Transition metal catalysts are formidable tools towards greener chemistry, allowing for low-waste, energy-efficient, and selective reactions. However, the noble metals (Ru, Os, Rh, Ir, Pd, Pt) that are currently most common in homogeneous catalysts suffer from high toxicity and environmental impact in addition to their scarcity and ensuing high cost. First-row metals (Mn, Fe, Co, Ni, Cu) are emerg ...