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 topological index H₁ was introduced in the paper to investigate the diamagnetic susceptibility of the organometallics for the first time, which is essentially a kind of edge-weighted one in terms of the graph theory. The indices Hi's of the alkyl-IVA group organometallic halides, including halogen-substituted methanes and enthanes along with those represented by (CH₃)₄-nMXn (n = 0-4; M = Si, Ge, Sn), were calculated accordingly. Good linear relations were found between the H₁'s and the corresponding diamagnetic susceptibilities %M's for each series of compounds with similar graphic representations. Moreover, estimation of %m's was made as to the compounds whose values are not experimentally measured yet.