Quantum Chemical Characterization and Spectral Analysis of Dehydrobenzoannulenes And Antiaromatic Dehydroannulenes

Abstract

Antiaromatic dehydro[12]annulenes ([12]DAs) have interesting but understudied optoelectronic properties that can be applied to linear and nonlinear optics. A density functional theory and Møller-Plesset Perturbation theory study was performed on the [12]DA as well as two derivatives, a dehydrobenzo[12]annulene ([12]DBA) and 1,2,7,8-tetrakis(((tert-butyldimethylsily)oxy)methyl)[12]DA (TBDMS[12]DA), to determine the main electronic transitions contributing to the photoinduced dynamics of each molecule. A comparative study on these electronic excitations revealed similar photoinitiated processes for the [12]DA and [12]DBA in the first excited state that focused electron density on the symmetric cyclic carbon core in lengthening the carbon triple bonds. After spectral analysis and theoretical calculations, the antiaromatic TBDMS[12]DA was found to release its excited population through sequential internal conversion events.