π‐Stacking Modulates the Luminescence of [(dppz)Ni(Mes)Br] (dppz = dipyrido[3,2‐<i>a</i>:2′,3′‐<i>c</i>]phenazine, Mes = 2,4,6‐trimethylphenyl)

Abstract

Abstract The red colour of the novel organonickel complex [(dppz)Ni(Mes)Br] (dppz = dipyrido[3,2‐ a :2′,3′‐ c ]phenazine, Mes = 2,4,6‐trimethylphenyl) originates from long‐wavelength MLCT/L′LCT charge transfer bands. However, luminescence in dilute solution comes presumably from the 3 π‐π* (phenazine) excited state. The red‐shifted emission exhibited in concentrated solutions is assigned to dimers. In the solid state emission is quenched. The crystal structure reveals two different types of π‐π stacking along the crystallographic a axis.