, and

ring CY 2 is a pyridine group.

4. The organometallic compound of claim 1 ,

wherein T 1 and T 2 in Formula 1 are each a single bond, and

T 3 in Formula 1 is a single bond, *—N(R 5a )—*′, *—B(R 5a )—*′, *—P(R 5a )—*′, *—C(R 5a )(R 5b )—*′, *—Si(R 5a )(R 5b )—*′, *—Ge(R 5a )(R 5b )—*′, *—S—*′, or *—O—*′.

5. The organometallic compound of claim 1 , wherein

n1 to n3 in Formula 1 are each 1, and

n4 in Formula 1 is 0.

6. The organometallic compound of claim 1 , wherein the organometallic compound satisfies at least one of Condition 1A and Condition 2A:

Condition 1A

in Formula 1,

i) d1 is 1, and each of d2, d3, and d4 is 0;

ii) d2 is 1, and each of d1, d3, and d4 is 0;

iii) d3 is 1, and each of d1, d2, and d4 is 0;

iv) d4 is 1, and each of d1, d2, and d3 is 0;

v) each of d1 and d2 is 1, and each of d3 and d4 is 0;

vi) each of d2 and d3 is 1, and each of d1 and d4 is 0; or

vii) each of d2 and d4 is 1, and each of d1 and d3 is 0,

Condition 2A

in Formula 1, n3 is 1, and

i) T 3 is *—N(R 5a )—*′, *—B(R 5a )—*′, *—P(R 5a )—*′, *—C(R 5a )═*′, or *═C(R 5a )—*′, wherein R 5a is a group represented by Formula 51; or

ii) T 3 is *—C(R 5a )(R 5b )—*′, *—Si(R 5a )(R 5b )—*′, *—Ge(R 5a )(R 5b )—*′, or *—C(R 5a )═C(R 5b )—*′, wherein at least one of R 5a and R 5b is a group represented by Formula 51.

7. The organometallic compound of claim 1 , wherein a group represented by *—C(Q 51 )(Q 52 )(Q 53 ) in Formula 51 is a group represented by one of Formulae 51-1 to 51-25:

wherein,

Q 51 and Q 52 in Formulae 51-1 to 51-25 are as defined in claim 1 ,

Q 61 to Q 66 in Formulae 51-1 to 51-25 are each independently as defined in connection with R 10a in claim 1 , provided that none of Q 61 to Q 65 in Formulae 51-1 to 51-25 is hydrogen, and

* in Formulae 51-1 to 51-25 indicates a binding site to L 51 in Formula 51.

8. The organometallic compound of claim 1 , wherein L 51 in Formula 51 is a single bond.

9. The organometallic compound of claim 1 , wherein a group represented by Formula 51 is a group represented by one of Formulae 51(1) to 51(19):

wherein,

T 11 to T 15 in Formulae 51(1) to 51(19) are each a group represented by *—C(Q 51 )(Q 52 )(Q 53 ) in Formula 51,

T 11 to T 15 in Formulae 51( 1 ) to 51(19) are identical to or different from each other,

R 10a in Formulae 51(1) to 51(19) is as defined in connection with R 1 in claim 1 , and

* in Formulae 51(1) to 51(19) indicates a binding site to a neighboring atom.

10. The organometallic compound of claim 1 , wherein, in Formula 1,

n4 is 0, and

a group represented by

is a group represented by one of Formulae CY1-1 to CY1-18 or ZCY1-1 to ZCY1-32:

wherein, in Formulae CY1-1 to CY1-18 and ZCY1-1 to ZCY1-32,

X 1 is as defined in claim 1 ,

R 11 to R 14 are each independently as defined 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 independently as defined in connection with Z 1 in claim 1 ,

* indicates a binding site to X 5 in Formula 1, and

*′ indicates a binding site to T 1 in Formula 1.

11. The organometallic compound of claim 1 , wherein, in Formula 1,

each of n2 and n3 is 1, and

a group represented by

is a group represented by one of Formulae CY3-1 to CY3-13 or ZCY3-1 to ZCY3-12:

wherein, in Formulae CY3-1 to CY3-13 and ZCY3-1 to ZCY3-12,

X 3 is as defined in claim 1 ,

X 39 is O, S, N-[(L 3 ) b3 -(R 3 ) c3 ], C(R 39a )(R 39b ), or Si(R 39a )(R 39b ),

L 3 , b3, R 3 , and c3 are each independently as defined in claim 1 ,

R 31 to R 33 , R 39a , and R 39b are each independently as defined in connection with R 3 in claim 1 , provided that each of R 31 to R 33 is not hydrogen,

Z 31 to Z 33 are each independently as defined in connection with Z 3 in claim 1 ,

*″ indicates a binding site to T 2 in Formula 1,

*indicates a binding site to M in Formula 1, and

*′ indicates a binding site to T 3 in Formula 1.

12. The organometallic compound of claim 1 , wherein, in Formula 1,

n3 is 1 and n4 is 0, and

a group represented by

is a group represented by one of Formulae CY4-1 to CY4-16 or ZCY4-1 to ZCY4-32:

wherein, in Formulae CY4-1 to CY4-16 and ZCY4-1 to ZCY4-32,

X 4 is as defined in claim 1 ,

R 41 to R 44 are each independently as defined in connection with R 4 in claim 1 , provided that each of R 41 to R 44 is not hydrogen,

Z 41 to Z 44 are each independently as defined in connection with Z 4 in claim 1 ,

*′ indicates a binding site to T 3 in Formula 1, and

*is a binding site to M in Formula 1.

13. The organometallic compound of claim 1 , wherein the organometallic compound is represented by one of Formulae 1-1 to 1-4:

wherein, in Formulae 1-1 to 1-4,

M, X 1 to X 5 , T 2 , and T 3 are each independently as defined in claim 1 ,

X 11 is N, C(R 11 ), or C(Z 11 ), X 12 is N, C(R 12 ), or C(Z 12 ), X 13 is N, C(R 13 ), or C(Z 13 ), and X 14 is N, C(R 14 ), or C(Z 14 ),

R 11 to R 14 are each independently as defined in connection with R 1 in claim 1 ,

Z 11 to Z 14 are each independently as defined in connection with Z 1 in claim 1 ,

two or more of R 11 to R 14 are optionally bonded 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 ,

X 21 is N, C(R 21 ), or C(Z 21 ),

X 22 is N, C(R 22 ), or C(Z 22 ),

X 23 is N, C(R 23 ), or C(Z 23 ),

X 29 is O, S, N—[(L 2 ) b2 -(R 2 ) c2 ], C(R 29a )(R 29b ), or Si(R 29a )(R 29b ),

L 2 , b2, R 2 , and c2 are each independently as defined in claim 1 ,

R 21 to R 23 , R 29a , and R 29b are each independently as defined in connection with R 2 in claim 1 ,

Z 21 to Z 24 are each independently as defined in connection with Z 2 in claim 1 ,

two or more of R 21 to R 23 are optionally bonded 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 ,

X 31 is N, C(R 31 ), or C(Z 31 ),

X 32 is N, C(R 32 ), or C(Z 32 ),

X 33 is N, C(R 33 ), or C(Z 33 ),

R 31 to R 33 are each independently as defined in connection with R 3 in claim 1 ,

Z 31 to Z 33 are each independently as defined in connection with Z 3 in claim 1 ,

two or more of R 31 to R 33 are optionally bonded 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 ,

X 41 is N, C(R 41 ), or C(Z 41 ),

X 42 is N, C(R 42 ), or C(Z 42 ),

X 43 is N, C(R 43 ), or C(Z 43 ),

X 44 is N, C(R 44 ), or C(Z 44 ),

R 41 to R 44 are each independently as defined in connection with R 4 in claim 1 ,

Z 41 to Z 44 are each independently as defined in connection with Z 4 in claim 1 ,

two or more of R 41 to R 44 are optionally bonded 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 ,

wherein Formulae 1-1 and 1-2 each include one of Z 11 to Z 14 , one of Z 21 to Z 23 , one of Z 31 to Z 33 , one of Z 41 to Z 44 , or a combination thereof, and

R 5a in Formula 1-4 is a group represented by Formula 51.

14. The organometallic compound of claim 13 , wherein

i) the organometallic compound is represented by Formula 1-1 or 1-2, and Formulae 1-1 and 1-2 each satisfy at least one of Condition (1′) to Condition (3′);

ii) the organometallic compound is represented by Formula 1-3 or 1-4; or

iii) the organometallic compound is represented by Formula 1-3 or 1-4, and Formulae 1-3 and 1-4 each satisfy at least one of Condition (1′) to Condition (3′):

Condition (1′)

X 22 is C(Z 22 )

Condition (2′)

X 32 is C(Z 32 )

Condition (3′)

X 43 is C(Z 43 ),

wherein,

Z 22 , Z 32 , and Z 43 are each independently as defined in claim 13 .

15. An organic light-emitting device, comprising:

a first electrode;

a second electrode; and

an organic layer located between the first electrode and the second electrode,

wherein the organic layer comprises an emission layer, and

wherein the organic layer comprises the at least one organometallic compound of claim 1 .

16. The organic light-emitting device of claim 15 , wherein

the first electrode is an anode,

the second electrode is a cathode,

the organic layer further comprises a hole transport region located between the first electrode and the emission layer, and an electron transport region located 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, 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.

17. The organic light-emitting device of claim 15 , wherein the at least one organometallic compound is included in the emission layer.

18. The organic light-emitting device of claim 17 , wherein

the emission layer further comprises a host, and

an amount of the host is greater than an amount of the at least one organometallic compound in the emission layer.

19. An electronic apparatus, comprising the organic light-emitting device of claim 15 .