Aluminium, one of the most common metals on Earth, has turned up in a new form that could take on jobs usually handled by expensive rare metals.

A team at King’s College London has created highly reactive aluminium molecules that can break some of the strongest chemical bonds, offering what the researchers say could be a cheaper and more sustainable alternative to metals such as platinum and palladium.

The findings were published in Nature Communications.

Led by Dr Clare Bakewell, a senior lecturer in the Department of Chemistry, the team reported the first known example of a cyclotrialumane, a compound made of three aluminium atoms arranged in a triangular structure.

According to King’s College London, that structure is unusually reactive and stays intact even when dissolved in different solutions, giving it the stability needed for a range of chemical reactions.

Those reactions include splitting dihydrogen and supporting the step-by-step insertion and chain growth of ethene, a simple two-carbon hydrocarbon.

The researchers said the work also revealed entirely new molecular structures, which could open the way to previously unknown chemical behaviour.

“Transition metals are the workhorses of chemical synthesis and catalysis, but many of the most useful are becoming increasingly difficult to access and extract, often being located in regions of political instability, increasing the demand and price,” Dr Bakewell said.

“Chemists have been looking towards more common elements from the periodic table, and we chose aluminum, as it’s super abundant, making it ~20,000 times less expensive than precious metals such as platinum and palladium.”

Dr Bakewell said the work had already gone beyond simply copying what transition metals do.

“What’s special about this work, is that we’re pushing the boundaries of chemical knowledge. Most excitingly, we can use this aluminum trimer to build completely new compounds with levels of reactivity that have never been observed before, these include the 5- and 7-membered aluminum and carbon rings formed through reaction with ethene. These capabilities go beyond the transition metals we were originally trying to mimic, to the forefront of chemical research.”

King’s College London said the chemistry could support the development of new reaction types, larger molecular structures with distinctive properties, and potentially new materials and products.

Dr Bakewell said the research was still at an early stage.

“we’re very much in the exploratory phase and we’re just at the start of beginning to unlock the capability of these earth-abundant materials,” she said.

“But from what we’ve seen already, this chemistry could support a transition to cleaner, greener and cheaper chemical production, whilst making new discoveries along the way.”

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