Computational Study of Photochemical Relaxation Pathways of Platinum(II) Complexes

Abstract

A series of functional platinum­(II) complexes (Pt1–Pt3), which present high activity in four-photon absorption, in vivo imaging, and precise cancer therapy, as previously reported by the experimental work of Zhang et al. (Inorg. Chem. 2021, 60, 2362–2371), are computationally investigated in the article. We find that after the complex goes through four-photon absorption to the S1 state, it undergoes intersystem crossing to the T2 state and eventually reaches the T1 state through internal conversion. On the T1 state, both radiative and nonradiative decay to S0 exit. The radiative decay forms the basis for the phosphorescence imaging in tissues as reported in the original paper. In addition, the nonradiative decay can simultaneously generate cytotoxic singlet oxygen by the excited energy transfer process, also known as triplet oxygen’s quenching of triplet states. We conclude that the phosphorescence property as well as the photosensitizer character jointly bring high activity of in vivo imaging and photodynamic therapy to these complexes.

Structural confirmation of synthetic cannabinoids in seized electronic cigarette oil: A combined mass spectrometric and computational study

“…Therefore, ketone α ‐cleavage pathway was available for the electronic state reached by vertical ionization process, giving 5F5 and 5F6 as intermediates. Although from the perspective of energy pathways forming 5F1 + 5F2 and 5F8 + 5F9 were lower in Gibbs free energy increase, they were state‐forbidden since no obvious EDD distribution existed on the corresponding bonds, which required state‐switch to reach their products and was a dynamical disadvantage 27 …”

“…Although from the perspective of energy pathways forming 5F1 + 5F2 and 5F8 + 5F9 were lower in Gibbs free energy increase, they were state-forbidden since no obvious EDD distribution existed on the corresponding bonds, which required state-switch to reach their products and was a dynamical disadvantage. 27 Nevertheless, in ESI mechanism, proton transfer (PT) was the main driving force and could also be assisted by solvent-mediated PT or solvent polarized field. It has also been pointed out by many theoretical works that a tunneling effect must be taken into consideration in discussion of PT dynamics.…”

Computational study of the photophysical properties and electronic structure of iridium(iii) photosensitizer complexes with electron-withdrawing groups

“…The Huang–Rhys factors could measure how easily the non-radiative processes like IC occur. 4 Here, Huang–Rhys factor diagrams were applied to assist in reflecting non-radiative processes from the T 2 to T 1 state of Ir1 and Ir2 (see Fig. 5).…”

“…1 Efficient photosensitizers are not only used for photocatalysis, 2,3 but also for dye-sensitized solar cells (DSSCs) and photodynamic therapy (PDT). [4][5][6] For photosensitizers, good performance requires various photophysical characteristics, including strong visible light absorption and long lifetimes of the excited states. Unfortunately, relatively strong radiative and non-radiative processes, including phosphorescence emission and reverse intersystem crossing (rISC) can result in short excited state lifetimes.…”

Enhanced luminescence properties through heavy ancillary ligands in [Pt(C^N^C)(L)] complexes, L = AsPh3 and SbPh3

“…UV-bands in both systems have been previously assigned to transitions into LC (π–π*) states, whereas mixed LC/metal-to-ligand charge transfer (MLCT) states were discussed for increasingly long-wavelength bands. 31,51,69,70…”