Theoretical investigation on the triplet excited state properties of the porphyrin-related photosensitizers and the implications in illustrating their photosensitization mechanisms

Application of TD-DFT Theory to Studying Porphyrinoid-Based Photosensitizers for Photodynamic Therapy: A Review

An important focus for innovation in photodynamic therapy (PDT) is theoretical investigations. They employ mostly methods based on Time-Dependent Density Functional Theory (TD-DFT) to study the photochemical properties of photosensitizers. In the current article we review the existing state-of-the-art TD-DFT methods (and beyond) which are employed to study the properties of porphyrinoid-based systems. The review is organized in such a way that each paragraph is devoted to a separate aspect of the PDT mechanism, e.g., correct prediction of the absorption spectra, determination of the singlet-triplet intersystem crossing, and interaction with molecular oxygen. Aspects of the calculation schemes are discussed, such as the choice of the most suitable functional and inclusion of a solvent. Finally, quantitative structure-activity relationship (QSAR) methods used to explore the photochemistry of porphyrinoid-based systems are discussed.

Rigid axially symmetrical C60-BODIPY triplet photosensitizers: effect of bridge length on singlet oxygen generation

Two rigid axially symmetrical C₆₀-BODIPY systems with different bridge lengths have been synthesized and the dyad with short bridge generates a higher quantum yield of singlet oxygen.

TD-DFT calculations of the excited states of metalloporphyrins relevant to organic solar photovoltaic cells

The molecular orbital energies and symmetries, electronic state energies and symmetries, and orbital compositions and oscillator strengths for one-photon radiative transitions up to an energy of 4 eV have been calculated by DFT and TD-DFT methods for 15 d0 and d10 metalloporphyrins. Data for both singlet and triplet excited states are reported and used to identify potential candidates for use as photon upconverters by homomolecular triplet–triplet annihilation.

Microbial efflux systems and inhibitors: approaches to drug discovery and the challenge of clinical implementation

Conventional antimicrobials are increasingly ineffective due to the emergence of multidrug-resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered exploration for novel and unconventional approaches to controlling microbial infections. Multidrug efflux systems (MES) have been a profound obstacle in the successful deployment of antimicrobials. The discovery of small molecule efflux system blockers has been an active and rapidly expanding research discipline. A major theme in this platform involves efflux pump inhibitors (EPIs) from natural sources. The discovery methodologies and the available number of natural EPI-chemotypes are increasing. Advances in our understanding of microbial physiology have shed light on a series of pathways and phenotypes where the role of efflux systems is pivotal. Complementing existing antimicrobial discovery platforms such as photodynamic therapy (PDT) with efflux inhibition is a subject under investigation. This core information is a stepping stone in the challenge of highlighting an effective drug development path for EPIs since the puzzle of clinical implementation remains unsolved. This review summarizes advances in the path of EPI discovery, discusses potential avenues of EPI implementation and development, and underlines the need for highly informative and comprehensive translational approaches.

Effects of a porphyrazine derivative on some developmental characteristics of Drosophila melanogaster

In this study, the effects of a porphyrazine derivative, [octakis (2-trimethylammoniumethyl thio) porphyrazinatocobalt] octaiodide (CoPzq), were explored on the developmental characteristics, sex ratio and egg fertility of Drosophila melanogaster. CoPzq was preferred in the study due to its probability to be used as a chemotherapeutic agent in medicine. As a result of the application of CoPzq, a phenotypic abnormality was revealed within the individuals of F1 and F2 generation of Drosophila. Although individuals of F2 generation did not directly come into contact with the chemical, the rate of abnormality is high. An increase was observed within both generations in terms of the egg fertility. Besides, a deviation emerged in the sex-ratio in some concentrations.