Facile approach to the functionalization of exocyclic nitrogen atom of 1,3-dialkyltetrazolium-5-aminides by benzoyl chloride, acetic anhydride, p-toluenesulfonyl chloride, methanesulfonyl chloride and phenyl isothiocyanate was developed. Functionalization was carried out at room temperature under Schotten-Baumann reaction conditions in biphasic system (diethyl ether–aqueous sodium hydroxide). Corresponding N-acyl-, N-sulfonyl- and N-(N′-phenylthiocarbamoyl)-1,3-dialkyltetrazolium-5-aminides were obtained in high yields (62–97%) and identified using 1H and 13C NMR, LC–MS, IR spectroscopy. X-ray diffraction investigation confirmed the structures of N-acetyl- and N-methylsulfonyl-1,3-di-tert-butyltetrazolium-5-aminides, and N-p-toluylsulfonyl-3-tert-butyl-1-methyltetrazolium-5-aminide prepared.

Cyclometalated platinum(II) complexes exhibit opposite luminescent responses to different π-hole donors. While perfluoroarenes enhance phosphorescence through weak interactions, perfluoroquinones completely quench emission despite forming structurally similar cocrystals. X-ray crystallography shows that quinone adducts exhibit shorter Pt···centroid distances (3.382-3.412 vs 3.624-3.721 Å for perfluoroarenes) and multiple C···Pt tetrel bonds. Unlike yellow-green luminescent perfluoroarene systems, quinone adducts display characteristic brown coloration and new charge-transfer absorption bands at 575-578 nm. DFT calculations reveal that dz2(Pt) → π*(quinone) orbital interactions contribute -6.8 kcal/mol (32% of orbital binding energy), creating efficient nonradiative deactivation pathways absent in perfluoroarene systems. Natural transition orbital analysis confirms intermolecular charge transfer in quinone adducts versus localized excitations in arene systems, explaining the complete luminescence quenching despite structural similarities. This work establishes perfluoroquinones as a new class of luminescence modulators, demonstrating that electronic coupling strength determines whether π-hole interactions enhance or quench phosphorescence.

The rare example of a study of complexation of mesoionic tetrazoles is reported. Reaction of N-benzoyl-1,3-di-tert-butyltetrazolium-5-aminide with CuCl2 was investigated and two different complexes were obtained depending on reaction conditions. Mixed-ligand complex [CuCl(N-benzoyl-1,3-di-tert-butyltetrazolium-5-ami-nide)(N-(1-(tert-butyl)-1H-tetrazol-5-yl)benzimidate)] was obtained at room temperature, whereas [Cu(N-(1-(tert-butyl)-1H-tetrazol-5-yl)benzimidate))2] was prepared under reflux of the reaction mixture in toluene. The observed transformation of intial aminide presents the first example of N-dealkylation of tetrazoles under complexation. Synthesized compounds were identified by single crystal X-ray analysis, UV-Vis, NMR, IRspectroscopy and thermal analysis. Both obtained coordination compounds present mononuclear molecular complexes with chelating ligands coordinated to the metal via the exocyclic O atom and the tetrazole ring N4 atom.

The clinical efficacy of first-line oxaliplatin-based treatments in metastatic colorectal cancer (CRC) is universally limited by acquired resistance, a process driven by metabolic plasticity that allows tumors to dynamically reprogram their energy metabolism for survival. To exploit this vulnerability, we developed a novel organometallic scaffold based on palladium(II) complexes bearing acyclic diaminocarbene ligands. The complexes exhibit potent, low-micromolar antiproliferative activity against glycolytic CRC models and, crucially, display undiminished efficacy against oxaliplatin-resistant cells. We establish that their antiproliferative action hinges on the formation of stable H-bonded lipophilic cations under physiological conditions, which selectively target mitochondria of metabolically dysregulated cancer cells. This triggers a critical surge in mitochondrial lipid peroxidation, culminating in a regulated cell death that adapts to the cellular context, manifesting as either apoptosis or non-apoptotic death depending on the metabolic and redox status of the tumor cell.

The effect of deposited aggregated Co–CoO nanoparticles with an average diameter of 160 nm on the concentration of charge carriers and mechanisms of their transport in Co–CoO/graphene/SiO2 hybrid structures is studied. The structures are obtained by electrochemical deposition of cobalt nanoparticles on the surface of single-layer CVD graphene in the reversible galvanostatic mode from an electrolyte containing a mixture of CoSO4∙6H2O (1.25 g/L) and NaCl (0.064 g/L) at a cathode current density of 2.5 mA/cm2 and an anodic current density of 1.25 mA/cm2. It is shown that the deposition of Co–CoO nanoparticles leads to an almost twofold decrease in the conductivity of the structure. We attribute this effect to the exclusion of some of the intrinsic defects of graphene in the studied structure from the carrier transport process. The coexistence of quantum correction (QC) mechanisms to the Drude conductivity under weak localization conditions and conventional band (activation-like) conductivity was discovered. The QC dominance in conductivity both before and after deposition of Co–CoO particles, as well as a decrease in the value of the pre-exponential factor σa0 after deposition of the particles, included in the activation mechanism, from 2.8 × 10–4 to 3.1 × 10–5 S.

ABSTRACTTo understand the nature of heterogeneous catalytic processes and improve their efficiency, it is necessary to conduct both experimental and theoretical studies. At the same time, there is no unified approach to obtaining the necessary data using quantum chemistry methods. In this work, problems of the existing calculational approaches are analyzed. The obtained information is used to develop the original three‐layer embedded cluster model approach, which is shown to be the most effective. The general algorithm for obtaining such models for various oxides is formulated. The sufficient accuracy of the proposed models in predicting geometric and energy characteristics, vibrational frequencies, activation barriers, and thermodynamic characteristics is verified. The specifics of calculating the thermodynamic characteristics of heterogeneous processes using the proposed cluster models is studied in detail. The developed approach is an effective tool for studying the mechanism of heterogeneous catalytic processes both by itself and in combination with experiment.

Invited for the cover of this issue are Tatiyana Serebryanskaya, Mikhail Kinzhalov and co-workers at St. Petersburg State University, the Research Institute for Physical Chemical Problems, Belarusian State University, Togliatti State University and Blokhin National Medical Research Center of Oncology. The image depicts the shield of Pallas Athena with the structure of a palladium carbene complex that protects against triple-negative breast cancer. Read the full text of the article at 10.1002/chem.202400101.

С использованием реакций полимераналогичных превращений полиакрилонитрила синтезированы соли поли-5-винил-N,N′-диметилтетразолия – первые представители ионных карбоцепных полимеров с кватернизованным положительно заряженным тетразольным циклом в боковой цепи. Синтез солей включает в себя реакцию циклоприсоединения азида натрия к полиакрилонитрилу с образованием поли-5-винилтетразола, исчерпывающее алкилирование которого диметилсульфатом приводит к образованию метилсульфата поли-5-винил-N,N′-диметилтетразолия. В результате обработки последнего водными растворами тетрафторборной или хлорной кислот получены тетрафтороборат и перхлорат поли-5-винил-N,N′-диметилтетразолия соответственно. Показана высокая эффективность использования синтезированных полимеров для селективного извлечения палладия из модельных систем, содержащих ионы других тяжелых и переходных металлов.

The transition points in hexamethylphosphoramide are theoretically studied for a series of acid-base indicators. Three new indicators with multiple transition points and deeply colored low-nucleophilic anions are designed. A general basicity scale is established for highly basic hexamethylphosphoramide solutions, expanding beyond the basicity of the strongest currently known molecular bases.

Theoretical design of molecular superbases has been attracting researchers for more than twenty years. General approaches were developed to make the bases potentially stronger, but less attention was paid to the stability of the predicted structures. Hence, only a small fraction of the theoretical research has led to positive experimental results. Possible stability issues of extremely strong bases are extensively studied in this work using quantum chemical calculations on a high level of theory. Several step-by-step design examples are discussed in detail, and general recommendations are given to avoid the most common stability problems. New potentially stable structures are theoretically studied to demonstrate the future prospects of molecular superbases design.

The approaches to estimating the changes in enthalpy, entropy, and Gibbs energy of adsorption processes and heterogeneous catalytic reactions on the basis of the quantum chemical calculation data were studied. By comparing with the experimental data on CO adsorption on the anatase (TiO2) surface, the applicability of the developed multilayer cluster model for calculation of the adsorption energy (enthalpy) was shown. The data on the calculation methods of the entropy change in heterogeneous processes were analyzed. The use of the theories of an ideal two-dimensional gas and an ideal two-dimensional lattice gas for estimating a configuration contribution to the entropy of a heterogeneous process was studied. The density of adsorption centers on the (101) anatase surface and the population corresponding to the standard state of an ideal two-dimensional gas were calculated. The consistency of the studied models at low populations was shown, and the limits of their applicability were established.

The possibility of theoretical calculation of the ionization constants of strong organic bases in dimethyl sulfoxide and hexametapole was studied by the DLPNO-CCSD (T) and DFT methods. By comparison with the experimental data available in the literature, it has been established that the error of such calculations lies within 1–2 pKa units. The stability of some ionizing solvents against strong organic bases is investigated, the mechanisms of decomposition of solvent molecules in strongly basic media are predicted, and the corresponding energy barriers are estimated. According to the calculations, among ionizing solvents, hexamethylphosphoramide has the highest resistance to superbases, being able to maintain pH > 50 at room temperature. At the same time, 1,3-dimethyl-2-imidazolidinone gradually decomposes under these conditions, while tetrahydrofuran and pivalonitrile are even less stable.

1-R-Tetrazoles (R = Et, i-Pr, t-Bu) were found to react with copper(II) tetrafluoroborate hexahydrate and cop-per(II) nitrate tetrahydrate giving the complexes [Cu2L8(H2O)(2)]X-4, where L = 1-R-tetrazole, X = BF4 or NO3. Single crystal X-ray analysis showed that the complexes comprised dinuclear cations [Cu2L8(H2O)(2)](4+), with six tetrazole ligands showing monodentate N4-coordination, and two ones providing N-3,N-4 bridges between the copper(II) cations; water molecules complete the distorted octahedral coordination of metal ions. Magnetic susceptibility measurements revealed that the copper(II) ions were very weakly antiferromagnetically coupled. Complex [Cu2L8(H2O)(2)](BF4)(4) (L = 1-isopropyltetrazole) was found to exhibit a temperature induced reversible single-crystal to single-crystal polymorphic phase transition. For this complex, adiabatic calorimetry was used to find the standard thermodynamic characteristics of this transition as well as the standard thermodynamic func-tions of the compound in the temperature range of 80-370 K. Additionally, mononuclear complex of the composition [CuL6](BF4)(2) (L = 1-ethyltetrazole) was obtained during the investigation and structurally characterized.

NO catalytic reduction on Ag/gamma-Al2O3 catalysts is a very promising process from the industrial and ecological perspective. Details of its mechanism, which are still not fully clear, have great importance for a deep understanding of various heterogeneous NO reduction processes. In this work, a thorough theoretical study of the mechanism of NO reduction on the Ag/gamma-Al2O3 catalyst is carried out. Two schemes of the mechanism for catalysts with different silver concentrations and, subsequently, with different reaction centers, are proposed. For the catalyst with a low silver content, a mechanism based on isocyanate species is proposed, while for catalysts with a high silver content, key intermediates are adsorbed NO dimers. The thermody-namic and kinetic feasibility of the proposed schemes is confirmed by density functional theory calculations of the reaction pathways both on isolated silver clusters and on the catalyst surface. These schemes explain the experimentally observed N2O or N2 prevalence in the reaction products. Calculations of the catalyst surface are carried out within the original three-layer embedded cluster model, which provides accurate results of calculations of vibrational frequencies, geometries, and energy characteristics. The process of silver particle migration along the catalyst surface is studied. Energy barriers of migration are estimated. The influence of the catalytic center nature and presence of the aluminum oxide support on NO, N2, and N2O adsorption processes are studied, and the corresponding adsorption energies are calculated.

The functionalization of (R,R)-S,S'-di-tert-butylferrocene-1,1'-disulfoxide by deprotolithiation-electrophilic trapping sequences was studied towards polysubstituted, enantiopure derivatives for which the properties were determined. While the 2,2'-disubstituted ferrocene derivatives were obtained as expected, subsequent functionalization of the 2,2'-di(phenylthio) and 2,2'-bis(trimethylsilyl) derivatives occurred primarily at the 4- or 4,4'-positions. This unusual regioselectivity was discussed in detail in light of pKa values and structural data. The less sterically hindered 2,2'-difluorinated derivative yielded the expected 1,1',2,2',3,3'-hexasubstituted ferrocenes by the deprotometallation-trapping sequence. Further functionalization proved possible, leading to early examples of 1,1',2,2',3,3',4,4'-octa, nona and even decasubstituted ferrocenes. Some of the newly prepared ferrocene-1,1'-disulfoxides were tested as ligands for enantioselective catalysis and their electrochemical properties were investigated.

Based on both total energy calculations and comparison of experimental and calculated characteristics of the photoelectron spectrum (PHES), the structural assignment of clusters A(gn)(-) (n = 13-16) and Cu-m(-) (m = 14-17) has been made using the density functional theory (DFT) model with our previously developed S2LYP functional. A comparative study of size dependence of geometry, electronic structure, and physicochemical properties has been carried out for a series of anionic silver and copper clusters containing up to 20 atoms. For the cases when two isomers contribute to the experimental PHES, the isomerization barriers and molar ratio of isomers were estimated. It has been shown that the geometry and the properties that are determined mainly by ns-derived electronic states are similar for copper and silver clusters. However, due to the larger contribution of (n-1)d-electrons to the chemical bond, the potential energy surface of copper clusters is less smooth, and these clusters are characterized by higher isomerization energies compared to silver clusters. The isomerization energies of clusters and the number of isomers with similar energies increase with enlarging cluster size. Thus, clusters containing less than 20 atoms easily overcome the barriers of intramolecular isomerization (i.e., behave like liquids). However, it is expected that cooled clusters containing several tens of atoms will have a rigid geometry due to high intramolecular isomerization energies.

Drawing the experience of 5-phenyl- and 5-pyridyltetrazoles, it was shown that classical nitration-reduction methods in combination with typical alkylation reactions of tetrazole derivatives can be used to obtain multitopic polynuclear tetrazole-containing ligands. Methods for the preparation of a number of previously undescribed polynuclear tetrazole derivatives, including those combining both tetrazole and pyridine rings in the molecule, have been developed. The composition and structure of the obtained compounds were determined by elemental analysis, single crystal X-ray diffraction, NMR and IR spectroscopy. For (5-(pyridin-2-yl)tetrazol-2-yl)(5-(pyridin-2-yl)tetrazol-1-yl)methane the crystalline structure was determined and it was found that this compound forms a 3D polymer framework due to non-classical hydrogen bonds. In its crystal structure there is a network of π – π stacking interactions between tetrazole rings of neighbouring molecules, as well as between pyridine rings.

Novel tripodal ligands (R1N4CS)3CH, where R1 = Me, Ph, were synthesised by alkylation of 1-R-tetrazol-5-thioles with iodoform in alkaline media. These ligands were identified based on data of elemental analysis, nuclear magnetic resonance spectroscopy, thermal analysis, and X-ray diffraction analysis of single crystals.

The purpose of the study is to design synthetic methodologies, especially directed deprotometalation using polar organometallic reagents, to access polysubstituted ferrocenesulfoxides. From enantiopure 2-substituted (SiMe3, PPh2) S-tert-butylferrocenesulfoxides, a third substituent was first introduced at the 5 position (SiMe3, I, D, C(OH)Ph2, Me, PPh2, CH2NMe2, F) and removal of the trimethylsilyl group then afforded 2-substituted ferrocenesulfoxides unreachable otherwise. Attempts to apply the “halogen dance” reaction to the ferrocenesulfoxide series led to unexpected results although rationalized in light of calculated pKa values. Further functionalizations were also possible. Thus, new enantiopure, planar chiral di- and trisubstituted ferrocenes have been obtained, in addition to several original 2-substituted, 2,3- and 2,5-disubstituted, 2,3,5-trisubstituted and even 2,3,4,5-tetrasubstituted ferrocenesulfoxides, also enantiopure.

Complexes [MII(2-pytz)Cl2] (M(II) = Pt, Pd; 2-pytz = 2-(tetrazol-1-yl)pyridine) were synthesised via direct interaction of the corresponding metal chlorides (K2PtCl4 or PdCl2) with 2-pytz under ambient conditions. RuCl3 does not react with 2-pytz under reflux in the protic media, while under reflux in N, N-dimethylformamide in the presence of LiCl, decomposition of the tetrazole cycle occurred leading to the formation of Ru(III)-coordinated N, N-dimethyl-N ′-(pyridin-2-yl)formimidamide derivative Li[RuIII(Py — N =C — NMe2)2Cl2]. The complex [Ru(2-pytz)(DMSO)3Cl2] ⋅ MeOH, where DMSO is dimethyl sulfoxide, was synthesised by reacting a specially prepared precursor cis-[Ru(DMSO)4Cl2] with 2-pytz in methanol under reflux conditions. The complex [Ru(2-pytz)(DMSO)2Cl2] was synthesised by reacting cis-[Ru(DMSO)4Cl2] with 2-pytz in ethanol under reflux conditions. The resulting complexes were characterised by elemental analyses, electrospray ionisation mass-spectrometry with detection of positive and negative ions, infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, and simultaneous thermal analysis. The structures of complexes [Pd(2-pytz)Cl2] and [Ru(2-pytz)(DMSO)3Cl2] ⋅ MeOH were investigated by single-crystal X-ray analysis. In the former, 2-pytz shows a N,N-chelating coordination via the pyridine ring N and the tetrazole ring N2 atoms. In the latter, 2-pytz coordinates as a monodentate ligand via the tetrazole ring N4 atom. According to 1H NMR spectroscopy data, in complex [Ru(2-pytz)(DMSO)2Cl2], 2-pytz coordinates as a N, N-chelating ligand via the pyridine ring N and the tetrazole ring N2 atoms.