Search results for "Lanthanide"
showing 10 items of 230 documents
Rational Design of Lanthanoid Single-Ion Magnets: Predictive Power of the Theoretical Models
2016
We report two new single‐ion magnets (SIMs) of a family of oxydiacetate lanthanide complexes with D3 symmetry to test the predictive capabilities of complete active space ab initio methods (CASSCF and CASPT2) and the semiempirical radial effective charge (REC) model. Comparison of the theoretical predictions of the energy levels, wave functions and magnetic properties with detailed spectroscopic and magnetic characterisation is used to critically discuss the limitations of these theoretical approaches. The need for spectroscopic information for a reliable description of the properties of lanthanide SIMs is emphasised. SPINMOL ERC-CoG-647301 DECRESIM MAT2014-56143-R CTQ2014-52758-P CTQ2011-2…
Elemental composition of sediments from a former silver mine in Freiberg/East Germany
1999
Abstract We have determined the contents of 48 elements in 11 representative sediments from a former Ag-mine in Freiberg/Sachsen. As analytical method the instrumental neutron activation analysis (INAA) was used without chemical preconcentration. Strongly varying compositions were observed for both the main and trace elements. Of particular interest were the high lanthanide and Th/U contents in these sediments.
Geochemical behaviour of rare earths in Vitis vinifera grafted onto different rootstocks and growing on several soils.
2014
The geochemical behaviour of lanthanides and yttrium (Rare Earth Elements, REEs) has been investigated mainly in geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. This behaviour is assessed according to features recorded in sequences of REE concentrations along the REE series normalised with respect to a reference material. In this study, the geochemical behaviour of REE was investigated in different parts of Vitis vinifera specimens grown off-soil, on soils of different nature and grafted onto several rootstocks in order to evaluate effects induced by these changes. The results indicated that ro…
Exploring the High-Temperature Frontier in Molecular Nanomagnets: From Lanthanides to Actinides.
2019
Molecular nanomagnets based on mononuclear metal complexes, also known as single-ion magnets (SIMs), are crossing challenging boundaries in molecular magnetism. From an experimental point of view, this class of magnetic molecules has expanded from lanthanoid complexes to both d-transition metal and actinoid complexes. From a theoretical point of view, more and more improved models have been developed, and we are now able not only to calculate the electronic structure of these systems on the basis of their molecular structures but also to unveil the role of vibrations in the magnetic relaxation processes, at least for lanthanoid and d-transition metal SIMs. This knowledge has allowed us to o…
Family of Isomeric CuII–LnIII (Ln = Gd, Tb, and Dy) Complexes Presenting Field-Induced Slow Relaxation of Magnetization Only for the Members Containi…
2020
The strategic design and synthesis of two isomeric CuII complexes, [CuLA] and [CuLB], of asymmetrically dicondensed N2O3-donor Schiff-base ligands (where H2LA and H2LB are N-salicylidene-N'-3-methoxysalicylidenepropane-1,2-diamine and N-3-methoxysalicylidene-N'-salicylidenepropane-1,2-diamine, respectively) have been accomplished via a convenient CuII template method. These two complexes have been used as metalloligands for the synthesis of three pairs of Cu-Ln isomeric complexes [CuL(μ-NO3)Ln(NO3)2(H2O)]·CH3CN (for complexes 1A-3A, L = LA, and for complexes 1B-3B, L = LB and Ln = Gd, Tb, and Dy, respectively), all of which have been characterized structurally. In all six isomorphous and is…
Two pyrazolylborate dysprosium(III) and neodymium(III) single ion magnets modeled by a Radial Effective Charge approach
2013
Abstract A Radial Effective Charge model based on a point charge approach is applied in order to study the magnetic behavior of two lanthanoid single ion magnets coordinated by pyrazole-based ligands that produce a D3h crystal field. We obtain the lowest-lying magnetic levels and the associated wave functions of Dy(H2BPzMe22)3 (1), and the tricapped NdTp3 (2), where H2BPzMe22 = dihydrobis(dimenthylpyrazolyl)borate and Tp = trispyrazolylborate. Results support the observed SMM behavior.
Solvent-modulation of the structure and dimensionality in lanthanoid-anilato coordination polymers.
2018
We show the key role that the size and shape of the solvent molecules may play in the dimensionality and structure of a series of lanthanoid–chloranilato coordination polymers. We report the synthesis, structure and magnetic properties of six different coordination polymers prepared with Er(III) and chloranilato (C6O4Cl22− = 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone) and six different solvents: [Er2(C6O4Cl2)3(H2O)6]·10H2O (1), [Er2(C6O4Cl2)3(FMA)6]·4FMA·2H2O (2) (FMA = formamide = NH2CHO), [Er2(C6O4Cl2)3(DMSO)4]·2DMSO·2H2O (3) (DMSO = dimethy sulfoxide = Me2SO), [Er2(C6O4Cl2)3(DMF)6] (4) (DMF = dimethylformamide = Me2NCHO), [Er2(C6O4Cl2)3(DMA)4] (5) (DMA = dimethylacetamide = Me2NC(Me)O) …
Two C3-symmetric Dy3 III complexes with triple di-μ-methoxo-μ-phenoxo bridges, magnetic ground state, and single-molecule magnetic behavior
2014
Two series of isostructural C3-symmetric Ln3 complexes Ln3·[BPh4] and Ln3·0. 33[Ln(NO3)6] (in which LnIII=Gd and Dy) have been prepared from an amino-bis(phenol) ligand. X-ray studies reveal that LnIII ions are connected by one μ2-phenoxo and two μ3-methoxo bridges, thus leading to a hexagonal bipyramidal Ln3O5 bridging core in which LnIII ions exhibit a biaugmented trigonal-prismatic geometry. Magnetic susceptibility studies and ab initio complete active space self-consistent field (CASSCF) calculations indicate that the magnetic coupling between the DyIII ions, which possess a high axial anisotropy in the ground state, is very weakly antiferromagnetic and mainly dipolar in nature. To redu…
The construction of open GdIII metal–organic frameworks based on methanetriacetic acid: New objects with an old ligand
2010
11 páginas, 11 figuras, 2 esquemas.-- et al.
Synthesis and Chemical physical characterization of a new series of hydroxil, acetylacetonate lanthanide (III) – ditungsten decacarbonyl hydride comp…
2004
A novel series of the heterometallic lanthanide(III) ionic cluster complexes of general formula Ln 9 (acac) 16 (OH) 10 [W 2 (CO) 10 (μ-H)] with Ln = Sm (la), Eu (1b), Gd (1c), Dy (1d), and Yb (le) was prepared and characterized by FTIR, 1 H NMR spectroscopy and single crystal X-ray analysis. The cluster series was obtained by reaction in ethanol solution of the 2,4-pentanedionate hydrate of lanthanide(III), Ln(acac) 3 .3H 2 O, with the hydridic ditungsten decacarbonyl, [W 2 (CO) 10 (μ-H)] - . X-ray analysis showed that the complexes la-le are isostructural. The complete structural characterization of the Eu derivative (1b) shows, similarly to their chromium derivative analogues, a square an…