TY - JOUR
T1 - Magnetic Circular Dichroism of Transition-Metal Complexes of Perfluorophenyl-N-Confused Porphyrins
T2 - Inverting Electronic Structure through a Proton
AU - Doble, Samantha
AU - Osinski, Allen J.
AU - Holland, Shelby M.
AU - Fisher, Julia M.
AU - Geier, G. Richard
AU - Belosludov, Rodion V.
AU - Ziegler, Christopher J.
AU - Nemykin, Victor N.
N1 - Funding Information:
C.J.Z. acknowledges the University of Akron for support of this research. Generous support from the NSF CHE-1464711, Minnesota Supercomputing Institute, NSERC, CFI, University of Manitoba, and WestGrid Canada to V.N.N. is greatly appreciated. A summer research fellowship for SMH was provided by the Miller-Cochran Fund, administered by Colgate University. R.V.B. is grateful for the support of the HITACHI SR16000-M1 supercomputing facility by the Computer Science Group and E-IMR center at the Institute for Materials Research, Tohoku University, Sendai.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/5/18
Y1 - 2017/5/18
N2 - Neutral and deprotonated anionic Ni(II), Pd(II), Cu(II), and Cu(III) complexes of tetrakis(perfluorophenyl)-N-confused porphyrin (PF-NCP) were prepared and investigated by UV-visible and magnetic circular dichroism (MCD) spectroscopies. As in the previously reported Ni(II) adduct of tetraphenyl N-confused porphyrin, we observe sign reverse (positive to negative intensities with increasing energy) features in the MCD spectra of the neutral Ni(II), Pd(II), and Cu(II) complexes of PF-NCP, which is indicative of rare ΔHOMO < ΔLUMO relationships. Upon deprotonation of Ni(II), Pd(II), and Cu(II) complexes, these features revert to those of more typical porphyrin MCD spectra consistent with a ΔHOMO > ΔLUMO condition. The Cu(III) PF-NCP complex shows features similar to those of the deprotonated divalent metal systems. Spectroscopic features in all target complexes as well as previously published metal-free and Ni(II) NCP systems were correlated with the density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. Calculation data are consistent with the tautomeric rearrangement of the electronic structures of NCP cores playing dominant roles, with smaller contribution from the central metal ions in the observed optical and magneto-optical properties. This is true for all described NCP systems to date, as they affect the stabilization/destabilization of the N-confused porphyrin-centered Gouterman orbitals.
AB - Neutral and deprotonated anionic Ni(II), Pd(II), Cu(II), and Cu(III) complexes of tetrakis(perfluorophenyl)-N-confused porphyrin (PF-NCP) were prepared and investigated by UV-visible and magnetic circular dichroism (MCD) spectroscopies. As in the previously reported Ni(II) adduct of tetraphenyl N-confused porphyrin, we observe sign reverse (positive to negative intensities with increasing energy) features in the MCD spectra of the neutral Ni(II), Pd(II), and Cu(II) complexes of PF-NCP, which is indicative of rare ΔHOMO < ΔLUMO relationships. Upon deprotonation of Ni(II), Pd(II), and Cu(II) complexes, these features revert to those of more typical porphyrin MCD spectra consistent with a ΔHOMO > ΔLUMO condition. The Cu(III) PF-NCP complex shows features similar to those of the deprotonated divalent metal systems. Spectroscopic features in all target complexes as well as previously published metal-free and Ni(II) NCP systems were correlated with the density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. Calculation data are consistent with the tautomeric rearrangement of the electronic structures of NCP cores playing dominant roles, with smaller contribution from the central metal ions in the observed optical and magneto-optical properties. This is true for all described NCP systems to date, as they affect the stabilization/destabilization of the N-confused porphyrin-centered Gouterman orbitals.
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U2 - 10.1021/acs.jpca.7b02908
DO - 10.1021/acs.jpca.7b02908
M3 - Article
C2 - 28475333
AN - SCOPUS:85020931901
VL - 121
SP - 3689
EP - 3698
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
SN - 1089-5639
IS - 19
ER -