14/15N-NMR und 11B-NMR-Daten von Trifluormethylthioaminoboranen mit natürlicher Isotopenhäufigkeit

^14/15N N.M.R. and ¹¹B N.M.R. Data of Trifluoromethylthioamino-boranes with Natural Isotope Abundance (Part 2) ^14/15N as well as ¹¹B-NMR data for trifluoromethylthioabminoboranes of the types XnBN(SCF₃)₂], with X = F, Cl, Br, N₃, or NHSCF₃, n = 0, 1 or 2, and Cl_3?nB(NHSCF₃)n with n = 1, 2 or 3, as well as for the amine-borne Me₃NBCl₂N(SCF₃)₂ and the cyclic borazene (CF₃SNHBNH)₃ are reported. These data are used, together with a qualitative analysis of the bonding situation based on observed rotational barriers and known structures, to analyse for B ← N back donation in these compounds. Relatively small variations in δ^14/15N compared to those observed for alkylaminoboranes as well as large variations in δ¹¹B are suggestive of small contributions only from back bonding. In addition the ?halogene like”? nature of the (CF₃S)₂N group is confirmed. For the series X₂BN(SCF₃)₂ (X = F, Cl, Br on N₃), XBN(SCF₃)₂]₂ (X = Cl, Br, N₃ or N(SCF₃)₂) and Cl_n?3B(NHSCF₃)_n (n = 1, 2 or 3) a linear relationship for δ¹¹B and δ^14/15N is observed. It is furtheron demonstrated that hitherto known δ^14/15N/¹¹B correlations are valid only in case of strong B ← N back donation.