Varied temperature sublimation of calixarene results in the formation of two distinctly different crystal structures or polymorphs alpha and beta, the latter of which is based on both,self-included' and 'back-to-back' helical arrangements of the molecule, while also being active towards CO2 sorption at room temperature and 1 atmosphere pressure.
Dalgarno, SJ., Tian, J., Warren, JE., Clark, TE., Makha, M., Raston, C., & Atwood, JL. (2007). Calixarene : a versatile sublimate that displays gas sorption properties. Chemical Communications, 46, 4848-4850. https://doi.org/10.1039/b712621b