PREPARATION AND SPECTROSCOPIC CHARACTERIZATION OF CARBOXYLATODODECABORATES

The tetrabutylammonium salt (TBA)(2)[B12H12](2-) reacts with formic, acetic, cyanoacetic, phenylacetic, propionic, butyric, and thioacetic acid at temperatures between 80 and 150 degrees C forming the carboxylatododecaborates [(RC(O)O)(n)-B12H12-n](2-), n = 1, 2, [CH3C(O)S-B12H11](2-). The isolation of the pure compounds is achieved by ion exchange chromatography on diethylaminoethyl cellulose. In case of the dicarboxylatododecaborates beside the 1,7-isomer predominantly the 1,2-isomer, while 1,2-[(OH)C6H5CH2C(O)O-B12H10](2-) is formed exclusively. The alcaline hydrolysis of [RC(O)O-B12H11](2-) and 1,2[(OH)C6H5CH2C(O)O-B12H10](2-) results in [(OH)-B12H11](2-) and 1,2-[(OH)(2)-B12H10](2-). All compounds are characterized by their B-11-nmr, C-13-nmr and IR spectra. The B-11-nmr signals are assigned by a sheme allowing to establish expected spectra.