Aerobic Epoxidation of Olefins Catalyzed by Electronegative Vanadyl Salen Complexes

Vanadyl salen complexes bearing electron-withdrawing substituents have been prepared and characterized. Systematic substitutions on the ancillary ligand have allowed V^(5+)/V^(4+) reduction potentials to be tuned over a range of approximately 500 mV. The complexes are catalysts for the aerobic epoxidation of cyclohexene; catalytic activity roughly increases with increasing V^(5+)/V^(4+) reduction potential. The mechanism likely involves oxygen transfer from intermediate hydroperoxides that are formed by radical-chain autoxidation

Hahahahaha, Duuuuude, Yeeessss!: A two-parameter characterization of stretchable words and the dynamics of mistypings and misspellings

Stretched words like \u27heellllp\u27 or \u27heyyyyy\u27 are a regular feature of spoken language, often used to emphasize or exaggerate the underlying meaning of the root word. While stretched words are rarely found in formal written language and dictionaries, they are prevalent within social media. In this paper, we examine the frequency distributions of \u27stretchable words\u27 found in roughly 100 billion tweets authored over an 8 year period. We introduce two central parameters, \u27balance\u27 and \u27stretch\u27, that capture their main characteristics, and explore their dynamics by creating visual tools we call \u27balance plots\u27 and \u27spelling trees\u27. We discuss how the tools and methods we develop here could be used to study the statistical patterns of mistypings and misspellings and be used as a basis for other linguistic research involving stretchable words, along with the potential applications in augmenting dictionaries, improving language processing, and in any area where sequence construction matters, such as genetics