Darstellung und spektroskopische Charakterisierung von Methylnitro-closo-hexaboraten sowie Kristallstrukturen von cis-(Ph₄As)₂[B₆H₄(CH₃)(NO₂)],fac-(Ph₄As)₂[B₆H₃(CH₃)(NO₂)₂] · CH₃CN und mer-(Ph₄P)₂[B₆H₃(CH₃)(NO₂)C₂] / Synthesis and Spectroscopic Characterization of Methylnitro-closo-hexaborates and Crystal Structures of cis -(Ph₄As)₂[B₆H₄(CH₃)(NO₂)],fac-(Ph₄As)₂[B₆H₃(CH₃)(NO₂)₂] · CH₃CN and mer-(Ph₄P)₂[B₆H₃(CH₃)(NO₂)C₂]

Abstract

By electrochemical oxidation of (n-Bu 4 N)[B 6 H 6 (CH 3 )] in the presence of nitrite ions and of the base DBU in dichloromethane solution cis- and trans-[B 6 H 4 (CH 3 )(NO 2 )] 2- , fac- [B 6 H 3 (CH 3 )(NO 2 ) 2 ] 2- and mer-[B 6 H 3 (CH 3 )(NO 2 ) c 2 ] 2- are formed. X-ray diffraction analyses have been performed on single crystals of cis-(Ph 4 As) 2 [B 6 H 4 (CH 3 O)(NO 2 )] (1) (monoclinic, space group P2 1 /a, a = 20.063(2), b = 10.858(1), c =21.384(2) Å, β = 105.818(9)°, Z = 4), fac-(Ph 4 As) 2 [B 6 H 3 (CH 3 )(NO 2 ) 2 ] ·CH 3 CN (2) (triclinic, space group P1̄, a = 10.333(3), b = 10.695(3), c = 22.833(6) Å, α = 93.91(3), β = 96.79(3), γ = 104.56(2)°, Z = 2), and mer-(Ph 4 P) 2 [B 6 H 3 (CH 3 )(NO 2 ) c 2 ] (3) (triclinic, space group P1̄, a - 10.100(1), b = 10.402(3), c = 22.923(3) Å, α = 96.328(18), β = 89.928(12), γ = 107.963(16)°, Z = 2). The 11 B NMR spectra and the vibrational spectra of the methylnitro compounds are discussed and compared with those of the monomethyl- and mononitro-closo-hexaborates.