Analytical Sciences

Abstract − Analytical Sciences, 29(8), 843 (2013).

13C and 27Al NMR Study of Complexation between Aluminium Ion and Simple Dicarboxylic Acids under an Acidic Condition: New Peak Assignments of 27Al NMR Spectra of Mixed Solutions of Al3+ and Simple Dicarboxylic Acids
Mayumi ETOU,* Tsutomu KURISAKI,** Yoshihiro OKAUE,* Hisanobu WAKITA,** and Takushi YOKOYAMA*
*Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1 Hakozaki, Higashi, Fukuoka 812-8581, Japan
**Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan, Fukuoka 814-0180, Japan
Due to a consideration of Al detoxicification by simple carboxylic acid, the interaction between aluminium ion (Al3+) and three dicarboxylic acids (oxalic acid (OX), malonic acid (MA) and succinic acid (SU)) under an acidic condition was investigated using 13C and 27Al NMR techniques. Based on deconvolution of the 27Al NMR spectra and quantitative 13C NMR spectra, the structure of each complex was elucidated. Especially, we focused on the peak assignments of 27Al NMR spectra by combining of the results of quantitative 13C NMR spectra. In the OX system, the peak at 16 ppm in the 27Al NMR spectrum originates from Al(OX)33− and Al(OX)2−, and the ratio of each complex depends on the OX/Al molar ratio. In the MA system, the three complexes (Al(MA)2−, Al(MA)33− and Al(MA)+) are represented in the peak at 2 ppm in the 27Al NMR spectrum. The assignment of peaks in the 27Al NMR spectra in this study differs from those described in previous papers.