  The dynamics of a localized molecular spin under the influence of external
voltage pulses is addressed using a generalized spin equation of motion. The
approach incorporates anisotropic fields, non-equilibrium conditions, and
non-adiabatic dynamics. By application of a voltage pulse of temporal length
$\tau$, a recurring $4\pi$-periodic switching of the localized spin is
observed. The switching phenomena can be explained by dynamical exchange
interactions, internal transient fields, and self-interactions acting on the
localized spin moment.
