We report the electrochemical anion storage properties of a group of molecular solids of polycyclic aromatic hydrocarbons (PAHs): coronene, perylene, and triphenylene. We discover an interesting trend of progressively lower potentials for these three molecular solids. Our DFT calculations reveal that the inserted PF 6 − anions preferably bind with the edge sites of the coronene molecules as opposed to being sandwiched between two coronene molecular planes. For smaller PAHs, the more edge sites in the solids may facilitate higher capacity values. However, small PAHs do face a greater challenge of dissolution in the nonaqueous electrolyte, which affects the cycling stability.
4‐Substituted‐1,2,4‐triazoline‐3,5‐diones have been used to synthesize a series of new polydienes by the “ene” reaction at ambient temperatures. The extent of chemical conversion can be varied widely and up to 93% of the diene‐repeating units of the parent polymer chain undergo reaction. Yields of the new polymers based on the reactant range from 90 to 95% at room temperature; their physical properties range from secondary crosslinking effects or elasticity at low degrees of conversion to rigid, amorphous polymers with high softening points at high degrees of conversion. The new polymers show a predictable correlation between the extent of conversion and the softening point. A similar correlation exists between the polarity of the new polymers and the extent of conversion. Polydienes with conversions to the extent of 45% or greater are soluble in aqueous solutions of sodium hydroxide and those with conversions of 60% or greater are soluble in aqueous sodium bicarbonate. Thus, in general, the new polymers (1) have higher Tg, (2) become increasingly polar, hence are soluble in polar solvents, and (3) possess a reasonably acidic proton, hence form salts. Bistriazolinediones result in room temperature crosslinking. A kinetic study with model compounds suggests that the rate of the reaction can be varied, depending on the electronic nature of the 4‐substituent.
4-Substituted 1,2,4-triazoline-3,5-diones were found to add to the a position of ß-diketones and /3-diketo esters, yielding both 1:1 and 2:1 adducts. The 1:1 adducts showed a dramatic stabilization of the enolic tautomer when compared to the original /3-dicarbonyl compounds as evidenced by a large increase in percent enol in all solvents. Kinetic studies support reaction through the 1,4-dipolar pathway involving triazolinedione and the enolic form of the 3-dicarbonyl compound. This reaction was also found to demonstrate a strong solvent dependency, hydrogen bonding solvents being rate enhancing. Kinetic investigations1 have shown 4-phenyl-1,2,4-triazoline-3,5-dione (PhTD) to be one of the most powerful dienophiles known. It is 103 times more reactive than tetracyanoethylene (TONE) and 2 X 103 567times more reactive than maleic anhydride. A significant result is the ability of PhTD to undergo reactions at room temperature, a factor which makes it an excellent dienophile for poorly reactive and unstable electrocyclic substrates. PhTD was treated with butadiene and cyclopentadiene by Cookson, Gilani, and Stevens2 to yield the (4 + 2) cycloaddition products. This led to extensive further research with ( 4+ 2) cycloadditions.3'8(1) W.
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