Investigation of the structure and properties of several endohedral clusters and generalization of the concept of molecular topological form

The problem of structural characterization of nanoparticles and endohedral clusters is discussed. The concept of molecular topological form introduced earlier for the description and classification of stereochemical configura tions of organic molecules is generalized. The proposed definition is illus trated taking the Ca(CO)(3)(C6H6) complex and onion carbon clusters as exam ples. Topological and geometric characteristics of several multilayer fulle renes are discussed. A basis of invariants for molecular graphs of the icos ahedral onion C-60@C-240@C-540 cluster was found. This type of basis can be used for estimations of physicochemical properties of multilayer fullerene s in the topological approximation and for calculations of different topolo gical indices. The results of MNDO/PM3 simulation of molecular and electron ic structure of a hypothetical endohedral C-20@C-60 cluster are reported.