A novel approach to the preparation of stable Pd-substituted verdazyls was developed through the direct oxidative addition of iodoverdazyls to Pd(PPh3)4.

Iodine‐ and ethynyl‐containing 'Kuhn'‐verdazyls, oxoverdazyls, and nitronyl nitroxides were investigated as building blocks for the preparation of multi‐spin systems via the Sonogashira reaction, and, as a result, eleven diradicals were prepared with fair yields. The reactivity of the building blocks indicates that oxoverdazyl iodides are effective starting components for the synthesis of diradicals via the Sonogashira coupling. The described one‐step protocol allows combining different spin units, thereby facilitating the design of tolane‐bridged diradicals and screening of their properties. The novel compounds were characterized by cyclic voltammetry, UV/Vis and electron spin resonance (ESR) spectroscopy. Although the electrochemical investigation and electronic spectra showed a negligible influence of radical moieties on each other, ESR data revealed a strong exchange interaction between two unpaired electrons. The prepared verdazyl‐nitronylnitroxide diradicals have high stability at storage and hold promise for further investigation and application.

The local surface plasmon resonances of gold nanoparticles have the potential to create alternative pathways for organic chemical reactions. These transformations depend on various physical factors, such as the temperature, illumination regime, and nanoparticle type. However, the role of chemical factors associated with organic reactants, including the molecular structure, electronic effects, and bonding with the metal surface, is often underestimated. To explore the role of these chemical factors, we synthesized five alkoxyamines (AAs) with different chemical and electronic structures and used electron paramagnetic resonance spectroscopy to study the kinetics of plasmon-induced homolysis. The kinetic data revealed that the rate constant (k d) for plasmon-assisted homolysis is dependent on the highest occupied molecular orbital (HOMO) energy of the AAs, which cannot be described by the kinetic parameters or activation energies observed in thermal homolysis experiments. The proximity of the HOMO to the Fermi energy (E f) of Au led to a more active decrease in the energy required to excite the adsorbate. The observed trend in k d indicates that the intramolecular excitation mechanism plays a key role instead of other commonly accepted mechanisms, which is supported by DFT calculations, spectroscopic characterization, and numerous control experiments. The intramolecular excitation mechanism is the most relevant explanation for the plasmon-induced homolysis of AAs. This observation suggests that the electronic structures of the organic molecules may play a key role in other related reactions used to study the mechanisms of plasmon catalysis.

The generation of verdazyl radicals under heating or irradiation have been highlighted.

Two alkylated verdazyl radicals (AlkVZs) were investigated as active compounds for photoinitiated controlled MCF-7 cell death. Observed results unambiguously showed that AlkVZ could be a potential structural moiety for the design of a novel family of photodynamic therapy agents. The main advantage of the proposed substances is an oxygen-independent generation of active radicals, which play a pivotal role in the treatment of oxygen-deficient tumors.

The excitation of localized plasmon resonance on nanoparticles followed by the interaction with organic molecules leads to new pathways of chemical reactions. Although a number of physical factors (temperature, illumination regime, type of nanoparticles, etc.) are affecting this process, the role of the chemical factors is underestimated. Challenging this assumption, here we studied the kinetic of plasmoninduced homolysis of five alkoxyamines (AAs) with different chemical and electronic structures using electron paramagnetic resonance (EPR). The kinetic data revealed the dependence of plasmonic homolysis rate constant (kd) with the HOMO energy of AAs, which cannot be described by the kinetic parameters derived from thermal homolysis experiments. The observed trend in kd allowed to suggest the key role of intramolecular excitation mechanism supported by the TDFDT calculations, additional spectroscopic characterization, and control experiments. Our work sheds light on the role of the electronic structure of organic molecules in plasmonic chemistry.

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The development of novel photo‐dynamic therapy (PDT) agents enabling to treat the oxygen‐deficient tumors is the emerging tasks for the modern medicinal chemistry. Herein, we describe the design and preparation of water‐soluble agents for PDT which generate active radical species upon light irradiation. Two conjugates of carbohydrates with 1,2,4,6‐substituted‐1,4‐dihydro‐1,2,4,5‐tetrazin‐3(2H)‐ones (AlkVZs) demonstrated high oxygen‐independent cytotoxicity on PC‐3 and Jurkat cancer cells under light irradiation combining with low toxicity in the dark. The efficacy of prepared compounds was estimated using MTT and Alamar Blue tests as well as microscopic dead/live colored images and flow cytometry. The analysis of obtained results reveals the influence of sugar moiety on the activity of AlkVZs. We believe that obtained compounds have high potency as platform for design of new agents for photo‐dynamic therapy.