6. Designing and Understanding Building Blocks for Molecular Spintronics

Designing and understanding spin coupling within and between molecules is important for, e.g., nanoscale spintronics, magnetic materials, catalysis, and biochemistry. We review a recently developed approach to analyzing spin coupling in terms of local pathways, which allows to evaluate how much each part of a structure contributes to coupling, and present examples of how first-principles electronic structure theory can help to understand spin coupling in molecular systems which show the potential for photo- or redoxswitching, or where the ground state is stabilized with respect to spin flips by adding unpaired spins on a bridge connecting two spin centers. Finally, we make a connection between spin coupling and conductance through molecular bridges.