Periodic Hybrid DFT Approach (Including Dispersion) to MgCl<sub>2</sub>-Supported Ziegler–Natta Catalysts. 2. Model Electron Donor Adsorption on MgCl<sub>2</sub> Crystal Surfaces
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Bibliographic record
Abstract
The adsorption of small probe molecules (H 2 O, NH 3 and EtOH) and the small model silane Me 2 Si(OMe) 2 on (104) and (110) surfaces of α-MgCl 2 have been studied using periodic DFT calculations including a classical correction (of the type f (R)/R 6 ) for dispersion. The results reveal that donors strongly stabilize both crystal surfaces relative to the bulk solid. Moreover, coordination of two donor molecules to the four-coordinate exposed Mg atom of MgCl 2 (110) causes this surface to become preferred over MgCl 2 (104) surface with only a single donor per exposed Mg. However, coverage also plays an important role. The model silane preferentially adsorbs in bidentate mode on MgCl 2 (110), provided that coverage is 0.5 or lower; at full coverage, there is not enough space for such an arrangement, and only a monodentate binding mode is obtained. Such coverage effects should be even more pronounced for the bulkier silanes used as external donors in real MgCl 2 -supported Ziegler–Natta systems, as tailored experiments seem to confirm.
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| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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