2D-Map of Intermolecular Interactions in Organic Chemistry Reveals Underrepresented Area of Research

The molecular orbital (MO) theory is an indispensable model to describe the interaction between two molecular species, particularly during chemical bond formation. Here we show that by plotting the energy difference (E_DA) of the HOMO of an electron donor and the LUMO of an acceptor against their overlap integral (S_DA), many similar types of bimolecular interactions tend to be clustered near one another on the 2D map. Interestingly, in one of the six arbitrarily divided sections designated as “B2”, the interacting molecular pairs appear to present a type of interaction as a “hybrid” between chemical reaction and radical pair formation, a lesser explored area of research. We propose that such interactions could be crucial for the development of materials with unique optical, magnetic, and catalytic properties from purely organic molecules.