State Structures Research Articles

Do not disarm, integrate: simultaneous inclusive conditions for successful integration

ABSTRACT This study examines the conditions under which insurgent groups can be successfully integrated into the state at political and military levels during post-conflict stabilization. While previous research emphasizes disarmament, demobilization, and integration, these steps are neither universal nor linear. Our research proposes an alternative approach: integrating insurgent groups into military and political institutions without requiring disarmament. This strategy hinges on a two-pronged method that divides insurgent groups into leaders and soldiers. Leaders are integrated into the political system, ensuring their power, legitimacy, and regional influence, while soldiers retain their arms within the military, reducing the risk of splinter groups and resentment. This approach provides insurgents with a compelling incentive to join state structures, discouraging a return to violent non-state activities. Through a mixed-methods analysis, including t-tests and case studies from the Philippines and El Salvador, we demonstrate that maintaining armed insurgents within state institutions reduces violence and fosters stability. This study builds on previous research by exploring tactics to draw insurgent groups into negotiations and offers significant contributions to state-building literature.

Russia and Turkey in the early 21st century: transformation of bilateral interaction models

In the article, the author undertakes an examination of three distinct periods in the history of Russian-Turkish relations. From a chronological perspective, these periods encompass the 2000s, the 2010s, and the first half of the 2020s. By the end of the first quarter of the 21st century, Russia and Turkey had begun to accord a higher level of priority to their relations with each other in a number of areas, including diplomatic interaction at the global and regional levels, trade and economic relations, energy and military-technical cooperation. This situation starkly contrasts with the late 1990s, when Turkey demonstrated a tendency to align with the “collective West” in a manner driven by both inertia and ideology. The author posits that Russian-Turkish relations have undergone a dynamic transformation over the past quarter of a century, while each of the periods under consideration exhibiting a unique constellation of complementarity and competition. These two aspects defined the respective models of bilateral relations in each period. Existing research focuses mainly on various discrete aspects of the relationship between the two countries – be it diplomatic interaction, energy, or issues of intertwined or competing interests in specific hotspots and regions such as Syria, Libya, the Middle East, Central Asia, and the Caucasus. At the same time, a comprehensive analysis of the driving forces behind the transformation of Russia-Turkey relations is still lacking in academic publications on Turkey. In order to present such an analysis, this article draws on a number of important primary sources, including official documents of Russian and Turkish state agencies and structures involved in the implementation of foreign policy, national statistics, publications of news agencies, and leading media.

Adaptive evaluation of gross total resection rates for endoscopic endonasal approach based on preoperative MRI morphological features of pituitary adenomas

ObjectiveThis study aims to define a set of related anatomical landmarks based on preoperative Magnetic Resonance Imaging (MRI) of patients with pituitary adenomas (PAs). It explores the impact of the dynamic relationships between different anatomical landmarks and the tumor on the resection rate and tumor progression/recurrence during the endoscopic endonasal approach (EEA).MethodsA single-center institutional database review was conducted, identifying patients with PAs treated with EEA from December 2018 to January 2023. Clinical data were reviewed, and anatomical landmarks were categorized into two regions: the suprasellar region and the cavernous sinus region. Following basic statistical and univariate logistic regression analyses, patients were randomly divided into training and validation sets. A nomogram was then established through the integration of least absolute shrinkage and selection operator (LASSO) regression and multivariable logistic regression analysis. The clinical prediction model was evaluated using the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis. Kaplan-Meier curves were plotted for survival analysis.ResultsA total of 626 patients with PAs were included in the study, with gross total resection (GTR) achieved in 570 cases (91.05%). Significant differences were observed in the distribution of age, Knosp grade, and tumor size between the GTR and near total resection (NTR) groups. LASSO regression identified 8 key anatomical landmarks. The resulting model demonstrated an AUC of 0.96 in both the training and validation sets. Calibration curves indicated a strong agreement between the nomogram model and actual observations. Survival analysis revealed that the extent of resection (EOR), age, Knosp grade, tumor size, and PAs extending beyond several anatomical landmarks identified were significantly associated with the progression or recurrence of PAs.ConclusionThis study proposes a model for adaptively assessing the resection rate of PAs by delineating relevant anatomical landmarks. The model comprehensively considers instrument manipulation angles, surgical accessibility during EEA procedures, anatomical variations, and the displacement of related anatomical structures in pathological states. This approach can assist neurosurgeons in preoperative planning and developing personalized surgical strategies.

Enhanced ethylenediamine detection using WO3-BiVO4 nanoflakes heterostructure with exceptional adsorption capabilities: Experimental and theoretical studies.

The present work describes the synthesis of WO3-BiVO4- nanoflakes heterostructure (NFHs) by a single step hydrothermal method. The analysis of crystalline phases and structural behavior deduced the formation of good crystal quality WO3-BiVO4 NFHs. Under microscopic observation, the as-prepared WO3-BiVO4 displayed uniform and conspicuous nanoflakes like structures. The extensive density functional theory (DFT) was studied to examine the electronic and band structures of as-prepared WO3-BiVO4 NFHs in terms of formation energy, charge density, density of state (DOS) and band structures. The synthesized WO3-BiVO4 NFHs was used as sensing electrode towards the detection of ethylenediamine (EDA) chemical that displayed a good sensitivity of ~318.52 mA.mM-1cm-2, excellent dynamic range of 1 μM - 1 mM with detection limit (LOD) of ~94.51 nM and retention coefficient of ~0.9929. WO3-BiVO4 NFHs electrode possessed the good reproducibility, stability, and repeatability towards EDA chemical. To the best of our knowledge, for the first time, the fabricated chemical sensor fabricated with WO3-BiVO4 NFHs electrode could be promising electrode materials to identify dangerous chemicals at very low concentration in environment. Importantly, the fabricated chemical sensor can be effective for environmental monitoring.
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Trends in Civil War Research on South Sudan (2013–2023): A Bibliometric Analysis

This study examines the evolution of civil war research focused on South Sudan from 2013 to 2023, employing bibliometric analysis to evaluate 120 articles from the Scopus database. The findings reveal key trends, including the thematic transition from exploring the origins and impacts of conflict during the wartime period (2013–2017) to addressing post-conflict recovery and reform following the Revitalized Agreement on the Resolution of Conflict in South Sudan (R-ARCSS) in 2018. Frequently discussed topics include ethnicity, kleptocracy, and weak state structures during wartime, and reconciliation, sustainable peacebuilding, and social recovery in the post-conflict period. The study identifies significant contributions from prolific authors, geographical patterns in research output, and under-researched areas such as human rights and peacekeeping. By highlighting bibliometric trends and key thematic clusters, the article offers actionable insights for policymakers, scholars, and international stakeholders invested in conflict resolution and peace studies.

A New Bis-Urea Based Cage Receptor for Anions: Synthesis, Solid State Structures and Binding Studies.

The synthesis and characterization of a novel bis-urea-based cage receptor for anions (3S,15S)-3,15,20,25-tetramethyl-1,4,6,12,14,17,20,25-octaazatricyclo[15.5.5.17.11]octacosa-7(28),10-diene-2,5,13,16-tetraone (L) is reported. L is a macro-bicyclic ligand built on the 1,7-dimethyl-1,4,7,10-tetraazacyclododecane scaffold to obtain a cage topology in which two ureido moieties have been inserted as binding sites for anions. L can interact with anion guests (G) via H-bonding; in particular, it binds both spherical (Cl-) and V-shaped anions (AcO-) as well as more complex carboxylate anions, such as the norfloxacin (Nor-). NMR experiments highlight that the interaction between L and G mainly occurs at the ureido moieties. L forms L-G adducts of 1 : 1 ([LG]-) and 1 : 2 ([LG2]2-) stoichiometry with Cl- and AcO-. Otherwise, in the case of Nor- only the formation of the [LG]- complex is observed. L shows higher formation constants values for [LAcO]- (2.9) and [LNor]- (3.6) than [LCl]- suggesting a stronger interaction with the carboxylate anions. In the solid state, three crystal structures of the HL⋅G species were obtained (G=Cl-, AcO-, ClO4 -) highlighting the H-bonding interaction between the chloride, acetate or perchlorate anions and the -NH functions of the ureido fragment. The comparison between the two parent open chain receptors (Lb-c) and L has been reported and discussed.

Фактори поширення корупції в органах державної влади України: аналіз та особливості

The article examines and highlights in detail the key factors of the existence and spread of corruption in the state authorities of Ukraine. The dynamics of the International Corruption Perception Index were analyzed and it was established that over the past ten years this indicator had a tendency to gradually improve, which was facilitated by the increase in the positive image of the state in the direction of the implementation of anti-corruption reforms at the international level, in particular, the signing of the Association Agreement, the development of the Visa Liberalization Action Plan with the European Union, the European Commission's recommendation to grant Ukraine the status of a candidate for accession. It has been established that one of the main sources of corruption in society and the state is a social crisis, which is accompanied by a high level of contempt for the law, legal nihilism, moral instability, and the phenomenon of corruption in Ukraine is closely interconnected with the political system of the state, the main reasons for this are also determined, among the key factors of which are irresponsibility and insufficient level of its controllability. Among other reasons, the following are highlighted: the presence of many bureaucratic permitting procedures, prohibitions on the implementation of a certain type of activity; lack of proper public control by civil society institutions; lack of a clear division of competence between state structures; weakness of anti-corruption policy, selective approach in the work of anti-corruption bodies and political engagement. It is emphasized that the development of corruption is facilitated by growth, as well as a significant share of the country's shadow economy. According to the results of the conducted research and generalization, six groups of causes and factors of the emergence and development of corruption in the state bodies of the country are distinguished: fundamental or political factors, legal, organizational-economic, informational, social and cultural-historical factors. A list of priority measures to eliminate corruption in state authorities by reforming interrelated systems of public administration and prevention of corruption is proposed

Measuring libertarian ideology with party manifesto data

ABSTRACT Libertarian ideology espouses a distinct political project which seeks to revolutionise the structures of the liberal democratic state. Surprisingly, this radical worldview does occasionally influence mainstream right-wing parties, and libertarian ideologues within their ranks have, at opportunistic moments, been able to encourage their desired policy change. But how can we measure these shifts in libertarian ideas within political parties? First, this study explains the design of a novel measure for libertarianism using the Manifesto Project Database. Second, it will apply this libertarian measure to the political parties of the United States and several European countries to test its face validity. Finally, the ‘crucial case’ of libertarian ideas within the UK Conservative Party will be assessed through the measure. This article finds that the libertarian scale provides a valid and utilitarian measure for libertarian ideology, which should prompt further research.

Investigation of the Structural, Vibrational, Electronic, and optical properties of energetic Nitrogen-Rich azidotetrazolates XCN7 (X = N2H5, NH4, K, Cs)

In this work, we present a detailed and comparative study of four salts of 5-azido-1H-tetrazole using Density Functional Theory (DFT) based computational methods. The salts, containing the CN7- anion, include hydrazinium azidotetrazolate (N2H5CN7), ammonium azidotetrazolate (NH4CN7), potassium azidotetrazolate (KCN7), and cesium azidotetrazolate (CsCN7). These compounds are collectively represented as XCN7, where X = N2H5, NH4, K, and Cs. We found that the incorporation of van der Waals interactions was crucial in aligning the theoretical ground state structures with experimental data. Mechanical stability of all the compounds within their respective space groups was verified by calculating the elastic constants and bulk modulus. Vibrational frequency analysis revealed that N2H5CN7 and NH4CN7, containing NH bonds, exhibited frequencies around 3300 cm−1, while the metal salts KCN7 and CsCN7, lacking NH bonds, showed frequencies below 2000 cm−1. Born effective charge calculations indicated strong covalency within the tetrazole ring and between C, N, and H atoms, contrasted by the ionic nature of the metal atoms. Using the TB-mBJ potential, we accurately computed the electronic structure and optical properties, predicting bandgaps and absorption edges for these XCN7 compounds. The partial density of states analysis highlighted the significant role of C and N p states in the sensitivity of these compounds. Optical property evaluations confirmed that these compounds are optically anisotropic, exhibiting low sensitivity in the visible region but high sensitivity in the UV and far UV regions. These insights are crucial for predicting and controlling their reactivity, stability, and performance in various applications, particularly in the field of energetic materials.

Popular assemblies as historical prototypes of parliamentarism

Relevance. The emergence of parliamentary mechanisms in the European space is the result of a strong political and legal tradition. Before parliaments acquired the status of state structures, society developed special representative institutions - prototypes of parliamentarism, which are rightly considered popular assemblies. The analysis of their legal status and functionality is a promising scientific direction, as it allows us to generate regularities and factors of parliamentarism as a unique category. Purpose: generalization of retrospective experience of people’s assemblies in the context of their positioning as proto-parliamentary models. Objectives: to study the empirical basis for the functioning of popular assemblies in the format of ecclesia, commissions, tings and veche, to determine the «points of influence» of these structures on the fixation of parliamentary values in national legal orders.Methodology. The methodology of the research is represented by a combination of general scientific, private scientific and special legal methods, among which the comparative legal method is of particular importance.Results. The results of the study are of theoretical and applied nature and consist in a summarized view of the competence toolkit of popular assemblies operating in different historical periods on the territory of the European continent and their role in the subsequent establishment of parliamentary principles.Conclusions. Popular assemblies in the format of ecclesia, commissions, tings and veche, accompanying the development of the state system of various countries and epochs, were peculiar stimuli for the formation of parliamentarism, which acquired a stable reputation as the social architecture became more complex and deliberative structures were introduced into the managerial conjuncture. The experience of people's assemblies largely predetermined the further emergence of parliaments as a natural result of the development of social relations.

Protonation Weakens the Influence of Ribose on Triplet Decay of 2-Thiocytidine.

Long-lived triplet states are critical intermediates of thiobases for their applications in photodynamic therapy and as photoprobes for DNA/RNA-protein interactions, where thiobases are embedded in DNA/RNA and exist as thionucleosides. However, sugar moieties accelerate triplet decay rates, which is a common issue that must be resolved for thionucleosides. Here, we explore whether protonation of 2-thiocytosine (2tCyt) and 2-thiocytidine (2tCyd) under acidic pH can alter their triplet decays. Femtosecond spectroscopy demonstrates that 2tCytH+ and 2tCydH+ exhibit similar triplet lifetimes (3.1 ns), suggesting protonation diminishes the influence of ribose on triplet decay. Notably, the triplet lifetime of 2tCydH+ is 2-fold prolonged compared to 2tCyd. Further calculations reveal protonation effectively weakens the influence of ribose by altering electronic structures of triplet states and inhibiting the photoisomerization leading to rapid decay. These findings point to a new avenue of using protonation to modulate triplet decay dynamics of thionucleosides and develop pH-responsive strategy in photochemical applications.

КОРПОРАТИВНА СОЦІАЛЬНА ВІДПОВІДАЛЬНІСТЬ ЯК КЛЮЧОВИЙ ІНСТРУМЕНТ ЕКОНОМІЧНОЇ БЕЗПЕКИ БІЗНЕСУ ПІД ЧАС ВІЙНИ

Today's state of war is dramatically changing the business environment, creating unprecedented challenges for businesses of all sizes. The instability of the political situation, the disruption of logistics chains, a decrease in investment and a decrease in the purchasing power of the population have a negative impact on economic activity. Enterprises face increased risks, which requires a review of management strategies and ensuring economic security as a basis for further functioning and development. In these conditions, corporate social responsibility (CSR) becomes especially important, becoming not only an ethical imperative, but also a strategic tool for increasing business sustainability. The active participation of companies in solving social and humanitarian problems during martial law strengthens their authority and trust on the part of society and stakeholders, which contributes to the formation of a positive image, the expansion of partnership relations and the creation of additional opportunities for stable functioning in conditions of uncertainty. The growing role of CSR as a component of the enterprise management strategy provides an opportunity not only to preserve the economic security of individual business entities, but also to strengthen public trust in business, which is a key element of ensuring long-term economic stability in Ukraine.Objective.Theoretical generalization of scientific approaches regarding the content and role of corporate social responsibility as the main tool for ensuring the economic security of business in the conditions of martial law in Ukraine and the development of methodological recommendations for strengthening the stability and adaptability of business to crisis conditions. Results. The article provides a theoretical generalization of scientific approaches to the content and role of corporate social responsibility as a key tool for the economic security of business during the martial law in Ukraine. On the basis of scientific approaches, a modern interpretation of the CSR pyramid of Archie B. Carroll was formed. The analysis and assessment of the losses of infrastructure and enterprises of the real sector of the economy of Ukraine from hostilities and missile terror was carried out; an assessment of the main macroeconomic indicators of Ukraine for 2018-2023 is provided, the impact of military operations on a significant reduction in the number of active enterprises and the number of employees and the population of Ukraine in 2018-2023 is determined. The conducted studies highlight the key areas of CSR implementation in wartime, in particular, support for employees, assistance to the mobilized, involvement of stakeholders in the formation of the company's strategy and brand promotion. Scientific novelty. Approaches and methods of their involvement in the establishment of communications and interaction with stakeholders - investors, local communities and state structures are proposed, which will allow companies to adapt more quickly to the challenges of war. Practical significance. To ensure the economic security of business during wartime, it is proposed to integrate new initiatives to support personnel, mobilized workers and their families, as well as local communities. Such an approach will not only contribute to the stability and functionality of the enterprises themselves, but also strengthen their social stability and economic security, provide a deep connection between business and society, which contributes to the long-term development and socio-economic stability of the country in conditions of war. Keywords: corporate social responsibility (CSR), economic responsibility, enterprises, Archie Carroll's pyramid model, stakeholders, business economic security, development strategy, war.

Heterojunction Organic Solar Cells with Efficient Charge Mobility and Separation Capabilities Studied by DFT.

The properties of the active layer materials play a decisive role in determining the power conversion efficiency of organic solar cells (OSCs). Chlorophyll and its derivatives are abundant and environmentally friendly functional organic molecular materials. Using density functional theory (DFT) and time-dependent density functional theory (TD-DFT), we have calculated the absorption spectra and their excited state properties based on optimized ground state structures. It was found that bacteriochlorin exhibits superior structural properties, a smaller energy gap and hole reorganization energy, redshifted absorption spectra, and higher hole mobility compared to the donor D18. This suggests that bacteriochlorin exhibits superior donor properties. Comparative studies between o-AT-2Cl and m-AT-2Cl showed that o-AT-2Cl had superior acceptor properties, implying that differences in substitution positions can influence the physicochemical properties of non-fullerene acceptors (NFAs). Subsequently, six bulk heterojunctions (BHJs) were constructed by combining three donors with nonfused ring electron acceptors, o-AT-2Cl and m-AT-2Cl. The bacteriochlorin-based BHJs performed well among them, with BChl3/o-AT-2Cl and BChl4/o-AT-2Cl having the largest interfacial charge separation rate. The results suggested that BHJs composed of bacteriochlorin and NFAs can improve OSCs' photovoltaic performance, providing a feasible scheme for designing efficient OSCs.

A theoretical exploration of the influence of oxygen element on photo-induced behaviours for flavonoid derivatives with Me2N substitution

The exceptional properties of flavonoid derivatives are a great inspiration for our research. In the fields of medicine and chemistry, flavonoids present the superior ability to enhance non-specific immune function and humoral immune response. Herein, our primary focus lies in the theoretical exploration of the photo-induced characteristics exhibited by the novel Me2N-substituted flavonoid (MEF) fluorophore. Considering the potential photo-induced properties associated with chalcogen atomic electronegativity in photoexcitation, using density functional theory (DFT) and time-dependent DFT (TDDFT) methods, we primarily pay attention to probing into photo-induced hydrogen bonding effects and concomitant charge reorganisation processes. Given changes in chemical geometries and the infrared (IR) vibrational shifts of three MEF derivatives (MEF-O, MEF-S and MEF-Se), we confirm that intramolecular hydrogen bonding should be strengthened by facilitating excited state intramolecular proton transfer (ESIPT) reactions. Particularly, the redistribution of charge further shows the ESIPT behaviour. By constructing potential energy curves (PECs) and identifying transitional reaction state (TS) structures, we ultimately validate the electronegativity-dependent ESIPT mechanisms of chalcogen elements in MEF derivatives. We sincerely hope that our work can accelerate future development and applications of flavonoid derivatives.

The role of journalists of the State Border Guard Service in military journalism in Ukraine

Modern Ukrainian media and communicators pay great attention to military journalism. Today, this field is gaining popularity in Ukraine and the world, as more and more media representatives work in conditions that threaten their health and lives. The challenges of hybrid warfare make scientists more interested in military topics, as the war is waged on two fronts — military and informational. The article considers the stages of formation and development of Ukrainian military journalism, focusing on its current state. Attention is drawn to the state of scientific research of modern military journalism. The role of journalists in the uniform of the State Border Guard Service of Ukraine (SBGSU) is actualized. We emphasized the need to popularize the military journalists, their contribution to the development of Ukrainian journalism. The main directions of activity of the SBGSU journalists are analyzed and determined their place and role in modern military media. The functions and tasks of military journalism, the rights and obligations of combatant journalists while serving both in the war zone and in peaceful areas of the Ukrainian border are separately considered. The main tasks include covering the activities of the SBGSU and preparing materials for the media; information support for the internal work of the service; prompt response to events; work with regional and national media; countering disinformation; coordination with other state structures. The results can be used in the development of educational programs in military and civilian educational institutions, as well as in retraining courses for civilian correspondents who plan to work in the war zone.

Substitution effect and charge transport properties in organic field-effect transistors (OFETs) of simply functionalized carbazole derivatives

Development of low cost, easy-preparation and good performance organic semiconductors is in high demand for the practical application of organic field-effect transistors (OFETs). Even though the π-extended carbazole derivatives have been intensively studied in OFETs, the application potential of simple carbazole derivatives, i.e., owning simple substituents directly at carbazole backbone, remains unclear. In this work, we designed and synthesized a series of carbazole derivatives with simple phenyl or thienyl functionalization directly at 2,7- or 2,6-positions, respectively. The photophysical and electrochemical properties, together with their theoretical frontier molecular orbitals and energy levels were investigated. The molecular conformations and packing structures in the solid state of these molecules were understood by single-crystal structure analysis. In addition, single-crystal based OFETs were fabricated to explore their intrinsic charge transporting properties, in which the 2,7-diphenyl modified carbazole derivative showed hole-transporting mobilities up to 0.16 cm2 V−1 s−1. Our study not only proves that simply functionalized carbazoles have great potentials to act as easy-preparation high-performance p-type semiconducting materials, but also illustrates that 2,7-positon functionalization is more advantageous for balancing the molecular conformations and packing structures of carbazole derivatives to achieve good charge transport performance.

Alkyl initiated ring opening polymerization of lactide by indium complexes supported by NCN pincer ligands.

Indium-alkyl NCN pincer complexes supported by amine and imine donors are active catalysts for the ring opening polymerization of lactide. The amine indium complexes are significantly more active for polymerization due to the decoordination of the amine donors at higher temperatures. Solid state structures of the imine and amine indium complexes indicate that the imine-indium bonds are stronger than the analogous amine-indium bonds. Higher molecular weight polymers that were not observable by MALDI-TOF were shown to be linear by comparing their intrinsic viscocities with those of known linear polymers. The alkyl indium complexes are more active than the analogous alkyl aluminum complexes but are prone to transesterification reactions.

Possible structures of skyrmion states in chiral ferromagnetic films with spatially modulated uniaxial anisotropy.

In this paper, the stabilization conditions, structure, and properties of possible vortex-like inhomogeneities, including kπ-skyrmions k = 0, 1, 2, 3, 4, in a uniaxial multilayer disk with a columnar defect in the center are investigated based on micromagnetic modeling. Their stability diagrams depending on the Dzyaloshinskii-Moriya interaction, the magnitude of magnetic anisotropy and the defect parameters are determined. New types of vortex-like inhomogeneities that can arise in such samples are found. The obtained data can be used to create artificial regions of nucleation, capture and pinning of magnetic skyrmions, which can provide greater reliability of data storage in spintronic logical devices.&#xD.

Theoretical investigation of Diels–Alder reaction mechanism and regioselectivity with functionalized fullerene derivatives

AbstractDensity functional theory (DFT) was used to study the mechanism of Diels–Alder (DA) reaction between 2‐Methyl‐ 1,3 Butadiene (MBD) with B12N12, B6N6C12 and B6C12N6 fullerens in the gas phase. In this mechanism, B‐N bonds of four‐membered and six‐membered rings of nanocages were chosen to react with MBD. Due to the existence of two types of B‐N bonds, two competitive pathways (a and b) were investigated. The effect of the substitution of carbon atoms instead of boron and nitrogen atoms on the stability of the structures and the regioselectivity of the DA reaction was examined. The potential energy of all structures and the activation barrier for all reaction pathways was evaluated. The chemical reactivity of fullerens using the molecular quantum descriptors was assessed. To evaluate the global electron density transfer in transition states (TS) structures, the natural bond orbital (NBO) analysis was performed.

Solution and solid state structures of lanthanides(III) and uranyl(II) complexes of tripodal tris(2-pyridyl)-containing ligand on Ph3P(O) platform

Reaction of tris[2-(2′-pyridylmethoxy)phenyl]phosphine oxide (L) with f-element nitrates resulted in 1:1 complexes. The isolated complexes of ligand L with La(III), Eu(III), Tb(III), and U(VI) nitrates, and with La(III) chloride were studied in the solid state and solution by IR, Raman, and NMR spectroscopy, X-ray analysis, and also DFT calculations. Composition and structure of the complexes vary with lanthanide cation radius. According to the data of elemental analysis, vibrational spectroscopy, and X-ray diffraction, the ligand is coordinated in tridentate mode in crystalline La(III) and solid Eu(III) complexes: [Ln(OPO,N,Oeth-L)(H2O)(O,O-NO3)3], and in monodentate mode in crystalline complex [Tb(OPO-L)(H2O)2(O,O-NO3)3]. Nitrogen atoms of pyridine fragments of the ligand not involved in coordination produce intra- and intermolecular H-bonds with coordinated water molecules in the second coordination sphere of Ln(III). According to IR, NMR spectrometry, and DFT calculations, the structure of coordination polyhedron of the main species of Ln(III) complexes in acetonitrile solutions is retained including coordination of one of pyridine fragments in the second coordination sphere: [Ln{OPO,N,(N*),Oeth-L}(H2O)(O,O-NO3)3] and [Tb{OPO,(N*)-L}(H2O)2(O,O-NO3)3], where Ln = La, Eu, and N* is the nitrogen atom of pyridine fragment producing intramolecular H-bond with coordinated water molecule. According IR and Raman spectroscopy, ligand L is coordinated in bidentate mode in solid complex [UO2(OPO,N-L)(O,O-NO3)], and uncoordinated nitrogen atoms remain free. Solution structure of uranyl complex is labile and depends on solvent nature. Equilibria of complex species with variable coordination of nitrate ions, ligand L, and with probable involvement of water take place in CD3CN and CDCl3 solutions. Photophysical properties of the prepared Eu(III) and Tb(III) complexes were studied. The preliminary assessment of extraction properties of compound L was made. Stability of studied compounds in acetonitrile solutions was examined, and the structure of one of protolysis product of Eu(III) complex, [Eu(LH)(H2O)(NO3)4], was established by micro-IR and X-ray analysis.