816454-79-2Relevant academic research and scientific papers
Meso-13C-labeled porphyrins for studies of ground-state hole transfer in multiporphyrin arrays
Thamyongkit, Patchanita,Muresan, Ana Z.,Diers, James R.,Holten, Dewey,Bocian, David F.,Lindsey, Jonathan S.
, p. 5207 - 5217 (2008/02/08)
(Chemical Equation Presented) Understanding electronic communication among interacting chromophores provides the foundation for a variety of applications. The ground-state electronic communication in diphenylethyne-linked zinc-porphyrin dyads has been investigated by a novel molecular design strategy that entails introduction of a 13C-atom (*) at specific sites of the porphyrins where there is substantial electron density in the relevant frontier (highest occupied) molecular orbital. The site of 13C substitution is at a meso-position, either the site of attachment of the linker (proximal, "P") or the site trans to the linker (distal, "D"). The substituents (R) at the non-linking meso-positions are mesityl, tridec-7-yl ("swallowtail"), or p-tolyl groups. Altogether five isotopically labeled porphyrin dyads have been prepared. The hole/electron-transfer properties of one-electron oxidized dyads have been examined by electron paramagnetic resonance (EPR) spectroscopy. The introduction of the meso-13C label provides a "clock" (via the hyperfine interactions) that allows investigation of a time scale for hole transfer that is 3-4 times shorter than that provided by the natural abundance 14N nuclei of the pyrrole nitrogen atoms. The EPR studies indicate that the hole transfer, which has been previously shown to be fast on the time scale of the 14N hyperfine clock (～220 ns), remains fast on the time scale of the 13C hyperfine clock (～50 ns).
Boron-complexation strategy for use with 1-acyldipyrromethanes
Muthukumaran, Kannan,Ptaszek, Marcin,Noll, Bruce,Scheidt, W. Robert,Lindsey, Jonathan S.
, p. 5354 - 5364 (2007/10/03)
1-Acyldipyrromethanes are important precursors in rational syntheses of diverse porphyrinic compounds. 1-Acyldipyrromethanes are difficult to purify, typically streaking upon chromatography and giving amorphous powders upon attempted crystallization. A solution to this problem has been achieved by reacting the 1-acyldipyrromethane with a dialkylboron triflate (e.g., Bu 2B-OTf or 9-BBN-OTf) to give the corresponding B,B-dialkyl-B-(1- acyldipyrromethane)boron(III) complex. The reaction is selective for a 1-acyldipyrromethane in the presence of a dipyrromethane. The 1-acyldipyrromethane-boron complexes are stable to routine handling, are soluble in common organic solvents, are hydrophobic, crystallize readily, and chromatograph without streaking. The 1-acyldipyrromethane can be liberated in high yield from the boron complex upon treatment with 1-pentanol. Alternatively, the 1-acyldipyrromethane-boron complex can be used in the formation of a trans-A2B2-porphyrin. In summary, the boron-complexation strategy has broad scope and greatly facilitates the isolation of 1-acyldipyrromethanes.
