Activation and Catalytic Degradation of SF6 and PhSF5 at a Bismuth Center

Routes to Pt Derivatives of High-Valent Sulfur Oxofluorides S(═O)2F, S(═O)F2, and S(═O)F3 by Fluorination and Oxygenation

Metal derivatives of high-valent sulfur fluorides and oxofluorides can provid e fluorinated building blocks for materials science and bioactive compounds, but so far, such building blocks are elusive. The paper describes routes to access remarkable metal derivatives of S(═O)2F, S(═O)F2, and S(═O)F3 by oxygenation or fluorination steps. The Pt(II) fluorido complex trans-[Pt(F)(SOF)(PCy3)2] (2) reacts with the Davis reagent (3-phenyl-2-(phenylsulfonyl)-1,2-oxaziridine) to yield the sulfuryl fluorido complex trans-[Pt(F)(SO2F)(PCy3)2] (4). Notably, the electrophilic fluorinating agent NFSI (N-fluorobenzenesulfonimide) reacts with 2 to form trans-[Pt(F)(SOF2)(PCy3)2][NFSO2Ph] (5a). By nucleophilic fluorination with TMAF (Me4NF) it is possible to fluorinate the sulfur center once more to give the complex trans-[Pt(F)(SOF3)(PCy3)2] (6) bearing an unprecedented SOF3 ligand. Above 283 K, complex 6 shows a decomposition of the SOF3 moiety to form trans-[Pt(F)2(PCy3)2] (7) and SOF2. The described complexes could represent a previously unknown class of transfer reagents for high-valent sulfur fluoride units.

Electron donor-acceptor (EDA) complex mediated visible-light driven sulfur-fluorine bond reduction of pentafluorosulfanyl arenes using potassium iodide

The reduction of sulfur-fluorine (S-F) bonds in pentafluorosulfanyl arenes, which is mediated by an electron donor-acceptor (EDA) complex, is described. Treatment of pentafluorosulfanyl arenes with allyltributylstannane and potassium iodide under photoirradiation conditions furnished allyl sulfides in up to 81% yield. The S-F bond reduction in pentafluorosulfanyl arenes was realized using only potassium iodide and visible light irradiation.

Aryl Silicon Nucleophiles in Bismuth Catalysis

We present a catalytic protocol utilizing bismuth for the synthesis of aromatic fluorinated thiosulfones, showcasing a seminal example of aryl silicon nucleophiles in Bi catalysis. This catalytic process is enabled by a series of Bi-based organometallic transformations, including an unprecedented transmetalation of aryl silicates to Bi(III) complexes and the formal migratory insertion of sulfur dioxide (SO2) into the Bi-C bond. The protocol is compatible with a wide range of anionic and neutral Ar-Si compounds, including heterocycles. Stoichiometric investigations of individual organometallic steps provide strong evidence supporting a Bi-redox-neutral catalytic cycle.

Construction of Multiple Nonpolar SF6 Nano-Traps by Highly Stable Pyrazole-Based MOFs for SF6 Recovery

Sulfur hexafluoride (SF6), widely used in electric power systems, is one of the most potent greenhouse gases. Efficient separation of SF6/N2 by adsorptive separation technology based on porous materials is of great significance in the industry yet remains a daunting challenge. Herein, a novel strategy is introduced to construct unique pore channels with multiple SF6 nano-traps by precisely selecting bipyrazole ligands to design the nonpolar surface of microporous metal-organic frameworks (MOFs), which significantly enhances the material's affinity for SF6. A series of ultra-stable bipyrazole-based MOFs, M(BPZ) (M═Co, Ni, Zn), are synthesized and investigated. Among these three materials, Co(BPZ) and Zn(BPZ) show excellent SF6 uptakes of 2.47 and 2.39 mmol g-1 at 298 K and 0.1 bar while Co(BPZ) exhibits the highest SF6/N2 (10/90, v/v) IAST selectivity of 748. Breakthrough experiments reveal that SF6/N2 mixtures can be efficiently separated by Co(BPZ) with a high SF6 (≥99.5 %) productivity of 46.1 L kg-1. Theoretical calculations suggest that SF6 preferably adsorbs in the channels through multiple S-F···π (pyrazole rings) van der Waals interactions. This work provides a straightforward approach for exploring adsorbents in efficient SF6/N2 separation.

Activation and C-C Coupling of Aryl Iodides via Bismuth Photocatalysis

Within the emerging field of bismuth redox catalysis, the catalytic formation of C-C bonds using aryl halides would be highly desirable; yet such a process remains a synthetic challenge. Herein, we present a chemoselective bismuth-photocatalyzed activation and subsequent coupling of (hetero)aryl iodides with pyrrole derivatives to access C(sp2)-C(sp2) linkages through C-H functionalization. This unique reactivity is the result of the bismuth complex featuring two redox state-dependent interactions with light, which 1) activates the Bi(I) complex for oxidative addition via MLCT, and 2) promotes the homolytic cleavage of aryl Bi(III) intermediates through a LLCT process.