Syntheses, solid-state structures, solution behavior of hypervalent organobismuth(III) compounds [2-(Et 2NCH 2)C 6H 4] nBiX 3−n and DFT characterization of [2-(Me 2NCH 2)C 6H 4] nBiX 3−n [X = Cl, Br, I; n = 1–3

Abstract

The reaction of RLi [R = 2-(Et 2NCH 2)C 6H 4] with BiCl 3 in 3:1 or 2:1 molar ratio afforded R 3Bi ( 1) and R 2BiCl ( 2), respectively. Redistribution reactions between 1 and BiCl 3 (1:2 molar ratio) resulted in RBiCl 2 ( 5). R 2BiBr ( 3) formed from RMgBr and BiCl 3 (2:1 molar ratio). R 2BiI ( 4) and RBiX 2 [X = Br ( 6), I ( 7)] were obtained from 2 and 5 by halogen-exchange reactions using KX in water/CH 2Cl 2 mixture. Compounds 1– 7 were characterized by FT-Raman/IR, 1H and 13C NMR spectroscopies as well as mass spectrometry. The structures of 1– 4 were determined by single-crystal X-ray diffraction. They all have pyramidal C 3Bi or C 2BiX cores. For R 3Bi ( 1) intramolecular N → Bi interactions of medium strength [Bi(1)–N(1) 3.214(7) Å] result in an overall distorted octahedral ( C, N) 3Bi core. In the monohalides 2– 4 one nitrogen is strongly coordinated to bismuth trans to the halogen [range 2.571(8)–2.645(6) Å], 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) Å]. The overall ( C, N) 2BiX (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 RBiX 2 species. DFT calculations were performed on the related compounds R′BiX 2 [X = Cl ( 8), Br ( 9), and I ( 10)], R′ 2BiX [X = Cl ( 11), Br ( 12), and I ( 13)], and R′ 3Bi ( 14) [R′ = 2-(Me 2NCH 2)C 6H 4] in order to elucidate the bond nature and vibrational spectroscopic features of this class of organobismuth(III) compounds.