# A crystalline phosphorus-substituted borinium ion: double dihydrogen activation by an ambiphilic inorganic allene

## TL;DR

Scientists created a new borinium ion with phosphorus that can activate hydrogen without a catalyst.

## Contribution

The first isolable phosphorus-substituted borinium ion was synthesized and shown to activate dihydrogen.

## Key findings

- A monomeric ambiphilic borinium ion was successfully isolated in crystalline form.
- The compound activates dihydrogen under mild, catalyst-free conditions.
- The structure is isolobal to allene and stabilized by phosphido substituents.

## Abstract

We report the synthesis of the first monomeric, isolable ambiphilic borinium ion. Bromide abstraction from a bromo(diphosphino)borane precursor affords a two-coordinate boron cation with a structure isolobal to allene. The presence of two phosphido substituents directly bonded to the boron center provides electronic stabilization, enabling the isolation of the P-substituted borinium ion in crystalline form. This compound readily forms adducts with N-heterocyclic carbenes, yielding diphosphinoborenium ions. The ambiphilic nature of the P-substituted borinium ion is demonstrated by its ability to activate dihydrogen under mild, catalyst-free conditions, highlighting its dual Lewis acidic and basic character.

The first isolable P-substituted borinium ion has been synthesized. The obtained cation exhibits ambiphilic reactivity, enabling the activation of dihydrogen under mild, catalyst-free conditions.