2d and 3d isophlorinoids synthesis structural characterization redox and electronic properties

Abstract

In general anti aromaticity has not gained significant attention mainly due to the lack ofstable 4n 960 systems In this regard a stable isophlorin and its expanded derivatives provide a hope to glance into the world of anti aromatic systems Unlike aromatic porphyrinoids its counterpart anti aromatic expanded isophlorinoids are not much celebrated molecules due to lack of straightforward synthetic strategies Apart from the structural similarity the electronic and redox properties of these 4n 960 and 4n 2 960 systems are found to be different with opposite ring current effects Core modified and expanded isophlorins have been characterized as stable 4n 960 macrocycles with characteristic electronic and redox properties those are not observed in aromatic systems Despite many efforts few strategies are reported to synthesise planar expanded isophlorins Although very successful at synthesizing large macrocycles these strategies add considerable synthetic steps and lack of ring current effects In thiscontext the synthesis of stable quintessential planar 4n 960 molecules is crucial not only to understand the electronic effects of 960 conjugation but also imperative to the development of novel materials for applications in molecular electronics During the attempted synthesis of expanded isophlorins using acetylene bridges instead of methine carbon a stable and neutral 4n 1 960 radical was discovered A detailed analysis was carried out to confirm the neutral radical nature of the macrocycle using various analytical techniques and computational studies Further the synthesis of novel 40 960 antiaromatic expanded core modified isophlorinoids and the diradicaloid nature of the oxidised dication molecules were studied The non covalent interaction between 40 960 isophlorin and fullerene was also studied in the solid state Finally a tetrapod 3D fully 960 conjugated molecular cage was synthesised using a simple acid catalysed reaction The X Ray crystallography analysis confirmed the tetrapod cage struc newline newline