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Updated: Apr 25, 2026

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Iminophosphonamido-Supported Plumbyliumylidenes: Structural Effects of Counter Anions and Lewis Acid Catalysis
Yugo Kazama1, Kazuki Nakaya1, Kei Ota1
1Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
Abstract:
Two-coordinate plumbyliumylidene ions constitute a rare class of highly electron-deficient cationic Pb(II) species. Herein, we report the synthesis and structural characterization of iminophosphonamido-supported plumbyliumylidene ions bearing two different borate counteranions, {B[(4-tBuMe2Si)C6F4]4}- and [B(C6F5)4]-. Single-crystal X-ray analyses reveal pronounced ion-pairing effects that depend on the counteranion, including secondary Pb···F interactions and solvent coordination, highlighting the high Lewis acidity of the lead center. The [B(C6F5)4]- salt exhibits versatile Lewis acid catalysis, enabling living ring-opening polymerization of ε-caprolactone and L-lactide to afford well-defined polymers and PCL-block-PLA copolymers. In addition, the same cationic Pb(II) species catalyzes the hydroamination of alkynes with distinct chemoselectivity, suppressing double hydroamination relative to three-coordinate analogues. These results establish two-coordinate plumbyliumylidenes as powerful and tunable main group Lewis acid catalysts.
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