Solid-state transformation of the MOF [Ni-2(bipy)(1.5)(PDC)(2)(H2O)(2)]center dot 3.5H(2)O

The combination of non-centrosymmetric ligands and dipyridyl spacers produces a MOF that potentially can be porous with formula [Ni-2(bipy)(1.5)(PDC)(2)(H2O)(2)]center dot 3.5H(2)O (bipy = 4,4'-bipyridine and PDC = pyridine-2,5-dicarboxylate). Dehydration of this compound results in a new MOF in which the formation of additional bonds between the carboxylate groups of PDC and the metal ion has occurred. This solid-state transformation takes place with no significant changes in the coordination sphere of the metal ion, which is unusual for coordination polymers. Both compounds exhibit the same unprecedented topology where the connectivity between nodes is remarkably high.