Sc-Cr Metal complexes open benzene ring

[Astronuc]

https://cen.acs.org/physical-chemis...3/web/2025/07?sc=250723_sc_eng_fb_cen_boosted

Benzene’s aromaticity makes it a tough nut to crack, and there are very few ways to convert it into linear products under mild conditions, says Jiaxiang Chu of the University of Chinese Academy of Sciences, who led the experimental aspects of the work.

Back in 2019, for example, a team led by Simon Aldridge at the University of Oxford made an aluminum complex that inserts itself into benzene, priming it for a reaction with a tin reagent that breaks open the ring. In addition, certain enzymes can pry open the benzene ring in catechol.

The team behind the new study instead drew inspiration from the kinds of metal complexes that can break the strong bonds in dinitrogen or carbon monoxide. First they made a scandium complex containing a pincer-like ligand that stabilizes a range of metal oxidation states. Then they mixed the complex with potassium graphite (KC8), which is a strong reducing agent, and benzene at room temperature. This formed an inverted sandwich complex in which each of benzene’s faces binds to a scandium complex. In this arrangement, the benzene carries four extra electrons in its antibonding orbitals.

“Scandium is always good for a surprise because it’s one of the smallest, highest-charged metal cations,” says Sjoerd Harder of Friedrich Alexander University Erlangen-Nuremberg, an organometallic chemist who uses main-group metal complexes to activate strong bonds. Harder was not involved in the new work. “It can do stuff that other metals can’t do.”

 

[Mayhem]

It is always interesting to see Scandium getting applied.

We inorganic chemists sometimes forget that the first row doesn't start at titanium!

 

[Astronuc]

Sc and Y are interesting elements.

Sc is a useful strengthener in Al. Sc is also very expensive given that is produced in few mines.

https://en.wikipedia.org/wiki/Scandium#Applications

https://pubsapp.acs.org/cen/80th/print/scandium.html
https://periodic-table.rsc.org/element/21/scandium

https://www.aemree.com/news/interesting-facts-about-scandium.html


I wonder if it Sc-Cr oomplexes could degrade/decompose polyaromatic compounds, e.g., PCBs, biphenyls, triphenyls, etc.

 

[Mayhem]

I havent perused the article, but their illustrations suggest that the benzene ring coordinates axially to the Sc/Sc active site. I am not sure how well polyaromatics can emulate this.