A valentine-related review of the Cambridge Structural Database
February 13, 2015
This week’s blog has a valentine’s theme. Some of you may ask what the Cambridge Structural Database (CSD) has to do with romance…well the link is tenuous, but love and romance are all about chemistry!! Of course, this creates the perfect excuse to explore Valentines related crystal structures in the CSD.
Personally, I never need an excuse to eat chocolate, but many associate it with holidays, particularly Valentine’s Day. Let’s look at chocolate from a molecular perspective. Cocoa butter (or more precisely the triglyceride fats within it) has six polymorphic forms [1-3]. The formation of chocolate bloom, the white spots on chocolate, is in part due to a polymorphic transformation from Form V to Form VI – the thermodynamically more stable polymorph. Chocolate tempering is the process of heating and cooling the chocolate to crystallize the Form V polymorph, giving chocolate its pleasant mouth sensation. Yum! Two examples from the CSD are refcodes JEMRUP and JEMSAW, which are triglyceride polymorphs found in cocoa butter.
What does this have to do with love? The reason we associate chocolate with love is that many believe it to have aphrodisiac properties. While that link hasn’t been proved, there are quite a few alkaloids in chocolate that may have a positive physiological effect; Theobromine ( SEDNAQ ) being the most studied. Interestingly, it forms quite a few metal complexes, salts and co-crystals (e.g. MUPPET) which makes it a good drug delivery platform; better still is a Quercetin based co-crystal (MUPPOD). Quercetin is a flavonoid found in red wine, so a co-crystal with theobromine would make the perfect gift!!
In closing, we all know that love and romance require human chemistry, but real chemistry is all about molecular structure! For the last fifty years the CSD, which now contains over 750,000-curated structures has offered the most comprehensive source of structural chemistry information in the world.
For those who might benefit, here is a shopping list, but you had better be quick!