PREPARATION B-11, C-13, H-1-NMR SPECTRA A ND VIBRATIONAL-SPECTRA OF 1,2-XYLYLENE-PENTAHYDRO-CLOSO-HEXABORATE, CIS-[B6H5(CH2)(2)C6H4](-), AND THE CRYSTAL-STRUCTURES OF CIS-[P(C6H5)(4)][B6H5(CH2)(2)C6H4] AND CIS-[(N-C4H9)(4)N][B6H5(CH2)(2)C6H4]

By reaction of [B6H6](2-) with omega,omega'-dibromo-o-xylene in aceton itrile the 1,2-xylylenepentahydro-closo-hexaborat, cis-[B6H5(CH2)(2)C6 H4](-), is formed. The new ansa compound has been separated from exces s [B6H6](2-) and other reaction products by ion exchange chromatograph y on diethylaminoethyl cellulose. The crystal structures of cis-[P(C6H 5)(4)][B6H5(CH2)(2)C6H4] (I) and cis-[(n-C4H9)(4)N][B6H5(CH2)(2)C6H4] (II) have been determined by single crystal X-ray diffraction analysis : I is monoclinic, space group P2(1)/n with a = 13.715(5), b = 11.118( 1) and c = 19.702(2) Angstrom, beta = 103.47(2)degrees; II is orthorho mbic with a = 10.204(7), b = 13.352(4) and c = 20.824(8) Angstrom. The B-11 NMR spectrum confirms the structure with a hetero disubstituted octahedral B-6 cage with local C-2v symmetry. The C-13 and H-1 NMR spe ctra have been assigned in term of such a configuration. The IR and Ra man spectra exhibit characteristic CH, BH, BC, B-6 and arene vibration s.