Exploiting Octahedral Stereocenters: From Enzyme Inhibition to Asymmetric Photoredox Catalysis #chempaperaday 290

Great essay on the importance of octahedral metal centers and how they can be used for many many applications. I think people often ignore the metal and focus on the chirality of the ligands especially for enantioselective catalysis. But here you can see a different approach highlighting simple coordination chemistry. 

 

http://onlinelibrary.wiley.com/doi/10.1002/anie.201612516/epdf

The Anion of Zeise's Salt #chempaperaday 251

Zeise's Salt is accepted as the first organometallic compound and it was prepared by William Christopher Zeise. Before talking about his life, let's see what this salt is. Apparently, Zeise first prepared this compound in 1825, but it did not draw much attention. In 1830, he publishes a detailed paper on the synthesis and properties of this interesting "brown residue". He does some analytical work in addition to adding KCl to the compound and names the salt as "inflammatory potassium platinum salt". He was one of those early chemists who tastes his compounds and now we know that it tastes as "metallic, astringent, long lasting".

A few years later, he was challenged by the famous Justus Liebig. Liebig doesn't believe the composition of the compound and suggests that it contain oxygen. He believes that the compound has an alkoxy group. Zeise does more analytical work and shows that there is no oxygen but of course Liebig was not convinced and writes a paper in reply to Zeise.

15 years later, Karl Birnbaum repeats Zeise's experiments and determines that his formulation is correct. The crystal structure of Zeise's salt was first solved in 1954 and you can see a representation below. For the untrained person, coordination mode of olefin is really weird. For an inorganic chemist, it is perfectly fine. I will write another post on the bonding and molecular orbital diagram of this compound soon, so I am moving on to Zeise's life now.

To be honest, I only knew Zeise by his famous compound. To my surprise, he turned out to be one of the greatest chemists ever! His research was focused on chemistry of sulfur and he discovered xanthates and thiols! He also tried to study components of tobacco smoke!

It turns out he did most of his experiments at home and his cats were killed by his landlord due to a terrible smell. In fact, he was even removed from a play because he smelled so bad.

What a character, what a chemist. This short but fantastic article really urged me to read more about Zeise. I've just started to collect some papers now.

* all images are from wikipedia pages for Zeise's salt and Zeise himself.

Complexes of Carbon Monoxide and Its Relatives #chempaperaday 248

This is a review article written for the 100th year anniversary of the synthesis of nickel tetracarbonyl. The author is one of the greatest chemists ever (IMO) Helmut Werner. I will probably write another post focused on his research and contributions to let people know what he did.

Since the article is about CO complexes, here you can read more about CO analogues and isoelectronic ligands and their coordination properties. It looks like it's open access, so I hope everyone will be able to read it. A fantastic review of coordination chemistry of CO and its analogues with a lot of historically important names and papers.

Is CO a Special Ligand in Organometallic Chemistry? #chempaperaday 247

As I mentioned in a recent post, I have been reading a lot of Hoffmann papers to study and learn more about MO theory. So, be ready if I post several of them in the next couple weeks. 

Transition metal carbonyl complexes are very important in organometallic chemistry.  Sometimes they are used as catalysts or precursor to catalysts, and sometimes they are used to explain our understanding of important industrial processes like Fischer-Tropsch synthesis. 

It looks like CO is very special in terms of sigma donating and pi accepting capabilities. But why? Is it unique? Can we find better ligands? This paper is probably the first of the series I'll post where I am trying to find an answer (not experimentally, just by reading literature). So, if you follow the series, you will probably learn a lot with me.