Triarylmethane compounds

A compound of the formula (I)

• where
• R1, R2 are hydrogen, a radical Ra or R1 and R2 together with the carbon atoms to which they are bound may also form a fused benzene ring, which is unsubstituted or substituted by one radical Ra,
• Y represents an alkylene group having 2, 3 or 4 carbon atoms,
• Ar is selected from the group consisting of mono-or polycyclic aryl having from 6 to 26 carbon atoms and mono-or polycyclic hetaryl having a total of 5 to 26 atoms, which are ring members, where 1, 2, 3 or 4 of these atoms are selected from nitrogen, sulphur and oxygen, while the remainder of these atoms are carbon atoms,
• where mono-or polycyclic aryl and mono-or polycyclic hetaryl are unsubstituted or carry 1, 2, 3 or 4 radicals RAr,
• X1, X2, X3, X4 are CH;
• Ra is selected from the group consisting of fluorine, cyclopropyl, cyclobutyl, CN, R, OR, CHnR3-n, NR2, C(O)R, C(O)NH2, CH═CH2, CH═CHR′, CH2-CH═CH2, CH2—CH═CHR′, CH2—C≡CH and CH2—C≡CR′;
• RAr is selected from the group consisting of fluorine, cyclopropyl, cyclobutyl, CN, R, OR, CHnR3-n, NR2, C(O)R, C(O)NH2, CH═CH2, CH═CHR′, CH2—CH═CH2, CH2—CH═CHR′, CH2—C≡CH and CH2—C≡CR′, wherein each RAr is identical or different if more than one RAr is present on each ring;
• R is selected from methyl and mono-or polycyclic hetaryl having a total of 5 to 26 atoms, which are ring members, where 1, 2, 3 or 4 of the ring atoms of hetaryl are selected from nitrogen and oxygen, while the remainder of these atoms are carbon atoms, where mono-or polycyclic aryl are unsubstituted or substituted by 1, 2, 3 or 4 identical or different radicals R″;
• R′ is selected from methyl, mono-or polycyclic aryl having from 6 to 26 carbon atoms and mono-or polycyclic hetaryl having a total of 5 to 26 atoms, which are ring members, where 1, 2, 3 or 4 of the ring atoms of hetaryl are selected from nitrogen and oxygen, while the remainder of these atoms are carbon atoms, where mono-or polycyclic aryl are unsubstituted or substituted by 1, 2, 3 or 4 identical or different radicals R″;
• R″ is selected from fluorine, cyclopropyl, cyclobutyl, phenyl, CN, OCH3, CH3, N(CH3)2, C(O)CH3, CH═CH2, CH═CHCH3, CH2—CH═CH2, CH2—CH═CH—CH3, CH2—C═CH and CH2—C≡C—CH3;
• and
• n on each occurrence is 0, 1, 2 or 3;
• where monocyclic aryl is phenyl;
• where polycyclic aryl is:
• a completely unsaturated polycyclic hydrocarbon radical, where each of the carbon atoms is part of a conjugate x-electron system,
• a polycyclic hydrocarbon radical which bears 1 phenyl ring which is fused to a saturated or unsaturated 4 to 10-membered mono-or bicyclic hydrocarbon ring, or a polycyclic hydrocarbon radical which bears at least 2 phenyl rings which are fused to each other directly and/or which are fused to a saturated or unsaturated 4 to 10-membered mono-or bicyclic hydrocarbon ring;
• where monocyclic hetaryl is a heteroaromatic monocycle, where the ring member atoms are part of a conjugate π-electron system, where the heteroaromatic monocycle has 5 or 6 ring atoms, which comprise 1, 2, 3 or 4 nitrogen atoms or 1 oxygen atom and 0, 1, 2 or 3 nitrogen atoms, or 1 sulphur atom and 0, 1, 2 or 3 nitrogen atoms, where the remainder of the ring atoms are carbon atoms;
• and
• where polycyclic hetaryl is:
• a heteroaromatic polycyclic radical, which bears a monocyclic hetaryl ring as defined above and at least one further aromatic ring selected from phenyl and heteroaromatic monocycles as defined above, where the aromatic rings of polycyclic hetaryl are linked to each other by a covalent bond and/or fused to each other directly and/or fused to a saturated or unsaturated 4 to 10-membered mono-or bicyclic hydrocarbon ring, or
• a heteroaromatic polycyclic radical, which bears at least one saturated or partially unsaturated 5- or 6-membered heterocyclic ring bearing 1 or 2 heteroatoms selected from oxygen, sulphur and nitrogen as ring atoms, and at least one further aromatic ring selected from phenyl and heteroaromatic monocycles, where at least one of the further aromatic rings is directly fused to the saturated or partially unsaturated 5- or 6-membered heterocyclic radical and where the remainder of further aromatic rings of polycyclic hetaryl are linked to each other by a covalent bond or fused to each other directly and/or fused to a saturated or unsaturated 4 to 10-membered mono-or bicyclic hydrocarbon ring.