Incorporating distinct metal clusters to construct diversity of 3D pillared-layer lanthanide-transition-metal frameworks

Three novel 3D pillared-layer heterometallic lanthanide-transition-metal (hetero-Ln-TM) compounds, namely, Ln₂Cu₇I ₆(ina)₇(H₂O)₆·H₂O [ina = isonicotinic acid; Ln = Ce (1), Sm (2)] and Er₄(OH) ₄Cu₅I₄(ina)₆(na)(2,5-pdc)·0. 3H₂O (3; na = nicotinic acid, 2,5-pdc = 2,5-pyridinedicarboxylic acid), have been obtained by incorporating different metal clusters as building blocks under hydrothermal conditions. Compounds 1 and 2 are isostructural and consist of two distinct building units of dimeric [Ln₂(ina) ₆] cores and inorganic 2D [Cu₈I₇] _nⁿ⁺ layers based on the [Cu₃I₃] and [Cu₄I₃]⁺ clusters. Compound 3 is constructed from decanuclear [CU₁₀I₈]²⁺ clusters and inorganic 1D [Er₄(OH)₄]_n⁸ⁿ⁺ cluster chain-based layers, which represent the first example of a 3D hetero-Ln-TM constructed by the combination of two distinct types of metal cluster units of a 1D [Er₄(OH)₄]_n⁸ⁿ⁺ cluster polymer and a transition-metal cluster. It is interesting that decarboxylation occurred in the ortho position and 2,5-pdc^2- was partially transformed into na^- under hydrothermal conditions. Compounds 1-3 represent good examples of using different metal cluster units to construct fascinating 3D hetero-Ln-TM frameworks.