Complexation Research Articles

Problems of Transport Provision in the Regions of Eastern Siberia and the Far East

The article provides a detailed analysis of the existing transport infrastructure in the East of the country, taking into account the development of export directions. A comprehensive study of two main railways, highways and ports that provide communication in the regions of Eastern Siberia and the Far East was carried out. The advantages, disadvantages and prospects for the development of the largest checkpoints have been identified. It is shown that there is an annual development and strengthening of the international integration of the eastern regions of Russia with the countries of the Asia-Pacific region, while taking into account the national interest of the Russian state. The integration of the eastern regions with the unified transport system of Russia is also developing by increasing the carrying capacity of the Eastern range. The number of border road and rail crossings is growing, port capacities are expanding, and the country’s key logistics hub is being formed. But despite this, it is shown that there are transport problems in the Far Eastern regions of the country: lack of supply railways to seaports, low railway capacity, poor development of transport infrastructure for the development of natural resources. It is concluded that there is a need to develop transport infrastructure in the Far East, which will improve socio-economic indicators in the eastern regions. The development of integration of the railway with sea ports will increase the export of raw materials and products with high added value from the mining and metallurgical, fuel and energy, chemical and agro-industrial complexes. Effective implementation of transit potential will not only make it possible to obtain economic benefits from participation in international transport, but will also create new instruments for Russia’s influence on global economic processes.

Anaerobic Catalyst Design for Alcohol Oxidation: Fine‐Tuning Copper/TEMPO with Bipyridine Proportions

In this study, we investigate the indirect electro‐oxidation of benzyl alcohol using the Copper/TEMPO catalytic system, which combines copper complexes with 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO) in an anaerobic medium. We reexamine the impact of bpy ligand proportions, exploring ratios of 1:1, 2:1, 3:1, and 4:1 on catalytic activity. Cyclic voltammetry and visible spectroscopy reveal distinct electrochemical characteristics and complex formations at different bpy ratios. Simulations uncover intricate energy equilibria involving ion coordination, varying with oxidation state and bpy proportion. Theoretical and experimental spectra align, supporting the proposed structures. The Brønsted base, triethylamine (TEA), essential in this anaerobic system, shows different voltammetric profiles with each ligand ratio, revealing key interactions with bpy complexes. In the presence of benzyl alcohol, the 1:1 and 2:1 ratios exhibit indirect catalytic activity, with the 2:1 ratio yielding significantly higher current densities. This establishes a new optimal condition where [Cu(bpy)₂]²⁺ formed in a 2:1 stoichiometry demonstrates superior activity with a lower redox potential, while maintaining labile coordination points for necessary interactions. Theoretical results also indicate weaker TEMPO coordination to [Cu(bpy)₂]²⁺.

Recent Catalytic Routes to 3-Azabicyclo[3.1.0]hexane Derivatives

The review summarizes recent achievements in the synthesis of 3-azabicyclo[3.1.0]hexanes (3-ABH). These heterocyclic systems are ubiquitous in the structure of molecules that can act on a variety of biological targets and are actively used in drug design. Classification and analysis of the modern approaches to 3-ABHs based on the use of transition metal complexes are carried out, and the mechanisms of the key processes are considered. The presented reactions include the assembly of 3-ABH by annulation of three- or five-membered rings as well as numerous one-step syntheses from acyclic precursors via tandem cyclizations.

Development of the Cluster Chemistry, Supramolecular Chemistry and Chemistry of Metal-Organic Frameworks by Professor Vladimir P. Fedin and His School

The article briefly summarizes the main scientific directions contributed to and developed by the outstanding scientist—a leader in the field of coordination chemistry, cluster chemistry, supramolecular chemistry and chemistry of metal-organic coordination polymers, Corresponding Member of the Russian Academy of Sciences Vladimir Petrovich Fedin.

DFT Study of Coordination of N-Monochlorosubstituation Derivatives of Biguanide

Biguanides [HN=C(NR1R2)-NH-C(NR3R4)=NH] constitute an important family of molecules used as drugs in the treatment of diabetes. It is known that some transition metal complexes with given organic compounds deeply increase both therapeutic actions of the metal and the organic compound. The chlorine atom, a preferred substitute in pharmacy, improves the effectiveness of drugs and reduces their side effects. The mesmeric +M effect of the chlorine atom would make it possible to enhance the nucleophilic character of any N-chlorosubstituted nitrogen. In this work a theoretical study of coordination of N-chlorine derivatives of biguanide is carried out mainly at the DFT/B3LYP/6-31G (d, p) level. The Gaussian 09 & 03, HyperChem softwares and the DCENT-QSAR program are used. The coordinating possibility of each ligand were studied analyzing some coordinating indicators as: interatomic bond lengths, atomic charges, molecular electrostatic potentials, frontier orbital structures and electrophilic superdelocalizability. Then, the formation of its complex with zinc (II) has been calculated. The results of the calculations revealed the imine nitrogen atoms as the most favorable coordination sites. Bioactive complexes of these ligands with Zn (II) are modelled. Testing the bioavailability of obtained complexes according to the Lipinski rules of 5, we noticed that they can be considered as drug-candidates.

Synthesis, characterization and biological study of 2-acetylbenzothiophene 4-cyclohexyl-3-thiosemicarbazone ligand and its transition metal complexes

Synthesis, characterization and biological study of 2-acetylbenzothiophene 4-cyclohexyl-3-thiosemicarbazone ligand and its transition metal complexes

Theoretical investigation of structure and electronic properties in Cisplatin-citrate complexes.

Cisplatin (CDDP) is an effective Platinum (Pt) based anticancer drug used in chemotherapy. However, its effectiveness is limited due to its instability in solvents, along with the side effects it causes due to DNA damage. Nanoparticles (NPs) were developed in vitro to address these issues by loading CDDP into various types of NPs, including metal, lipid, and biological NPs. Citrate was employed as a biocompatible compound in nanomedicine to reduce cytotoxicity and enhance stability. In our study, the physicochemical and electronic properties of CDDP and citrate have been investigated using density functional theory (DFT), with a comparison of their behavior in water and DMSO. Additionally, TD-DFT was applied to analyze the UV-Vis spectra results. Six complexes have been proposed to better understand the interaction between citrate and CDDP. The results demonstrated that the CDDP could form stable complexes with citrate in both water and DMSO, and the considered complexes exhibited UV-Vis spectra within the experiment range. The frontier orbitals, electron densities mapping, and electrostatic potential analysis revealed that complex 5, where citrate di-substituted on two chlorides, is the most likely and effective complex. In summary, our investigation sheds light on the potential of CDDP-citrate complexes to address the limitations of CDDP, offering insights into their stability and interaction in solvents and highlighting the promising efficacy of specific complex formations for future therapeutic applications.

Engineering Corrole and Porphyrin-Based Multivariate Metal-Organic Frameworks for Si-H Bond Insertion.

As a contracted porphyrin analogue, corrole shows a more acidic and trinegative/triprotic nature compared with porphyrin in the field of coordination chemistry. However, the direct introduction of corrole into a metal-organic framework is quite difficult due to its lower C2V symmetry. Herein, we report the one-pot synthesis of a series of corrole and porphyrin-based multivariate porphyrinic metal-organic frameworks M1(TCPC)@M2-PCN-222 (M1 = CuIII, MnIII, FeIVCl; TCPC = 5,10,15-tris(4-carboxyphenyl) corrole; M2 = CoII, CuII, NiII, FeIIICl) and applied them to the insertion of a Si-H bond with α-diazoacetates. The resultant FeCl(TCPC)@Ni-PCN-222 displayed the highest efficiency with a turnover number of 796 based on the amount of Fe, which could be reused at least 5 times without a negligible loss of activity. Mechanistic studies disclosed that the reactivity of FeCl(TCPC)@Ni-PCN-222 came from the synergistic effect between FeCl(TCPC) and Ni-PCN-222, in which FeCl(TCPC) acted as the active site in the formation of metal-carbene, whereas Ni-PCN-222 helped condense the silane molecules for boosting the insertion of the Si-H bond.

Coordinative Self‐assembly of π‐Electron Magnetic Porphyrins

π‐Electron magnetic compounds on surfaces have emerged as a powerful platform to interrogate spin interactions at the atomic scale, with great potential in spintronics and quantum technologies. A key challenge is organizing these compounds over large length scales, while elucidating their resulting magnetic properties. Herein, we offer a relevant contribution toward this objective, which consists of using on‐surface synthesis coupled with coordination chemistry to promote the self‐assembly of π‐electron magnetic porphyrin species. A porphyrin precursor equipped with carbonitrile moieties in a trans arrangement was prepared by solution synthesis and deposited on a Au(111)/mica. Depending on the specific growth protocol, surface‐promoted reactions led to the transformation of the precursor into non‐magnetic Au‐CN coordinated porphyrin monomers, covalent porphyrin dimers, and one‐dimensional porphyrin polymers (based on porphyrin monomers or covalent porphyrin dimers), as revealed by scanning probe microscopy studies combined with theoretical calculations. Interestingly, the scanning tunneling microscopy tip could convert such closed‐shell porphyrin units into open‐shell species by the removal of some peripheral hydrogen atoms. The magnetic features (i.e., singlet or triplet ground state) of the porphyrin units comprising the polymers were investigated for polymers of different lengths. No magnetic exchange coupling between adjacent units was observed.

Nitrogen-Rich Conjugated Macrocycles: Synthesis, Conductivity, and Application in Electrochemical CO2 Capture.

Here we report a series of nitrogen-rich conjugated macrocycles that mimic the structure and function of semiconducting 2D metal-organic and covalent organic frameworks while providing greater solution processability and surface tunability. Using a new tetraaminotriphenylene building block that is compatible with both coordination chemistry and dynamic covalent chemistry reactions, we have synthesized two distinct macrocyclic cores containing Ni-N and phenazine-based linkages, respectively. The fully conjugated macrocycle cores support strong interlayer stacking and accessible nanochannels. For the metal-organic macrocycles, good out-of-plane charge transport is preserved, with pressed pellet conductivities of 10-3 S/cm for the nickel variants. Finally, using electrochemically mediated CO2 capture as an example, we illustrate how colloidal phenazine-based organic macrocycles improve electrical contact and active site electrochemical accessibility relative to bulk covalent organic framework powders. Together, these results highlight how simple macrocycles can enable new synthetic directions as well as new applications by combining the properties of crystalline porous frameworks, the processability of nanomaterials, and the precision of molecular synthesis.

Local Wave Function Embedding: Correlation Regions in PNO-LCCSD(T)-F12 Calculations.

Many chemical reactions affect only a rather small number of bonds, leaving the largest part of the chemical and geometrical structure of the molecules nearly unchanged. In this work we extended the previously proposed region method [J. Chem. Phys. 128, 144106 (2008)] to PNO-LCCSD(T)-F12. Using this method, we investigate whether accurate reaction energies for larger systems can be obtained by correlating only the electrons in a region of localized molecular orbitals close to the reaction center at high-level (PNO-LCCSD(T)-F12). The remainder is either treated at lower level (PNO-LMP2-F12) or left uncorrelated (Hartree-Fock frozen core). It is demonstrated that indeed the computed reaction energies converge rather quickly with the size of the correlation regions toward the results of the full calculations. Typically, 2-3 bonds from the reacting atoms need to be included to reproduce the results of the full calculations to within ±0.2 kcal/mol. We also computed spin-state energy differences in a large transition metal complex, where a factor of 15 in computation time could be saved, still yielding a result that is within ±0.1 kcal/mol of the one obtained in a full PNO-LCCSD(T)-F12 calculation.

Artificial Gold Enzymes Using a Genetically Encoded Thiophenol‐Based Noble‐Metal‐Binding Ligand

Incorporating noble metals in artificial metalloenzymes (ArMs) is challenging due to the lack of suitable soft coordinating ligands among natural amino acids. We present a new class of ArMs featuring a genetically encoded noble‐metal‐binding site based on a non‐canonical thiophenol‐based amino acid, 4‐mercaptophenylalanine (pSHF), incorporated in the transcriptional regulator LmrR via stop codon suppression. We demonstrate that pSHF is an excellent ligand for noble metals in their low oxidation states. The corresponding gold(I) enzyme was characterised by mass spectrometry, UV‐vis spectroscopy and X‐ray crystallography and successfully catalysed hydroamination reactions of 2‐ethynyl anilines with over 50 turnover numbers. Interestingly, two equivalents of gold(I) per protein dimer proved to be required for activity. Up to 98% regioselectivity in the hydroamination of an ethynylphenylurea substrate was obtained, yielding the corresponding phenyl‐dihydroquinazolinone product, consistent with a π‐activation mechanism by single gold centres. The ArM was optimized by site saturation mutagenesis, using an on‐bead screening protocol. This resulted in a single mutant that showed higher activity on one class of substrates. This work brings the power of noble‐metal catalysis into the realm of enzyme engineering and establishes thiophenols as alternative ligands for noble metals, providing new opportunities in coordination chemistry and catalysis.

The effect of acceptor and donor doping on the electronic properties of the half-Heusler TiNiSn.

Optimizing the electronic transport properties of thermoelectric compounds is commonly achieved by either donor or acceptor atom doping to increase the conduction of the appropriate carrier type, electrons or holes, respectively. Enhancing carrier mobility and carrier concentration will both lead to optimized electronic properties. In this work the effect of various dopants on the electronic properties of TiNiSn was explored, by modeling the doping of an ideal compound on the Ti-sublattice with acceptor or donor elements. Using ab initio DFT calculations and a set of analytical expressions of transport properties, the temperature dependencies of the electronic properties were calculated, to examine possible n-type or p-type dopants to be used in further experimental studies.

ETS-NOCV description of chemical bonding: from covalent bonds to non-covalent interactions

ContextThe interpretation of ETS-NOCV for typical covalent and dative-covalent chemical bonds is presented and compared with that for halogen bonds. Possible tuning of the strength of halogen bonding is considered, first by applying an electric field (modeled by the point charges or the electric field vector), and then by constructing a model transition-metal complex with enhanced strength of halogen bonding. For all the systems, the ETS-NOCV picture is supplemented by the analysis of the deformation in molecular electrostatic potential (ΔMEP). The results demonstrate important characteristic features of the analysis based on NOCV: (i) this approach is based on pairs of orbitals with antibonding and bonding character and, thus, allows us to “extract” the “diatomic-like” picture of chemical bonding; (ii) the NOCV-pair contributions to the deformation density often correspond to donation (AB) and back-donation (AB) of electron density between the fragments. The results for halogen bonding demonstrate that it is possible to tune their strength by an electric field in the molecular environment; the halogen-bond energy can reach the order of magnitude typical of dative-covalent bonds. However, the nature of halogen bonds still differs from that of dative-covalent interactions, as the accumulation of electron density between fragments is of significantly lower magnitude. The main effect of the electric field is an increase in the polarization of the fragments, which is clearly manifested by the deformation in the MEP.MethodsAll calculations were performed using the ADF/AMS package. The BLYP exchange–correlation functional was employed with Grimme’s dispersion correction (D3 version) and Becke-Johnson damping, using TZP basis sets. The deformation in the MEP was determined as ΔVr=VABr-VAr-VBr, with the same fragment definition as in the ETS-NOCV method.

Valence tautomerism, non-innocence, and emergent magnetic phenomena in lanthanide-organic tessellations.

Coordination networks based on lanthanide ions entangle collective magnetic phenomena, otherwise only observed in inorganic 4f materials, and the tunable spatial and electronic structure engineering intrinsic to coordination chemistry. In this review, we discuss the use of 2D-structure-directing linear {LnII/IIII2} nodes to direct the formation of polymeric coordination networks. The equatorial coordination plasticity of {LnII/IIII2} results in broad structural diversity, including previously unobtainable tessellations containing motifs observed in quasicrystalline tilings. The new phases host also magnetic frustration, which is at the origin of enhanced magnetic refrigeration potential. Finally, careful redox matching of Ln node and frontier orbitals of the ligand scaffold has culminated in the discovery of quantitative valence tautomeric conversion in a molecule-based Ln material, opening up new avenues for combining exotic magnetic phenomena with an encoded switch.

Coordination Complexes of Cobalt with Pyrazole-Based Ligands and Potential Applications

Transition metals are one of the central aspects of modern coordination chemistry research. In addition to being well-studied, cobalt is a unique transition metal due to its presence in vitamin B12. Pyrazole-based structures are common in nature and organic synthesis. Over the past decade, our research group has focused on synthesizing and characterizing novel cobalt, nickel, and copper organometallic complexes. To date, we have reported three cobalt complexes, five nickel complexes and one copper complex with pyrazole-derived ligands. Based on the current scientific data, we are optimistic about potential applications of our coordination complexes with cobalt and pyrazole-based ligands. In this work we review applications of cobalt complexes with pyrazole-based ligands described in recent literature to explore possible applications of compounds synthesized and characterized by our research group.

Strategic management of the chemical complex taking into account the provisions of the ESG concept

The article presents the results of the analysis of the main characteristics of the development of chemical enterprises, which allowed us to conclude that there are positive trends in the development of the industry, which, according to certain indicators, is even significantly ahead of other industries that are more dependent on imported raw materials, materials, machinery and equipment. The article also notes that domestic enterprises have better development rates than foreign companies related to this sector of the economy. It is shown that in modern economic conditions, in order to ensure sustainable development of chemical enterprises in the strategic perspective, it is relevant to implement the provisions of the ESG concept, which includes principles related to a responsible attitude to the environment, which implies compliance with the requirements of environmental safety of production processes and consumption of products, as well as social responsibility and improving the quality of corporate governance of the enterprise. The article presents a system for monitoring the development strategy of chemical enterprises taking into account the provisions of the ESG concept, the formation of which will allow tracking the indicators of environmental safety of chemical industries, as well as assessing the effectiveness of the applied technologies for processing waste from production and consumption of chemical products, and making appropriate adjustments to the development strategy of the industry, if necessary.

Advances in the Light-Promoted Transformations of N-Heterocyclic Carbene Ligated Boryl Radicals

AbstractOrganoboron compounds are integral to modern life, with extensive applications in synthesis, materials science, medicine, and various other domains closely linked to human endeavors. NHC-BH3, noted for its stability, ease of synthesis, and high reactivity as a boryl radical precursor, has emerged as a key focus in boryl radical chemistry. Recently, the visible-light-induced single electron transfer (SET) and hydrogen atom transfer (HAT) processes have garnered considerable interest, presenting innovative strategies for generating boryl radicals from NHC-BH3. In the context of this review, our focus is on the synthesis of C–B and X–B bonds under visible light irradiation, facilitated by NHC-BH3. Furthermore, we explored the role of NHC-BH3 as a hydrogen donor or halogen atom transfer reagent in the construction of C–C bonds.1 Introduction2 Hydroboration3 Borylation4 Construction of X–B Bonds (X = N, O, S)5 Halogen Atom Transfer Reagent and Hydrogen Donor6 Conclusion

Alternative Solvents for Life: Framework for Evaluation, Current Status, and Future Research.

Life is a complex, dynamic chemical system that requires a dense fluid solvent in which to take place. A common assumption is that the most likely solvent for life is liquid water, and some researchers argue that water is the only plausible solvent. However, a persistent theme in astrobiological research postulates that other liquids might be cosmically common and could be solvents for the chemistry of life. In this article, we present a new framework for the analysis of candidate solvents for life, and we deploy this framework to review substances that have been suggested as solvent candidates. We categorize each solvent candidate through the following four criteria: occurrence, solvation, solute stability, and solvent chemical functionality. Our semiquantitative approach addresses all the requirements for a solvent not only from the point of view of its chemical properties but also from the standpoint of its biochemical function. Only the protonating solvents fulfill all the chemical requirements to be a solvent for life, and of those only water and concentrated sulfuric acid are also likely to be abundant in a rocky planetary context. Among the nonprotonating solvents, liquid CO2 stands out as a planetary solvent, and its potential as a solvent for life should be explored. We conclude with a discussion of whether it is possible for a biochemistry to change solvents as an adaptation to radical changes in a planet's environment. Our analysis provides the basis for prioritizing future experimental work to explore potential complex chemistry on other planets. Key Words: Habitability-Alternative solvents for life-Alternative biochemistry. Astrobiology xx, xxx-xxx.

Catalytic effect of the in-situ rhodium(III) complexes in surfactant medium on the auto-oxidation of 1,2-hydroxyphenylthiourea: A theoretical and experimental study for rhodium(III) sensing

1,2-hydroxyphenylthiourea(HPTU) undergoes auto-oxidation to form an yellow colored dimer. The process of auto-oxidation is enhanced by the presence of trace quantities of transition metal ions and transition metal complexes that act as catalysts. In the current study, catalytic potential of rhodium(III) complexes on the auto-oxidation of 1,2-hydroxyphenylthiourea(HPTU) was studied theoretically using quantum mechanical calculations and experiments were carried out using photometry and fluorometry. DFT studies inferred that [Rh(Py)6]Cl3 showed a better catalytic activity in the dimerization of HPTU. Theoretical studies were subsequently validated through experiments using photometric methods and the range of detection was determined to be 6 ng/mL–100 ng/mL. The detection limit was observed to be 2 ng/mL. Analytical parameters such as pH, reagent concentration, metal ion concentration, appropriate activators and surfactants were established.