GB2269383A - Ferrocene compounds for liquid crystals - Google Patents

Abstract

A ferrocene compound characterised by Formula V: <IMAGE> wherein R<1> is selected from alkyl, alkoxy, hydrogen, halogen, and CN, and R<2> is an ester group containing one or more 1, 4 phenylene or ferrocene moieties (where more than one such moiety is present, they are linked by CO2, O2C, N=CH, HC=N or a single bond) which may be substituted by alkyl, alkoxy, hydrogen, halogen, CN, and OH. Such compounds can be used as component(s) of liquid crystalline materials. The liquid crystalline materials and the ferrocene compounds can be used in liquid crystal devices.

Description

FERROECENE COMPOUNDS MATERIALS, AND DEVICES CONTAINING THEM.

This invention relates to ferrocene compounds, materials containing such compounds and also to devices incorporating such compounds or materials.

The first ferrocene containing compound thought to show mesogenic (liquid-crystalline) properties was ferroecenecarboxaldehyde (P J Graham et al, 1957, J Am Chem Soc., 79, p3416), although subsequent investigations (L Verbit and T R Halbert, 1975, Nol Cryst liq Cryst..

30, p209; and J M Wilson et al, 1977, flol Cryst Uq Cryst., 34, p237) assigned the mesophase as a disordered crystal. Truly mesogenic derivatives of ferroecene are described by J Malthete and J Billard, 1976, flol Cryst Liq Cryst Lett., 34, p117, where nematic phases were reported in compounds of Formula I:

Formula I

co2- OOCH2OH2 R = alkyl or alkoxy and Y = Fe or Fe More recently, diesters of ferrocene of Formula IIa have been reported (J Bhatt et al, 1988, J Chem Soc Chem Comm, pal439), and several of the examples show monotropic smectic A and C phases; the monosubstituted ferroecene esters of Formula IIb were found to be non-mesogenic, but similar derivatives of Formula IIc, show smectic phases.

Formula lia

Formula IIb

Formula IIc Compounds of Formula 111 have been reported (P Singh et al, 1991, Liquid Crystals, 9, pl9) and are described as smectogenic when R1 = R2 = OC7H15 and nematogenic when R1 = R2 = OC10H21 or R1 = OCtoH2l, or R1 = OC10H21 and R2 = OH. The clearing temperatures of the mesophases appear not to be reversible and the nematic phase is seen only on considerable supercooling of the isotropic liquid.

Formula III R1 = R2 = OC7H15 or OC10H21 and R1 = OCIdH21, R2 = OH Other known ferrocene compounds are described in R Deschenaux and J-L Marendaz, 1991, J Chem Soc, Chem Comm, p909, where 1,3-disubstituted ferrocene derivatives with structures as seen in Formula IVa show enantiotropic nematic phases whereas for corresponding l,l'-derivatives of Formula IVb, only that in which R = (a) hexyloxy shows a nematic phase, where this phase is monotropic.

Formula IV

According to this invention ferrecene compounds are provided of Formula V:

Formula V wherein R1 is selected from alkyl, alkoxy, hydrogen, halogen, and CN, and R2 is (A-Z)n (A-Z)n (A ,Z )p (A4-Z4)q (R3) Formula VI where each of At, A2, A3 and A4 are independently selected from CO2, 02C, N=CH, HC=N and a single bond, Z, Z2' Z3 and Z4 are independently selected from 1,4 phenylene, and ferrocene, R3 is selected from alkyl, alkoxy, hydrogen, halogen, CN, and OH, and m, n, p, q and r are each independently selected from 0 and 1.

Preferably where R and R2 are alkyl or alkoxy, then they are C1 20, more preferably C3 12 and even more preferably C4 9.

Preferred compounds of Formula V are given below:

Bl B2 R2 C02R2 e Fe O\Zlla R' O2O J/ OR Fe /O2O

Typically, compounds of Formula V can be synthesised by preparation of 1,1'-alkylcarboxylic acids according to a method described by W F Little and R Eisenthal, 1960, J Am Chem Soc, 82, pal577, by Friedel-Crafts reaction of ferrocene with diphenylcarbamoyl chloride, followed by Friedel-Crafts acylation with an acid chloride.Subsequent reaction to give the appropriate R1 grouping can be achieved by eg reduction of the carbonyl group to give alkyl by means of triethylsilane in trifluoroacetic acid according to the method of C T West et al, 1973, J Org Chem, 38, p2675. Ester linking groups can be synthesised by eg reaction of a suitably substituted phenol with a ferrocenecarboxylic acid , benzoic acid or cyclohexanecarboxylic acid and dicyclohexylcarbodiimide with 4-(N-pyrrolidino)pyridine catalyst (see A Hassner and V Alexanian, 1978, Tetrahedron Lett, p4475).Schiffs base derivatives can be prepared using the method described in Malthete and Billard (supra). is all this relevant to the compounds of Formula V above? In another aspect of the invention the compounds of Formula V can be included in a liquid crystal material, where the liquid crystal material is a mixture of at least two compounds and contains at least one compound of Formula V.

In a further aspect of this invention compounds of Formula V and also liquid crystal materials described above can be incorporated in liquid crysatal devices. Such devices include electro-optical display devices and also devices which react to temperature, pressure and magnetic environment changes.

The invention will now be described by way of example only and with reference to figures 1 and 2, where figure 1 shows synthesis routes for compounds 1-22, and figure 2 shows synthesis routes for compounds 8, 9, 11, 23-34. All compound identification numbers given in bold type are made with reference to the appropriate reaction product as seen from the appropriate figure.

Individual reaction steps given in figures 1 and 2 are facilitated by the use of the following: Figure 1 (a) AlCl3/(C6H5)NCOCl (b) AlC13/RCOCl (c) ( C2H5 ) 3SiH/CF3CO2H (d) XOH/CH3OCH CH OH (e) DCC/4PP/R2OH Figure 2 (a) C8H17Br/K2C03/acetone (b) KOH/ethanol/water; acid (c) DCC/4PP/HOC6H,CHO (d) DCC/4PP/HOC6H4NO2 (e) H2/Pd (f) ethanol, heat.

The transition temperatures and natures of the phases were determined using an Olympus BH-2 polarising microscope fitted with a Mettler FP 52 heating stage and temperature controller. The transition temperatures were confirmed using a Perkin Elmer DSC-2C differential scanning calorimeter, calibrated with a pure indium sample. 1H nmr spectra were obtained using a JEOL JNMSX270 spectrometer, infrared spectra were obtained using a Perkin-Elmer 457 grating spectrophotometer and mass spectra were obtained using a Finnigan-MAT 1020 GC/MS spectrometer. The progress of reactions was monitored by thin layer chromatography (Merck, silica gel 60 F2s4 coated on aluminium sheets).Compounds were purified, where specified, by column chromatography using silica gel 60-120 mesh or by flash chromatography using Sorbsil C60 silica N,N-Diphenylcarbamoylferrocene (1) Powdered aluminium chloride (44.0 g, 32 mmol) was added to a cooled (0 OC), stirred solution of diphenylcarbamoyl chloride (622 g, 27 mmol) in dry l,2-dichloroethane (150 ml). A solution of ferrocene (50.0 g, 27 mmol) in dry 1,2-dichloroethane (350 ml) was added dropwise to the mixture during 1 hour. The reaction mixture was stirred and heated under reflux for a further 10 hours and allowed to cool.Water (150 ml) was added to the mixture and the organic layer was washed with 10% aqueous sodium hydroxide (100 ml) and then repeatedly with water (200 ml) until the aqueous washings were neutral. The organic layer was dried (MgSO4) and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (silica gel, dichloromethane;petroleum spirit (bp 4060 OC], 1:1). The eluent was changed to (dichloromethane:ethyl acetate, 10:1) after the unreacted ferrocene had been eluted and the product was obtained as orangeibrown crystals.

Yield 77.8 g, 76%; mp 178-179 CC; 1H n=(CDC13)o 4.17(d,2H), 4.19(d,2H), 4.25(s,5H), 7.24(m,6H), 7.35(m,4H); V cm-I 1732, 1645, 1600, 1490, 1445, 1340, 1270, 830, 765, 698; (mlz) 381(M+), 213(100%), 185, 129, 121.

1 -Buranoyl-1 '-NJN-diphenylcarbamoylferrocene (2) Powdered aluminium chloride (3.58 g, 26.2 mmol) was added to a cooled (0 C), stirred solution of compound 1 (5.0 g, 13.1 mmol) in dry 1,2-dichloroethane (50 ml). A solution of butanoyl chloride (1.4 g, 13.1 mmol) in dry 1,2-dichloroethane (20 ml) was added dropwise to the mixture during 1 hour. The reaction mixture was allowed to reach room temperature and stirred for a further 4 hours. Water (100 ml) was added to the mixture and the organic layer was washed with 10% aqueous sodium hydroxide (50 ml) and then repeatedly with water (150 ml) until the aqueous washings were neutral. The organic layer was dried (MgSO4) and the solvent was removed under reduced pressure.The crude product was purified by column chromatography (silica gel, dichloromethane) to give the product as an orange/brown semi-solid.

Yield 2.4 g, 40%; 1H nmr(CDC13)o 0.98(t,3H), 1.74(m,2H), 2.72(t,2H), 4.18(m,4H), 4.58(s,2H), 4.80(s,2H), 7.20(m,6H), 7.35(m,4H); umaX cm-l 2950, 2890, 1730, 1700, 1630, 1590, 1490, 1345, 1280, 835; (mlz) 451(M+), 283(100%), 213, 185, 167.

The following compounds were prepared by using a similar procedure to that described for compound 2.

1-Hexanoyl-1'-N,N-diphenylcarbarnoylferrocene (3) An orange-brown semi-solid from compound 1 and hexanoyl chloride; yield 15.6 g, 62%; 1H nmr(CDCl3)6 0.90(t,3H), 1.34(m,4H), 1.68(m,2H), 2.72(t,2H), 4.18(tt,4H), 4.57(t,2H), 4.80(t,2H), 7.25(m,6H), 7.36(m,4H); uglXax cm- 2950, 2890, 1730, 1705, 1635, 1600, 1495, 1348, 1290, 840; (mlz) 479(M+), 311(100%), 212, 184, 168.

1-Nonanoyl-1'-N,N-diphenylcarbamoylferrocene (4) An orange-brown semi-solid from compound 1 and octanoyl chloride; yield 14.3 g, 87%; 1H nmr(CDCl3)8 0.90(t,3H), 1.30(m,10H), 1.70(m,2H), 2.70(t,2H), 4.18(m,4H), 4.58(s,2H), 4.80(t,2H), 7.25(m,6H), 7.35(m,4H); uma, cm-l 2950, 2890, 1728, 1710, 1640, 1600, 1490, 1350, 1290, 830; (m/z) 521(M+), 353(100%), 212, 184, 168.

1-Butyl-1'-N,N-diphenylcarbamoylferrocene (5) Triethylsilane (1.33 g, 11.4 mmol) was added dropwise over 30 minutes to a cooled (0 C), stirred solution of compound 2 (2.36 g, 5.2 mmol) in trifluoroacetic acid (6.0 g, 52 mmol) and dry dichloromethane (150 ml). The reaction mixture was allowed to reach room temperature and stirred for a further 3 hours. Portions of saturated aqueous sodium bicarbonate solution were added carefully to the reaction mixture until the evolution of carbon dioxide had ceased The organic material was extracted into dichloromethane (2 x 50 ml) and the combined extracts were washed with water (2 x 50 ml) and dried (MgSO4). The solvent was removed under reduced pressure and the crude product was purified by column chromatography (silica gel, dichloromethane) to give an orange/brown oil.

Yield 1.23 g, 54%; 1H nmr(CDC13)6 0.90(t,3H), 1.45(m,4H), 2.28(t,2H), 4.20(m,8H), 7.22(rn,6H), 7.35(r44H); umaX cm- 2950, 2880, 1650, 1590, 1490, 1448, 1378, 1320, 1290, 760; (m/z) 437(M+), 268(100%), 212, 198, 167.

The following compounds were prepared by using a similar procedure to that described for compound 5.

I-Hexyl-l '-NJN-diphenylcarbamoylferrocene (6) An orange-brown semi-solid from compound 3; yield 3.75 g, 59%; 1H nmr(CDC13)6 0.90(t,3H), 1.32(m/6H), 1.50(m,2H), 2.35(t,2H), 4.08(m,4H), 4.12(t,2H), 4.15(t,2H), 7.23(m/6H), 7.34(m,4H); umax cm-l 2930, 2870, 1630, 1592, 1442, 1300, 1012, 830, 735, 695; (mlz) 465(M+), 297, 199, 167, 55(100%).

1-Nonyl-1'-NS '-N,N-phenykarbamoylferrocene (7) An orange-brown semi-solid from compound 4; yield 7.3 g, 53%; 1H nmr(CDCl3)# 0.90(t,3H), 1.27(m,12H), 1.50(m,2H), 2.35(tf2H), 4.08(m,4H), 4.14(m,4H), 7.22(m,6H), 7.35(m,4H); ')rnax cm-l 2930, 2870, 1648, 1595, 1495, 1448, 1380, 1302, 760, 700; (m/z) 507(M+,100%), 339, 199, 166, 120.

Ferrocenecarboxylic acid (8) Compound 1 (5.0 g, 13.1 mmol), was added to a homogeneous mixture of potassium hydroxide (6.0 g, 107 mmol) in 2-methoxyethanol (150 ml) and water (10 ml). The reaction mixture was heated under reflux for 24 hours, allowed to cool to room temperature and acidified with concentrated hydrochloric acid The organic material was extracted into ether (2 x 100 ml) and the combined ethereal extracts were washed with water (200 ml) and dried (MgSO4). The solvent was removed under reduced pressure and the crude acid was purified by column chromatography (silica gel, dichloromethane) to give brown crystals.

Yield 2.14 g, 71%; mp 205-206 OC; 1H nmr(CDC13)8 4.30(s,5H), 4.50(s,2H), 4.90(s,2H) the acid proton was not detected; #max cm- 3120-2560, 1660, 1480, 1402, 1285, 1160, 1035, 942, 838, 742; (mlz) 230(M+), 165, 138(100%), 73, 56.

The following compounds were prepared by using a similar procedure to that described for compound 8.

I '-Butylferrocene-l-carboxylic acid (9) Orange-brown crystals from compound 5; yield 0.52 g, 80%; mp 130-132 OC; 1H r (CDC13)o 0.90(t,3H), 1.40(m,4H), 25(m,2H), 425(s,4H), 4.50(s,2H), 4.85(s,2H), the acid proton was not detected; u,lkax cm- 3300-2500, 1668, 1480, 1298, 1162, 1030, 930, 820, 744; (mlz) 286(M+), 174, 165, 148, 81(100%).

I '-HeVlferrocene-l-carboxylic acid (10) Orange-brown crystals from compound 6; yield 0.85 g, 60%; mp 115-118 OC; 1H nmr(CDC13)o 0.90(t,3H), 1.26(m,6H), 1.45(m,2H), 2.26(t,2H), 4.14(s,4H), 4.43(s,2H), 4.80(s,2H), the acid proton was not detected; #max cm- 3100-2560,2940,2870, 1672, 1480, 1300, 1170, 1030, 828; (m/z) 314(M+, 100%), 243, 200, 165, 73.

l '-Nonylfrrrocene.1 -carboxylic acid (11) Orange-brown crystals from compound 7; yield 1.7 g, 62%; mp 61-62 OC; 1H nmr(CDCl3)# 0.90(t,3H), 1.30(m, 10H), 1.45(m,2H), 1.65(m,2H), 2.40(t,2H), 4.12(s,4H), 4.44(s,2H), 4.78(s,2H), the acid proton was not detected; ')max cm-1 3080,2930,2860, 1700, 1678, 1480, 1292, 1170, 1030, 820; (mlz) 356(M+,100%), 242, 165.

4-Heptyiphenyl 1'-butylferrocene-1-carboxylate (12) Dicyclohexylcaroodlmide (0.57 g, 2.8 mmol) and 4-(N-pyrrolidino)pyridine (0.1 g) were added to a stirred solution of compound 9(0.70 g, 2.5 mmol) and 4-heptylphenol (0.47 g, 25 mmol) in dry dichloromethane (50 ml). The reaction mixture was stirred at room temperature for 6 hours. The dicyclohexylurea was filtered off and the solvent from the filtrate was removed under reduced pressure.The crude product was purified by column chromatography (silica gel, dichloromethane) to give an orange/brown liquid Yield 1.05 g, 92%; 1H nmr(CDC13)6 0.90(2xt,6H), 1.34(m,10H), 1A8(m,2H), 1.64(m,2H), 2.32(t,2H), 2.62(t,2H), 4.20(s,4H), 4.45(s,2H), 4.90(s,2H), 7.08(d,2H), 7.20(d,2H); umaX Cm- 12960,2940, 1730, 1455, 1270, 1198, 1168, 1100, 1020, 912; (mlz) 460(M+), 269(100%), 192, 121, 107.

The following compounds were prepared by using a similar procedure to that described for compound 12.

4-Hexyioxyphenyl l' '-burylferrocene-I-carboxylare (13) An orange-red liquid from compound 9 and 4-hexyloxyphenol; yield 0.77 g, 87%; 1H nmr(CDC13)o 0.90(t,3H), 0.92(t,3H), 135(m,10H), 1.46(m,2H), 2.34(t,2H), 3.95(t,2H), 4.15(2xs,4H), 4.45(s,2H), 4.86(s,2H), 6.92(d,2H), 7.09(d,2H); #max cm-l 2930,2860, 1730, 1610, 1465, 1272, 1196, 1102, 1025,912; (m/z) 462(M+), 269(100%), 199, 121, 110.

4-(4-Pentyloxybenzoyloxy)phenyl '-butylferrocene-l-carboxylate (14) Orange crystals from compound 9 and 4-(4-pentyloxybenzoyloxy)phenol; yield 0.35 g, 90%; mp 76-77 C; 1H nmr(CDC13)8 0.90(t,3H), 0.95(t,3H), 1.35(m,2H), 1.45(m,6H), 1.84(m,2H), 2.35(t,2H), 4.05(t,2H), 4.18(s,4H), 4.47(s,2H), 4.88(s,2H), 6.98(d,2H), 7.25(2xs,4H), 8.15(d,2H); umaX cm-l 2930, 2860, 1738, 1720, 1610, 1455, 1260, 1134, 1108,1070; (m/z)568(M+), 268, 198, 191, 120(100%).

Biphenyl4-yl l'-hexylferrocene-1-carboxylate (15) Orange crystals from compound 10 and 4-hydroxybiphenyl; yield 0.25 g, 83%; mp 7273 C; 1H nmr(CDC13)o 0.90(t,3H), 1.28(m,6H), 1.46(m,2H), 2.80(t,2H), 4.24(s,4H), 4.48(s,2H), 4.94(s,2H), 7.24(d,2H), 7.35(d,2H), 7.35(m,1H), 7.45(t,2H), 7.59(d,2H), 7.62(d,2H); "max cm- 2920, 2850, 1716, 1480, 1448, 1265, 1200, 1165, 1100, 1005; (mlz)466(M+), 297(100%), 199, 141, 115.

4'-Bromobiphenyl4-yl l'-hexylferrocene-1-carboxylate (16) Orange crystals from compound 10 and 4-bromo-4'-hydroxybiphenyl; yield 0.28 g, 78%; mp 77-78 OC; 1H nmr(CDC13)8 0.86(t,3H), 1.30(m,6H), 1.49(m,2H), 2.32(t,2H), 4.19(m,4H), 4.46(s,2H), 4.90(s,2H), 7.26(d,2H), 7.45(d,2H), 7.57(d,2H), 7.59(d,2H); uma, cm- 2920, 2850, 1725, 1478, 1442, 1270, 1200, 1092, 1000, 830; (m/z) 545,544(M+), 465,464, 297(100%), 115.

4,4'-Di-(l'-hexylferrocene-1-carbonyloxy)biphenyl (17) Orange crystals from compound 10 and 4,4'-dihydroxybiphenyl; yield 0.15 g, 60%; mp 83-84 OC; 1H nmr(CDC13)6 0.88(t,6H), 1.30(m,12H), 1.50(m,4H), 2.35(t,4H), 4.20(s,8H), 4.46(s,4H), 4.90(s,4H), 7.26(d,4H), 7.64(d,4H); sumac cm- 2920, 2850, 1715, 1448, 1268, 1202, 1168, 1110; (mlz) 778(M+), 297(100%), 268, 227, 199.

4-(4-OctyiohenyIoxycarbonyi)phenyl l'-hexylferrocene-1-cartoxylate (18) Orange crystals from compound 10 and 4-(4-octyloxyphenyloxycarbonyl)phenol; yield 0.26 g, 85%; mp 53-54 OC; 1H nmr(CDC13)8 0.90(2xt,6H), 1.30(m,12H), 1.48(m,4H), 1.75(m,2H), 1.92(m,2H), 2.32(t,2H), 3.96(t,2H), 4.20(s,4H), 4.49(s,2H), 4.90(s,2H), 6.94(d,2H), 7.12(d,2H), 7.35(d,2H), 7.37(d,2H); #max cm- 2920, 2840, 1720, 1600, 1502, 1450, 1262, 1186, 1156, 1062; (mlz) 638(M+), 297(100%), 199, 121.

4-[(4'-Octyloxybiphenyl-4-yl)oxycarbonyl]phenyl l'-hexylferrocene-l-carboxylate (19) Orange crystals from compound 10 and 4-t(4'-octyloxybiphenyl-4- yl)oxycarbonyl]phenol; yield 0.28 g, 82%; transitions K 107 (N 63) I; 1H nmr(CDC13)o 0.90(2xt,6H), 1.30(m,12H), 1.48(m,4H), 1.75(m,2H), 1.92(m,2H), 2.34(t,2H), 4.00(t,2H), 4.20(s,4H), 4.48(s,2H), 4.90(s,2H), 6.94(d,2H), 726(d,2H), 7.35(d,2H), 7.52(d,2H), 7.60(d,2H), 8.30(d,2H); umaX cm-1 2920, 2845, 1730, 1718, 1492, 1268, 1208, 1160, 1070 (mlz) 714(M"), 297(100%), 121.

4'-Cyanobiphenyl4-yl I '-nonylferrocene-I-carboxylate (20) Orange crystals from compound 11 and 4cyano-4'-hydroxybiphenyl; yield 0.62 g, 84%; mp 77-78 OC; 1H nmr(CDC13)8 0.85(t,3H), 1.24(m,10H), 1.48(m,2H), 2.32(t,2H), 4.18(d,4H), 4.46(t,2H), 4.90(t,2H),7.31(d,2H), 7.65(d,2H), 7.68(d,2H), 7.76(d,2H); #max cm- 2930, 2860, 2230, 1725, 1610, 1550, 1458, 1280, 1205, 1110; (mlz) 533(M+), 339(100%), 239, 199, 121.

4 '-Decyloxybiphenyl-4-y1 l'-nonylferrocene-l-carboxylate (21) Orange crystals from compound 11 and 4-hydroxy-4'-decyloxybiphenyl; yield 0.86 g, 93%; mp 66-67 OC; 1H nmr(CDC13)S 0.88(2xt,6H), 1.28(m,24H), 1.45(m,4H), 1.70(m,2H), 2.12(m,2H), 4.00(t,2H), 4.60(m,6H), 5.12(m,2H), 6.96(d,2H), 7.16(d,2H), 7.52(2xd,4H); ')rnax cm-1 2930,2860, 1732, 1612, 1502, 1280, 1210, 1172, 1104, 838; (mlz) 664(M+), 339, 199, 185, 57(100%).

1,4-Di-(l'-nonylferrocene-1-carbonyloxy)benzene (22) Orange crystals from compound 11 and hydroquinone; yield 0.36 g, 75%; mp 34-36 C; 1H nmr(CDC13)8 0.90(t,6H), 128(m,24H), 1.50(m,4H), 2.34(m,4H), 4.18(m,8H), 4.45(s,4H), 4.88(s,4H), 7.24(s,4H); #max cool 2930, 2860, 1730, 1505, 1452, 1380, 1275, 1188, 1102, 835; (mlz) 786(M+), 588, 339, 198, 140(100%).

4-Nitrophenylferrocenecarboxylate (23) Orange crystals from compound 8 and 4-nitrophenol; yield 1.98 g, 98%; mp 142-143 OC; 1H nmr(CDC13)S 4.30(s,5H), 4.56(s,2H), 4.98(s,2H), 7.40(ds2H), 8.30(d,2H); Vmax cm- 1740, 1598, 1518, 1450, 1342, 1210, 1090, 1022, 912, 760; (mlz) 351(M+,100%), 213, 185.

4-Nitrophenyl l'-burylferrocene-l-carboxylate (24) Orange crystals from compound 9 and 4-nitrophenol; yield 1.2 g, 85%; mp 128-129 OC; 1H nmr(CDC13)o 0.90(t,3H), 1.32(m,2H), 1.50(m,2H), 2.30(t,2H), 4.20(s,4H), 4.50(s,2H), 4.90(s,2H), 7.40(d,2H), 8.30(d,2H); Vmax cm- 2930, 2860, 1740, 1599, 1520, 1450, 1345, 1210, 1090, 860; (mlz) 407(M+,100%), 269.

4-Nitrophenyl l'-nonylferrocene-l-carboxylate (25) Orange crystals from compound 11 and 4-nitrophenol; yield 1.25 g, 93%; mp 110-111 OC; 1H nmr(CDC13)6 0.88(t;3H), 1.28(m,12H), 1.50(m,2H), 2.30(t,2H), 4.18(s,4H), 4.50(s,2H), 4.88(s,2H), 7.40(d,2H), 8.32(d,2H); #max cm-l 2930, 2860, 1740, 1598, 1526, 1452, 1348, 1208, 1090, 862; (mlz) 477(M+,100%), 339.

4-Aminophenylferrocenecarboxylate (26) A stirred solution of compound 23(1.8 g, 5.1 mmol) in ThF (80 ml) was hydrogenated over a palladium/charcoal catalyst. After the calculated volume of hydrogen had been taken up the catalyst was filtered off (Hyflo Supercel) and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (silica gel, dichloromethane) to give orange crystals.

Yield 0.63 g, 38%; mp 151-152 OC; 1H nmr(C:DC13)8 3.35(s,2H), 4.30(s,5H), 4.48(s,2H), 4.95(s,2H), 6.75(d,2H), 7.00(d,2H); #maxcm- cm- 3380, 3350, 1715, 1620, 1510, 1452, 1280, 1195, 1116, 825; (mlz) 321(M+), 114, 80, 69, 54(100%).

The following compounds were prepared by using a similar procedure to that described for compound 26.

4 -Arninophenyl l'-burylferrocene-l-carboxylate (27) Orange oil from compound 24; yield 0.76 g, 68%; 1H nmr(CDC13)6 0.90(t,3H), 1.34(m,2H), 1.45(m,2H), 2.34(t,2H), 3.65(s,2H), 4.15(s,4H), 4.42(s,2H), 4.85(s,2H), 6.70(d,2H), 6.96(d,2H); #max cm-l 3460,3370,2940, 1720, 1630, 1515, 1455, 1275, 1196, 1110; (m/z) 377(M+,100%), 269, 199, 108.

4 -Arninop henyl I -nonylferrocene4 -carboxylate (28) Orange oil from compound 25; yield 0.70 g, 70%; 1H nmr(CDCl3)# 0.89(t,3H), 1.26(m,12H), 1.49(m,2H), 2.33(t,2H), 3.65(s,2H), 4.16(s,4H), 4.42(s,2H), 4.85(s,2H), 6.72(d,2H), 7.12(d,2H); umaX cm-l 3960,3380,2930,2860, 1720, 1630, 1517, 1452, 1196, 1110; (mlz) 447(M+,100%), 339, 108.

Methyl 4-octyloxybenzoate (29) A solution of l-bromooctane (22.9 g, 118.4 mmol) in acetone (50 ml) was added dropwise during 1 hour to a vigorously stirred mixture of methyl 4-hydroxybenzoate (15.0 g, 98 mmol) and potassium carbonate (27.3 g, 197 mmol) in acetone (300 ml). The mixture was heated under reflux for 72 hours and allowed to cool to room temperature. The organic material was extracted into.etlier (2 x 300 ml) and the combined ethereal extracts were washed with water (400 ml) and dried (MgSO4). The solvent was removed under reduced pressure and the crude product was purified by column chromatography (silica gel, dichloromethane:petroleum spirit [bp 40-60 C], 1:1) to give colourless crystals.

Yield 7.06 g, 27%; mp 35-36 OC; 1H nmr(CDC13)6 0.90(t,3H), 1.30(m,8H), 1.45(m,2H), 1.80(m,28), 3.88(s,3H), 4.00(t,2H), 6.90(d,2H), 7.96(d,2H); #max cm-l 2920, 2860, 1730, 1612, 1440, 1288, 1258, 1172, 1112, 850; (mlz) 264(M+,100%), 152, 121, 113.

4-Octyloxybenzoic acid (30) Compound 29 (5.0 g, 19 mmol) was added to a homogeneous mixture of potassium hydroxide (1.10 g, 19.6 mmol) in ethanol (100 ml) and water (10 ml) and the reaction mixture was heated under reflux for 8 hours. The reaction mixture was allowed to cool to room temperature and the excess of ethanol was removed under reduced pressure. The salt of the required acid was taken up in water (200 ml) and washed with ether (100 ml). The aqueous layer was acidified with sulphuric acid and the resulting precipitate was filtered off and washed with water. The crude product was purified by recrystallisation (petroleum spirit [bp 40-60 OCI) to give colourless needles.

Yield 4.6 g, 97%; transitions ( C) K 101 5c 108 SA 143 I; 1H nmr(CDC13)6 0.90(t,3H), 1.30(m,8H), 1.45(m,2H), 1.80(m,2H), 4.02(t,2H), 6.95(d,2H), 8.05(d,2H), 12.15(s,1H); #max cm- 2930, 2850, 2600, 1690, 1610, 1430, 1252, 1170, 930, 850; (m/z) 250(M+), 138, 71, 57, 43(100%).

4-(4-Octyloxybenzoylaxy)benzaldehyde (31) This compound was prepared as colourless crystals from compound 30 and 4 hydroxybenzaldehyde by using a similar procedure to that described for compound 12. Yield 393 g, 92%; transitions ( C) K 56 N 126 I; 1H n=(CDC13)o 0.90(t,3H), 1.34(m,8H), 10(m,2H), 1.85(m , 4.05(t,2H), 6.98(d,2H), 7.40(d,2H), 7.95(d,2H), 8.12(d,2H), 10.02(s,1H); #max crsl 2935, 2855, 1735, 1704, 1608, 1516, 1270, 1218, 1170, 1075; (m/z) 354(M+), 233(100%), 120, 93.

l-(Ferrocenecarbonyloxy)-4-[4-(4-octyloxybenzoyloxy)benzylideneanuno]benzene (32) A mixture of compound 31 (0.57 g, 1.6 mmol) and compound 26 (0.52 g, 1.6 mmol) in ethanol was heated under reflux for 10 hours. The mixture was allowed to cool and the product crystallised as orange plates. The precipitate was filtered off and recrystallised (ethanol).

Yield 0.68 g, 55%; transitions ( C) K 154 N 168 1; 1H nmr(CDC13)8 0.90(t,3H), 1.34(m,8H), 1.48(m,2H), 1.85(m,2H), 4.05(t,2H), 4.30(m,5H), 4.50(m,2H), 4.98(rn,2H), 7.00(d,2H), 7.22(d,2H), 7.30(d,2H), 7.36(d,2H), 8.00(d,2H), 8.15(d,2H), 8.50(s,1H); 1 #max cm-I 2930, 2860, 1730, 1610, 1512, 1260, 1195, 1168, 1102, 1060; (m/z) 657(M+), 520, 393, 321(100%), 213.

The following compounds were prepared by using a similar procedure to that described for compound 32.

1-(1'-Bulylferrocene-1-carbonyloxy)-4-[4(4-octylaxybenzoyloxy)benzylidenearnino]- benzene (33) Orange plates from compounds 31 and 27; yield 0.71 g, 50%; transitions ( C) K 96 N 127 I; 1H nmr(CDC13)8 0.90(t,6H), 1.30(m,10H), 1.48(m,4H), 1.84(m,2H), 2.35(t,2H), 4.05(t,2H), 4.18(m,4H), 4.46(s,2H), 4.90(s,2H), 7.08(d,2H), 7.25(d,2H), 7.30(d,2H), 7.36(d,2H), 7.95(d,2H), 8.16(d,2H), 8.60(s,1H); X #max cm-1 2930, 2860, 1730, 1720, 1604, 1510, 1260, 1195, 1102, 1060; (mlz) 713(M+), 268, 233, 199, 121(100%).

1-(1 '-Nonylferrocene-1-carbonyloxy-4-[4-(4-octyloxybenzoyloxy)benzylideneamino]- benzene (34) Orange plates from compounds 31 and 28; yield 0.57 g, 52%; transitions ( C) K 83 N 115 I; 1H nmr(CDC13)o 0.90(tt,6H0, 1.30(m,20H), 1.46(m,4H), 1.82(m,2H), 2.34(t,2H), 4.05(t,2H), 4.20(m,4H), 4.45(s,2H), 4.90(s,2H), 6.97 (d,2H), 7.25(d,2H), 7.30(d,2H), 7.35(d,2H), 7.95(d,2H), 8.15(d,2H), 8.60(s,1H); #max cm- 2930, 2860, 1730, 1720, 1610, 1512, 1260, 1195, 1165, 1060; (m/z) 783(M+), 712, 552, 446, 356(100%).

The transition temperatures for the ferrocene are given below in Table 1. 1 ] indicates that the transition is a virtual transition temperature determined by miscibility with 135, except compound 20 for which cyano-host E7 was used, where both hosts were supplied by Merck Ltd, West Quay Road, Poole, Dorset, BH15 1HX. ( ) indicates a monotropic transition.

Compound Transition Temperatures 12 Liquid 13 Liquid 14 K 77 I 15 K 73 N (-85] I 16 K 78 N (-20] I 17 K 84 N (-28] I 18 K 54 N (-6] 1 19 K 107 (N 63) I 20 K 78 N (-25] I 21 K 67 I 22 K 35 I 32 K 153 N 167 I 33 K 96 N 127 I 34 K 83 N 115 I TABLE 1.

Claims (12)

CLAIMS.

1 A ferrocene compounds characterised by Formula V:

Formula V wherein R1 is selected from alkyl, alkoxy, hydrogen, halogen, and CN, and R2 is (A1-Z1) (A2-Z2)n (A3,Z3) (A4-Z4)q (R3) Formula VI where each of At, A2, A3 and A4 are independently selected from CO2, O2C, N=CH, HC=N and a single bond, Z1, Z2. Z3 and Z4 are independently selected from 1,4 phenylene, and ferrocene, R3 is selected from alkyl, alkoxy, hydrogen, halogen, CN, and OH, and m, n, p, q and r are each independently selected from 0 and 1.

2 A compound according to claim 1 where R1 is selected from H and C1-20 alkyl.

3 A compound according to claim 2 where At is a single bond.

4 A compound according to claim 3 where q is 0.

5 A compound according to claim 4 where one of Z1, Z2 and Z3 is selected as ferroecene.

6 A compound according to claim 4 where (m+n+p) is 2 or 3.

7 A compound according to claim 6 where each of A2 and A3 is a single bond.

8 A compound according to claim 6 where r is 0.

9 A compound according to claim 6 where at least one of A2 and A3 is selected from CO2 and 02C.

10 A compound according to claim 9 where (m+n+p) is 3, one of A2 and A3 is selected from CO2 and 02C, and one of A2 and A3 is selected from N=HC.

11 A liquid crystalline material, being a mixture of at least two compounds, characterised in that at least one compound is a compound of Formula V.

12 A liquid crystal device in characterised in that it contains a material according to claim 11.