Ambient stable naphthalenediimide radical ions: synthesis by solvent-free, sonication, mechanical grinding or milling protocols

Abstract

Green synthetic routes to a library of twenty four diphosphonium substituted naphthalenediimide (NDI) radical ions [NDI(PR3)2]˙+ Br− (R = alkyl/aryl) with excellent yields and stability are reported.

Doubly zwitterionic, di-reduced, highly electron-rich, air-stable naphthalenediimides: redox-switchable islands of aromatic–antiaromatic states

“…Importantly, 3 2+ and 5 2+ revealed exceptionally low LUMO levels of –5.15 and –5.03 eV, respectively. Interestingly, the LUMO of 3 2+ is 0.25 eV lower than that of the ultra-electron deficient NDI dication,16 and establishes itself as the lowest LUMO arylenediimide to be reported to date. Thus, 3 2+ is one of the strongest electron acceptors to be isolated 14,16a,20,21…”

“…Subsequently, arylenediimide π-scaffolds11 like naphthalenediimide (NDI) and perylenediimide (PDI) attracted huge interest due to their ability to accept two-electrons (2e – ) 12–14. While the 1e – reduced NDI radical ion has been isolated,15,16 isolation of the highly electron-rich di-reduced NDI remains elusive (Scheme 1a). In an elegant synthetic development, the 2e – reduced PDI dianion has recently been isolated 14.…”

Recent Advances in Mechanochemical Organic Synthesis

“…Solvent-free mechanochemical conditions were also used in synthesis of reactive species. Synthesis of naphthalenediimide radical ions was achieved by milling of naphthalenediimides with trialkyl and triarylphosphines and Et 3 N base [79]. The ArS N reaction provides bistrialkyl(aryl)phosphonium naphthalenediimide radical anions which were isolated, and automated ball milling procedure was superior to manual grinding and sonication conditions.…”

Mechanical grinding method of multi-axis linkage for elliptic contour based on algebraic geometry

“…Therefore, the efficiency, error and surface quality of abrasive belt grinding are directly related to the width of abrasive band and the diameter of contact wheel. At the same time, grinding linear speed, feed speed, floating pressure and cutting line spacing have different effects on grinding efficiency and quality [11].…”