The 2017 meeting of the American Crystallographic Association was held in New Orleans from May 26th – 30th. The meeting boasted a packed program featuring lectures, workshops, and poster sessions by range of international presenters from both academia and industry. The CrystEngComm poster prize was awarded to Raúl Castañeda, for his poster Co-Crystals of Dithieno[3,2-a:2′,3′-c]phenazine Derivatives and Trimeric Perfluoro-ortho-Phenylene Mercury.
Raúl was presenting work that he carried out while working towards a Master’s degree with Tatiana Timofeeva at New Mexico Highlands University. Raul’s work focused on studying halogen bonding in compounds for application as inorganic electronics:
Dithienophenazine derivatives are molecules recently synthesized from different groups in attempt to apply them to inorganic electronics. Our group recently synthesized five different derivatives with dithieno[3,2-a:2′,3′-c]phenazine (DTPhz) with equal substituents at 9 and 10 position (H, F, Cl, Br) or pyrido[2,3-b]dithieno[3,2-f:2′,3′-h]quinoxaline (8N-DTPhz). These molecules are very similar in their electronic properties because they have similar band gaps and HOMO levels, but different dipole moments between the halogen derivatives and the non-halogen derivatives. Being very similar as donors make them very good examples to study halogen bonding in donor-acceptor co-crystals with a fully perfluorinated acceptor such as trimeric perfluoro-ortho-phenylene mercury (TPPM). Halogen bonding was important in these co-crystals, since only the donors with halogen substituents lead to co-crystals with mixed donor-acceptor stacks. Unsubstituted DTPhz do not gave co-crystals, and 8N-DTPhz gave a co-crystal where water is blocking one side of the acceptor. The four structures obtained underline the importance of halogen bonding in donor-acceptor co-crystals, as well the impact of different halogens in crystal packing.
Raúl is originally from Chihuahua, Mexico, where he carried out his Bachelor’s degree before moving to the US to study for his Master’s. He then continued moving north to Canada where he is currently pursuing his PhD with Jaclyn Brusso at the University of Ottawa. Besides crystallography, he enjoys playing clarinet for a community band in Gatineau Quebec.