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C NMR relaxation studies of 1:2 LiCl-ethylaluminum dichloride solutions |
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| Authors: | Charles E Keller Bernard J Piersma Gilbert J Mains W Robert Carper |
| Institution: | a Department of Chemistry, Wichita State University, Wichita, KS 67260-0051, USA b Department of Chemistry, Houghton College, Houghton, NY 14744, USA c Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA |
| Abstract: | A new room-temperature molten salt, 1:2 LiCl-ethylaluminum dichloride (LiCl-EtAlCl2, f.p. about 178 K), is examined using 13C relaxation methods at 7.05 T (−25 to + 80 °C). The methylene carbon undergoes scalar relaxation of the ‘second kind’ as it is coupled to a faster relaxing (quadrupolar) nucleus. LiCl-EtAlCl2 undergoes a significant liquid-state phase change between 5 and 15 °C as evidenced by observed changes in the relaxation properties of the methylene and methyl carbons and J(13C−27Al). The J(13C−27Al) coupling constants are 75 (− 10 to + 5 °C) and 11 Hz (15–65 °C), indicating a change in structure between 5 and 15 °C. Chemical shift anisotropies of 56 and 48 ppm are obtained for the methylene and methyl carbons in the EtAlCl2 dimer part of the 1:2 LiCl-EtAlCl2 solution. |
| Keywords: | 13C NMR relaxation studies Alkyl chloride complexes Aluminum complexes Coupling constants Chemical shift anisotropies |
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