title: Synthesis, optical properties, and electronic structures of fully core-modified porphyrin dications and isophlorins.
abstract: The synthesis, structures, optical properties, and electronic structures of the tetraphenyltetrathiaporphyrin dication (S(4)TPP(2+), 6) and tetrakis(pentafluorophenyl)tetrathiaisophlorin (S(4)F(20)TPP, 7) are reported. S(4)TPP(2+) (6) and S(4)F(20)TPP (7) were synthesized by acid-catalyzed condensation of the corresponding hydroxylmethylthiophene, followed by oxidation. The electronic structures of S(4)TPP(2+) (6) and S(4)F(20)TPP (7) were analyzed by using UV/Vis-absorption spectroscopy and by magnetic circular dichroism (MCD) spectroscopy and the bands were assigned by using time-dependent density functional theory (TD-DFT) and ZINDO/s calculations. A red-shift of the Q bands of S(4)TPP(2+) (6) is observed relative to the spectra of tetraphenylporphyrins because a destabilization of the HOMO leads to a narrower HOMO-LUMO band-gap. Michl's perimeter model was used to assign the absorption bands and MCD spectra of S(4)F(20)TPP (7). Current-density maps and nucleus-independent chemical-shift (NICS) calculations of S(4)TPP(2+) (6) and of a model compound predict marked modification to the diamagnetic ring current, whilst nonaromatic character is predicted for S(4)F(20)TPP (7).
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Kon-no
authors.forename: John
authors.initials: J
authors.lastname: Mack
authors.forename: Nagao
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Suenaga
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoza
authors.forename: Teruo
authors.initials: T
authors.lastname: Shinmyozu