Compound, dispersant and toner

1. A compound represented by formula (2) or a tautomer thereof:

wherein:

R 5 represents an alkyl group having 2 to 12 carbon atoms or a benzyl group;

R 6 represents an alkylene group having 2 to 4 carbon atoms; and

W 2 represents an amino group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, or a methacryloylamino group.

2. The compound according to claim 1 , wherein W 2 in the formula (2) is an acryloyloxy group or a methacryloyloxy group.

3. The compound according to claim 1 , wherein R 5 in the formula (2) is an alkyl group having 2 to 8 carbon atoms.

4. A dispersant comprising a structure in which a structure represented by formula (3) or a tautomer thereof is bonded with a polymer moiety:

wherein:

each of X 2 , Y 2 , and Z 2 is, independently, —O—, a methylene group, or —NR 10 —;

R 10 represents hydrogen or a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms;

R 7 represents an unsubstituted or substituted phenyl group, a polycyclic aromatic group, or a heterocyclic group;

R 8 represents a hydrogen atom, an unsubstituted or substituted phenyl group, an aralkyl group, a straight-chain, branched-chain or cyclic alkyl group having 1 to 18 carbon atoms, or a monovalent group derived from an alkyl group having 1 to 18 carbon atoms by replacing a methylene group thereof by an ether bond, an ester bond, or an amide bond;

R 9 represents an unsubstituted or substituted phenylene group, a straight-chain, branched-chain or cyclic alkylene group having 1 to 18 carbon atoms, or a divalent group derived from an alkylene group having 1 to 18 carbon atoms by replacing a methylene group in the main chain thereof by an ether bond, an ester bond, or an amide bond;

W 3 represents a linking moiety to the polymer moiety;

a substituent of the substituted phenyl group and a substituent of the substituted phenylene group are each a methyl group, a methoxy group, a hydroxy group, a nitro group, a chloro group, a carboxy group, an amino group, a dimethylamino group, a carboxylic acid amide group, or a ureido group;

the polycyclic aromatic group is a group derived from naphthalene, anthracene, phenanthrene, or anthraquinone by removing one hydrogen atom therefrom; and

the heterocyclic group is a group derived from imidazole, oxazole, thiazole, pyridine, indole, benzimidazole, benzimidazolinone, or phthalimide by removing one hydrogen atom therefrom.

5. The dispersant according to claim 4 , wherein the structure represented by the formula (3) or the tautomer thereof is a structure represented by formula (4) or a tautomer thereof:

wherein:

R 11 represents an alkyl group having 2 to 12 carbon atoms or a benzyl group;

R 12 represents an alkylene group having 2 to 4 carbon atoms; and

W 4 represents a linking moiety to a polymer moiety, and the linking moiety is an ester bond or an amide bond.

6. The dispersant according to claim 5 , wherein the R 11 is an alkyl group having 2 to 8 carbon atoms.

7. The dispersant according to claim 4 , wherein the polymer moiety has a vinylic copolymer structure or a polyester structure.

8. The dispersant according to claim 7 , wherein the vinylic copolymer structure has at least one of a unit B originated from a compound B being an aromatic vinyl monomer and a unit C originated from a compound C being an acrylic acid-based monomer or a methacrylic acid-based monomer.

9. The dispersant according to claim 8 , wherein the dispersant satisfies formula (5):

0.01≦ a /( b+c )≦2.00  (5),

wherein:

a represents a content (parts by mole) of the structure represented by the formula (3);

b represents a content (parts by mole) of the unit B in terms of a molecular weight of the compound B; and

c represents a content (parts by mole) of the unit C in terms of a molecular weight of the compound C.

10. A toner comprising a toner particle comprising a binder resin, a coloring material, and a dispersant,

wherein the dispersant has a structure in which a structure represented by formula (3) or a tautomer thereof is bonded with a polymer moiety:

wherein:

each of X 2 , Y 2 , and Z 2 is, independently, —O—, a methylene group, or —NR 10 —;

R 10 represents hydrogen or a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms;

R 7 represents an unsubstituted or substituted phenyl group, a polycyclic aromatic group, or a heterocyclic group;

R 8 represents a hydrogen atom, an unsubstituted or substituted phenyl group, an aralkyl group, a straight-chain, branched-chain or cyclic alkyl group having 1 to 18 carbon atoms, or a monovalent group derived from an alkyl group having 1 to 18 carbon atoms by replacing a methylene group thereof by an ether bond, an ester bond, or an amide bond;

R 9 represents an unsubstituted or substituted phenylene group, a straight-chain, branched-chain or cyclic alkylene group having 1 to 18 carbon atoms, or a divalent group derived from an alkylene group having 1 to 18 carbon atoms by replacing a methylene group in the main chain thereof by an ether bond, an ester bond, or an amide bond;

W 3 represents a linking moiety to the polymer moiety;

a substituent of the substituted phenyl group and a substituent of the substituted phenylene group are each a methyl group, a methoxy group, a hydroxy group, a nitro group, a chloro group, a carboxy group, an amino group, a dimethylamino group, a carboxylic acid amide group, or a ureido group;

the polycyclic aromatic group is a group derived from naphthalene, anthracene, phenanthrene, or anthraquinone by removing one hydrogen atom therefrom; and

the heterocyclic group is a group derived from imidazole, oxazole, thiazole, pyridine, indole, benzimidazole, benzimidazolinone, or phthalimide by removing one hydrogen atom therefrom.