Theoretical calculation of the adiabatic electron affinities of the monosubstituted benzaldehyde derivatives

Abstract

In the current study, several computational models were examined to calculate accurate adiabatic electron affinity (AEA) of twelve m- and p-monosubstituted benzaldehyde derivatives. The examined models are as follows: (i) composite high-level ab initio (G3B3, G4, CBS-Q, and CBS-QB3), (ii) Three hybrid DFT approaches (B3LYP, CAM-B3LYP, and wB97XD) with two basis sets (6–31 + G(d,p) and 6–311++G(2df,2p)) and (iii) single point calculation using fifteen DFT approaches with 6–311++G(2df,2p) at the B3LYP/6–31 + G(d,p) geometry. Several statistical descriptors were computed to validate the calculated AEAs based on the available experimental results. Results revealed that G3B3 and CBS-QB3 are the most accurate result, while G4 and CBS-Q methods yield less accurate ones. Also, the wB97XD and CAM-B3LYP in combination with 6–311++G(2df,2p) able to calculate accurate AEAs. Low CPU time single point calculation strategy by using wb97 and wb97X approaches can compute AEAs value as accurately as G3B3 and CBS-QB3 methods. The AEAs of other several monosubstituted benzaldehydes were also predicted by using the wb97, wb97X, and wb97XD. The effect of the nature and position of substituents on the natural spin density and natural charge is also studied and discussed.

Keywords

• Adiabatic electron affinity (AEA)
• Natural spin densities
• Benzaldehyde
• Density Functional Theory
• ab-initio methods