Coordination Mode Research Articles

Synthesis and photoluminescent spectroscopic analysis of lanthanum (III) coordinated with 1,10-Phenanthroline: A study of its thermally stable behavior

A blue-emitting phosphor designed by lanthanum (III) coordinated with two 1,10-Phenanthroline and three nitrate ligands, [La(Phen)2(NO3)3], was obtained by an effective and simple precipitation method. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) revealed the coordination modes in the compound and the chemical structure, crystallizing in a monoclinic system in the C2/c space group. The luminescence properties, absolute quantum yield (ϕ), and luminescence lifetime decay (τ) were determined by photoluminescence spectroscopy. Under a 350 nm excitation, the sample presents three emission bands corresponding to the π* → π transitions belonging to the organic ligand. The luminescence lifetime (τ) was determined through a monoexponentially fit, obtaining a value of 5616 ns. The [La(Phen)2(NO3)3] complex exhibits an absolute quantum yield of 3 % with the same excitation conditions. In addition, the photometric analysis shows that the luminescent response to a 350 nm excitation is that of a blue-emitting high-purity phosphor with 96 % and chromatic coordinates of 0.15, 0.05. The temperature-dependent luminescence properties revealed considerable thermal stability in the 20–150 °C range with a signal loss of 47 % and an activation energy of thermal quenching (ΔE) of 0.13 eV, the first value reported for a lanthanum complex based on 1,10-Phenanthroline.

Silver(I) complexation with N-donor heterocyclic ligands in the presence of boron cluster anions: Synthesis and coordination features

Silver(I) complexation with boron cluster anions [BnHn]2− (n = 10, 12) and chelating 1-substituted-2-aldiminebenzimidazoles 1-(1-methylbenzimidazol-2-yl)-N-phenylmetanimine (L1) and 1-(1-benzylbenzimidazol-2-yl)-N-cyclohexylmethanimine (L2) in systems AgNO3/[BnHn]2−/L and {Ag2[BnHn]}m/L, as well as with azaheterocyclic ligands 2,2ʹ-bipyridine (bipy) or 1,10-phenanthroline (phen) in the system AgNO3/[BnHn]2−/L has been first studied. The effect of the organic ligand on the composition and structures of the resulting compounds has been shown. As a result, binuclear complexes [Ag2L2[μ–BnHn]] with bridging boron cluster anions with various combinations of coordination modes (edge-edge and edge-face for the [B10H10]2− anion, edge–atom and nontrivial asymmetric for the [B12H12]2− anion) have been synthesized and structurally characterized for benzimidazole derivatives L1 and L2. When using bipy or phen as ligands, polymeric complexes {Ag2L[B10H10]}m or {Ag2L2[μ-B12H12]}m have been obtained.

Experimental and theoretical studies for instantaneous detection of l-cysteine and l-histidine using a simple Cu(II)-dppy complex

Developing simple and effective receptors for instantaneous detection of l-amino acids is vital for the recognition of life-threatening diseases in their early stage. Here, we report the synthesis and characterization of 2,6-di(pyrazin-2-yl)pyridine (dppy) based ligand L (L = 2,2′-(4-(3,4-diethoxyphenyl)pyridine-2,6-diyl)dipyrazine) and its copper (II) complex, [Cu(NO3)2L]. The in-situ prepared [Cu(H2O)2L](NO3)2 receptor in aqueous acetonitrile (4:1 v/v, 10 mM HEPES buffer, pH 7.4) medium displayed instantaneous responses towards biologically important bio-thiol l-Cysteine (Cys) and essential amino acid l-Histidine (His) over other l-amino acids through UV–Visible absorption spectral studies. Additionally, the competitive experiments confirmed that in-situ prepared [Cu(H2O)2L](NO3)2 receptor selectively detects Cys (1 equivalent) in the presence of other l-amino acids. The detection limits of Cys and His were calculated to be 8.23 × 10−7 M and 2.55 × 10−6 M, respectively. The density functional theory (DFT) calculation shows that selectivity of [Cu(H2O)2L](NO3)2 towards Cys is due to the reduction of Cu(II) to Cu(I) in the presence of Cys, while Cys is oxidized to cystine (Cys-Cys). For His, selectivity observed due to the formation of [Cu(His)2] moiety between Cu(II) ion with one His via N,O coordination mode and another His via N,N,O-coordination mode.

Research on the coupling coordination and spatial spillover effect of industrial development and environmental protection

ABSTRACT Analysing the coordination and spatial spillover effects between industrial development and environmental protection is crucial for regional sustainable development. This paper examines the spatial and temporal evolution characteristics of the coupling coordination level between industrial development and environmental protection, as well as the evolution of the decoupling type within this system. under the evolution of the coupling coordination mode and decoupling model. Additionally, it analyzes the spatial spillover effects using the spatial panel vector autoregression model. The main conclusions are as follows: First, the coordination level between industrial development and environmental protection is increasing over time in each province. Second, the decoupling status of industrial development and environmental protection shows distinct stages, progressing towards strong decoupling over time. Third, regional industrial development has a positive spillover effect on both industrial development and environmental protection in neighbouring regions, whereas regional environmental protection has a negative spillover effect on industrial development but a positive spillover effect on environmental protection in neighbouring regions. This paper suggests that provinces should focus on the synchronisation industrial development and environmental protection and implement differentiated strategies based on their specific conditions. Additionally, joint management and governance should be pursued between neighbouring provinces.

Metal(triphenylphosphine)-atovaquone Complexes: Synthesis, Antimalarial Activity, and Suppression of Heme Detoxification.

To ascertain the bioinorganic chemistry of metals conjugated with quinones, the complexes [Ag(ATV)(PPh3)2] (1), [Au(ATV)(PPh3)]·2H2O (2), and [Cu(ATV)(PPh3)2] (3) were synthesized by the coordination of the antimalarial naphthoquinone atovaquone (ATV) to the starting materials [Ag(PPh3)2]NO3, [Au(PPh3)Cl], and [Cu(PPh3)2NO3], respectively. These complexes were characterized by analytical and spectroscopical techniques. X-ray diffraction of single crystals precisely confirmed the coordination mode of ATV to the metals, which was monodentate or bidentate, depending on the metal center. Both coordination modes showed high stability in the solid state and in solution. All three complexes showed negative log D values at pH 5, but at pH 7.4, while complex 2 continued to have a negative log D value, complexes 1 and 3 displayed positive values, indicating a more hydrophilic character. ATV and complexes 1-3 could bind to ferriprotoporphyrin IX (FePPIX); however, only complexes 1-3 could inhibit β-hematin crystal formation. Phenotype-based activity revealed that all three metal complexes are able to inhibit the growth of P. falciparum with potency and selectivity comparable to those of ATV, while the starting materials lack this activity. The outcomes of this chemical design may provide significant insights into structure-activity relationships for the development of new antimalarial agents.

Synthesis, structure, and photochromic properties of Zn-coordination polymers derived from hexyl viologen cations

This study presents the synthesis, structural characterization, and investigation of the photochromic properties of two Zn-coordination polymers, formulated as {(HV)0.5[Zn(MIC)(HMIC)]·H2O}n (1) and {(HV)2[Zn4(BTEC)3]}n (2) (H2MIC = 5-methylisophthalic acid, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, HVBr2 = 1,1′-bis(n-hexyl)-4,4′-bipyridinium dibromide), derived from hexyl viologen cations. Compound 1 is characterized by a one-dimensional (1D) structure, while compound 2 exhibits a three-dimensional (3D) architecture, both crystallizing in distinct space groups and showcasing unique assembly and composition. Detailed structural analysis reveals the coordination modes of Zn(II) ions within these polymers. The photochromic behavior of two compounds under UV light exposure was thoroughly examined through ultraviolet-visible (UV–vis) and electron paramagnetic resonance (EPR) spectroscopy, demonstrating reversible color changes from light yellow to blue upon irradiation, with distinct rates of decolorization indicative of the stability of photo-induced viologen radicals. This reversibility was successfully replicated over multiple cycles, underscoring the durability of the photochromic transition. Furthermore, powder X-ray diffraction (PXRD) data confirmed the maintenance of crystal structures throughout the photochromic process, dismissing photolysis or photo-induced isomerization as underlying mechanisms. Instead, the observed photochromism is attributed to efficient electron transfer facilitated by the proximity between electron-donating and electron-withdrawing groups within the coordination polymers. This study highlights the influence of structural parameters on the photochromic properties of viologen-based coordination polymers, offering insights into the design of photo-responsive materials.

From d8 to d1: Iron(0) and Iron(I) Complexes Complete the Series of Eight Fe Oxidation States within the TIMMNMes Ligand Framework.

Reduction of the ferrous precursor [(TIMMNMes)Fe(Cl)]+ (1) (TIMMNMes = tris-[(3-mesitylimidazol-2-ylidene)methyl]amine) to the low-valent iron(0) complex [(TIMMNMes)Fe(CO)3] (2) is presented, where the tris(N-heterocyclic carbene) (NHC) ligand framework remains intact, yet the coordination mode changed from 3-fold to 2-fold coordination of the carbene arms. Further, the corresponding iron(I) complexes [(TIMMNMes)Fe(L)]+ (L = free site, η1-N2, CO, py) (3) are synthesized and fully characterized. Complexes 1-3 demonstrate the notable steric and electronic flexibility of the TIMMNMes ligand framework by variation of the Fe-N anchor and Fe-carbene distances and the variable size of the axial cavity occupation. This is further underpinned by the oxidation of 3-N2 in a reaction with benzophenone to yield the corresponding, charge-separated iron(II) radical complex [(TIMMNMes)Fe(OCPh2)]+ (4). We found rather surprising similarities in the reactivity behavior when going to low- or high-valent oxidation states of the central iron ion. This is demonstrated by the closely related reactivity of 3-N2, where H atom abstraction with TEMPO triggers the formation of the metallacycle [(TIMMNMes*)Fe(py)]+ (5), and the reactivity of the highly unstable Fe(VII) nitride complex [(TIMMNMes)Fe(N)(F)]3+ to give the metallacyclic Fe(V) imido complex [(TIMMNMesN)Fe(NMes)(MeCN)]3+ (6) upon warming. Thus, the employed tris(carbene) chelate is not only capable of stabilizing the superoxidized Fe(VI) and Fe(VII) nitrides but equally supports the iron center in its low oxidation states 0 and +1. Isolation and characterization of these zero- and monovalent iron complexes demonstrate the extraordinary capability of the tris(carbene) chelate TIMMN to support iron in eight different oxidation states within the very same ligand platform.

A mixed polynuclear clusters-based Y-MOF with an unprecedented (12, 12, 18)-c topology: highly efficient propylene/ethylene separation and iodine adsorption

The design and synthesis of highly stable metal–organic frameworks (MOFs) bearing unpredictable polynuclear clusters and new topologies are important for the development of novel and complicated MOFs. Herein, the polynuclear rare-earth (RE) clusters with more coordination modes and the small V-shaped ligand (2,5-thiophenedicarboxylic acid) were chosen, and subsequently JLU-MOF132 with three different yttrium clusters (two independent Y6 and one Y9 clusters) and a novel (12, 12, 18)-connected topology was successfully synthesized. Notably, JLU-MOF132 exhibits high porosity, excellent thermal, acid-base, and solvent stabilities. JLU-MOF132 shows considerable potential in methanol-to-olefins (MTO) products (C3H6 and C2H4) separation. The high ideal adsorbed solution theory C3H6/C2H4 selectivities (9.2, 10.6, and 15.1) and the breakthrough experiments results, including the high C2H4 purity (>99.9 %) and productivities (26.1, 73.1, and 101.0 L·kg-1), demonstrate its practical purification capability. Semi-empirical tight binding (xTB) quantum chemical calculations explain the mechanisms that differentiate C2H4 and C3H6 adsorption in JLU-MOF132. In addition, JLU-MOF132 also displays outstanding radioactive iodine adsorption performance, with an iodine uptake of 750 mg·g-1 in vapor and 153 mg·g-1 in cyclohexane solutions. Briefly, this work not only demonstrates the viability of employing the V-shaped ligand to increase the structural diversity of highly stable MOFs, but also enhances the application potential of MOFs in the fields of the MTO products separation and radioactive iodine adsorption.

Solvent-free CO2 cycloaddition by one- and two-dimensional sodium coordination polymers based on hydrazonic ligands

We successfully synthesized and characterized four new coordination polymers of sodium: sodium 4-hydroxy-3-{[2-(pyridine-4-carbonyl)hydrazinylidene]methyl}benzene-1-sulfonate (NaL4-Py), sodium 3-[(2-benzoylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaLPh), sodium 3-[(2-acetylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaLMe), and sodium 3-[(2-carbamoylhydrazinylidene)methyl]-4-hydroxybenzene-1-sulfonate (NaLNH2). These polymers were synthesized through a 1:1 condensation reaction of hydrazide derivatives with sodium salicylaldehyde-5-sulfonate monohydrate (NaSalSO3) and were thoroughly characterized using various analytical techniques. The compounds NaLMe and NaLPh, crystallized in the P 1‾ and P21/n space groups, respectively, forming one-dimensional polymers. On the other hand, NaLNH2 and NaL4-Py crystallized in the Cmca and P 1‾ space groups, respectively, forming two-dimensional coordination polymers. The coordination environment of the sodium cation differed among the compounds, with the imine nitrogen atom interfering in NaL4-Py and NaLPh. The sulfonate group exhibited various coordination modes, resulting in the different dimensionalities of the polymers. Compounds NaL4-Py and NaLPh acted as heterogeneous Lewis acid catalysts for the solvent-free cycloaddition reaction of epichlorohydrine and CO2 into valued cyclic carbonate. High selective conversion (68 %) of epichlorohydrin to cyclic carbonate was obtained at mild conditions, 60 °C and 1 bar CO2, after 24 h of reaction.

Tailoring O-Monodentate Adsorption of CO2 Initiates C-N Coupling for Efficient Urea Electrosynthesis with Ultrahigh Carbon Atom Economy.

The thermodynamically and kinetically sluggish electrocatalytic C-N coupling from CO2 and NO3- is inert to initially take place while typically occurring after CO2 protonation, which severely dwindles urea efficiency and carbon atom economy. Herein, we report a single O-philic adsorption strategy to facilitate initial C-N coupling of *OCO and subsequent protonation over dual-metal hetero-single-atoms in N2-Fe-(N-B)2-Cu-N2 coordination mode (FeN4/B2CuN2@NC), which greatly inhibits the formation of C-containing byproducts and facilitates urea electrosynthesis in an unprecedented C-selectivity of 97.1% with urea yield of 2072.5 μg h-1 mgcat.-1 and 71.9% faradaic efficiency, outperforming state-of-the-art electrodes. The carbon-directed antibonding interaction with Cu-B is elaborated to benefit single O-philic adsorption of CO2 rather than conventional C-end or bridging O,O-end adsorption modes, which can accelerate the kinetics of initiated C-N coupling and protonation. Theoretical results indicate that the O- monodentate adsorption pathway benefits the thermodynamics of the C-N coupling of *OCO with *NO2 and the protonation rate-determining step, which markedly inhibits CO2 direct protonation. This oriented strategy of manipulating reactant adsorption patterns to initiate a specific step is universal to moderate oxophilic transition metals and offers a kinetic-enhanced path for multiple conversion processes.

Deciphering the Impact of Nucleosides and Nucleotides on Copper Ion and Dopamine Coordination Dynamics.

The mode of coordination of copper(II) ions with dopamine (DA, L) in the binary, as well as ternary systems with Ado, AMP, ADP, and ATP (L') as second ligands, was studied with the use of experimental-potentiometric and spectroscopic (VIS, EPR, NMR, IR)-methods and computational-molecular modeling and DFT-studies. In the Cu(II)/DA system, depending on the pH value, the active centers of the ligand involved in the coordination with copper(II) ions changed from nitrogen and oxygen atoms (CuH(DA)3+, Cu(DA)2+), via nitrogen atoms (CuH2(DA)24+), to oxygen atoms at strongly alkaline pH (Cu(DA)22+). The introduction of L' into this system changed the mode of interaction of dopamine from oxygen atoms to the nitrogen atom in the hydroxocomplexes formed at high pH values. In the ternary systems, the ML'-L (non-covalent interaction) and ML'HxL, ML'L, and ML'L(OH)x species were found. In the Cu(II)/DA/AMP or ATP systems, mixed forms were formed up to a pH of around 9.0; above this pH, only Cu(II)/DA complexes occurred. In contrast to systems with AMP and ATP, ternary species with Ado and ADP occurred in the whole pH range at a high concentration, and moreover, binary complexes of Cu(II) ions with dopamine did not form in the detectable concentration.

Constructing Isoreticular Metal-Organic Frameworks by Silver-Carbon Bonds.

The incorporation of new coordinate bonds and the development of universal methods for new structures have always been of major interest in metal-organic framework (MOF) research. The poor reversibility makes metal-carbon (M-C) bonds a great challenge to adopt as linkages to construct crystalline MOFs. Herein, three isoreticular microcrystalline MOFs connected by silver-carbon (Ag-C) bonds are presented for the first time and named AgC-MOFs. Their structures contain a double coordination mode (σ and π) between Ag(I) and alkynyl. The three AgC-MOFs all exhibit three-dimensional (3D) frameworks with uniform one-dimensional (1D) hexagonal channels, and the pore width could be tuned from 1.1 to 1.8 nm. The construction of crystalline MOFs using poorly reversible Ag-C coordinate bonds extends the nexuses for the MOF structure and lights up more possibilities for the systematic design of MOFs.

Combining electron transfer, spin crossover, and redox properties in metal-organic frameworks

Hofmann coordination polymers (CPs) that couple the well-studied spin transition of the FeII central ion with electron-responsive ligands provide an innovative strategy toward multifunctional metal-organic frameworks (MOFs). Here, we developed a 2D planar network consisting of metal-cyanide-metal sheets in an unusual coordination mode, brought about by infinitely π-stacked redox-active bipyridinium derivatives as axial ligands. The obtained family of materials show vivid thermochromism attributed to electron transfer and/or electronic spin state change processes that can occur either independently or concomitantly. Importantly, the redox activity of the ligands within the structure leads to the quasi-reversible electrochemical reduction reaction on a spin-crossover complex at solid state. These observations have been confirmed via temperature-dependent single-crystal X-ray diffraction, magnetic measurements, Mössbauer, EPR, optical and vibrational spectroscopies as well as quantum chemical calculations.

Synthesis, structure, characterization and one pot catalytic activity of half-sandwich iridium(III) complexes

A series of stable mononuclear half-sandwich iridium(III) complexes of the general formula [(η5-C5Me5)Ir(L)Cl](BPh4) has been synthesized in dry methanol using different imino pyridine ligands (L1–L6) and [(η5-C5Me5)2Ir2(µ-Cl)2Cl2] in a 2:1 molar ratio. All complexes were fully characterized by melting point, CHN analysis, FT-IR, UV–visible, 1H NMR, 13C NMR spectroscopy and mass spectrometry. The structure of complex 3 [(η5-C5Me5)Ir(L3)Cl](BPh4) was determined by single crystal X-ray structure analysis, showing a chelating coordination mode of the imino pyridine L3. One pot organic transformations of aldehyde to amide were carried out by complexes 1–6 in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate. The catalytic activity of complex 3 was found to be excellent, showing high conversion with catalytic turnover frequency up to 500.

Neutral guest binding by meso‑3,5-bis(trifluoromethyl)phenyl two-wall calix[4]pyrrole: N-oxide recognition features and unique acetonitrile binding mode

Two-wall calix[4]pyrroles bearing two aryl substituents at diametrically opposed meso-positions have been well explored toward the recognition and sensing of anionic substrates. However, their ability to form stable complexes with neutral guests remains underexplored. Herein, we report the heterocyclic N-oxides (such as pyridine N-oxide (PNO), 4-methylpyridine N-oxide (MPNO), and 4-phenylpyridine N-oxide (PPNO)) binding features of meso-3,5-bis(trifluoromethyl)phenyl two-wall calix[4]pyrrole 1. Single crystal X-ray diffraction analysis of the PNO complex of 1 revealed the formation of two types of closely resembled 1/1 complexes within the same crystal, wherein the calix[4]pyrrole core adopted a cone-like conformation and the PNO was bound to the cleft delineated by two aromatic walls adopting pseudo-edge-to-face (PETF) geometry. MPNO formed only one type of 1/1 complex with receptor 1 having PETF geometry in the solid state. Solution phase interaction of 1 with PNO, MPNO, and PPNO was investigated by 1H NMR spectroscopic titrations carried out in CD3CN. On the other hand, X-ray diffraction analysis of single crystals of 1, grown from CH3CN solution, unveiled the formation of a 1/2 host-acetonitrile solvate containing an unstable arrangement of CH3CN dimer displaying a unique CH3CN coordination mode in the solid state. Furthermore, a unique 1D supramolecular chain of CH3CN was stabilized within the narrow channel in the crystal lattice of 1•(CH3CN)2.

Cyanide Linkage Isomerization Induced by Cobalt Oxidation-State Changes at a Co-Fe Prussian-Blue Analogue/ZnO Interface.

Understanding the interfacial composition in heterostructures is crucial for tailoring heterogenous electrochemical and photoelectrochemical processes. This work aims to elucidate the structure of a series of Co-Fe Prussian blue analogue modified ZnO (PBA/ZnO) electrodes with interface-sensitive vibrational sum frequency generation (VSFG) spectroscopy. Our measurements revealed, for the first time, a cyanide linkage isomerism at the PBA/ZnO interface, when the composite is fabricated at elevated temperatures. In situ VSFG spectro-electrochemistry measurements correlate the CoII➝CoIII oxidation with the flip of the bridging CN ligand from Co-NC-Fe coordination mode to a Co-CN-Fe one. Photoluminescence measurements and X-ray photoelectron spectroscopy reveal that this unprecedented linkage isomerism originates from surface defects, which act as oxidation sites for the PBA. The presence of such surface defects is correlated with the fabrication temperature for PBA/ZnO. Thus, this contribution identifies the interplay between the surface states of the ZnO substrates and the chemical composition of PBA at the ZnO surface, suggesting an easily accessible approach to control the chemical composition of the interface.

Zinc-cluster-based MOF with super selective separation adsorption catalyzes direct chemical conversion of CO2 from quasi-polluted air

The CO2 in the atmosphere has a serious impact on the human living environment. Direct utilization of the discharged CO2 to produce useful chemicals is challenging due to the practical presence of mixed compositions and low concentrations for CO2. Metal-organic frameworks (MOFs) with high internal surface areas, porosity and open metal site potentially possess superior adsorption separation capacity for CO2 gas, and on this basis, it can be used as a catalyst to achieve efficient chemical conversion of CO2. We demonstrate the synthesis and characterization of MOF ([Zn4O(ntba)2]n, MOF 1, H3ntba=4,4',4''-nitrilotribenzoic acid) with excellent selective adsorption properties from quasi- polluted air (O2, N2, CO2, CH4) and as heterogeneous catalysts for direct efficient CO2 chemical conversion. Detailed structural analysis reveals show that zinc ions behave multiple open metal sites and two coordination modes in the polyhedral zinc clusters building unit forming a 3D porous network by polyhedral zinc clusters building unit. Thanks to its structural features, at the 273 K and 100kPa, due to the ideal specific surface area and porosity, MOF 1 have ideal adsorption-separation performance for CO2, its values of adsorption and separation ratio are 75.7 cm3g−1, 373(CO2/N2), 79(CO2/O2), 13(CO2/CH4), respectively. The cycloaddition catalytic reaction investigations show that MOF 1 can be employed as a highly efficient catalyst for converting CO2 with a yield of 78 %. The result of this experiment offers the potential to directly utilize low-concentration and mixed CO2 while avoiding the economic and environmental costs of obtaining purified CO2 feeds tocks.

Progress and Challenges of Monometallic Titanium Coordination Polymers.

The realm of titanium coordination polymer research is still in its nascent stages and presents a formidable challenge in the field of coordination chemistry. In recent decades, the focus has predominantly been on manipulating titanium reactions in solution, resulting in the synthesis of ≈60 targeted compounds. Despite the limited number of documented instances, these materials showcase a diverse array of structures, encompassing 1D chains, 2D layers, and 3D frameworks. This suggests potential for fine-tuning coordination modes and structural features in future investigations. Moreover, titanium coordination polymers not only exhibit photo-active and photo-responsive properties but also hold promise for various other significant applications. This article offers an exhaustive review tracing the evolution of titanium coordination polymer development while providing an update on recent advancements. The review encompasses a synopsis of reported synthetic strategies, methodologies, structural diversity, and associated applications. Additionally, it delves into critical issues that necessitate attention for future progressions and proposes potential avenues to effectively propel this research field forward at an accelerated pace.

Thermodynamic Studies of Complexes in Cu(II)/Uridine-5'-Diphosphoglucuronic Acid System.

A binary system of uridine-5'-diphosphoglucuronic acid with copper (II) ions was studied. Potentiometric studies in aqueous solutions using computer data analysis were carried out. The pH of dominance, the overall stability constants (logβ), and the equilibrium constants of the formation reaction (logKe) were determined for each complex compound formed in the studied system. Spectroscopic studies were carried out to determine the mode of coordination in the compounds studied. Cytotoxicity and metabolic activity tests of the compounds obtained showed an increase in the biological activity of the complexes tested against the free ligand. The current research may contribute to the knowledge of complex compounds of biomolecules found in the human body and may also contribute to the characterization of a group of complex compounds with potential anticancer properties.

Molecular structure regulation and herbicidal activity of dibutyltin aryloxyacetate complexes

Six dibutyltin aryloxyacetate complexes [(X-C6H4OCH2COO)(SnBu2)2(μ3O)(OMe)]2 (A1, B1), [(X-C6H4OCH2COO)2(SnBu2)2(μ3O)]2 (A2, B2), and [(X-C6H4OCH2COO)2SnBu2] (A3, B3) were synthesized and characterized by IR, NMR, HRMS, and TGA techniques. The molecular structure of complexes A1, A3 and B1-B3 was confirmed by single-crystal X-ray crystallography. Complexes A1, B1, A2, and B2 are dimeric carboxylate tetraorganodistannoxanes, displaying a "ladder-like" molecular arrangement. The aryloxyacetate ligands in A1 and B1 adopt a monodentate mode, while they function as bridging coordination ligands in A2 and B2. Complexes A3 and B3 represent dibutyltin carboxylates with crystallographically imposed two-fold symmetry, with the aryloxyacetate ligands adopting a bidentate mode. Aryloxyacetic acids demonstrate a propensity for assuming various coordination modes, leading to the formation of diverse molecular architectures in organotin carboxylates. In addition, complex B1 exhibits polymorphism. Echinochloa crus-galli and Portulaca oleracea L. were used as target organisms for herbicidal activity testing using a petri dish method. It was found that they have a significant inhibitory effect on weed roots and stems at 200 μmol/L, and the structure-activity relationship analysis revealed the important influence of substituent types and complex structures on their activity.