Electromagnetic shields based on multilayer film structures

Bulletin of the Lebedev Physics Institute - Electrodeposited multilayer-film electromagnetic shields are very promising for protecting various devices due to high shielding efficiency and the...     

ChemInform Abstract: Iso‐Nitrous Acid: Spectral Frequencies and Possible Synthetic Pathways.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Synthesis,Redox and Optical Properties of Low‐Bandgap Platinum(II) Polyynes with 9‐Dicyanomethylene‐Substituted Fluorene Acceptors

In view of the strong electron‐withdrawing nature of the cyano substituent, a blue donor/acceptor‐type organometallic polymer (trans‐[—Pt(PBu₃)₂—C≡C—R—C≡C—]_n (R = 9‐dicyanomethylenefluorene‐2,7‐diyl)) was prepared in good yield by CuI‐catalyzed polymerization involving the dehydrohalogenating coupling of trans‐[Pt(PBu₃)₂Cl₂] and H—C≡C—R—C≡C—H. The thermal, redox and photoconducting properties of the polymer are reported. Electronic absorption studies indicate that it has a bandgap of 1.58 eV which is the lowest among any of the metal polyyne polymers reported in the literature. The derivatization of the polymer backbone with electron deficient dicyano‐substituted electron acceptor in the side chain is found to be effective to tune the bandgap of this class of materials while maintaining their solubility and processability.     

Synthesis of a diazacrown ether containing polymers and formation of complexes with alkaline earth metals

We report the synthesis of a polymer that contains the diaza‐18‐crown‐6 moiety on the polymer main chain. Metal containing polymers were obtained when the respective barium or strontium complexes were used as monomers. These polymers emitted greenish blue light in solution, and the metal had little influence on absorption and emission energies. In the solid state, the position of the emission peaks was different probably due to a different degree of aggregation.     

Synthesis and liquid crystal properties of bipyridine-containing aromatic polyamides

A series of novel aromatic polyamides containing 2,2′-bipyridine moiety were synthesized by polycondensation of 2,2′-bipyridine-5,5′-dicarboxylic acid ( 2 ) with various aromatic diamines in hexamethylphosphoramide (HMPA) containing lithium chloride. The resulting polyamide solutions in 98% sulfuric acid and in HMPA-LiCl exhibited lyotropic liquid crystal phases. The phase transition behaviors were studied by polarizing microscopy and X-ray diffraction. The polyamides also formed metal complexes with cis-dichlorobis(bipyridine)ruthenium dihydrate [cis-Ru(bpy)₂Cl₂ · 2H₂O] which was supported by changes in electronic spectra.