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The present disclosure relates to dissymmetrical cationic diazo compounds having at least one 4-pyridinium unit and a cationic or non-cationic linker. The disclosure further relates to dyeing compositions comprising these compounds as a direct dye in a medium appropriate for the dyeing of keratin fi

The present disclosure relates to dissymmetrical cationic diazo compounds having at least one 4-pyridinium unit and a cationic or non-cationic linker. The disclosure further relates to dyeing compositions comprising these compounds as a direct dye in a medium appropriate for the dyeing of keratin fibers. Further, the disclosure relates to a method of coloring keratin fibers that employs this composition, and a device having a plurality of compartments.

대표청구항 ▼

What is claimed is: 1. A dissymmetrical cationic diazo compound chosen from those of formula (I), (II) and (III) below, their resonance forms, acid addition salts, and solvates, and mixtures thereof, wherein in the compounds of formulae (I), (II), and (III), the formula members attached to each sid

What is claimed is: 1. A dissymmetrical cationic diazo compound chosen from those of formula (I), (II) and (III) below, their resonance forms, acid addition salts, and solvates, and mixtures thereof, wherein in the compounds of formulae (I), (II), and (III), the formula members attached to each side of the linker L are either compositionally different or positionally different such that the compounds as a whole are dissymmetrical: wherein: the radicals R2, which are identical or different, independently of one another are chosen from: C1-C16 alkyl radicals optionally interrupted by at least one heteroatom and/or at least one group containing at least one heteroatom, said alkyl radicals being optionally substituted by at least one group chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, C1-C2 (di)alkylamino, thio (--SH), C1-C4 thioalkyl, C1-C4 alkylsulphinyl, and C1-C4 alkylsulphonyl groups; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (poly)hydroxyalkoxy groups; C2-C4 (poly)hydroxyalkylamino groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one hydroxyl group, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, and containing 5 to 7 ring members, wherein said heterocycle is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from hydrogen and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; optionally substituted aryl radicals; optionally substituted (C1-C4)alkylaryl radicals; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; thio groups (HS--); alkylthio groups (RS--) wherein R is an optionally substituted C1-C4 alkyl radical; and when e is 2, for each of the formulae (I), (II), and (III), two radicals R2 may optionally form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic, containing 5 or 6 ring members, which is optionally substituted by at least one identical or different group chosen from hydroxyl, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one group chosen from hydroxyl and methylcarbonylamino groups; e is an integer ranging from 0 to 4; when e is less than 4, the unsubstituted carbon atom(s) of the heterocycle of the formulae (I), (II), and (III) carry a hydrogen atom; the radicals R3, from formulae (I), (II), and (III), which are identical or different, independently of one another are chosen from: optionally substituted C1-C16 alkyl radicals optionally interrupted by at least one heteroatom or by at least one group containing at least one heteroatom; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (mono) or (poly)hydroxyalkoxy groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one group chosen from hydroxyl and C1-C4 alkoxy groups; wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, containing 5 to 7 ring members, and which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein the radical R is a C1-C4 alkyl radical and the radical R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; thio groups (HS--); alkylthio groups (RS--) wherein R is a C1-C4 alkyl radical; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; and when m' is greater than or equal to 2, two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic containing 6 ring members, which is optionally substituted by at least one identical or different group chosen from: hydroxyl,--NR4--Ph,--NR4--Ph--NR5R6,--NR4--Ph--OR7, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, C1-C4 alkylcarbonylamino, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group; m' is an integer from 0 to 4; when m' is less than 4, then the unsubstituted carbon atom(s) of the aromatic ring of the formulae (I), (II), and (III) carry a hydrogen atom; the W1 groups of the formulae (I), (II), and (III), which are identical or different, independently of one another, are chosen from: hydrogen atoms; halogen atoms chosen from bromine, chlorine and fluorine; and a group chosen from--NR5R6, OR7,--NR4--Ph--NR5R6,--NR4--Ph--OR7,--O--Ph--OR7 and--O--Ph--NR5R6 groups, wherein: R4 and R7, which may be identical or different, are independently chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted aryl or aralkyl radical and an optionally substituted phenyl radical; R5 and R6, which are identical or different, are chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted phenyl radical, an optionally substituted aryl or aralkyl radical and an alkylcarbonyl radical (R--CO--) wherein R is a C1-C4 alkyl radical; and R5 and R6 may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms, chosen from N, O and S, and containing 5 to 7 ring members, which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; or R5 and R6 may optionally form, with the carbon atom of the aromatic ring that is optionally substituted by a hydroxyl and adjacent to that to which--NR5R6 is attached, a 5-or 6-membered saturated or unsaturated heterocycle; Ph is an optionally substituted phenyl radical; L is chosen from a cationic linker and a non-cationic linker; and An is chosen from at least one identical or different cosmetically acceptable anions which ensure the electroneutrality of the compounds of formulas (I), (II) and (III). 2. The compound according to claim 1, wherein when R2 and/or R3 is chosen from optionally substituted C1-C16 alkyl radicals optionally interrupted by at least one heteroatom and/or at least one group containing at least one heteroatom, said heteroatoms and said groups are chosen from oxygen, nitrogen, sulphur,--CO--, SO2--, and combinations thereof. 3. The compound according to claim 1, wherein said radicals R2, which are identical or different, are chosen from: a halogen atom chosen from chlorine and fluorine; C1-C4 alkyl radicals optionally substituted by at least one identical or different radical chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, C1-C2 (di)alkylamino, thio (--SH), C1-C4 alkylsulphinyl, C1-C4 alkylsulphonyl and C1-C4 thioalkyl radicals; phenyl radicals optionally substituted by at least one identical or different radical chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino and C1-C2 (di)alkylamino radicals and a halogen atom; C1-C4 alkoxy radicals; C1-C4 alkylsulphonylamino radicals; C2-C4 (poly)hydroxyalkoxy radicals; an amino radical; C1-C2 (di)alkylamino radicals; C2-C4 (poly)hydroxyalkylamino radicals; alkylsulphonylamino radicals (RSO2--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl radicals ((R)2NSO2--) wherein said radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylthio radicals (RS--) wherein said radical R is a C1-C4 alkyl radical; alkylsulphinyl radicals (RSO--) wherein said radical R is a C1-C4 alkyl radical; alkylsulphonyl radicals (R--SO2--) wherein said radical R is a C1-C4 alkyl radical; and alkylcarbonylamino radicals (RCONR'--) wherein said radical R is chosen from a hydrogen atom and a C1-C4 alkyl radical and radical R' is chosen from a hydrogen atom and a C1-C4 alkyl radical. 4. The compound according to claim 1, wherein when e is 2 the two radicals R2 from formulae (I), (II), and (III) may optionally form, together with the carbon atoms to which they are attached, a secondary, 6-membered aromatic ring that is optionally substituted with at least one identical or different group chosen from hydroxyl, C1-C4 alkyl, C1-C4 alkoxy, amino, and amino substituted by one or two identical or different C1-C4 alkyl groups that optionally carry at least one hydroxyl or methylcarbonylamino group. 5. The compound according to claim 1, wherein the radicals R3, which may be identical or different, are chosen from: optionally substituted C1-C16 alkyl radicals; a halogen atom; a hydroxyl group; C1-C2 alkoxy radicals; a C2-C4 (poly)hydroxyalkoxy radical; an amino radical; amino radicals substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one identical or different group chosen from hydroxyl and C1-C4 alkoxy, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, the heterocycle containing 5 to 7 ring members, being saturated or unsaturated, aromatic or non-aromatic, and being optionally substituted; alkylcarbonylamino radicals (RCO--NR'--) wherein the radical R is a C1-C4 alkyl radical and the radical R' is chosen from a hydrogen and a C1-C4 alkyl radical; alkylsulphonylamino radicals (R'SO2--NR--) wherein the radical R is chosen from a hydrogen atom and a C1-C4 alkyl radical and the radical R' is a C1-C4 alkyl radical; aminosulphonyl radicals ((R)2N--SO2--) wherein the radicals R, which are identical or different, are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylthio radicals (RS--) wherein the radical R is a C1-C4 alkyl radical; and alkylsulphonyl radicals (R--SO2--) wherein the radical R is a C1-C4 alkyl radical. 6. The compound according to claim 1, wherein the radicals R3, which may be identical or different, are chosen from: C1-C4 alkyl radicals which are optionally substituted by at least one identical or different radical chosen from hydroxyl radicals, C1-C2 alkylcarbonylamino radicals, amino radicals substituted by two identical or different C1-C2 alkyl radicals which optionally carry at least one identical or different group chosen from hydroxyl or C1-C2 alkoxy, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a 5-or 6-membered heterocycle which is saturated or unsaturated and is optionally aromatic; C2-C4 hydroxyalkoxy radicals; a halogen chosen from chlorine and fluorine; an amino radical; amino radicals substituted by one or two identical or different C1-C2alkyl radicals which optionally carry at least one hydroxyl group; a methylcarbonylamino radical; a methylsulphonylamino radical; a hydroxyl radical; C1-C2 alkoxy radicals; and a methylsulphonyl radical. 7. The compound according to claim 6, wherein when R3 is chosen from C1-C4 alkyl radicals substituted by amino radicals substituted by two identical or different C1-C2 alkyl radicals and wherein when the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a 5-or 6-membered saturated or unsaturated and optionally aromatic heterocycle, said heterocycle is chosen from pyrrolidine, piperazine, homopiperazine, pyrrole, imidazole and pyrazole. 8. The compound according to claim 1, wherein when the coefficient m' is greater than or equal to 2, two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary, 6-membered aromatic ring optionally substituted by at least one identical or different group chosen from hydroxyl groups,--NR4--Ph,--NR4--Ph--NR5R6 and--NR4--Ph--OR7 groups, C1-C4 alkyl groups, C1-C4 alkoxy groups, C2-C4 (mono) or (poly)hydroxyalkoxy groups, C1-C4 alkylcarbonylamino groups, amino groups, and amino groups substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group. 9. The compound according to claim 8, wherein two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary, 6-membered aromatic ring which is optionally substituted by at least one identical or different group chosen from hydroxyl, methoxy, ethoxy, 2-hydroxyethyloxy, amino, methylcarbonylamino, (di)-2-hydroxyethylamino,--NH--Ph,--NH--Ph--NH2,--NH--Ph--NHCOCH3,--NH--Ph--OH and--NH--Ph--OCH3 groups. 10. The compound according to claim 1, wherein R4 and R7 independently of one another are chosen from: a hydrogen atom; C1-C6 alkyl radicals which are optionally substituted by at least one identical or different group; and an aryl or arylalkyl radical, the aryl moiety being optionally substituted by at least one identical or different group. 11. The compound according to claim 10, wherein when R4 and R7 independently of one another are chosen from an aryl or arylalkyl radical, the aryl moiety is optionally substituted by at least one identical or different group chosen from a chlorine atom, an amino group, a hydroxyl group, C1-C2 alkoxy groups and amino groups which are mono-or disubstituted by two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group. 12. The compound according to claim 10, wherein when R4 and R7 independently of one another are chosen from C1-C6 alkyl radicals, the alkyl radicals may be optionally substituted by at least one identical or different group chosen from hydroxyl and C1-C2 alkoxy. 13. The compound according to claim 1, wherein the radicals R5 and R6, which are identical or different, are chosen from: a hydrogen atom; alkylcarbonyl radicals (R--CO--) wherein R is an optionally substituted C1-C4 alkyl radical; a C1-C6 alkyl radical which is optionally substituted by at least one identical or non-identical group chosen from hydroxyl, C1-C2 alkoxy, amino, C1-C4 (di)alkylamino; the alkyl radical may further be substituted by at least one identical or different group chosen from C1-C4 alkylsulphonyl, C1-C4 alkylsulphinyl and C1-C4 alkylcarbonyl; and an aryl or arylalkyl radical, the awl moiety being optionally substituted by at least one identical or different radical. 14. The compound according to claim 13, wherein when the radicals R5 and R6, which are identical or different are chosen from an aryl or arylalkyl radical, the awl moiety may be optionally substituted by at least one identical or different radical chosen from a chlorine atom, an amino group, a hydroxyl group, a C1-C4 alkoxy group and an amino group which is mono-or disubstituted by two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group. 15. The compound according to claim 1, wherein the radicals R5 and R6, which are identical or different, are chosen from: a hydrogen atom; methylcarbonyl, ethylcarbonyl and propylcarbonyl radicals; optionally substituted C1-C3 alkyl radicals; and a phenyl radical which is optionally substituted by at least one identical or different radical chosen from hydroxyl radicals, C1-C2 alkoxy radicals, amino radicals, amino radicals substituted by at least one identical or different C1-C4 alkyl group which optionally carries at least one hydroxyl group. 16. The compound according to claim 15, wherein when the radicals R5, and R6, which are identical or different, are chosen from optionally substituted C1-C3 alkyl radicals, said radicals are chosen from methyl, ethyl, 2-hydroxyethyl and 2-methoxyethyl radicals. 17. The compound according to claim 1, wherein the heterocycle comprising from 5 to 7 ring members is chosen from the following heterocycles: piperidine, 2-(2-hydroxyethylpiperidine), 4-(aminomethyl)piperidine, 4-(2-hydroxyethyl)-piperidine, 4-(dimethylamino)piperidine, piperazine, 1-methylpiperazine, 1-(2-hydroxyethyl)piperazine, 1-(2-aminoethyl)piperazine, 1-hydroxyethylethoxypiperazine, homopiperazine, 1-methyl-1,4-perhydrodiazepine, pyrrole, 1,4-dimethylpyrrole, 1-methyl-4-ethylpyrrole, and 1-methyl-4-propylpyrrole. 18. The compound according to claim 1, wherein R5 and R6 may form, together with the carbon atom of the aromatic ring that is optionally substituted by a hydroxyl and adjacent to that to which--NR5R6 is attached, a 5-or 6-membered unsaturated heterocycle. 19. The compound according to claim 1, wherein L is a non-cationic linker chosen from: a covalent bond; an optionally substituted C1-C40 alkyl radical optionally interrupted by a saturated or unsaturated, aromatic or non-aromatic heterocycle comprising from 3 to 7 ring members, wherein said heterocycle may be optionally substituted and optionally fused; said alkyl radical being optionally interrupted by at least one heteroatom and/or by at least one group comprising at least one heteroatom, wherein the linker L does not comprise an azo, nitro, nitroso or peroxo bond; and an optionally substituted phenyl radical. 20. The compound according to claim 19, wherein when L is chosen from an optionally substituted C1-C40 alkyl radical optionally interrupted by at least one heteroatom or by at least one group containing at least one heteroatom, said heteroatoms and groups are chosen from oxygen, nitrogen, sulphur,--CO--, SO2--, and combinations thereof. 21. The compound according to claim 1, wherein L is a cationic linker chosen from a C2-C40 alkyl radical that carries at least one cationic charge and is optionally substituted and for interrupted by at least one saturated or unsaturated, aromatic or non-aromatic, identical or different heterocycle comprising from 3 to 7 ring members and/or optionally interrupted by at least one heteroatom and/or by at least one group comprising at least one heteroatom; wherein the linker L does not comprise an azo, nitro, nitroso or peroxo bond and the linker L carries at least one cationic charge. 22. The compound according to claim 21, wherein said heteroatoms and groups are chosen from oxygen, nitrogen, sulphur,--CO--, SO2--, and combinations thereof. 23. The compound according to claim 1, wherein An is chosen from an organic anion, inorganic anion, and an anion mixture allowing the charge or charges on the compounds of formula (I), (II) and (III) to be balanced and wherein An is chosen from halides, hydroxides, sulphates, hydrogensulphates, alkylsulphates wherein the alkyl moiety is linear or branched and is C1-C6, carbonates, hydrogen carbonates, carboxylic acid salts, alkylsulphonates wherein the alkyl moiety is linear or branched and is C1-C6 alkyl; arylsulphonates wherein the aryl moiety is optionally substituted with at least one C1-C4 alkyl, and alkylsulphonyls. 24. The compound according to claim 23, wherein in the definition of An, the halides are chosen from chloride, bromide, fluoride, and iodide, the alkylsulphates wherein the linear or branched alkyl moiety is C1-C6 are chosen from a methylsulphate ion and an ethylsulphate ion; the salts of carboxylic acids are chosen from formate, acetate, citrate, tartrate, and oxalate; the alkylsulphonates wherein the linear or branched alkyl moiety is C1-C6 are methylsulphonate ions; the aryl moiety of the arylsulphonates is phenyl and is optionally substituted by at least one C1-C4 alkyl radical chosen from 4-tolylsulphonate; and/or the alkylsulphonyls are chosen from mesylate. 25. The compound according to claim 1, wherein said compound is chosen from those of formula (I'), (I") (I'"), (II'), (II"), (II'"), (III'), (III"), and (III'") below, and resonance forms, acid addition salts, solvates, and mixtures thereof; wherein R3, W1, and m' are as defined in claim 1. 26. A dyeing composition comprising, in a medium suitable for dyeing of keratin fibers, a direct dye chosen from at least one compound chosen from those of formula (I), (II) and (III) below, acid addition salts, solvates, and mixtures thereof, wherein in the compounds of formulae (I), (II), and (III), the formula members attached to each side of the linker L are either compositionally different or positionally different such that the compounds as a whole are dissymmetrical: wherein: the radicals R2, which are identical or different, independently of one another are chosen from: C1-C16alkyl radicals optionally interrupted by at least one heteroatom and/or at least one group containing at least one heteroatom, said alkyl radicals being optionally substituted by at least one group chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, C1-C2 (di)alkylamino, thio (--SH), C1-C4 thioalkyl, C1-C4 alkylsulphinyl, and C1-C4 alkylsulphonyl groups; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (poly)hydroxyalkoxy groups; a C2-C4 (poly)hydroxyalkylamino groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one hydroxyl group, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, and containing 5 to 7 ring members, wherein said heterocycle is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from hydrogen and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2-NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; optionally substituted aryl radicals; optionally substituted (C1-C4)alkylaryl radicals; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; thio groups (HS--); alkylthio groups (RS--) wherein R is an optionally substituted C1-C4 alkyl radical; and when e is 2, for each of the formulae (I), (II), and (III), two radicals R2 may optionally form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic, containing 5 or 6 ring members, which is optionally substituted by at least one identical or different group chosen from hydroxyl, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, and amino substituted by one or two identical or different C1-C4alkyl radicals which optionally carry at least one group chosen from hydroxyl and methylcarbonylamino groups; e is an integer ranging from 0 to 4; when e is less than 4, the unsubstituted carbon atom(s) of the heterocycle of the formulae (I), (II), and (III) carry a hydrogen atom; the radicals R3, from formulae (I), (II), and (III), which are identical or different, independently of one another are chosen from: optionally substituted C1-C16 alkyl radicals optionally interrupted by at least one heteroatom or by at least one group containing at least one heteroatom; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (mono) or (poly)hydroxyalkoxy groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one group chosen from hydroxyl and C1-C4 alkoxy groups; wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, containing 5 to 7 ring members, and which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein the radical R is a C1-C4 alkyl radical and the radical R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; thio groups (HS--); alkylthio groups (RS--) wherein R is a C1-C4 alkyl radical; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; and when m' greater than or equal to 2, two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic containing 6 ring members, which is optionally substituted by at least one identical or different group chosen from: hydroxyl,--NR4--Ph,--NR4--Ph--NR5R6,--NR4--Ph--OR7, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, C1-C4 alkylcarbonylamino, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group; m' is an integer from 0 to 4; when m' is less than 4, then the unsubstituted carbon atom(s) of the aromatic ring of the formulae (I), (II), and (III) carry a hydrogen atom; the W1 groups of the formulae (I), (II), and (III), which are identical or different, independently of one another, are chosen from: hydrogen atoms; halogen atoms chosen from bromine, chlorine and fluorine; and a group chosen from--NR5R6, OR7,--NR4--Ph--NR5R6,--NR4--Ph--OR7,--O--Ph--OR7, and--O--Ph--NR5R6 groups, wherein: R4 and R7, which may be identical or different, are independently chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted aryl or aralkyl radical and an optionally substituted phenyl radical; R5 and R6, which are identical or different, are chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted phenyl radical, an optionally substituted aryl or aralkyl radical and an alkylcarbonyl radical (R--CO--) wherein R is a C1-C4 alkyl radical; and R5 and R6 may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms, chosen from N, O and S, and containing 5 to 7 ring members, which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; or R5 and R6 may optionally form, with the carbon atom of the aromatic ring that is optionally substituted by a hydroxyl and adjacent to that to which--NR5R6 is attached, a 5-or 6-membered saturated or unsaturated heterocycle; Ph is an optionally substituted phenyl radical; L is chosen from a cationic linker and a non-cationic linker; An is chosen from at least one identical or different cosmetically acceptable anions which ensure the electroneutrality of the compounds of formulas (I), (II) and (III). 27. The dyeing composition of claim 26, wherein said at least one compound of formula (I), (II) or (III) or of each of said compounds of formula (I), (II) or (III), is present in an amount ranging from 0.001% to 20% by weight relative to the total weight of the dyeing composition. 28. The dyeing composition of claim 27, wherein said at least one compound or each of said compounds of formula (I), (II) or (III) is present in an amount ranging from 0.02% to 10% by weight, relative to the total weight of the dyeing composition. 29. The dyeing composition of claim 26, wherein said dyeing composition further comprises at least one additional direct dye, and/or at least one oxidation base optionally in combination with at least one coupler. 30. The dyeing composition of claim 29, wherein said at least one additional direct dye is a cationic or nonionic dye chosen from nitrobenzene, azo, azomethine, methine, tetraazapentamethine, anthraquinone, naphthoquinone, benzoquinone, phenothiazine, indigoid, xanthene, phenanthridine, and phthalocyanine dyes, dyes derived from triarylmethane, and natural dyes, and mixtures thereof. 31. The dyeing composition of claim 29, wherein said at least one oxidation base is chosen from p-phenylenediamines, bisphenylalkylenediamines, o-aminophenols, p-aminophenols and heterocyclic bases. 32. The dyeing composition of claim 29, wherein said at least one coupler is chosen from m-aminophenols, m-phenylenediamines, m-diphenols, naphthalenic couplers, heterocyclic couplers, their acid addition salts, and mixtures thereof. 33. The dyeing composition of claim 26, wherein said dyeing composition further comprises at least one oxidizing agent. 34. A method of coloring keratin fibers, comprising contacting said fibers, which may be dry or wet, with a dyeing composition for a time sufficient to give a desired color, wherein the dyeing composition comprises, in a medium, suitable for dyeing keratin fibers, at least one direct dye chosen from those of formula (I), (II) and (III) below, acid addition salts thereof solvates thereof, and mixtures thereof wherein in the compounds of formulae (I), (II), and (III), the formula members attached to each side of the linker L are either compositionally different or positionally different such that the compounds as a whole are dissymmetrical: wherein: the radicals R2, which are identical or different, independently of one another are chosen from: C1-C16 alkyl radicals optionally interrupted by at least one heteroatom and/or at least one group containing at least one heteroatom, said alkyl radicals being optionally substituted by at least one group chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, C1-C2 (di)alkylamino, thio (--SH), C1-C4 thioalkyl, C1-C4 alkylsulphinyl, and C1-C4 alkylsulphonyl groups; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (poly)hydroxyalkoxy groups; C2-C4 (poly)hydroxyalkylamino groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one hydroxyl group, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, and containing 5 to 7 ring members, wherein said heterocycle is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from hydrogen and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; optionally substituted aryl radicals; optionally substituted (C1-C4)alkylaryl radicals; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; thio groups (HS--); alkylthio groups (RS--) wherein R is an optionally substituted C1-C4 alkyl radical; and when e is 2, for each of the formulae (I), (II), and (III), two radicals R2 may optionally form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic, containing 5 or 6 ring members, which is optionally substituted by at least one identical or different group chosen from hydroxyl, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one group chosen from hydroxyl and methylcarbonylamino groups; e is an integer ranging from 0 to 4; when e is less than 4, the unsubstituted carbon atom(s) of the heterocycle of the formulae (I), (II), and (III) carry a hydrogen atom; the radicals R3, from formulae (I), (II), and (III), which are identical or different, independently of one another are chosen from: optionally substituted C1-C16 alkyl radicals optionally interrupted by at least one heteroatom or by at least one group containing at least one heteroatom; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (mono) or (poly)hydroxyalkoxy groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one group chosen from hydroxyl and C1-C4 alkoxy groups; wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, containing 5 to 7 ring members, and which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein the radical R is a C1-C4 alkyl radical and the radical R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2-CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; thio groups (HS--); alkylthio groups (RS--) wherein R is a C1-C4 alkyl radical; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; and when m' is greater than or equal to 2, two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic containing 6 ring members, which is optionally substituted by at least one identical or different group chosen from: hydroxyl,--NR4--Ph,--NR4--Ph--NR5R6,--NR4--Ph--OR7, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, C1-C4 alkylcarbonylamino, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group; m' is an integer from 0 to 4; when m' is less than 4, then the unsubstituted carbon atom(s) of the aromatic ring of the formulae (I), (II), and (III) carry a hydrogen atom; the W1 groups of the formulae (I), (II), and (III), which are identical or different, independently of one another, are chosen from: hydrogen atoms; halogen atoms chosen from bromine, chlorine and fluorine; and a group chosen from--NR5R6, OR7,--NR4--Ph--NR5R6,--NR4--Ph--OR7,--O--Ph--OR7 and--O--Ph--NR5R6 groups, wherein: R4 and R7, which may be identical or different, are independently chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted aryl or aralkyl radical and an optionally substituted phenyl radical; R5 and R6, which are identical or different, are chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted phenyl radical, an optionally substituted aryl or aralkyl radical and an alkylcarbonyl radical (R--CO--) wherein R is a C1-C4 alkyl radical; and R5 and R6 may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms, chosen from N, O and S, and containing 5 to 7 ring members, which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; or R5 and R6 may optionally form, with the carbon atom of the aromatic ring that is optionally substituted by a hydroxyl and adjacent to that to which--NR5R6 is attached, a 5-or 6-membered saturated or unsaturated heterocycle; Ph is an optionally substituted phenyl radical; L is chosen from a cationic linker and a non-cationic linker; An is chosen from at least one identical or different cosmetically acceptable anions which ensure the electroneutrality of the compounds of formulas (I), (II) and (III). 35. A device comprising a plurality of compartments, in which a first compartment comprises a dyeing composition and a second compartment comprises an oxidizing composition, wherein said dyeing composition comprises, in a medium suitable for dyeing keratin fibers, at least one direct dye chosen from those of formula (I), (II) and (III) below, acid addition salts, solvates, and mixtures thereof, wherein in the compounds of formulae (I), (II), and (III), the formula members attached to each side of the linker L are either compositionally different or positionally different such that the compounds as a whole are dissymmetrical: wherein: the radicals R2, which are identical or different, independently of one another are chosen from: C1-C16 alkyl radicals optionally interrupted by at least one heteroatom and/or at least one group containing at least one heteroatom, said alkyl radicals being optionally substituted by at least one group chosen from hydroxyl, C1-C2 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, C1-C2 (di)alkylamino, thio (--SH), C1-C4 thioalkyl, C1-C4 alkylsulphinyl, and C1-C4 alkylsulphonyl groups; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (poly)hydroxyalkoxy groups; C2-C4 (poly)hydroxyalkylamino groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one hydroxyl group, wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, and containing 5 to 7 ring members, wherein said heterocycle is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from hydrogen and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein R is a C1-C4 alkyl radical and R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; optionally substituted aryl radicals; optionally substituted (C1-C4)alkylaryl radicals; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; thio groups (HS--); alkylthio groups (RS--) wherein R is an optionally substituted C1-C4 alkyl radical; and when e is 2, for each of the formulae (I), (II), and (III), two radicals R2 may optionally form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic, containing 5 or 6 ring members, which is optionally substituted by at least one identical or different group chosen from hydroxyl, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one group chosen from hydroxyl and methylcarbonylamino groups; e is an integer ranging from 0 to 4; when e is less than 4, the unsubstituted carbon atom(s) of the heterocycle of the formulae (I), (II), and (III) carry a hydrogen atom; the radicals R3, from formulae (I), (II), and (III), which are identical or different, independently of one another are chosen from: optionally substituted C1-C16 alkyl radicals optionally interrupted by at least one heteroatom or by at least one group containing at least one heteroatom; hydroxyl groups; C1-C4 alkoxy groups; C2-C4 (mono) or (poly)hydroxyalkoxy groups; alkoxycarbonyl groups (RO--CO--) wherein R is a C1-C4 alkyl radical; alkylcarbonyloxy groups (RCO--O--) wherein R is a C1-C4 alkyl radical; alkylcarbonyl groups (R--CO--) wherein R is a C1-C4 alkyl radical; amino groups; amino groups substituted by one or two identical or different C1-C4 alkyl radicals optionally carrying at least one group chosen from hydroxyl and C1-C4 alkoxy groups; wherein the two alkyl radicals may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms chosen from N, O and S, containing 5 to 7 ring members, and which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; alkylcarbonylamino groups (RCO--NR'--) wherein the radical R is a C1-C4 alkyl radical and the radical R' is chosen from a hydrogen atom and a C1-C4 alkyl radical; aminocarbonyl groups ((R)2N--CO--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; ureido groups (N(R)2--CO--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; aminosulphonyl groups ((R)2N--SO2--) wherein radicals R independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; alkylsulphonylamino groups (RSO2--NR'--) wherein radicals R and R' independently of one another are chosen from a hydrogen atom and a C1-C4 alkyl radical; thio groups (HS--); alkylthio groups (RS--) wherein R is a C1-C4 alkyl radical; alkylsulphinyl groups (R--SO--) wherein R is a C1-C4 alkyl radical; alkylsulphonyl groups (R--SO2--) wherein R is a C1-C4 alkyl radical; nitro groups; cyano groups; halogen atoms; and when m' greater than or equal to 2, two adjacent radicals R3 may form, with the carbon atoms to which they are attached, a secondary ring, aromatic or non-aromatic containing 6 ring members, which is optionally substituted by at least one identical or different group chosen from: hydroxyl,--NR4--Ph,--NR4--Ph--NR5R6,--NR4--Ph--OR7, C1-C4 alkyl, C1-C4 alkoxy, C2-C4 (poly)hydroxyalkoxy, C1-C4 alkylcarbonylamino, amino, and amino substituted by one or two identical or different C1-C4 alkyl radicals which optionally carry at least one hydroxyl group; m' is an integer from 0 to 4; when m' is less than 4, then the unsubstituted carbon atom(s) of the aromatic ring of the formulae (I), (II), and (III) carry a hydrogen atom; the W1 groups of the formulae (I), (II), and (III), which are identical or different, independently of one another, are chosen from: hydrogen atoms; halogen atoms chosen from bromine, chlorine and fluorine; and a group chosen from--NR5R6, OR7,--NR4--Ph--NR5R6,--NR4--Ph--OR7,--O--Ph--OR7 and--O--Ph--NR5R6 groups, wherein: R4 and R7, which may be identical or different, are independently chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted aryl or aralkyl radical and an optionally substituted phenyl radical; R5 and R6, which are identical or different, are chosen from a hydrogen atom, an optionally substituted C1-C20 alkyl radical, an optionally substituted phenyl radical, an optionally substituted aryl or aralkyl radical and an alkylcarbonyl radical (R--CO--) wherein R is a C1-C4 alkyl radical; and R5 and R6 may optionally form, with the nitrogen atom to which they are attached, a heterocycle containing 1 to 3 heteroatoms, chosen from N, O and S, and containing 5 to 7 ring members, which is saturated or unsaturated, aromatic or non-aromatic and is optionally substituted; or R5 and R6 may optionally form, with the carbon atom of the aromatic ring that is optionally substituted by a hydroxyl and adjacent to that to which--NR5R6 is attached, a 5-or 6-membered saturated or unsaturated heterocycle; Ph is an optionally substituted phenyl radical; L is chosen from a cationic linker and a non-cationic linker; An is chosen from at least one identical or different cosmetically acceptable anions which ensure the electroneutrality of the compounds of formulas (I), (II) and (III).