Surface Modification of High-Nuclearity Lanthanide Clusters:  Two Tetramers Constructed by Cage-Shaped {Dy₂₆} Clusters and Isonicotinate Linkers

By incorporation of NO₃^- ligands with trigonal planar geometry as surface modifiers into the lanthanide cluster core backbone to remarkably improve the dimension of cluster cores, two novel lanthanide cluster compounds, Dy₃₀I(μ₃-OH)₂₄(μ₃-O)₆(NO₃)₉(IN)₄₁(OH)₃(H₂O)₃₈ (1) and Dy₁₀₄I₄(μ₃-OH)₈₀(μ₃-O)₂₄(NO₃)₃₆(IN)₁₂₅(OH)₁₉(H₂O)₁₆₇ (2) (HIN = isonicotinic acid), have been obtained under hydrothermal conditions. Single-crystal X-ray diffraction shows that in both cluster compounds, the block blocks of [Dy₂₆(μ₃-OH)₂₀(μ₃-O)₆(NO₃)₉I]³⁶⁺, {Dy₂₆}, are the largest cage-shaped lanthanide cluster cores known. Compound 1 is the first tetramer based on the linkage of two different types of high-nuclearity lanthanide clusters and IN ligands, while compound 2 represents the first tetramer constructed by {Dy₂₆} clusters and IN linkers.