Structure and bonding in triorganotin chlorides: a perspective from energy decomposition analysis

The Sn-Cl chemical bond of four organotin halides (Me3SnCl, Et3SnCl, Bu3SnCl, and Ph3SnCl) was studied by using relativistic density functional theory in combination with a quantitative energy decomposition analysis to explain the formation of charged species. The sigma orbital is the dominant contributor to the stabilization of the Sn-Cl bond, and the pi-orbital interactions also have a significant contribution to the stabilization of Ph3Sn+ cation when the aromatic groups are bonded to the tin atom. The aromaticity of the phenyl groups delocalizes the positive charge, donating electrons to tin atom by conjugation. Although Me3SnCl and Ph3SnCl are constituted by groups which the size of the substituents is different, the interaction energies obtained with the energy decomposition analysis present similar values, which also occur with the thermodynamic parameters.