J O U R N A L O F C H E M I S T R Y Materials Discotic liquid crystals of transition metal complexes. Part 24† Synthesis and mesomorphism of porphyrin derivatives substituted with two or four bulky groups Kazuchika Ohta,* Noboru Yamaguchi and Iwao Yamamoto Department of Functional Polymer Science, Faculty of Textile Science and Technology, Shinshu University, 386–8567 Ueda, Japan. E-mail: ko52517@giptc.shinshu-u.ac.jp Received 21st July 1998, Accepted 2nd September 1998 We have synthesized nine novel porphyrin derivatives, 1–8 and 1-Cu, substituted with various steric hindrance groups and long flexible chains in order to investigate the relationship between the molecular type of porphyrin derivatives and the resulting mesophase.Type 4 disc-like (C12O)16-TTPH2 (1) and (C12O)16-TTPCu (1-Cu) derivatives exhibit Dh columnar mesophases, which are the first examples of meso-substituted porphyrin metal-free derivatives and copper complexes.Type 5 strip-like (CnO)8-BTPH2 [4 (n=12), 5 (n=16)] derivatives having eight long chains at the 5,15-positions exhibit Drd columnar mesophases. On the other hand, the type 5 (C12O)4-BTPH2 (6) derivative having four long chains exhibits discotic lamellar DL.rec1 and DL.rec2 mesophases which have a twodimensional rectangular structure within the layer.The (C12O)4-BPPH2 (7) type 6 derivative also shows a DL lamellar mesophase. Bruce et al. reported that type 3 rod-like porphyrin derivatives show calamitic mesophases of SB, SE and SE¾ phases. We revealed from these types of mesogenic porphyrin derivatives that such a successive change of the molecular structures causes their mesophases to change from discotic columnar to discotic lamellar, and further to calamitic. 1.Introduction Porphyrins and their analogues exist in various states in nature and act as centers of energy transfer and charge transfer processes. In order to reveal their mechanistic role in natural systems, a number of porphyrin derivatives have been synthesized and studied extensively as models of vital functions.2,3 Moreover, porphyrins are expected to find applications in functional materials because of their favorable electronic properties, chemical and thermal stabilities.For the eVective utilization of functionalities of a certain molecule, it is important to control the electronic and steric environments and the state of aggregation of the molecules.For this purpose, the following methods have been used: (a) enlargement of the p-conjugated system,4 (b) giving molecular recognizability by modification of the molecule with bulky substituent,3 and (c) formation of aggregates such as membranes, micelles, or microemulsions by introduction of aliphatic, hydrophilic, or amphiphilic substituents.5 It may be very useful to incorporate liquid crystallinity to organic metal complexes with various valuable characteristics, in order to provide new properties or to modify known properties of the original complexes.For example, it was reported that the third-order nonlinear optical susceptibility (x(3)) of tetrakis- (octylthio)phthalocyaninatocopper(II) in the mesomorphic state is larger than that in the solid state.6 The first study of mesogenic porphyrins was reported in 1980 for uroporphyrin I octa-n-dodecyl ester which shows a monotropic discotic mesophase.7 Since then, some mesogenic porphyrins have been synthesized and their mesomorphic properties investigated,8–17 although there are fewer mesogenic porphyrins than mesogenic phthalocyanines18 whose core shape is very analogous to porphyrin.Most of the mesogenic porphyrins have been synthesized mainly from the photophysical viewpoint. Liquid crystals containing the porphyrin core reported to date can be classified into three types by means of their molecular shapes (see Fig. 1). Type 1 consists of the b- N N N N R M R R R N N N N R M R R R R R R R N N N N M R R (Type 3) (Type 2) (Type 1) Fig. 1 Three types of mesogenic porphyrin derivatives reported to date. †Part 23: Ref. 1. J. Mater. Chem., 1998, 8, 2637–2650 2637substituted porphyrin derivatives. Greg et al. synthesized many octakis-substituted porphyrin derivatives which exhibit a discotic columnar mesophase.8,9 Octakis(alkoxyethyl )porphyrinatozinc( II) was investigated in terms of the photovoltaic eVect9 and radiation-induced conductivity.10 It was reported by Doppelt11 and Morelli et al.12 that octakis(octylthio)tetraazaporphyrin metal complexes show a discotic hexagonal columnar (Dh) mesophase.The compounds of this type tend to form a columnar mesophase in which the molecules stack one-dimensionally because of the flatness of the molecule.Type 2 is the meso-substituted porphyrin derivatives. Shimizu et al. synthesized a series of tetra-(long-alkyl chain)-substituted tetraphenylporphyrins and reported that they exhibit a discotic lamellar (DL) mesophase.13 They characterized several properties such as photoconductivity,14 third-order nonlinear optical susceptibility,15 and so on. Besides, some long chain esters of meso-tetrakis(p-carboxyphenyl )porphyrin were reported to exhibit an identified phase with a lamellar structure.16 From these examples mentioned above, compounds of type 2 show not a columnar mesophase but a lamellar mesophase because van der Waals interaction between the porphyrin macrocycles have been weakened by the existence of bulky groups (phenyl groups) near the porphyrin core, and because the small number of flexible chains around the core are not enough to occupy all the surrounding area to form a columnar structure.On the other hand, it was reported by Bruce et al. that 5,15- bis(p-alkoxyphenyl )porphyrinatozinc(II), belonging to type 3, shows smectic B, E, and E¾ phases (abbreviated as SB, SE and SE¾, respectively).17 It is interesting that this porphyrin, the molecular shape of which is basically discotic (disk-like), shows not discotic columnar mesophases but calamitic mesophases, although long-chain-substituted disk-like compounds generally tend to show columnar mesophases.We noticed that the porphyrin derivatives could more easily change their molecular shapes compared with other macrocyclic compounds such as phthalocyanines.From this synthetic viewpoint, a great variety of mesogenic porphyrin derivatives will be able to be obtained. In order to study how the mesomorphism may change with changing the kind of bulky group and/or the number of flexible long alkyl chains in the surroundings of a porpyrin core, we have synthesized nine novel porphyrin derivatives of four types, 1–8 and 1-Cu, as illustrated in Fig. 2, and investigated their mesomorphism. Compounds 1–3 have four o-terphenyl groups with long alkoxy chains at the 5, 10, 15 and 20-positions of the porphyrin, and they are abbreviated as (CnO)m-TTPM (n=8, 12; m=8, 16; M=H2, Cu). Compounds 4–6 have two of the o-terphenyl groups replaced by two o-terphenyl groups with long alkoxy chains at the 5 and 15-positions, and abbreviated as (CnO)m- BTPM (n=12, 16; m=4, 8).Compounds 7 and 8 are 5,15- bis(3,4-didodecyloxyphenyl )porphyrin [abbreviated as (C12O)4-BPPH2] and 5,15-bis(4-dodecyloxybiphenyl )porphyrin [abbreviated as (C12O)2-BBPH2], respectively. Although compounds 1–3 are similar to type 2, the number of the long chains attached to them are two or four times as many as those of type 2.These compounds are, therefore, classified as type 4. Compounds 4–6 have the structure in which the number of o-terphenyl moieties is halved compared with type 4, so that they are referred to as type 5. Compound 7 is classified as type 6, because the number of alkoxy long chains is twice those of conventional type 3. Compound 8 belongs to 1: R1=R2=C12H25O, M=H2; (C12O)16-TTPH2 1-Cu : R1=R2=C12H25O, M=Cu; (C12O)16-TTPCu 2: R1=R2=C8H17O, M=H2; (C8O)16-TTPH2 3: R1=C12H25O, R2=H, M=H2; (C12O)8-TTPH2 M N N N N R1 R1 R1 R2 R1 R2 R1 R2 R1 R2 R2 R1 R2 R1 R2 R2 (Type 5) 4: R1=R2=C12H25O; (C12O)8-BTPH2 5: R1=R2=C16H33O; (C16O)8-BTPH2 6: R1=C12H25O, R2=H; (C12O)4-BTPH2 NH N N HN R2 R1 R2 R1 R2 R1 R2 R1 (Type 6) 7: (C12O)4-BPPH2 NH N HN N C12H25O C12H25O OC12H25 OC12H25 (Type 3) 8: (C12O)2-BBPH2 NH N N HN C12H25O OC12H25 (Type 4) type 3.Fig. 2 Formulae of the porphyrin derivatives in this work. We wish to report here that such a successive change of the molecular structures causes their mesophases to change from In Scheme 1, the syntheses of alkoxybenzils (13) from the discotic columnar to discotic lamellar, and further to calamitic.starting materials (9) were carried out by the method of Wenz.19 In Scheme 2, 3,4-didodecyloxybenzaldehyde (19) was prepared by the method of Strzelecka et al.20 4-Bromo-4¾- 2. Results and discussion dodecyloxybiphenyl (21) was synthesized according to the 2-1. Synthesis procedure described by Gray et al.21 The syntheses of tetrakissubstituted porphyrin derivatives 1–3 (Scheme 3) followed the The porphyrin derivatives 1–8 in this work have been synthesized by using synthetic routes as shown in Scheme 1–4. conventional method described by Adler et al.,22 and these 2638 J.Mater. Chem., 1998, 8, 2637–2650MeO MeO O OH X CHO X X OMe O MeO X X O OMe Y HO O Y OH O R2 R1 R2 R1 O O R2 R1 R2 HO O R1 10 KCN 9a; X=OMe 9b; X=H 11 12 13 14 Pyridine CuSO4•5H2O AcOH HBr K2CO3 RBr ButOK p-TosOH 12a; Y=OH 12b; Y=H 13a; R1=R2=C12H25O 13b; R1=R2=C8H17O 13c; R1=R2=C16H33O 13d; R1=C12H25O, R2=H HC C CO2Me O R2 R1 R2 R1 CO2Me 15 R2 R1 R2 R1 CH2OH R2 R1 R2 R1 CHO 16 PDC 17 LiAlH4 Scheme 1 Synthetic route to aldehyde 17. 2-2. Liquid crystalline properties 2-2-1. (CnO)m-TTPM (1, 1-Cu, 2 and 3, type 4). Phase transition temperatures and enthalpy changes of (C12O)16- TTPH2 (1), (C12O)16-TTPCu (1-Cu), (C8O)16-TTPH2 (2) and (C12O)8-TTPH2 (3) are summarized in Table 3.(C12O)16- TTPH2 (1) and (C12O)16-TTPCu (1-Cu) exhibit mesomorphism in the low-temperature region. The DSC thermograms of (C12O)16-TTPH2 (1) were very complicated. When the pristine sample of this compound was at first cooled to ca. -100 °C and then heated at 10 °Cmin-1, we observed a very broad endothermic peak corresponding to the transition from the X1 phase to the M1 phase at ca.-80 °C and a comparatively large endothermic peak corresponding to the change from the M1 phase to the isotropic liquid (IL) at 39 °C. In addition, a small endothermic peak which overlapped with the peak at 39 °C was observed at 59 °C. This peak corresponds to the clearing point of the M2 phase.When this IL was once more cooled to ca. -100 °C HO HO CHO C12H25O C12H25O CHO C12H25O CHO C12H25O Br Br HO 1) BunLi 2) DMF C12H25Br KOH/EtOH 19 18 KOH, Aliquat 336 C12H25Br 20 21 22 and heated, a new broad endothermic peak appeared at ca. Scheme 2 Synthetic routes to aldehydes 19 and 22. -35 °C. This peak corresponds to the transition from the X2 phase to the M2 phase.Besides, a comparatively small peak corresponding to the X1–M1 transition at ca. -80 °C was also observed. This result indicates that when the IL of this resulting by-products, namely, chlorine derivatives were oxidcompound is cooled, it changes into not only the X2 phase ized as described in the literature.23 The copper complex (1- but also the X1 phase to some degree. On further heating, a Cu) of metal free derivative 1 was obtained by the conventional small endothermic peak near 39 °C appeared, followed by a synthetic procedure.24 Bis-substituted porphyrin derivatives broad exothermic peak due to relaxation from the IL to the 4–8 (Scheme 4) were synthesized by using the method of M2 phase, and a small endothermic peak due to clearing from Manka et al.25 Further details of these synthetic procedures the M2 phase to the IL was finally observed at 59 °C.The will be described in the Experimental section. thermogram areas of the M–IL transition varied with the non- Elemental analysis data of the porphyrin derivatives 1–8 virgin samples and their enthalpy changes were below one- are summarized in Table 1. Electronic absorption spectral data tenth of that of the pristine sample.This result indicates that for all of the porphyrin derivatives in this work are presented when a sample cleared to the IL is cooled, most of the sample in Table 2. Each of the electronic absorption spectra showed remains in a supercooled liquid state because of the low Soret- and Q-bands which are characteristic bands of porphyrin compounds.cohesivity of these molecules. Relaxation of this supercooled J. Mater. Chem., 1998, 8, 2637–2650 2639DMF CuCl2 C2H5CO2H DDQ (C12O)16-TTPH2 (C12O)16-TTPCu NH N HN N NH R1 R1 R1 R2 R1 R2 R1 R2 R1 R2 R2 R1 R2 R1 R2 R2 R2 R1 R2 R1 CHO 1: R1=R2=C12H25O; (C12O)16-TTPH2 2: R1=R2=C8H17O; (C8O)16-TTPH2 3: R1=C12H25O, R2=H; (C12O)8-TTPH2 17 1 Cu–1 Scheme 3 Syntheses of the porphyrin derivatives 1–3 and the copper(II) complex of 1 (1-Cu). 4: R1=R2=C12H25O; (C12O)8-BTPH2 5: R1=R2=C16H33O; (C16O)8-BTPH2 6: R1=C12H25O, R2=H; (C12O)4-BTPH2 1) , CF3CO2H 2) Chroranil , CF3CO2H 1) , CF3CO2H 2) Chroranil R1 R2 R1 R2 R1 R2 R1 R2 R2 R1 R2 R1 CHO NH N HN N HN NH C12H25O C12H25O CHO NH HN NH N HN N C12H25O C12H25O OC12H25 OC12H25 C12H25O CHO NH HN C12H25O NH N HN N OC12H25 17 1) 19 7: (C12O)4-BPPH2 2) Chroranil 22 8: (C12O)2-BBPH2 Scheme 4 Syntheses of the porphyrin derivatives 4–8. 2640 J. Mater. Chem., 1998, 8, 2637–2650Table 1 Elemental analysis data of the porphyrin derivatives in this work Found% (Calc.%) Molecular formula Compound (molecular weight) C H N C284H446N4O16 81.81(81.75) 10.89(10.77) 1.18(1.34) (C12O)16-TTPH2 (1) (4172.72) C284H444N4O16Cu 80.26(80.56) 10.40(10.57) 1.16(1.32) (C12O)16-TTPCu (1-Cu) (4234.21) C220H318N4O16 80.72(80.69) 9.80(9.79) 1.55(1.71) (C8O)16-TTPH2 (2) (3274.99) C188H254N4O8 83.78(83.69) 9.46(9.49) 1.99(2.08) (C12O)8-TTPH2 (3) (2698.13) C152H230N4O8 81.72(81.45) 10.36(10.34) 2.38(2.50) (C12O)8-BTPH2 (4) (2241.54) C184H294N4O8 81.94(82.15) 10.81(11.02) 1.94(2.08) (C16O)8-BTPH2 (5) (2690.38) C104H134N4O4 82.70(83.04) 8.82(8.98) 3.55(3.73) (C12O)4-BTPH2 (6) (1504.23) C80H118N4O4 80.17(80.08) 9.94(9.91) 4.26(4.67) (C12O)4-BPPH2 (7) (1199.85) C68H78N4O2 83.19(83.05) 7.99(8.00) 5.74(5.70) (C12O)2-BBPH2 (8) (983.39) liquid into the M1 phase is extremely slow; the non-pristine 9.55 A° , is twice the ordinary stacking distance, 3.5–4.7 A° , for columnar mesophases, so that it may be an interdimer distance. sample kept at room temperature (r.t.) for more than one year exhibited the same thermal behavior as the pristine sample.In this mesophase, dimerization may occur. We have calculated the number of molecules, Z, in the Considering from the results described above, the pristine state of this compound is the M1 phase at room temperature and two-dimensional hexagonal lattice with the possible interdimer distance h (a=41.5 A° , h=9.55 A° ) by the following equation: when it is cooled below ca.-80 °C it changes into the X1 phase. When it is heated, double clearing behavior of Z=rVL/M M1AIL—(relaxation)AM2AIL occurs. The X2 phase in the where r is the density; V, the unit cell volume; L, Avogadro’s non-pristine sample, which does not exist in the pristine number; and M, the molecular weight.Generally, it is con- sample, is obtained by cooling. However, the X1 and X2 phases sidered that the density of a compound in the liquid crystalline are mingled to some extent in the non-pristine sample which state is 0.9–1.0 g cm-3. Thereby, the density r of the present shows, as a result, more complicated phase transition behavior.compound 1 in the mesophase at 125 °C is assumed as Identification of each of the phases in the (C12O)16-TTPH2 1 g cm-3. (1) derivative was carried out by X-ray diVraction measurements and observation of the optical textures. However, the V=(Ó3/2)a2h X1 and X2 phases could not be identified because these two =(Ó3/2)×45.12×9.55 A° 3 phases exist in a very low temperature region beyond the range of our instrumental techniques. The M1 phase could be =1.42×10-20 cm-3 identified by using the pristine sample at r.t., and the M2 Z=1×1.42×10-20×6.02×1023/4172.72 phase could be also identified by using a sample prepared by annealing the supercooled liquid for 10 days between 39 °C =2.05 (clearing point of the M1 phase) and 59 °C (clearing point of theM2 phase).As summarized in Table 4, the X-ray diVraction Thus, we could confirm that two molecules exist in the unit cell. This means that the dimers stack with a periodicity of pattern of the M1 phase of (C12O)16-TTPH2 (1) at r.t. gave two narrow peaks in the low angle region, a fairly sharp peak 9.55 A° in the column. Hence, this phase could be assigned as a discotic hexagonal ordered columnar (Dho) mesophase.in the medium angle region, and a broad halo around 2h= 20° at wide angles. The spacing ratio of the first two, low- When this sample was heated to 55 °C and then annealed at this temperature overnight to make the M2 phase, the X-ray angle peaks was 15(1/Ó3), which is a characteristic of twodimensional hexagonal packing.The halo around 2h=20° diVraction pattern showed two reflections in the low angle region, a very broad and weak halo in middle angle region, corresponds to the melting of the alkoxy chains. The fairly sharp peak in the medium angle region may correspond to a and a broad and big halo around 2h=20° in the wide angle region. From the spacing ratio of the first peaks in the low stacking distance in the columnar structure.The spacing, Table 2 Electronic absorption spectral data of the porphyrin derivatives in chloroform lmax/nm( log e) Concentration/ Compound 10-6 mol l-1 Soret band Q band (C12O)16-TTPH2 (1) 5.92 426.9(5.71) 520.4(4.32), 557.2(4.18), 594.0(3.82), 649.8(3.85) (C12O)16-TTPCu (1-Cu) 6.10 422.4(5.71) 541.6(4.42), 579.0(3.75) (C8O)16-TTPH2 (2) 6.23 426.9(5.68) 520.4(4.28), 557.1(4.15), 594.2(3.77), 650.4(3.80) (C12O)8-TTPH2 (3) 6.45 426.6(5.69), 462.3(4.46) 519.7(4.27), 556.9(4.17), 594.2(3.83), 650.7(3.92), 678.4(3.92) (C12O)8-BTPH2 (4) 5.36 412.7(5.46) 505.6(4.17), 542.4(4.07), 578.0(3.83), 632.5(3.49) (C16O)8-BTPH2 (5) 6.18 411.8(5.51) 504.9(4.27), 540.2(4.04), 576.4(3.86), 631.7(3.62) (C12O)4-BTPH2 (6) 6.56 411.7(5.58) 504.6(4.25), 540.5(3.98), 576.7(3.78), 631.7(3.48) (C12O)4-BPPH2 (7) 5.58 412.5(5.58), 443.2(sh, 4.27) 504.9(4.30), 542.2(4.19), 580.4(4.06), 636.2(3.78) (C12O)2-BBPH2 (8) 6.48 411.4(5.59) 504.7(4.23), 540.0(3.97), 577.5(3.73), 631.9(3.36) J.Mater. Chem., 1998, 8, 2637–2650 2641Table 3 Phase transition temperatures and enthalpy changes of the porphyrin derivatives, 1–8 (Type 3) (Type 6) (Type 5) X 52.5 48 [ ca.15] K5 IL(decomp.) K 60.4[55.6] DL 200.7[49.8] IL K2 K1 K3 K4 X 40.1 98.2 190.8 430.9 450.5 ca.50 [7.24] [6.74] [24.2] [59.6] (C12O)4-BPPH2 7 (C12O)2-BBPH2 8 69.8[111.0] 39.2[42.2] DLa(DL.rec1) DLb(DL.rec2) IL 76.0[24.7] 228.6[43.3] 136.7[49.0] IL Drd(C2/m) X Drd(P21/a) Drd(C2/m) IL 132.9[48.2] X (C12O)8-BTPH2 4 (C16O)8-BTPH2 5 (C12O)4-BTPH2 6 204.5 202.2 Rapid cooling IL IL K2 K1 37 IL X X1 M1(Dho) IL X2 M2(Dhd) IL ca.-80 ca. -35 59 X Dhd IL -37[67.9] 57[23.1] : relaxation (C12O)8-TTPH2 3 (C8O)16-TTPH2 2 (C12O)16-TTPCu 1-Cu (C12O)16-TTPH2 1 Compound Phase* Phase Tt /°C[D H/(kJ mol–1)] 39[ ca. 90] (Type 4) b Phase nomenclature: K=crystal, Dhd=discotic hexagonal disordered columnar mesophase, Drd=discotic rectangular disordered columnar mesophase, DL=discotic lamellar mesophase, X=unidentified phase, and IL=isotropic liquid.angle region and the halo around 2h=20°, this higher-tempera- endothermic peak was observed at 37 °C in the DSC thermogram: 5.55 kJ mol-1 for the first heating run and 2.15 kJ mol-1 ture phase could be also assigned as a Dh mesophase, the same as the lower-temperature phase.In contrast to the lower- for the second heating run. Under a polarizing microscope, it showed an almost isotropic texture with very weak birefrin- temperature Dh mesophase, the higher one showed a very broad and weak halo in the middle angle region which gence. When the cover glass was pressed, it was too rigid to slip. For the X-ray diVraction study, only two broad reflections corresponds to the dimer-stacking distance.In this mesophase, the stacking distance fluctuates greatly, so that we assigned were observed in the low and wide angle regions. Therefore, this state is thought to be a glassy liquid phase26 or a this phase as a Dhd mesophase. However, we could still see the halo corresponding to the stacking distance. It is very supercooled liquid with a slightly crystallized portion.The crystalline part may melt at 37 °C. The enthalpy change diYcult to distinguish between Dho and Dhd mesophases for such a case. Therefore, we tentatively assigned these lower- depended on the degree of crystallization, as mentioned above. Since a glassy transition point was not detected by DSC and higher-temperature mesophases as Dho and Dhd, respectively (Table 4).When the IL was held at 58 °C, a focal-conic measurements, this state my be a supercooled isotropic liquid state with a partially crystallized portion. texture appeared for the Dh phase [Fig. 3(a)]. This texture is often observed in Dh mesophases. As summarized in Table 3, (C12O)8-TTPH2 (3) has very high melting points in comparison with 1 and 2 having sixteen As summarized in Table 3, (C12O)16-TTPCu (1-Cu) showed rather more simple phase transition behavior than the metal- long chains.Though the derivative 3 exhibits no mesomorphism, it shows double-melting behavior in a narrow free compound 1, and its clearing point is nearly the same as that of the Dhd phase of 1. From the results of X-ray diVraction temperature region. Type 2 meso-substituted porphyrin derivatives with bulky measurements at r.t.(Table 4), this phase could be identified as a Dhd mesophase. When the IL of (C12O)16-TTPCu (1-Cu) substituents (in Fig. 1) which have been reported to date show not columnar mesophases but lamellar mesophases.13,27,28 was held for some time, a focal-conic texture appeared in the same way as its metal-free compound 1.Although type 4 (C12O)16-TTPH2 (1) and (C12O)16-TTPCu (1-Cu) derivatives have larger steric hindrance groups than For the (C8O)16-TTPH2 (2) derivative, only a very small 2642 J. Mater. Chem., 1998, 8, 2637–2650Table 4 X-Ray diVraction data of the porphyrin derivatives 1–8 Spacing (A° ) Peak Miller indices Phase Compound No. dobserved dcalculated (hkl ) Lattice constant (C12O)16-TTPH2 (1) 1 36.0 36.0 (100) Dho at r.t.a 2 21.4 20.8 (110) 3 9.55 sharp (001) a=41.5 A° 4 ca. 4.3 — —b h=9.55 A° , Z=2 at 55 °C 1 34.4 34.4 (100) Dhd 2 19.9 19.9 (110) 3 ca. 9.1 broad (001) a=39.7 A° 4 ca. 4.4 — —b h=ca. 9.1 A° (C12O)16-TTPCu(1-Cu) 1 36.3 36.3 (100) Dhd at r.t. 2 21.2 20.9 (110) 3 ca. 9.3 broad (001) a=41.9 A° 4 ca. 4.4 — —b h=ca. 9.1 A° (C12O)8-BTPH2 (4) 1 33.2 33.2 (110) Drd (C2/m) at 125 °C 2 29.8 29.8 (200) 3 16.6 16.6 (220) a=59.7 A° 4 ca. 4.4 — —b b=40.0 A° (C16O)8-BTPH2 (5) 1 37.0 37.0 (200) Drf (P21/a) at 60 °C 2 34.8 34.8 (110) 3 18.8 19.1 (120) a=74.1 A° 4 13.4 13.5 (420) b=39.4 A° 5 10.7 10.7 (430) 6 4.41 — —c 7 4.14 — —c at 120 °C 1 41.7 41.7 (110) Drd(C2/m) 2 36.3 36.3 (200) 3 22.0 21.9 (310) a=72.6 A° 4 10.5 10.4 (440) b=51.0 A° 5 ca. 4.6 — —b (C12O)4-BTPH2 (6) 1 34.9 34.2 (001) DLa(DL.rec1) at r.t. 2 16.7 17.1 (002) 3 11.0 11.0 (010) a=16.1 A° 4 9.10 9.10 (110) b=11.0 A°5 5.40 5.37 (300) c=34.2 A° 6 4.79 4.83 (310) Z=2 7 4.53 4.55 (220) 8 ca. 4.1 — —b Alternative 1 34.9 34.2 (001) DLa(DL.rec1) assignment 2 16.7 17.1 (002) at r.t. 3 11.0 11.0 (100) a=11.0 A° 4 9.10 9.10 (010) b=9.1 A° 5 5.40 5.52 (200) c=34.2 A° 6 4.79 4.72 (210) 7 4.53 4.55 (020) Z=1 8 ca. 4.1 — —b at 220 °C 1 39.7 39.3 (001) DLb(DL.rec2) 2 19.7 19.7 (002) 3 12.9 13.1 (003) a=18.6 A° 4 10.9 10.9 (010) b=10.9 A° 5 9.40 9.40 (110) c=39.3 A° 6 6.38 6.19 (300) Z=2 7 ca. 5.0 — —b Alternative 1 39.7 39.3 (001) DLb(DL.rec2) assignment 2 19.7 19.7 (002) at 220 °C 3 12.9 12.9 (010) a=19.2 A° 4 10.9 10.7 (110) b=12.8 A° 5 9.40 9.60 (200) c=39.3 A° 6 6.38 6.40 (020) 7 ca. 5.0 — —b Z=4 aMeasured in virgin state. bHalo of melting of alkyl chain. cSee the main text. type 2 derivatives, they show Dh mesophases as described long chains at the b-positions of the pyrrole rings, the metalfree compounds tend to show no mesomorphism whereas the above. This may be attributed to the sixteen melting long alkyl chains which completely fill the space around the porphyrin metal complexes tend to exhibit columnar mesophases.8,12 On the other hand, in type 2 meso-substituted derivatives, both core to allow the molecules to form a columnar assembly.In conclusion of this section, the (C12O)16-TTPH2 (1) and the metal-free and metal compounds frequently have the same mesophase (in most cases DL mesophase).13,27,28 In this work, (C12O)16-TTPCu (1-Cu) derivatives are the first examples of tetraphenylporphyrin derivatives exhibiting Dh mesophases. both the metal-free compound 1 and its copper complex 1-Cu show the same Dhd mesophase.Thus, the eVect of the central Generally speaking, in type 1 porphyrin derivatives with J. Mater. Chem., 1998, 8, 2637–2650 2643Fig. 3 Photomicrographs of (a) the Dhd mesophase of (C12O)16-TTPH2 (1) at 58°C, (b) the Dhd mesophase of (C12O)16-TTPCu (1-Cu) at 56°C, (c) whiskers of the Drd (C2/m) mesophase of (C12O)8-BTPH2 (4) at 136 °C, (d) the DLb mesophase of (C12O)4-BTPH2 (6) at 226 °C, and (e) the DL mesophase of (C12O)4-BPPH2 (7) at 198 °C.metal on the mesomorphism in type 2 and 4 compounds may pattern for this compound at 125 °C (Table 4) gave three narrow peaks in the low angle region and a diVuse band be negligible Hence, we synthesized only metal-free compounds and studied their mesomorphism in our subsequent work.around 2h=20° which correspond to the melting of alkyl chains. This phase could be then assigned to a discotic rectangular disordered columnar (Drd) mesophase. 2-2-2. (CnO)m-BTPH2 (4, 5, and 6; type 5).Table 3 also summarizes the phase transition temperatures and the enthalpy Furthermore, it was established from the extinction rules in two-dimensional rectangular lattices that this Drd mesophase changes of (C12O)8-BTPH2 (4), (C16O)8-BTPH2 (5) and (C12O)4-BTPH2 (6). All the type 5 compounds 4–6 synthesized has C2/m symmetry (Table 4). (C16O)8-BTPH2 (5) in the pristine state at room temperature here exhibit mesomorphism.(C12O)8-BTPH2 (4) shows an unidentified phase (denoted is a mixture of an unidentified phase (X phase) and a Drd (P21/a) mesophase. The X and Drd (P21/a) phases both change as X phase) at r.t. On heating, this X phase transforms to a Drd (C2/m) mesophase at 39.2 °C, and it clears to the IL at into a Drd (C2/m) phase at 48 and 69.8 °C, respectively.The X phase does not appear without the first heating run. The 136.7 °C. The values of the enthalpy changes for these two phase transitions are roughly the same. The X-ray diVraction X-ray diVraction pattern for this compound at 120 °C showed 2644 J. Mater. Chem., 1998, 8, 2637–2650four narrow peaks in the low angle region and a broad fifth In conclusion of this section, type 5 (C12O)8-BTPH2 (4) and (C16O)8-BTPH2 (5) derivatives having eight long alkoxy chains peak 5 around 2h=20° (Table 4).This phase could be assigned to a Drd (C2/m) mesophase. It is the same phase as that in show Drd mesophases. On the other hand, the type 5 (C12O)4- BTPH2 (6) derivative having four long alkoxy chains exhibits (C12O)8-BTPH2 (4). When the sample was heated to clear, and then cooled to r.t., it gave a pure mesophase.The X-ray two DL.rec. mesophases. It is very interesting that the mesophases in type 5 change from the Drd phase with columnar diVraction pattern of the mesophase at 60 °C gave seven narrow peaks (Table 4). From five peaks in the low angle structure to the DL phase with lamellar structure when the number of attached long alkyl chains is reduced by half.region, this phase could be assigned to a Drd (P21/a) mesophase. The remaining two peaks at wide angles could not be Furthermore, it was found that the DL mesophases in the (C12O)4-BTPH2 (6) derivatives have two-dimensional assigned to reflections from the two-dimensional rectangular P21/a lattice. They probably indicate that the long aliphatic rectangular order within the layer.chains partially crystallize within the intercolumnar space, similarly to the Dh phase of bis(octaoctadecylphthalocyanina- 2-2-3. (C12O)4-BPPH2 (7; type 6). The phase transition behavior of (C12O)4-BPPH2 (7) is summarized in Table 3. The to)lutetium complex.29 When the IL of (C12O)8-BTPH2 (4) was held for a few pristine sample showed two endothermic peaks at 52.5 °C and 60.4 °C which were mutually overlapped in the DSC thermo- hours just below its clearing point, ‘whisker growth’ was observed [Fig. 3(c)]. Although the materials which were grams. The endothermic peak at 52.5 °C did not appear for the non-pristine sample. Thus, the pristine state of this com- reported to form whiskers are mainly inorganic compounds, polymers such as poly(4-hydroxybenzoate)30 and organic com- pound at r.t.is a mixture of an unidentified X phase and a crystalline K phase. The X phase could not be characterized pounds such as L-alanine31 were also reported to form whiskers. Generally, crystal whiskers are needle-like, whereas the because the pure phase could not be obtained. The nonpristine sample showed two reproducible endothermic peaks whisker in the case of (C12O)8-BTPH2 (4) is bent.Bending of whiskers has been described to be caused by characteristic at 60.4 °C and 200.7 °C. As can be seen in Table 3, the enthalpy change at the lower phase transition is somewhat larger than defects in structures composed of stacks of disc-like molecules, 32 so that it can evidence the columnar mesomorphism that of the higher phase transition.The X-ray diVraction pattern of this compound at 170 °C of (C12O)8-BTPH2 (4). Another example of such bent whiskers has been reported in 2,4,6-tris(didecylamino)-s-triazine.32 The gave large peaks in the low angle region which were characteristic of lamellar phases and the layer spacing could be calcu- same whiskers could be also seen for the homologous (C16O)8- BTPH2 (5) derivative under similar conditions to the (C12O)8- lated to be c=31.7 A° .Several comparatively small peaks on a diVuse halo at wide angles could not be assigned, because BTPH2 (4) derivative, although the whiskers were not so large in 5. these peaks became bigger and sharper during the several hours’ X-ray measurements and additional peaks appeared.Both (C12O)8-BTPH2 (4) and (C12O)4-BTPH2 (6) are classified as type 5, although 4 and 6 have eight and four long This phenomenon is due to relaxation from DL to another unidentified crystalline phase. chains (dodecyloxy groups), respectively. As summarized in Table 3, (C12O)4-BTPH2 (6) shows a transformation from the When the IL of (C12O)4-BPPH2 (7) was held at 198 °C for a few minutes, a texture with a terraced structure appeared as DLa to the DLb phase at 76.0 °C (subscripts a and b are used not to express phase features but only to distinguish the shown in Fig. 3(e). This indicates the existence of lamellar structure in the DL mesophase. diVerent phases), and DLb clears to the IL at 228.6 °C. The clearing point of this compound is ca. 90 °C higher than those As mentioned above, the X-ray diVraction pattern for (C12O)4-BPPH2 (7) showed a halo corresponding to the melt- of (C12O)8-BTPH2 (4) and (C16O)8-BTPH2 (5), and the stability of the mesophase rises.As summarized in Table 4, the X- ing of the alkyl chains around 2h=20°. Accordingly, the alkyl chains seem to fluctuate in this phase. The fluctuation of the ray diVraction pattern of (C12O)4-BTPH2 (6) at 220 °C gave seven peaks.Since peak 7 was broad, it corresponds to melting alkyl groups of 7 was then studied by means of temperaturedependent IR spectroscopy. The vibrational spectral changes of the alkyl chains. The ratio of the spacings of peaks 1–3 in the low angles is 151/251/3, which represents the existence of of the phase transitions of n-paraYn34,35 bilayer systems36 and discotic liquid crystals37 have been reported.The temperature lamellar structure. The remaining peaks 4–6 could be assigned to the reflections from a two-dimensional rectangular lattice. dependence of the methylene rocking band of phase II (‘rotator’ or ‘hexagonal’38 phase) of n-paraYns has been Hence this mesophase was proven to be a lamellar mesophase having two-dimensional rectangular order within the layer studied in detail, because this band which usually appears near 720 cm-1 is very sensitive to structural changes caused by (DLb=DL.rec.2).Besides, from the X-ray diVraction data at r.t., the DLa phase is also a lamellar mesophase with two- phase transitions. The crystalline state of 7 showed two bands near 745 and dimensional rectangular order within the layer (Table 4, DLa= DL.rec.1).Interestingly, alternative two-dimensional lattice con- 723 cm-1 at 30 °C. The band near 720 cm-1 is usually assigned to the methylene rocking mode in all-trans alkyl chains. It stants, 11.0 A° ×9.10 A° and 19.2 A° ×12.8 A° , also fit well for DLa at r.t. and for DLb at 220 °C, respectively, as listed in splits into two bands in the solid state because of factor group splitting.The interval (ca. 22 cm-1) between these two bands Table 4. Generally, a limited number of sharp peaks in mesophases make it diYcult to reach an unambiguous two-dimen- is fairly wide in comparison with general splitting width (ca. 10 cm-1) of the well-discussed factor group splitting.35,36,38 sional lattice assignment.Further investigation is required for the detailed structural diVerences between these DLa and DLb Therefore, it seems that the two bands of the present case are not usual. Snyder39 reported that the methylene rocking band phases. We recently found two novel discotic lamellar DL.rec mesophases,33 whose structures in the layers may be closely of molten polyethylene had been graphically resolved into two components at 719 cm-1 and 745 cm-1, and that the higher- related to those of the present DLa and DLb mesophases.As shown in Fig. 3(d), the terrace texture with piles of frequency component at 745 cm-1 was near the value calculated for alternating trans–gauche sequences. Hence, this com- plates could be observed under a polarizing microscope when the IL of (C12O)4-BTPH2 (6) was slowly cooled to 226 °C. pound at 30 °C may have a considerable proportion of gauche bonds in the aliphatic chains, as is the case in the references This indicates the existence of lamellar structure in the DLb mesophase.The plates in the texture were striated in the mentioned above. The ratios of the absorbances of the two bands for 7 are temperature region of the DLa mesophase below 76.0 °C, but no dramatic change was observed.This also suggests that both plotted against temperature in Fig. 4. When the sample was heated to 60.4 °C above the melting point of 7, the intensity DLa and DLb phases have lamellar structure. J. Mater. Chem., 1998, 8, 2637–2650 2645and long flexible chains in order to investigate their mesomorphism.Fig. 5 summarizes the relationship between the molecular type of porphyrin derivatives, 1–8 and 1-Cu, and the resulting mesophase. Type 4 disc-like (C12O)16-TTPH2 (1) and (C12O)16- TTPCu (1-Cu) derivatives exhibit Dh columnar mesophases, which are the first examples of meso-substituted porphyrin metal-free derivatives and copper complexes. Type 5 strip-like (CnO)8-BTPH2 [4 (n=12), 5 (n=16)] derivatives having eight long chains at the 5,15-positions show the Drd columnar mesophases.On the other hand, type 5 (C12O)4-BTPH2 (6) derivative having four long chains exhibits DL.rec1 and DL.rec2 lamellar mesophases which have two-dimensional rectangular structure within the layer. The (C12O)4-BPPH2 (7) derivative, of type 6, also shows a DL lamellar mesophase. Bruce et al.17 reported that the type 3 rod-like porphyrin derivatives show calamitic mesophases of SB, SE and SE¾ phases.As can be seen from the top derivative to the bottom one in Fig. 5, it is, therefore, apparent that such a successive change of the Fig. 4 Temperature dependence of the absorption ratio of two methylene rocking bands at ca. 720 and 740 cm-1 (A720/A740) for molecular structures causes their mesophases to change from (C12O)4-BPPH2 (7).discotic columnar to discotic lamellar, and further to calamitic. It is also apparent that the porphyrin core is very useful to obtain various kinds of mesomorphism from discotic to calam- of the lower-frequency band at ca. 723 cm-1 suddenly decreased, and the higher-frequency band at ca. 745 cm-1 itic with alteration of the substituted positions and/or substituents.slightly shifted to lower frequency. On further heating, the bands gradually broadened, and a broad band remained at 734 cm-1 in the isotropic liquid at 210 °C. The ratio discontinuously altered at the melting point. As can be seen in Fig. 4, 4. Experimental the absorption band at 723 cm-1 suddenly decreased at the 4-1.Measurements phase transition. This may suggest that some trans bonds of the methylene groups change into gauche bonds upon heating The products synthesized here were identified by 1H NMR to break all-trans sequences. The broadening of the bands may (JOEL JNM-PMX60SI) and IR (Jasco A-100). Further identibe due to disorder of the alkyl chains melted by heating. fication of the porphyrin derivatives was made by elemental However, since trans bonds in n-hydrocarbons are normally analysis (Perkin-Elmer elemental analyzer 240B) and electronic more stable than gauche bonds, the absorption of trans bonds absorption spectroscopy (Hitachi 330 spectrophotometer).should be more intense than gauche ones. In the molten state, The phase transition behaviors of these compounds were e.g., liquid n-paraYn and molten polyethylene, all-trans meth- observed by using a polarizing microscope (Olympus BH2), ylene rocking bands remain fairly even when they broaden. equipped with a heating plate controlled by a thermoregulator An explanation for the diVerence between the conventional (Mettler FP80 and FP82), and diVerential scanning calorresults and the present results has not been obtained. imetry (Shimadzu DSC-50 and Rigaku Thermoflex DSCNevertheless, it is at least supported that the long alkyl chains 8230).The X-ray diVraction measurements were performed of 7 are fairly disordered in the liquid crystalline state of the with Cu-Ka radiation (Rigaku Geigerflex) equipped with a DL phase. hand-made heating plate40 controlled by a thermoregulator.Temperature-dependent infrared spectra were measured by a 2-2-4. (C12O)2-BBPH2 (8; type 3). In an attempt to obtain Jasco FT/IR-7300 instrument equipped with a hand-made a calamitic mesophase in porphyrin derivatives, a rod-like heating plate41 controlled by a thermoregulator for a thin film (C12O)2-BBPH2 (8) derivative was synthesized. The phase of (C12O)4-BPPH2 (7).This thin film was prepared by casting transition behavior of (C12O)2-BBPH2 (8) is summarized in from a dichloromethane solution on a silicon wafer, then the Table 3. It was revealed by means of DSC measurements that solvent was removed by heating, and the film covered by this compound shows many phase transitions, and that it another wafer. finally showed an endothermic peak at 450.5 °C which may be assigned to the clearing point with decomposition.All the 4-2. Synthesis phases exhibited below 300 °C turned out to be crystalline phases according to polarizing microscopic observations and 3,4-Bis(3,4-didodecyloxyphenyl )-4-hydroxycyclopent-2-en-1- one(14a). This compound was synthesized by a similar method X-ray diVraction study. The phase between 430.9 °C and 450.5 °C, only detected by DSC measurements, could not be as described in previous papers.42,43 14a: Purified by column chromatography (silica gel, chloro- identified because of the high temperature which exceeds our instrumental limits.Consequently, this phase is termed an X form–ethyl acetate 551; Rf=0.68). Yellow liquid crystal (SA). Clearing point (c.p.) 55 °C ( lit.43 54 °C).Yield 74%. 1H NMR phase. The possibility of mesomorphism of this X phase still remains because the value of DH at the XAIL transition is (CDCl3, TMS) d 0.90 (m, 12H, CH3), 1.27 (m, 80H, CH2), 2.73 (s, 2H, CH2CO), 3.40–4.06 (m, 9H, OH and OCH2), 6.27 smaller than that at the K4AX transition. This compound has a highly rigid molecule in comparison with the aforemen- (s, 1H, NCHCO), 6.43–7.03 (m, 6H, Ph).IR(neat) nmax 3400 (OH), 2930, 2860 (CH2), 1680 (CO), 1590, 1510 (Ph), tioned compounds exhibiting mesomorphism. Thus, (C12O)2- BBPH2 (8) retains its crystal structure even at high 1260 cm-1 (ROPh). 14b: Purified by column chromatography (silica gel, temperature. chloroform–ethyl acetate 551; Rf=0.60). Yellow liquid crystal (SA). c.p. 42.5 °C.Yield 55%. 1H NMR (CCl4, TMS) d 0.85 3. Conclusion (m, 12H, CH3), 1.30 (m, 48H, CH2), 2.67 (s, 2H, CH2CO), 3.47 (s, 1H, OH), 3.57–3.97 (m, 8H, OCH2), 6.23 (s, 1H, We have synthesized nine novel porphyrin derivatives, 1–8 and 1-Cu, substituted with various steric hindrance groups NCHCO), 6.37–7.10 (m, 6H, Ph). IR (neat) nmax 3350 (OH), 2646 J. Mater. Chem., 1998, 8, 2637–2650Mesophase Type 3* Type 6 (7) Type 5 (6) Type 5 (4,5) Type 4 (1, 1-Cu) Type No.(Compound) DL.rec Dh Drd DL SB,SE,SE' NH N HN N C12H25O C12H25O OC12H25 OC12H25 C12H25O C12H25O OC12H25 OC12H25 NH N HN N N N N N Zn OCnH2 n+1 CnH2 n+1O N N N N C12H25O OC12H25 OC12H25 C12H25O OC12H25 OC12H25 OC12H25 C12H25O OC12H25 OC12H25 C12H25O C12H25O OC12H25 C12H25O C12H25O OC12H25 M NH N N HN OCnH2 n+1 OCnH2 n+1 CnH2 n+1O OCn H2 n+1 CnH2 n+1O CnH2 n+1O OCnH2 n+1 CnH2 n+1O Fig. 5 The relationship between the molecular type of porphyrin derivatives and the resulting mesophase. (*see ref. 17). 2930, 2860 (CH2), 1675 (CO), 1590, 1510 (Ph), 1260 cm-1 3380 (OH), 2930, 2860 (CH2), 1680 (CO), 1590, 1510 (Ph), 1250 cm-1 (OPh). (ROPh). 14c: Purified by column chromatography (silica gel, chloroform–ethyl acetate 551; Rf=0.74).Yellow solid. Methyl 3,4,3,4-tetradodecyloxy-o-terphenyl-4¾-carboxylate (15a). A mixture of cyclopentenone 14a (4.60 g, 4.66 mmol) m.p. 56–57 °C. Yield 62%. 1H NMR (CDCl3, TMS) d 0.83 (m, 12H, CH3), 1.20 (m, 112H, CH2), 2.80 (s, 2H, CH2CO), and methyl propiolate (1.17 g, 13.9 mmol) in 50 ml of odichlorobenzene was heated at 70 °C. A solution of p-tolu- 3.57 (s, 1H, OH), 3.80 (m, 8H, OCH2), 6.33 (s, 1H, NCHCO), 6.53–7.03 (m, 6H, Ph).IR (KBr) nmax 3350 (OH), 2930, 2860 enesulfonic acid monohydrate (47.8 mg, 0.25 mmol) in 2 ml of 1,4-dioxane was added dropwise. The mixture was stirred (CH2), 1675 (CO), 1590, 1510 (Ph), 1260 cm-1 (ROPh). 14d: Purified by column chromatography (silica gel, for 4 h at 70 °C, and then refluxed for 8 h 40 min.The reaction mixture was extracted with chloroform. The organic layer was chloroform–ethyl acetate 551; Rf=0.54). Pale yellow solid. m.p. 66–69 °C ( lit.42 65–68 °C). Yield 49%. 1H NMR (CCl4, washed with water, dried over sodium sulfate, and the solvent was removed. The purification was carried out by column TMS) d 0.87 (m, 6H, CH3), 1.30 (m, 40H, CH2), 2.70 (s, 2H, CH2CO), 3.50 (s, 1H, OH), 3.80 (t, J=6.0 Hz, 4H, OCH2), chromatography (silica gel, benzene–carbon tetrachloride 151; Rf=0.50), to obtain 2.24 g of 15a as a yellowish-brown solid. 6.27 (s, 1H, NCHCO), 6.47–7.57 (m, 6H, Ph). IR (neat) nmax J. Mater. Chem., 1998, 8, 2637–2650 2647m.p. 55 °C. Yield 47%. 1H NMR (CCl4, TMS) d 0.88 (m, NMR (CCl4, TMS) d 0.88 (m, 12H, CH3), 1.27 (m, 48H, CH2), 3.17–4.00 (m, 8H, OCH2), 6.27–7.80 (m, 9H, Ph), 9.83 12H, CH3), 1.27 (m, 80H, CH2), 3.42, 3.83 (t+t, 8H, OCH2), 3.83 (s, 3H, COOCH3), 6.40–7.97 (m, 9H, Ph).IR (neat) nmax (s, 1H, CHO). IR (neat) nmax 1695 cm-1 (CO). 17c: Purified by column chromatography (silica gel, benzene; 1720 cm-1 (CO). 15b: Purified by column chromatography (silica gel, benzene; Rf=0.55). Yellowish white solid.m.p. 58 °C. Yield 93%. 1H NMR (CCl4, TMS) d 0.88 (m, 12H, CH3), 1.25 (m, 112H, Rf=0.60). Yellowish brown syrup. Yield 44%. 1H NMR (CCl4, TMS) d 0.87 (m, 12H, CH3), 1.30 (m, 48H, CH2), CH2), 3.40–4.07 (m, 8H, OCH2), 6.37–7.80 (m, 9H, Ph), 9.87 (s, 1H, CHO). IR (KBr) nmax 1695 cm-1 (CO). 3.27–4.00 (t+t, 8H, OCH2), 3.83 (s, 3H, COOCH3), 6.33–8.00 (m, 9H, Ph). IR (neat) nmax 1725 cm-1 (CO). 17d: Purified by column chromatography (silica gel, benzene; Rf=0.60). Yellow syrup. Yield 95%. 1H NMR (CCl4, TMS) 15c: Purified by column chromatography (silica gel, benzene–carbon tetrachloride 251; Rf=0.56). Light brown d 0.90 (m, 6H, CH3), 1.30 (m, 40H, CH2), 3.83 (t, J=6.0 Hz, 4H, OCH2), 6.40–7.77 (m, 11H, Ph), 9.87 (s, 1H, CHO). IR solid. m.p. 50 °C. Yield 49%. 1H NMR (CCl4, TMS) d 0.87 (m, 12H, CH3), 1.30 (m, 112H, CH2), 3.40–4.00 (m, 8H, (neat) nmax 1700 cm-1 (CO). OCH2), 3.83 (s, 3H, COOCH3), 6.33–7.90 (m, 9H, Ph). IR (KBr) nmax 1720 cm-1 (CO). 5,10,15,20-Tetrakis(3,4,3,4-tetradodecyloxy-o-terphenyl )- porphyrin [1; (C12O)16-TTPH2]. A mixture of aldehyde 17a 15d: Purified by column chromatography (silica gel, benzene–carbon tetrachloride 151; Rf=0.45).Yellowish brown (1.48 g, 1.49 mmol) and pyrrole (0.23 g, 3.43 mmol) in propionic acid (10 ml, 0.13 mol ) was refluxed for 30 min. After the syrup. Raw yield 71% (this product contained some impurities.). 1H NMR (CCl4, TMS) d 0.90 (m, 6H, CH3), 1.27 (m, reaction mixture was cooled to room temperature, sodium hydroxide (5.20 g, 0.13 mol) was added. The mixture was 40H, CH2), 3.80 (m, 7H, OCH2, COOCH3), 6.47–7.87 (m, 11H, Ph). IR (neat) nmax 1725 cm-1 (CO).extracted with diethyl ether, and the organic layer was washed with water. After being dried and concentrated, the residue was purified by column chromatography (alumina, benzene; 3,4,3,4-Tetradodecyloxy-4¾-hydroxymethyl-o-terphenyl (16a). Under a nitrogen atmosphere, a solution of carboxylate Rf=1.00) to yield 0.38 g of the crude (chlorin-contained) porphyrin derivative.The crude product was dissolved in the 15a (2.11 g, 2.06 mmol) in 20 ml of dry diethyl ether was added dropwise to a suspension of lithium aluminium hydride minimum amount of chloroform and a small amount of benzene. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ; (LiAlH4; 0.31 g, 8.17 mmol) in 15 ml of dry diethyl ether.The mixture was gently refluxed for 1 h. After the reaction mixture 0.14 g, 0.62 mmol) was added, and the mixture was refluxed for 3 h. The mixture was concentrated and the residue was was cooled by ice water, water was added slowly till no LiAlH4 remained. Then, a small amount of 20% sulfuric acid was purified by column chromatography (silica gel, benzene; Rf= 1.00, and alumina, hexane; Rf=0.00, chloroform; Rf=1.00) added to dissolve the precipitate, and extracted with diethyl ether.The organic layer was washed with water, dried over to give 0.22 g of 1 as a red-purple liquid crystal. Yield 14%. 1H NMR (CDCl3, TMS) d -2.63 (s. 2H, NH), 0.80 (m, 48H, sodium sulfate, and concentrated. The residue was purified by column chromatography (silica gel, chloroform; Rf=0.44) to CH3), 1.26 (m, 320H, CH2), 3.44–4.10 (m, 32H, OCH2), 6.52–8.24 (m, 36H, Ph), 8.90 (s, 8H, porphyrin).IR (neat) give 1.58 g of 16a as a faintly-brown syrup. Yield 93%. 1H NMR(CCl4, TMS) d 0.90 (m, 12H, CH3), 1.30 (m, 80H, nmax 3320 (NH), 2930, 2860 (CH2), 1600, 1580 (Ph), 1260 cm-1 (ROPh). CH2), 1.70 (s, 1H, OH), 3.43–4.00 (m, 8H, OCH2), 4.60 (s, 2H, PhCH2O), 6.40–7.23 (m, 9H, Ph).IR (neat) nmax 3330 cm-1 (OH). 5,10,15,20-Tetrakis(3,4,3,4-tetraoctyloxy-o-terphenyl )- porphyrin [2; (C8O)16-TTPH2]. The title compound was synthe- 16b: Purified by column chromatography (silica gel, chloroform; Rf=0.21). Pale brown syrup. Yield 90%. 1H sized from aldehyde 17b according to the method described above, and purified by column chromatography (alumina, NMR (CCl4, TMS) d 0.87 (m, 12H, CH3), 1.30 (m, 48H, CH2), 2.26 (s, 1H, OH), 3.30–4.00 (t+t, 8H, OCH2), 4.58 (s, benzene and chloroform; Rf=1.00, and silica gel, hexane; Rf= 0.00 and benzene; Rf=1.00).Red-purple solid. Yield 17%. 1H 2H, PhCH2O), 6.33–7.26 (m, 9H, Ph). IR (neat) nmax 3200 cm-1 (OH). NMR(CDCl3, TMS) d -2.63 (s. 2H, NH), 0.57–1.00 (m, 48H, CH3), 1.00–2.33 (m, 192H, CH2), 3.44–4.17 (m, 32H, 16c: Purified by column chromatography (silica gel, chloroform; Rf=0.38).White solid. m.p. 52 °C. Yield 67%. 1H OCH2 ), 6.47–8.27 (m, 36H, Ph), 8.90 (s, 8H, porphyrin). IR (neat) nmax 3320 (NH), 2930, 2860 (CH2), 1605, 1580, 1510 NMR (CCl4, TMS) d 0.88 (m, 12H, CH3), 1.27 (m, 112H, CH2), 1.63 (s, 1H, OH), 3.33–4.00 (m, 8H, OCH2), 4.55 (s, (Ph), 1250 cm-1 (ROPh). 2H, PhCH2O), 6.27–7.20 (m, 9H, Ph). IR (KBr) nmax 3300 cm-1 (OH). 5,10,15,20-Tetrakis(4,4-didodecyloxy-o-terphenyl )- porphyrin [3; (C12O)8-TTPH2]. The title compound was synthe- 16d: Purified by column chromatography (silica gel, chloroform; Rf=0.40). Pale orange solid. m.p. 47.5 °C. Yield sized from aldehyde 17d according to the method described above, and purified by column chromatography (silica gel, 42%. 1H NMR (CCl4, TMS) d 0.90 (m, 6H, CH3), 1.27 (m, 40H, CH2), 1.93 (s, 1H, OH), 3.80 (t, J=6.0 Hz, 4H, OCH2), chloroform; Rf=1.00, alumina, carbon tetrachloride; Rf=0.00, and benzene; Rf=1.00) and recrystallization (hexane, ethyl 4.53 (s, 2H, PhCH2O), 6.47–7.13 (m, 11H, Ph). IR (neat) nmax 3330 cm-1 (OH). acetate). Purple solid.Yield 15%. 1H NMR (CCl4, TMS) d -2.53 (s, 2H, NH), 0.90 (m, 24H, CH3), 1.67 (m, 160H, CH2), 3.77 (m, 12H, OCH2), 6.40–8.30 (m, 44H, Ph), 8.90 (s, 3,4,3,4-Tetradodecyloxy-o-terphenyl-4¾-carbaldehyde (17a). A mixture of hydroxymethyl 16a (1.54 g, 1.54 mmol) and 8H, porphyrin). IR (film) nmax 3320 (NH), 2930, 2860 (CH2), 1610, 1510 (Ph), 1250 cm-1 (ROPh). pyridinium dichromate (PDC; 0.87 g, 2.31 mmol) in 3 ml of dichloromethane was stirred for 10 h.The reaction mixture was concentrated and the residue was purified by column 5,10,15,20-Tetrakis(3,4,3,4-tetradodecyloxy-o-terphenyl )- porphyrinatocopper(II ) [1-Cu; (C12O)16-TTPCu]. Porphyrin 1 chromatography (silica gel, benzene; Rf=0.70) to give 1.46 g of 17a as a yellowish white solid. m.p. 64–65 °C.Yield 95%. (0.12 g, 2.88×10-2 mmol) and anhydrous cupric chloride (0.04 g, 0.30 mmol) were dissolved in 30 ml of dry N,N- 1H NMR (CCl4, TMS) d 0.88 (m, 12H, CH3), 1.30 (m, 80H, CH2), 3.40–4.13 (m, 8H, OCH2), 6.40–7.85 (m, 9H, Ph), 9.92 dimethylformamide (DMF) and refluxed for 5 h. The reaction mixture was cooled and separated by filtration. The remaining (s, 1H, CHO). IR (neat) nmax 1700 cm-1 (CO). 17b: Purified by column chromatography (silica gel, precipitate was washed by methanol, and purified by column chromatography (alumina, benzene; Rf=1.00) to give 0.11 g chloroform; Rf=0.65). Brownish yellow syrup. Yield 98%. 1H 2648 J. Mater. Chem., 1998, 8, 2637–2650of 1-Cu as a dark red liquid crystal. Yield 90%. IR (neat) nmax Rf=1.00) and recrystallization from ethyl acetate and dichloromethane.Reddish brown solid. Yield 39%. 1H NMR 2930, 2860 (CH2), 1610, 1580 (Ph), 1250 cm-1 (ROPh). (CCl4, TMS) d -3.00 (broad, 2H, NH), 0.83 (m, 12H, CH3), 1.20 (m, 80H, CH2), 3.46–4.40 (m, 8H, OCH2), 6.40–8.00 (m, 4-Dodecyl-4¾-bromobiphenyl (21). A mixture of 4-hydroxy- 4¾-bromobiphenyl 20 (2.00 g, 8.03 mmol) and potassium 22H, Ph), 8.83 (s, 8H, porphyrin), 9.77 (s, 2H, meso-H).IR (KBr) nmax 3300 (NH), 2930, 2860 (CH2), 1610 (Ph), hydroxide (0.90 g, 16.0 mmol) in 15 ml of ethanol was refluxed for 1 h. Then a solution of dodecyl bromide (2.10 g, 1245 cm-1 (ROPh). 8.43 mmol) in 5 ml of ethanol was added, and the mixture was further refluxed for 13 h. After cooling to room tempera- 5,15-Bis(3,4-didodecyloxyphenyl )porphyrin [7; (C12O)4- ture, the reaction mixture was filtered with suction.The BPPH2]. The title compound was synthesized from 3,4-didoderesidual precipitate was washed with water and recrystallized cyloxybenzaldehyde 19 by a similar procedure to that described from ethanol to aVord 1.58 g of 21 as white crystals. above, and the pure product was obtained by column chromam. p. 113 °C. Yield 47%. 1H NMR (CDCl3, TMS) d 0.87 (m, tography (silica gel, benzene; Rf=1.00, and alumina, chloro- 3H, CH3), 1.30 (m, 20H, CH2), 3.90 (t, J=6.0 Hz, 2H, form; Rf=1.00) and recrystallization from acetone. Purple OCH2), 6.67–7.50 (m, 8H, Ph). IR (KBr) nmax 2920, 2850 powder. Yield 33%. 1H NMR (CCl4, TMS) d -3.00 (broad, (CH2), 1600 cm-1 (Ph). 2H, NH), 0.90 (m, 12H, CH3), 1.30 (m, 80H, CH2), 4.13, 4.27 (t+t, 8H, OCH2), 7.30–7.80 (m, 6H, Ph), 9.07, 9.27 4-Formyl-4¾-dodecyloxybiphenyl (22).Under a nitrogen (d+d, 8H, porphyrin), 10.2 (s, 2H, meso-H). IR (film) nmax atmosphere, 1.6 M butyllithium solution in hexanes (2.6 ml, 3285 (NH), 2925, 2855 (CH2), 1505 (Ph), 1246 cm-1 (ROPh). 4.16 mmol) was added slowly to a solution of 21 (1.50 g, 4.09 mmol) in 30 ml of dry benzene and the mixture was 5,15-Bis(4-dodecyloxybiphenyl )porphyrin [8; (C12O)8- stirred for 30 min at room temperature.N,N- BBPH2]. The title compound was synthesized from 4-formyl- Dimethylformamide (DMF; 0.33 g, 4.50 mmol) in 5 ml of 4¾-dodecyloxybiphenyl 22 by a similar procedure to that benzene was added dropwise, and the reaction mixture was described above. However, because of the low solubility of stirred for 2 h at room temperature.The reaction was quenched this compound, the purification was accomplished in the by dilute hydrochloric acid, and the mixture was extracted following manner. The reaction mixture was concentrated, with diethyl ether. The organic layer was washed with water, and the residue was washed with tetrahydrofuran or dichlorodried over sodium sulfate, and concentrated. After column methane and Soxhlet extraction of impurities was performed chromatography (silica gel, benzene; Rf=0.58), 0.49 g of 22 with acetone–ethyl acetate.The residue was recrystallized from was obtained as a white solid. m.p. 87 °C. Yield 36%. 1H chloroform and dichloromethane to give a dark purple powder. NMR (CDCl3, TMS) d 0.70 (m, 3H, CH3), 1.10 (m, 20H, Yield 44%.IR (KBr) nmax 3260 (NH), 2930, 2860 (CH2), CH2), 3.73 (t, 2H, OCH2), 9.58 (s, 1H, CHO). IR (Nujol ) 1600, 1580 (Ph), 1245 cm-1 (ROPh). nmax 1680 cm-1 (CO). 5,15-Bis(3,4,3,4-tetradodecyloxy-o-terphenyl )porphyrin [4; Notes and references (C12O)8-BTPH2]. To a solution of aldehyde 17a (1.43 g, 1 K. Ohta, M. Ando and I. Yamamoto, J. Porphyrins 1.44 mmol) and 2,2¾-dipyrrylmethane44,45 (0.22 g, 1.50 mmol) Phthalocyanines, in press.in 250 ml of dichloromethane, were added seven drops of 2 M. R. Wasielewski, Chem. Rev., 1992, 92, 435; J. P. Collman, Acc. trifluoroacetic acid, and the solution was stirred for 15 h at Chem. Res., 1977, 10, 265; D. Gust and T. A. Moore, Top. Curr. Chem., 1991, 159, 103. room temperature. After p-chloranil (1.42 g, 5.78 mmol) was 3 B.Morgan and D. Dorphin, Struct. Bonding, 1987, 64, 115. added, the mixture was refluxed for 1 h. The reaction mixture 4 J. L. Sessler and K. A. Burrell, Top. Curr. Chem., 1992, 161, 177. was concentrated, and the residue was purified by column 5 For example: J. van Esch, M. F. M. Rocks and R. J. M. Nolte, chromatography (alumina, chloroform; Rf=1.00, benzene; J.Am. Chem. Soc., 1986, 108, 6093; G. A. Schick, I. C. Schreiman, Rf=1.00, carbon tetrachloride; Rf=0.00, and silica gel, chloro- R. W. Wagner, J. S. Lindsey and D. F. Bocian, ibid., 1989, 111, form; Rf=1.00) and recrystallization from ethyl acetate to 1344; J. T. Groves and R. Newmann, ibid., 1989, 111, 2900; B. A. Gregg, M. A. Fox and and A. J. Bard, Tetrahedron, 1989, give 0.48 g of 4 as a reddish brown solid.Yield 30%. 1H NMR 45, 4704. (CCl4, TMS) d -3.00 (broad, 2H, NH), 0.87 (m, 24H, CH3), 6 Y. Suda, K. Shigehara, A. Yamada, H. Matsuda, S. Okada, 1.23 (m, 160H, CH2), 3.50–4.13 (m, 16H, OCH2), 6.47–8.40 A. Masaki and H. Nakanishi, Proc. SPIE-Int. Soc. Opt. Eng., (m, 18H, Ph), 9.23 (s, 8H, porphyrin), 10.1 (s, 2H, meso-H). 1991, 1560 (Nonlinear Opt.Prop. Org. Mater. 4), 75. IR (film) nmax 3300 (NH), 2930, 2860 (CH2), 1610, 1590 (Ph), 7 J. W. Goodby, P. S. Robinson, B.-K. Teo and P. E. Cladis, Mol. 1250 cm-1 (ROPh). Cryst. Liq. Cryst., 1980, 56, 303. 8 B. A. Gregg, M. A. Fox and A. J. Bard, J. Chem. Soc., Chem. Commun., 1987, 1134; J. Am. Chem. Soc., 1989, 111, 3024. 5,15-Bis(3,4,3,4-tetrahexadecyloxy-o-terphenyl )porphyrin 9 B.A. Gregg, M. A. Fox and A. J. Bard, J. Phys. Chem., 1990, [5; (C16O)8-BTPH2]. The title compound was synthesized from 94, 1586. aldehyde 17c by a similar procedure to that described above, 10 P. G. Schouten, J. M. Warman, M. P. de Haas, M. A. Fox and and the pure product was obtained by column chromatography H.-L. Pan, Nature, 1991, 353, 736. (silica gel, chloroform; Rf=1.00, and alumina, chloroform; 11 P.Doppelt and S. Huille, New. J. Chem., 1990, 14, 607. 12 G. Morelli, G. Ricciardi and A. Roviello, Chem. Phys. Lett., 1991, Rf=1.00) and recrystallization from ethyl acetate and 185, 468; F. Lelj, G. Morelli, G. Ricciardi, A. Roviello and dichloromethane. Brown solid. Yield 57%. 1H NMR (CCl4, A. Sirigu, Liq. Cryst., 1992, 12, 941. TMS) d -2.90 (broad, 2H, NH), 0.87 (m, 24H, CH3), 1.30 13 Y.Shimizu, M. Miya, A. Nagata, K. Ohta, A. Matsumura, (m, 224H, CH2), 3.50–4.06 (m, 16H, OCH2), 6.67–8.30 (m, I. Yamamoto and S. Kusabayashi, Chem. Lett., 1991, 25; 8H, Ph), 9.10 (s, 8H, porphyrin), 10.0 (s, 2H, meso-H). IR Y. Shimizu, M. Miya, A. Nagata, K. Ohta, I. Yamamoto and (KBr) nmax 3280 (NH), 2930, 2860 (CH2), 1580 (Ph), S.Kusabayashi, Liq. Cryst., 1993, 14, 795. 14 Y. Shimizu, A. Ishikawa and S. Kusabayashi, Chem. Lett., 1986, 1245 cm-1 (ROPh). 1041. 15 T. Sakaguchi, Y. Shimizu, M. Miya, T. Fukumi, K. Ohta and 5,15-Bis(4,4-didodecyloxy-o-terphenyl )porphyrin [6; (C12- A. Nagata, Chem. Lett., 1992, 281. O)4-BTPH2]. The title compound was synthesized from alde- 16 R. Ramasseul, P. Maldivi, J.-C.Marchon, M. Taylor and hyde 17d by a similar procedure to that described above, and D. Guillon, Liq. Cryst., 1993, 13, 729. the pure product was obtained by column chromatography 17 D. W. Bruce, D. A. Dunmur, L. S. Santa and M. A. Wali, J. Mater. Chem., 1992, 2, 363. (silica gel, chloroform; Rf=1.00, and alumina, chloroform; J. Mater. Chem., 1998, 8, 2637–2650 264918 For example: C. Piechocki, J. Simon, A. Skoulios, D. Guillon and 34 G. Zerbi, R. Magni, M. Gussoni, K. H. Moritz, A. Bigotto and Dirlikov, J. Chem. Phys., 1981, 75, 3175. P. Weber, J. Am. Chem. Soc., 1982, 104, 5245. 35 H. L. Casal, H. H. Mantosh, D. G. Cameron and R. G. Snyder, 19 G. Wenz, Makromol. Chem. Rapid Commun., 1985, 6, 577. J. Chem. Phys., 1982, 77, 2825; G. Unger and N. Masic, J. Phys. 20 H. Strzelecka, C. Jallabert, M. Veber and J. Malthete, Mol. Cryst. Chem., 1985, 89, 1036. Liq. Cryst., 1988, 156, 347. 36 C. Almirante, G. Minoni and G. Zerbi, J. Phys. Chem., 1986, 21 G. W. Gray, B. Jones and F. Marson, J. Chem. Soc., 1957, 393. 90, 852. 22 A. D. Adler, F. R. Longo, J. D. Finarelli, J. Goldmacher, 37 M. Ray-Lafon and T. Hemida, Mol. Cryst. Liq. Cryst., 1990, 178, J. Assour and L. KorsakoV, J. Org. Chem., 1967, 32, 476. 33; W. K. Lee, P.A. Heiney, M. Ohba, J. N. Haseltine and 23 G. H. Barnett, M. F. Hudson and K. M. Smith, J. Chem. Soc., A. B. Smith III, Liq. Cryst., 1990, 8, 839; W. K. Lee, P. A. Heiney, Perkin Trans. 1, 1975, 1401. J. P. McCauley and A. B. Smith III, Mol. Cryst. Liq. Cryst., 1991, 24 A. D. Adler, F. R. Longo and V. Va� radi, Inorganic Synthesis, ed. 198, 273. F. Basolo, McGraw-Hill, New York, 1976, vol. 16, ch. 7, p. 214. 38 D. Chapman, Spectrochim. Acta, 1957, 11, 609; K. Ohta, 25 J. S. Manka and D. S. Lawrence, Tetrahedron Lett., 1989, 30, M. Yokoyama and H. Mikawa, Mol. Cryst. Liq. Cryst., 1981, 6989. 73, 205. 26 S. Seki and H. Suga, Kagaku Sosetsu, No. 5, Non-equilibrium states 39 R. G. Snyder, J. Chem. Phys., 1967, 47, 1316. and relaxation processes, 1974, ch. 9, p. 225. 40 H. Ema, Master Thesis, Shinshu University, Ueda, 1988. 27 N. Ando, Master Thesis, Shinshu University, Ueda, 1992. 41 H. Hasebe, Master Thesis, Shinshu University, Ueda, 1991. 28 M. Ando, Master Thesis, Shinshu University, Ueda, 1993. 42 K. Ohta, T. Watanabe, S. Tanaka, T. Fujimoto, I. Yamamoto, 29 C. Piechocki, J. Simon, J.-J. Andre�, D. Guillon, P. Petit, P. Bassoul, N. Kucharczyk and J. Simon, Liq. Cryst., 1991, 10, A. Skoulios and P. Weber, Chem. Phys. Lett., 1985, 122, 124. 357. 30 H. R. Kricheldorf and G. Schwarz, Polymer, 1990, 31, 481. 43 T. Watanabe, Master Thesis, Shinshu University, Ueda, 1990. 44 H. Rapoport and C. D. Willson, J. Am. Chem. Soc., 1962, 84, 630. 31 B. E. Powell, J. Cryst. Growth., 1973, 18, 307. 45 R. Chong, P. S. Clezy, A. J. Liepa and A. W. Nichol, Aust. 32 G. Lattermann and H. Ho� cker, Mol. Cryst. Liq. Cryst., 1986, 133, J. Chem., 1969, 22, 229. 245, and references therein. 33 K. Ohta, R. Higashi, M. Ikejima, I. Yamamoto and N. Kobayashi, J. Mater. Chem., 1998, 8, 1979. Paper 8/05715J 2650 J. Mater. Chem., 1998, 8, 2637&ndas