Unprecedented μ-1,2-bis(monodentate) coordination mode of croconate dianion (C5O52−): Synthesis and crystal structures of manganese- and copper-based coordination polymers

►Croconate dianion presents a new μ-1,2-bis(monodentate) coordination mode. ►The new coordination mode leads to the formation of distorted honeycomb 2D sheets. ►BPP ligand promotes interpenetrated supramolecular structures. ►BPP ligand also extends the system dimensionality.