Lack of co-crystal formation with cyclotriphosphazenes : a cautionary tale
CITATION: Wahl, H., Haynes, D. A. & Le Roex, T. 2016. Lack of co-crystal formation with cyclotriphosphazenes : a cautionary tale. South African Journal of Chemistry, 69:35–43, doi:10.17159/0379-4350/2016/v69a5.
The original publication is available at http://www.scielo.org.za
ENGLISH ABSTRACT: The attempted formation of co-crystals with a series of cyclotriphosphazene derivatives has been investigated. Despite numerous attempts, only one co-crystal was obtained. The crystal structure of this material, [hexakis(4-pyridyloxy)-cyclotriphosphazene][ terephthalic acid]2.5, is presented here. The crystal structures of 2,2-bis(4-formylphenoxy)-4,4,6,6-bis[spiro(2’,2”-dioxy- 1’,1”-biphenylyl]cyclo-triphosphazene and hexakis(4-cyanophenoxy)cyclotriphosphazene are also reported for the first time. The extremely low rate of co-crystal occurrence in these materials cannot be explained, despite the consideration of several possibilities. This serves as a cautionary tale – co-crystal formation is not necessarily straightforward.