3D lanthanide-transition-metal-organic frameworks constructed by two distinct tetranuclear units of cubane {Ln₄} and chair-like {Cu ₄} clusters

Three novel lanthanide(III)-copper(I) heterometallic coordination polymers, Ln₂Cu₂I₂(OH)₂(pca) ₂(na)₂ (Ln = Y 1, Er 2, Yb 3; pca = 2-pyrazinecarboxylic acid, na = nicotinic acid), have been synthesized under hydrothermal reactions. X-Ray crystal structure analyses reveal that 1-3 are isomorphous and crystallize in the monoclinic space group C2/c. Both compounds are constructed from two distinct secondary building units (SBUs) of cubane {Ln₄} and chair-like {Cu₄} clusters, and result in 3D hetero-Ln-TM frameworks with an unusual binodal net, which provides a good example for the construction of fascinating hetero-Ln-TM network by combining different types of metal clusters. Furthermore, the IR, TGA, PXRD, UV-vis spectra of 1-3 were also studied.