Chiral Homobimetallic Palladium(II) Complexes Composed of Chirality-Organized Quinonediimines Bearing Amino Acid Moieties

The chirality-organized quinonediimine derivatives bearing amino acid moieties were demonstrated to react with 2 molar equiv. of Pd(OAc)₂, resulting in the formation of the chiral homobimetallic palladium(II) complexes. The crystal structures of the chiral conjugated complexes revealed the coordination of the quinonediimine nitrogen to a palladium center and a chiral propeller twist conformation of the π-conjugated backbone. The mirror image relationship of the CD signals around the quinonediimine moieties in acetonitrile was observed between l- and d-derivatives, indicating the preservation of the chirality-organized structures even in a solution.     

Surface Modification of Epoxy Resin with Silicone-containing Block Copolymers

In order to improve oil and water repellency, silicone-containing block copolymers, composed of methylmethacrylate (MMA), glycidylmethacrylate (GMA), and polydimethylsiloxanemethacrylate (SMA), were blended in an epoxy resin. It was expected that the low surface energy dimethylsiloxane segments would adsorb and orient at the exterior of the resin to make a thin surface phase and the glycidyl groups would mesh with the epoxy resin by primary bonding. The techniques of X-ray photoelectron spectroscopy (ESCA), dynamic contact angle (DCA) and peel strength measurements of pressure sensitive adhesives were used to characterize the modified epoxy resin surface phases. The amount of Si_2p obtained via angular dependent ESCA investigation in the near surface region of the modified resin increased with decreasing sampling depth. With an increase in modifier content, both the amount of Si_2p and O_1s also increased. Both advancing and receding contact angles for an aluminum plate coated with modified resin, measured by dipping into and out of water, increased with the addition of these modifiers. The peel strength of a pressure sensitive adhesive tape affixed to the modified epoxy resin decreased dramatically with increasing modifier content. It was found that these copolymers were good surface modifiers to improve oil and water repellency and that they acted as release agents.