MOLECULAR-FORCE FIELD-STUDY CONCERNING THE HOST PROPERTIES OF CARBOSILANE DENDRIMERS

The effect of structural variations at the core of carbosilane dendrim ers has been studied using Molecular Dynamics. Several derivatives of the parent dendrimer have been modeled and characterized with respect to the dimensions of the inner cavities which lie on the order of 5-15 Angstrom. The ''denseness'' of the outer shell has been studied by ca lculating solvent accessible surfaces and excluded volumes as a functi on of the radius of the probe sphere. The higher generation dendrimers were found to possess dense outer shells with holes of the order of 2 -3 Angstrom. Dendron separation especially with respect to clefts in t he molecule is discussed. It was found that in low generation carbosil ane dendrimers the dendrons are clearly separated while at higher gene rations a substantial amount of interpenetration occurs. In addition, results are presented showing that carbosilane dendrimer surfaces are fractal only over a narrow range of length scales. In this range, the fractal dimensions of the surfaces are of the order of 2.1.