Towards In‐Plane Delocalized 4N/7e Radical Cations and 4N/6e Dications – One‐/Two‐Electron Oxidation of Proximate‐Parallel Bis(N,N'‐bicyclic)‐bishydrazines

Abstract

AbstractIn the pursuit of novel bishomoconjugated (σ‐bishomoaromatic) 4N/7(6)e bonding motifs, (bisseco)pagodane/isopagodane and dodecahedrane‐like, caged, proximate‐parallel bishydrazines have been designed as suitable host skeletons. The derived radical cations and dications are characterized by calculations as cyclically in‐plane delocalized (σ‐bishomoaromatic) species (4N/7(6)e). However, the synthetic approaches based on a pool of half‐caged proximate‐parallel bisdiazenes/bishydrazines and on strategies in part elaborated in the pagodane area have not led to the target structures. Half‐caged, rather flexible bis(N,N'‐bicyclic) bishydrazines (9,10) evolved as the structurally closest synthetically accessible model compounds. Whilst CV (PE, ESR)measurements were not suggestive of significant through‐space interaction in the respective radical cations and dications, DFT calculations (B3LYP/6‐31G*) identified a singlet dication (102+) as proximate, cyclically in‐plane delocalized species, which, however, relaxed into a more stable, more distant triplet. In an Appendix, selected examples are presented for the synthetic utilization of proximate‐parallel bisdiazenes (bishydrazines) in the area of more or less preorganized, semi‐ to fully caged tetra(hexa)azapolycyclic molecules. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)