Affiliation:
1. Institut für Anorganische Chemie der Christian-Albrechts-Universität, Olshausenstraße 40, D-24098 Kiel
Abstract
By reaction of [B6H6]2- with diiodopropane or diiodobutane in dichloromethane the 1,2- rimethylene-pentahydro-closo-hexaborate(1-), cis-[B6H5(CH2)3]-, and the 1,2-tetra-methylene- entahydro-closo-hexaborate(1-), dv-[B6H5(CH2)4]- are obtained, respectively. The compounds were separated from excess [B6H6]2- by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of [P(C6H5)4][B6H5(CH2)3] (I) and [P(C6H5)4][B6H3(CH2)4] (II) have been determined by single crystal X-ray diffraction analysis: I is triclinic, space group P1̅ with a = 7,388(2), b = 12,254(2), c = 14,415(2) Å, α = 85,638(12)°, β= 84,06(2)°, γ = 85,13(2)°; II is monoclinic, space group P21/c with a =9,7855(10), b = 11,0793(10), c = 25,2386(10) Å, β= 2,491(10)°. The 11B NMR spectra of oth compounds reveal the feature of a cis-disubstituted octahedral B6 cage. The 13C NMR pectrum of I exhibits a quartet at 15,46 ppm with 1J(C,B) = 121,7 Hz (B-CH2) and a triplet at 37,98 ppm with 1J(C,H) = 124,4 Hz (CH2). For II a quartet at 12,89 ppm with 1J(C,B) = 105,5 Hz (B-CH2) and a triplet at 30,00 ppm with 1J(C,H) = 124,4 Hz (CH2) are observed. In the 1H NMR spectrum of I two multiplets at 0,73 and 1,90 ppm of the CH2 groups and two singlets at 2,23 and -3,71 ppm of the BH fragments are bserved; the signals of the CH2 groups of II are at 0,60 and 1,35 ppm and of the BH fragments at 2,15 and -4,81pm,respectively. The IR and Raman spectra exhibit five very strong CH stretching bands between 2807 and 2938 cm-1 in case of I and between 2817 and 2889 cm 1 in case of II.