No abstract

Eight amylose tris(ethylcarbamate) (ATEC) samples ranging in the weight-average molar mass M(w) from 1.0 × 10(4) to 1.1 × 10(6) g mol(-1) and five amylose tris(n-hexylcarbamate) (ATHC) samples of which M(w) varies from 4.9 × 10(4) to 2.2 × 10(6) g mol(-1) have been prepared from enzymatically synthesized amylose samples having narrow dispersity indices and no branching. Small-angle angle X-ray scattering (SAXS), light scattering, viscometry, and infrared (IR) absorption measurements were carried out for their dilute solutions, that is, ATEC in tetrahydrofuran (THF), 2-methoxyethanol (2ME), methanol (MeOH), and ATHC in THF and 1-propanol (1PrOH) to determine M(w), particle scattering functions, intrinsic viscosities, and IR spectra. SAXS and viscosity measurements were also made on ATEC in d- and l-ethyl lactates. The data were analyzed in terms of the wormlike cylinder model to estimate the helix pitch (or contour length) per residue h and the Kuhn segment length λ(-1) (stiffness parameter, twice the persistence length). Both ATEC and ATHC have large λ(-1) in THF, that is, 33 and 75 nm, respectively, and smaller λ(-1) were obtained in alcohols, indicating that they have rigid helical conformation stabilized by intramolecular hydrogen bonds in THF. On the contrary, the helical structure estimated from the h value significantly depends on the alkyl side groups in a complex fashion, that is, h = 0.36 nm for ATEC, h = 0.29 nm for ATHC, and h = 0.26 nm for amylose tris(n-butylcarbamate) (ATBC). This is likely related to the bulkiness of side groups packed inside the amylosic helices. The solvent dependence of h, λ(-1), and the fraction f(hyd) of intramolecular hydrogen bonds for ATEC can be explained by a current model as is the case with ATBC [ Terao , K. ; Macromolecules 2010 , 43 , 1061 ], in which each contour point along the chain takes loose helical and rigid helical sequences independently.

A series of the bis(octaalkoxyphthalocyaninato)lutetium(III) complexes [(C n O) 8 Pc] 2 Lu (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 temperaturedependent electronic absorption spectroscopy techniques. It was found that each of the Lu complexes shows a special rectangular ordered columnar (Col ro ) mesophase and a normal hexagonal (Col h ) columnar mesophase. It was established that the special Col ro mesophase gave two different stacking distances (h t and h f ) which originate from both trampoline movement and rotation of the phthalocyanine disks.

Phthalocyanine (Pc)-based discotic liquid crystals could be prepared very rapidly by using our developed novel microwave-heating apparatus. It took only 10-20 min to synthesize these Pc metal complexes and metal-free Pc derivatives in an organic solvent (glycerin) by microwave irradiation, whereas it took 24-48 h to synthesize them by the conventional oil bath method. To our knowledge, it is the first example of metal-free Pc derivatives synthesized by microwave methods in an organic solvent. In the vast examples of Pc syntheses by conventional oil bath methods, the Pc metal complexes can be obtained in higher yields by "Template Effect" of the metal than the corresponding metal-free Pc derivatives. Therefore, we expected that the present Pc metal complexes (C n S) 8 PcCu (2) could be also prepared by microwave methods in higher yields than the metal-free Pc derivatives (C n S) 8 PcH 2 (1). Contrary to our expectation, the yields of the metal complexes (C n S) 8 PcCu (2) were lower than those of the metal-free derivatives (C n S) 8 PcH 2 (1). It is very interesting that this result by the microwave method is quite opposite to the results by conventional oil bath method. Hence, in this work we have focused our interest on the "Template Effect" in the syntheses of Pc derivatives by the microwave method in order to investigate the relationship between microwave heating and template effect. It is the first attempt in Pc syntheses by the microwave method.

No abstract