Crystalline dendritic arylalkylsilane tetrahydrofurane inclusion complexes

Bulky arylalkylsilane dendritic macromolecules, with, respectively, 12 and 36 phenyl rings at the periphery, have been synthesized by means of a diver gent synthetic strategy. 12:cascade:silicium[4]:(silyl-2-ethylene)(1):pheny l is a first generation dendritic molecule which gives rise to an inclusion compound when recrystallized in a suitable solvent such as THF (tetrahydro furan). Single crystals of both the pure dendrimer and the P12G1/THF inclus ion compound, suitable for a comparative X-ray structural analysis, were gr own under appropriate conditions. A key feature is the nearly identical con formation of the host dendrimer molecules in the two triclinic crystalline structures determined by X-ray diffraction. Furthermore, the P12G1/THF comp ound contains two types of well-ordered solvent guest molecules located in cavities created by paired host molecules, and by the periodic stacking of these paired molecules along the a-axis. H-1 NMR, supported by solvent-dendrimer exchange reactions indicates that i nclusion compounds of higher generation dendrimers also exist, but crystals of these compounds have nor yet been obtained. (C) 1999 Elsevier Science L td. All rights reserved.