Syntheses, solid-state structures, solution behavior of hypervalent organobismuth(III) compounds [2-(Et2NCH2)C6H4]nBiX3-n and DFT characterization of [2-(Me2NCH2)C6H4]nBiX3-n [X = Cl, Br, I; n=1-3]

The reaction of RLi [R = 2-(Et2NCH2)C6H4] with BiCl3 in 3:1 or 2:1 molar ratio afforded R3Bi (1) and R2BiCl (2), respectively. Redistribution reactions between 1 and BiCl3 (1:2 molar ratio) resulted in RBiCl2 (5). R2BiBr (3) formed from RMgBr and BiCl3 (2:1 molar ratio). R2BiI (4) and RBiX2 [X = Br (6), I (7)] were obtained from 2 and 5 by halogen-exchange reactions using KX in water/CH2Cl2 mixture. Compounds 1-7 were characterized by FT-Raman/IR, H-1 and C-13 NMR spectroscopies as well as mass spectrometry. The structures of 1-4 were determined by single-crystal X-ray diffraction. They all have pyramidal C3Bi or C2BiX cores. For R3Bi (1) intramolecular N -> Bi interactions of medium strength [Bi(1)-N(1) 3.214(7) angstrom] result in an overall distorted octahedral (C,N)(3)Bi core. In the monohalides 2-4 one nitrogen is strongly coordinated to bismuth trans to the halogen [range 2.571(8)-2.645(6) angstrom], while the second one is involved in a considerably weaker intramolecular N -> Bi interaction trans to a carbon atom [range 2.992(12)-3.170(8) angstrom]. The overall (C,N)(2)BiX (X = Cl, Br, I) core is distorted square-pyramidal. The NMR studies provided evidence for the presence of internal nitrogen-bismuth coordination in solution for RBiX2 species. DFT calculations were performed on the related compounds R'BiX2 [X = Cl (8), Br (9), and I (10)], R'2BiX [X = Cl (11), Br (12), and I (13)], and R'Bi-3 (14) [R' = 2-(Me2NCH2)C6H4] in order to elucidate the bond nature and vibrational spectroscopic features of this class of organobismuth(III) compounds. (C) 2010 Elsevier B.V. All rights reserved.