MOLECULAR TOPOLOGICAL INDEX AND ITS APPLICATION .4. RELATIONSHIPS WITH THE DIAMAGNETIC SUSCEPTIBILITIES OF ALKYL-IVA GROUP ORGANOMETALLIC HALIDES

On the basis of four-energy-level model proposed previously, a new top ological index H-1 was introduced in the paper to investigate the diam agnetic susceptibility of the organometallics for the first time, whic h is essentially a kind of edge-weighted one in terms of the graph the ory. The indices H-1's of the alkyl-IVA group organometallic halides, including halogen-substituted methanes and enthanes along with those r epresented by (CH3)(4)-(n)MX(n) (n = 0-4; M = Si, Ge, Sn), were calcul ated accordingly. Good linear relations were found between the H-1's a nd the corresponding diamagnetic susceptibilities chi(M)'s for each se ries of compounds with similar graphic representations. Moreover, esti mation of chi(M)'s was made as to the compounds whose values are not e xperimentally measured yet.