Key points are not available for this paper at this time.
The connection of a dianionic 2, 2’-biimidazolate (biim2−) bridging unit to cis-Cr (N∩N) 23+ (N∩N is a chelating didentate ligand) or cis-Cr (N∩N∩N∩N) 3+ building blocks (N∩N∩N∩N is a chelating tetradentate ligand) produces heteroleptic pseudo-octahedral CrN6+ chromophores. Their reduced cationic charge is compatible with the subsequent complexation of trivalent lanthanides (Ln3+) to give d-f (N∩N) 2Cr (biim) nLn (3+n) + (n = 1–4), (N∩N) 2Cr (biim) Ln (Tp) 22+ and (N∩N∩N∩N) Cr (biim) Ln (Tp) 22+ adducts (Tp is tri (1H-pyrazol-1-yl) -λ4-borate). Moving from polyaromatic N∩N (1, 10 phenanthroline) to saturated N∩N∩N∩N polyamine (cyclam) receptors controls the photophysical properties and leads to tunable light conversion in the target heterometallic complexes when Eu (III) is exploited as the activator for downshifting and Er (III) as the activator for upconversion.
Chong et al. (2026) studied this question.