The University of Warwick and the University of Lille lead an international research initiative that has created a promising one-dimensional material using nanotube compression to change a compound’s fundamental chemistry and physics. The study was published in the Journal of the American Chemical Society.
Image Credit: University of Warwick
This study involved the nanoconfinement of a massive cluster-based compound (Cs2Mo6Br14) in a sequence of carbon nanotubes, the smallest of which was as small as 10 Ångstroms (short for Å), or one billionth of a meter.
The inside of the tube was smaller than the compounds themselves since nanotubes are so tiny. In a process known as elimination, the compound was compressed to the point of disintegration under intense confinement, forming a new, smaller compound [Mo2Br6]x inside the tube.
This research is unique and important in two different respects. In the first instance, we see how the confinement of an inorganic cluster-based material in narrow nanotubes causes that material, in a steric or confined structural limit, to eliminate or shed some of its chemicals to form a polymerized inorganic compound.
Dr Jeremy Sloan, Study Senior Author and Reader, Electron Microscopy, University of Warwick
Sloan added, “Secondly, and serendipitously, the inorganic polymer has a 1D Ising-like structure, which is of great interest in statistical physics and in forming ferromagnetic arrays with potential utility in information storage at the atomic level.”
Remarkably, the new compound’s physical properties were also completely transformed due to the confinement effect. Considered a “conga line” of compounds within the tube, the new, smaller compounds are probably magnetic and organized into a linear polymer (linked) structure.
Each compound in the conga line of compounds can only interact with its two nearest neighbors, resulting in a row of bar magnets pointing magnetically up or down. Because of the magnetic force, if their neighboring compound turns in one direction, the compound is influenced to turn the same way.
This arrangement can also be defined as a one-dimensional Ising model. Since each component can only exist in one of two states (up/down, on/off), and minor changes can ripple across the system. This binary Ising-like structure is ideal for intriguing quantum computing and molecular electronic applications.
Sloan concluded, “Our work illustrates how confining nanomaterials inside small volumes profoundly modifies their structural chemistry, while also creating scientifically interesting, and potentially functional new nanoscale objects.”
If nanoconfinement can fundamentally affect the behavior of materials and cause unforeseen transformations, such as the acquisition of electrical and magnetic capabilities, it represents a possible synthetic approach for nanomaterials with intriguing features.
This collaborative research initiative involved the University of Warwick’s Physics Department, three CNRS Institutes in Lille, Rennes, and Nantes, and Sofia University (St. Kliment Ohridksy) in Bulgaria.
This study was financed by EPSRC (U.K.) Grant No. EP/R019428/1, the French-Bulgarian PHC RILA project N° 38661ZF “EOPEN” and the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, Project No. BGRRP-2.004-0008-C01.
Journal Reference:
Faulques, E., et al. (2025) Differential Packing of Cs2Mo6Br14 Cluster-Based Halide in Variable Diameter Carbon Nanotubes with Elimination and Polymerization to 1D [Mo2Br6]x Ising Model Structures by Steric Confinement. Journal of the American Chemical Society. doi.org/10.1021/jacs.4c14883.
