Chromium(III)-trisoxalate, a versatile building block for luminescent materials

Chromium(III)-trisoxalate, [Cr(ox)3]3− (ox=C2O42−), incorporated into polymeric networks of composition [NaCr(ox)3][MII(bpy)3] and [NaCr(ox)3][MIII(bpy)3]ClO4 (ox=C2O42−, bpy=2,2′-bipyridine, MII=Zn, Fe, Ru; MIII=Rh, Cr), results in interesting features ranging from phonon-assisted and resonant energy migration within the R1 line the 2E state to persistent spectral side-hole burning via the latter, and manifestations of specific nearest-neighbour π–π interactions between bipyridine and oxalate. - Highlights: ► We present the multifaceted photophysical behaviour of chromium(III)-tris-oxalate. ► We differentiate between phonon-assisted and resonant energy migration. ► Resonant energy migration results in spectral diffusion. ► Resonant energy transfer can be tuned via pressure dependant spectral overlap. ► π–π interactions with the second coordination sphere create specific spectroscopic sites.