Two Organic–Inorganic Hybrids Assembled by Carboxylate-Bridging Lanthanide-Substituted Polyoxometalate Dimers with Copper–ethylendiamine Cations

Abstract

Two new organic–inorganic hybrid carboxylate-bridging copper–lanthanide heterometallic polyoxotungstates K2[Cu(en)2(H2O)]2{[Cu(en)2]3[Ce(GeW11O39)(H2O)2]2(C2O4)}·11H2O (1) and K2 [Cu(en)2(H2O)]2{[Cu(en)2(H2O)]2[Tb(PW11O39)(CH3COO)(H2O)]2}·15H2O (2) (en = 1,2-ethylenediamine) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analyses and X-ray single-crystal diffraction. X-ray structural analyses reveal that 1 exhibits the 1D zigzag chain architecture formed by dimeric oxalate-bridging {[Cu(en)2]3[Ce(GeW11O39)(H2O)2]2(C2O4)}6− units and [Cu(en)2]2+ linkers whereas 2 displays a typical hybrid acetate-bridging dimeric structure [(α-PW11O39)Tb(H2O)(η2,μ-1,1)–CH3COO] 2 10− modified by [Cu(en)2(H2O)]2+ fragments. Notably, both contain 2:2-type carboxylate-bridging monolanthanide-substituted Keggin-type dimeric moieties and two types of organic ligands. 1 represents the rare 1D Cu–Ln heterometallic germanotungstate containing mixed ligands of en and oxalate whereas 2 represents the rare dimeric organic–inorganic hybrid Keggin-type phosphotungstate containing both Cu–Ln heterometals and mixed ligands of en and acetate. Two new organic–inorganic hybrid copper–lanthanide heterometallic polyoxotungstates containing mixed organic ligands of en and carboxylate were successfully separated under hydrothermal conditions. 1 exhibits the 1D zigzag chain architecture formed by dimeric oxalate-bridging {[Cu(en)2]3[Ce(GeW11O39)(H2O)2]2(C2O4)}6− units by [Cu(en)2]2+ linkers, whereas 2 displays a typical hybrid acetate-bridging dimeric structure [(α-PW11O39)Tb(H2O)(η2,μ-1,1)–CH3COO] 2 10− modified by [Cu(en)2(H2O)]2+ fragments.