The phosphorescent and magnetic properties of a novel radical and its salt derived from 2,3′-biimidazo[1,2-a]pyridin-2′-one radical

A novel neutral radical was synthesized from 2,3′-biimidazo[1,2-a]pyridin-2′-one radical via Cu(I) catalyzed ring-opening and carbon–carbon coupling reactions. The neutral radical (green-yellow phosphorescence) and its sulfate salt (blue phosphorescence) display obvious different phosphorescent colors, attributable to their different electronic structures, and stacking structures as demonstrated by powder X-ray diffraction patterns. The neutral radical itself exhibits weak antiferromagnetic property. The sulfate salt radical mainly presents diamagnetism between 58 K and 380 K owing to its dimeric structure, below 58 K, it reveals complex magnetic behavior.