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.

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The N–N bond structure of the key intermediate in the reported catalytic ammonia production (Nature 2019, 568, 536–540) should be described as containing a N–N double bond, instead of containing a N–N triple bond. Two 3c-delocalized bonds are found in this fragment. The analysis of the oxidation states reveal that the N reduction is achieved mainly during the step of N–N bond cleavage; SmI2-ROH reduction steps reduce Mo atoms and add protons to N atoms without changing their oxidation states. The catalytic cycle is thermodynamically investigated using the DFT method, revealing that the rate-determining step is the reductive formation of the first N–H bond and the nitrogen reduction occurs mainly in the N–N cleavage step. In addition, linear relationships between vibrational stretching frequencies, effective nuclear charges (Z*), and bond dissociation energy (E 0) of a Mo–N bond are also developed.