Thursday, 1 March 2012

Blind Chemist: Resonance, Renaissance and Reminisces

Update 28/3/2012

Chemistry World (March 2012, Volume 9 Number 3) had an interesting article titled “Fast NMR shows the way” and written by Philip Robinson about developments in NMR.  It was pleasing to note that my old university, Edinburgh, is still playing a part in this fascinating technique.  Dusan Uhrin, a lecturer in NMR at the university, was interviewed along with Professor Chris Moody at Nottingham and Patrick Giraudeau at the University of Nantes among others.  The developments stem from the work done by Lucio Frydman at the Weizmann Institute of Science in Israel.  These focus on real time intermediates in some chemical reactions.

In turning back the clock to the mid-1970s, a younger Professor Whitestick (who was sighted) had researched reaction mechanisms in phosphorus compounds to make a designer fluorophosphine.  The section of the phosphorus nmr spectrum is shown below.  This was obtained over a weekend with the five millimetre nmr tube (sealed under vacuum) at -78 degrees centigrade.  This was achieved in a dry ice/carbon dioxide-acetone slush bath.

*** end of update

My reduced mobility has cut some of my spontaneous trips or in other words I have to plan ahead.  Some of my trips to meetings have been curtailed and as I am on a waiting list for some hip surgery I have not booked ahead too far and rely on a network of friends both in London and on Twitter for some practical help and ideas. 

I mentioned in the blog and on Twitter how useful Twitter is for the visually impaired.  It allows almost real time access to people once you have their twitter address.  One of my tweets about being able to mix science and art got several tweets and retweets and lasted over 24 hours.  In my recent posts on the Royal Academy and the National Gallery I commented on the amount of chemistry involved in pigments.  The Wellcome encourages the meeting of the Arts and the Sciences and I have never understood why barriers are erected in these fields. 

There was an inorganic chemical elemental list in my twitter feed and I have summarised this using twitter names.  This illustrates how practical this social medium can be. 

Starting off with a programme on Radio3, Nightwaves.  During an interview with Peter Ackroyd on Wilkie Collins, Matthew Sweet was discussing the use of silver nitrate (AgNO3) in a “cure” for epilepsy in Miss Finch.  It was said to be agony which it almost is.  Pittso was tweeting from the Forth Bridge and I mentioned the painting of a landscape using lead, chrome and cobalt based pigments. (Painting the Forth Bridge used to take 3 years and the coating only lasted 3 years so the job was never finished.)  RNIB and Insight Radio tweeted about the visually impaired and social media and I tweeted my Corot post with a reply.  Hywel Jones tweeted about hip implants and mentioned chrome and cobalt ions.  We got into serious chemistry, with an exchange with S_J_Lancaster and JessTheChemist about nuclear magnetic resonance and some chemistry involving fluorine, phosphorus and carbon 13. 

Many chemists are creative and it comes with creating new molecules and observing them and measuring them.  Some understanding of physics and mathematics are essential and chemistry is still a practical science in that other skills have to be learned in a 3 year PhD programme.  Glass blowing, high vacuum techniques, cryogenics and spectroscopy were all useful ancillary subjects to the synthesis of novel compounds.  Given a 40 stage reaction sequence any chemist worth their salt would seek to both increase the yield and cut the steps. 

This often transferred to cooking and I remember following a recipe for apfelstrudel exactly with perfect results only to follow and repeat by adapting the recipe, with disastrous results.  I can “see” the charred apple goo in the base of the oven yet.  We used to joke about a reaction which was a bit “slow” Usually a reaction can be made to go faster by heating it, increasing the pressure, finding a catalyst and even flashing a light at it.  The latter was known as giving it a bit of RF or eeven h gnu (For the benefit of those using a screenreader like myself gnu stands for a Greek letter meaning frequency with h being Plancks constant)

In the case of nmr the molecule is left in a probe in a magnetic field and a bit of RF (radio frequency) is beamed.  Certain atoms have a “spin” value of a fraction usually + or – ½ and this results in a pretty nmr spectrum.  Common isotopes of hydrogen, fluorine and phosphorus have spin ½ and molecules having several fluorine (F) phosphorus (P) and hydrogen (H or proton) can be first synthesised in a thought experiment (in the bar) and made in real life.  Organic chemists were usually adding methyl groups all the time whereas we inorganic chemists were a bit more creative and used to handling new chemical systems. 

Nuclear Magnetic Resonance is all around in many hospitals and I was in an MRI scanner (they dropped the nuclear so as not to frighten the horses) in January for the best part of an hour.  I was put on a conveyor belt (that’s what it felt like) and the scanner was wrapped round me.  I was given a set of headphones and the machine was grunting and humming and I thought about my created molecules laughing at me as I was “given a bit of RF) in a magnetic field. The nmr of hydrogen is often known as pmr or proton magnetic resonance.  The nmr spectra in simple molecules can be very attractive and the patterns can be predicted and often novel compounds were synthesised first on the basis of the design of both the molecule and the spectrum expected.  If you want to find out more on nmr there are some terms such as :chemical shift, coupling constant, nuclear Overhauser Effect and spin tickling which can be searched.  Albert Overhauser was a researcher in nmr and he died at the end of 2011. 

Some of my spectra have been shown in the blog and these would be useful in a tactile format for the understanding of nmr in undergraduate chemistry or even in school.  One of my paintings was intended to resemble the Chagall stained glass window in Chichester Cathedral.  I have attached an image for the blog and I am placing it with some electron charge pictures recently sent to me by a chemistry teacher DexNott. 

After Chagall Window, Chichester
© Prof Whitestick
(Note: under direction of Val Fox, who took the image of my painting and has helped me paint the edges including parts of her hand as she was preparing to go to a private view!)
The positive and negative charged arms of X-shaped naphthalocyanine can be clearly seen, and compare well with theoretic charge distribution images
Image © IBM Research-Zurich

(More information on this can be obtained from the BBC website via

Phosphorus 31P nmr spectrum
© Prof Whitestick

(These spectra were taken from my PhD thesis.  This was before word processors were common and computers were limited to card and tape readers.  The thesis itself was typed on an office typewriter and is double spaced and single side.  There is no colour and as this is probably the only image which is totally inaccessible to me, I will not be making a habit of using it.  It's only to show how those with visual impairments can have access to some of the more complex sciences.)

If you ever have to have an mri scan think of my research work which was done in the 1970s just when Fourier Transform, supercooled conductors and computing with pulse nmr was in relative infancy as a technique.  Pure science is not done with an end use in mind so in that form it is an art.