Liquid crystal composition and liquid crystal display device

A liquid crystal composition that has negative dielectric anisotropy, and contains at least one compound represented by formula (1) as a first additive, and at least one compound represented by formula (2) as a first component:

• wherein, in formula (1) and formula (2), R1 is hydrogen, halogen, alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, alkyl having 1 to 12 carbons in which at least one hydrogen is replaced by fluorine or chlorine, or alkenyl having 2 to 12 carbons in which at least one hydrogen is replaced by fluorine or chlorine;
• R2 is a group represented by —OH, —OR0, —NH2, —NHR0 or —N(R0)2, in which R0 is alkyl having 1 to 5 carbons, and in the alkyl, at least one —CH2— may be replaced by —O—, and at least one —CH2CH2— may be replaced by —CH═CH—, and in these groups, at least one hydrogen may be replaced by fluorine;
• R3 and R4 are independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenyloxy having 2 to 12 carbons;
• ring A and ring B are independently, 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, naphthalene-1,2-diyl, naphthalene-1,3-diyl, naphthalene-1,4-diyl, naphthalene-1,5-diyl, naphthalene-1,6-diyl, naphthalene-1,7-diyl, naphthalene-1,8-diyl, naphthalene-2,3-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, fluorene-2,7-diyl, phenanthrene-2,7-diyl or anthracen-2,6-diyl, and in the rings, at least one hydrogen may be replaced by fluorine, chlorine, alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, or alkyl having 1 to 12 carbons in which at least one hydrogen is replaced by fluorine or chlorine;
• ring C is 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine, or tetrahydropyran-2,5-diyl;
• ring D is 1,4-phenylene in which at least one hydrogen is replaced by fluorine or chlorine;
• Z1 is a single bond, —CH2CH2—, —CH═CH—, —C≡C—, —COO—, —OCO—, —CF2O—, —OCF2—, —CH2O—, —OCH2— or —CF═CF—;
• Z2 and Z3 are independently a single bond, —CH2CH2—, —CH2O—, —OCH2—, —COO— or —OCO—;
• Sp1 and Sp2 are independently a single bond or alkylene having 1 to 7 carbons, and in the alkylene, at least one —CH2— may be replaced by —O—, —COO— or —OCO—, and at least one —CH2CH2— may be replaced by —CH═CH—, and in these groups, at least one hydrogen may be replaced by fluorine;
• a is 0, 1, 2, 3 or 4;
• and b is 0 or 1.