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2015-10-19

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Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/159720

Pentanuclear 3d-4f heterometal complexes of MII3LnIII2 (M = Ni, Cu, Zn and Ln = Nd, Gd and Tb) combinations: syntheses, structures, magnetism and photoluminescence properties

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https://doi.org/10.1021/acs.inorgchem.5b01142

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A new family of pentanuclear 3d-4f heterometal complexes of general composition [LnIII2(MIIL)3(μ3-O)3H](ClO4)·xH2O (1-5) [Ln = Nd, M = Zn, 1; Nd, Ni, 2; Nd, Cu, 3; Gd, Cu, 4; Tb, Cu, 5] have been synthesized in moderate yields (50-60%) following a self-assembly reaction involving the hexadentate phenol-based ligand, viz., N,N-bis(2-hydroxy-3-methoxy-5-methylbenzyl)-N′,N′-diethylethylenediamine (H2L). Single-crystal X-ray diffraction analyses have been used to characterize these complexes. The compounds are all isostructural, having a 3-fold axis of symmetry that passes through the 4f metal centers. The [MIIL] units in these complexes are acting as bis-bidentate metalloligands and, together with μ3-oxido bridging ligands, complete the slightly distorted monocapped square antiprismatic nine-coordination environment around the 4f metal centers. The cationic complexes also contain a H+ ion that occupies the central position at the 3-fold axis. Magnetic properties of the copper(II) complexes (3-5) show a changeover from antiferromagnetic in 3 to ferromagnetic 3d-4f interactions in 4 and 5. For the isotropic CuII-GdIII compound 4, the simulation of magnetic data provides very weak Cu-Gd (J1 = 0.57 cm-1) and Gd-Gd exchange constants (J2 = 0.14 cm-1). Compound 4 is the only member of this triad, showing a tail of an out-of-phase signal in the ac susceptibility measurement. A large-spin ground state (S = 17/2) and a negative value of D (-0.12 cm-1) result in a very small barrier (8 cm-1) for this compound. Among the three NdIII2MII3 (M = ZnII, NiII, and CuII) complexes, only the ZnII analogue (1) displays an NIR luminescence due to the 4F3/2 → 4I11/2 transition in NdIII when excited at 290 nm. The rest of the compounds do not show such NdIII/TbIII-based emission. The paramagnetic CuII and NiII ions quench the fluorescence in 2-5 and thereby lower the population of the triplet state

Matèries

Metalls de terres rares, Propietats magnètiques, Luminescència, Lligands

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Rare earth metals, Magnetic properties, Luminescence, Ligands

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Articles publicats en revistes (Química Inorgànica i Orgànica)

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MAITY, Manoranjan, MAJEE, Mithun chandra, KUNDU, Sanchita, SAMANTA, Swarna kamal, SAÑUDO ZOTES, Eva carolina, GHOSH, Sanjib, CHAUDHURY, Muktimoy. Pentanuclear 3d-4f heterometal complexes of MII3LnIII2 (M = Ni, Cu, Zn and Ln = Nd, Gd and Tb) combinations: syntheses, structures, magnetism and photoluminescence properties. _Inorganic Chemistry_. 2015. Vol. 54, núm. 20, pàgs. 9715-9726. [consulta: 23 de gener de 2026]. ISSN: 0020-1669. [Disponible a: https://hdl.handle.net/2445/159720]

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