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Seven dinuclear Ln tetrazole-1-acetate complexes with 2,2′-bipyridine as coligand have been synthesized. They possess similar structures but different coordination geometries because of different peripheral anions (such as NO3− and Cl−) and the Ln contraction effect. DyIII complexes 5 and 6 both are single-molecule magnets. Ab initio calculations revealed that 6 possesses a more anisotropic DyIII ion in comparison to that in 5. The SmIII, EuIII, TbIII, and DyIII complexes exhibit strong visible emissions, whereas the YbIII complex shows near-infrared luminescence.
Three types of lanthanide complexes based on the tetrazole-1-acetic acid ligand and the 2,2′-bipyridine coligand were prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analyses; the formulas of these complexes are [Ln2(1-tza)4(NO3)2(2,2′-bipy)2] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5)), [Dy2(1-tza)4Cl2(2,2′-bipy)2] (6), and [Yb2(1-tza)4(NO3)2(2,2′-bipy)2] (7) (1-tza = tetrazole-1-acetate and 2,2′-bipy = 2,2′-bipyridine). They are dinuclear complexes possessing similar structures but different lanthanide(III) ion coordination geometries because of the distinction of peripheral anions (such as NO3– and Cl–) and the effect of lanthanide contraction. The variable-temperature magnetic susceptibilities of 1–6 were measured. Both DyIII complexes (5 and 6) display field-induced single-molecule magnet behaviors. Ab initio calculations revealed that the DyIII complex 6 possesses a more anisotropic DyIII ion in comparison to that in 5. The room-temperature photoluminescence spectra of SmIII (1), EuIII (2), TbIII (4), and DyIII (5 and 6) complexes exhibit strong characteristic emissions in the visible region, whereas the YbIII (7) complex shows near-infrared (NIR) luminescence.
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