11B NMR study of p-carboxybenzeneboronic acid ions for complex formation with some monosaccharides.
The 11B NMR spectra of p-carboxybenzeneboronic acid (PCBA) ions demonstrated that their chemical shifts depend on the pH. At a lower pH, PCBA exists as a mixture of neutral PCBA and the monoanion with a trigonal structure, and at higher pH as the dianion with a tetrahedral structure. In the intermediate pH region, both the mono- and dianion coexist. The pKa of the monoanion of PCBA has been estimated to be 8.53. The complex formation constants of PCBA with several monosaccharides suggest that PCBA-fructose complex is most predominant.
Islam
T M Bulbul
TM
Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621, Japan.
Yoshino
Kazuo
K
Sasane
Akinobu
A
D016754:Boron Neutron Capture Therapy; D001897:Boronic Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009005:Monosaccharides / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry
D001897:Boronic Acids; D007477:Ions; D009005:Monosaccharides; D012996:Solutions