Poly-pnictogen bonding: trapping halide ions by a tetradentate antimony(iii) Lewis acid

Abstract

A tetradentate host system with four CC–Sb(C2F5)2 functions binds halide ions in a distorted square planar coordination. Experimental and calculated structures reveal a complex interplay of attractive pnictogen bonding and Coulomb repulsion.

Oxidation-dependent Lewis acidity in chalcogen adducts of Sb/P frustrated Lewis pairs

“…The C(1)–Sb(1)–O(1) angle of 153.9(1)/150.4(1)°, which should be closer to 180° for a σ-hole interaction, also supports this. In other molecules, such as (F 5 C 2 ) 2 SbCH 2 P( t Bu) 2 ·CS 2 , the CS 2 adduct of 1 , 25 or anthracene-based poly Lewis acids with terminal Sb(C 2 F 5 ) 2 functions, 16 we have presented examples of this σ-hole interaction between a Lewis acidic antimony( iii ) function and Lewis bases.…”

“…14,15 Our group has recently presented rigid systems, based on anthracene, substituted with strong Lewis acidic Sb(C 2 F 5 ) 2 functions, which allow the chelate-binding of halide ions and various Lewis bases in the form of pnictogen bonds. 16 In antimony-containing systems the Lewis acidity can be varied both by oxidation of the antimony atom from III to V and by the electron withdrawing substituents. The apparent influence of the oxidation state on the Lewis acidity of organoantimony compounds has been investigated in terms of the distinctness of the σ-holes.…”

Bidentate boron Lewis acids: synthesis by tin boron exchange reaction and host–guest complex formation

“…[21][22][23] PLAs combine multiple Lewis acid functions via a mostly organic backbone. Although a wide variety of elements are used in PLAs, such as silicon, 24 tin, 25,26 antimony 11,27,28 or mercury, 29 a high percentage of PLAs contain group 13 elementsparticularly boron 12,21,[30][31][32][33] due to their natural electron deficiency.…”

Polydentate chalcogen bonding: anion trapping with a water-stable host compound carrying Se–CF3 functions

“…It is evident, that the design of the host system is of major importance for the activity of the respective compound. Recently, we have established diethinylanthracene 29 and its syn -photodimer 1 as potent organic backbones for bi- and tetradentate pnictogen bonding by attaching CC–Sb(C 2 F 5 ) 2 functions. They can cooperatively bind various nucleophiles such as chalcogenides or halide ions, and the tetradentate host F has been shown to clearly outperform the bidentate system E .…”

“…Poly σ-hole host compounds with the ability to cooperatively bind nucleophiles can be more active than their monodentate derivatives because they benefit from a comparable effect to the chelate effect which is well known for polydentate donor ligands. [1][2][3][4][5][6] Preorganization of the host compound can further enhance the binding abilities. 7,8 Consequently, such compounds are of great interest for processes such as catalysis, [8][9][10] anion recognition in host-guest chemistry [11][12][13] or anion transport.…”