Author:

Keywords:

Science & Technology, Physical Sciences, Chemistry, Physical, Physics, Atomic, Molecular & Chemical, Chemistry, Physics, basicity, cooperative effects, molecular electrostatic potential, noncovalent interactions, siloxanes, SPIN COUPLING-CONSTANTS, N PNICOGEN BONDS, LONE-PAIR HOLE, SI-O BOND, AB-INITIO, INTERMOLECULAR INTERACTIONS, PROTON AFFINITIES, ELECTRON-DENSITY, POTENTIAL MAPS, CROWN-ETHERS, Oxygen, Silanes, Static Electricity, Siloxanes, PDMT2/21/041#56346499, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0306 Physical Chemistry (incl. Structural), 0307 Theoretical and Computational Chemistry, Chemical Physics, 3403 Macromolecular and materials chemistry, 3406 Physical chemistry

Abstract:

The basicity of the simplest silicone, disiloxane (H3 Si-O-SiH3 ), is strongly affected by the Si-O-Si angle (α). We use high-level ab initio MP2/aug'-cc-pVTZ calculations and the molecular electrostatic potential (MEP) to analyze the relationship between the increase in basicity and the reduction of α. Our results clearly point out that this increase can be explained through the MEP, as the interactions between oxygen from disiloxane and the acceptors are mostly electrostatic. Furthermore, the effect of α on the tetrel bond between disiloxane and several Lewis bases can again be rationalized using the MEP. Finally, we explore the cooperativity throughout α for ternary complexes where disiloxane simultaneously interacts with a Lewis acid and a Lewis base. Both non-covalent interactions remain cooperative for all α values, although the largest cooperativity effects are not always those maximizing the binding energy in the binary complexes. Overall, the MEP remains a powerful predictor for noncovalent interactions.