Steric control of 4-connected network topology in hydrogen bonded coordination polymers

Abstract

Two 1D coordination polymers of copper(II) acetylenedicarboxylate, [Cu(O₂CCCCO₂)(C₅H₅N)₂(MeOH)] (1) and [Cu(O₂CCCCO₂)(Me₂C₅H₃N)₂(MeOH)]·MeOH (2), have been synthesised and structurally characterised by single crystal X-ray diffraction. In both cases the square pyramidal Cu^II atoms have trans coordinated pyridyl ligands and trans η¹ carboxylates in the equatorial sites with methanol occupying the apical position. The linear dicarboxylate ligand results in the formation of near linear coordination polymers. The polymeric chains in 1 form 2D hydrogen bonded (4,4) sheets whereas in 2 this topology is not possible, due to the extra steric bulk of the pyridine methyl groups, and a 3D hydrogen bonded network with CdSO₄ (cds) topology is formed in which the lattice methanol molecules are also incorporated into the hydrogen bonding bridges.