Bor-Stickstoff-Verbindungen,LXVIII [1]. Kernresonanzspektroskopische Untersuchungen an 1,3,2-Diazaboracycloalkanen und Phenylboranderivaten

Boron-Nitrogen Compounds. LXVIII. Nuclear Magnetic Resonance Studies on 1,3,2-Diazaboracyloalkanes and Phenylborane Derivatives The ¹H chemical shift differences Δδ = δ (NCH ₂) – δ (NCH ₃) of 1,3-dimethyl1,3,2-diazaboracycloalkanes as well as the corresponding differences of ¹³C chemical shifts are dependent upon the ring size. No simple correlation exists between δ_11B and δ_13C of the boron-bonded phenyl carbon atom of phenylborane derivates, although stereochemical factors appear to influence the absolute values of δ_13C. ¹³C Nuclear resonance measurements permit the observation of conformational isomers of bis(methylamino)phenylborane and N-trimethyl-B-triphenylborazine at low temperatures and confirm the pseudoarmatic nature of the 1,3,2-diazaboroline ring system.