| Autor: |
Bourakhouadar H; Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany., Hempelmann J; Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan., van Leusen J; Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany., Drichel A; Chair of Inorganic Chemistry, University of Wuppertal, Gaußstraße 20, 42119 Wuppertal, Germany., Bayarjargal L; Institute of Geosciences, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany., Koldemir A; Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 30, 48149 Münster, Germany., Reimann MK; Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 30, 48149 Münster, Germany., Pöttgen R; Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstraße 30, 48149 Münster, Germany., Slabon A; Chair of Inorganic Chemistry, University of Wuppertal, Gaußstraße 20, 42119 Wuppertal, Germany., Corkett AJ; Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany., Dronskowski R; Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany. |
| Abstrakt: |
Two novel ternary air-stable transition-metal carbodiimides, MnHf(NCN) 3 and FeHf(NCN) 3 , were synthesized via solid-state metathesis using either ZnNCN or Na 2 NCN as the carbodiimide source and the corresponding binary metal chlorides. These two phases are the first examples of transition-metal carbodiimides with an AB (NCN) 3 composition, akin to ubiquitous AB O 3 perovskite oxides. The crystal structure of MnHf(NCN) 3 was determined and refined from powder X-ray diffraction (XRD) data in the non-centrosymmetric space group P 6 3 22 allowing for chirality, the assignment of which is supported by second-harmonic generation (SHG) measurements. FeHf(NCN) 3 was found to crystallize isotypically, and the presence of iron(II) in a high spin state was confirmed by 57 Fe Mößbauer spectroscopy. The structures are revealed to be NiAs-derived and can be described as a hexagonal stack of NCN 2- anions with metal cations occupying 2/3 of the octahedral voids. Both IR spectroscopic measurements and DFT calculations agree that the NCN 2- unit is a bent carbodiimide with C 2 v symmetry, necessary to account for the size difference present in such a vacancy-ordered structure. Magnetic studies reveal predominantly strong antiferromagnetic interactions but no long-range order between the paramagnetic Mn 2+ centers, likely due to the dilution of Mn 2+ over the octahedral sites or perhaps even due to some degree of magnetic frustration. The optical and electrochemical properties of MnHf(NCN) 3 were then studied, revealing a wide band gap of 3.04 eV and p-type behavior. |
