High‐Temperature Experimental and Theoretical Study of Magnetic Interactions in Diamond and Pseudo‐Diamond Frameworks Built up from Hexanuclear Tantalum Clusters
| Autor: | Pavica Planinić, Jérôme Cuny, Thierry Guizouarn, Stéphane Cordier, Berislav Perić, Régis Gautier |
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| Přispěvatelé: | Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Ministry of Science, Education and Sports of the Republic of Croatia (grant no. 098-0982904-2946), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2011 |
| Předmět: |
tantalum
02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences Catalysis Paramagnetism Tetragonal crystal system Cluster (physics) cluster compounds density functional calculations magnetic properties X-ray diffraction Heisenberg model Chemistry Organic Chemistry Diamond [CHIM.MATE]Chemical Sciences/Material chemistry General Chemistry 021001 nanoscience & nanotechnology Magnetic susceptibility 0104 chemical sciences Crystallography Octahedron X-ray crystallography engineering 0210 nano-technology |
| Zdroj: | Chemistry-A European Journal Chemistry-A European Journal, Wiley-VCH Verlag, 2011, 17 (22), pp.6263-71. ⟨10.1002/chem.201002332⟩ Chemistry-A European Journal, 2011, 17 (22), pp.6263-71. ⟨10.1002/chem.201002332⟩ |
| ISSN: | 1521-3765 0947-6539 |
| DOI: | 10.1002/chem.201002332 |
| Popis: | International audience; Magnetic interactions in solid-state tantalum cluster compounds have been evidenced by using magnetic susceptibility measurements and corroborated by broken-symmetry DFT calculations. The three selected compounds are based on [Ta(6)X(12)(H(2)O)(6)](3+) (X=Cl or/and Br) units with edge-bridged Ta(6) octahedral clusters. Although two of them crystallise in the tetragonal space group I4(1)/a, all compounds exhibit a similar arrangement of paramagnetic clusters related to the diamond structural framework (Fd ̅3m space group). Magnetic parameters were fitted by using the [5,4] Padé approximant of high-temperature series expansion of susceptibility for the Heisenberg model (S=1/2) in the diamond framework, assuming only nearest-neighbouring interactions. Such a model appropriately describes magnetic-susceptibility measurements at temperatures T>0.7|J|/k. The magnetic interaction parameter J between two [Ta(6)Cl(12)(H(2)O)(6)](3+) clusters is estimated to be -64.28(7) cm(-1) ; it has been enhanced by replacing several chlorine inner ligands with bromine ones (J=-123(3) cm(-1) for two [Ta(6)Br(7.7(1))Cl(4.3(1))(H(2)O)(6)](3+) clusters) and is strongest between two bromine [Ta(6)Br(12)(H(2)O)(6)](3+) clusters with a value of -155(1) cm(-1) . Broken-symmetry DFT calculations within spin-dimer analysis confirmed this trend. Those interactions can be explained on the basis of the overlap between singly occupied a(2u) orbitals localised on neighbouring clusters. |
| Databáze: | OpenAIRE |
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