GRAPH-THEORETICAL FORMULATION OF LONDON DIAMAGNETISM

A graph-theoretical method is presented for estimating the London diamagnetism, i.e., the diamagnetic susceptibility arising from a cyclic conjugated system of an organic compound. This method is based on the generalized version of Sachs graph-theoretical theorem, and enables one to save much labor which would otherwise be needed. Moreover, the present approach enables one to analyze London diamagnetism to extract information about the susceptibility contributions of individual TT rings in a polycyclic conjugated compound. An illustrative application to biphenylene is described in conjunction with its aromaticity. © 1979, American Chemical Society. All rights reserved.