Near-infrared 2Eg → 4A2g luminescence from a molecular bis-(tris(carbene)borate)manganese(IV) complex

Abstract

The molecular bis-(tris(carbene)borate) manganese(IV) complex [{PhB(MeIm)$_3$}$_2$Mn](OTf)$_2$ shows $^2$E$_g$ → $^4$A$_{2g}$ luminescence at 828 nm in the solid state at 85 K; this wavelength is longer by approximately 100 nm than the wavelengths typically observed for manganese(IV) and chromium(III) doped solids and for molecular chromium(III) complexes. Weak luminescence is also observed from a LMCT excited state with an absorption maximum at 500 nm. This represents the first molecular manganese(IV) compound for which luminescence has been reported.