title: Magnetic circular dichroism spectroscopy of N-confused porphyrin and its ionized forms.
abstract: N-Confused porphyrin (NCP) and its externally methylated variant (MeNCP) were investigated using UV-vis and magnetic circular dichrosim (MCD) spectroscopies. In addition to evaluating the spectroscopy of the neutral compounds, the acid/base chemistry of these macrocycles was examined by the same methods. NCP exhibits two tautomeric states depending on the polarity of the solvent, and their protonation/deprotonation chemistries also differ depending on solvent polarity. DFT and TDDFT calculations were employed to evaluate the observed spectroscopic changes. Using both experimental and calculated results, we were able to determine the sites of protonation/deprotonation for both tautomeric forms of NCP. Inspection of the MCD Faraday B terms for all of the macrocycles presented in this report showed that the ΔHOMO > ΔLUMO condition is maintained in all cases, and these observations were in good agreement with the DFT calculations.
authors.affiliation: Department of Chemistry, University of Akron , Akron, Ohio 44325-3601, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ziegler
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Erickson
authors.forename: Michael R
authors.initials: MR
authors.lastname: Dahlby
authors.forename: Michael R
authors.initials: MR
authors.lastname: Dalby
authors.forename: Victor N
authors.initials: VN
authors.lastname: Nemykin