Effective Bond-Strength Indicators

Abstract

To save time and computer resources, we made an attempt to design reasonable yet simple structural indicators to identify weak chemical bonds, instead of performing numerous, tedious calculations of individual bond dissociation energies (BDEs) for all bonds within a molecule. Based on the commonly available structure-property indicators for bond strength, such as bond length (R), the Mulliken interatomic electron number (MIEN), the Wiberg bond order (WBO), and BDE, we have created two new bond-strength indicators, i.e., M = MIEN/R and K = (WBO × MIEN)/R2, which shall be directly used to efficiently identify almost all weak bonds with BDE below 350 kJ/mol. If several bonds of the same type attain the same smallest values of M or K, values of the electron density at the bond critical points (ρ c ) alone can almost always pinpoint the weakest bond from the set of weak bonds, greatly reducing the amount of efforts in carrying out the calculations of the BDEs of the corresponding bonds.