Synthesis, optical and redox attributes of core-/bay-substituted thionated NDIs, PDIs and their diverse radical anions

Abstract

Organic radical anions due to their wide-ranging applications can offer an exciting platform to investigate their ease of generation, structure-stability correlation, color modulation, etc. Radical anions of core-/bay-substituted thionated arylene...

Chalcogen Atom Size: A Key Parameter in Modulating Carbonyl Compound Properties

“…This redshifting of λ max is also observed for the systematic increasing thionation of naphthalene diimides (NDIs; Figure 6b), which has been shown experimentally to be accompanied by a reduction of the π HOMO –π LUMO gap [13] . Due to the energetic lowering of the π LUMO (Figure 6b), the more thionated NDIs have a higher electron affinity and are more easily reduced, which has been shown experimentally to manifest in more positive electrochemical reduction potentials [13,14] .…”

“…[12] This redshifting of λ max is also observed for the systematic increasing thionation of naphthalene diimides (NDIs; Figure 6b), which has been shown experimentally to be accompanied by a reduction of the π HOMO -π LUMO gap. [13] Due to the energetic lowering of the π LUMO (Figure 6b), the more thionated NDIs have a higher electron affinity and are more easily reduced, which has been shown experimentally to manifest in more positive electrochemical reduction potentials. [13,14] The more positive reduction potentials associated with the introduction of the heavier chalcogen atoms in C=X groups can be applied to rationally design organic electronics and photovoltaic devices that facilitate efficient electron injection.…”

“…The different chemical properties of compounds containing thiocarbonyl (C=S) or selenocarbonyl (C=Se) groups compared to regular carbonyl (C=O) groups, has also useful applications in the fields of photo‐ and electrochemistry [12–15] . First of all, in the design of photosensitizers, one can make use of the smaller optical gap upon varying X in the C=X groups down Group 16.…”

“…Due to the smaller π HOMO –π LUMO energy gap ( vide supra ), unsaturated compounds containing C=X groups comprising the heavier chalcogens often encounter, experimentally, a redshift of the optical absorption maximum λ max of the π→π* transition (see Figure 6). [12–14] The redshift of the absorption upon changing X in C=X groups from O to S to Se can be particularly useful in designing new photosensitizers for phototherapeutic applications because of the deeper penetration of longer wavelength radiation into tissues [16] . For example, it has been shown before that S‐ and Se‐substituted nucleobases, such as guanine, have a good potency as chemotherapeutic agents because of their more advantageous absorption properties (see Figure 6a).…”

“…The different chemical properties of compounds containing thiocarbonyl (C=S) or selenocarbonyl (C=Se) groups compared to regular carbonyl (C=O) groups, has also useful applications in the fields of photo-and electrochemistry. [12][13][14][15] First of all, in the design of photosensitizers, one can make use of the smaller optical gap upon varying X in the C=X groups down Group 16. Due to the smaller π HOMO -π LUMO energy gap (vide supra), unsaturated compounds containing C=X groups comprising the heavier chalcogens often encounter, experimentally, a redshift of the optical absorption maximum λ max of the π!π* transition (see Figure 6).…”