Clathrate Engineering of Piedfort Hosts. Crystal Structures and Molecular Modeling of the <i>para-mono</i>- and <i>meta</i>-di-methy1/<i>t</i>-buty1 Substituted Derivatives of 2,4,6-tris (alkylphenoxy)-1,3,5-triazine

Abstract

Abstract X-ray crystal structure analyses of four related 2,4,6-tris-(alkylphenoxy)-1,3,5-triazine host candidates were planned to clarify conditions of the Piedfort pair based inclusion formation. The 3,5-di-t-butyl-phenoxy substituted compound yields inclusion and exhibits dimorphism as well. Contrasting the inclusion, no Piedfort pairing was observed in the dimorphs. Other para- and meta-t-buty1/methy1 substituted molecules did not give clathrates. Homomolecular columns of polymeric Piedfort stacks were formed instead. The stacking distances between triazine rings in the polymeric columns vary smoothly with the size and position of the substituents. We conclude that bulky substituents must impede parallel to the expected direction of favorable Piedfort stacking to form inclusion supramolecules.