Developments in the chemistry of stibine and bismuthine complexes

Greenacre, Victoria K.; Levason, William; Reid, Gillian

doi:10.1016/j.ccr.2020.213698

Cited by 26 publications

(11 citation statements)

References 172 publications

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“…While often considered as mimicking the properties of phosphine and arsine ligands, recent investigations have shown that stibine ligands possess a number of distinguishing qualities that differentiate them from their lighter analogues . Indeed, owing to the larger size of antimony and its higher Lewis acidity, the antimony atom of metal-coordinated stibines has been shown to engage electron-rich entities, in particular anions as illustrated in Chart , which shows that donor coordination to the antimony atom can occur trans from the metal center ( A ) or trans to one of the antimony-bound substituents ( B ) .…”

Section: Introductionmentioning

confidence: 99%

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

2021

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As part of our interest in the chemistry of late transition metal complexes bearing cationic antimony ligands, we have investigated the reaction of ((o-(Ph 2 P)C 6 H 4 ) 3 )SbClPtCl (1) with H 2 O 2 and found that it affords [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)C 6 H 4 )SbPtCl] + ([2−Cl] + ), a monocationic complex with the newly installed P=O moiety coordinated intramolecularly to the antimony atom via a P=O → Sb dative bond. The Pt−Cl bond of this complex is readily activated by addition of a ligand such as cyclohexyl isocyanide. When carried out in the presence of AgBF 4 , this reaction affords the dicationic complex [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)-C 6 H 4 )SbPt(CNCy)] + ([2−CNCy] 2+). In addition to structurally characterizing [2−Cl] + and [2−CNCy] 2+ as their chloride and tetrafluoroborate salts, respectively, we have also studied the reaction of [2−Cl] + with AgBF 4 in the presence of PhCCH as a substrate surrogate. When monitored by 31 P NMR spectroscopy in CDCl 3 , this reaction shows the formation of a new species tentatively assigned to [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)C 6 H 4 )SbPt] 2+ ([2] 2+ ) stabilized by coordination of the alkyne. This formulation is supported by the elevated carbophilic reactivity of [2] 2+ , which readily catalyzes the cyclization of 2-allyl-2-(2propynyl)malonate. Altogether, these results show that the accumulation of charge in such reactive complexes can be facilitated by the intramolecular base-stabilization of the dinuclear core.

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Section: Introductionmentioning

confidence: 99%

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

2021

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“…Gratifyingly, both catalysts 3 and 4 provide good to excellent yields of the corresponding aziridines as evaluated by 1 H NMR spectra of the purified products (with respect to an internal standard). Both 3 (87%) and 4 (62%) can be recovered at the end of the reaction, albeit to a much lower extent for 4 , potentially reflecting the fragility of the Bi–C bond …”

Section: Resultsmentioning

confidence: 99%

“…Both 3 (87%) and 4 (62%) can be recovered at the end of the reaction, albeit to a much lower extent for 4, potentially reflecting the fragility of the Bi−C bond. 45 To evaluate the effect of partial removal of chlorides as suggested by the synthesis of compound 11 (see above), KPF 6 (3 equiv) was added to the catalytic mixture containing [(TMG 3 trphen-Sb)Cu 3 (μ-Cl) 3 ] (3). Yields of aziridines (Table 2) are not unlike those obtained in the absence of KPF 6 , save for the most electron-withdrawing styrenes (CF 3 , NO 2 ), for which unusually high yields are observed.…”

Section: ■ Introductionmentioning

confidence: 99%

Nitrene-Transfer Chemistry to C–H and C═C Bonds Mediated by Triangular Coinage Metal Platforms Supported by Triply Bridging Pnictogen Elements Sb(III) and Bi(III)

Sharma,

Fritz,

Adebanjo

et al. 2024

Organometallics

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Tripodal ligands (TMG 3 trphen-E) that feature heavy pnictogen elements (E = Sb(III), Bi(III)) and tetramethylguanidinyl (TMG) arms have been explored in stabilizing Cu(I) and Ag(I) sites and facilitating nitrene-transfer chemistry. Compounds [(TMG 3 trphen-E)M 3 (μ-X) 3 ] (M = Cu(I), Ag(I); X = Cl, Br, I) have been generated upon extraction of M 3 (μ-X) 3 units from MX sources, exhibiting support of the crown-shaped M 3 (μ-X) 3 fragment by M−N TMG bonds and triply bridging E → M 3 interactions. Orbital interactions between Cu(I) sites and N TMG residues are more dominant than Sb/Bi → Cu 3 donor interactions between the Sb 5s or Bi 6s orbitals and admixed Cu 4s/3d orbitals, with larger interaction energies computed for Sb → Cu 3 . Nonhalogenated copper compounds [(TMG 3 trphen-E) 2 Cu 2 ] 2+ 2Y − (Y = PF 6 , B(C 6 F 5 ) 4 ) have been synthesized via dechlorination by TlPF 6 or by application of halide-free Cu(I) sources with TMG 3 trphen-E ligands. Nitrene-transfer to olefins mediated by [(TMG 3 trphen-E)Cu 3 (μ-Cl) 3 ] (E = Sb and Bi) affords aziridines in good yields, primarily for unencumbered styrenes and with the more robust Sb catalyst. Amination of C−H bonds is most effective with sec-benzylic substrates and requires a more electrophilic nitrene (NTces) to achieve practicable yields with halogenated or nonhalogenated copper precursors. Hammett plots indicate that the competitive amination of para-substituted ethylbenzenes enabled by [(TMG 3 trphen-Sb)Cu 3 (μ-Cl) 3 ] involves stepwise C−H functionalization.

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“…In particular, studies on pincer ligands featuring elements of the 6th period are scarce and their chemistry remains largely unexplored. [6][7][8][9][10][11][12][13] In this context, Bi stands out as a particularly fascinating element because of its high natural abundance, low toxicity, multiple accessible oxidation states, and metallic character. These attributes have been effectively leveraged in catalytic applications in recent years.…”

Section: Introductionmentioning

confidence: 99%