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Updated: Jan 7, 2026

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Phosphonium Ionic Imine Cage with an Uncommon Tri24Di6 Topology for Selective Capture of Propyne in Propyne/Propylene
Aiting Kai1,2, Siyuan Yang1,2, Dingyue Hu1
1Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
Abstract:
The incorporation of phosphine units into porous organic cages (POCs) imparts the rich chemistry of phosphorus atoms to the POC system and enables a range of relevant applications. However, phosphine-containing POCs remain underexplored. In this work, quaternary phosphonium ionic cages were successfully constructed via the integration of phosphine groups, where premethylation and anion exchange of the triphenylphosphine (PPh3)-aldehyde precursor were employed before the imine condensation reaction. The counterions of the PPh3-aldehyde precursor were found to play a crucial role in dictating the topology of the resulting cage product. While the precursor bearing an iodide (I-) anion yielded a soluble [2 + 3] cage P-cage-I, the bis(trifluoromethane)sulfonimide (NTf2-) and hexafluorophosphate (PF6-) analogues (P-cage-NTf2 and P-cage-PF6) formed [4 + 6] assemblies with the rare Tri24Di6 (nomenclature for porous organic cage topology classification). Benefiting from the synergistic effects of a favorable topology, flexible windows, and guest-affinitive anions in the Tri24Di6 cage structure, P-cage-PF6 demonstrated excellent propyne/propylene separation performance, as confirmed by breakthrough experiments.
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