Compound having tetrahydronaphthalene skeleton and liquid crystal composition containing same

A tetrahydronanhthalene derivative represented by a general formula (I)

• (wherein, R represents a saturated or unsaturated alkyl group or alkoxyl group of 1 to 20 carbon atoms which may incorporate a branched chain and may be substituted with 1 to 7 fluorine atoms or alkoxyl groups of 1 to 7 carbon atoms;
• linkage groups La, Lb, Lc and Ld each represent independently a single bond, —CH2CH2—, —CH═CH—, —CH(CH3)CH2—, —CH2CH(CH3)—, —CH(CH3)CH(CH3)—, —CF2CF2—, —CF═CF—, —CH2O—, —OCH2—, —OCH(CH3)—, —CH(CH3)O—, —C≡C—, —CF2O—, —OCF2—, —COO—, —OCO—, —COS— or —SCO—;
• Z represents a fluorine atom, chlorine atom, cyano group, cyanato group, trifluoromethoxy group or a difluoromethoxy group;
• ring A, rind B and ring D each represent independently a trans-1,4-cyclohexylene group, a trans-decahydronaphthalene-2,6-diyl group, a trans-1,3-dioxane-2,4-diyl group, or a 1,4-phenylene group which may be substituted with one or two fluorine atoms, a pyridine-2,5-diyl group, a pyrimidine-2,5-diyl group, a pyrazine-2,5-diyl group, a pyridazine-3,6-diyl group, and a naphthalene-2,6-diyl group which may be substituted with one or two fluorine atoms;
• ring E represents independently a 1,4-phenylene group which may be substituted with one or two fluorine atoms, and a naphthalene-2,6-diyl group which may be substituted with one or two fluorine atoms, ring C represents either one of a general formula (IIa) and a general formula (IIb)
• (wherein, X1, X2, X3, X4, X5 and X6 each represent independently a hydrogen atom or a fluorine atom):
• and na, nb, nc and nd each represent independently either 0 or 1;
• although, in a case in which nc=1 and nd=0, ring D represents a 1,4-phenylene group which may be substituted with one or two fluorine atoms and/or a naphthalene-2,6-diyl group which may be substituted with one or two fluorine atoms;
• in a case in which Z is a cyano group, R is an unsubstituted and saturated alkyl group or alkoxyl group, na=nc=nd=0 and nb=1, or nb=nc=nd=0 and na=1, ring A and ring B are 1,4-phenylene groups, La and Lb are single bonds, and ring C is said general formula (IIa), then at least one of X1, X2 and X3 represents a fluorine atom;
• in a case in which Z is a cyano group, R is an unsubstituted and saturated alkyl group or alkoxyl group, na=nb=nc=0 and nd=1, or na=nb=nd=0 and nc=1, ring E and ring D are 1,4-phenylene groups, Lc and Ld are single bonds or —COO— linkages, and ring C is said general formula (IIa), then at least one of X1, X2 and X3 represents a fluorine atom;
• in a case in which Z is a cyano group, R is an unsubstituted and saturated alkyl group or alkoxyl group, na=nb=nc=0 and nd=1, or na=nb=nd=0 and nc=1, ring E and ring D are 1,4-phenylene groups, Lc and Ld are single bonds or —COO— linkages, and ring C is said general formula (IIb), then at least one of X4, X5 and X6 represents a fluorine atom;
• in a case in which Z is a fluorine atom, R is an unsubstituted and saturated alkyl group or alkoxyl group na=nb=nc=0 and nd=1, or na=nb=nd=0 and nc=1, ring E and ring D are 1,4-phenylene groups, Lc and Ld are —COO— linkages, and ring C is said general formula (IIb), then at least one of X4, X5 and X6 represents a fluorine atom;
• and in a case in which ring C is said general formula (IIb), at least one of nc and nd is 1), wherein in said general formula (I), Z is a trifluoromethoxy group.