Framework coordination chemistry; generalised entry into a new class of supramolecular compounds exemplified by the structures of [Mn2(ebpy)3(NO3)4]n[where ebpy =N,N′-ethylenebis(2-pyridone)] and [Er2(ebpyrr)3(NO3)6]n[where ebpyrr =N,N′-ethyienebis(2-pyrrolidone)]

Abstract
The ethylene-bridged bis(2-pyridone) ligand N,N′-ethylenebis(2-pyridone) and its bis(2-pyrrolidone) analogue react with manganese(II) nitrate and erbium(III) nitrate to form polymers containing 36-membered or 54-membered metallomacrocyclic rings, respectively; the 36-membered rings are linked to form a chain polymer and the 54-membered form contiguous two-dimensional sheets.