Antimony(III) and bismuth(III) amides containing pendant N-donor groups--a combined experimental and theoretical study

Squeezing Bi: PNP and P2N3 pincer complexes of bismuth

We report the first application of a rigid P2N3 pincer ligand in p-block chemistry by preparing its bismuth complex. We also report the first example of bismuth complexes featuring a flexible PNP pincer ligand, which shows phase-dependent structural dynamics. Highly electrophilic, albeit thermally unstable, Bi(iii) complexes of the PNP ligand were also prepared.

Catalytic Activation of N2O at a Low-Valent Bismuth Redox Platform

Herein we present the catalytic activation of N₂O at a Bi^I⇄Bi^III redox platform. The activation of such a kinetically inert molecule was achieved by the use of bismuthinidene catalysts, aided by HBpin as reducing agent. The protocol features remarkably mild conditions (25 °C, 1 bar N₂O), together with high turnover numbers (TON, up to 6700) and turnover frequencies (TOF). Analysis of the elementary steps enabled structural characterization of catalytically relevant intermediates after O-insertion, namely a rare arylbismuth oxo dimer and a unique monomeric arylbismuth hydroxide. This protocol represents a distinctive example of a main-group redox cycling for the catalytic activation of N₂O.

Syntheses and Molecular Structures of Heteroleptic and Homoleptic Antimony(III) Tetrafluorophenylethylenediamidate Complexes

A series of hetero- and homoleptic organoamidoantimony(iii) complexes of the type [SbLMe3−nCln] (n=2, 1, 0) (HLMe=p-HC6F4NH(CH2)2NMe2) incorporating a bulky amido fluorinated ligand tethered with an amino pendant arm, have been successfully synthesised and fully characterised as monomers in the solid state. [Sb(p-HC6F4NC2H4NMe2)Cl2] (1), [Sb(p-HC6F4NC2H4NMe2)2Cl] (2), and [Sb(p-HC6F4NC2H4NMe2)3] (3) were isolated by metathesis reactions involving different stoichiometric ratios between SbCl3 and Li(p-HC6F4N(CH2)2NMe2) (LiLMe) in non-coordinating solvents, while [Sb(p-HC6F4NC2H4NMe2)Cl2] (1) was also synthesised by the direct reaction between SbCl3 and HLMe in THF providing an interesting alternative pathway to access these types of compounds.

Synthesis and Crystal Structures of the First Antimony(III) Aziridinides

The first antimony(III) aziridinyl derivatives are reported. Treatment of anhydrous SbCl₃ with N-lithioaziridine Li(Azn) (Azn = NC₂H₄) afforded the structurally unique heterobimetallic lithium/antimony(III) amide complex [Li₃Sb(μ₃-Cl)₂(μ-Azn)₄(THF)₂]_∞ (1). Homoleptic Sb₂(Azn)₆ (2) has become available for the first time through an amide group exchange reaction between Sb(NMe₂)₃ and 3 equiv of aziridine. The low-melting Sb₂(Azn)₆ exhibits a "weak dimer" structure in the crystal.

Hydrosilylation in Aryliminopyrrolide-Substituted Silanes

A range of silanes was synthesized by the reaction of HSiCl3 with iminopyrrole derivatives in the presence of NEt3 . In certain cases, intramolecular hydrosilylation converts the imine ligand into an amino substituent. This reaction is inhibited by factors such as electron-donating substitution on Si and steric bulk. The monosubstituted ((Dipp) IMP)SiHMeCl ((Dipp) IMP=2-[N-(2,6-diisopropylphenyl)iminomethyl]pyrrolide), is stable towards hydrosilylation, but slow hydrosilylation is observed for ((Dipp) IMP)SiHCl2 . Reaction of two equivalents of (Dipp) IMPH with HSiCl3 results in the hydrosilylation product ((Dipp) AMP)((Dipp) IMP)SiCl ((Dipp) AMP=2-[N-(2,6-diisopropylphenyl)aminomethylene]pyrrolide), but the trisubsitituted ((Dipp) IMP)3 SiH is stable. Monitoring the hydrosilylation reaction of ((Dipp) IMP)SiHCl2 reveals a reactive pathway involving ligand redistribution reactions to form the disubstituted ((Dipp) AMP)((Dipp) IMP)SiCl as an intermediate. The reaction is strongly accelerated in the presence of chloride anions.