The Radical Anion and Dianion of Benzo[3,4]cyclobuta[1,2-b]phenazine

Abstract

We present the reduction of two azaacenes (a benzo-[3,4]­cyclobuta­[1,2-b]­phenazine and a benzo­[3,4]­cyclobuta­[1,2-b]­naphtho­[2,3-i]­phenazine derivative), featuring a single cyclobutadiene unit, to their radical anions and dianions. The reduced species were produced using potassium naphthalenide in the presence of 18-crown-6 in THF. Crystal structures of the reduced representatives were obtained and their optoelectronic properties evaluated. Charging these 4n Hückel systems gives dianionic 4n + 2 π-electron systems with increased antiaromaticity, according to NICS(1.7) zz calculations, featuring unusually red-shifted absorption spectra.

Atomistic‐Level Effects of Noncovalent Interactions and Crystalline Packing for Organic Material Structural Integrity upon Exposure to Gamma Radiation

“…Wu et al . and Stanger state that partially resolved hyperfine coupling and asymmetric features paired with highly delocalized carbon‐centered radicals lead to this observed spectral feature [22,23] . Therefore, we presume the broad feature present in ( 4,4’‐bpe ) ⋅ ( 1,2‐C 6 H 6 O 2 ) is due to moderate‐to‐weak π–π stacking interactions and the intensity of this peak is dependent on the consistency/alignment of the interaction.…”

“…The intensities were normalized using the generalized reference intensity ratio method described by Bish and Post and Snyder. [22] All resulting powder patterns showed no evidence of peak broadening, suggesting the crystalline material did not degrade into poorly crystalline state. With the use of the internal standard the relative intensity ratio method was used to explore other changes in crystallinity associated with peak intensity.…”

“…The most intense peak observed for NaCl is located at 31.79° 2Θ whereas the major peaks associated with both the single component and cocrystalline samples reside between 10–30° 2Θ. The intensities were normalized using the generalized reference intensity ratio method described by Bish and Post and Snyder [22] …”

“…Wu et al and Stanger state that partially resolved hyperfine coupling and asymmetric features paired with highly delocalized carbon-centered radicals lead to this observed spectral feature. [22,23] Therefore, we presume the broad feature present in (4,4'-bpe) • (1,2-C 6 H 6 O 2 ) is due to moderate-to-weak π-π stacking interactions and the intensity of this peak is dependent on the consistency/alignment of the interaction. Additional features are present in the EPR spectra of the cocrystal compared to the single component system, but the decrease in crystallinity is equivalent (74.2 %) upon exposure to radiation in comparison to its single component (74.5 %).In the 1,3-C 6 H 6 O 2 single-component system, 1,3-C 6 H 6 O 2 is connected by hydrogen bonding to form a 2-D network with no additional secondary non-covalent interactions such as π-π stacking (Figure 3b -top).…”

Naphthalene diimide–Annulated Heterocyclic Acenes: Synthesis, Electrochemical and Semiconductor Properties and their Multifaceted Applications

“…[54] Wu et al focused on the reduction of two aza acenes, specifically benzo [3,4] cyclobuta [1,2-b] phenazine (13) and benzo [3,4]cyclobuta [1,2-b] naphtho [2,3-i] phenazine (14) derivatives, to their radical anions and dianions which can serve as models to investigate the structure and properties of charge carriers within transistors, providing insights into their behavior and potential use in electronic devices. [55] Not only nitogen, but the incorporation of boron into acenes also enhances their stability and introduces unique properties and functions. Boron's vacant p orbital gives boronbased acenes appealing features such as Lewis acidity, electronaccepting capability, stimuli-responsivity, and adjustable photophysical properties.…”