Hexaferrocenylbenzene: Beautiful, unlike its name

A very interesting and uniquely symmetric molecule that we came across is one called "Hexaferrocenylbenzene."

How is it unusual? Well, just look at the picture, and be awed by its symmetry.

Reminds you of a flower, doesn't it? Here's another perspective of it:

Wait! So it's great that it looks really pretty and all...but what exactly is this molecule?

Its chemical formula can be written as C₆[(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]_6. Basically, it's a benzene ring with 6 ferrocene (C10H10Fe) groups attached:

     

(Left: A picture of a benzene ring; Right: A picture of ferrocene.)

Ferrocene is also just two hydrocarbon rings (C5H5) with an iron (represented in purple) atom in the middle. This molecule also has very nice and unique symmetry.)

Just from looking at the picture, you can see just how difficult making such a crowded complicated molecule would be. That's why for decades, scientists thought that synthesizing it would be an impossible task!

Well, that claim was broken in 2006 by chemists in both the US and Denmark. 

A team of Peter Vollhardt, from the University of California at Berkeley, and other colleagues successfully synthesized this miraculous molecule. Scientists who once doubted their existence were in shock.

Vollhardt and his team also explained how it has great potential in being useful in numerous fields, such as electronics, magnetism, optics and catalysis. He also argued that this molecule can be a starting point for creating even more complicated molecules! Crazy, huh?

In addition, the team explained in their paper that the molecule was synthesized "using Negishi coupling of hexaiodidobenzene and diferrocenylzinc, usingtris(dibenzylideneacetone)dipalladium(0) as catalyst, in tetrahydrofuran."

HUH? What does that mean? The picture below explains a lot more clearly:

Essentially, in the process of "Negishi coupling," an "organozinc" molecule (a molecule that includes a carbon-zinc bond), an organic halide, and a nickel/palladium catalyst are used to create new carbon-carbon covalent bonds. And that's exactly what happened in the synthesis of the hexaferrocenylbenzene.

(A clear and brief animation of Negishi coupling)

Yet undoubtedly, the symmetry that it has definitely helped in its formation-- without such a beautifully symmetric form, the molecule would have required a substantially more complicated procedure. 

Nonetheless, with such a complicated process, no wonder so many scientists thought that it would be impossible to make!