BORONIC ACIDS AS MOLECULAR SENSORS - NBO ANALYSIS AND C-13 CHEMICAL-SHIFTS AS TOOLS FOR EVALUATION OF DFT GEOMETRY OPTIMIZATION OF COMPLEXES OF DIPHENYLMETHANE 3,3'-DIBORONIC ACIDS AND GLUCOSE

Studies on the formation of bisdentate complexes of diphenylmethane-3, 3'-diboronic acid 1 and glucose were carried out using DFT methods. A 1,2- and 5,6-coordinated complex (i.e. 2) was chosen (on the basis of a recent NMR spectroscopic study) as a most probable model of plausibl e isomeric structures which 1 could form as reacting with hydroxylic p ositions (total of 5) of glucose (in the furanose form). The optimized structure of 2 was found to be closely similar to that proposed on th e basis of the earlier NMR study, The calculated C-13 NMR shifts were closely similar to the measured ones. A more glucose selective analog of the sensor 1 was proposed. Copyright (C) 1996 Elsevier Science Ltd