Multi-mode emission color tuning of dithieno[3,2-b:2′,3′-d]arsoles†
The electronic structures of dithienoarsoles, which were prepared through a facile and safe synthetic procedure, were tuned in multiple ways: structural modification of the π-conjugated system and reactions of the arsenic atom. Suzuki–Miyaura coupling reaction proceeded without coordination to the catalyst or oxidation during the reaction, though the lone pair of the arsenic atom was not protected. As a result, the emission color was successfully controlled. Moreover, oxidation and coordination of the arsenic atom effectively changed the electronic structures, resulting in emission color change. Theoretical calculations revealed that the LUMO levels were significantly lowered by oxidation and coordination. High air-stability and moderate coordination ability of a trivalent arsenic atom enabled various such transformations for emission color tuning.