Influence of phenylpropanoid units of lignin and its oxidized derivatives on the stability and βO4 binding properties: DFT and QTAIM approach

Obtaining lignin products is currently one of the great challenges, mainly because of its stable and poorly reactive structure. This work used a DFT and QTAIM approach, seeking to understand the influence of lignin structure on the reactivity and beta O4 binding properties of 18 model structures. The computational modeling used confirmed that lignins derived from more oxygenated monomers have a smaller HOMO-LUMO gap, and therefore are less stable. In the developed study, the replacement of alpha hydroxyl with a carbonyl was able to abruptly change the electron topology, reducing binding energy in beta O4 indicating which SHOX model is more susceptible to breakage.