Monoorganobismuth(iii) dihalides containing the new pincer 2,6-{MeN(CH2CH2)2NCH2}2C6H3ligand: solution NMR, vibrational and single-crystal X-ray studies

Abstract

The reaction of RLi [R = 2,6-{MeN(CH₂CH₂)₂NCH₂}₂C₆H₃] with BiCl₃ (1:1 molar ratio) afforded RBiCl₂ (2). RBiBr₂ (3) and RBiI₂ (4) were obtained by halogen-exchange reactions from 2. The organobismuth(III) dihalides containing the new steric demanding (N,C,N)-pincer ligand were characterized both in solution and solid state. The molecular structures of compounds 2–4 were established by single-crystal X-ray diffraction. They all show a T-shaped CBiX₂ core, stabilized by two strong intramolecular N→Bi interactions in trans positions to each other. The overall (N,C,N)BiX₂ core exhibits a distorted square-pyramidal coordination geometry. The NMR studies provided evidences for the presence of internal nitrogen-bismuth coordination in solution too. DFT calculations were performed on the related species [2,6-(R₂NCH₂)₂C₆H₃]BiX₂ (R = H, Me; X = Cl, Br, I) in order to elucidate the bond nature and vibrational spectroscopic features of these compounds.