Polycyclic aromatic compound

1. A polycyclic aromatic compound or a salt thereof represented by the following formula (I):

wherein

X represents B, P, P═O, P═S, P═Se, As, As═O, As═S, As═Se, Sb, Sb═O, Sb═S, Sb═Se, an optionally substituted metal in groups 3 to 11 in the periodic table, or an optionally substituted metal or metalloid in group 13 or 14 of the periodic table; and

ring A, ring B, ring C, and ring D are the same or different, and each represents an optionally substituted phenyl ring, an optionally substituted phenyl ring fused to an aryl or heteroaryl ring, an optionally substituted heteroaromatic ring, or an optionally substituted heteroaromatic ring fused to an aryl or heteroaryl ring,

wherein at least one of ring A, ring B, ring C, and ring D is an optionally substituted heteroaromatic ring, or an optionally substituted heteroaromatic ring fused to an aryl or heteroaryl ring,

wherein the heteroaromatic ring of ring A, ring B, ring C, and ring D is selected from the group consisting of thiophene, pyrrole and pyridine, and

wherein the compound represented by formula (I) is not a heterofullerene.

2. The polycyclic aromatic compound or salt thereof according to claim 1 , represented by the following formula (II):

wherein

Y a s are the same or different, and each represents C— or N; or two adjacent Y a s on the same ring, together with a bond therebetween, form N—, or S; provided that all Y a s do not represent C— at the same time; and

X represents B, P, P═O, P═S, P═Se, As, As═O, As═S, As═Se, Sb, Sb═O, Sb═S, Sb═Se, an optionally substituted metal in groups 3 to 11 in the periodic table, or an optionally substituted metal or metalloid in group 13 or 14 of the periodic table.

3. The polycyclic aromatic compound or salt thereof according to claim 1 , represented by any one of the following formulae (II-2) to (II-54):

wherein

X represents B, P, P═O, P═S, P═Se, As, As═O, As═S, As═Se, Sb, Sb═O, Sb═S, Sb═Se, an optionally substituted metal in groups 3 to 11 in the periodic table, or an optionally substituted metal or metalloid in group 13 or 14 of the periodic table; and

Z represents S, or N—.

4. The polycyclic aromatic compound or salt thereof according to claim 1 represented by the following formula (II′):

wherein

Ys are the same or different, and each represents CR or N; or two adjacent Ys on the same ring, together with a bond therebetween, form NR, or S; provided that all Ys do not represent C— at the same time;

X represents B, P, P═O, P═S, P═Se, As, As═O, As═S, As═Se, Sb, Sb═O, Sb═S, Sb═Se, an optionally substituted metal in groups 3 to 11 in the periodic table, or an optionally substituted metal or metalloid in group 13 or 14 of the periodic table;

R represents a hydrogen atom, halogen atom, C 1-20 alkyl group, hydroxy C 1-20 alkyl group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, mono- or di-aryl-substituted alkenyl group, mono- or di-heteroaryl-substituted alkenyl group, arylethynyl group, heteroarylethynyl group, hydroxy group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, cyano group, nitro group, amino group, monoalkylamino group, monoarylamino group, monoheteroarylamino group, carbazole group, C 1-20 alkoxycarbonylamino group, carbamoyl group, mono- or di-alkylcarbamoyl group, sulfamoyl group, mono- or di-alkylsulfamoyl group, C 1-20 alkylsulfonylamino group, C 1-20 alkylcarbonylamino group, aryl group, heteroaryl group, C 1-20 alkoxycarbonyl group, carboxyl group, 5-tetrazolyl group, sulfo group (—SO 2 OH), fluorosulfonyl group, SR a , N(R a ) 2 , B(R a ) 2 , Si(R a ) 3 , or —C≡C—Si(R a ) 3 ,

(wherein R a represents an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; or two R a s, together with an atom bound thereto, may form a bicyclic group or a tricyclic group optionally having a heteroatom);

provided that, the alkyl group, alkenyl group, alkynyl group, and alkoxy group are each optionally substituted with 1 to 3 atoms or groups, selected from the group consisting of halogen atom, hydroxy group, C 1-20 alkoxy group, aryloxy group, amino group, carbazole group, N(R a ) 2 (wherein R a is as defined above), trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, aryl group, and heteroaryl group; and the aryl group, aryl moiety, heteroaryl group, heteroaryl moiety, and carbazole group are each optionally substituted with 1 to 5 atoms or groups, selected from the group consisting of halogen atom, C 1-20 alkyl group, hydroxy C 1-20 alkyl group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, mono- or di-aryl-substituted alkenyl group, mono- or di-heteroaryl-substituted alkenyl group, arylethynyl group, heteroarylethynyl group, hydroxy group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, cyano group, nitro group, amino group, carbazole group, monoalkylamino group, monoarylamino group, monoheteroarylamino group, N(R a ) 2 (wherein R a is as defined above), carbamoyl group, mono- or di-alkylcarbamoyl group, sulfamoyl group, mono- or di-alkylsulfamoyl group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, C 1-20 alkylsulfonylamino group, C 1-20 alkylcarbonylamino group, methylenedioxy group, heteroaryl group, and aryl group, (wherein the aryl group is optionally substituted with 1 to 5 atoms or groups, selected from the group consisting of halogen atom, C 1-20 alkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, hydroxy group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, methylenedioxy group, cyano group, nitro group, amino group, carbazole group, and N(R a ) 2 (wherein R a is as defined above)); or,

two adjacent Rs on the same ring, together with a carbon atom bound thereto, form a five- or six-membered monocyclic aromatic group, bicyclic aromatic group, or tricyclic aromatic group optionally having a heteroatom; or

three adjacent Rs on the same ring, together with a carbon atom bound thereto, form a bicyclic aromatic group or a tricyclic group optionally having a heteroatom.

5. The polycyclic aromatic compound or salt thereof according to claim 1 represented by the following formulae (III′) to (XXIII′):

wherein

Ys are the same or different, and each represents CR or N; or two adjacent Ys on the same ring, together with a bond therebetween, form NR, or S; provided that all Ys do not represent C— at the same time;

X represents B, P, P═O, P═S, P═Se, As, As═O, As═S, As═Se, Sb, Sb═O, Sb═S, Sb═Se, an optionally substituted metal in groups 3 to 11 in the periodic table, or an optionally substituted metal or metalloid in group 13 or 14 of the periodic table; and

R represents a hydrogen atom, halogen atom, C 1-20 alkyl group, hydroxy C 1-20 alkyl group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, mono- or di-aryl-substituted alkenyl group, mono- or di- heteroaryl-substituted alkenyl group, arylethynyl group, heteroarylethynyl group, hydroxy group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, cyano group, nitro group, amino group, monoalkylamino group, monoarylamino group, monoheteroarylamino group, carbazole group, C 1-20 alkoxycarbonylamino group, carbamoyl group, mono- or di-alkylcarbamoyl group, sulfamoyl group, mono- or di-alkylsulfamoyl group, C 1-20 alkylsulfonylamino group, C 1-20 alkylcarbonylamino group, aryl group, heteroaryl group, C 1-20 alkoxycarbonyl group, carboxyl group, 5-tetrazolyl group, sulfo group (—SO 2 OH), fluorosulfonyl group, SR a , N(R a ) 2 , B(R a ) 2 , Si(R a ) 3 , or —C≡C—Si(R a ) 3

(wherein R a represents an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; or two R a s, together with an atom bound thereto, may form a bicyclic group or a tricyclic group optionally having a heteroatom);

provided that, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group are each optionally substituted with 1 to 3 atoms or groups, selected from the group consisting of halogen atom, hydroxy group, C 1-20 alkoxy group, aryloxy group, amino group, carbazole group, N(R a ) 2 (wherein R a is as defined above), trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, aryl group, and heteroaryl group; and

the aryl group, aryl moiety, heteroaryl group, heteroaryl moiety, and carbazole group are each optionally substituted with 1 to 5 atoms or groups, selected from the group consisting of halogen atom, C 1-20 alkyl group, hydroxy C 1-20 alkyl group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, mono- or di-aryl-substituted alkenyl group, mono- or di-heteroaryl-substituted alkenyl group, arylethynyl group, heteroarylethynyl group, hydroxy group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, cyano group, nitro group, amino group, carbazole group, monoalkylamino group, monoarylamino group, monoheteroarylamino group, N(R a ) 2 (wherein R a is as defined above), carbamoyl group, mono- or di-alkylcarbamoyl group, sulfamoyl group, mono- or di-alkylsulfamoyl group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, C 1-20 alkylsulfonylamino group, C 1-20 alkylcarbonylamino group, methylenedioxy group, heteroaryl group, and aryl group (wherein the aryl group is optionally substituted with 1 to 5 atoms or groups, selected from the group consisting of halogen atom, C 1-20 alkyl group, C 3-8 cycloalkyl group, C 2-20 alkenyl group, C 2-20 alkynyl group, hydroxy group, trifluoromethyl group, C 2-12 perfluoroalkyl group, C 1-20 alkoxy group, aryloxy group, trifluoromethoxy group, trifluoroethoxy group, C 2-12 perfluoroalkoxy group, C 1-20 alkylcarbonyl group, C 1-20 alkylsulfonyl group, methylenedioxy group, cyano group, nitro group, amino group, carbazole group, and N(R a ) 2 (wherein R a is as defined above); or,

two adjacent Rs on the same ring, together with a carbon atom bound thereto, form a five- or six-membered monocyclic aromatic group, bicyclic aromatic group, or tricyclic aromatic group optionally having a heteroatom; or

three adjacent Rs on the same ring, together with a carbon atom bound thereto, form a bicyclic aromatic group or a tricyclic aromatic group optionally having a heteroatom.

6. An electrochemical device comprising the compound according to claim 1 .

7. The electrochemical device according to claim 6 , wherein the device is an organic light-emitting element, an organic thin-film transistor, or an organic thin-film solar cell.