Synthesis, B-11, H-1 NMR and vibrational spectra of 4-aminopyridylundecahydro-closo-dodecaborate(1-) and crystal structure of (Ph4As)[(4-(NH)-C5H4N)B12H11]center dot 2CH(3)CN

By reaction of (n-Bu4N)(2)[B12H12] with 4-aminopyridine at 190 degrees C the 4-aminopyridylundecahydro-closo-dodecaborate anion [(4-(NH)-C5H4N)B12H11](-) is obtained which can be separated from excess [B12H12](2-) by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The X-ray structure determination of (Ph4As)[(4-(NH)-C5H4N)B12H11]. 2CH(3)CN (orthorhombic, space group Pbca, a = 14.294(2), b = 19.587(2), c = 27.279(5)Angstrom, Z = 8) reveals that the 4-aminopyridine substituent is bonded via the nitrogen atom of the amino group. The B-11 NMR spectrum exhibits the characteristic feature (1:5:5:1) of a monosubstituated B-12 cage with a downfield shift of ipso-B1 to -5.4 and antipodal-B12 to -18.1 ppm. The H-1 NMR spectrum reveals the pattern of a monosubstituated pyridine. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2489 and 2521 cm(-1) and the CC and CN stretching vibrations in the range of 1405 to 1636 cm(-1).