Organobismuth(III) Dihalides with T-Shaped Geometry Stabilized by Intramolecular N→Bi Interactions and Related Diorganobismuth(III) Halides

Abstract

Organobismuth(III) compounds containing (N,C,N)-pincer ligands were prepared and characterized both in solution and in the solid state. Compound RBiCl2 1 [R = 2,6-(Me2NCH2)2C6H3] was obtained from RLi and BiCl3 (1:1 molar ratio). RBiBr2 2 and RBiI2 3 were obtained by halogen-exchange reactions from 1. Reaction of 1 with MeMgI afforded RBi(Me)I 4. Compound R2BiCl 5, obtained from RLi and BiCl3, is rearranged in solution to 1 and R3Bi. The molecular structures of compounds 1−5 were established by single-crystal X-ray diffraction. All dihalides RBiX2 show a T-shaped CBiX2 core. They are the first stable compounds corresponding to the edge inversion “transition state” at the bismuth center, stabilized by two strong intramolecular N→Bi interactions in trans positions to each other, which contribute to an overall distorted square pyramidal (N,C,N)BiX2 coordination geometry. The electronic structure of [2,6-(Me2NCH2)2C6H3]BiCl2 (1) was analyzed by density functional theory (DFT) calculations, which provide evidence that the stabilization of the square pyramidal geometry of bismuth is electronic rather than steric in nature.

Neutral organoantimony(III) and organobismuth(III) ligands as acceptors in transition metal complexes – Role of substituents and co-ligands

“…10 In such cases X-ray structural characterisation demonstrates that, in the solid state, a conformation is adopted which allows close approach of the other donor atom to a Sb centre to well within the sum of the Van der Waals radii of the two atoms, indicating the presence of an interaction. These interactions can stabilise unusual species 11 and induce chirality in otherwise achiral molecules.…”

Syntheses, solid-state structures, solution behavior of hypervalent organobismuth(III) compounds [2-(Et2NCH2)C6H4] BiX3− and DFT characterization of [2-(Me2NCH2)C6H4] BiX3− [X = Cl, Br, I; n= 1–3]

“…In recent years, density functional theory (DFT) [48] has been widely acknowledged as a theoretical approach capable of providing very accurate information at acceptable computational costs, e.g. evidences for the electronic rather than steric stabilization of the square-pyramidal geometry of bismuth in [2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ]BiCl 2 were confirmed by theoretical calculations [49]. In this context, we recently reported on a hybrid DFT investigation aimed to interpret structural and spectroscopic properties of monoorganobismuth(III) dihalides containing the 2,6-[MeN(CH 2 CH 2 ) 2 NCH 2 ] 2 C 6 H 3 pincer ligand [33].…”

“…Interestingly, the stabilization energy calculated for (8) 2 is of the same order of magnitude of that found in the case of the monoorganobismuth(III) dichloride of the 2,6-(Me 2 NCH 2 ) 2 C 6 H 3 pincer ligand containing a T-shaped CBiCl 2 core on passing from one to two N ? Bi interactions [49].…”

Solid‐State Structure and Behaviour in Solution of Hypervalent Organotin(IV) Derivatives Containing 2‐(Me2NCH2)C6H4 Moieties

“…[30] as described for related organotin [7,[31][32][33][34] and other main-group-metal compounds, [35][36][37][38][39] and indeed all compounds reported here crystallize as racemates.…”