Cyclohexylene reactive mesogens and their applications

A liquid-crystal medium comprising one or more compounds of formula I

• R1-A-(B)b—R2 I
• wherein
• R1 and R2 are independently of each other selected from H, F, Cl, Br, I, CN, NCS, SF5, or straight-chain or branched alkyl having 1 to 30 C-atoms that is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by —O—, —S—, —NH—, —NR0—, —SiR0R00—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —CY1═CY2— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another, or denote P-Sp-, wherein at least one of R1 and R2 is P-Sp,
• R0 and R00 independently of each other denote H or alkyl with 1 to 12 C-atoms,
• Y1 and Y2 independently of each other denote H or F,
• P is a polymerizable group,
• Sp is a SP′-X′ or a single bond,
• Sp′ is alkylene with 1 to 20 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by —O—, —S—, —NH—, —NR0—, —SiR0R00—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR0—CO—O—, —O—CO—NR0—, —NR0—CO—NR0—, —CH═CH— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another,
• X′ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0—, —NR0—CO—, —NR0—CO—NR0—, —OCH2—, —CH2O—, —SCH2—, CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CF2CH2—, —CH2CF2—, —CF2CF2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0—, —CY1═CY2—, —C≡C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond,
• A and B are independently of each other 1,4-cyclohexylene wherein one or more —CH2— groups are optionally replaced by —O— and/or —S—, in such a way, that no two O-atoms are linked together and that is optionally substituted, and
• b is 0 or 1,
• wherein at least one of R1 and R2 is P-Sp′-X′— in which X′ is not a single bond, and if only one of R1 and R2 is P-Sp′-X′— then X′ is not —O— or —CH2O— and Sp′ is not an alkylene with 1 to 20 C atoms wherein only one CH2 group is replaced and it replaced by —O—.

A compound according to formula I

• R1-A-(B)b-R2 I
• wherein
• R1 and R2 are independently of each other P-Sp′-X′—,
• P is a polymerizable group,
• Sp′ is alkylene with 1 to 20 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by —O—, —S—, —NH—, —NR0—,—SiR0R00—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR0—CO—O—,—O—CO—NR0—, —NR0—CO—NR0—, —CH═CH— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another,
• X′ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0—, —NR0—CO—, —NR0—CO—NR0—, —OCH2—, —CH2O—, —SCH2—,—CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CF2CH213 , —CH2CF2—, —CF2CF2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0—, —CY1═CY213 , —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond,
• R0 and R00 independently of each other denote H or alkyl with 1 to 12 C-atoms,
• Y1 and Y2 independently of each other denote H or F,
• A and B are independently of each other 1,4-cyclohexylene wherein one or more —CH2— groups are optionally replaced by —O— and/or —S—, in such a way, that no two O-atoms are linked together and that is optionally substituted, and
• b is 0 or 1;
• with the proviso that compounds wherein:
• b is 0,
• P is acrylate or methacrylate,
• Sp′ is a single bond or a —CH2— group, and
• X′ is a single bond,
• are excluded.

A compound selected from the following formulae IB to ID

• wherein
• R1 is selected from H, F, Cl, Br, I, CN, NCS, SF5, or straight-chain or branched alkyl having 1 to 30 C-atoms that is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by —O—, —S—, —NH—, —NR0, —SiR0R00—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —CY1═CY2— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another,
• Y1 and Y2 independently of each other denote H or F,
• P, P1 and P2 are, independently of each other, a polymerizable group,
• X, X1 and X2 are, independently of each other, —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR0—, —NR0—CO—, —NR0—CO—NR0—, —OCH2—, —CH2O—, —SCH2—,—CH2S—, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CF2CH2—, —CH2CF2—, —CF2CF2—, —CH═N—, —N═CH—, —N═N—, —CH═CR0—, —CY1═CY2—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond, and
• Sp, Sp1 and Sp2 are, independently of each other, alkylene with 1 to 20 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are optionally replaced, in each case independently from one another, by —O—, —S—, —NH—, —NR0—,—SiR0R00—, —CO—, —COO—,—OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR0—CO—O—, —O—CO—NR0—, —NR0—CO—NR0—, —CH═CH— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another,
• with the proviso that compounds of Formula IB wherein P1 and P2 are acrylate or methacrylate, and Sp1-X1— and Sp2-X2— are a single bond or a —CH2— group are excluded.