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Here we present a new method to monitor fluoride transmembrane transport into liposomes using a europium( iii ) complex. We take advantage of the long emission lifetime of this probe to measure the transport activity of a fluorescent transporter. The high sensitivity, selectivity, and versatility of the assay allowed us to study different types of fluoride transporters and unravel their mechanisms of action. 

We describe the synthesis of [ o -Ph 2 P(O)(C 6 H 4 )SbPh 3 ] + ([2] + ), an intramolecularly base-stabilized stibonium Lewis acid which was obtained by reaction of [ o -Ph 2 P(C 6 H 4 )SbPh 3 ] + with NOBF 4 . This cation reacts with fluoride anions to afford the corresponding fluorostiborane o -Ph 2 P(O)(C 6 H 4 )SbFPh 3 , the structure of which indicates a strengthening of the PO → Sb interaction. When deployed in fluoride-containing POPC unilamellar vesicles, [2] + behaves as a potent fluoride anion transporter whose activity greatly exceeds that of [Ph 4 Sb] + . 

Our interest in the chemistry of tunable chalcogen and pnictogen bond donors as Lewis acidic platforms for the complexation and transport of anions has led us to investigate examples of such compounds that can be activated by redox events. Here, we describe the synthesis of [ o -MePhS(C 6 H 4 )SbPh 3 ] 2+ ([ 3 ] 2+ ) and [ o -MePhS(C 6 H 4 )Sb( p -Tol) 3 ] 2+ ([ 4 ] 2+ ), two dicationic stibonium/sulfonium bifunctional Lewis acids which were obtained by methylation of the phenylthioether derivatives [ o -PhS(C 6 H 4 )SbPh 3 ] + ([ 1 ] + ) and [ o -PhS(C 6 H 4 )Sb( p -Tol) 3 ] + ([ 2 ] + ), respectively. An evaluation of the chloride anion transport properties of these derivatives using chloride-loaded POPC unilamellar vesicles shows that the activity of the monocations [ 1 ] + and [ 2 ] + greatly exceeds that of the dications [ 3 ] 2+ and [ 4 ] 2+ , a phenomenon that we assign to the higher lipophilicity of the monocationic compounds. Harnessing this large transport activity differential, we show that [ 4 ] 2+ can be used as a prechloridophore that is readily activated by reduction of the sulfonium moiety. Indeed, [ 4 ] 2+ reacts with GSH to afford [ 2 ] + as an active transporter. This activation, which has been monitored in aqueous solution, can also be carried out in situ , in the presence of the chloride-loaded POPC unilamellar vesicles. 

Abstract With the discovery of late transition metal platforms that support clean photoreductive halogen eliminations, we now describe an indazol‐3‐ylidene gold trichloride complex ([7]⁺) decorated at the 4‐position by a xanthylium unit. This orange complex features a low energy band in the visible part of the spectrum, assigned to the charge transfer excitation of the indazol‐3‐ylidene/xanthylium donor/acceptor dyad. Green‐light irradiation of this complex in the presence of a chlorine trap elicits the clean photoelimination of chlorine radicals, producing the corresponding gold(I) complex. This visible‐light‐induced photoreduction is very efficient, reaching quantum yields close to 10 %. A neutral analog of [7]⁺featuring an anthryl group rather than a xanthylium unit proved to be perfectly photostable, supporting the importance of the xanthylium‐based photoredox unit present in [7]⁺. 

Abstract With the view of developing selective transmembrane anion transporters, a series of phosphonium boranes of general formula [p‐RPh₂P(C₆H₄)BMes₂]⁺have been synthesized and evaluated. The results demonstrate that variation of the R group appended to the phosphorus atom informs the lipophilicity of these compounds, their Lewis acidity, as well as their transport activity. Anion transport experiments in POPC‐based large unilamellar vesicles show that these main‐group cations are highly selective for the fluoride anion, which is transported more than 20 times faster than the chloride anion. Finally, this work shows that the anion transport properties of these compounds are extremely sensitive to the steric crowding about the boron atom, pointing to the crucial involvement of the Group 13 element as the anion binding site.