<em>Bisem>(imino)pyridyl iron(II) complexes possess the catalytic activity within ethylene polymerization.
The catalytic polymerization is controlled by the spin-dependent effects.
The driving force of spin-dependent catalysis is the spin-orbit coupling (SOC).
The activation barrier for the catalytic ethylene polymerization has the spin-dependent origin.
The external magnetic field affect on the catalytic ethylene polymerization.