Syntheses and Properties of (Nitronyl nitroxide)‐substituted Tri‐phenylamine ortho‐Bridged by Two Oxygen and Sulfur Atoms

Abstract

A nitronyl nitroxide unit (NN) was linked with a triphenylamine‐based condensed polycyclic skeleton DOTT to form a radical substituted donor NN‐DOTT. X‐ray crystal structure analysis demonstrated a flat bowl shape of the DOTT unit. EPR spectra showed the localization of electron spin on the NN unit. Chemical oxidation of the DOTT unit produced radical‐substituted radical cation salts NN‐DOTT+ ⋅ SbF6− and NN‐DOTT+ ⋅ FeBr4− that are stable under ambient conditions. The magnetic behavior of NN‐DOTT+ ⋅ SbF6− is characterized by the strong intramolecular ferromagnetic interaction between NN and DOTT+. The X‐ray structural analysis of NN‐DOTT+ ⋅ FeBr4− shows planar structure of DOTT and 1D mixed‐stack column of NN‐DOTT+ and FeBr4−. Magnetic measurements established that NN‐DOTT+ ⋅ FeBr4− undergoes magnetic phase transition into a weak ferromagnet at 7 K.

Overclocking Nitronyl Nitroxide Gold Derivatives in Cross‐Coupling Reactions

“…Some examples include Pd(0)‐catalysed cross‐coupling reactions of aryl halides with a nitronyl nitroxide‐2‐ide gold(I) complex (Figure 1A). [22–24] This reaction has paved the way for robust di‐ and triradicals with a high‐spin ground state [25–28] and even for air‐stable magnetically active graphene nanoribbons [29–31] …”

S,C,C- and O,C,C-Bridged Triarylamines and Their Persistent Radical Cations

“…The radical cations of bridged triphenylamine derivatives 1 – 3 ( 1 •+ – 3 •+ ), which contain dimethylmethylene or oxygen bridges, are among these rare examples (Figure ), − although 1 •+ is slightly unstable and dimerizes to form a dication diradicaloid . The introduction of a bridging unit at the ortho -position of triphenylamine has become increasingly popular as a principle for the design of precursors to generate stable radical cations − in which effective spin delocalization is achieved due to the virtually planar structure resulting from the structural constraint; however, the development of benchtop-stable para -unsubstituted triarylamine radical cations still remains a challenging task.…”

A fused polycyclic compound containing phenothiazine and diazapyrene skeletons with weak D–A interactions

“…1). 4 This is a rare example of π-extension of the PTZ unit with an aromatic ring connected at the 3-position, followed by double annulation at the 2- and 4-positions. The structure and properties of 1 were investigated by means of X-ray structural analyses, spectral and electrochemical measurements, and theoretical calculations, and the results indicate that the inherent electron-donating and electron-accepting abilities of the PTZ and DAP skeletons, respectively, are unexpectedly retained in the fused-ring system due to the unique conjugation topology.…”

“…1). 4–6 There are a few donor (D)–acceptor (A)-type fused-ring compounds with a PTZ framework and electron-deficient conjugating rings. 7 In sharp contrast, PTZ units are often connected to A-units with single bonds or conjugated bridges to obtain advanced functional materials, such as photo-emitters with thermally activated delayed emission or photo-induced charge-separating systems.…”