A look at some festive structures

Happy Holidays!! 
 
This time of year, an abundance of special seasonal and holiday images surround us. Naturally, we at the Cambridge Crystallographic Data Centre want to contribute and we went on the search for festive structures within the Cambridge Structural Database (CSD) to liven up your day!
 
 
Within the CSD, we find a number of structures that embrace the festive spirit.
 
We start our journey with a tree created from the packing of α-pinene molecules (ACIFEX) with red and silver hydrogen baubles. This molecule gives a lovely fresh smell as pinene is one of the molecules responsible for the pine scent in Christmas trees. Anyone enjoying a warming glass of mulled-wine will encounter the compound Eugenol. Why? Eugenol contributes to the festive scent as a component of cloves which is an ingredient in mulled-wine, as well as a seasonal spice used in many foods and beverages. Here, in TEZZUV, we see it sitting as a guest in a beta-cyclodextrin wreath.

 

Packed alpha-pinene molecules in the space group P212121 as a spacefill model, ACIFEX (left), and an inclusion structure of eugenol in a cyclodextrin macrocycle, TEZZUV (right)
 
Holly is a common seasonal decoration here in Cambridge with the bright red berries vivid in the cold wintery mornings. These berries contain theobromine which interestingly is also contained in chocolate, something many of us overindulge in at this time of year. Yum!

 

 

One molecule of theobromine, which represents half the asymmetric unit of SEDNAQ, overlaying some holly.
 
In the structure SEDNAQ, theobromine crystallised as a dimer with two intermolecular hydrogen-bonds.  Chocolate is also a key part of traditional Yule logs and the structure with a very fitting refcode is the YULLOG structure, tetraphenylphosphinium nitro-pentacarbonyl-tungsten, although I wouldn’t advise eating this particular Yule log!
 
What else did we find in our festive structure hunt through the CSD?
 
Some other refcodes that are also getting in on the holiday season include HOLLIE and even SANTAC (laus). If SANTA C doesn’t make it round with all the presents this year perhaps SANTA D or SANTA E will be able to help out! Whatever you may be up to during the holiday season, I hope like FESTEE, the ferrocene decorated calixarene, you have plenty of festive cheer!
 
We also have refcodes that invite us to festoon our homes and workplaces with tinsel, FESTON and TINSAL; and that is something we have certainly been doing here at the CCDC.
 
 
5,11,17,23-tetrakis((ferrocenyl)ethynyl)-25,26,27,28-tetrakis(propoxy)calix(4)arene with red and gold ferrocene units, FESTEE (left), and bis(benzylmethylphenylphosphine)-tetracarbonyl-molybdenum, TINSAL (right)
 
Finally, this is a cheerful molecule that merrily has two chiral centres, and appropriately has the refcode MERRIL
The merry structure of isopropyl 2,3-dihydroxy-4-methyl-2-phenylpentanoate, MERRIL
 
 
In closing, we hope you have enjoyed our whimsical hunt through the CSD, and we wish all our users and depositors a very merry holiday season. We would love to hear which molecules you associate with this time of year on Twitter using #festivestructures.