bei Google ScholarTitelangaben
Senker, Jürgen ; Sehnert, Jan ; Correll, Sascha:
Microscopic Description of the Polyamorphic Phases of Triphenyl Phosphite by Means of Multidimensional Solid-State NMR Spectroscopy.
In: Journal of the American Chemical Society.
Bd. 127
(2005)
Heft 1
.
- S. 337-349.
ISSN 1520-5126
DOI: https://doi.org/10.1021/ja046602q
Abstract
The structural properties of a second, apparently amorphous phase (aII) of the molecular glass former triphenyl phosphite were studied by means of multidimensional solid-state NMR spectroscopy and X-ray diffraction. Phase aII was prepared by annealing the supercooled liquid in the temperature range 210 K ≤ Ta ≤ 230 K. In addition to 1D 1H and 31P spectra and spin−lattice relaxation data, we used 31P radio-frequency-driven spin-diffusion exchange spectroscopy to analyze the arrangement of neighboring TPP molecules on both a local and intermediate scale. For the first time, our results give a detailed microscopic description of phase aII. For Ta > 223 K a nano- or microcrystalline material is formed, whereas for Ta < 223 K phase aII is homogeneous and disordered. Our data strongly suggest that some of the TPP molecules in phase aII tend toward a parallel alignment. The regions, where the molecules preferentially align appear to be spatially separated and consist of only a few molecules. Whereas the mean cubic expansion of an individual region does not change within the experimental error, the percentage of correlated molecules increases with rising Ta. Based on our results, phase aII can consistently be described as a second liquid, where a part of the molecules exhibit structural correlations. The transformation of the supercooled liquid into phase aII is therefore considered as a liquid−liquid phase transition.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | PMID: 15631484 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie III > Lehrstuhl Anorganische Chemie III - Univ.-Prof. Dr. Jürgen Senker Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie III |
| Titel an der UBT entstanden: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Eingestellt am: | 21 Nov 2017 10:06 |
| Letzte Änderung: | 21 Nov 2017 10:06 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/40534 |