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Tunable LCST of PNIPAM–IL copolymers.

Novel polymerized ionic liquids having an organoboron unit were prepared for the purpose of selective lithium cation transport. Hydroboration polymerization of 1,3-diallylimidazolium bromide and subsequent anion exchange reaction with LiTFSI [lithium bis(trifluoromethylsulfonyl)imide] afforded the corresponding organoboron polymer electrolytes in 89−81% yield. The structure of polymers was supported by 1H and 11B NMR spectra. After the addition of an equimolar amount of LiTFSI toward the organoboron unit, an ionic conductivity of 3.74 × 10-5−1.93 × 10-5 S/cm was observed at 50 °C. The lithium transference number for these systems was 0.87−0.45 at 30 °C. This demonstrates that anion trapping of the organoboron unit works very effectively in IL-based matrices compared with polyether-type matrices.

A decade has passed since organoboron -conjugated systems highly extended through the empty p-orbital of the boron atom emerged as a new class of -conjugated materials. Making use of convenient hydroboration polymerization, a variety ofconjugated organoboron polymers exhibiting fluorescence emission, n-type electrochemical activity, electrical conductivity, third order non linear optical property, anion sensing ability is easily prepared. The organoboron -conjugated polymers having highly bulky substituent on the boron atom shows high stability under air and moisture and therefore, potentially useful for versatile applications.The design of electron deficient organoboron -systems led to observation of unique photophysical behavior such as extraordinary high third order non linear optical susceptibility, facilitation of p-d à transition, intramolecular charge transfer, unusually activated -conjugative interaction and so forth.In addition to boration polymerization methods, polycondensation using di-Grignard reagent, Sonogashira type polycondensation, polycondensation via tin-boron exchange are useful for synthesis of -conjugated organoboron polymers.

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Liquid state halide salts composed of imidazolium cations having allyl groups were prepared. Their ionic conductivity, viscosity, and thermal properties were investigated. Introduction of allyl group on N-position effectively suppressed the crystallization of the corresponding salts. 1,3-diallyl imidazolium halides therefore showed considerably lower viscosity and higher ionic conductivity than other halide salts.

A systematic study of the binding of carbohydrates by functionalized zinc porphyrins indicated that [5, 15-bis(8-quinolyl)porphyrinato]zinc(II) (1) showed marked affinity for octyl glucoside and mannoside in CHCl3 (−ΔG° = 4.5−6.3 kcal mol-1). Analysis of the complexation-induced shifts of the carbohydrate OH protons in the 1H NMR revealed that receptor 1 bound the 4-OH group of mannoside and glucoside by coordination to the zinc and the 6-OH and 3-OH groups by hydrogen bonding to the quinolyl nitrogen atoms. These NMR results and comparison of binding affinity with reference receptors and ligands indicated that receptor 1 recognized the trans,trans-1,2-dihydroxy-3-(hydroxymethyl) moiety of carbohydrates by the combination of Lewis acid (zinc) and Lewis bases (quinolyl nitrogens). Poor affinities of 1 to octyl galactosides and octyl 2-O-methyl-α-mannoside were ascribed to neighboring group effects, where a neighboring group in ligands not directly involved in the receptor−ligand interactions had considerable influence on the affinity through destabilizing the hydrogen-bonding-network(s) in the receptor−ligand complex. The circular dichroism induced in the porphyrin Soret band by complexation with the carbohydrates displayed characteristic patterns, which parallel the patterns of the complexation-induced shifts in the 1H NMR. The CD patterns sensitively reflected the receptor−ligand interaction modes, particularly ligand orientation and fluctuation in the complex. Variable-temperature CD revealed that glucoside was fluctuating on 1 while mannoside was rigidly fixed on 1 at room temperature. Addition of alcohols to CHCl3 suppressed the binding by 1, while addition of polar additives such as water, alcohols, phenols, and ethers assisted the binding by 3 and 4 (−ΔΔG° = 0.2−0.4 kcal mol-1) in a low concentration range (0−1.5 mol %).

Covalent modification of proteins exerts significant effects on their chemical properties and has important functional and regulatory consequences. We now report the identification and verification of an electrically-active form of modified proteins recognized by a group of small molecules commonly used to interact with DNA. This previously unreported property of proteins was initially discovered when the γ-ketoaldehydes were identified as a source of the proteins stained by the DNA intercalators. Using 1,4-butanedial, the simplest γ-ketoaldehyde, we characterized the structural and chemical criteria governing the recognition of the modified proteins by the DNA intercalators and identified Nε-pyrrolelysine as a key adduct. Unexpectedly, the pyrrolation conferred an electronegativity and electronic properties on the proteins that potentially constitute an electrical mimic to the DNA. In addition, we found that the pyrrolated proteins indeed triggered an autoimmune response and that the production of specific antibodies against the pyrrolated proteins was accelerated in human systemic lupus erythematosus. These findings and the apparent high abundance of Nε-pyrrolelysine in vivo suggest that protein pyrrolation could be an endogenous source of DNA mimic proteins, providing a possible link connecting protein turnover and immune disorders.