Organometallic compound, organic light-emitting device including the organometallic compound, and diagnosis composition including the organometallic compound

1. An organometallic compound represented by Formula 1:

wherein, in Formula 1,

M is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au),

X 1 is N and a bond between X 1 and M is a covalent bond,

X 2 to X 4 are each independently N or C; at least one of X 2 to X 4 is C; one bond selected from a bond between X 2 and M, a bond between X 3 and M, and a bond between X 4 and M is a covalent bond; and each of the remaining two bonds is a coordinate bond,

Y 1 to Y 9 are each independently C or N,

a bond between Y 1 and Y 2 , a bond between Y 1 and Y 3 , a bond between X 2 and Y 4 , a bond between X 2 and Y 5 , a bond between X 3 and Y 6 , a bond between X 3 and Y 7 , a bond between X 4 and Y 8 , a bond between X 4 and Y 9 , a bond between Y 2 and X 52 , and a bond between X 51 and X 52 are each independently a single bond or a double bond,

CY 1 to CY 5 are each independently selected from a C 5 -C 30 carbocyclic group and a C 1 -C 30 heterocyclic group,

a cyclometallated ring formed by CY 5 , CY 1 , CY 2 , and M is a 6-membered ring, a 7-membered ring, or an 8-membered ring,

T 1 to T 3 are each independently selected from *—O—*′, *—S—*′, *—C(R 5 )(R 6 )—*′, *—C(R 5 )=*′, *═C(R 5 )—*′, *—C(R 5 )═C(R 6 )—*′, *—C(═O)—*′, *—C(═S)—′, *—C≡C—*′, *—N(R 5 )—*′, *—Si(R 5 )(R 6 )—*′, and *—P(R 5 )(R 6 )—*′,

R 5 and R 6 are optionally linked via a first linking group to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

b1 to b3 are each independently 0, 1, 2, or 3, wherein when b1 is zero, *-(T 1 ) b1 -*′ is a single bond, when b2 is zero, *-(T 2 ) b2 -*′ is a single bond, and when b3 is zero, *-(T 3 ) b3 -*′ is a single bond,

X 51 is selected from O, S, N, N(R 51 ), C(R 51 ), C(R 51 )(R 52 ), Si(R 51 )(R 52 ), and C(═O),

X 52 is selected from O, S, N, N(R 53 ), C(R 53 ), C(R 53 )(R 54 ), Si(R 53 )(R 54 ), and C(═O),

R 51 and R 52 are optionally linked via a second linking group to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 53 and R 54 are optionally linked via a third linking group to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 51 and R 53 are optionally linked via a fourth linking group to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 1 to R 6 and R 51 to R 54 are each independently selected from 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 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 6 ), —B(Q 6 )(Q 7 ), and —P(═O)(Q 8 )(Q 9 ),

a1 to a4 are each independently 0, 1, 2, 3, 4, or 5,

two of groups R 1 in the number of a1 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

two of groups R 2 in the number of a2 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

two of R 3 in the number of a3 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

two of groups R 4 in the number of a4 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

two or more neighboring groups selected from R 1 to R 4 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

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

at least one substituent of the substituted C 5 -C 30 carbocyclic group, the substituted C 1 -C 30 heterocyclic group, 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 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 is selected from:

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 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, and a C 1 -C 60 alkoxy group;

a C 1 -C 60 alkyl group, a C 2 -C 60 alkenyl group, a C 2 -C 60 alkynyl group, and a C 1 -C 60 alkoxy group, each substituted with at least one selected from 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 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 ), —B(Q 16 )(Q 17 ), and —P(═O)(Q 18 )(Q 19 );

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, and a monovalent non-aromatic condensed heteropolycyclic 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, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from 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 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 ), —B(Q 26 )(Q 27 ), and —P(═O)(Q 28 )(Q 29 ); and

—N(Q 31 )(Q 32 ), —Si(Q 33 )(Q 34 )(Q 35 ), —B(Q 36 )(Q 37 ), and —P(═O)(Q 38 )(Q 39 ),

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 selected from 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, 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 aryl group substituted with at least one of a C 1 -C 60 alkyl group and 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, and a monovalent non-aromatic condensed heteropolycyclic group.

2. The organometallic compound of claim 1 , wherein

CY 1 to CY 4 are each independently selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole 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 phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline.

3. The organometallic compound of claim 1 , wherein

a moiety represented by

in Formula 1 is a group represented by Formula CY1-1:

wherein, in Formula CY1-1,

X 51 and X 52 are the same as described in claim 1 ,

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

R 11 to R 13 are each independently the same as described in connection with R 1 in claim 1 , and

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

4. The organometallic compound of claim 1 , wherein

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY2-1 to CY2-6:

wherein, in Formulae CY2-1 to CY2-4,

X 21 is N or C(R 21 ), X 22 is N or C(R 22 ), X 23 is N or C(R 23 ), X 24 is N or C(R 24 ), X 25 is N or C(R 25 ), X 26 is N or C(R 26 ), and X 27 is N or C(R 27 ),

R 21 to R 27 are each independently the same as described in connection with R 2 in claim 1 , and

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

5. The organometallic compound of claim 1 , wherein

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY3-1 to CY3-22:

wherein, in Formulae CY3-1 to CY3-22,

X 31 is N or C(R 31 ), X 32 is N or C(R 32 ), X 33 is N or C(R 33 ), X 34 is N or C(R 34 ), X 35 is N or C(R 35 ), X 36 is N or C(R 36 ), X 37 is N or C(R 37 ), and X 38 is N or C(R 38 ),

X 39 is C(R 39a )(R 39b ) N(R 39 ), O, S, or Si(R 39a )(R 39b ),

R 31 to R 39 , R 39a , and R 39b are each independently the same as described in connection with R 3 in claim 1 , and

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

6. The organometallic compound of claim 1 , wherein

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY4-1 to CY4-8:

wherein, in Formulae CY4-1 to CY4-8,

X 41 is N or C(R 41 ), X 42 is N or C(R 42 ), X 43 is N or C(R 43 ), X 44 is N or C(R 44 ), X 45 is N or C(R 45 ), X 46 is N or C(R 46 ), X 47 is N or C(R 47 ), and X 48 is N or C(R 48 ),

R 41 to R 48 are each independently the same as described in connection with R 4 in claim 1 , and

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

7. The organometallic compound of claim 1 , wherein

T 1 to T 3 are each independently selected from *—O—*′, *—S—*′, *—C(R 5 )(R 6 )—*′, *—N(R 5 )—*′, *—Si(R 5 )(R 6 )—*′, and *—P(R 5 )(R 6 )—*′.

8. The organometallic compound of claim 1 , wherein

T 1 to T 3 are each independently selected from *—C(R 5 )(R 6 )—*′, *—Si(R 5 )(R 6 )—*′, and *—P(R 5 )(R 6 )—*′,

R 5 and R 6 are linked via a first linking group, and

the first linking group is selected from a single bond, *—O—*′, *—S—*′, *—C(R 9 )(R 10 )—*′, *—C(R 9 )=*′, *═C(R 9 )—*′, *—C(R 9 )═C(R 10 )—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—N(R 9 )—*′, *—Si(R 9 )(R 10 )—*′, and *—P(R 9 )(R 10 )—*′, wherein R 9 and R 10 are the same as described in connection with R 5 in claim 1 , and * and *′ each indicate a binding site to a neighboring atom.

9. The organometallic compound of claim 1 , wherein

b1 is 1 and b2 and b3 are each zero;

b2 is 1 and b1 and b3 are each zero; or

b3 is 1 and b1 and b2 are each zero.

10. The organometallic compound of claim 1 , wherein

R 1 to R 6 and R 51 to R 54 are each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, 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, —SF 5 , a C 1 -C 20 alkyl group, and a C 1 -C 20 alkoxy group;

a C 1 -C 20 alkyl group and a C 1 -C 20 alkoxy group, each substituted with at least one selected from 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 10 alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from 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 20 alkyl group, a C 1 -C 20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; and

—N(Q 1 )(Q 2 ), —Si(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), and —P(═O)(Q 8 )(Q 9 ),

wherein Q 1 to Q 9 are each independently selected from:

—CH 3 , —CD 3 , —CD 2 H, —CDH 2 , —CH 2 CH 3 , —CH 2 CD 3 , —CH 2 CD 2 H, —CH 2 CDH 2 , —CHDCH 3 , —CHDCD 2 H, —CHDCDH 2 , —CHDCD 3 , —CD 2 CD 3 , —CD 2 CD 2 H, and —CD 2 CDH 2 ;

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C 1 -C 10 alkyl group, and a phenyl group.

11. The organometallic compound of claim 1 , wherein

R 1 to R 6 and R 51 to R 54 are each independently selected from:

hydrogen, deuterium, —F, a cyano group, a nitro group, —SF 5 , a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a quinolinyl group, an isoquinolinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group;

a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an iso-heptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an iso-octyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an iso-decyl group, a sec-decyl group, a tert-decyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a quinolinyl group, an isoquinolinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , a cyano group, a nitro group, a C 1 -C 10 alkyl group, a C 1 -C 10 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and

—N(Q 1 )(Q 2 ), —Si(Q 3 )(Q 4 )(Q 5 ), —B(Q 6 )(Q 7 ), and —P(═O)(Q 8 )(Q 9 ),

wherein Q 1 to Q 9 are each independently selected from:

—CH 3 , —CD 3 , —CD 2 H, —CDH 2 , —CH 2 CH 3 , —CH 2 CD 3 , —CH 2 CD 2 H, —CH 2 CDH 2 , —CHDCH 3 , —CHDCD 2 H, —CHDCDH 2 , —CHDCD 3 , —CD 2 CD 3 , —CD 2 CD 2 H, and —CD 2 CDH 2 ;

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C 1 -C 10 alkyl group, and a phenyl group.

12. The organometallic compound of claim 1 , wherein

R 1 to R 6 and R 51 to R 54 are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF 5 , —CH 3 , —CD 3 , —CD 2 H, —CDH 2 , —CF 3 , —CF 2 H, —CFH 2 , groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-48, and —Si(Q 3 )(Q 4 )(Q 5 ):

wherein * in Formulae 9-1 to 9-19 and 10-1 to 10-48 indicates a binding site to a neighboring atom.

13. The organometallic compound of claim 1 , wherein

the organometallic compound is represented by Formula 1-1:

wherein, in Formula 1-1,

M, T 1 to T 3 , b1 to b3, X 51 , and X 52 are the same as described in claim 1 ,

X 11 is N or C(R 11 ), X 12 is N or C(R 12 ), X 13 is N or C(R 13 ), X 21 is N or C(R 21 ), X 22 is N or C(R 22 ), X 23 is N or C(R 23 ), X 31 is N or C(R 31 ), X 32 is N or C(R 32 ), X 33 is N or C(R 33 ), X 41 is N or C(R 41 ), X 42 is N or C(R 42 ), X 43 is N or C(R 43 ), and X 44 is N or C(R 44 ),

R 11 to R 13 are each independently the same as described in connection with R 1 in claim 2 , and two of R 11 to R 13 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 21 to R 23 are each independently the same as described in connection with R 2 in claim 1 , and two of R 21 to R 23 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 31 to R 33 are each independently the same as described in connection with R 3 in claim 1 , and two of R 31 to R 33 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 41 to R 44 are each independently the same as described in connection with R 4 in claim 1 , and two of R 41 to R 44 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group, and

two of R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 44 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group.

14. The organometallic compound of claim 1 , wherein

the organometallic compound is represented by Formula 1-1A:

wherein, in Formula 1-1A,

M, T 1 , T 2 , b1, b2, X 51 , and X 52 are the same as described in claim 1 ,

X 11 is N or C(R 11 ), X 12 is N or C(R 12 ), X 13 is N or C(R 13 ), X 21 is N or C(R 21 ), X 22 is N or C(R 22 ), X 23 is N or C(R 23 ), X 31 is N or C(R 31 ), X 32 is N or C(R 32 ), X 33 is N or C(R 33 ), X 41 is N or C(R 41 ), X 42 is N or C(R 42 ), X 43 is N or C(R 43 ), and X 44 is N or C(R 44 ),

R 11 to R 13 are each independently the same as described in connection with R 1 in claim 1 , and two of R 11 to R 13 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 21 to R 23 are each independently the same as described in connection with R 2 in claim 1 , and two of R 21 to R 23 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 31 to R 33 are each independently the same as described in connection with R 3 in claim 1 , and two of R 31 to R 33 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 41 to R 44 are each independently the same as described in connection with R 4 in claim 1 , and two of R 41 to R 44 are optionally linked to form a substituted or unsubstituted C 5 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

two of R 11 to R 13 , R 21 to R 23 , R 31 to R 33 , and R 41 to R 44 are optionally linked to form a substituted or unsubstituted C 6 -C 30 carbocyclic group or a substituted or unsubstituted C 1 -C 30 heterocyclic group,

R 61 and R 71 are each independently the same as described in connection with R 1 in claim 1 ,

a61 and a71 are each independently 0, 1, 2, or 3,

T 4 is C or Si,

T 5 is selected from a single bond, *—O—*′, *—S—*′, *—C(R 7 )(R 8 )—*′, *—C(R 7 )=*′, *═C(R 8 )—*′, *—C(R 7 )═C(R 8 )—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—N(R 7 )—*, *—Si(R 7 )(R 8 )—*′, and *—P(R 7 )(R 8 )—*′,

R 7 and R 8 are each independently the same as described in connection with R 5 in claim 1 , and

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

15. The organometallic compound of claim 1 , wherein

the organometallic compound is one of Compounds 1 to 132:

16. 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, wherein the organic layer comprising an emission layer,

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

17. The organic light-emitting device of claim 16 , 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, or any combination thereof, and

the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

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

the emission layer comprises the organometallic compound.

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

the emission layer further comprises a host, and

an amount of the host is larger than an amount of the organometallic compound.

20. A diagnosis composition comprising at least one organometallic compound of claim 1 .