Effect of Coordination Modes of HL Ligand on the Molecular Architecture of Its Transition Metal Complexes (HL = 5-Methyl-2-Phenyl-4-[(2-<Emphasis Type="Italic">o</Emphasis>-Tolylamino)-Phenylmethylene]pyrazol-3(2H)-one)

Abstract  Two Ag⁺ complexes [Ag(HL)₂(PF₆)] (1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2) (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) were synthesized and structurally characterized by EA analysis, IR spectra and X-ray crystallography. The result shows that two expected coordination modes (Modes I and III in Scheme 1) of the HL ligand, can be observed in its Ag⁺ complexes, while not in other transition metal ions (Ni²⁺, Co²⁺ or Cu²⁺) complexes whether deprotonation or not for the HL ligand. Graphical Abstract  Three possible coordination modes (Modes I, II or III in Scheme 1) of the selected HL (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) ligand, can be adopted, in which Modes I and III can be observed in its two Ag⁺ complexes [Ag(HL)₂(PF₆)](1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2), while Mode II just observed in its transition metal ions (Cu²⁺, Ni²⁺, or Co²⁺) complexes, resulting from the deprotonatd form of the HL ligand and the coordination characters of transition metal ions.      

Polymer Complexes. XLIII. EPR, Spectra, and Stereochemical Versatility of Novel Copper(II)Polymer Complexes

Copper(II) polymer complexes of empirical formula [Cu(ligand)₂X₂] (where X = Cl, Br, I, NO₃, and SO₄) and [Cu(ligand)(CH₃COO)₂] have been prepared with poly(3-phenylacrylidine semicarbazone). All the polymer complexes prepared have been characterized by elemental analysis, magnetic moment, conductance, IR, electronic, ¹H-NMR, and electronic paramagnetic resonance spectral studies. The polymer complexes [Cu(ligand)₂X₂] and [Cu(ligand) (CH₃COO)₂] may have tetragonal symmetry while the [Cu(ligand)₂( SO₄)₂] may be five-coordinate trigonal bipyramidal in structure. All complexes exhibit normal magnetic moments corresponding to one unpaired electron except [Cu(ligand)(CH₃COO)₂] which shows a subnormal magnetic moment. EPR spectra of the polymer complexes have been studied with a view to assigning their stereochemistries. Various EPR parameters have been calculated. The g, A, G values for all the polymer complexes are consistent with a tetragonal 1–5 and trigonal bipyramidal 6 stereochemistry in the Cu(II) polymer complexes of homopolymer.     

Adsorption Behaviors of Platinum Group Metals in Simulated High Level Liquid Waste Using Macroporous (MOTDGA-TOA)/SiO2-P Silica-based Absorbent

As fundamental research for separation of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO₂-P adsorbent was prepared by impregnation of N,N′-dimethyl-N,N′-di-n-octyl-thiodiglycolamide (MOTDGA) and Tri-n-octylamine (TOA) into silica/polymer composite support (SiO₂-P). The adsorption behavior of Ru(III), Rh(III), and Pd(II) in simulated HLLW onto the adsorbent were investigated by the batch method to obtain their corresponding equilibrium and kinetic data. The adsorbent showed strong adsorption for Pd(II) and the adsorption reached equilibrium within 2 hr. High distribution coefficient (K _d) values for Pd(II) were obtained in 0.1–1 M HNO₃ concentration. In addition, the use of both MOTDGA and TOA improved adsorption of Ru(III) and Rh(III) better than individual use of them. Especially, the K _d value for Ru(III) towards (MOTDGA-TOA)/SiO₂-P adsorbent was three times larger than that in the adsorption using only with MOTDGA or TOA as extractant. The adsorptions of Ru(III), Rh(III), and Pd(II) followed the Langmuir adsorption model, and were found to be controlled by the chemisorption mechanism.     

The Effect of the Synthetic Conditions on the Deposition and Distribution of Copper Complexes on Polymer Supports

The influence of conditions (e.g., ratios of components, temperature etc.) on the reaction of Cu(OCOCH₃)₂·2H₂O with polyethylene grafted-polyacrylic on the amount of the metal and the composition of the immobilized Cu(II) complexes was studied. The concentration dependence obeys the Langmuir law. Analysis of the data leads to an evaluation of the stability constant for the Cu(II) complexes (K=300 l/mole at 333 K). The constant corresponds to a Cu(II) fixation value, k=0.35 mole/l (22.22 mg Cu(II)/g). The multistage fixation mechanism for Cu(II) complex formation was demonstrated by the marked atom technique. Cu(II) is fixed by one carboxylate group (to 16 mol% of the supported Cu(II), K ₁=16×10^–2 mole/g) and by two carboxylate groups (K ₂=2.54×10^–3 mole/g) of the grafted ligands. The PE-gr-PAA–Cu(II) system mimics the situation-insoluble support-soluble functional polymer covering and realizes the advantages of both the soluble and the three-dimensional crosslinked polymer. Steady-state magnetic susceptibility measurements and ESR spectroscopy were used to study the distribution of cupric ion attached to a polyethylene-grafted poly(acrylic acid) support. The existence of three types of cupric ion complexes was demonstrated: (1) isolated complexes, (2) complexes bonded by dipole–dipole interactions, and (3) clusters with strong exchange interactions. The mean distances between the isolated ions (¯r22–15 Å) and between the dipole–bound complexes (¯r _agreg7 Å) were estimated. The results obtained were compared to the data for other immobilized catalysts. Preliminary results on the fixation of bimetallic Cu(II) and Pd(II) complexes to the polymers as well as on their distributions were obtained.     

Synthesis and structural characterisation of new binuclear Pd(II) complexes with both bridging and terminal pyrazolate ligands

Dinuclear pyrazolato-bridged Pd(II) complexes Pd₂L₄⁰ and Pd₂L₄¹ have been prepared by reacting Pd(Ac)₂ and one equivalent of HL⁰ (3-phenyl-5-(2-pyridyl)pyrazole) or HL¹ (3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole. The new complexes have been characterised by elemental analyses, IR, ¹H NMR and in the case of PdL¹₄ by single crystal X-ray diffraction methods. This structure shows two palladium atoms bridged by two L¹ ligands. The square-planar geometry of each Pd atom is completed by a bidentate chelating L¹ ligand. The six-membered dipalladacycle formed by the two Pd atoms and the two bridging pyrazolato ligands adopts a distorted boat-like conformation.     

Synthesis and Characterization of Novel Polymeric-Schiff Bases and Their Complexes

An investigation of the solid state conductivity of polymeric-Schiff bases derived from the condensation reaction of polyacrylamide and an aldehyde (4-methoxybenzaldehyde and 4-chlorbenzaldehyde) has been carried out and Co(II) and Ni(II) complexes have been prepared. Polymeric-Schiff bases and their metal complexes were characterized by molar conductance, magnetic susceptibility, and electronic and IR spectral studies. Conductivity measurements were carried out at 20 °C in dimethylformamide to determine the electrolytic behavior. The ¹H-NMR and ¹³C-NMR spectra, elemental analysis, and viscosity average molecular mass (M _v) of the polymeric-Schiff bases and their complexes were determined. All of the polymer–metal complexes showed high thermally stability. The DC conductivities of the solid samples were measured using a four-probe technique.     

Synthesis,crystal structure of copper(II) complexes comprising 2-(biphenylazo)phenol and 1-(biphenylazo)naphthol ligands and their catalytic activity in nitroaldol reaction

New series of copper(II) complexes of the type [Cu(L)₂] (L = L₁–L₅) comprising bidentate 2-(biphenylazo)phenol (HL₁–HL₄) and 1-(biphenylazo)naphthol (HL₅) ligands have been synthesized. The composition of complexes and ligands (HL₁–HL₄) has been established by elemental analysis and spectral (FT–IR, UV–Vis, ¹H NMR and EPR) methods. Molecular structures of copper complexes [Cu(L₃)₂] (3) and [Cu(L₅)₂] (5) were established by X-ray crystallography. These Copper(II) biphenylazo complexes exhibit a very good catalytic activity towards nitroaldol reaction of various aldehydes with nitromethane.     

Preparation of a Macroporous Silica-Based Multidentate Soft-Ligand Material and its Application in the Adsorption of Palladium and the Others

To separate Pd(II), a macroporous silica-based soft-ligand 2,6-bis(5,6-di(iso-butyl)-1,2,4-triazine-3-yl)pyridine (BDIBTP) material, BDIBTP/SiO₂-P, was synthesized by vacuum treatment. It was a multidentate chelating composite prepared by impregnation and immobilization of BDIBTP and 1-octanol molecules into the pores of the macroporous SiO₂-P particles with a mean diameter of 50 µm. 1-Octanol was used to modify BDIBTP through intermolecular interaction force. The adsorption of some typical fission products Zr(IV), Pd(II), La(III), Y(III), Ru(III), Rh(III), and Mo(VI) contained in highly active liquid waste (HLW) onto the BDIBTP/ SiO₂-P materials was investigated. It was carried out by examining the effects of contact time and the concentration of HNO₃ in the range of 0.3 M?7.0 M. BDIBTP/SiO₂-P showed excellent adsorption ability and high selectivity for Pd(II) over all of the tested metals. It was ascribed to the effective complexation of Pd(II) with BDIBTP/SiO₂-P. Consideration of the complexation of BDIBTP for minor actinides MAs(III), the possibility and feasibility of effective partitioning of Pd(II) and MAs(III) simultaneously from a simulated HLW were discussed. A new concept process entitled MPS for the MA(III) and Pd(II) Separation has been proposed.     

Neutral Pd(II) and Ni(II) Acetylide Catalysts for the Polymerization of Methyl Methacrylate

Homogenous polymerization of methyl methacrylate using Pd(II)- and Ni(II)-based acetylide complexes as initiators has been investigated. M(PR'₃)₂(CCR)₂ (M=Pd, Ni; R'=PPh₃, Pn-Bu₃; R=Ph, CH₂OH, CH₂OOCCH₃, CH₂OOCPh, CH₂OOCPhOH-o) were found to be a novel type of effective initiators for the polymerization of methyl methacrylate. Among them, Pd(C CPh)₂(PPh₃)₂ (PPP) shows the highest activity in the MMA polymerization and the PMMA obtained is a syndiotactic polymer with high number-average molecular weight (M _n) of 14.1 × 10⁴. Some features and kinetic behavior of MMA polymerization initiated by PPP were studied in detail. The polymerization reaction is first-order with respect to both [PPP] and [MMA]. Radical polymerization mechanism is proposed.     

Cu(II) and Zn(II)-Pyridine-2,3-Dicarboxylate Complexes with 2-Methylimidazole: Syntheses, Crystal Structures, Spectroscopic and Thermal Analyses

Two new Cu(II) and Zn(II)-pyridine-2,3-dicarboxylate (pydc) complexes with 2-methylimidazole (2-Meim), [Cu(pydc)(2-Meim)₃]·H₂O (1) and {[Zn(μ-pydc)(H₂O)(2-Meim)]·H₂O}_n (2) have been synthesized and characterized by elemental, spectral (IR and UV–Vis.) and thermal analyses. The molecular structures of mononuclear (1) and polynuclear (2) complexes have been determined by the single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic P ? 1 space group, while compound 2 crystallizes in the monoclinic P2₁/c space group. The pyridine-2,3-dicarboxylate ligand acts in two different coordination modes; namely, bidentate-(N,O) for 1 and μ-tridentate-(N,O,O) for 2, the latter displaying a 1D polynuclear structure. The crystal packing of the complexes exhibit 3D supramolecular frameworks including channels by C–H···π, π···π, and N–H···O interactions. Water molecules occupy the channels by O–H···O hydrogen bonds.     

Study on Synthesis, Characterization, Thermal Stability and Conductivity Properties of a New Conjugated Oligoazomethine and some of its Metal Complexes

A novel azomethine oligomer of 2,3-bis[(2-hydroxyphenyl)methylene]diaminopyridine (HPMDAP) was first synthesized by oxidative polycondensation reaction using air and NaOCl as oxidative agents. Optimum reaction conditions for the oxidative polycondensation and the main parameters of the process were established. At optimum reaction conditions, the yield of the product was found to be 69%. Oligomeric complexes of 2,3-bis[(2-hydroxyphenyl)methylene]diaminopyridine with Cd(II), Co(II), Cu(II), Ni(II), Fe(II), Pb(II), Cr(III) and Zn(II) were successfully prepared. Structures of monomer, oligomer and some oligomer metal complexes obtained were confirmed by FT-IR, UV–vis, ¹H- and ¹³C-NMR and elemental analysis. Characterization was carried out by TG-DTA, size exclusion chromatography (SEC), magnetic moment and solubility tests. The ¹H- and ¹³C-NMR data showed that polymerization proceed by C–C coupling of ortho and para positions according to –OH group of HPMDAP. Elemental analysis of chelates suggests that the metal ligand ratio is about 1:2. Molecular weight distribution values of the products were determined by size exclusion chromatography (SEC). According to TG analyses, the carbonaceous residues of HPMDAP and OHPMDAP were found to be 34.94 and 29.36% at 1000 °C, respectively. Thermal analyses of Cd, Co, Cu, Ni, Fe, Pb, Cr and Zn oligomer–metal complexes were also investigated under N₂ atmosphere between 15 and 1000 °C. Electrical conductivities of OHPMDAP and its metal complexes were also measured with four probe technique.     

Oxadiazoline and Ketoimine Palladium(II) Complexes as Highly Efficient Catalysts for Suzuki–Miyaura Cross‐Coupling Reactions in Supercritical Carbon Dioxide

The [2+3] cycloaddition of nitriles (RCN) with 2,2‐dimethyl‐3,4‐dihydro‐2H‐pyrrole 1‐oxide, in the presence of palladium dichloride (PdCl₂) gives the corresponding 2,3‐dihydro[1.2.4]oxadiazole (Δ⁴‐1,2,4‐oxadiazoline) palladium(II) complexes 1 – 4 in good yields. However, the Pd(II)‐assisted reaction of pentafluorobenzonitrile with the same pyrroline N‐oxide gives a mixture of oxadiazoline 5 , ketoimine 6 and pyrrolylbenzamide‐ketoimine 7 Pd(II) complexes, which affords upon heating in refluxing acetone the unprecedented fused tricyclic ketoimine complex 8 as the exclusive product. Under heating, compounds 5 and 7 transform to 6 , the latter undergoing intramolecular cyclization by nucleophilic attack of the amino moiety to the ortho carbon of the pentafluorophenyl ring leading ultimately to 8 . The compounds were characterized by IR, ¹H and ¹³C NMR, ESI⁺‐MS, elemental analyses and, in the cases of 3 , 6 , 7 and 8 , also by X‐ray diffraction analyses. The catalytic properties of the Pd complexes were evaluated in Suzuki–Miyaura cross‐coupling reactions, using supercritical carbon dioxide (scCO₂) as a green solvent. Cross‐couplings of aryl halides with phenylboronic acid give the desired biaryl products in quantitative yields, in a short reaction time, for substrate‐to‐catalyst molar ratios as high as 4.0⋅10⁴.     

1D Hydrogen-Bonded Polymers Assembled by Tetraaza Macrocyclic Metal(II) Complexes and Inorganic Salts

The self-assembly of [M(L)]Cl₂·2H₂O (M = Ni²⁺ and Cu²⁺, L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) with sodium 1,2,4-benzenetricarboxylate (Na₃btcb) and KNO₃ generates the 1D hydrogen-bonded polymers with formulas [Ni(L)(H₂btcb^?)₂] (1) and [Cu(L)(NO₃)₂] (2). These polymer complexes have been characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The crystal structure of 1 shows a distorted octahedral coordination geometry around the nickel(II) ion, with the four secondary amines of the macrocycle and two carboxylate oxygen atoms of the H₂btcb^? ligand in the trans position. In 2, the coordination environment around the central copper(II) ion reveals an axially elongated octahedron with four Cu–N bonds and two oxygen atoms of the nitrate ligand in the trans position. The cyclic voltammograms of the complexes undergo two one-electron waves corresponding to M^II/M^III and M^II/M^I processes. The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature of the axial ligands.     

Thermal and Fluorescence Properties of New Nanostructured Hg(ll) -2,2′-Bipyridine Derivative Complexes

Two new nano-structured Hg(II) supramolecular complexes, [Hg(5,5′-di-t-but-bpy)(μ-Br)Br]₂[Hg(5,5′-di-t-but-bpy)Br₂](1) and [Hg(5,5′-di-t-but-bpy)I₂] (2) were synthesized by the sonochemical method. The structures of 1 and 2 were characterized by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR spectroscopy and single crystal X-ray diffraction. Their thermal stabilities were studied by thermogravimetric and differential thermal analyses. Solid-state luminescent spectra of 1 and 2 indicate a fluorescent broad emission band between 304 and 404 nm with excitation at 284 nm. These nanostructured coordination polymers were characterized by scanning electron microscopy, elemental analysis, and IR spectroscopy.     

Arene–RuII Complexes of Curcumin Exert Antitumor Activity via Proteasome Inhibition and Apoptosis Induction

Organometallic ruthenium(II) complexes of general formula [(η⁶‐arene)Ru(curcuminato)Cl], with arene being p‐iPrC₆H₄Me ( 1 ), C₆H₆ ( 2 ), and C₆Me₆ ( 3 ), were synthesized, characterized, and evaluated for their antitumor effects. Specifically, we explored their ability to regulate the proteasome, a validated pharmacological target in cancer treatment. Ruthenium complexes inhibited isolated proteasomes to various extents, with the biological activity of these complexes depending on the nature of the bound arene; in particular, [(η⁶‐arene)Ru(curcuminato)Cl] 2 suppressed proteasomal activities more potently than 1 , 3 , or free curcumin. Each complex also inhibited proteasomes in cultured colon cancer cells and consequently triggered apoptosis, with the [(η⁶‐benzene)Ru(curcuminato)Cl] complex 2 being the most active. The influence on the oxidative status of HCT116 cells and the DNA binding ability of the [(η⁶‐arene)Ru(curcuminato)Cl] complexes were studied. Complex 2 showed the highest antioxidant capacity; moreover, complexes 1 and 2 were shown to bind isolated DNA with higher affinity (up to threefold) than free curcumin. Collectively, our results demonstrate that the complexation of curcumin with ruthenium(II) is a promising starting point for the development of curcumin‐based anticancer drugs.     

Synthesis, Characterization and Anti-microbial Activity of Oligo-N-2-aminopyridinylsalicylaldimine and Some Oligomer-metal Complexes

The oxidative polycondensation and optimum reaction conditions of N-2-aminopyridinylsalicylaldimine using air oxygen, H₂O₂ and NaOCl were determined in an aqueous alkaline solution between 40–90°C. Oligo-N-2-aminopyridinylsalicylaldimine (OAPSA) was characterized by using ¹H-NMR, FT-IR, UV-vis and elemental analysis. N-2-aminopyridinylsalicylaldimine was converted to oligomer by oxidizing in an aqueous alkaline medium. The number average molecular weight (M _n), weight average molecular weight (M _w) and polydispersity index (PDI) values were found to be 7487 gmol^–1, 7901 gmol^–1 and 1.06, respectively. According to these values, 70% of N-2-aminopyridinylsalicylaldimine turned into oligo-N-2-aminopyridinylsalicylaldimine. During the polycondensation reaction, a part of the azomethine (–CH=N–) groups oxidized to carboxylic (–COOH) group. Besides, the structure and properties of oligomer-metal complexes of oligo-N-2-aminopyridinyl salicylaldimine (OAPSA) with Cu (II), Ni (II), and Co (II) were studied by FT-IR, UV-vis DTA, TG and elemental analysis. Anti-microbial activities of the oligomer and its oligomer-metal complexes have been tested against C. albicans, L. monocytogenes, B. megaterium, E. coli, M. smegmatis, E. aeroginesa, P. fluorescen and B. jeoreseens. Also, according to the TG and DTA analyses, oligo-N-2-aminopyridinylsalicylaldimine and its oligomer-metal complexes were found to be stable thermo-oxidative decomposition. The weight loss of OAPSA found to be 20%, 50% and 98% at 350°C, 535°C and 1000°C, respectively.     

Synthesis,Characterization and Catalytic Activities of Palladium(II) Nitroaryl Complexes

Two palladium(II) nitroaryl complexes trans-[bromo(p-nitrophenyl)bis(triphenylphosphine)palladium(II)] 1 and trans-[bromo(2,4-dinitrophenyl)bis(triphenylphosphine)palladium(II)] 2 have been synthesized. The complexes were characterized by FTIR and NMR (¹H, ¹³C and ³¹P) spectroscopy and elemental analysis. The molecular structure of complex 2, as confirmed by X-ray crystallography, reveals that the Pd atom and its neighboring groups (two PPh₃, Br and phenylene group) lie in a slightly distorted square plane. In the UV–Vis spectra of the complexes 1 and 2, the palladium to aryl charge transfer bands were observed. The emission peaks from the singlet excited states (S₁ → S₀) were observed in the photoluminescence spectra of the complexes. The thermal stability of the complexes has been studied by thermal gravimetric analysis (TGA). TGA data showed that both complexes are thermally stable up to 200 °C, and complex 1 is more stable than 2. The catalytic efficiency of the new palladium(II) complexes was studied as demonstrated using the Sonogashira coupling reactions with good yields. The experimental results suggest that the Sonogashira coupling reactions can be performed at moderate temperature (50 °C) using these new palladium(II) complexes as catalysts.     

Homonuclear tris-dithiocarbamato ruthenium(III) complexes as single-molecule precursors for the synthesis of ruthenium(III) sulfide nanoparticles

Tris(N-phenyldithiocarbamato) ruthenium(III) complexes, [Ru(L¹)₃] (1); tris(N-(4-methylphenyl)dithiocarbamato)) ruthenium(III), [Ru(L²)₃] (2); and tris(N-(4-methoxyphenyl)dithiocarbamato)) ruthenium(III), [Ru(L³)₃] (3) were synthesized and characterized by elemental analysis, thermogravimetric analysis, FTIR, UV–VIS and NMR spectroscopy. TGA analyses show major degradation of all complexes in the range 120–350°C, leading to the formation of residual weight corresponding to ruthenium (III) sulfides. The ¹H-NMR spectra of the ligands and complexes are in agreement with the proposed structures. FTIR studies confirmed that the ligands coordinate the Ru³⁺ ion in a bidentate chelating mode. The complexes were thermolysed at 180°C to prepare hexadecylamine-capped Ru₂S₃ nanoparticles. Powder X-ray diffraction patterns revealed the formation of hexagonal-phase Ru₂S₃ nanoparticles with average crystallite sizes ranging from 8.3 to 9.5?nm. TEM images showed the crystalline clusters with shapes ranging from square to hexagonal, while SEM images elucidated that the particles were agglomerated. Energy-dispersive X-ray spectra confirmed the presents of Ru₂S₃ nanoparticles.     

Separation of Pt(IV), Pd(II), Ru(III), and Rh(III) from chloride medium using liquid–liquid extraction with mixed imidazolium-based ionic liquids

A reasonable project was presented for the extraction and separation of Pt(IV), Pd(II), Ru(III), and Rh(III) from the mixed imidazolium-based ionic liquids (ILs) [C₆mim]Cl, [C₆mim][NTf₂], and [C₆mim][DDTC]. Pt(IV) was first separated from other three platinum group metals with a mixture of [C₆mim]Cl and [C₆mim][NTf₂]. Then, separation of Pd(II) and Ru(III) from Rh(III) was realized by changing the concentration of [C₆mim][DDTC]. Back-extraction of Pt(IV), Pd(II), and Ru(III) from loaded hydrophobic phase and the recovery of Rh(III) in aqueous phase were also investigated. Mechanisms between Pd(II)/Ru(III) and [C₆mim][DDTC] were further explored using ultraviolet spectrophotometry (UV-Vis), infrared spectrophotometry (FTIR), the method of continuous variations, ab initio quantum chemical studies, and X-ray crystallographic analysis. The results afford more directions for extracting and separating metals by introducing devisable functionalized group into ILs.     

Promising Antifungal and Antibacterial Agents Based on 5-Aryl-2,2′-bipyridines and Their Heteroligand Salicylate Metal Complexes: Synthesis,Bioevaluation, Molecular Docking

A series of new 5-aryl-2,2′-bipyridines and their (polyfluoro)salicylate complexes of Cu(II), Co(II) and Mn(II) were synthesized. Their antimicrobial activity was evaluated in vitro against six strains of Trichophytons, E. floccosum, M. canis, C. ablicans and Gram-negative bacteria N. gonorrhoeae. Among azo-ligands, Ph-bipy and Tol-bipy showed promising antifungal activity (minimum inhibitory concentration (MIC)<0.8–27 μM). Their antifungal action was found can be realized via binding Fe(III) ions. Tol-bipy suppressed growth of Gram-positive bacteria S. aureus, S. aureus MRSA and their monospecies biofilms (MIC 6–16 μM). Using molecular docking, the anti-staphylococcal action mechanism based on the inhibition of S. aureus DNA gyrase GyrB was proposed for the lead compounds. Among metal complexes, Cu(II) and Mn(II) complexes based on tetrafluorosalicylic acid and Tol-bipy or Ph-bipy had the high antifungal activity (MIC<0.24–32 μM). Mn(SalF₄−2H)₂(Tol-bipy)₂] suppressed the growth of seven Candida strains at MIC 12–24 μM. [Cu(Sal−2H)(Ph-bipy)] and [Cu(SalF₃−2H)(Ph-bipy)₂] showed the promising anti-gonorrhoeae activity (MIC 4.2–5.2 μM). (Cu(SalF_n−2H)(Tol-bipy)₂], [Cu(SalF₄−2H)(Ph-bipy)₂] and [Cu(SalF₃−2H)(Ph-bipy)₂]) were found active against the bacteria of S. aureus, S. aureus MRSA and their biofilms (MIC 2.4–41.4 μM). The most active compounds were tested for toxicity in vitro against human embryonic kidney (HEK-293) cells and in vivo experiments with CD-1 mice.