Self-assembled lamellar nanostructures of wholly aromatic rod-rod-type block molecules

Wholly aromatic rod-rod type di- and triblock molecules, oligo(ether sulfone)-b-oligo(ether ketone)s (OES-OEK), were synthesized to study a solid-state self-assembled nanostructure. The OES and OEK segments in the block molecules form segregated crystalline domains. The energy-filtering transmission electron microscopy images revealed that the di- and triblock OES-OEK co-oligomers formed lamellar nanostructures with a periodicity of approximately 9 and 13 nm, respectively. [structure: see text].     

Efficient methods for the preparation of alkyl-aryl and symmetrical or unsymmetrical dialkyl ethers between alcohols and phenols or two alcohols by oxidation-reduction condensation

Oxidation-reduction condensation via alkoxydiphenylphosphines (diphenylphosphinite esters) (1), generated in situ from chlorodiphenylphosphine (2) and alcohols, 2,6-dimethyl-1,4-benzoquinone (3), and phenols proceeds smoothly to afford alkyl-aryl ethers in good to high yields under neutral conditions. In a similar fashion, a new and efficient method for the preparation of symmetrical or unsymmetrical dialkyl ethers in good to high yields is established via tetrafluoro-1,4-benzoquinone (fluoranil) (4), alcohols, and 1 formed in situ from (n)BuLi-treated alcohols and 2. This method is applicable also to the etherification of chiral secondary or tertiary alcohols with retention or inversion of configurations. The inverted ethers are afforded by treating chiral alkoxydiphenylphosphines and achiral alcohols, while the reaction of achiral alkoxydiphenylphosphines and chiral alcohols forms retained ethers.     

Lactose-appended schizophyllan is a potential candidate as a hepatocyte-targeted antisense carrier

A schizophyllan (beta-1,3-glucan) derivative carrying lactose-appendages prepared by reductive amination can form stable macromolecular complexes with polynucleotides, shows excellent affinity with a lactose-binding lectin, and effectively mediates gene transfection into hepatocytes.     

Beta-1,3-glucan (schizophyllan) can act as a one-dimensional host for creation of novel poly(aniline) nanofiber structures

We here demonstrate the creation of novel poly(aniline) (PANI) nanofiber structures by a polymer wrapping method using schizophyllan (SPG). Mannose-modified SPG can also wrap PANIs to give nanofibers having a lectin affinity. This interaction is applicable to designing novel PANI/protein composites. The results establish that SPG can act as a novel "host" to assemble PANIs into one-dimensional superstructures. [reaction: see text]     

Single-walled carbon nanotubes acquire a specific lectin-affinity through supramolecular wrapping with lactose-appended schizophyllan

Single-walled carbon nanotubes can be entrapped within a helical superstructure composed of schizophyllan bearing lactoside-appendages to show an excellent water-solubility as well as a specific lectin-affinity.     

Block copolystyrene derivatives having flexible alkylsulfonated side chains and hydrophobic alkoxy chains as a proton exchange membrane for fuel cell application

A series of block copolystyrene derivatives, poly{[4‐(4‐sulfobutyloxy)styrene]_x‐block‐[4‐(n‐butoxystyrene)]_y} (PSBOS_x‐b‐PnBOS_y), containing a flexible alkylsufonated side chain and hydrophobic alkoxy chain with various ion exchange capacities (IECs) have been synthesized based on living anionic polymerization. The resulting crosslinked membranes were prepared using 4,4′‐methylene‐bis[2,6‐bis(hydroxyethyl)phenol] as the crosslinker in the presence of methanesulfonic acid. The crosslinked PSBOS_2.2‐b‐PnBOS₁ membrane with IEC of 2.89 mequiv g^?1 displays a high proton conductivity (0.01 S cm^?1) at 30% relative humidity and 80 °C, which is comparable to that of Nafion. The well‐developed phase separation and the continuous hydrophilic domains in the crosslinked PSBOS_2.2‐b‐PnBOS₁ membranes have been observed in a transmission electron microscope image. Moreover, the dynamic mechanical analysis measurement and Fenton's reagent testing show that the crosslinked PSBOS_x‐b‐PnBOS_y membranes have good mechanical properties and oxidative stability. These results indicate that the introduction of flexible alkylsulfonated side chains to the polystyrene main chains positively affect both the proton conductivity and oxidative stability. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

New and efficient catalysts for enantioselective borohydride reduction of ketones and imines

Optically active aldiminato cobalt(II) complexes have been found to catalyze the enantioselective reduction of ketones with sodium borohydride affording the corresponding optically active secondary alcohols in high chemical yields with high enantioselectivities. The enantioselective borohydride reduction is also applicable to not only C=O bonds in aromatic ketones but also to C=N bonds in aromatic imines.