Borane‐Stabilized Isomeric Dimers of the Phosphaethynolate Anion

Abstract

AbstractThe reactions of the phosphaethynolate anion ([PCO]−) with a range of boranes were explored. BPh3 and [PCO]− form a dimeric anion featuring P−B bonds and is prone to dissociation at room temperature. The more Lewis acidic borane B(C6F5)3 yields a less symmetric dimer of [PCO]− with P−B and P−O bonds. Less sterically demanding HB(C6F5)2 and H2B(C6F5) boranes form a third isomer with [PCO]− featuring both boranes bound to the same phosphorus atom. Despite the unexpected thermodynamic preference for P‐coordination, computational data illustrate that electronic and steric features impact the binding modes of the resulting dianionic dimers.