Theoretical study on open-shell electronic structures of through-bond/ through-space hybrid conjugated ladder graphs

In this study, we theoretically investigated open -shell electronic structures of face-to-face pi-stacked n-mers of diradicaloids with through-bond/through-space (TB/TS) hybrid conjugation structure of n -ladder graphs. Based on the Huckel theory and the valence bond (VB) picture of diradical character (y), we considered y for the local TB and TS interactions, yTB and yTS, and derived sets of conditions between yTB and yTS when y of the entire system, y(n), takes the maximum for a given n. The approximate relations betweenyTB, yTS, and y(n) help predict the open -shell electronic structures of face-to-face pi-stacked n-mers of realistic diradicaloids with different yTB.