Modelling the diamagnetic susceptibility of organic compounds by a sub-structural graph-theoretical approach

Diamagnetic susceptibilities of two series of organic compounds have been described by using a novel sub-structural approach. The method is based on the calculation of spectral moments of the bond adjacency matrix of molecular graphs. These spectral moments are expressed via algebraic expressions as linear combinations of simple fragments present in molecules. Contributions of each fragment to the diamagnetic susceptibility of alkanes and alkyl halides were obtained by using this approach. Quantitative models found are significant from a statistical point of view and they permit a clear interpretation of the studied property in terms of the structural features of molecules.