4,8,12,16-Tetra-tert-butyl-s-indaceno[1,2,3-cd:5,6,7-c‘d‘]diphenalene:  A Four-Stage Amphoteric Redox System

Abstract

A four-stage amphoteric redox hydrocarbon (5) containing two phenalenyl units was prepared. X-ray crystallography of 5 reveals a delocalized D 2 h structure, which is consistent with the presence of only five signals in the 1H NMR spectrum of 5 at −60 °C. The cyclic voltammogram of 5 exhibits four reversible redox waves with a small numerical sum (E 1 sum) of first oxidation (E 1 ox) and reduction (E 1 red) potentials. Four redox states of 5 were successfully generated from the neutral 5 and were characterized by NMR, ESR, and UV−vis−near-IR spectroscopies and theoretical calculations. These spectral data reveal that phenalenyl units play an important role in the high amphotericity of 5 and the stability of the redox states generated.

One-dimensional alkylate-bridged Würster’s blue-based diradical dications

“…8.2 Å) between the centers of two TMPD moieties estimated from the X-ray structure analysis. This suggests that an unpaired electron is not only localized on one TMPD unit, but to some degree delocalized on the other TMPD, similar to reported bisphenalenyl diradicaloids [33]. To determine the spin multiplicity of 1 2+ in the ground state, SQUID magnetometry for its powder sample at 5-350 K was conducted (Figure 3).…”

Phenalenyl‐Based Open‐Shell Polycyclic Aromatic Hydrocarbons

“…The tetra‐ tert ‐butyl derivative ( 10 ) was prepared in 16 steps from acenaphthene and isolated in pure form. Compound 10 gave very broad 1 H NMR signals in the aromatic region at room temperature, and upon cooling, progressive line sharpening was observed (Figure ) . This behavior is frequently observed for singlet biradical species.…”

Importance of unpaired electrons in organic electronics

“…For PBBTPD, g = 2.0021, while we were unable to resolve the hyperfine structure from the signal, we note that such resonances cannot be resolved in general with materials of biradicaloid character. The only exception was a measurement that was performed at elevated temperature . To determine the effect of oxidation and reduction, ESR measurements were also performed with PBBTPD doped separately with iodine and phenylhydrazine, and compared with absorption measurements.…”