Adaptation of guest molecules: A simple system that amplifies the gentle perturbation of host lattices from nickel(II) to cobalt(II)

•A sensitive adaptation of guest water clusters was explored in two similar MOMs.•It all depends on the infinite water chains and the discrete tetrameric water clusters.•The differences between the Ni(II) and Co(II) centers are very slight, but enlarged.•The metal ions play a key role in the dehydration and rehydration of the complexes.•Magnetic studies afford a dominant antiferromagnetic coupling between the metal ions.

Two dinuclear complexes [Ni2(μ-bpym)(fum)2(H2O)6]·5H2O (1, bpym = 2,2′-bipyrimidine, fum = trans-fumarate) and [Co2(μ-bpym)(fum)2(H2O)6]·2H2O (2) were assembled from MCl2·6H2O (M = Ni, Co), 2,2′-bipyrimidine, and trans-fumaric acid at ambient temperature. In particular, compounds 1 and 2 adopt almost the same molecular structure, but 1 hosts an infinite water chain while 2 traps a discrete tetrameric water cluster. It would arise from the guest water aggregates and would depend on the very slight differences in the coordination chemistry of the Ni(II) and Co(II) centers. The significant influence of metal ions on the resulting structures and the reversible dehydration/rehydration of the complexes further detailed. Photoluminescence spectra of 1 and 2 in the solid state at room temperature were obtained and studied. Magnetic studies showed that both of 1 and 2 afforded a dominant antiferromagnetic coupling between the metal ions.

Graphical abstractSensitive adaptation of the guest water clusters included in two nearly the same MOMs, exhibited distinct rates of reversible dehydration–rehydration, which were afforded by the very slight differences between the cobalt(II) and nickel(II) centers.Figure optionsDownload full-size imageDownload as PowerPoint slide