Two-headed chemical mayhem!

Sunday, February 18, 2007

Interesting chemistry articles

So I thought I might post something chemistry-related - something I haven't done in a while. Below are three papers I have read recently.
After reading almost any of Fujita's papers, I always think to myself "wish I would have published that". His work is simple (in theory), which gives it an intangible elegance. Here (J. Am. Chem. Soc. 2007, 129, 1850) he uses light to labilise his Pt-pyridyl metallocyclic systems to give the thermodynamically more stable (due to hydrophobic effects/pi-pi stacking) catenated dimers. This takes only minutes under UV light, whereas days are required if it's heated instead. Not a new concept, but nice application and mechanistic insight (photochemical mechanism is dissociative, thermal one is associative, which is of course most common for square-planar complexes).
Another cool paper, also in the field of coordination chemistry, is a recent review by Nitschke (Acc. Chem. Res. 2007, 40, 103) highlighting some nice dynamic combinatorial-style work. Most people (myself included) just abhor the prospect of a mixture of products from a reaction - this guy (who, like many top supramolecular chemists, is of the Lehn pedigree) loves them! Anyway, the point of this work is that, unlike Sanders or Fujita (whose work primarily uses labile covalent and coordination bonds, respectively) Nitschke uses a bunch of very labile interactions and can, depending on the product distribution, quantify and rationalise these contributions.
I'll finish with a paper published by none other than F. Albert Cotton, who recently passed away at the age of 76. The guy was a powerhouse of inorganic chemistry and most undergrads would have consulted Advanced Inorganic Chemistry (co-authored by the Nobel Laureate Geoffrey Wilkinson) at least once during their studies. A 2006 Dalton paper from Cottons group (Dalton Trans. 2006, 3900) is a great read and is perhaps the most thorough analysis of a square/triangle equilibrium to date. The crystallisation of the square and triangle components, along with their X-ray and NMR characterisation (they can each be dissolved and an NMR spectrum acquired before substantial interconversion) allowed for the mixture to be analysed quite simply. While many people give a half-arsed argument when considering such equilibria (triangle formation leads to an entropy increase, due to the formation of more particles, but is higher in enthalpy owing to angle/steric strain) Cotton has done all the work and gets all the thermodynamic numbers out. Full marks to him!

Peace out,

-Bkr

8 Comments:

Anonymous all the cool people are on level 4 said...

Ahhh beaker, you continue to delight and illuminate us all:) Although I thought you were going to actually dedicate the post to me, so I'm a little upset...

1:24 PM  
Blogger Bunsen and Beaker said...

Fret not, my fellow level 4 resident, for your time will come...perhaps in a post or two =)

7:34 PM  
Anonymous FOJ said...

Nice work! I bet all that reading kept your mind off the 20% that olympia resources fell yesterday!

I wonder how many complexes fujita stuck under a mercury lamp (or other lamps for that matter) until he got one to work...

6:17 AM  
Anonymous bkr said...

...dammit, you're right...that's the last time I ever buy any shares =(

8:09 AM  
Blogger pip said...

huh?

3:10 PM  
Blogger Bunsen and Beaker said...

sorry for all the chemistry in this post pip...I'll make sure to make future posts devoid of chemistry in order to please you :)

3:28 PM  
Anonymous Anonymous said...

I have a mechanism related question. What is the mechanism for the conversion of a primary alcohol to an alkyl iodide using triphenylphosphine, iodine and imidazole?

Cheers,

Sam

8:13 PM  
Anonymous Anonymous said...

Cotton was considered a bastard. To think people give him credit for other people's work. You've been brainwashed by the system to associate the ideas and efforts of hundreds of people with one man.

Dictionary

Bastard- see EJ COREY.

9:18 AM  

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