An unprecedented triply interpenetrated chiral network of 'square-planar' metal centres from the self-assembly of copper(II) nitrate and 1,2-bis(4-pyridyl)ethyne

Copper(II) nitrate reacts with 1,2-bis(4-pyridyl)ethyne (bpethy) in ethanol to yield mixtures containing, beside to a one-dimensional ladder-like polymer, a networked [Cu(bpethy)(2)] species, with a triply interpenetrated chiral frame based on pseudo-square planar metal centres, showing a topology theoretically predicted but never observed before, and containing uncoordinated ligands as guest molecules.