Topologically rational assembly of polyradicals

We present topologically rational assembly of polyradicals (TRAP) to tailor electronic structure of organic π-conjugated compounds, including polycyclic aromatic hydrocarbons, aromatic heterocycles, extended nanographenes and doped planar systems applicable in organic electronics, spintronics, single-molecule junctions and molecular devices. The method is devised by connecting the wavefunction theory in valence bond formulation and the topology of the π-conjugated system to engineer the spin-state ordering and energy gaps in low-energy spectra of designed polyradicals. In TRAP method, the starting determinative underlying feature of the π-conjugated system is the topology of connectivity of the atoms with available p_z orbitals and other factors modulate the landscape of possible properties upon rational design to increase the contribution of particular electronic configuration(s). Within our model, we propose a generalized Clar's rule for estimating relative contributions of various valence bond forms into the ground-state wavefunction according to optimal partition of the π-system into non-aromatic and local aromatic units to maximize the total π-binding energy, and extend Ovchinnikov's rule to predict the ground-state multiplicity of non-alternant systems.