Abstract: Over the last five years, considerable progress has been made with a rational structural modification approach guided by an application of Michl’s perimeter model to TD-DFT calculations carried out with the Gaussian software package. Porphyrin analogues have been prepared with significantly red-shifted and intensified Q bands that are suitable for use as photosensitizer dyes in photodynamic anticancer and antimicrobial therapy. When corrole, chlorin and N-confused porphyrins are formed by introducing a pyrrole-pyrrole bond, a reduced peripheral pyrrole bond and a confused pyrrole nitrogen atom, respectively, there is a significant red shift of the lowest energy Q band into the therapeutic window (620−850 nm) relative to the parent metal porphyrin. The introduction of appropriate meso-substituents, such as thienyl rings, further enhances the red shift of the Q band and facilitates the preparation of gold nanoparticle conjugates. Octabromination at the β-positions also results in a significant red shift due to saddling of the ligand. Novel triarylcorrole, tetraarylchlorin, and N-confused tetraarylporphyrins have been prepared along with their Sn(IV), Ga(III) and/or P(V) complexes. Trans-axial ligation hinders aggregation effects, while the heavy central ion promotes intersystem crossing, resulting in relatively high singlet oxygen quantum yields. The use of molecular modelling to guide the rational design of BODIPY analogues for optical limiting applications will also be described.

Abstract: The particulate methane monooxygenase (pMMO) enzyme, a membrane-bound protein found in methanotrophic bacteria, stands at the forefront of methane to methanol conversion under mild conditions. As the most prevalent natural catalyst for methane oxidation, pMMO offers a promising blueprint for designing novel bioinspired catalysts for selective functionalization of alkanes. Despite its pivotal role, the intricate details of pMMO’s mechanism and active site chemistry remain elusive, primarily due to historical challenges in obtaining precise structural information. This lecture delves into our research group’s computational strategies applied aiming to contribute to the comprehension of pMMO’s reactivity. We highlight the methodological framework guiding our computational approach and showcase significant results illuminating critical aspects of pMMO’s enzymatic function.

Abstract: Perdew and coworkers, in the early 2000s, proposed a hierarchy for DFT functionals, called the Jacob’s Ladder, in analogy to the biblical staircase. In fact, for many properties, the accuracy follows the proposed sequence LSDA < GGA < meta-GGA < hybrid-GGA < double-hybrid-GGA. However, we will show some case studies, particularly for organometallic compounds, where some electronic properties are better described by hybrid functionals and other properties by pure GGA functionals. Since our group is interested in developing new dyes for photodynamic therapy and solar cells, choosing the functional is fundamental in predicting photophysics and photochemistry mechanisms.

Abstract: Combining quantum mechanics (QM) with classical molecular modeling (MM) leads to a powerful tool for studies of non-isolated molecules. This hybrid and multiscale method allows studying molecules in simple and complex environments. This is generally called QM/MM method and it may be used to study the properties, spectroscopy and reactivity of molecules in solution, as well as molecules in more complex environments such as critical fluids, proteins and even the vicinities of a critical point. A brief review of the methodology developed in our laboratory, the sequential QM/MM, using either Monte Carlo or Molecular Dynamics will be presented and a variety of applications of molecular properties and UV-Vis spectroscopy will be shown in different environments, such as simple homogeneous liquids, supercritical fluids and protein environment.