Derivative Ligands Research Articles

Synthesis, Characterization and Antibacterial activity of Benzimidazole Derivatives and their Cu (ii),Ni (ii) and Co (ii) complexes

Benzimidazole is one of the privileged nitrogen-containing heterocyclic compounds, which is found in many bioactive compounds, benzimidazole and its derivatives have evolved as an important heterocyclic system due to their potency in a wide range of biologically active compounds like anthelmintic, antibacterial, antifungals, anti-inflammatory, antiviral, and so on. Derivatives of 1-arylsulfonylbenzimidazole and their respective Cu (II), Ni (II) and Co (II) complexes were successfully synthesized. The structures of all the synthesized ligands were confirmed by using IR, UV-Visible, 1H NMR, and 13C NMR spectroscopy. The Cu (II), Ni (II) and Co (II) complexes were confirmed by using IR and VU-Visible spectra. The IR spectra of ligands and its metal complexes imply that the benzimidazol derivative ligands behave as basic bidentate ligands coordination through the azomethine nitrogen and oxygen atom. In-vitro antibacterial activity of all the synthesized ligands and their metal complexes were evaluated by using disc diffusion method against K. pneumoniae, E. coli, and S. aureus bacterial species .The tested compounds and metal complexes exhibited from good to excellent activity (zone of inhibition (ZI) ranged 10 mm to 23 mm). Compound BIL1 exhibited better activity than the standard drug against E. coli (ZI of 15 mm) and K. pneumoniae (ZI of 5 mm)compared with gentamycin ((ZI of 15mm). Complex CoC exhibited better activity against S. aureus (ZI of 23 mm) compared with gentamicine (ZI value of 21 mm). This compound is a good starting point to develop new drug for treating pathogenic diseases. Therefore, synthesis of more analogue were recommended for further discovery of a new drug candidate.

Hierarchical packing of racemic metallosupramolecular cages with Ni(II)-based triple-stranded helicate building blocks.

Three novel hierarchical Ni-based metallosupramolecular cages were constructed from nickel ions, pyridine dicarboxylates and isophthalate derivative ligands (the substituents on C5 of isophthalate are methyl, tert-butyl and bromo groups). In every cage, two multinuclear nickel clusters, assembled from four nickel atoms and three pyridine dicarboxylate ligands, are interlinked by three isophthalate-derivative ligands to form a nickel-based triple-stranded helicate (TSH), which then becomes the supramolecular building block for the fabrication of a metallocage. Six homochiral TSH supramolecular building blocks, either left (M)-handed or right (P)-handed, are connected by four linking nickel atoms to generate M6 and P6 discrete racemic cage molecules (M6 - cage with six M-TSHs; P6 - cage with six P-TSHs). The crystal packing of the racemic cages was characterized by single-crystal X-ray diffraction. An additional cobalt-based molecular cage with 5-methylisophthalate bridging ligands was synthesized for host-guest interaction studies. The methyl groups in Co- and Ni-TSH can act as guest units to be accommodated in the cone-shaped metal clusters (host) of an adjacent cage.

Synthesis, cytotoxicity and antibacterial activities of ruthenium, rhodium and iridium metal complexes containing diazafluorene functionalized ligands

New structurally related Ru(II), Rh(III) and Ir(III) N∩N chelating complexes of general formula [(arene)M(κ2(N∩N)L)Cl]PF6 (where arene = p-cymene, benzene and Cp*, M = Ru, Rh and Ir and L = 4,5 diazafluorene derivative ligands) have been designed and synthesized. All the complexes have been characterized by physicochemical and spectroscopic methods (FT-IR, NMR, UV, HRMS). The presence of a distorted octahedral geometry around the metal ion was confirmed by single crystal X-ray diffraction studies. The synthesized ligands, along with their metal complexes, were screened for their in-vitro antibacterial activity against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive (Bacillus thuringiensis and Staphylococcus aureus) bacterial strains and also for in-vitro antioxidant and cytotoxicity activities. Results of antibacterial activity revealed that the metal complexes possess good antibacterial activity. Cytotoxicity results displayed that the compounds act as potent anticancer agents.

Dirhodium(II)/Phosphine Catalyst with Chiral Environment at Bridging Site and Its Application in Enantioselective Atropisomer Synthesis.

A dirhodium(II)/phosphine catalyst with a chiral environment at the bridging site was developed for the asymmetric arylation of phenanthrene-9,10-diones with arylboronic acids. In contrast to the classic chiral bridging carboxylic acid (or derivatives) ligand strategy of bimetallic dirhodium(II) catalysis, in this reaction, tuning both axial and bridging ligands realized the first Rh2(OAc)4/phosphine-catalyzed highly enantioselective carbonyl addition reaction. The kinetic analysis reveals that dirhodium(II) and arylboronic acid follow the first-order kinetics, while phenanthrene-9,10-dione is zeroth-order. These data supported the proposed catalytic cycle, where the key intermediate in the rate-determining step involved the dirhodium(II) complex and arylboronic acid. Finally, axially chiral biaryls were prepared based on a newly developed oxidative ring-opening reaction of α-hydroxyl ketones with a base and molecular oxygen, which featured a central-to-axial chirality transfer radical β-scission step.

Spectroscopic, Anti-Cancer Activity, and DFT Computational Studies of Pt(II) Complexes with 1-Benzyl-3-phenylthiourea and Phosphine/Diamine Ligands

The reaction between [PtCl2(L-L)] (L-L = dppe, dppp, dppb, dppf, Phen and Bipy) or [PtCl2(PPh3)2] with 1-benzyl-3-phenylthiourea (H2BPT) in a basic medium (CHCl3/EtOH) created new coordinated square planner Pt(II) complexes with [Pt(BPT)(L-L)] (1–4,6,7) and [Pt(BPT)(PPh3)2] (5) types. These complexes were fully characterized by analytical and spectroscopic techniques (i.e., IR, UV. Vis., 1H, and 31P NMR). The results indicated that the thiourea derivative ligand act as a dianion ligand bonded through both S and N atoms in a chelating mode or as a mono-anion ligand coordinated through a sulfur atom with Pt(II) ion. Cytotoxicity activity was performed by the MTT assay to determine anti-cancer activities against MCF-7 breast cancer cells. The study indicated that IC50 values for MCF-7 cells were 10.96–78.90 µM. Additionally, the complexes [Pt(BPT)(dppe)] (1), [Pt(BPT)(PPh3)2] (5), and [Pt(BPT)2(Bipy)] (7) were investigated theoretically, where their quantum parameters were evaluated using the Gaussian 09 program using the theory of B3LYP/Def2TZVP//B3LYP/Lanl2dz. The calculation results confirmed the optimized structures of the complexes square planar geometry. However, the calculated bond lengths and angles showed a slightly distorted square planar geometry due to the trans influence of the sulfur atom. Additionally, complexes of [Pt(BPT)(dppe)] (1) and [Pt(BPT)(PPh3)2] (5) showed higher stability compared to [Pt(BPT)2(Bipy)] (7), which can be attributed to the higher back-donation of (1) and (5) complexes. Furthermore, among the three complexes, the [Pt(BPT)2(Bipy)] (7) complex possessed the lowest HOMO–LUMO gap, which may be a good candidate as the photo-catalyst material.

Surface-enhanced Raman spectroscopy for studying the interaction of N-propyl substituted imidazole compound with salmon sperm DNA.

Surface Enhanced Raman Spectroscopy (SERS) is a very promising and fast technique for studying drugs and for detecting chemical nature of a molecule and DNA interaction. In the current study, SERS is employed to check the interaction of different concentrations of n-propyl imidazole derivative ligand with salmon sperm DNA using silver nanoparticles as SERS substrates. Multivariate data analysis technique like principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) are employed for the detailed analysis of the SERS spectral features associated with the mode of action of the imidazole derivative ligand with DNA. Silver nanoparticles were used as a SERS substrate in DNA-drug interaction. Five different concentrations of ligands were interacted with DNA and mix with Ag-NPs as substrate. The SERS spectra of were acquired for all seven samples and processed using MATLAB. Additionally, PCA and PLS-DA were used to assessed the ability SERS to differentiate interaction of DNA-drug. Differentiating SERS features having changes in their peak position and intensities are observed including 629, 655, 791, 807, 859, 1337, 1377 and 1456cm-1. These SERS features reveal that binding of ligand with DNA is electrostatic in nature, and have specificity to major groove where it forms GC-CG interstrand cross-linking with the DNA double helix. SERS give significant information regarding to Drug-DNA interaction mechanism, SERS spectra inferred the mode of action of anticancer compound that are imidazole in nature.

Enhancing electrochemiluminescence by assembling ACQ ligands into Hf-based metal-organic framework nanosheet: A novel ECL emitter for fabricating ultrasensitive biosensor

Polycyclic aromatic hydrocarbons (PAHs) are classic electrochemiluminescence (ECL) materials. However, the ECL performance of PAHs aggregates in water phase is limited owing to the aggregation-induced quenching (ACQ) effect of PAHs. To surmount this shortcoming, we proposed an innovative strategy for enhancing the ECL performance by assembling PAH derivative ligands into metal-organic framework nanosheets (MONs), which can separate ACQphores to eliminate the ACQ effect. Gratifyingly, the ECL intensity of Hf-DEADB MON (DEADB = 4,4′-(diethylanthracene-9,10-diyl)dibenzoate) prepared according to the strategy was 5.71-fold higher than that of H2DEADB aggregates. This improvement occurred not only because the distance between the ACQphores in the Hf-DEADB MON was enlarged to surmount the ACQ effect but also because the ultrathin porous Hf-DEADB MON could shorten the diffusion pathways of ion/electron and co-reactant, which boosted electrochemical activation of DEADB luminophores. Given the prominent ECL performance of Hf-DEADB MON, it was used to fabricate a hypersensitive biosensor for detecting microRNA-21, displaying a broad response range (100 aM–10 nM) with an ultralow detection limit (24 aM). Overall, our work developed a promising strategy to eradicate the ACQ effect of PAHs for ECL enhancement, thus pointing out a new direction to design high-efficient ECL materials for constructing ultrasensitive ECL sensors.

New schiff base ligand type [LH2] donor derevative from 4-Aminophenol with Manganese (II), Cobalt(II), Nickal(II), and Copper(II)

The condensation reaction between dimethylglyoxime, acetic acid, and 4-aminophenol was significantly influenced by the [LH2] type donor derivative ligand. The reaction was conducted in methanol for 24 hours while being stirred and refluxed. The syntheses forming a new (2E,3E)-butane-2,3-dione O2-((E)-1-((4-hydroxyphenyl)imino)ethyl) O3-((Z)-1-((4-hydroxyphenyl)imino)ethyl) dioxime) dioxime ligand type [LH2]. Spectroscopic techniques (FT-IR and UV-Vis), elemental analysis (CHN), magnetic susceptibility testing, thin-layer chromatography (TLC), X-RD powder diffraction, 1H-NMR molar conductance, and other methods have been used to characterize the ligand and its complexes with the general formula [M(LH2)] where [M= Mn(II), Co(II), Ni(II), and Cu(II), and [LH2] = donor atoms ligand with N4 and O]. Our study reveals the formation of a new ligand and new complexes with trigonal bipyramid geometrical shape around the Manganese(II), Cobalt(II), Nickel(II), and Copper(II) metal ions. Biological function using the agar disc diffusion method for the ligand and its complexes showed considerable activity against one kind of bacteria (Staphylococcus aureus) after being exposed to two types of bacteria (Staphylococcus aureus and Escherichia coli).

Cytotoxic Effects of New Palladium(II) Complexes with Thiazine or Thiazoline Derivative Ligands in Tumor Cell Lines.

The synthesis of analogs of cisplatin, which is a widely used chemotherapeutic agent, using other metal centers could be an alternative for cancer treatment. Pd(II) could be a substitute for Pt(II) due to its coordination chemistry similarity. For that reason, six squared-planar Pd(II) complexes with thiazine and thiazoline ligands and formula [PdCl2(L)] were synthesized and characterized in this work. The potential anticarcinogenic ability of the compounds was studied via cytotoxicity assay in three different human tumor cell lines, i.e., epithelial cervix carcinoma (HeLa), promyelocytic leukemia (HL-60), and histiocytic lymphoma (U-937). Data obtained showed that complexes with methyl substitutions did not modify cell viability, while no-methyl substituted compounds had a moderate cytotoxic effect on all three cell lines. The complexes with phenyl substitutions displayed the lowest IC50 values, which ranged between 46.39 ± 3.99 μM and 62.74 ± 6.45 μM. Moreover, Pd accumulation inside the cell was observed after incubation with any of the four complexes mentioned, and the two complexes with phenyl rings were found to induce an increase in the percentage of apoptotic cells. These results suggested that the presence of bulky substitutions on the ligands such as phenyl groups may influence the cytotoxicity of the chemotherapeutic agents synthesized.

Micelle Sensitized Physicochemical Studies on Erbium(III) Complexes with Hypoglycemic Sulfonylurea Drugs

Hypoglycemic sulfonylurea derivatives ligands viz. glimepiride, glibenclamide, gliclazide and glipizide show interaction with lanthanide metal Er (III) in non-micellar and micellar medium. Anionic, cationic and non-ionic surfactant micellar media show great variation in oscillator strength of Er (III) with hypoglycemic sulfonylurea drugs as reflected in UVVisible absorption spectra. Interpretation of UVVisible absorption spectra produced that 4G11/2 ← 4I15/2 and 2H11/2 ← 4I15/2 electronic transition bands show different behavior on account of oscillator strength (P) compared to other electronic f-f transitions, depicted as hypersensitive peaks which are characterized as ratio of Pmicellar / PDMF. Exploitation of different parameters viz: oscillator strength (P), Judd-Ofelt parameter Tλ, nephelauxetic effect 𝛽 and bonding parameter b1/2 from absorption spectra supports the covalency characters in metal ligand Er (III)-drugs doped systems to a greater extent. Thermodynamic exploits of hypersensitive transition correlate the spectroscopic data via Work function A, Thermodynamic efficiency of transition TET and Partition function Q. Thermodynamic parameters notify the microscopic behaviour of Er (III)- sulfonylurea drugs.

Visible-Light-Induced Phenoxyl Radical-based Metal–Organic Framework for Selective Photooxidation of Sulfides

Phenoxyl radicals originating from phenols through oxidation or photoinduction are relatively stable and exhibit mild oxidative activity, which endows them with the potential for photocatalysis. Herein, a stable and recyclable metal-organic framework Zr-MOF-OH constructed of a binaphthol derivative ligand has been synthesized and functions as an efficient heterogeneous photocatalyst. Zr-MOF-OH shows fairly good catalytic activity and substrate compatibility toward the selective oxidation of sulfides to sulfoxides under visible light irradiation. Such irradiation of Zr-MOF-OH converts the phenolic hydroxyl groups of the binaphthol derivative ligand to phenoxyl radicals through excited state intramolecular proton transfer, and the excited state photocatalyst triggers the single-electron oxidation of the sulfide. No reactive oxygen species are produced in the photocatalytic process, and triplet O2 directly participates in the reaction, endowing Zr-MOF-OH with wide substrate compatibility and high selectivity, which also proposes a promising pathway for the direct activation of substrates via phenoxyl radicals.

Crystal structures, antioxidant, electrochemical and in-situ spectroelectrochemical properties of new bisthiocarbohydrazones and their Ni(II) complexes

Four new isatin bisthiocarbohydrazone ligands (H2L1, H2L2, H2L3, H2L4) were synthesized by the condensation of salicylaldehyde, 5-bromosalicylaldehyde, 5-chlorosalicylaldehyde and 5-nitrosalicylaldehyde with isatin monothiocarbohydrazone, respectively. The mixed ligand Ni(II) complexes {[NiL1(P)], [NiL2(P)], [NiL3(P)] and [NiL4(P)]} containing triphenylphosphine (P: triphenylphosphine, PPh3) of these bisthiocarbohydrazone ligands were synthesized. The synthesized compounds were characterized by elemental analysis, FT-IR, 1H NMR, UV–Vis spectroscopy techniques and conductivity measurements. In the complexes, the bisthiocarbohydrazone ligands coordinate to nickel through ONS mode. The complexes are diamagnetic and exhibit square planar geometry. The crystal structures of two ligands, H2L1 and H2L3, and two complexes, [NiL1(P)] and [Ni3(L3)2(P)2], whose single crystals were obtained, were determined by single crystal X-ray diffraction technique. The crystal structure of [NiL1(P)] complex is monomeric and compatible with the structure of the solid complex. A new trinuclear Ni(II) complex, [Ni3(L3)2(P)2], was obtained by the crystallization of monomeric solid [NiL3(P)] complex in a different solvent mixture. Redox properties of bisthiocarbohydrazone ligands (H2L1-H2L4) bearing S1 or S2 substituents and their nickel(II) complexes {[NiL1(P)]-[NiL4(P)]} were investigated with cyclic voltammetry and in situ spectroelectrochemistry. Voltammetric analyses indicated that all ligands exhibited four quasi-reversible reduction and one irreversible oxidation process. Complexation of the ligands with Ni(II) cation decreased the number of the reduction processes and caused these processes to have more negative potentials. Significant spectral changes were also observed in the in situ spectroelectrochemical analysis due to electron transfer reactions. In addition, electrochemical responses of monosubstituted salicylaldehyde derivative isatin bisthiocarbohydrazone ligands and their nickel(II) complexes were compared with their disubstituted derivatives.

Synthesis and computational studies of novel cobalt(II) and oxovanadium(IV) complexes of quinoline carbaldehyde derivative ligand for antibacterial and antioxidant applications

Novel metal complexes [Co(HL)2(H2O)2)] (1) and [VO(HL)2] (2) were synthesized using 2-((2-hydroxyethyl)amino)quinoline-3-carbaldehyde, ligand in 1:2 metal–ligand ratio in methanolic solution. The compounds were characterized with 1HNMR, 13CNMR, UV–Visible spectroscopy, fluorescence spectroscopy, FTIR Spectroscopy; powder X-Ray Diffraction, Scanning Electron Microscopy – Energy Dispersive X-Ray Spectroscopy, Mass Spectroscopy and thermogravimetric analysis. The FTIR spectral data showed that the ligand is bidentate that bound to metal ions through the nitrogen of amine (NH) and the deprotonated hydroxyl group (OH). The powder XRD and SEM results indicate that both the complexes showed polycrystalline nature. The formation constants of the complexes were determined spectroscopically and the values are 2.05 × 106 and 6.29 × 105 for Co(II) and V(IV) complexes respectively). Both metal complexes are stable at the specified temperatures, and the thermodynamic parameters indicated that the reactions are spontaneous with exothermic nature of metal-ligand interactions. Antibacterial activities of the complexes were evaluated with disk diffusion and agar dilution method. The Co(II) complex showed recognizable bacterial activity, against Pseudomonas aeruginosa with mean inhibition zone of 20.65 ± 0.18, with minimum inhibitory concentration (MIC) values of 3.25 µg/mL. Additionally, the antioxidant activity of the complexes were also determined in vitro using 1,1-diphenyl-2-picryl hydrazyl, in which Co(II) complex showed higher antioxidant activities with half maximal inhibitory concentrations IC50 of 9.15 µg/ml. The results of binding mode of these compounds against receptors Escherichia coli, Pseudomonas aeruginosa and Streptococcus pyogenes were in good agreement with the in vitro biological activity results.

Macrophages Mediate Healing Properties of Fenofibrate in Experimental Chagasic Cardiomyopathy

Chronic cardiomyopathy is one of the most relevant outcomes of Chagas disease associated with parasite persistence and exacerbated inflammatory response. Fenofibrate, a third generation fibric acid derivative and peroxisome proliferator-activated receptor-α ligand, is involved in the regulation of inflammatory response. However, the participation of macrophages in this scenario has not been elucidated. Here we show, for the first time, that macrophages play a fundamental role in the fenofibrate-mediated modulation of heart pro-inflammatory response and fibrosis caused by the infection with Trypanosoma cruzi. Furthermore, macrophages are required for fenofibrate to improve the loss of ventricular function and this restoration correlates with an anti-inflammatory microenvironment. Understanding the contributions of macrophages to the healing properties of fenofibrate reinforces its potential use as a therapeutic drug, with the aim of helping to solve a public health problem, such as chronic Chagas disease.

Ligand Control of Oxidation and Crystallographic Disorder in the Isolation of Hexavalent Uranium Mono-Oxo Complexes

The development of high-valent transuranic chemistry requires robust methodologies to access and fully characterize reactive species. We have recently demonstrated that the reducing nature of imidophosphorane ligands supports the two-electron oxidation of U4+ to U6+ and established the use of this ligand to evaluate the inverse-trans-influence (ITI) in actinide metal-ligand multiple bond (MLMB) complexes. To extend this methodology and analysis to transuranic complexes, new small-scale synthetic strategies and lower-symmetry ligand derivatives are necessary to improve crystallinity and reduce crystallographic disorder. To this end, the synthesis of two new imidophosphorane ligands, [N═PtBu(pip)2]- (NPC1) and [N═PtBu(pyrr)2]- (NPC2) (pip = piperidinyl; pyrr = pyrrolidinyl), is presented, which break pseudo-C3 axes in the tetravalent complexes, U[NPC1]4 and U[NPC2]4. The reaction of these complexes with two-electron oxygen-atom-transfer reagents (N2O, trimethylamine N-oxide (TMAO) and 2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene (dbabhNO)) yields the U6+ mono-oxo complexes U(O)[NPC1]4 and U(O)[NPC2]4. This methodology is optimized for direct translation to transuranic elements. Of the two ligands, the NPC2 framework is most suitable for facilitating detailed bonding analysis and assessment of the ITI. Theoretical evaluation of the U-(NPC) bonding confirms a substantial difference between axially and equatorially bonded N atoms, revealing markedly more covalent U-Nax interactions. The U 6d + 5f combined contribution for U-Nax is nearly double that of U-Neq, accounting for ITI shortening and increased bond order of the axial bond. Two distinct N-atom hybridizations in the pyrrolidine/piperidine rings are noted across the complexes, with approximate sp2 and sp3 configurations describing the slightly shorter P-N"planar" and slightly longer P-N"pyramidal" bonds, respectively. In all complexes, the NPC2 ligands feature more planar N atoms than NPC1, in accordance with a higher electron-donating capacity of the former.

Simultaneous reduction of 4-nitrophenol, 4-nitroaniline and methylene blue organic pollutants via TiO2 supported Pd(II) complex catalyst bearing 2-(6-methylpyridin-2-yl)-1H-benzimidazole type ligand

In this study, 2-(6-methylpyridin-2-yl)-1H-benzimidazole derivative ligand (L) and its Pd(II) complex (Pd(L)Cl2) were synthesized and characterized by spectroscopic techniques. The crystal structure of L was characterized by X-ray diffraction method, and the structural, spectroscopic and electronic properties were obtained using density functional method (DFT). The catalyst material of the Pd(II) complex was prepared by attaching the complex to the titanium dioxide (TiO2) inorganic support material at a ratio 15 % (15 % Pd(L)Cl2-TiO2). 15 % Pd(L)Cl2-TiO2 catalyst material was characterized by FT-IR, TG, SEM-EDX and XRD analysis methods and used as catalyst in the catalytic reduction of 4-nitrophenol (4-NP), 4-nitroaniline (4-NA) and methylene blue (MB) organic pollutants. High conversion values were obtained for the reduction of 4-NP, 4-NA and MB substrates by 15 % Pd(L)Cl2-TiO2 catalyst material as a synergistic result of the unique catalytic properties of the Pd metal and the photocatalyst property of the TiO2 semiconductor that used as the inorganic support material.

Design and synthesis of a solution-processed redox-active bis(formazanate) zinc complex for resistive switching applications.

In this paper, we report the synthesis and characterization of a mononuclear zinc complex (1) containing a redox-active bis(4-antipyrinyl) derivative of the 3-cyanoformazanate ligand. Complex 1 was readily obtained by refluxing zinc acetate with 3-cyano-1,5-(4-antipyrinyl)formazan (LH) in a methanolic solution. Single-crystal X-ray diffraction analysis of complex 1 shows that the formazanate ligands bind to the zinc center in a five-member chelate "open" form via the 1- and 4-positions of the 1,2,4,5-tetraazapentadienyl formazanate backbone leading to the formation of the mononuclear bis(formazanate) zinc complex exhibiting a distorted octahedral geometry. We also report the study of resistive-switching random access memory application of this solution-processable bis(formazanate) Zn(II) complex to facilitate the practical implementation of transition metal complex-based molecular memory devices. The complex demonstrated high conductance switching with a large ON-OFF ratio, good stability, and a long retention time. A trap-controlled space charge limited current mechanism is proposed for the observed resistive switching behavior of the device, wherein the role played by the [ZnIIL2] complex that comprises the extended redox-active conjugated ligand backbone is revealed by corroborating electrochemical studies, spectrochemical experiments, and DFT calculations. In addition to providing significant insights into the molecular design of transition metal complexes for memory applications, this study also presents the utilization of ZnIIL2 towards the realization of non-volatile resistive random access memory (RRAM) devices with inorganic/organic hybrid active layers that are highly cost-effective and sustainable. These devices exhibited multilevel switching and low current operation, both of which are desirable for advanced memory applications.

In vitro and in vivo antitumor activity of novel half-sandwich ruthenium complexes containing quinoline derivative ligands.

A series of half-sandwich ruthenium complexes containing quinoline derivative ligands was synthesized, which had excellent antitumor toxicity toward a variety of cell lines and could localize lysosomes. The damage of lysosomes promotes the release of cathepsin B and initiates downstream apoptotic cascade signals. The increase in reactive oxygen species (ROS) caused by the decrease in mitochondrial membrane potential (ΔΨm) synergistically amplified the damage degree of lysosomes. In addition, the complex could inhibit cell transfer and clone formation. In vivo results showed that the complex had excellent biological effects in tested mouse samples as the body weight of mice did not change much during the treatment, and the mean tumor volume was significantly lower than the control group.

Synthesis and Characterization of Ru(III) Complexes Containing Quinazoline Derivatives and their Biological and Catalytic Activities

Ruthenium trichloride trihydrate (RuCl3·3H2O) reacted with quinazoline derivative ligands (L) in 1:1 mole ratio in acetone to yield a series of brown/green/greenish black ruthenium(III) complexes of the type RuX3L·nH2O where X = Cl, n = 0, 1, 2 and 3 and L is 6-R-5,6-dihydrobenzoimidazo[1,2- c]quinazoline (R = ethyl: L1/n or i-propyl: L2, L3/n or i-butyl: L4, L5/phenyl: L6/furyl: L7/thiophenyl: L8/o or p-hydroxyphenyl: L9, L10/o or p-chlorophenyl: L11, L12/dimethylaminophenyl: L13). All the synthesized Ru(III) complexes were characterized by elemental analyses, conductivity measurements, infrared, electronic, ESR and mass spectral techniques, TGA, magnetic susceptibility and electrochemical studies. A square pyramidal geometry around the metal ion was proposed for all the complexes. The biological activities of the ligand and its ruthenium(III) complexes have been studied on microorganisms such as B. subtilis, E. coli and yeast by cup-plate method. The catalytic activity of the synthesized ruthenium(III) complexes towards oxidation of benzyl alcohol, cyclohexanol and hydroquinone was also carried out in acetonitrile with tert.-butyl hydroperoxide (t-BuOOH) as co-oxidant.

Aggregated coordination polymers of Ag+ with a cysteine derivative ligand containing an AIEgen.

We investigated coordination polymers of Ag+ with a cysteine-based thiol ligand designed to contain a tetraphenylethylene AIEgen (L- and D-1). The coordination polymers, forming in a variety of protic and aprotic organic solvents, such as THF, CH3CN and CH3OH, were shown to undergo aggregation in H2O/THF binary solvents at water volume fractions above 50%, where emission was substantially enhanced while the CD profile was reversed, yet the dependence of the CD signal on ee remained S-shaped for the polymers in the aprotic organic solvents THF and CH3CN, in contrast to that in protic solvents CH3OH and C2H5OH.