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The formation of a metastable supercooled alkyl-π molecular liquid was prohibited by subtle alteration of the molecular structure., Metastable states of soft matters are extensively used in designing stimuli-responsive materials. However, the non-steady properties may obstruct consistent performance. Here we report an approach to eradicate the indistinguishable metastable supercooled state of functional molecular liquids (FMLs), which remains as a liquid for weeks or months before crystallizing, via rational molecular design. The phases (solid, kinetically stable liquid, and supercooled liquid) of a model FML, branched alkyl chain-substituted 9,10-diphenylanthracene (DPA), are found to be governed by subtle alterations of the molecular structure (alkyl-DPA ratio and bulkiness of the DPA unit). We thus outline molecular design principles to avoid supercooled FML formation. Moreover, we demonstrate a practical technique to rapidly discriminate supercooled FMLs (within 5 h) by accelerating their crystallization in differential scanning calorimetry heating via pre-annealing or relatively slow scanning.

first published on 29 Jun 2017, We have synthesised a series of phthalocyanine-based discotic liquid crystals, (m-CnOPhO)(8)PcCu (n = 1-20: 2a-o), and investigated their mesomorphism by using a polarizing optical microscope (POM), a differential scanning calorimeter (DSC) and a temperature-dependent small angle X-ray diffractometer. We found that each of the derivatives 2a-o shows mesomorphism. However, the mesomorphism of the (m-CnOPhO)(8)PcCu derivatives strongly depends on the alkoxy chain length (n). The mesomorphism of the short chain-substituted derivatives 2a-e for n = 1-5 is a flying-seed-like type induced by flip-flop of the peripheral bulky substituents, whereas the mesomorphism of the long chain-substituted derivatives 2j-o for n = 10-20 is a conventional molten alkyl chain type induced by melting of the long alkyl chains. The moderately long chain derivatives (2f-i) for n = 6-9 in between show both types of mesophases. The detailed temperature-dependent X-ray diffraction measurements were carried out for three representative derivatives, 2b (n = 2 for n = 1-5), 2h (n = 8 for n = 6-9), and 2o (n = 20 for n = 10-20). As a result, we revealed that the Col(ro)(P2m) mesophase in 2b (n = 2) gave a halo denoted as Halo(arom). at d congruent to 5.2 angstrom due to flip-flop of the bulky aromatic substituents, and that the Colho mesophase in 2o (n = 20) gave a halo denoted as Halo(alkyl) at d congruent to 4.6-4.8 angstrom due to melting of the long alkyl chains. Therefore, we can distinguish the type of mesophase from Halo(arom). and Halo(alkyl). Very interestingly, the (m-C8OPhO)(8)PcCu (2h) derivative having moderately long alkyl chains gave Halo(alkyl) at about 4.8 angstrom in the lower temperature mesophase of Col(ho), but Halo(arom). at about 5.2 angstrom in the higher temperature mesophase of Col(ro)(P2(1)/a). This means that melting of the alkyl chains induces the Col(ho) phase in the lower temperature region, but that flip-flop of the bulky aromatic substituents induces the Col(ro)(P2(1)/a) phase in the higher temperature region. This unusual reverse phase transition sequence from a higher symmetry of the Col(h) mesophase to a lower symmetry of the Col(r) mesophase on a heating stage is attributable to such a unique stepwise melting of these two different types of substituents. To the best of our knowledge, this mesogen (2h) is the first example switching mesomorphism from the molten alkyl chain type to the flying-seed-like type in a discotic liquid crystal., Article, JOURNAL OF MATERIALS CHEMISTRY C. 5(29):7297-7306 (2017)

We synthesized a novel series of flying-seed-like derivatives (3a–g) based on phthalocyaninato copper(II) (abbreviated as PcCu) substituted by bulky groups {PhO (a), (o-C1)PhO (b), (m-C1)PhO (c), (p-C1)PhO (d), [m,p-(C1)2]PhO (e), [m,m′-(C1)2]PhO (f), and [m,p,m′-(C1)3]PhO (g)} instead of using long alkyl chains, in order to investigate their mesomorphism. Their phase transition behaviour and the mesophase structures were established using a polarizing optical microscope, a differential scanning calorimeter, a thermogravimetry analyser and a temperature-dependent small angle X-ray diffractometer. It was demonstrated that (PhO)8PcCu (3a) and [(p-C1)PhO]8PcCu (3d) show no mesophase, whereas [(m-C1)PhO]8PcCu (3c), {[m,p-(C1)2]PhO}8PcCu (3e), {[m,m′-(C1)2]PhO}8PcCu (3f), and {[m,p,m′-(C1)3]PhO}8PcCu (3g) show various kinds of columnar mesophases of Colro(P21/a), Colro(P21/a), Colro(C2/m) and Coltet.o, respectively, while [(o-C1)PhO]8PcCu (3b) shows a monotropic Colro(P2m) mesophase. Thus, we revealed that mesomorphism could be induced by these novel bulky substituents instead of using long alkyl chains, and that the mesophase structures were greatly affected by the number and position of the methoxy groups. In particular, it is very interesting that the derivatives with methoxy group(s) at the meta position(s), namely, 3c, 3e, 3f and 3g, tend to show enantiotropic mesophase(s), whereas neither the derivative with no methoxy group, 3a, nor the derivative with a methoxy group at the para position, 3d, show a mesophase.

A series of the bis(octaalkoxyphthalocyaninato)lutetium(III) complexes [(CnO)8Pc]2Lu (n = 10, 12, 14, 16, 18) were synthesized. The mesomorphic behaviour was revealed by using polarization microscopy and DSC. The detailed mesophase structures were clarified by using temperature-dependent X-ray diffraction and temperature-dependent electronic absorption spectroscopy techniques. It was found that each of the Lu complexes shows a special rectangular ordered columnar (Colro) mesophase and a normal hexagonal (Colh) columnar mesophase. It was established that the special Colro mesophase gave two different stacking distances (ht and hf) which originate from both trampoline movement and rotation of the phthalocyanine disks.

Novel sandwich-type doubledecker and tripledecker cerium complexes, bis[5,15-bis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (2: [(CnO)4BPP]2Ce; n = 14), bis[5,10,15,20-tetrakis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (5: [(CnO)8TPP]2Ce; n = 8,10,12,14,16,18), and tris[5,10,15,20-tetrakis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (6: [(CnO)8TPP]3Ce2; n = 10), have been synthesized by using the corresponding metal free derivatives, 5,15-bis(3,4-dialkoxyphenyl)porphyrin (1: (CnO)4BPPH2) and 5,10,15,20-tetrakis[3,4-bis(octadecyloxy)phenyl]porphyrins (4: (CnO)8TPPH2) which were previously reported to show a discotic lamellar(DL) mesophase. The mesophase structures of all these sandwich-type cerium complexes have been characterized in detail by microscopic observation, DSC measurements and temperature-dependent X-ray diffraction studies. We have investigated the critical molecular structure changing from lamellar mesophase-showing porphyrins to columnar mesophase-showing ones. We found that these sandwich-type multideckers may exhibit a columnar mesophase, when the central core is substituted by more than twelve alkoxy chains.

A series of bis[octakis(alkylthio)phthalocyaninato]rare-earth-metal(III) discotic compounds, [(CnS)8Pc]2M (M = Eu(III), Tb(III), Lu(III); n = 8, 10, 12, 14, 16, 18), has been synthesized. The mesomorphic and supramolecular structures have been investigated by using differential scanning calorimetry, polarization microscopy and temperature-dependent X-ray diffraction techniques. From the X-ray diffraction and spectroscopic results, it was revealed that in each of the rare-earth compound classes, [(CnS)8Pc]2Eu (n = 10, 12), [(CnS)8Pc]2Tb (n = 10, 12, 14) and [(CnS)8Pc]2Lu (n = 10, 12), derivatives were found which displayed a novel unique pseudo-hexagonal mesophase.The temperature dependence of the one-dimensional intracolumnar charge carrier mobilities, Σμ1D, has been measured for [(C12S)8Pc]2Lu and [(C18S)8Pc]2Lu using the PR-TRMC (pulse-radiolysis time-resolved microwave conductivity) technique. The mobility values in both the K and D phases are more than an order of magnitude larger than found previously for [(C12O)8Pc]2Lu and are close to the maximum values ever found for discotic materials. The lack of a decrease in Σμ1D at the mesophase to isotropic liquid transition suggests that these compounds may represent the first liquid phase organic semiconducting materials.

Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel, Cn–Ni (n = 1–12), and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel, CnO–Ni(n = 1–12, 14, 16, 18), have been synthesized. Their mesomorphism, thermochromism, supramolecular structures and π-acceptor property have been investigated by using different scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry. From the X-ray diffraction and electronic spectral results, it was established that the CnO–Ni complexes for n≤10 exhibit two differently colored discotic lamellar (DL) mesophases whereas none of the Cn–Ni complexes has a mesophase, and that the thermochromism (brown → green) is attributable to a slow transformation from the Ni–Ni bonded dimers to the Ni–S bonded dimers.

A series of octakisalkylthiophthalocyanines, (CnS)8PcH2 (n = 8, 10, 12, 16), and their copper(II) complexes, (CnS)8PcCu (n = 8, 10, 12, 16), have been synthesized. Their mesomorphism and supramolecular structures have been investigated by using differential scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique and temperature-dependent electronic spectroscopy. From the X-ray diffraction and electronic spectral results, it was revealed that each of the compounds has a Dh mesophase in which columnar structures the molecules form a mixture of the parts of aggregated dimers and monomers. The shapes of dimers are discussed by exciton coupling theory (Kasha's rule).

An unidentified phase X of 1,4-dialkyl-1,4-diazoniabicyclo[2.2.2]octane dibromides reported by Nogami et al. in 1985 was reinvestigated by differential scanning calorimetry, polarizing microscopy and temperature-dependent X-ray diffraction. The X phase was thus established as a smectic tetragonal (ST) mesophase which shows spontaneous homeotropic alignment.

Ten novel columnar liquid crystals, [octakis(4-alkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 8 –M; n = 10, 12; M = Cu, Ni) and [octakis(3,4-dialkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 16 –M; n = 8, 10, 12; M = Cu, Ni), have been synthesized and characterized. It was found that the mesophase structures of (C n O) 8 –M are very sensitive to the central metal and closely related to the aggregate structures in the solution. The (C n O) 16 –M derivatives exhibit a D hd mesophase at lower temperatures and a D rd (C2/m) phase at higher temperatures. Thus, the mesophase with higher symmetry appears at lower temperatures for these (C n O) 16 –M derivatives. This is quite opposite to the general tendency for the higher symmetry mesophase to appear at higher temperatures. In order to further clarify the structures of both the mesophases and the aggregate in solutions, the electronic and magnetic circular dichromism (MCD) spectra were measured. The Q band of (C n O) 16 –M in n-hexane showed a wide Davidov splitting. It was proven that such a wide splitting of the Q band can be attributed to the formation of dimers. The dimerization was confirmed by vapor pressure osmometric (VPO) measurements in n-hexane solution. Furthermore, the spectrum of the thin film in the mesophase in the absence of solvent at room temperature was similar to that of then-hexane solution. From these electronic absorption spectra, MCD spectra, VPO measurements and temperature-dependent X-ray diffraction studies, it was clarified for (C n O) 16 –M that the dimer structure in n-hexane solution is closely related to those in the thermotropic mesophases.

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 (C 12 O) 16 -TTPH 2 (1) and (C 12 O) 16 -TTPCu (1-Cu) derivatives exhibit D h columnar mesophases, which are the first examples of meso-substituted porphyrin metal-free derivatives and copper complexes. Type 5 strip-like (C n O) 8 -BTPH 2 [4 (n=12), 5 (n=16)] derivatives having eight long chains at the 5,15-positions exhibit D rd columnar mesophases. On the other hand, the type 5 (C 12 O) 4 -BTPH 2 (6) derivative having four long chains exhibits discotic lamellar D L.rec1 and D L.rec2 mesophases which have a two-dimensional rectangular structure within the layer. The (C 12 O) 4 -BPPH 2 (7) type 6 derivative also shows a D L lamellar mesophase. Bruce et al. reported that type 3 rod-like porphyrin derivatives show calamitic mesophases of S B , S E and S E′ 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.

The critical molecular structure change from columnar to lamellar mesophases in bis(diphenylglyoximato)nickel(ii)-based complexes has been investigated. When the number of the long chains surrounding the core complex part was reduced from eight to four, the mesophase changes its structure from columnar Colhd to novel disk-like lamellar DL.rec(P2121). When the length of the four chains at the p-positions was fixed and the remaining four chains at m-positions were gradually made shorter, each of the complexes shows a columnar Colho mesophase. Surprisingly, even when the substituents at m-positions are methoxy or methyl groups, a columnar Colho mesophase is still observed. When the substituents at m-positions were OH groups, another novel disk-like lamellar DL.rec(P211) mesophase is observed. Hence, it can be shown that the critical molecular structure change from the columnar to lamellar mesophase occurs between methoxy and hydroxy groups at the m-position. In both of the two novel DL.rec mesophases in the present study, the core complex parts are parallel to the layers and the long chains are normal to both the layers and the core complex planes. Such a unique mesophase structure has not been previously observed. The synthesis of these complexes and the temperature-dependent X-ray structural analyses of the unique mesophases are reported.

This work reports on mesomorphic thermochromism caused by metal centres leading to visualization of van der Waals interactions. We succeeded in obtaining columnar liquid crystals exhibiting very interesting thermochromism by introduction of long chains into disk-like bis(glyoximato) d8 metal(ii) complexes. These long-chain-substituted NiII, PdII and PtII complexes, (CnO)8-M, containing one-dimensional metal chain change color according to the metal–metal stacking distance. With increasing temperature, the metal–metal distance increases leading to an enlargement of the band gap between the filled ndz2 valence band and the empty (n+1)pzconduction band of the central metal. Generally speaking, when mesomorphic materials are heated, the peripheral alkyl chains melt, whereas the central aromatic part remains rigid. Adjacent peripheral long chains tend to lie within the van der Waals radius at lower temperatures, which results in a shortening of the distance between the central d8 metals in the present (CnO)8-M systems. This ‘fastener effect’ of the van der Waals interaction of peripheral long chains is weakened with increasing temperature, leading to visible color changes due to the ndz2–(n+1)pz interaction in the central metal chain. The 4;mmol) and 85% potassium hydroxide (12.9 g, 185 mmol) were added and the mixture was stirred vigorously forca. 1 h and filtered to remove precipitates. 3,3′,4,4′-Tetradecyloxybenzil 5 (3.00 g, 2.83 mmol) was added to the filtrate and under a nitrogen atmosphere the mixture was refluxed with stirring for 12.5 h. To the hot reaction mixture was added potassium tetrachloroplatinate(ii) (0.64 g, 1.54 mmol) dissolved in a small amount of ethane-1,2-diol. Immediately the solution was neutralized with glacial acetic acid as confirmed by pH test paper. After neutralization, reflux was continued for more than 6 h during which dark green precipitates gradually appeared. After reflux, the hot reaction mixture was filtered and the dark green precipitate collected on filter paper. The product was dissolved in chloroform and the solvent evaporated to give dark green liquid crystals. Purification was carried out by column chromatography [silica gel, chloroform–benzene (1:1 v/v), Rf=0.70] and reprecipitation carried out by adding acetone to a hot solution of the product in chloroform to give dark green liquid crystals (0.37 g, yield: 10%).

Phthalocyanine compounds substituted with steric hindrance groups have been synthesized: octakis(2-ethyl-hexyl)phthalocyanine (1b) and bis[octakis(4-octadecyloxyphenyl)phthalocyaninato]lutetium(III) complex (2d). These compounds exhibit a wide temperature range of discotic liquid-crystalline properties. Each of these compounds shows a discotic tetragonal disordered columnar mesophase (Dtet.d) or a discotic plain rectangular disordered columnar mesophase [Drd(p2m)] with a lattice very close to tetragonal. This Drd(p2m) phase is a novel discotic mesophase that has not been reported to date. It was found that the introduction of the steric hindrance groups, 2-ethylhexyl (b) and 4-octadecyloxyphenyl (d), tend to induce the appearance of the Dtet.d phase.

We report that the long-alkoxy-chain substituted bis(β-diketonato)copper(II) complexes, bis[1-(4′-dodecyloxybiphenyl-4-yl)-3-alkylpropane-1, 3-dionato]copper(II)[alkyl substituent (R′): ethyl, n-propyl and n-butyl], show a nematic (N) phase. The methyl complex has a discotic rectangular ordered columnar (Dro) phase, as reported previously. Therefore, the change from the Dro phase to the N phase occurs with changing from R′= methyl to R′= ethyl groups. In order to obtain derivatives having a wider temperature range for the nematic phase, a homologous series of the bis[1-(4′-alkoxybiphenyl-4-yl)pentane-1,3-dionato]copper(II) complexes (alkoxy = CnH2n+ 1O; n= 6, 8, 10, 11, 14) have been synthesized for R′= ethyl. The derivative for n= 11 gave the widest range (ΔT= 16.1 °C). Furthermore, the nematic phase of these complexes was established as an optically positive uniaxial nematic phase. The mesomorphism of the corresponding ligands was also investigated.

Novel bis(phthalocyaninato)lutetium(III) complexes substituted with long n-alkyl chains have been synthesized. These complexes, 1a–c, show three kinds of discotic mesophase (Dhd, Dob.d, and DL). Also 1a–c display the three primary colours (red, green, blue) of electrochromism in their solutions. The solutions of oxidized species of 1a–c are nearly red, although those of conventional bis(phthalocyaninato)lutetium(III) complexes are orange.

We rapidly synthesized multi walled carbon nanotubes (MWCNTs) by calcination of granulated polystyrene with nickel nanoparticles having different average diameter (D-Ni = 10, 20, 50 or 90 nm) under nitrogen gas at a certain temperature and time (700 degrees C, 15 min or 800 degrees C, 10 min), using a domestic microwave oven in order to systematically investigate the influence of the diameter of nickel nanoparticles on the diameter of MWCNTs. The MWCNTs synthesized here were characterized by a transmission electron microscope, a Raman spectrophotometer and a wide angle X-ray diffractometer. We found that for the calcination condition of (800 degrees C, 10 min), a relationship between the outer diameter of the resulted carbon nanotubes (D-CNT) and the diameter of catalytic nickel nanoparticles (D-Ni) can be described as a linear function, D-CNT = 1.01D(Ni) + 14.79 nm with the correlation coefficient R = 0.99, and that for the calcination condition of 700 degrees C, 15 min, D-CNT = 1.12D(Ni) + 7.80 nm with R = 0.95. Thus, we revealed that when the diameter of the catalytic nickel nanoparticles (D-Ni) increases by 1 nm, the outer diameter of the obtained MWCNTs (D-CNT) increases by about 1 nm., Article, JOURNAL OF MATERIALS CHEMISTRY A. 2(8):2773-2780 (2014)

In our previous work, we synthesized a series of phthalocyanine-based flying-seed-like compounds, (nPh-PhO)(4)PcCu (n = 3, 2, 1 and 0 in nPh-PhO: a-d), and revealed that each of them shows a columnar liquid crystalline phase (Col(ho) or Col(rho)) from rt to an extremely high temperature near 500 degrees C. Thus, we could obtain columnar liquid crystalline phases for discotic compounds by using bulky substituents (a-d) instead of long alkyl chains. In order to further study the utility of these bulky substituents (a-d) on the induction of mesomorphism for other shaped molecules, we have synthesized novel flying-seed-like calamitic phenoxybenzoic acid derivatives, nPh-PhOBA (3a-d), and their Mitsubishi-Mark-shaped terbium complexes, (nPh-PhOBA)(3)Tb center dot mMeOH (4a-d), in this work. Very interestingly, the mesomorphism of the phenoxybenzoic aids derivatives nPh-PhOBA (n = 0-3) was induced to show a mesophase (M-x) only by the bulky substituent d (n = 0), whereas the mesomorphism of their corresponding terbium complexes (nPh-PhOBA)(3)Tb(III) (n = 0-3) was induced to show rectangular columnar (Col(r)) mesophases by the bulky substituents c and d (n = 1, 0). On the other hand, the mesomorphism of the PcCu complexes (nPh-PhOBA)(4)PcCu (n = 0-3) in our previous work was induced by all the bulky substituents a, b, c and d (n = 0-3). Thus, it becomes apparent that both calamitic and columnar mesomorphism can be induced by the substitution of bulky groups instead of long alkyl chains, and that the balance of the core size and the bulkiness of the substituents is very important to obtain mesomorphism in flying-seed-like compounds. We believe that this is a new guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains., Article, JOURNAL OF MATERIALS CHEMISTRY C. 1(34):5315-5321 (2013)

In order to obtain novel “flying-seed-like” liquid crystals, we have prepared a series of bulky group-substituted phthalocyanine derivatives without any long alkyl chains: tetra[4-(triphenylmethyl)-phenoxy]phthalocyaninato copper(II) (1a), tetra[4-(1,1-diphenylethyl)phenoxy]phthalocyaninato copper(II) (1b), tetra[4-(1-methyl-1-phenylethyl)phenoxy]phthalocyaninato copper(II) (1c), tetra[4-(tert-butyl)phenoxy]phthalocyaninato copper(II) (1d), and octa[4-(triphenylmethyl)phenoxy]phthalocyaninato copper(II) (4). We have established by using a polarizing optical microscope, a differential scanning calorimeter and a temperature-dependent small angle X-ray diffractometer that the Pc derivatives 1a–d, but not 4, show columnar mesomorphism from r.t. to the extremely high decomposition temperatures at 450–500 °C. Their mesomorphism originates from thermal fluctuations due to free rotation of the bulky substituents. Thus, we have systematically demonstrated for the first time that liquid crystals can be also obtained by a series of novel bulky substituents instead of conventional long alkyl chains. Hence, we will be able to obtain a wide variety of new liquid crystalline compounds by using these bulky substituents instead of long alkyl chains. Very interestingly, these are unprecedented guidelines to obtain liquid crystalline compounds.

We report a new class of liquid crystalline system exhibiting columnar mesophases, which are constructed by the hierarchical supramolecular self-organization of a rod-like diacetylene derivative as the primary building block. A series of 1,3-alkadiynyl-4-benzoic acids (mmDA) with different alkyl chain lengths (m = 8–16) were synthesized and their mesophase properties were investigated by differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction under temperature control. The mmDA exhibited three types of mesophases, i.e., a discotic lamellar phase, DL, and two columnar rectangular phases, Colrd and Colro, with disordered and ordered stacking structures of the mesogens in a column, respectively, depending on the length of the alkyl substituent and temperature. We have revealed that the columnar mesophase structures are constructed with the rod-like mmDA molecules as the starting building blocks by hierarchical self-organization. The hydrogen-bonded dimers of the carboxylic acid with a rigid framework are assembled to provide a disc-like mesogen unit, which consists of a π-stacked core-part and peripheral alkyl-chains. The discotic supramolecular mesogens further stack in ordered and disordered columnar structures, producing the Colro and Colrd mesophases, or in the layer DL mesophase. This is a rare example for the discotic mesophases using the rod-like diacetylenes with a non-branched molecular structure.

Two oligo(phenylenevinylene)s with cyanobiphenyl terminates were synthesized as non-covalent modifiers of single walled carbon nanotubes (SWNTs). The wrapping of SWNTs with synthesized oligomers enhanced the dispersibility in CHCl3 by the dissociation of SWNT bundle structures. It was found that the addition of oligomers caused self-organized precipitation from a homogeneous dispersed solution of SWNT complexes. The self-organized precipitates exhibited thermotropic liquid-crystalline properties.

In 1911, Vorlarnder reported liquid-crystalline properties of unique “flying-seed-like” alkali metal carboxylates. They are neither “rod-like” nor “disk-like”. Moreover, they have neither a rigid core nor flexible long chains. The molecular shapes are totally different from about 93000 general liquid crystalline compounds. These flying-seed-like liquid crystals have been forgotten for about 100 years. We revealed and established for the first time from precise microscopic observations and temperature-dependent X-ray diffraction studies that sodium diphenylacetate exhibits a hexagonal columnar mesophase, and that potassium diethylacetate and potassium dimethylacetate exhibit a smectic A mesophase. These “old and new” flying-seed-like liquid crystals will become a novel field of science.

The reactions of the ylide from the five-membered cyclic phosphonium salt 1 with methyl vinyl ketone, chalcone, and benzylidene acetone afforded cycloheptenyldiphenylphosphine oxides via a Michael-type reaction followed by an intramolecular Wittig reaction.

The synthesis of mesogenic triphenylene-based porphyrazine complexes bearing sixteen decyloxy side-chains is described; the widely extended core-system present leads to an enhanced stability of the mesophases formed by these complexes.

The chloro(diisopropylamino)phosphanylium cation [(Pri2N)(Cl)P]+[AlCl4]–1 reacts with prop-2-ynyl alcohols 2a–d to give prop-2-ynyl aminophosphonic chlorides 3a–d in good yield. Using cinnamyl alcohol and benzyl alcohol instead of 2a–d, the reactions of cation 1 afforded the corresponding aminophosphonic chlorides. In the, reaction of cation 1 with ethanol, however, no aminophosphonic chloride 8 could be isolated. The yields of these reactions were better when two equivalents of cation 1 were used. The reaction mechanisms are also discussed.

The long-alkoxy-chain substituted bis(glyoximato)nickel(II) complexes, bis[1,2-bis(3,4-di-n-alkoxyphenyl)ethanedione dioximato]nickel(II)(n-alkoxy =n-C8H17O1n-C12H25O), exhibit ‘mesomorphic thermochromism’ and solvatochromism. The effect of temperature and polarity of the solvent on electronic spectra of these complexes has been investigated. It was found that the thermochromism and the solvatochromism are due to the 3dz2–4pz interband transition, which is sensitive to the one-dimensional Ni–Ni stacking distance. This transition shifts to higher energy with increasing temperature. It is closely correlated to aggregation of these complexes both in the mesophase and in solution.

Reactions of α-chlorovinyl sulphones (1a and b) with the monosodium salt of diethyl malonate gave cyclopropanes (2a and b) in good yield. In contrast, 4,5-dihydrofuran-3-carboxylates (3a and b) were obtained in the reaction of compounds (1a and b) with the monosodium salt of ethyl acetoacetate. The formation mechanisms of these compounds are discussed.

The new compound, square-planar trans-bis-(1-p-n-octylphenylbutane-1,3-dionato)copper(II) has four polymorphs, C1(m.p. 96 °C), Ca(99 °C), Cm(108 °C), and Ch(109 °C); C1, Ca, and Cm exhibit double-melting behaviour.

Bis[1,2-bis(3′,4′-di-n-decyloxyphenyl)ethane-1,2-dithiol]nickel, the reduction potential of which is –0.06 V (vs. saturated calomel electrode in CH2Cl2), has a hexagonal disordered columnar mesophase (Dhd) at 84–112°C.

The disc-like compounds, 5,6,5′,6′,5″,6″,5‴,6‴-octadodecyltetrapyrazino[2,3-b:2′,3′-g:2″,3″-I:2‴,3‴-q]porphyrazine (C12PzH2) and the copper(II) complex (C12PzCu), which have now been synthesized, exhibit different columnar mesomorphism (Dhd for C12PzH2, Drd for C12PzCu).

It was found that the bis(β-diketonato)copper(II) complexes (2a,b) have discotic mesophases: (2a), D1 : 76.1–117.2 °C, D2; 117.2–141.6 °C and (2b), D: 82.5–173.3 °C, and that the corresponding β-diketone ligands (1a,b) have classical mesophases: (1a), smectic: 28.5–60.7 °C and (1b), smectic: 72.3–83.6 °C.

The title cyclic phosphonium salt (1) reacted with various aldehydes to give the phosphine oxides (2a–d) in good yield; these when treated with aldehydes in the presence of BuLi gave the alcohols (4a, b). The alcohol (4a) was easily converted into the 1,6-diene (5) by treatment of NaH in DMF. The stereoselectivities of these reactions are also described.

The bis[1,2-di(p-n-alkoxyphenyl)ethane-1,2-dithione]nickel complexes (4a) and (4b), novel disc-like complexes with four n-alkoxy side chains, exhibit a discotic mesophase.