Aggregation-Induced Emission of Bis(imino)acenaphthene Zinc Complexes: Photophysical Tuning via Methylation of the Flanking Aryl Substituents
摘要:
Bis(imino)acenaphthene zinc complexes with methylated aryl substituents have been examined from the standpoint of their photoluminescent properties. Although complexes 1-4 proved to be nonemissive in solution, complexes 1 and 2 were found to emit via an aggregation-induced emission pathway. On the other hand, complexes 3 and 4 were found to be nonemissive in the solid state. Detailed crystallographic studies of complexes 1-4 provided valuable insights into the structural differences between the emissive (1 and 2) and nonemissive complexes (8 and 4), particularly with respect to their molecular Structures and crystal-packing environments. TD-DFT theoretical calculations were carried out and were found to support the hypothesis that the phosphorescent emissions of 1 and 2 are due to the existence of intermolecular pi-stacking interactions within the crystal lattices. Finally, a series of solvatomorphs of complexes 1 and 2 were synthesized and their emissive properties were studied.
that are direct precursors to augmented N-heterocycliccarbenes with a fixed cis geometry. Reduction of bis(imino)acenaphthene ligands with a LiAlH4/AlCl3 reagent mix initially produced the corresponding 1,2-diamines which, upon ring-closing reaction with triethyl orthoformate in acidic solution, gave the requisite ionic intermediates. Formation of the carbenes was then shown by preparation of selected