Polymorphism through Desolvation of the Solvates of a van der Waals Host

2,4,6-Triethyl-1,3,5-tris(phenoxymethyl)benzene (1H), a van der Waals host molecule, forms 10 solvates with 1,4-dioxane (DXN), p-xylene (PXL), pyridine (PYD), chloroform (CLF), tetrachloromethane (TCM), tetrahydrofuran (THF), benzene (BEN), and ethyl acetate (EAC), which exhibit conversion to three different phases upon desolvation. Crystal structures of two of the guest-free phases were identified by producing single crystals of 1H from acetonitrile and ethyl acetate solutions. These two forms are converted to the third form upon heating. The third phase is also obtained after desolvation of the 1,4-dioxane solvate, but no single crystals corresponding to this phase could be isolated. Crystallization from THF and TCM produced two different solvates concomitantly in each case, whereas the EAC solution of 1H concomitantly produced the guest-free form II as well as minor quantities of a solvate. One of the THF solvates is isostructural to the CLF solvate, and the other THF solvate is isostructural to one of the TCM solvates.