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NMR Chemical Shift and Quadrupolar Interaction Parameters of Carbon‐Coordinated 27 Al in Aluminium Carbide, Al 4 C 3
Author(s) -
Bräuniger Thomas,
Chandran C. Vinod,
Wedig Ulrich,
Jansen Martin
Publication year - 2011
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201000445
Subject(s) - aluminium , nmr spectra database , crystallography , chemical shift , carbide , chemistry , spectral line , analytical chemistry (journal) , carbon fibers , materials science , physics , organic chemistry , astronomy , composite number , chromatography , composite material
Aluminium carbide, Al 4 C 3 , was characterised by 13 C and 27 Al solid‐state NMR spectroscopy. The 13 C NMR spectra display two resonances with an intensity ratio of 1:2, which is in agreement with the reported crystal structure. The 27 Al NMR spectra of Al 4 C 3 under both static and MAS conditions were deconvoluted into two spectral components, belonging to the two aluminium species Al1 and Al2 in the crystal structure of Al 4 C 3 . The spectral fit allowed for determination of the relatively large quadrupolar coupling constants ( χ ≈ 16 MHz) of both 27 Al species. One aluminium species displayed a tendency of having a χ of slightly smaller magnitude compared to the other. By carrying out DFT calculations of the EFG tensor at the 27 Al sites using the Wien2k software, we could tentatively assign the smaller χ site to be the crystallographic Al1 species. Also, the isotropic chemical shift for the carbon‐coordinated aluminium in Al 4 C 3 could be determined, being in the range of 111 to 120 ppm. This is somewhat larger than those shift values observed for 27 Al in nitrogen coordination.