Probing the Influence of Alkyne Substitution on the Electronic and Magnetic Properties of Diindeno[1,2-b;1',2'-i]anthracenes.

To further the ability to manipulate the properties of open-shell molecules, logical and incremental modifications to molecular structure are key steps that provide fine-tuning of established diradicaloid scaffolds. We report the synthesis of an electronically "pure" diradicaloid based on a 2,6-anthroquinoidal core where the once necessary ethynyl "wings" are removed. Through the simplification of the overall electronic structure, the singlet-triplet energy gap increases by 0.3-0.4 kcal mol-1 in the reported diradicaloids while avoiding significant disruption to their optoelectronic properties.