Interlocking frameworks. A consequence of enlarging spacers from 4-pyridinecarboxylate to 4-(4-pyridyl)benzoate

The crystallinity of evacuated framework polymer {[Cu(pyca)]·2H2O}α, pyca=4-pyridinecarboxylate, is preserved after removal of the interstitial solvent molecules. Staying with Cu2+ and enlarging the spacers from 4-pyridinecarboxylate to 4-(4-pyridyl)benzoate results in a sixfold interpenetrating diamondoid framework. This is composed of different extended arrays in a 4:2 ratio each individually composed of one of two geometric isomers of Cu (distorted octahedral and square pyramidal) found in the crystal.