68317-83-9Relevant academic research and scientific papers
Charge Transfer in Covalently-Linked Porphyrin-Donor Complexes from Picosecond Transient Absorption Spectroscopy
Loppnow, Glen R.,Melamed, Dan,Hamilton, Andrew D.,Spiro, Thomas G.
, p. 8957 - 8968 (1993)
Octaalkyl free base porphyrins have been synthesized with covalently attached electron donors at a single meso position.Singlet-state lifetimes were determined from fluorescence quenching in three solvents and were found to be /= 1.5 ps for the N,N,N',N'
Ortho-lithiations reassessed: The advantages of deficiency catalysis in hydrocarbon media
Slocum,Reinscheld, Thomas K.,White, Christopher B.,Timmons, Michael D.,Shelton, Philip A.,Slocum, Matthew G.,Sandlin, Rebecca D.,Holland, Erica G.,Kusmic, Damir,Jennings, John A.,Tekin, Kristen C.,Nguyen, Quang,Bush, Steven J.,Keller, Julia M.,Whitley, Paul E.
, p. 1674 - 1686 (2013/05/08)
Hydrocarbon media based metalation procedures involving "deficiency catalysis" are described for the ortho-lithiation of anisole (A), p-chloroanisole (p-ClA), o-, m-, p-methylanisoles (o-, m-, p-MA), the three dimethoxybenzenes (DMB's), dimethylaniline (DMA), dimethybenzylamine (DMBA), m-methoxydimethylaniline (m-MeODMA), and tetramethyl-p-phenylenediamine (p-TMPDA). These procedures involve certain mechanistic considerations, which must be fine-tuned to maximize the extent of metalation (EoM). Our working hypothesis is that a controlled deoligomerization of the n-BuLi hexamer found in hydrocarbon media will afford a "sweet spot" of deoligomerization such that a maximally efficient metalation medium can be formed. In many cases, a substoichiometric ratio of equivalent TMEDA to n-BuLi is 0.1-0.2:1.0, but certain substrates suffer multiple sites of metalation under these conditions, so different promoted hydrocarbon media systems incorporating measured equivalents of an ether have been formulated. This paper represents the summary of our successful efforts to render ortho-lithiations safer, greener, and more atom-economical by use of hydrocarbon solvent media. EoM's of 11 of the 12 substrates under these atom-economical conditions range from 87 to 97%.
