Trends in Syntheses, Structures, and Properties for Three Series of Ammine Rare-Earth Metal Borohydrides, M(BH4)3·nNH3 (M = Y, Gd, and Dy)
| Autor: | Dorthe Bomholdt Ravnsbæk, Young-Su Lee, Morten B. Ley, Flemming Besenbacher, Radovan Černý, Young Whan Cho, Torben R. Jensen, Lars H. Jepsen, Jørgen Skibsted |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
chemistry.chemical_classification
Metal borohydride Inorganic chemistry ddc:500.2 Thermal treatment Crystal structure Hydrogen storage Coordination complex Inorganic Chemistry Solvent Metal Crystallography chemistry Powder diffraction visual_art Mechanochemistry visual_art.visual_art_medium Salt metathesis reaction Density functional theory Physical and Theoretical Chemistry |
| Zdroj: | Inorganic Chemistry Inorganic Chemistry, Vol. 54, No 15 (2015) pp. 7402-7414 Haarh Jepsen, L, Ley, M B, Cerny, R, Lee, Y-S, Cho, Y W, Ravnsbæk, D B, Besenbacher, F, Skibsted, J & Jensen, T R 2015, ' Trends in Syntheses, Structures, and Properties for Three Series of Ammine Rare-Earth Metal Borohydrides, M(BH4)3·nNH3 (M = Y, Gd, and Dy) ', Inorganic Chemistry, vol. 54, no. 15, pp. 7402-7414 . https://doi.org/10.1021/acs.inorgchem.5b00951 Jepsen, L H, Ley, M B, Černý, R, Lee, Y-S, Cho, Y W, Ravnsbæk, D, Besenbacher, F, Skibsted, J & Jensen, T R 2015, ' Trends in Syntheses, Structures, and Properties for Three Series of Ammine Rare-Earth Metal Borohydrides, M(BH 4 ) 3 · n NH 3 (M = Y, Gd, and Dy) ', Inorganic Chemistry, vol. 54, no. 15, pp. 7402-7414 . https://doi.org/10.1021/acs.inorgchem.5b00951 |
| ISSN: | 0020-1669 |
| DOI: | 10.1021/acs.inorgchem.5b00951 |
| Popis: | Fourteen solvent- and halide-free ammine rare-earth metal borohydrides M(BH4)3·nNH3, M = Y, Gd, Dy, n = 7, 6, 5, 4, 2, and 1, have been synthesized by a new approach, and their structures as well as chemical and physical properties are characterized. Extensive series of coordination complexes with systematic variation in the number of ligands are presented, as prepared by combined mechanochemistry, solvent-based methods, solid-gas reactions, and thermal treatment. This new synthesis approach may have a significant impact within inorganic coordination chemistry. Halide-free metal borohydrides have been synthesized by solvent-based metathesis reactions of LiBH4 and MCl3 (3:1), followed by reactions of M(BH4)3 with an excess of NH3 gas, yielding M(BH4)3·7NH3 (M = Y, Gd, and Dy). Crystal structure models for M(BH4)3·nNH3 are derived from a combination of powder X-ray diffraction (PXD), (11)B magic-angle spinning NMR, and density functional theory (DFT) calculations. The structures vary from two-dimensional layers (n = 1), one-dimensional chains (n = 2), molecular compounds (n = 4 and 5), to contain complex ions (n = 6 and 7). NH3 coordinates to the metal in all compounds, while BH4(-) has a flexible coordination, i.e., either as a terminal or bridging ligand or as a counterion. M(BH4)3·7NH3 releases ammonia stepwise by thermal treatment producing M(BH4)3·nNH3 (6, 5, and 4), whereas hydrogen is released for n ≤ 4. Detailed analysis of the dihydrogen bonds reveals new insight about the hydrogen elimination mechanism, which contradicts current hypotheses. Overall, the present work provides new general knowledge toward rational materials design and preparation along with limitations of PXD and DFT for analysis of structures with a significant degree of dynamics in the structures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|