Ligands L1 Research Articles

Molecular docking, dynamics, and quantum chemical study of vanillylacetone and beta-hydroxy ketone derivatives against Mpro of SARS-CoV-2

This study is carried out to find novel active drug candidates which can effectively bind to key residues of main protease (Mpro) of SARS-CoV-2. We performed molecular docking of fifty-seven (57) ligands from two classes: vanillylacetone and its derivatives and beta-hydroxy ketone derivatives against Mpro of SARS-CoV-2. We also docked three antiviral drugs as reference/benchmark drugs including remdesivir (RDV), chloroquine (CQ), and hydroxychloroquine (HCQ) against Mpro for comparison of inhibition tendencies of selected ligands. Binding energies of our reference drugs are as: CQ = -5.1 kcal mol-1 (with predicted inhibition constant (Ki pred) = 177 μmol), HCQ = -5.7 kcal mol-1 (Ki pred = 64.07 μmol) and RDV -6.3 kcal mol-1 (Ki pred = 13.95 μmol). We got remarkable results for our docked ligands as 79% of total ligands indicated binding energies better than CQ, 39 % better than both HCQ and CQ, and 19 % better than all reference drugs. More interestingly interaction analysis of eight best-docked ligands showed that they interacted with desired key residues of Mpro. We further selected the four best-docked ligands L1 = -6.6 kcal mol-1 (Ki pred =13.95 μmol), L6 = -7.0 kcal mol-1 (Ki pred = 7.08 μmol), L34 = -6.0 kcal mol-1 (Ki pred = 38.54 μmol), and L50 = -6.6 kcal mol-1 (Ki pred =13.95 umol) for further analysis by quantum chemical study, molecular dynamic (MD) simulations and ADMET analysis. We have also carried out MD-simulations of six more docked ligand L2, L14, L20, L36, L46 and L48 some of which were showing weak binding affinities and some average binding affinities to check their simulation behavior. Their RMSD, RMSF and binding free energy results were also quite satisfying. We believe the current investigation will evoke the scientific community and highlights the potential of selected compounds for potential use as antiviral compounds against Mpro of SARS-CoV-2.

In vitro cytotoxicity activity of copper complexes of imine and amine ligands: A combined experimental and computational study

Two new Cu(II) complexes [CuL1 (µ1,3-NCS)]2, 2ClO4 (A) and [CuL2 (NCS)2] (B) with Schiff base ligand L1 and reduced Schiff base ligand L2 have been synthesized and characterized by various spectroscopic and electrochemical methods along with single crystal XRD techniques. X-ray diffraction analysis confirms the formation of binuclear (A) and mononuclear (B) complexes. Hirshfeld surfaces analysis of the two complexes and their associated two-dimensional fingerprint plots are plotted. The metal complexes were optimized by using the density functional theory (DFT) comprising Becke’s three parameters exchange potential and Lee-Yang-Parr correlation functional (B3LYP) method, with 6-31G(d,p) basis set for the ligand atoms and LANL2DZ for the central metal ions. The synthesized binuclear Complex A and mononuclear Complex B were screened for their in vitro anticancer activity against human colon adenocarcinoma cells (HT-29) and human hepatoma cell line (Hep-G2) and HeLa cell line. Activity results proved that Complex A has excellent antiproliferative activity against colon carcinoma whereas Complex B is active against hepatocellular carcinoma and cervical cancer.

Mn2+ Bispidine Complex Combining Exceptional Stability, Inertness, and MRI Efficiency.

As an essential metal ion and an efficient relaxation agent, Mn2+ holds a great promise to replace Gd3+ in magnetic resonance imaging (MRI) contrast agent applications, if its stable and inert complexation can be achieved. Toward this goal, four pyridine and one carboxylate pendants have been introduced in coordinating positions on the bispidine platform to yield ligand L3. Thanks to its rigid and preorganized structure and perfect size match for Mn2+, L3 provides remarkably high thermodynamic stability (log KMnL = 19.47), selectivity over the major biological competitor Zn2+ (log(KMnL/KZnL) = 4.4), and kinetic inertness. Solid-state X-ray data show that [MnL3(MeOH)](OTf)2 has an unusual eight-coordinate structure with a coordinated solvent molecule, in contrast to the six-coordinate structure of [ZnL3](OTf), underlining that the coordination cavity is perfectly adapted for Mn2+, while it is too large for Zn2+. In aqueous solution, 17O NMR data evidence one inner sphere water and dissociatively activated water exchange (kex298 = 13.5 × 107 s-1) for MnL3. Its water proton relaxivity (r1 = 4.44 mM-1 s-1 at 25 °C, 20 MHz) is about 30% higher than values for typical monohydrated Mn2+ complexes, which is related to its larger molecular size; its relaxation efficiency is similar to that of clinically used Gd3+-based agents. In vivo MRI experiments realized in control mice at 0.02 mmol/kg injected dose indicate good signal enhancement in the kidneys and fast renal clearance. Taken together, MnL3 is the first chelate that combines such excellent stability, selectivity, inertness and relaxation properties, all of primary importance for MRI use.

In Silico ADME and Toxicity Prediction of Benzimidazole Derivatives and Its Cobalt Coordination Compounds. Synthesis, Characterization and Crystal Structure.

As a result of the synthesis, three new solids, cobalt (II) coordination compounds with benzimidazole derivatives, and chlorides were obtained. The ligands that were used in the synthesis were specially synthesized and were commercially unavailable. During the synthesis, a single crystal of the complex with the L1 ligand was obtained and the crystal structure was refined. All coordination compounds were characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. All the obtained data allowed one to determine the formulas of the new compounds, as well as to determine the method of metal-ligand coordination. Thermal analysis allowed to know the temperature stability of the compounds, solids intermediate and final products of pyrolysis. Additionally, volatile decomposition and fragmentation products have been identified. The toxicity of the compounds and their bioavailability were determined using in silico methods. By predicting activity on cell lines, the potential use of compounds as chemotherapeutic agents has been specified. The blood-brain barrier crossing and the gastrointestinal absorption were defined. Pharmaceutical biodistribution was also simulated.

Synthesis, structural characterization and in vitro cytotoxicity assessment of new mononuclear Cu(II) and Co(II) complexes against MDA–MB–231, HCC–1806 and HT–29 cancer cell lines

In the present work, we report the synthesis, structural characterization and in vitro biological evaluation of four mononuclear Cu(II) and Co(II) complexes 1–4 derived from the Schiff base ligand scaffolds L1 and L2. The synthesized complexes 1–4 were systematically characterized by various analytical and spectroscopic techniques (FTIR, EPR, UV–vis and sXRD). DFT calculations were performed to determine the structural, electronic and chemical properties of complexes 1–4 based on their respective HOMO and LUMO energy values. Hirshfeld surface analysis was carried out to examine the intermolecular interactions (CH···O, NH···H, Cl–H···H and OH···O) which define the stability of the crystal lattice. Furthermore, comparative in vitro DNA/BSA binding studies were carried out by employing various biophysical methods which revealed a higher binding propensity for the copper analogues. The antioxidant activity of complexes 1–4 was also evaluated against the free radical DPPH and the results demonstrated a better radical scavenging activity by the copper analogues. In addition, the cytotoxicity of the complexes was evaluated using an SRB assay against MDA–MB–231/HCC1806 (triple negative breast cancer cell lines) and HT–29 (colorectal cancer cell lines), which revealed remarkable cytotoxicity of complex 3 against the tested cancer cell lines. The toxicity profile of the complexes was also evaluated against VERO (normal kidney epithelial) cells, which validated their low toxicity behaviour.

Evaluation of Aminoacetophenoneoxime derivatives of oxime Schiff bases as a new antimicrobial agent.

Schiff bases may be a core to synthesize different new chemical ligands. They also have many biological activities by its azomethine group. Antimicrobial activities of new synthetic oxime derivatives against bacteria and fungi were investigated. o-Aminoacetophenoneoxime (o-AAOX) and m- Aminoacetophenoneoxime (m-AAOX) were used as precursors in the synthesis of five oxime derived ligands (L1-5). Two tridentates (L1 and L4) were derived from o-AAOX and three bidentates (L2, L3, and L5) were derived from m-AAOX. The structure of prepared ligands was confirmed using FT-IR, NMR (1H and 13C), and UV-Visible spectral analysis as well as melting point and element analysis. Antimicrobial activities of five ligands were determined by the disk diffusion method. Only the m-AAOX ligands showed an antimicrobial action. The L2 was the most effective ligand on the tested microorganisms, especially against Staphylococcus aureus (MIC, 8mg/ml) and Candida glabrata (MIC, 5.5mg/ml). The L5 ligand showed only antifungal effect. Kocuria rosea was resistant to all ligands, while Candida albicans was susceptible to most of them. In conclusion; the m-AAOX derivatives are an active compound against bacteria and fungi than the o-AAOX derivatives. The ligand L2 has more inhibitory effects on bacteria, while fungi were inhibited by other m-AAOX derivatives. The new Schiff bases of the m-AAOX derivatives may be regarded as promising antimicrobial agents.

ANTI-CORROSIVE POTENTIALS OF NAPHTHO-QUINONE/NAPHTHA-ALDEHYDE SCHIFF BASES FOR MILD STEEL IN HCL MEDIUM: SYNTHESIS, CHARACTERIZATION AND DFT STUDIES

The corrosion inhibition of four ligands; L1, L2, L3 and L4 synthesized through reflux condensation, and characterized via spectroscopic methods were examined using weight loss measurements and Density Functional Theory(DFT). Factors like ligand’s chemical structure, immersion time, concentration, and temperature which affect efficiency of corrosion inhibition were evaluated. The experimental results revealed declined weight losses from 0.02-0.004g, 0.06-0.00625g and 0.11450- 0.06938g at 303K, 333K, and 363K temperature for concentration increase from 100-500ppm. The increase in weight loss arose from temperature (303-363K) increase. Obtained data denotes declined corrosion rate in the presence of the inhibitors in the acid solutions but decreased as the inhibition concentration increased at each temperature. The highest inhibition efficiency (%ᶯwL) for the ligands at 303K, 333K and 363K temperatures and 500 ppm concentration were observed as 89.39% (L3), 88.36% (L2) and 55.00% (L2) respectively. The exceptional inhibition proficiency of the ligands could be due to the availability of heteroatoms and aromatic rings with π-electrons within their structures. The increase in %ᶯwL for 5 hours immersion was in the order L2<L4<L1<L3, L1<L3<L4<L2 and L3<L1<L4<L2 at 303K, 333K, and 363K temperature respectively with L3 having the highest %ᶯwL at 89.39% at 303K. The desorption process of the ligands upon the mild steel surface (mss) followed Langmuir adsorption isotherm. The ∆Gads values acquired were amid -18.1709 to -35.6765KJ mol-1 suggestive of adsorption of the studied inhibitors on mss been physisorption. Chemical calculations and molecular descriptors of dipole moment(μ), energy gap, EHOMO, and ELUMO were acquired via B3LYP level with 6-31G (d, p) basis, while global reactivity descriptors; global softness(S), global hardness(η), electrophilicity index(ω) were derive and analyze using Koopman’s theorem. The ligands were found to be in good agreement with both experimental and theoretical results. The L3 ligand had the highest EHOMO value of - 8.4696567 denoting greater inhibition potency and conforming to the result obtained from corrosion %ᶯwL. The structural assemblages of the ligands were confirmed using spectroscopic and analytical methods.

Thiophene-Appended Benzothiazole Compounds for Ratiometric Detection of Copper and Cadmium Ions with Comparative Density Functional Theory Studies and Their Application in Real-Time Samples.

A thirst for the development of a simple fluorescence probe for enhanced sensing application has been achieved by synthesizing a stupendous thiophene-appended benzothiazole-conjugated compound L2. The synthesized compound L2 was characterized using nuclear magnetic resonance and mass spectrometry techniques. Furthermore, a photophysical property of L1 and L2 reveals the enhanced emission spectrum of L2 because of a restricted spin-orbital coupling as a result of increased conjugation compared to the ligand L1. Therefore, comparative studies were undertaken for L1 and L2. Henceforth, L2 was deployed for the ratiometric detection of Cd2+ ions in THF:water and L1 for the detection of Cu2+ ions in THF medium. The chemosensor L2 shows an outstanding water tolerance up to 60% and is stable between pH 2 and 7. This level of water tolerance and stability make L2 a suitable probe for analyzing real-time and biological samples. While the cadmium ion was added to L2, there was a significant red shift in emission from 496 to 549 nm, which indicates the controlled ICT due to complex formation. The metal-ligand complexation was also confirmed by noticing a decreased band gap of metal complex compared to the ligand as calculated using Tauc's plot with solid-phase UV data. The stoichiometric ratio was obtained by Job's plot that exhibited a 1:1 ratio of L2 and Cd2+ ions, and the limit of detection (LOD) was found to be 2.25 nM by the photoluminescence spectroscopic technique. The fluorescence lifetime of both L2 and L2-Cd2+ was found to be 58.3 ps and 0.147 ns, respectively. Alongside, the colorimetric-assisted ratiometric detection of Cu2+ by L1 with 1:2 stoichiometric ratio having an LOD of 1.06 × 10-7 M was also performed. Furthermore, the practical applicability of the probe L2 in sensing cadmium was tested in sewage water and vegetable extract; the recovery was approximately 98 and 99%, respectively. The experimental data were supported by theoretical investigation of structures of L1, L2, L1-Cu2+ , and L2-Cd2+ , complex formation, charge transfer mechanism, and band gap measurements done by quantum chemical density functional theory calculations.

Unprecedented cleavage of -N-N- bond of ligand and phenyl ring nitration during nitric oxide (NO) reactivity studies: new ruthenium nitrosyl complex and photoinduced liberation of NO

A two-step procedure was used to make the ruthenium nitrosyl complex [Ru(L3)(PPh3)(NO)Cl2] (1a). The product generated when ligand L1 and [Ru(PPh3)3Cl2] reacted to an acidified nitrite solution treatment. Single-crystal X-ray diffraction was used to determine the crystal structure of (1a). Complex (1a) has a {Ru–NO}6 moiety in the Enemark–Feltham notation and was found to be diamagnetic in nature. Photolytic cleavage of metal-bound NO in (1a) was observed under ultraviolet light, and photoreleased free NO was trapped by reduced myoglobin. The amount of photoreleased NO was estimated by the Griess assay. DFT computations were also performed to authenticate the electronic properties of (1a).

Synthesis, molecular docking, and biological studies of novel heteroleptic Cu(II) and Zn(II) complexes of natural product-based semicarbazone derivatives

In this study, we describe the synthesis of novel heteroleptic Cu(II) and Zn(II) complexes using two semicarbazone-based derivative ligands: ortho-phthalaldehyde disemicarbazone (L1) and dehydrozingerone semicarbazone (L2). The metal salts and the two ligands were used in a 1:1:1 ratio. The complexes were characterized by magnetic moment measurements, elemental analysis, SEM-EDX, liquid chromatography-mass spectrophotometer (LC-MS), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), UV-visible spectrophotometer, NMR, and FT-IR spectroscopy methods. Using the disk diffusion and DPPH procedures, the complexes' potential for scavenging free radicals and having antibacterial effects was examined. The results indicate that the ligand L1 has good mean inhibition zones on S. aureus (12.42 ± 0.23 mm) and S. pyogenes (11.64 ± 0.12 mm) bacteria. The [Cu(L1)(L2)] complex displayed higher antibacterial activities (13.67 ± 0.52 mm) against S. pyogenes bacteria, whereas [Zn(L1)(L2)] shows higher activity against P. Aeruginosa (14.22 ± 0.33 mm). Both complexes showed good antioxidant activity (63.7 % and 59.68 %). Furthermore, the docking results of the compounds against S. aureus Gyrase confirm the ligands (L1 and L2) and the complexes exhibit binding potentials of -7.39 to -11.01 kcal/mol. Higher value was obtained for the [Zn(L1)(L2)] complex (-11.01 kcal/mol). In order to enhance the biological activities of metal complexes, this study sheds light on the significance of multi-semicarbazone ligands and their corresponding complexes.

Iron-Catalyzed Cross-Electrophile Coupling of Inert C–O Bonds with Alkyl Bromides

Iron-Catalyzed Cross-Electrophile Coupling of Inert C–O Bonds with Alkyl Bromides

Bi(III) complexes of piroxicam and meloxicam: Synthesis, characterization, antioxidant, anti-inflammatory and DNA cleavage studies

Piroxicam and meloxicam are therapeutically important compounds and their coordination complexes received immense importance in past few years. In present study, new Bi(III) complexes (1 and 2) of piroxicam (L1) and meloxicam (L2) were synthesized and characterized by spectral and physico-analytical techniques such as UV–Vis, FTIR, SEM-EDX, XRD and TGA. The spectral studies revealed that ligand L1 coordinated with the Bi metal in a bi-dentate manner through its amide oxygen (Oamide) and pyridyl ring nitrogen (Npyridyl) in complex 1. The ligand L2 coordinated through its amide oxygen (Oamide) and thiazolyl ring nitrogen (Nthiazolyl) in the complex 2. SEM and XRD results depicted different surface morphologies of both complexes. The different thermodynamic parameters (Ea, ΔS, ΔH and ΔG) were evaluated by using Coats–Redfern equation. Bio-efficacy of Bi(III) complexes (1 and 2) was evaluated by in-vitro and in-vivo methods, while, DNA cleavage was measured by gel electrophoresis technique. Furthermore, the binding interactions of both complexes with DNA was analysed by molecular docking. The results reveal that both the complexes have higher antioxidant potential and higher safety index up to 1000 mg/Kg (LD50) than free ligands. The complexes significantly inhibited carrageenan induced edema; 84 % inhibition by complex 1 and 71 % inhibition by complex 2. Furthermore, both the complexes have stronger tendency to cleave the DNA than the ligands. The Bi(III) complexes can further be explored in other inflammatory pathways to investigate their exact mechanism behind anti-inflammatory effect.

The Anion-Directed Self-Assembly of tubular helical silver (I)-Based coordination polymers and the adsorption properties of hazardous substances

The controlled synthesis of topologically-structured helical coordination polymers (CPs) using versatile organic linkers and a metal centre, has recently attracted considerable attention. In this study, we design and synthesize a flexible tripodal ligand L1 (where L1 = 1, 3, 5-tris(2-pyridylsulfanylmethyl)-2, 4, 6-triethylbenzene) with an N, S cooperative chelation coordination geometry. In combination with silver salts in the presence of anions (nitrate and hexafluorophosphate), silver(I)-based tubular-shaped coordination polymers 1 ([Ag(NO3)(DMF)L12]n) and 2 ({[Ag(CH3CN)L12]•PF6}n) were precisely constructed through cooperative Ag-N/Ag-S and anion coordination interactions, which influenced the helical structures. Both single-stranded helical silver (I)-based CPs were characterised by NMR, PXRD, XPS, and FT-IR spectroscopy. CPs 1–2 have an irregular tube-like channel within their crystal structure which can capture iodine (adsorption capacity 0.27 g/g) and MnO4¯anions (0.25 eq. PF6¯ anions were exchanged) from their aqueous, or hexane, solution.

Syntheses and Preferred Structure Elucidation of N‐heterocyclic Imine Nickel and Cobalt Catalysts for MMA Polymerization

AbstractHere, L1 (2‐(pyridin‐2‐yl)quinoxaline) and L2 ((1‐((1H‐pyrrol‐2‐yl)ethylidene)benzene‐1,2‐diamine) ⋅ (1‐(1H‐pyrrol‐2‐yl)ethanone)) were synthesized and reacted with CoCl2 ⋅ 6H2O and NiCl2 ⋅ 6H2O to produce complexes 1–4. We found several interesting pieces of crystal structure information. Firstly, ligands L1 and L2 with completely different molecular structures were obtained by reacting the precursors containing similar N‐heterocycles with 1,2‐diaminobenzene. Secondly, in methanol and DMF solvents, 1 showed two structures, the binuclear and mononuclear cobalt complexes 1 a and 1 b. Finally, the structure of 4 showed the formation of a new 2 : 1 type ligand at eutectic L2 in the presence of a Ni2+ template. Upon treatment with AIBN, 1–4 showed moderate to high activities for MMA polymerization, producing PMMA with low to high molecular weights (2.02∼73.03×104 g⋅mol‐1) and moderate dispersity indices (PDI: 1.72∼3.32). Moreover, 1 b displayed higher catalytic activities (up to 1.138×105 g mol−1 ⋅ h−1), which was 20 times higher than that of 3 and more than 7 times higher than that of 1 a.

A water-stable Eu-MOF as multi-responsive luminescent sensor for high-efficiency detection of Fe3+, MnO4− ions and nicosulfuron in aqueous solution

Effective detection of contaminants in water, such as pesticides, excess Fe3+ and MnO4−, is critical to human health and environmental protection. They can be quantitatively detected by a new luminescent sensor based on a water stable europium metal-organic framework (Eu-MOF). The dual nucleus Eu-MOF is connected by L6−ligands through μ6: η1, η2, η3, η3, η4, η5 coordination to form a 2D wavy network, and then expands into a three-dimensional structure through ligand L6− connection. Due to its high water stability and multiple emission centers, the Eu-MOF can be used as luminescence sensors for pollutants in water. Eu-MOF exhibits high selectivity for Fe3+, MnO4−, and nicosulfuron (NSF) in water through luminescence quenching with low detection limit, and fast response, indicating that Eu-MOF is a reliable analysis platform for multi-responsive sensing.

Theoretical Insights into Phenanthroline-Based Ligands toward the Separation of Am(III)/Eu(III).

The bistriazinyl-phenanthroline representative ligand, BTPhen, shows excellent extraction and separation ability for trivalent actinides and lanthanides. Herein, we first designed three phenanthroline-based nitrogen-donor ligands (L1, L2, and L3), and then studied the structural and bonding properties as well as thermodynamic properties of the probable complexes, ML(NO3)3 (M = Am or Eu and L = L1, L2, or L3), using scalar relativistic density functional theory. Our charge decomposition analysis revealed an obviously higher charge transfer from the ligand to Am(III) compared with the Eu(III) case for the studied complexes. Spin density analysis further showed a more significant degree of Am-to-ligand spin delocalization and the corresponding spin polarization on the ligands. According to the thermodynamic analysis, ligand L3 has the strongest complexation capacity for both Am(III) and Eu(III) ions, while ligand L1 has the highest Am(III)/Eu(III) selectivity in binary octanol/water solutions. We expected that this work can provide valuable theoretical support for the design of effective ligands for actinide(III)/lanthanide(III) separation in high level liquid waste.

Copper‐Catalyzed Asymmetric Allylic Alkylation of Racemic Cyclic Allyl Bromides with Organolithium Compounds

AbstractOrganolithium reagents are one of the most widely used reagents in chemical synthesis. Herein, we reported the first study of organolithium reagents used in asymmetric allylic alkylation (AAA) reactions with racemic cyclic substrates. A simple and efficient Cu‐catalyzed synthesis of enantiomerically enriched cycloalkene derivatives from various racemic cyclic allylic bromides was developed. The standard method employed 5 % CuBr⋅SMe2 in combination with phosphoramidite ligand L2 in DCM. Meanwhile, transfer of the reactions into flow condition for more convenient application was also studied. This new Cu‐catalyzed protocol was speculated to undergo an enantioconvergent transformation mechanism here.

Relative binding free energy calculations with transformato: A molecular dynamics engine-independent tool.

We present the software package transformato for the setup of large-scale relative binding free energy calculations. Transformato is written in Python as an open source project (https://github.com/wiederm/transformato); in contrast to comparable tools, it is not closely tied to a particular molecular dynamics engine to carry out the underlying simulations. Instead of alchemically transforming a ligand L 1 directly into another L 2, the two ligands are mutated to a common core. Thus, while dummy atoms are required at intermediate states, in particular at the common core state, none are present at the physical endstates. To validate the method, we calculated 76 relative binding free energy differences for five protein–ligand systems. The overall root mean squared error to experimental binding free energies is 1.17 kcal/mol with a Pearson correlation coefficient of 0.73. For selected cases, we checked that the relative binding free energy differences between pairs of ligands do not depend on the choice of the intermediate common core structure. Additionally, we report results with and without hydrogen mass reweighting. The code currently supports OpenMM, CHARMM, and CHARMM/OpenMM directly. Since the program logic to choose and construct alchemical transformation paths is separated from the generation of input and topology/parameter files, extending transformato to support additional molecular dynamics engines is straightforward.

Crystal Structure, Magnetic Study, and Antidiabetic Activity of Ni(II) Complex with N,O‐Donors Ligands

AbstractCoordination chemistry of divalent ions involving multidentate ligands have received limited attention. The present work reports the synthesis of a mixed ligand complex of Ni(II) which is characterized by X‐ray single‐crystal diffraction, thermal, IR spectroscopy, magnetic, and in vitro antidiabetic activity. The atomic arrangement of the complex consists of two Ni(II) bridged by two ligands of organic molecules 5‐(pyridin‐2‐yl)‐1,2,4‐triazol‐1‐ide (Ligand L1) and 2‐(4‐chlorobenzoyl)benzoate (Ligand L2) which throw their nitrogen and oxygen atoms. The Ni2+ adopts a distorted octahedral geometry (NiO2N2(OH2)2). Infrared spectroscopy shows the existence of O─H, C─N, C═O, and absorption bands Ni─(O,N). The thermal study proves that this compound undergoes dehydration then decomposition over a large domain of temperature. The magnetic properties of the complex demonstrate an antiferromagnetic interaction between two adjacent nickel atoms mediated by throw ligand (L1). The antidiabetic effect of this compound is supported by a biological test in vitro and is confirmed by molecular docking suggesting good inhibitory activity of the prepared complex for α‐amylase.

Heterobimetallic Gold/Ruthenium Complexes Synthesized via Post-functionalization and Applied in Dual Photoredox Gold Catalysis.

The synthesis of heterobimetallic AuI /RuII complexes of the general formula syn- and anti-[{AuCl}(L1∩L2){Ru(bpy)2 }][PF6 ]2 is reported. The ditopic bridging ligand L1∩L2 refers to a P,N hybrid ligand composed of phosphine and bipyridine substructures, which was obtained via a post-functionalization strategy based on Diels-Alder reaction between a phosphole and a maleimide moiety. It was found that the stereochemistry at the phosphorus atom of the resulting 7-phosphanorbornene backbone can be controlled by executing the metal coordination and the cycloaddition reaction in a different order. All precursors, as well as the mono- and multimetallic complexes, were isolated and fully characterized by various spectroscopic methods such as NMR, IR, and UV-vis spectroscopy as well as cyclic voltammetry. Photophysical measurements show efficient phosphorescence for the investigated monometallic complex anti-[(L1∩L2){Ru(bpy)2 }][PF6 ]2 and the bimetallic analogue syn-[{AuCl}(L1∩L2){Ru(bpy)2 }][PF6 ]2 , thus indicating a small influence of the {AuCl} fragment on the photoluminescence properties. The heterobimetallic AuI /RuII complexes syn- and anti-[{AuCl}(L1∩L2){Ru(bpy)2 }][PF6 ]2 are both active catalysts in the P-arylation of aryldiazonium salts promoted by visible light with H-phosphonate affording arylphosphonates in yields of up to 91 %. Both dinuclear complexes outperform their monometallic counterparts.