Breaking a Dative Bond with Mechanical Forces

Abstract Bond breaking and forming is essential in every chemical reaction. Here, we report a single dative bond breaking process revealing an unprecedented level of detail using noncontact atomic force microscopy. The dative bond between carbon monoxide and ferrous phthalocyanine was ruptured via mechanical forces applied by atomic force microscope tips; the process was quantitatively measured and characterized both experimentally and via first principles quantum mechanics modeling. Our results show that the bond can be ruptured either by applying an attractive force of ~150 pN (pulling) or by a repulsive force of ~220 pN (pushing), accompanied by changes of the spin state of the system. Our combined experimental and computational studies provide a deeper understanding of the chemical bond breaking process.