jo9b01119_si_004.cif (284.41 kB)
Two-Step Transformation of Aliphatic Polyketones into π‑Conjugated Polyimines
dataset
posted on 2019-06-25, 00:00 authored by Yumehiro Manabe, Mitsuharu Uesaka, Tomoki Yoneda, Yasuhide InokumaThe
chemo- and stereo-selective two-step transformation of aliphatic
polyketones composed of 3,3-dimethylpentane-2,4-dione units was achieved
to generate π-conjugated polyimines. Upon treatment with hydrazine,
discrete oligoketones with 4–8 carbonyl groups afforded ethylene-bridged
oligoisopyrazoles in 80–89% yields. These oligoisopyrazoles
underwent stereoselective oxidation at the ethylene bridge to give
fully π-conjugated oligo(isopyrazole-3,5-diyl-trans-vinylene)s
in 73–87% yields. Oxidation of the oligoimines drastically
changed their absorption and metal-coordination behaviors. Finally,
this two-step transformation was applied to polydisperse polymers.
Imine formation proceeded almost quantitatively, even for longer polyketones,
including docosamer. Subsequent oxidation of the polyimines furnished
a virtually insoluble material that showed broad and red-shifted solid-state
absorption over the whole visible region resulting from extended π-conjugation.