The conjugation of organometallic complexes with dipeptides or nucleobases was used to design bioorganometallic compounds. The introduction of the chiral dipeptide chains into ferrocene as a reliable organometallic scaffold induces the conformational enantiomerization of the ferrocenyl moiety based on the chirality-organized structure, via intramolecular hydrogen bonding. The configuration and sequence of amino acids play an important role in the construction of the chirality-organized bio-inspired systems with controlled hydrogen bonds. The conjugation of organometallic complexes with nucleobases was also demonstrated to afford bioorganometallic conjugates. An interesting feature of bioorganometallic conjugates is their strong tendency to self-assemble through intermolecular hydrogen bonds between their uracil moieties, wherein hydrogen bonding patterns were found to depend on the direction of hydrogen bonding sites.

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In recent years, it has been revealed that light-harvesting systems (LHSs) are composed of beautifully aligned chlorophyll molecules; the regulated alignment of chlorophylls is responsible for the efficient and selective light-harvesting energy transfer processes in purple bacteria. This finding led to the construction of regularly arranged assemblies of functional dyes as a step toward fabricating artificial LHSs. While most researchers use molecular interactions such as covalent, coordination, and hydrogen bonds to produce dye assemblies, our approach involves guest-host interactions using an inorganic nanosheet as a host material. This short review presents the construction of a 2D dye assembly and its effective utilization in artificial light-harvesting applications. Owing to the highly stable and uniform 2D alignment of functional dyes on inorganic nanosheets, nearly 100% singlet-singlet energy transfer and efficient light-harvesting were achieved.

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Molecular imprinting is a template polymerization to prepare functional materials capable of molecular recognition. Molecularly imprinted polymers (MIPs) can be simply prepared by copolymerization of a template molecule conjugated with functional monomers and cross-linkers. These robust and affordable synthetic polymer receptors are expected to be alternatives to biomacromolecules such as antibodies and enzymes. MIPs bearing a single function have matured so far, whereas preparation of multi-functionalized MIPs is still problematic due to the simple preparation protocols. Recently, we have proposed a new strategy, post-imprinting modification (PIM), to introduce additional functionality into MIPs and/or to improve molecular recognition activity by post-polymerization modification within the imprinted cavities, which was inspired by post-translational modifications during biosynthesis of proteins. In this paper, we describe an overview of PIM-based multi-functional MIPs, and introduce desirable functions such as off/on switching of molecular recognition activity, fluorescent reporting function for the binding events, catalytic activity and photo-responsive activity.

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This paper describes the fabrication of transparent polymer films for use in light management technology. The materials are prepared using glutamide-based supramolecular gelation. The glutamides are characterized by three functional groups attached to a glutamic acid through amide bonds; therefore, effective intermolecular interactions promote the formation of nanofibrils, such as tubular and helical aggregates, based on highly ordered molecular stacking. The resultant structures induce different luminescent and circularly polarized luminescent behavior. This unique luminescent behavior can be observed in polymer composite blended with the glutamide. In this study, we also demonstrate the applications of a luminescent glutamide-blended polymer system in light management technology.

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The clear difference in molecular shape distinguishes 2D polymers (2DPs) from conventional polymers. However, 2DPs do not need to be featureless sheets. The sheet can be characterized by its internal structure (i.e. molecular structure). This is where rational organic synthesis can play a crucial role. The authors have explored the synthesis of 2DPs with internal order. Strategies based on topochemistry and dynamic bond formation were implemented for the construction of periodic 2D networks. This has led to promising results that include the first successful organic synthesis of free-standing 2DP sheets with periodic internal order. The feasibility of the lateral polymerization of 1D material was also demonstrated with several concrete examples, which has opened a new door for the synthesis of 2DPs with in-plane anisotropic order.

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A peptide derivative having the sequence based on the hydroxyapatite-binding peptide (HABP) and its dendritic oligomers were designed and synthesized. Their ability to lead to mineralization under body fluid (SBF) conditions was evaluated. The peptide HABP-C having a MLPHHGA sequence that is missing two cysteine groups necessary for intermolecular disulfide bond formation, induced calcium phosphate (CaP) deposition, which resulted from the formation of peptide-CaP hybrids having tape-like morphologies. The dendritic dimer and tetramer of HABP-C also induced formation of peptide-CaP hybrids having basically similar morphologies. Oligomerization of the HABP-C sequence did not affect the resulting morphology of the hybrids. On the other hand, the dendritic tetramer clearly accelerated the initial steps, i.e. the interaction between the peptides and CaP nanoparticles spontaneously formed in SBF, of the hybrids formation, which demonstrated that clusters of peptides affect their mineralization abilities.

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Hemagglutinin (HA) of the influenza virus binds to sialyloligosaccaride receptors on the cell surface in the first step of infection; therefore, inhibitors of the HA-receptor interaction have potential as anti-influenza drugs. We previously identified the HA-binding peptide s2, ARLPRTMVHPKPAQP, from random peptide libraries using phage-display technology. The N-stearoyl s2 peptide showed inhibitory activity against influenza virus infection. To obtain molecules with high affinity for HAs, truncated s2 peptides and dendrimers were designed in the present study. The affinity of dendrimers functionalized with the truncated peptide was higher than that of the full-length s2 peptide, especially a tetrameric dendrimer with ARLPR was more than 70-times more effective than the s2 peptide.

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We newly synthesized fatty acid-like amphiphiles that contain a glycine, diglycine, or triglycine residue, and investigated their hydrogen bonding modes. The FT-IR spectra of these amphiphiles showed a typical amide mode attributed to polyglycine II (PGII), which is called 3₁-helix in a broad sense. This mode was observed as a splitting band appearing at 1650 and 1640 cm⁻¹. On the other hand, we have already shown the amide modes attributed to a β-sheet structure. The amide I mode of the parallel β-sheet gave a single peak at more than 1630 cm⁻¹, whereas the antiparallel β-sheet absorbed at 1690 cm⁻¹ (weak) and 1630 cm⁻¹ (strong). The parallel β-sheet, antiparalle β-sheet, and PGII are possible structures for a small peptide such as tripeptide, and hence, the spectral chart of the three structures, demonstrated in this study, should be helpful to diagnose a secondary structure of small peptide-containing molecules.

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The synthesis of aromatic polyimide containing phosphorylcholine (PC) group was carried out by the co-polycondensation of a PC-containing diamine monomer and 3,5-bis(4-aminophenoxy)benzene with 4,4’-hexafluoroisopropylidene diphthalic anhydride (6FDA) followed by chemical imidization. The solubility of the polyimides decreased as the PC content increased, and the polyimides containing less than 50 mol% PC units were soluble in aprotic polar solvents such as N,N-dimethylformamide, dimethyl sulfoxide and N-methyl-2-pyrrolidone. The nanosheets were successfully fabricated from the PC-containing polyimides by spin coating using poly(vinyl alcohol) or Na alginate as a sacrificial layer, which exhibited a high adhesive strength. Large quantities of nanosheets were also fabricated by a laminating method. Fragmented nanosheets were successfully fabricated by homogenizing the nanosheets suspended in water for 10 min at 16000 rpm. Fragmented nanosheets could be dispersed in water and adhered to the surface of various substrates in a patchwork pattern. Good blood compatibility was observed on the polyimide-coated surfaces. Therefore, the nanosheets and fragmented nanosheets can be useful for biocompatible coating materials.

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To investigate the effect of calcium compound fine powders on the degradation behavior of biodegradable aliphatic polyesters, films were prepared by thermal kneading of a plastic matrix with a calcium compound fine powder, followed by hot-press molding. Three kinds of commercial biodegradable aliphatic polyesters [poly(L-lactic acid), polybutylene succinate adipate, and poly(butylene succinate-co-lactate)] were selected as the plastic matrix. Two kinds of calcium compound fine powders derived from scallop shells were used as the modifier. The resulting films were investigated by a hydrolysis test for 90 d and soil burial test for 360 d. The biodegradability of these films was examined by the time-course of weight loss, total organic carbon content, and the surface morphology, observed by SEM. Addition of calcium oxide fine powder as the modifier contributed significantly to accelerate the speed of degradation of commercial biodegradable aliphatic polyesters and to suppress the acidification of soil used as the medium.

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Flexible transparent electrodes were fabricated by line patterning of conductive inks consisting of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT/PSS) and ethylene glycol on PET films. The average values of thickness, sheet resistance (R_s), electrical conductivity, total light transmittance (TT), and haze of the flexible transparent electrodes in the range of PEDOT/PSS dispersion between 80~95 wt% were found to be 101 nm, 160 Ω/□, 630 S/cm, 95.5% and 1.3%, respectively. The standard deviations of in-plane distributions of R_s (av. 146 Ω/□) and TT (av. 93.5%) were 3.9 Ω/□ and 0.2%, respectively, indicating high uniformity with excellent electrical and optical properties as flexible transparent electrodes. Furthermore, a polymer dispersed liquid crystal (PDLC) display was fabricated using the flexible PEDOT/PSS transparent electrodes. It was found that the PDLC display successfully operated by the opaque/transparent change due to the scattering/non-scattering transition caused by the electric field applied through top and bottom PEDOT/PSS electrodes.

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This paper is describing the formation of laminated photocatalytic sheets and the effect of UV-light irradiation. A TiO₂/PVDF bilayer structure is compared with a TiO₂/SiO₂/PVDF trilayer structure. When irradiated for 1000 h with UV-light, the transmittance decreases in a bilayer structure sheets caused by a chalking effect of the PVDF layer. In the case of the trilayer structured sheets, however, the chalking of the PVDF layer is completely suppressed because of the SiO₂ barrier layer. In this study, because the process temperature is limited to 100°C due to thermal degradation of PVDF, the TiO₂ films include titanium chelate intermediates. These intermediates photopolymerize during the initial stage of UV-light irradiation and, as a result, TiO₂ films shrink and give stress to the interface between TiO₂ and PVDF. It is found that the SiO₂ barrier layer also functions as a stress compensation layer.

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The phenolic resins with rigid substituents were reacted with vinyl ether with a glycidyl group to produce new epoxy resins containing degradable acetal linkages (1 and 2). Glass-transition temperatures (T_g) of cured acetal linkage-containing epoxy resins 1 and 2 were 61°C and 45°C, respectively. Cured boards of acetal linkage-containing epoxy resins and conventional phenolic novolak epoxy resin 4 were prepared. Acetal linkage-containing epoxy resin 1 and 2 had higher charpy impact strength than the conventional phenolic novolak epoxy resin 4. Acetal linkage-containing epoxy resin 1 and 2 underwent smooth hydrolysis with the treatment with aqueous acid in THF at room temperature to give the corresponding phenolic resins in high yield.

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Polysiloxane random copolymers that contain quaternized imidazolium salts ([PImn]Cl) (n is the number of methylene groups) were obtained by the quaternization reaction of poly[dimethylsiloxane-ran-(3-chloropropylmethylsiloxane)] (P1) with imidazole derivatives having different lengths of alkyl chains (Imn) at the 1-position. The introduction ratio of imidazolium salts into P1 was estimated to be from 93 to 100 mol % from ¹H NMR analysis. The glass transition temperatures (T_gs) of [PImn]Cls were determined by differential scanning calorimetry (DSC). Of all the samples, [PIm5]Cl and [PIm6]Cl had the lowest T_g of 14°C which is 12–15 K lower than the T_g of polysiloxane homopolymer having quaternized imidazolium salts without polydimethylsiloxane units.

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Radical copolymerizations of styrene dimmer [2,4-diphenyl-1-butene (STD)] and styrene trimer [2,4,6-triphenyl-1-hexene (STT)], obtained through thermal degradation of polystyrene, with N-methylmaleimide (MMI), 4-acetoxyphenyl maleimide (APMI) or 4-hydroxyphenyl maleimide (HPMI) were carried out under various conditions to obtain new STD- and STT-based polymers for chemical recycling. The copolymerization of STD and MMI in THF or in bulk at 60°C resulted in high-molecular-weight alternating copolymers [poly(STD-co-MMI)] (M_n = 13,000~30,000) in moderate yields (60~75%). The copolymerization of STD and APMI in THF at 60°C resulted in relatively high-molecular-weight alternating copolymers [poly(STD-co-APMI)] (M_n = 12,000) in moderate yields (67%). The copolymerization of STD and HPMI in THF or in bulk at 60°C resulted in relatively high-molecular-weight alternating copolymers [poly(STD-co-HPMI)] (M_n = 16,000) in moderate yields (68%). The copolymerization of STT and MMI in THF or in bulk at 60°C also resulted in relatively high-molecular-weight alternating copolymers [poly(STT-co-MMI)] (M_n = 6,000~17,000) in lower yields (35~45%). The glass transition temperatures (T_g′s) of poly(STD-co-MMI) and poly(STT-co-MMI) were 237°C and 173°C, respectively. The T_g′s of poly(STD-co-APMI), and poly(STD-co-HPMI) were 212°C and 216°C, respectively. Thermal decomposition temperatures (T_d′s) of the all the STD-based copolymers were about 330°C, indicating high thermal stability of these copolymers.

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The adsorption of ions in liquid crystals (LCs) to the surfaces of polyimde films having benzene moieties was investigated by evaluating the decay curves of the charged voltage as a function of time in the open-circuit setting. The degree of the decay of the charged voltage of an LC cell decreased with increasing time of voltage application before the open-circuit period. The experimental result and the analysis with the model for decay of the charged voltage due to ions in the LC layer of the LC cell indicate that most of the adsorbed ions did not desorb from the surface of the polyimide films with increasing time of voltage application, and thus the adsorbed ions did not affect the decay of the charged voltage.

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