Tetrahedral Complexes Research Articles

Intense Red Fluorescence From Surface Traps in BaSO4:V5+, Eu3+ and Its Applications.

BaSO4:V5+ synthesized at 1000°C in air exhibits an intense emission band peaking at 495 nm from surface traps assisted by atmospheric oxygen on excitation at 350 nm due to charge transfer from O2- to V5+ in the (VO4)3- tetrahedral complex. BaSO4:Eu synthesized under similar conditions exhibits both Eu2+ (375 nm) and Eu3+ (619 nm) fluorescence. Vanadium codoping quenches the Eu2+ fluorescence but enhances the Eu3+ fluorescence in BaSO4:V, Eu due to charge compensation. However, Eu codoping quenches the vanadium fluorescence by diffusion of vanadium into the crystal, and V2O5 also serves as a flux enhancing Eu3+ doping efficiency in BaSO4 lattice. The 619nm Eu3+ PL emission intensity in BaSO4:V5+, Eu3+ is comparable to 592nm emission from commercial (Y,Gd) BO3:Eu3+. However, V5+ emission shows strong thermal quenching, while Eu3+ emission shows little thermal quenching up to 210°C, making BaSO4:V5+, Eu3+ a promising new red phosphor for improving the color rendering of blue light-based white LED. The ratio of Eu3+ to V5+ fluorescence increases with excitation temperature (30°C°C-180°C) enabling BaSO4:V5+, Eu3+ to be used as a non-contact luminescence thermometer.

Cu(II) complexes of 2-methoxy-5-sulfamoylbenzoic acid and 2-aminopyridine derivatives: Synthesis, characterization and antimicrobial activity

Three novel mixed ligand Cu(II) complexes {[Cu(sba)2(X)2].2H2O, X = 2a3NO24mp for 1, 2a5Clp for 2, 2a5NO2p for 3} obtained from 2-methoxy-5-sulfamoylbenzoic acid (Hsba) with 2-amino-3-nitro-4-methylpyridine (2a3NO24mp), 2-amino-5-chloropyridine (2a5Clp) and 2-amino-5-nitropyridine (2a5NO2p), respectively, have been prepared. The structures of 1-3 FT-IR, AAS, UV, molar conductivity, magnetic susceptibility, and charge balance as suggested by previous studies have been characterized. According to spectroscopic findings, the structures of 1-3 can be postulated as tetrahedral complexes. Furthermore, all compounds have been screened for their antibacterial and antifungal activities against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (NRRL B-767), Bacillus subtilis, Escherichia coli (ATCC25922) and Listeria monocytogenes (ATCC 7644) bacteria and Candida albicans (F89) yeast. The outcomes are contrasted with those of the control substances (Fluconazole as antifungal and Cefepime, Levofloxacin, and Vancomycin as antibacterial agents). The best activity values of the compounds are Cu(Ac)2.2H2O for S. aureus bacteria, 2a5NO2p for E. coli bacteria, 2 for P. aeruginoa bacteria, Hsba, 2a3NO24mp and 2a5NO2p for L. monocytogenes bacteria, Cu(Ac)2.2H2O, 2a3NO24mp, 2a5Clp, 2a5NO2p and 2 for E. faecalis bacteria, all compounds (except 3) for B. subtilis bacteria, and 2a5NO2p and 1 were observed for C. albicans yeast.

Synthesis, calf-thymus DNA interaction with trimethyl-/triphenyl-tin(IV) derivatives of ɑ-lipoic acid and their mixed ligand complexes with N-donor (1,10-phenanthroline/2,2′-bipyridyl/benzimidazole)

The mixed ligand complexes of trimethyl-/triphenyl-tin(IV) derivatives of ɑ-lipoic acid (HLA), viz. R3Sn(LA) {R = Me (1), and Ph (2)}with 1,10-phenanthroline (phen), viz. [Me3Sn(LA).phen] (3), 2,2′-bipyridyl, viz. [Ph3Sn(LA).by] (4) and benzimidazole (bz), viz. [R3Sn(LA).bz] {R = Me (5), and Ph (6)} were synthesised and satisfactorily characterized by analytical and spectroscopic techniques, especially FT-IR, NMR (1H, 13C, and 119Sn NMR) spectroscopy and ESI-MS spectrometry. The ∠C-Sn-C bond angle calculated by optimization of their gas-phase geometry revealed that complexes (1) and (2) have distorted tetrahedral geometry and complexes (3) and (4) exhibited distorted octahedral geometry while complexes (5) and (6) exhibited trigonal bipyramidal environment around the tin, which agreed with the data obtained from NMR. Spectroscopic titrations (UV–visible absorption, fluorescence titration, and circular dichroism) were performed to ascertain the binding mode of the complex with calf thymus DNA (CT-DNA). The obtained values of Kb in the order of 105 M−1 suggested partial intercalative interactions of complexes with DNA grooves/base pairs. The complexes efficiently cleaved plasmid DNA (pBR322) into supercoiled (Form I), nicked/circular (From II), and linear structure (Form III). The fascinating biophysical data suggests the potential of these complexes as anticancer agents.

Reactivity of Zinc Fingers in Oxidizing Environments: Insight from Molecular Models Through Activation Strain Analysis.

The reactivity of Zn2+ tetrahedral complexes with H2O2 was investigated in silico, as a first step in their disruption process. The substrates were chosen to represent the cores of three different zinc finger protein motifs, i. e., a Zn2+ ion coordinated to four cysteines (CCCC), to three cysteines and one histidine (CCCH), and to two cysteines and two histidines (CCHH). The cysteine and histidine ligands were further simplified to methyl thiolate and imidazole, respectively. H2O2 was chosen as an oxidizing agent due to its biological role as a metabolic product and species involved in signaling processes. The mechanism of oxidation of a coordinated cysteinate to sulfenate-κS and the trends for the different substrates were rationalized through activation strain analysis and energy decomposition analysis in the framework of scalar relativistic Density Functional Theory (DFT) calculations at ZORA-M06/TZ2P ae // ZORA-BLYP-D3(BJ)/TZ2P. CCCC is oxidized most easily, an outcome explained considering both electrostatic and orbital interactions. The isomerization to sulfenate-κO was attempted to assess whether this step may affect the ligand dissociation; however, it was found to introduce a kinetic barrier without improving the energetics of the dissociation. Lastly, ligand exchange with free thiolates and selenolates was investigated as a trigger for ligand dissociation, possibly leading to metal ejection; molecular docking simulations also support this hypothesis.

Blue‐Emissive Fluorescent Zinc(II) Complexes with Bis(imidazo[1,5‐a]pyridine)methane Ligands

Three bis(imidazo[1,5‐a]pyridine)methane derivatives (bis(1‐methylimidazo[1,5‐a]pyridin‐3‐yl)methane, LH; 3,3'‐(ethane‐1,1‐diyl)bis(1‐methylimidazo[1,5‐a]pyridine) LMe; 3,3'‐(2‐phenylethane‐1,1‐diyl)bis(1‐methylimidazo[1,5‐a]pyridine), LBz) have been synthesized, and fully characterized in solution (1H and 13C NMR spectra) and in the solid state (X‐ray). In particular, LH has been prepared in high yield (75%) under very mild conditions (water, 60°C), offering an alternative route to those reported in the literature. LMe and LBz have been obtained from LH by functionalization of the methylene bridge. The bis(imidazo[1,5‐a]pyridine)methane compounds have been coordinated to a zinc(II) center, leading to tetrahedral complexes of general formula [Zn(LR)2](ClO4)2 (R = H, Me, Bz), which showed a bright fluorescent emission with (x,y) color coordinates very close to standard blue. TD‐DFT have been employed to describe the Frontier Molecular Orbitals (FMOs) participating in electronic transitions, highlighting the main transition as 1(π‐π*) transition in the bis(imidazo[1,5‐a]pyridine)methane and a mixed intra‐ligand (1ILT) and ligand‐to‐ligand (1LLT) transition in the complexes.

Impact on activation energy with elevating calcination temperature of barium bismuth ferrite nanocomposite

Barium Bismuth Ferrite nanoparticles having the general formula Ba1-xBixFeO3 were successfully made by the sol-gel system, using nitrates as the fundamental material. Tartaric acid and polyvinyl alcohol were used as chelating agents. The synthesized nanoparticle powder was sintered at 650 ̊C and 750 ̊C for 3 h. Filtering with dilute nitric acid and distilled water is used to remove the impurities. The structural, optical, and dielectric properties were determined at room temperature. Using X-ray diffraction (XRD) analysis, structure, lattice parameter, microstrain, and dislocation density were calculated. Using the Scherrer equation, the peak's crystalline size was ascertained. In FTIR, the vibrational modes of the octahedral and tetrahedral metal complexes in the sample have been studied using the wavenumber in this range. The synthesized nanocomposite contains morphological features, such as interconnecting agglomerates with spherical, irregular, or non-uniform elongated shapes, as demonstrated by SEM images. The activation energy for relaxation and activation energy for conduction was measured from the Cole-Cole plot and the AC conductivity versus frequency plot respectively. The determined activation energies from the two investigations were relatively close to one another. The Barium Bismuth Ferrite nanoparticles samples at room temperature indicate that the samples have implicit candidates for information storage devices for spintronic devices. In the high frequency range, all samples depending upon the temperature demonstrate excellent dielectric behaviour and small dielectric loss, and with stable dielectric constant, these samples make their prospective for the practical application in spintronic devices the main goal of this work.

Synergistic exploration of antimicrobial potency, cytotoxicity, and molecular mechanisms: A tripartite investigation integrating in vitro, in vivo, and in silico approaches for pyrimidine‐based metal (II) complexes

We synthesized and characterized bioactive metal (II) complexes from a pyrimidine‐based Schiff base ligand, 4‐[2‐(4‐chlorobenzylidene) hydrazinyl]‐7H‐pyrrolo[2,3‐d]pyrimidine. Through thorough elemental analysis and various physicochemical techniques, we characterized both the ligand and its Zn(II), Cd(II), and Hg(II) complexes. Coordination of the metallic ion was established via nitrogen atoms from the ligand's pyrrolo and pyrimidine rings, yielding tetrahedral complexes of the type [M(PPHpCB)2]. These complexes are identified as non‐electrolytes due to their low molar conductance. Furthermore, we investigated the coordination behavior of the pyrimidine‐based Schiff base ligand (HPPHpCB) with metal ions through comprehensive spectroscopic analysis. 1H NMR spectral data showed bonding between HPPHpCB and metal ions, while UV spectra confirmed intra‐ligand and ligand‐to‐metal charge transfer transitions, indicating coordination through nitrogen atoms. The determination of tetrahedral geometry for metal complexes confirmed their diamagnetic properties. Analysis using 13C NMR and electrospray ionization mass spectra (ESI‐MS) revealed variations in chemical shifts, confirming successful complex formation and elucidating structural modifications, electronic interactions, and metal–ligand coordination modes. Moreover, evaluation of in vitro antimicrobial activities using the minimum inhibitory concentration (MIC) approach revealed significant antibacterial and antifungal activities for Hg(II) and Cd(II) complexes, respectively. The Hg(II) complex displayed superior antioxidant activity, while Zn(II) and Cd(II) complexes also demonstrated considerable potential. In vivo, cytotoxicity assessments against Artemia salina provided insights into the cytotoxic properties of ligands and metal complexes. Computational techniques suggested their potential in combating infectious ailments. Overall, our study establishes the synthesis, characterization, and multifaceted biological activities of metal (II) complexes derived from the pyrimidine‐based Schiff base ligand, highlighting their promising role in combating various infectious diseases.

9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of 8-quinolinolato ligands with heavy-atoms substituents: Synthesis, fluorescence and application in OLED devices

This work describes the synthesis and characterisation of new tetrahedral boron complexes, incorporating bromine- or iodine-substituted 8-quinolinolato chelate chromophores connected to 9-borafluoren-9-yl or diphenylboron orthogonal fragments. The molecular features and photophysical properties of these complexes are analysed in both solution and solid state. Steady-state photophysical studies reveal photoluminescence quantum yields (Φf) ranging from 0.02 to 0.15 and prompt fluorescence (PF) lifetimes (τf) between 2 and 16 ns. Time-resolved photophysical experiments show the presence of delayed fluorescence (DF) and phosphorescence at both 77 K and room temperature. The DF intensity increases with a rise in temperature. This variation is ascribed to an enhancement in the intersystem crossing (ISC) process promoted by the bromine or iodine heavy-atom effect. Investigations into the dependence of DF intensity relative to the excitation dose indicate emissions stemming either from Triplet-Triplet Annihilation (TTA), Thermally Activated Delayed Fluorescence (TADF), or a combination of these competing mechanisms. The effect is related to the size and number of heavy-atom substituents in each boron complex. A study of the DF emission intensity as a function of the excitation dose reveals that diiodo-substituted 8-quinolinolato boron complexes, whether rigid or flexible, display TADF emission. Rigid 5,7-dibromo- and 5-chloro-7-iodo-substituted 8-quinolinolato complexes exhibit a combined TADF-TTA mechanism, whereas the other complexes predominantly demonstrate pure TTA emission. DFT and TDDFT calculations showed that the ground state structures reproduced the experimental geometries and only small increases in bond lengths were observed in the excited state geometries. The low energy absorption bands displayed mainly intra-ligand π→π* (8-quinolinato) character. The fluorescence emission energies were well reproduced, while the singlet-triplet energy gaps were relatively high and spin-orbit coupling was relevant for complexes with heavy-atoms. Ultimately, organic light-emitting diodes (OLEDs) are fabricated using the most luminescent boron complexes. The best OLED is obtained when using complex 3a, which displays green electroluminescence (EL) (λEL = 502 nm) with maximum external quantum efficiency (EQEmax) of 2.5% and maximum luminance (Lmax) of 2200 cd m−2.

Calcination temperature dependence of tri-magnetic nanoferrite Ni0.33Cu0.33Zn0.33Fe2O4: Structural, morphological, and magnetic properties

The calcination temperature plays a pivotal role in determining the physical and magnetic properties of ferrite nanoparticles, influencing their performance and applicability in various applications. In this study, Ni0.33Cu0.33Zn0.33Fe2O4 nano ferrites were produced using the coprecipitation method and subsequently calcined at different temperatures, specifically 500 °C, 550 °C, 600 °C, 650 °C, and 700 °C. The X-ray diffraction analysis confirmed the presence of cubic spinel ferrite phase (Fd-3m) and revealed an increase in crystallite size from 12.84 to 20.19 nm as the calcination temperature increased from 500 °C to 700 °C. X-ray photoelectron spectroscopy analysis provided insights into chemical oxidation states. Scanning electron microscopy and transmission electron microscopy images revealed that at higher calcination temperatures, nanoparticles tend to aggregate. This aggregation is associated with an observable rise in particle size, increasing from 18.16 to 29.11 nm for nanoparticles calcined at 500 °C and 700 °C, respectively. Energy-dispersive X-ray confirmed pure elemental compositions. Fourier transform infrared spectroscopy identified red and blue shifts in wavenumbers corresponding to tetrahedral and octahedral group complexes, respectively. Nanoparticles calcined at 700 °C exhibited the highest saturation magnetization (62.642 emu/g) and coercivity (75.27 G), as revealed from the vibrating sample magnetometry analysis. Upon increasing the calcination temperature from 500 °C to 700 °C, the ferromagnetic contribution was improved from 24.26% to 98.64% along with a reduction in superparamagnetic contribution from 75.74% to 1.34%, respectively. The electron paramagnetic resonance (EPR) study showed an increase in the values of g and ΔHpp with the rise in calcination temperature. This observation suggests an enhancement in dipole–dipole interactions. Furthermore, a linear relationship was discovered between the g factor and crystallite size, inducting the formation of single domain. Finally, altering the calcination temperature adjusted the physical and magnetic properties of Ni0.33Cu0.33Zn0.33Fe2O4 nanoparticles. This adjustment indicates their potential for versatile applications, particularly in hyperthermia treatment and as T2 contrast agents in magnetic resonance imaging.

Metal‐triggered supramolecular hydrogels based on bipyridine ligand possessing hydrazine moieties with metal ions

AbstractBipyridine‐based gelator 1 having two D‐alanine units was prepared, and its gelation ability was evaluated in the presence of Co(NO3)2 and AgNO3 in water. Gelator 1 could gelate H2O in the presence of Co(NO3)2 or AgNO3 (1.0 equiv.) in water. Gelator 1 formed a 2:1 (1:Co2+) octahedral complex with Co2+, whereas it formed a 2:1 (1:Ag+) tetrahedral complex with Ag+. The metallosupramolecular hydrogel with Co2+ assembled into a left‐handed helical fiber, whereas that with Ag+ assembled into a nanorod structure. 1H NMR and FTIR analyses revealed that π–π stacking and intermolecular hydrogen bonds acted as the driving force for the formation of the supramolecular nanoarchitectures. Furthermore, to characterize the viscoelastic properties of hydrogels, rheology experiments were conducted at 25°C, including time, strain, and frequency sweeps.

Mammalian Cell Cytotoxicity, Antibacterial Activity and the Properties of Methylenebis(Hydroxybenzoic Acid) and Its Related Zinc(II) Complex

Formaldehyde, sulfuric acid and salicylic acid were combined to create a 3,3′-methylenebis(2-hydroxybenzoic acid) (MHB) ligand, which was subsequently permitted to bind with zinc(II) ions. The ligand and its zinc(II) complex (Zn–MHB) have been described by a combination of elemental analyses, spectral analyses (UV–Vis, IR, MS and NMR), XRD, TEM, as well as TGA measurement. The ligand has been suggested to coordinate to the zinc center in a tetradentate manner forming the binuclear tetrahedral complex. An X-ray analysis indicated a considerable difference between MHB (crystalline) and Zn–MHB (amorphous). The UV–Vis spectra were used to determine the optical properties such as bandgap, refractive index, optical conductivity and penetration depth. The possibility of employing the samples for optoelectronic applications was indicated from the band gap values which underlie the range of semiconductors. TEM revealed the spherical shapes and mutation of ligand particles into the nano-scale by complexation. The antimicrobial potential of the MHB towards Gram-positive and Gram-negative bacterial growths has been investigated. The results suggested that it would be possible to employ MHB to prevent bacterial development, particularly that of salmonella typhimurium. The cytotoxicity of the MHB was assessed against two types of mammalian cells: VERO (the kidney of an African green monkey) and HFB4 (human skin melanocytes). Lower sensitivity was observed in VERO cells.

Structure of polyethylene glycol/water mixtures as a separation medium of aqueous two-phase extraction systems studied by equilibrium analysis of thiocyanato complexation of Cobalt(II)

Aqueous two-phase systems (ATPS) utilizing polyethylene glycol (PEG) have been successfully used for the separation of various organic and inorganic compounds as an environmentally benign extraction method. However, a fundamental understanding of the role of the hydration structures around PEG chains in solute partitioning in ATPS remains elusive although it has been considered that PEG molecules are involved in separation. In the present work, the equilibria of Co(II) thiocyanate complexation reaction in aqueous PEG solutions were studied by spectrophotometry with varying ethylene oxide chain length and concentration of PEG. From the formation constants of the tetrahedral and octahedral Co(II) thiocyanate complexes obtained, a microheterogeneous structure consisting of pseudo phases formed by hydration of ethylene oxide (EO) chain and terminal hydroxyl (OH) groups in the PEG molecule in addition to the bulk water phase was estimated. It was revealed that the formation of tetrahedral Co(NCS)42− complex proceeds in the EO pseudo phase by the involvement of hydrophobic ethylene groups, while the OH phase and the bulk phase inhibit the progress of the reaction. This indicates that Co(NCS)42− is stable in hydrophobic hydration structure of water around the EO moiety. The EO phase imparts hydrophobicity to aqueous PEG solutions and plays a predominant role in partition of solute molecules in PEG-based ATPS.

Synthesis and characterization of cis and trans cobalt(II) nalidixate complexes having a 1-(4-chlorophenyl)-3-(pyridin-4-ylmethyl)urea ligand.

The synthesis and characterization of specific cis- and trans-isomers of a cobalt(II) bis-nalidixate complex with a pyridine-based urea, 1-(4-chlorophenyl)-3-(pyridin-4-ylmethyl)urea (L), ligand are reported. The two isomers, cis-[Co(L)2(NALD)2]·0.5DMF·H2O and trans-[Co(L)2(NALD)2]·2DMF·2H2O (the nalidixate anion is abbreviated to NALD) were prepared by anion-guided synthesis. When cobalt(II) chloride was used as one of the reactants, the reaction yielded the trans-isomer under ambient reaction conditions. Whereas a reaction using cobalt(II) nitrate provided only the cis-isomer when the reaction was continued for a prolonged time. On the other hand, the cis-isomer was converted to the trans-isomer in solution upon treatment with chloride ions. The chloride-assisted formation of the trans-isomer was investigated by a UV-visible study, and it passed through a bond reorganization by forming a tetrahedral intermediate complex. A DFT calculation was carried out to show the difference in energy between the isomers as well as the energy of a plausible tetrahedral cobalt complex. The aggregation behavior of the cis-isomer in different solvents was investigated, and solvent-dependent aggregation and a solvent-dependent Cotton effect were observed.

Supramolecular compounds assembled from the heteroleptic tetrahedral complex [{CpMo(CO)2}2(μ,η2-AsSb)] and metal salts.

The reaction of the tetrahedral complex [{CpMo(CO)2}2(μ,η2-AsSb)] with CuI and AgI salts is presented which gives unprecedented neutral and cationic supramolecular aggregates featuring mixed As/Sb-donor molecules as ligands/linkers between metal ions.

Metamagnetism and canted antiferromagnetic ordering in two monomeric CoII complexes with 1-(2-pyrimidyl)piperazine. Hirshfeld surface analysis and theoretical studies.

Here we present the magnetic properties of two cobalt complexes formulated as: [Co(SCN)2(L)2] (1) and (H2L)2[Co(SCN)4]·H2O (2) (L = 1-(2-pyrimidyl)piperazine). The two compounds contain isolated tetrahedral CoII complexes with important intermolecular interactions that lead to the presence of a canted antiferromagnetic order below 11.5 and 10.0 K, with coercive fields at 2 K of 38 and 68 mT, respectively. Theoretical calculations have been used to explain this behaviour. Hirshfeld surface analysis shows the presence of strong intermolecular interactions in both compounds. The crystal geometries were used for geometry optimization using the DFT method. From the topological properties, electrostatic potential maps and molecular orbital analysis, information about the noncovalent interaction and chemical reactivity was obtained.

Dibenzoazepine hydrazine is a building block for N-alkene hybrid ligands: exploratory syntheses of complexes of Cu, Fe, and Li.

The new hydrazine 5H-dibenzo[b,f]azepin-5-amine (2) reacts with P- and Si-electrophiles via deprotonation to afford P(III)-, P(V)-, and TMS-hydrazides 3-8 and with carbonyl electrophiles via acid-free condensation to the N-substituted hydrazones 9-12 that are potential N-alkene ligands. While β-ketohydrazone 9 and α-dihydrazone 10 react with [Mes(Cu)]4, [Cu(NCCCH3)4]2PF6, and FeCl2(THF)1.5 to afford complexes devoid of alkene interaction, [Cu(OTf)]2·C6H6 reacts with the α-keto hydrazone 11 or with N,N dimethyl-hydrazone 12 to form the neutral dimeric Cu(I) complex 18 with bridging Cu(I)-alkene interactions or the tetrahedral cationic complex 19 in which 12 binds as a bidentate hydrazone-alkene ligand, respectively. The surprising stability of the alkene coordination in complexes 18 and 19 prevents substitutions with, e.g., PPh3.

Three new Zn (II)-based coordination polymers: Optical properties and dye degradation against RhB

Three newly developed coordination polymers (CPs), denoted as [Zn2(HL)(ptp)2]n(1), [Zn(HL)(bpz)·0.25H2O]n(2) and [Zn(HL)(bic)·H2O]n(3), have been synthesized using hydrothermal methods. These CPs are composed of zinc ions and specific ligands with 3-(4-carboxyphenoxy)-5-methylbenzoic acid (H3L); 3,5-bis(4-pyridyl)-1,2,4-triazolyl (ptp); 3,3ʹ,5,5ʹ-tetramethyl-4,4ʹ-bipyrazole (bpz) and 3,6-bis(imidazol-1-yl)-9H-carbazole (bic) which provide oxygen and nitrogen donor sites. The molecular structures of the CPs were determined through single X-ray diffraction analysis, revealing a tetrahedral geometry. The CPs 1–3 have distorted tetrahedral geometry. The layered structural progression, starting from the tetrahedral complex and moving towards 1D, 2D, and potentially 3D networks, showcases the intricacies and hierarchical nature of CP 1–3’s molecular architecture. An interesting property of these CPs is their semiconducting nature. They exhibit the ability to serve as photocatalysts, especially against organic pollutants such as Acid chrome blue (ACB), Methyl blue (MB), Methyl orange (MO), and Rhodamine B (RhB). Among the CPs, CP 1 demonstrates superior photocatalytic activity against RhB (RhB) at a concentration of 25 mg/L. This suggests that CP 1, when used in a quantity of 25 mg, exhibits enhanced efficiency in degrading RhB through photocatalysis. The optimal conditions, where 25 mg/L RhB and 25 mg of CP 1 are employed, result in the degradation of an impressive 97.51 % of RhB.

The feasibility of pyrite dissolution in the deep eutectic solvent ethaline: Experimental and theoretical study

Environmental concerns about the traditional gold extraction process, and the potential volume of encapsulated gold in sulfidic minerals i.e. pyrite, have motivated researchers to find effective, efficient and ecologically benign ways to expose the enclosed gold for improved extraction. Neoteric deep eutectic solvents (DESs) are an analogue of ionic liquids (ILs) which are gaining more attention as eco-friendly solvents. This study examined the viability of pyrite dissolution in a DES comprised of choline chloride (ChCl) and ethylene glycol (EG), called Ethaline. The pH of the ethaline solvent mixed with hydrogen peroxide oxidant, and different solid-to-liquid ratios were examined. Ethaline solution with pH 8 provided the desired condition at which EG is deprotonated to [C2H4O2]2−, a favourable ligand for Fe complexation and thus pyrite dissolution. A solid-to-liquid ratio of 1/20 was optimal and achieved 23.6% Fe extraction as an indication of pyrite dissolution. Density functional theory (DFT) was applied to determine which of the two ligands provided by ethaline (Cl– and/or [C2H4O2]2−) can form the most stable complex with Fe2+ and/or Fe3+. As a result, the tetrahedral complex [Fe(C2H4O2)2]− with the ligand [C2H4O2]2− through O-donor chelating with Fe3+ was found to be the most probable and stable complex. However, the ethaline solvent did not deliver adequate Fe extraction compared to commonly used reagents/solvents like mineral acids, to fully break down pyrite and expose any encapsulated gold.

Electronic Structure, Reactivity, And Some Magnetic Properties of Paramagnetic Tetrahedral Di Nuclear Cobaltous Complexes. (Theoretical Study)

The tetrahedral paramagnetic di-cobaltous complex is an important class of coordination compounds that have many applications in various fields such as catalysis, single molecular magnet SMM, and spintronics[1], using BP86 functional[24] with def2-TZVP[25], basis set, while the broken symmetry theoretical method was conducted by B3LYP functional, the reactivity of the synthesized paramagnetic di cobaltous [Co2LI2OH] + complex[2] can be enhanced by the lowering HOMO-LUMO gap effect of oxo bridging ligand instead hydroxo ligand, also from the different theoretical approaches for calculating the exchange coupling constant to tetrahedral paramagnetic di-cobaltous complex, we found that the best approach was achieved by Noodlman treatment[3], also for such chemical environments the best calculated spin population was generated by Mulliken spin analysis.

Directing Molecular Weaving of Covalent Organic Frameworks and Their Dimensionality by Angular Control.

Although reticular chemistry has commonly utilized mutually embracing tetrahedral metal complexes as crossing points to generate three-dimensional molecularly woven structures, weaving in two dimensions remains largely unexplored. We report a new strategy to access 2D woven COFs by controlling the angle of the usually linear linker, resulting in the successful synthesis of a 2D woven pattern based on chain-link fence. The synthesis was accomplished by linking aldehyde-functionalized copper(I) bisphenanthroline complexes with bent 4,4'-oxydianiline building units. This results in the formation of a crystalline solid, termed COF-523-Cu, whose structure was characterized by spectroscopic techniques and electron and X-ray diffraction techniques to reveal a molecularly woven, twofold-interpenetrated chain-link fence. The present work significantly advances the concept of molecular weaving and its practice in the design of complex chemical structures.