To explore the origin of the robust boron chelation observed in boron(III)-C3P 1 under acidic conditions, we examined its solution behavior in the presence of trifluoroacetic acid (TFA). The proton nuclear magnetic resonance (1H NMR) spectrum of 1 recorded in dehydrated CDCl3 (at 6.0 mM) revealed only two singlet signals at 5.95 and 1.69 parts per million (ppm), which were assignable to pyrrole β-CH and methyl protons, respectively. The 11B NMR signal of 1 at 22.81 ppm indicated a trigonal-planar boron(III) center, as confirmed by its single crystal X-ray structure. When 3 equivalents of TFA were added to a solution of 1 at 25 °C, a new set of proton signals attributable to the TFA-adduct 2 appeared in a molar ratio of 1:2 = 1/2. Adduct 2 was formed through an equilibrium process; whereas the signal ratio of 2 decreased with increasing temperature (51% and 40% at 40 and 50 °C, respectively), 2 was predominant (>90%) at 0 °C (Supplementary Fig. 2). Adduct 2 showed geminally coupled methylene proton signals at 3.94 and 3.68 ppm along with six different methyl protons and five pyrrole β-CH signals, reflecting its C1 molecular symmetry. The 11B NMR signal of 2 was observed at...

Boron-dipyrromethenes (BODIPYs) are fluorophores applicable for imaging and sensing, though are sensitive to acidic deboronation. Here the authors design macrocyclic BODIPYs resistant to acid, and hav...

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Under extreme pressure and temperature, superionic water acts as a strong superacid, catalyzing methane polycondensation through pentacoordinated carbonium ions (CH5+). This discovery reveals the non...

The simplistic methylbismuth dication has been captured only by the aid of monodentate tetrahydrofuran (thf) ligands, [BiMe(thf)5]2+. The hexacoordinate species shows a very unusual pentagonal pyrami...

🧪 Article Highlight: B(C₆F₄Br)₃, prepared via silver-to-boron transmetalation, represents a new soft Lewis superacid with potential applications in catalysis and materials chemistry

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