PREPARATION, B-11, C-13, H-1-NMR AND VIBR ATIONAL-SPECTRA OF PHENYLUNDECAHYDRO-CLOSO-DODECABORATE(2-) AND CRYSTAL-STRUCTURE OF [AS(C6H5)(4)](2)[(C6H5)B12H11]

By reaction of [N(C4H9)(4)](2)[B12H12] with chlorotriphenyltin at 170 degrees C the phenylundecahydro-closo-dodecaborate anion [(C6H5)B12H11 ](2-) is formed which can be isolated by ion exchange chromatography o n diethylaminoethyl(DEAE) cellulose. The crystal structure of [As(C6H5 )(4)](2)[(C6H5)B12H11] has been determined by single crystal X-ray dif fraction analysis: triclinic, space group P (1) over bar with a = 11.0 066(11), b = 11.1371(6), c = 22.236(2) Angstrom, alpha = 93.040(6), be ta = 92.981(8), gamma = 100.254(6)degrees, Z = 2. The B-11 NMR spectru m reveals the features (1:5:5:1) of a monosubstituated B-12 cage with the ipso B atom at -6.1 and the antipodal B at -17.4 ppm. The C-13 and H-1 NMR spectra show the characteristic patterns of the phenyl group. The IR and Raman spectra exhibit characteristic BH stretching vibrati ons between 2464 and 2519 cm(-1) and the CC stretching vibrations in t he range of 1405 to 1592 cm(-1).