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Porphyrin‐Based Air‐Stable Helical Radicals
Author(s) -
Kato Kenichi,
Furukawa Ko,
Mori Tadashi,
Osuka Atsuhiro
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705291
Subject(s) - radical , porphyrin , intramolecular force , chemistry , photochemistry , circular dichroism , monomer , molecule , antiferromagnetism , crystallography , stereochemistry , organic chemistry , polymer , condensed matter physics , physics
Stable helical radicals are promising multi‐functional molecules in light of intriguing magnetic and chiroptical properties. Attempts were made to extend diphenylmethyl‐fused Ni II porphyrin radical to helical system as the first air‐stable organic neutral helical radicals. Intramolecular Pd‐catalyzed twofold C−H arylation of methyl‐ or methoxy‐introduced meso ‐diphenylmethyl Ni II porphyrins gave a mixture of the target and rearranged radicals. Oxidative fusion reaction of meso ‐(bis(1‐naphthyl)methyl) Ni II porphyrins provided doubly fused Ni II porphyrin radicals. One of the helical radicals was separated into enantiomers that showed mirror‐image circular dichroism (CD) spectra up to 1300 nm. The helical dinaphthylmethyl‐fused Ni II porphyrin radical displayed solid‐state magnetic property mostly arising from monomeric radicals, different from the parent diphenylmethyl‐fused Ni II porphyrin radical that showed antiferromagnetic coupling due to π‐stacked pairing.