Carboxylate Oxygen Atoms Research Articles

Room‐Temperature Phosphorescence Hydrogel with Multiple Color Based on Salt‐Induced Aggregation

AbstractOrganic photoluminescent materials with room‐temperature phosphorescence (RTP) are of great interest, yet achieving RTP in hydrogels faces challenges due to water‐quenching effects. In this study, a straightforward method is presented to achieve RTP hydrogel using a self‐healing and salt‐hardening hydrogel. The hydrogel is synthesized by polymerizing acrylic acid (AA) with diethylenetriamine (DETA) as the dynamic crosslinker. The poly(acrylic acid)/DETA hydrogel could achieve an afterglow lasting 1.6 s after soaking with NaBr solution. The salt‐enhanced hydrophobic aggregation of the hydrogel network promotes the clustering of carboxyl groups and oxygen atoms, resulting in a rigid environment that suppresses nonradioactive transitions and leads to the manifestation of RTP. Additionally, the dynamic association of AA‐DETA allows the freeze‐dried hydrogel powder to be blended with various hydrophobic dyes, leading to a remodelable hydrogel with delayed emission of multiple colors. In general, by combining salt‐hardening property with self‐healing property together, a RTP hydrogel platform that can be facilely loaded with various organic dyes is proposed.

Structural identification, stability and combination mechanism of calcium-chelating wheat gluten peptides

Abstract In order to explore the structures and combination mechanism of wheat gluten peptides-calcium chelate (WOP-Ca) in depth, WOP-Ca were prepared by chelating wheat gluten peptides (WOP) with calcium. The yield of WOP-Ca was determined to be 51.2 ± 2.12 %, and it exhibited a calcium-chelating rate of 58.96 ± 1.38 %. The structural differences between WOP-Ca and WOP were characterized using various analytical techniques, and the results revealed that WOP-Ca and WOP differed in their microstructure, characteristic group absorption peaks, changes in electron cloud distribution, and thermal stability. WOP-Ca demonstrated remarkable stability and resistance to changes in pH, temperature, and in vitro digestion with gastric protease. After undergoing various treatments, the molecular weight distribution in each interval changed very little. Identification of the peptides in WOP-Ca was achieved by utilizing a mass spectrometer, and a total of 39 peptides were identified in WOP-Ca. Among these, 14 peptides with Score ≥ 30 and Coverage ≥ 20 showed bioavailability percentages exceeding 30 %, with half surpassing 50 %. The binding mode between the 14 peptides and Ca2+ was determined to be α linkage. The Ca–O bond lengths ranged from 2.40 to 3.20 Å, indicating the formation of structurally stable complexes. The carboxyl oxygen atoms played a crucial role in binding with Ca2+, with bond lengths ranging from 2.41 to 2.49 Å and 2.43 to 2.46 Å, respectively. The finding suggested that WOP-Ca prepared by chelation may be used as a calcium supplement that could serve as food additives, dietary nutrients, and pharmaceutical agents.

Characterization and Mechanism of a Novel Rice Protein Peptide (AHVGMSGEEPE) Calcium Chelate in Enhancing Calcium Absorption in Caco-2 Cells.

Rice protein peptides (RPP) are a potentially valuable source of high-quality calcium chelating properties. However, there is a lack of information regarding the calcium-absorption-promoting effect of RPP and its underlying mechanism. The present study adopted molecular docking methodologies to analyze the 10 most potent peptide segments from RPP. Results revealed that the peptide AHVGMSGEEPE (AHV) displayed optimal calcium binding properties (calcium-chelating capacity 55.69 ± 0.66 mg/g). Quantum chemistry analysis revealed that the AHV peptide effectively binds and forms stable complexes with calcium via the carbonyl oxygen atoms in valine at position 3 and the carbonyl of the C-terminal carboxyl group of glutamate at position 11. The spectral analysis results indicated that AHV may bind to calcium through carboxyl oxygen atoms, resulting in a transition from a smooth surface block-like structure to a dense granular structure. Furthermore, this study demonstrated that the 4 mmol/L AHV-Ca chelate (61.75 ± 13.23 μg/well) significantly increases calcium absorption compared to 1 mM CaCl2 (28.57 ± 8.59 μg/well) in the Caco-2 cell monolayer. In terms of mechanisms, the novel peptide-calcium chelate AHV-Ca derived from RPP exerts a cell-level effect by upregulating the expression of TRPV6 calcium-ion-channel-related genes and proteins (TRPV6 and Calbindin-D9k). This study provides a theoretical basis for developing functional foods with the AHV peptide as ingredients to improve calcium absorption.

Lithium and sodium 3-(3,4-di-hydroxy-phen-yl)propenoate hydrate.

Treatment of 3-(3,4-di-hydroxy-phen-yl)propenoic acid (caffeic acid or 3,4-di-hydroxy-cinnamic acid) with the alkali hydroxides MOH (M = Li, Na) in aqueous solution led to the formation of poly[aqua-[μ-3-(3,4-di-hydroxy-phen-yl)propenoato]lithium], [Li(C9H7O4)(H2O)]n, 1, and poly[aqua-[μ-3-(3,4-di-hydroxy-phen-yl)propenoato]sodium], [Na(C9H7O4)(H2O)]n, 2. The crystal structure of 1 consists of a lithium cation that is coordinated nearly tetra-hedrally by three carboxyl-ate oxygen atoms and a water mol-ecule. The carboxyl-ate groups adopt a μ3-κ3 O:O':O' coordination mode that leads to a chain-like catenation of Li cations and carboxyl-ate units parallel to the b axis. Moreover, the lithium carboxyl-ate chains are connected by hydrogen bonds between water mol-ecules attached to lithium and catechol OH groups. The crystal structure of 2 shows a sevenfold coordination of the sodium cation by one water mol-ecule, two monodentately binding carboxyl-ate groups and four oxygen atoms from two catechol groups. The coordination polyhedra are linked by face- and edge-sharing into chains extending parallel to the b axis. The chains are inter-linked by the bridging 3-(3,4-di-hydroxy-phen-yl)propenoate units and by inter-molecular hydrogen bonds to form the tri-periodic network.

The non-steroidal anti-inflammatory drugs based on Zinc(II) picoline complexes: Synthesis, characterization, and evaluation of antiproliferative effects against human breast adenocarcinoma MDA-MB-453 cells by inducing ROS-mediated apoptosis and down-regulating PI3K/AKT signaling pathway

This work aims to synthesize zinc(II) non-steroidal anti-inflammatory complexes and to evaluate their anticancer abilities on different cancer cell lines. In this context, four new zinc(II) complexes including the NSAIDs mefenamic acid or niflumic acid and picoline derivatives {[Zn2(μ-mef)3(3-pic)2] 1, [Zn3(μ-mef)6(2-pic)2] 2, [Zn3(μ-mef)6(4-pic)2] 3 and [Zn(nif)2(4-pic)2]} 4 were synthesized. The molecular structures were identified by elemental analysis, FT-IR, 1H NMR (complexes 2 and 3), UV–Vis, thermal analysis, and X-ray diffraction (complexes 1 and 4), indicating that one complex was mononuclear, one complex was binuclear, and two complexes were trinuclear. The deprotonated mefenamato ligands bind to the zinc(II) ion via carboxylate oxygen atoms and chelate in a bridging bidentate asymmetric form. The deprotonated niflumato ligand acts as a monodentate ligand. UV–Vis spectroscopy was used to assess the complexes' stability. The stoichiometry of the synthesized complexes was determined by 1H NMR and thermal studies. XTT assays showed that all complexes exhibited dose-dependent antiproliferative effects against breast cancer MCF-7 and MDA-MB-453 cells, colon cancer HT-29 cells, and lung cancer A549 cells. The highest cytotoxicity was exhibited by complex 3 against MDA-MB-453 cells with an IC50 value of 8.28 µM. The mechanistic studies performed by flow cytometry revealed that complex 3 exerted its in vitro anticancer activity against MDA-MB-43 cells by inducing apoptosis, increasing ROS production, and inhibiting the PI3K/AKT signaling pathway.

Synthesis and structure of trans-bis-(4-amino-3-nitro-benzoato-κO)bis-(4-amino-3-nitro-benzoic acid-κO)di-aqua-manganese(II) dihydrate.

The manganese title complex, [Mn(C7H5N2O4)2(C7H6N2O4)2(H2O)2]·2H2O, is one of the first 4-amino 3-nitro-benzoic acid (4 A3NBA) monoligand metal complexes to be synthesized. It crystallizes in the centrosymmetric monoclinic space group P21/n with the complex mol-ecules located on inversion centers. Four 4 A3NBA ligand mol-ecules are monodentately coordinated by the Mn2+ ion through the carb-oxy-lic oxygen atoms while the other two positions of the inner coordination sphere are occupied by water mol-ecules, giving rise to a distorted octa-hedron, and two water mol-ecules are in the outer coordination sphere. There are two intra-molecular hydrogen bonds in the complex mol-ecule. The first is of the common N-H⋯O=N type, while the second is a rarely occurring very strong hydrogen bond in which a common proton is shared by two uncoordinated oxygen atoms of neighboring carboxyl-ate groups. In the crystal, an intricate system of inter-molecular hydrogen bonds links the complex mol-ecules into a three-dimensional-network.

Water-soluble chiral coordination polymers of Li+, Na+, K+, and Ba2+ with an anionic iron(III) complex of a L-threonine derivative and a significant red shift of visible spectra with Al3+ salt.

Four salts of an anionic iron(III) bis-complex, [Fe(LL-thr)2]1-, were synthesized from water or methanol. H2LL-thr is a tridentate ligand derived from the L-threonine amino acid, and the cations used are Li+ (1), Na+ (2), K+ (3), and Ba2+ (4). Single-crystal X-ray diffraction showed that all the complexes are coordination polymers of different dimensionalities. The iron(III) complex binds to cations through its coordinated phenolate and non-coordinated carboxylate oxygen atoms. While Li+ forms a linear chain, all others have a pair of bridged cations intervening the iron(III) complexes. The 3D network of Ba2+ salt has a sizeable solvent-accessible space occupied by aquated chloride ions. The differences in circular dichroism (CD) spectra and significantly lower conductance values in water and methanol support partial retention of the polymeric nature in methanol. The visible spectra of 4 in methanol or water showed an ∼10 nm shift of the charge transfer bands from 3. However, the addition of Al3+ salt to 2 showed a significant colour shift. Further investigation confirmed that the colour shift is due to partial protonation of the complex with protons generated from salt hydrolysis. Most reports on visual aluminium detection consider aluminium's binding as the shift's source. The present results show that protonation due to hydrolysis of aluminium salt can skew the observation.

One Ni-MOF with gate-opening behavior for unprecedented separation of C2H2 from C2 hydrocarbons

The separation and production of highly pure C2H2 from C2H4 and C2H6 is an important task in petrochemical industry, but it is challenging to synthesize target porous materials with excellent separation properties. In this paper, we reported the construction of a novel Ni-MOF material [Ni3(F-tzba)2(bpy)3(F)2] (F-H2tzba = 2-F-4-(1H-tetrazol-5-yl) benzoic acid, bpy = 4,4′-bipyridine) by using mixed bpy and F-H2tzba coligands. Ni-MOF has a pore surface modified by carboxyl oxygen atoms, tetrazolyl nitrogen atoms and F sites to better bind to C2H2 molecules than C2H4 and C2H6. Ni-MOF displayed a unique gate-opening effect on C2H4 and C2H6 adsorption in the low-pressure region, leading to significantly high selectivity of C2H2/C2H4 and C2H2/C2H6. Breakthrough experiments proved that Ni-MOF could not only effectively separate C2H2 (≥98 % purity) from C2H2/C2H6 and C2H2/C2H4 binary mixtures but also unprecedentedly separate C2 trinary hydrocarbon mixtures.

Catalytic oxidation of thymol and carvacrol with Mn(II)-benzoylbenzoate-bipyridine complex

The primary focus of catalytic chemistry is the synthesis of valuable chemicals from cheaper and more abundant substrates. The main objective of catalytic processes is to achieve higher yields at affordable costs under environmentally friendly conditions. Under homogeneous conditions, the synthesized bimetallic Mn(II) complex with (2-benzoylbenzoic acid, bba) and N,N coordinated (2,2-bipyridine, bipy) ligands, [Mn2(μ1,3-(C6H5)CO(C6H4)COO)2(bipy)2].2ClO4 is shown to be an active catalyst for the oxidation of monoterpenes (thymol and carvacrol), using TBHP under mild reaction conditions. The structure of the complex was characterized by single-crystal X-ray diffraction. The six-coordinated Mn(II) centers bridge in a coordination pattern due to the monodentate bonding mode of the carboxylate oxygen atoms of benzoylbenzoate anion. The selectivity of the Mn-catalyst was measured to be 100 % for thymol and carvacrol to thymoquinone. A simple, effective and selective Mn(II)/TBHP/Monoterpene/CH3CN catalyst system was used for the oxidation of thymol (TOF = 2000 h−1, in 15 min) and carvacrol (TOF = 667 h−1, in 45 min.) into a valuable product, thymoquinone (TQ), in acetonitrile at 80 °C.

The scale inhibition mechanism of sodium humate on heat transfer surface: Insights from electrochemical experiments, quantum chemical calculations, and molecular dynamics simulation

The scale inhibition mechanism of sodium humate (HAS) on Calcium Carbinate (CaCO3) was investigated by experiments, quantum chemical calculations and molecular dynamics simulations. The changes of electrochemical impedance spectroscopy were analyzed by electrochemical methods at different concentrations (0, 10, 30, 50, 70, 100 mg/L) of HAS. The molecular structure of HAS was optimized by quantum chemical calculation, and the charge distribution, electrostatic potential distribution and frontier orbital energy of HAS were obtained. The interaction simulation system between HAS and the crystal planes of calcite was constructed based on molecular dynamics simulation. The interaction mechanism between specific functional groups in HAS and calcite crystal plane was analyzed. The results show that the capacitance arc and charge transfer resistance increase with the increase of HAS concentration in the range of 0–50 mg. However, In the concentration range of 50–100 mg, the capacitance arc and charge transfer resistance decrease with the increase of concentration. In the optimized structure of HAS, the oxygen atom on the carboxyl group is more negatively charged. There is a strong mutual attraction between HAS and calcite crystal plane. The primary functional group responsible for achieving scale inhibition is formed through the bonding between the carboxyl oxygen atom within its molecular structure and the calcium atom on the calcite crystal plane. The research in this paper provides a strong guidance for the treatment of scale and the development of scale inhibitors.

Synthesis, Structural Characterization and Photocatalytic CO2 Reduction Activity of a New Gd(III) Coordination Polymer with 6-Phenylpyridine-2-carboxylic acid and 4,4’-Bipyridine Ligands

A new Gd(III) coordination polymer, {[Gd(L1)3(H2O)2]∙L2}n (1) (HL1 = 6-phenylpyridine-2-carboxylic acid, L2 = 4,4’-bipyridine) was synthesized using 6-phenylpyridine-2-carboxylic acid, 4,4’-bipyridine, NaOH and GdCl3∙6H2O. The structure of Gd(III) coordination polymer has been characterized by IR and X-ray single crystal diffraction. The result of single crystal analysis indicates that fundamental unit of Gd(III) coordination polymer contains one Gd(III) ion, three L1 ligands, two coordinated water molecules and one uncoordinated 4,4’-bipyridine. In 1, the Gd(III) ion is eight-coordinated and surrounded by six O atoms from three L1 ligands and two O atoms from two coordinated water molecules, respectively. The complex 1 exhibits 1D chained structure by the bridging interactions of two carboxyl-oxygen atoms and O−H∙∙∙N hydrogen bonds interactions. The 1D chains are further connected by - stacking interactions to form 3D network architecture. The photocatalytic CO2 reduction activity of complex 1 has also been investigated. The complex 1 exhibits good CO2 reduction activity. With the increase of time, the yield of CO from 18.2 mmol/g in the first hour to 60.3 mmol/g in the third hour. And the CO selectivity has reached 100%. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A zinc coordination compound showing green photoluminescence

Abstract A novel three-dimensional coordination compound has been solvothermally synthesized based on a tetracarboxylate ligand H4L (H4L = 1,3,6,8-tetrakis(4-carboxylphenyl)pyrene), Zn2L(H2O)2·2DEF (1) (DEF = N,N′-diethylformamide). Each Zn ion is coordinated by four carboxylate oxygen atoms from four L4− ligands and one oxygen atom from a water molecule to provide a distorted square-pyramidal geometry. Pairs of adjacent Zn cations are bridged by four carboxylate groups of four different L4− ligands to generate a paddle-wheel [Zn2(COO)4(H2O)2] secondary building unit (SBU). Each SUB is further linked to four L4− ligands to give a three-dimensional framework with cds-type (CdSO4-type) topology. The crystal structure has been determined via single-crystal X-ray diffraction, and the compound was characterized by elemental and thermal analysis, infrared spectroscopy, powder X-ray diffraction, and solid-state photoluminescence measurements.

Synthesis and study of bismuth(III) oxalates precipitated from mineral acid solutions

Bismuth oxalates of the compositions BiOH(C2O4), Bi2(C2O4)3·6H2O, Bi2(C2O4)3·7H2O, and Bi2(C2O4)3·8H2O were obtained by precipitation from bismuth solutions in perchloric, nitric, and hydrochloric acids with addition of oxalic acid. Compound compositions were confirmed by X-ray powder diffraction and chemical analysis, IR and Raman spectroscopy, and thermogravimetry. It has been shown that in the composition of bismuth(III) oxalate hydrates Bi2(C2O4)3· х H2O bismuth cation is coordinated by the oxygen atoms of carboxyl groups of oxalate ions and water molecules in the same way, and compositions, taking into account the structural features, are described by the general formula {[Bi2(C2O4)3(H2O)4]∙( x -4)H2O} n . Conditions for the oxidative thermolysis of BiOH(C2O4) and Bi2(C2O4)3·7H2O to yield the tetragonal modification of bismuth oxide β-Bi2O3 were determined.

Aqueous Structure of Lanthanide-EDTA Coordination Complexes Determined by a Combined DFT/EXAFS Approach.

Sustainable production of rare earth elements (REEs) is critical for technologies needed for climate change mitigation, including wind turbines and electric vehicles. However, separation technologies currently used in REE production have large environmental footprints, necessitating more sustainable strategies. Aqueous, affinity-based separations are examples of such strategies. To make these technologies feasible, it is imperative to connect aqueous ligand structure to ligand selectivity for individual REEs. As a step toward this goal, we analyzed the extended X-ray absorption fine structure (EXAFS) of four lanthanides (La, Ce, Pr, and Nd) complexed by a common REE chelator, ethylenediaminetetraacetic acid (EDTA) to determine the aqueous-phase structure. Reference structures from density functional theory (DFT) were used to help fit the EXAFS spectra. We found that all four Ln-EDTA coordination complexes formed 9-coordinate structures with 6 coordinating atoms from EDTA (4 carboxyl oxygen atoms and 2 nitrogen atoms) and 3 oxygen atoms from water molecules. All EXAFS fits were of high quality (R-factor < 0.02) and showed decreasing average first-shell coordination distance across the series (2.62-2.57 Å from La-Nd), in agreement with DFT (2.65-2.56 Å from La-Nd). The insights determined herein will be useful in the development of ligands for sustainable rare earth elements (REE) separation technologies.

Synthesis, Structural Characterization, Hirschfeld Surface Analysis and Photocatalytic CO2 Reduction of Yb(III) Complex with 4-Aacetylphenoxyacetic Acid and 1,10-Phenanthroline Ligands

A new nine-coordinated Yb(III) complex [YbL3(Phen)] (1) (HL = 2-(4-acetylphenoxy)acetic acid (APA), Phen = 1,10-phenanthroline) was synthesized with 2-(4-acetylphenoxy)acetic acid, YbCl3.6H2O, NaOH and 1,10-phenanthroline as materials. Complex (1) was characterized by IR and X-ray single-crystal diffraction analysis. The results show that the Yb(III) ion is nine-coordinated with seven carboxylate oxygen atoms from five different deprotonated APA ligands and two nitrogen atoms from one Phen ligand. Complex (1) forms a 3D supramolecular framework through the - stacking interactions between the Phen aromatic rings. The hirschfeld surface analysis of complex (1) was also calculated. The CO2 photoconversion activity of complex (1) has been performed under UV-vis light irradiation. The complex (1) shows good photocatalytic activity with the yield of CO is closed to 146 mmol/g after three hours of UV-vis light irradiation, the CO selectivity has reached to 97.9%. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Zn(II) complexes with mefenamic acid: Synthesis, characterization, and anticancer activity

In this study, three Zn(II) complexes were synthesized by reacting Zn(CH3COO)2· 2H2O or Zn(ClO4)2· 6H2O with mefenamic acid in the presence of imidazole and pyridine-based co-ligands. The resulting complexes were [Zn(mef)2(imi)2]; (1), [Zn(mef)(py)3]· (ClO4); (2), and [Zn3(mef)6(apy)2]; (3), where mef represents deprotonated mefenamic acid/mefenamato, imi represents imidazole, py represents pyridine and apy represents 2-aminopyridine. Elemental analysis, spectroscopic techniques (FTIR, UV–Vis, 1H and 13C NMR, fluorescence), PXRD (1) and (3), thermal analysis (TG-DSC) (1) and (3), and single crystal X-ray crystallography were employed to characterize the complexes. The Zn(II) in (1) and (2) are in a distorted tetrahedral coordination environment. In (1), the Zn(II) is coordinated by two mefenamato ligands, each coordinating via a monodentate carboxylate oxygen atom and two nitrogens of the imidazole ligands. In (2), the Zn(II) is coordinated by one mefenamato and three pyridine ligands. Complex (3) is a trinuclear zinc complex in which the central Zn(II) is coordinated by six oxygen atoms from six bridging carboxylate groups of the mefenamato ligands. Three mefenamato ligands and a monodentate 2-aminopyridine ligand also coordinate to two terminal Zn(II) ions in a tetrahedral coordination environment in (3). The cytotoxicity of the complexes was evaluated using an MTT assay against MCF-7 (human breast cancer cell line). The complexes demonstrated dependent cell cytotoxicity, with (2) showing the highest anticancer activity.

Theoretical, in Vitro Antiproliferative, and in Silico Molecular Docking and Pharmacokinetics Studies of Heteroleptic Nickel(II) and Copper(II) Complexes of Thiosemicarbazone-Based Ligands and Pefloxacin.

Twelve new heteroleptic nickel(II) and copper(II) complexes of the type [M(L1-6 )(Pfx)2 ] (1-12), where L1-6 =2-benzylidenehydrazinecarbothioamide (L1 ), 2-benzylidene-N-methylhydrazinecarbothioamide (L2 ), 2-benzylidene-N-phenylhydrazinecarbothioamide (L3 ), 2-(4-methylbenzylidene)hydrazinecarbothioamide (L4 ), 2-(4-methylbenzylidene)-N-methylhydrazinecarbothioamide (L5 ) and 2-(4-methylbenzylidene)-N-phenylhydrazinecarbothioamide (L6 ), Pfx=pefloxacin and M=Ni(II) or Cu(II) have been synthesised, and their structures were confirmed by different spectral techniques. The spectral data and density functional theory (DFT) calculations supported the bonding of pefloxacin drug molecule via one of the carboxylate oxygen atoms and the pyridone oxygen atom, and the thiosemicarbazone ligand via the imine nitrogen and the thione sulfur atoms with the metal(II) ion, forming distorted octahedral geometry. In vitro antiproliferative activity of the synthesized complexes was evaluated against three human breast cancer (T47D, estrogen negative (MDA-MB-231) and estrogen positive (MCF-7)) as well as non-tumorigenic human breast epithelial (MCF-10a) cell lines, which showed the higher activity for the copper(II) complexes. The interaction of the synthesized complexes with an oncogenic protein H-ras (121 p) was explored by in silico molecular docking studies. Further, in silico pharmacokinetics and ADMET parameters were also analysed to predict the drug-likeness as well as non-toxic and non-carcinogenic behavior, and safe oral administration of the complexes.

Theoretical, antioxidant, antidiabetic and in silico molecular docking and pharmacokinetics studies of heteroleptic oxovanadium(IV) complexes of thiosemicarbazone-based ligands and diclofenac

A series of new heteroleptic oxovanadium(IV) complexes with the general formula [VOL1–6(Dcf)] (1–6), where L1−6 = thiosemicarbazone (TSC)-based ligands and Dcf = diclofenac have been synthesized and characterized. The spectral studies along with the density functional theory calculations evidenced the distorted square-pyramidal geometry around oxovanadium(IV) ion through imine nitrogen and thione sulfur atoms of TSC moiety, and two asymmetric carboxylate oxygen atoms of diclofenac drug. The complexes were evaluated for in vitro antioxidant activity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) and superoxide radical scavenging assays with respect to the standard antioxidant drugs butylated hydroxyanisole (BHA) and rutin. The in vitro antidiabetic activity of the complexes was tested with enzymes such as α-amylase, α-glucosidase and glucose-6-phosphatase. The complexes containing methyl substituent showed higher activity than that containing the nitro substituent due to the electron-donating effect of methyl group. The in silico molecular docking studies of the oxovanadium(IV) complexes with α-amylase and α-glucosidase enzymes showed strong interaction via hydrogen bonding and hydrophobic interactions. The dynamic behavior of the proposed complexes was analyzed by molecular dynamics (MDs) simulations, which revealed the stability of docked structures with α-amylase and α-glucosidase enzymes. The in silico physicochemical and pharmacokinetics parameters, such as Lipinski’s ‘rule of five’, Veber’s rule and absorption, distribution, metabolism and excretion (ADME) properties predicted non-toxic, non-carcinogenic and safe oral administration of the synthesized complexes. Communicated by Ramaswamy H. Sarma

Copper(II) and Platinum(II) Naproxenates: Insights on Synthesis, Characterization and Evaluation of Their Antiproliferative Activities

The growth of antibiotic resistance is a matter of worldwide concern. In parallel, cancer remains one of the main causes of death. In the search for new and improved antiproliferative agents, one of the strategies is the combination of bioactive ligands and metals that are already consolidated in the synthesis of metallopharmaceutical agents. Thus, this work deals with the synthesis, characterization, and study of naproxen (Nap)-based complexes of copper(II) and platinum(II) as antiproliferative agents. The copper complex (Cu–Nap) presents a binuclear paddle-wheel structure in a 1 Cu:2 Nap:1 H2O molar composition, in which Cu(II) is bonded to the carboxylate oxygens from naproxenate in a bidentate bridging mode. The platinum complex (Pt–Nap) was identified as the square planar cis-[Pt(Nap)2(DMSO)2] isomer, in which Pt(II) is bonded to the carboxylate oxygen atom of Nap in a monodentate fashion. Both complexes were inactive against the Gram-positive and Gram-negative bacterial strains assessed. Pt–Nap presented low cytostatic behavior over a set of tumor cells, but good viability for normal cells, while Cu–Nap was cytotoxic against all cells, with a cytocidal activity against glioma tumor cells.

Open-Cage Fullerene as a Macrocyclic Ligand for Na, Pt, and Rh Metal Complexes.

An open-cage [60]fullerene derivative was prepared through Malaprade oxidation of a vicinal triol moiety as the key step. Above the 17-membered orifice, there is one carboxyl group. Three ketone carbonyl groups and one lactone carbonyl group are located on the rim of the orifice. The carboxylic and carbonyl oxygen atoms around the orifice act as strong polydentate ligands for a sodium ion. These oxygen atoms also react with [Rh(CO)2Cl]2 to form various isomeric rhodium complexes with comparable stability. The fullerene C═C bond on the rim of the orifice forms a stable platinum complex when treated with Pt(PPh3)4. Single crystal X-ray diffraction data reveal that one of the carboxylic oxygen atoms above the orifice forms a H-bond with the water molecule trapped in the cage.