Encapsulation and Polymerization of White Phosphorus Inside Single‐Wall Carbon Nanotubes

• Published in: Angewandte Chemie International Edition Vol. 56; no. 28; pp. 8144 - 8148
• Main Authors: Hart, Martin, White, Edward R., Chen, Ji, McGilvery, Catriona M., Pickard, Chris J., Michaelides, Angelos, Sella, Andrea, Shaffer, Milo S. P., Salzmann, Christoph G.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 03.07.2017
• Edition: International ed. in English
• Subjects: Allotropy; Atomic structure; Chains (polymeric); density functional calculations; Electron microscopy; Encapsulation; Exothermic reactions; Nanotechnology; Nanotubes; Phosphorus; Physical properties; Polymerization; Single wall carbon nanotubes; Transmission electron microscopy; density functional calculations; nanotubes; polymerization; allotropy; phosphorus
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201703585

Elemental phosphorus displays an impressive number of allotropes with highly diverse chemical and physical properties. White phosphorus has now been filled into single‐wall carbon nanotubes (SWCNTs) from the liquid and thereby stabilized against the highly exothermic reaction with atmospheric oxygen. The encapsulated tetraphosphorus molecules were visualized with transmission electron microscopy, but found to convert readily into chain structures inside the SWCNT “nanoreactors”. The energies of the possible chain structures were determined computationally, highlighting a delicate balance between the extent of polymerization and the SWCNT diameter. Experimentally, a single‐stranded zig‐zag chain of phosphorus atoms was observed, which is the lowest energy structure at small confinement diameters. These one‐dimensional chains provide a glimpse into the very first steps of the transformation from white to red phosphorus. Putting peas into a pod: Tetrahedral P4 molecules can be assembled inside single wall carbon nanotubes to give air‐stable constructs. The encapsulated molecules show a tendency to polymerize, giving rise to range of possible chain structures, including a zig‐zag chain of individual atoms. These one‐dimensional allotropes provide the first direct glimpse into the transformation from white to red phosphorus.