Polymerizable compound, and liquid crystal composition and liquid crystal display element in which the compound is used

A compound represented by general formula (i),

• wherein
• Ri1 independently represents a linear alkyl or halogenated alkyl group having 1 to 40 carbon atoms, or a branched alkyl having 3 to 40 carbon atoms, and a secondary carbon atom in the group is optionally replaced with —O—, —CH═CH—, or —C≡C— provided that oxygen atoms are not directly adjacent to each other,
• Ai1, Ai2, and Ai3 each independently represent a divalent aromatic group, a divalent cycloaliphatic group, or a divalent heterocyclic compound group;
• a hydrogen atom in Ai1 is optionally replaced with Li1, and hydrogen atoms in Ai2 and Ai3 are optionally replaced with Li1, Pi1-Spi1-, or Ki1;
• and Li1 represents a halogen atom, a cyano group, a nitro group, a linear alkyl or halogenated alkyl group having 1 to 40 carbon atoms, or a branched alkyl having 3 to 40 carbon atoms, and a secondary carbon atom in the alkyl group is optionally replaced with —CH═CH—, —C≡C—, —O—, —NH—, —COO—, or —OCO— provided that oxygen atoms are not directly adjacent to each other,
• Zi1 and Zi2 each independently represent a single bond, —CH═CH—, —CF═CF—, —C≡C—, —COO—, —OCO—, —OCOO—, —CF2O—, —OCF2—, —CH═CHCOO—, —OCOCH═CH—, —CH═C(CH3)COO—, —OCOC(CH3)═CH—, —CH2—CH(CH3)COO—, —OCOCH(CH3)—CH2—, —OCH2CH2O—, or an alkylene group having 2 to 20 carbon atoms, and one —CH2— group or two or more non-adjacent —CH2— groups in the alkylene group are optionally replaced with —O—, —COO—, or —OCO—,
• Ki1 is a group represented by one of general formulae (K-1) to (K-5),
• wherein
• Yi1 represents a linear or branched alkyl, halogenated alkyl, or cyanogenated alkyl group having 3 to 20 carbon atoms;
• at least two secondary carbon atoms in the alkyl group are replaced with —C(═Xi1)— and/or —CH(—CN)—;
• a secondary carbon atom in the alkyl group is optionally replaced with —CH═CH—, —C≡C—, —O—, —NH—, —COO—, or —OCO— provided that oxygen atoms are not directly adjacent to each other;
• a hydrogen atom in the alkyl group is optionally replaced with Pi1-Spi1-;
• and Xi1 represents an oxygen atom, a sulfur atom, NH, or NRi1,
• Si1 and Si3 each independently represent an alkylene group having 1 to 6 carbon atoms or a single bond, and —CH2— in the alkylene group is optionally replaced with —CH═CH—, —C≡C—, —C(═CH2)—, —C(═CHRi3)—, —C(═CRi32)—, —O—, —NH—, —C(═O)—, —COO—, or —OCO— provided that oxygen atoms are not directly adjacent to each other, Ri3 represents a linear alkyl group having 1 to 20 carbon atoms, or a branched alkyl group having 3 to 20 carbon atoms, and a secondary carbon atom in the alkyl group is optionally replaced with —O—, —CH═CH—, or —C≡C— provided that oxygen atoms are not directly adjacent to each other,
• Si2 represents a carbon atom,
• Ri2 represents a hydrogen atom or a linear alkyl having 1 to 20 carbon atoms or branched alkyl having 3 to 20 carbon atoms, and a secondary carbon atom in the group is optionally replaced with —O—, —CH═CH— or —C≡C— provided that oxygen atoms are not directly adjacent to each other,
• Pi1 represents a polymerizable group selected from the group consisting of the groups represented by general formulae (P-1) to (P-16),
• wherein a black dot at a right end represents a bond,
• SPi1 represents a spacer group or a single bond,
• ni1 represents an integer of 1 to 3, and ni2 represents 1 or 2, and ni3 represents an integer of 0 to 2;
• and ni1+ni2+ni3 is 3,
• Ri3 has a same meaning as Ri3 in general formula (i),
• in general formula (K-1), when any of Ri2, Xi1, Yi1, Si1, Si3, Pi1, and SPi1 is a plurality of units, the units are identical to or different from one another,
• wherein Si1, Pi1, and SPi1 have a same meaning as, respectively, Si1, Pi1, and SPi1 in general formula (K-1);
• RK21 represents a linear alkyl group having 1 to 10 carbon atoms, branched alkyl group having 3 to 10 carbon atoms, or halogenated alkyl or cyanogenated alkyl group having 1 to 10 carbon atoms, and at least one secondary carbon atom in the alkyl group is optionally replaced with —CH═CH—, —C≡C—, —O—, or —NH— provided that oxygen atoms are not directly adjacent to each other;
• and ni4 represents 1, and niK21 represents 0 or 1
• Pi1 is the same meaning as in general formula (K-1),
• SPi1 represents a spacer group or a single bond,
• mi1 represents an integer of 0 to 3, and
• in general formula (i), when any of Ri1, Ai2, Zi2, Li1, Ki1, Xi1, Pi1, and SPi1 is a plurality of units, the units are identical to or different from one another.