Darstellung, ¹¹B-, ¹³C-, ¹H-NMR- und Schwingungsspektren von 1.2-Trimethylenpentahydro-closo-Hexaborat(1 - ) , cis - [B₆H₅(CH₂)₃]^- und 1.2-Tetramethylenpentahydro-closo-Hexaborat(1-), cis-[B₆H₅(CH₂)₄]^- sowie Kristallstrukturen von [P(C₆H₅)₄][B₆H₅(CH₂)₃] und [P(C₆H₅)₄][B₆H₅(CH₂)₄] / Preparation, ¹¹B, ¹³C, ¹H NMR and Vibrational Spectra of 1.2-Trim ethylenepentahydro-closo-hexaborate(1-), cis-[B₆H₅(CH₂)₃]^-, and 1.2-Tetramethylenepentahydro-closo-hexaborate(1-), cis-[B₆H₅(CH₂)₄]^-, and the Crystal Structures of [P(C₆H₅)₄][B₆H₅(CH₂)₃] and [P(C₆H₅)₄][B₆H₅(CH₂)₄]

Abstract

By reaction of [B 6 H 6 ] 2- with diiodopropane or diiodobutane in dichloromethane the 1,2- rimethylene-pentahydro-closo-hexaborate(1-), cis-[B 6 H 5 (CH 2 ) 3 ] - , and the 1,2-tetra-methylene- entahydro-closo-hexaborate(1-), dv-[B 6 H5(CH 2 ) 4 ] - are obtained, respectively. The compounds were separated from excess [B 6 H 6 ] 2- by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of [P(C 6 H 5 )4][B 6 H 5 (CH 2 )3] (I) and [P(C 6 H 5 )4][B 6 H 3 (CH 2 )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 P2 1 /c with a =9,7855(10), b = 11,0793(10), c = 25,2386(10) Å, β= 2,491(10)°. The 11 B NMR spectra of oth compounds reveal the feature of a cis-disubstituted octahedral B 6 cage. The 13 C NMR pectrum of I exhibits a quartet at 15,46 ppm with 1 J(C,B) = 121,7 Hz (B-CH 2 ) and a triplet at 37,98 ppm with 1 J(C,H) = 124,4 Hz (CH 2 ). For II a quartet at 12,89 ppm with 1 J(C,B) = 105,5 Hz (B-CH 2 ) and a triplet at 30,00 ppm with 1 J(C,H) = 124,4 Hz (CH 2 ) are observed. In the 1 H NMR spectrum of I two multiplets at 0,73 and 1,90 ppm of the CH 2 groups and two singlets at 2,23 and -3,71 ppm of the BH fragments are bserved; the signals of the CH 2 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.