Liquid crystal compound having hydrogen as a terminal group, composition comprising the compound, and liquid crystal display element comprising the composition

A compound represented by the following formula (1):

• wherein Ra is alkyl having 1 to 15 carbons and any —CH2— in the alkyl may be replaced by —O—, —S—, —CH═CH—, or —C≡C—;
• A1, A2 and A3 independently are 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, decahydronaphthalene-2,6-diyl, 1,4-phenylene in which any hydrogen may be replaced by fluorine, naphthalene-2,6-diyl in which any hydrogen may be replaced by fluorine, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl in which any —CH═ may be replaced by —CF═;
• Z1, Z2 and Z3 independently are a single bond, —(CH2)2—, —(CF2)2—, —COO—, —OCO—, —CH2O—, —OCH2—, —CF2O—, —OCF2—, —CH═CH—, —CF═CF—, —C≡C—, —(CH2)4—, —(CH2)3O—, or —O(CH2)3—;
• n and m independently are 0 or 1;
• phenyl having (F)p is phenyl, 2-fluorophenyl, 2,5-difluorophenyl, 2,3,5-trifluorophenyl, or 2,3,6-trifluorophenyl;
• with the proviso that when A1, A2 and A3 are 1,4-phenylene in which any hydrogen may be replaced by fluorine and Z1, Z2 and Z3 are a single bond, the total number of fluorine in formula (1) is at least two;
• and with the further proviso that the following compounds are excluded:
• wherein R is alkoxy or alkoxyalkoxy, and
• wherein R1 is alkyl, either one of a1 or a2 is fluorine and the other thereof is hydrogen.