Bidentate Chelating Research Articles

Nicotinamide, acetate and their two new complexes with Zn(II) and Cd(II)

Two new complexes of Zn(II) and Cd(II) with acetate and nicotinamide as mixed ligands were synthesized and characterized. The Zn(II) complex is mononuclear, [Zn(ac)2(NA)2] (1), while the Cd(II) is a dinuclear one, [Cd2(ac)4(NA)4].2H2O (2), where ac = acetate and NA = nicotinamide. The compounds were characterized by means of single-crystal X-ray diffraction, FTIR, 1H NMR, 13C NMR spectroscopy, thermal analysis and elemental analysis. The geometry of the metal ion is distorted tetrahedral for Zn(II) and distorted pentagonal bipyramid geometry for Cd(II). In the dinuclear complex, each metal ion is coordinated by three acetate groups, but there are two different types of coordination modes for the acetate ligands: bidentate chelating and bridging bidentate chelating.

Chemotherapeutic Activities of New η6-p-Cymene Ruthenium(II) and Osmium(II) Complexes with Chelating SS and Tridentate SNS Ligands.

A series of new chelating bidentate (SS) alkylimidazole-2-thione-Ru(II)/Os(II) complexes (3ai, 3aii, 3aiii, 3bii/4aiii, 4bi, 4bii), and the tridentate (SNS) pyridine-2,6-diylimidazole-2-thione-Ru(II)/Os(II) complexes (5bi, 5civ/6bi, 6ci, 6civ) in the forms [MII(cym)(L)Cl]PF6 and [MII(cym)(L)]PF6 (M = Ru or Os, cym = η6-p-cymene, and L = heterocyclic derivatives of thiourea) respectively, were successfully synthesized. Spectroscopic and analytical methods were used to characterize the complexes and their ligands. Solid-state single-crystal X-ray diffraction analyses revealed a "piano-stool" geometry around the Ru(II) or Os(II) centers in the respective complexes. The complexes were investigated for in vitro chemotherapeutic activities against human cervical carcinoma (HeLa) and the non-cancerous cell line (Hek293) using the MTT assay. The compounds 3aii, 5civ, 5bi, 4aiii, 6ci, 6civ, and the reference drug, 5-fluorouracil were found to be selective toward the tumor cells; the compounds 3ai, 3aiii, 3bii, 4bi, 4bii, and 6bi, which were found not to be selective between normal and tumor cell lines. The IC50 value of the tridentate half-sandwich complex 5bi (86 ± 9 μM) showed comparable anti-proliferative activity with the referenced commercial anti-cancer drug, 5-fluorouracil (87 ± 15 μM). The pincer (SNS) osmium complexes 6ci (36 ± 10 μM) and 6civ (40 ± 4 μM) were twice as effective as the reference drug 5-fluorouracil at the respective dose concentrations. However, the analogous pincer (SNS) ruthenium complex 5civ was ineffective and did not show anti-proliferative activity, even at a higher concentration of 147 ± 1 μM. These findings imply that the higher stability of the chelating (SS) and the pincer (SNS) ligand architectures in the complexes improves the biological (anti-proliferative) activity of the complexes by reducing the chance of ligand dissociation under physiological conditions. In general, the pincer (SNS) osmium complexes were found to be more cytotoxic than their ruthenium analogues, suggesting that the anti-proliferative activity of the imidazole-2-thione-Ru/Os complexes depends on the ligand's spatial coordination, the nature of the metal center, and the charge of the metal complex ions.

Re-exploration of tetrahydro-β-carboline scaffold: Discovery of selective histone deacetylase 6 inhibitors with neurite outgrowth-promoting and neuroprotective activities

Histone deacetylase 6 (HDAC6) has drawn more and more attention for its potential application in Alzheimer's disease (AD) therapy. A series of tetrahydro-β-carboline (THβC) hydroxamic acids with aryl linker were synthesized. In enzymatic assay, all compounds exhibited nanomolar IC50 values. The most promising compound 11d preferentially inhibited HDAC6 (IC50, 8.64 nM) with approximately 149-fold selectivity over HDAC1. Molecular simulation revealed that the hydroxamic acid of 11d could bind to the zinc ion by a bidentate chelating manner. In vitro, 11d induced neurite outgrowth of PC12 cells without producing toxic effects and showed obvious neuroprotective activity in a model of H2O2-induced oxidative stress.

Discovery of Tetrazolamide-benzimidazol-2-ones as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors.

4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is one of the most valuable herbicide targets due to its unique biological functions. In search of HPPD inhibitors with promising biological performance, we designed and synthesized a series of novel tetrazolamide-benzimidazol-2-ones using a structure-based drug design strategy. Among the synthesized compounds, 1-(2-chlorobenzyl)-3-methyl-N-(1-methyl-1H-tetrazol-5-yl)-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-4-carboxamide, 25, IC50 = 10 nM, was identified to be the most outstanding HPPD inhibitor, which showed more than 36-fold increased Arabidopsis thaliana HPPD (AtHPPD) inhibition potency than mesotrione (IC50 = 363 nM). Our AtHPPD-25 complex indicated that one nitrogen atom on the tetrazole ring and the oxygen atom on the amide group formed a classical bidentate chelation interaction with the metal ion, the benzimidazol-2-one ring created a tight π-π stacking interaction with Phe381 and Phe424, and some hydrophobic interactions were also found between the ortho-Cl-benzyl group and surrounding residues. Compound 32 showed more than 80% inhibition against all four tested weeds at 150 g ai/ha by the postemergence application. Our results indicated that the tetrazolamide-benzimidazol-2-one scaffold may be a new lead structure for herbicide discovery.

Spectrophotometric Determination and Biological Activity Study of Zn(II) using a Newly Synthesized Azo Reagent Derivative from 4,5-bis(4-methoxyphenyl) Imidazole

A rapid and simple spectrophotometric method was submitted for Zn(II) determination using (E)-2-(4,5-bis(4-methoxyphenyl)-1H-imidazole-4-yl) diazenyl) benzoic acid as an analytical reagent. The suggested method is based on the chelation reaction between Zn(II) and the bidentate chelation ligand with a mole ratio of 1:2 (metal:ligand) with octahedral geometry. The maximum absorption of the formed violet complex was 560 nm, the linearity was in the concentration range of 0.5-15.0 µg mL-1. The relative standard deviation (n =10) was 0.149%. The interfering effect of diverse cations and anions was tested. To clarify the biological efficacy of the synthesized Zn(II) complex, an in vitro biological activity study was carried out against four kinds of bacterial strains, and the results showed promising inhibition activity.

Coordination compounds of indium, gadolinium, and erbium nitrates with low urea content

Objectives. To date, compounds of rare earth nitrates with urea in a ratio of 1:4 and indium in a ratio of 1:6 have been synthesized and structurally characterized. However, there is a lack of research into similar compounds having a lower urea content. The purpose of this work was to continue the search for regularities of structure formation for complexes of various elements with urea.Methods. Novel coordination compounds were synthesized and characterized by powder- and single-crystal X-ray diffraction analysis, as well as infrared spectroscopy.Results. The interaction of indium, gadolinium and erbium nitrates with urea (Ur) in an aqueous solution under conditions of ligand deficiency produces the previously unknown coordination compounds cis-[In(Ur)4(NO3)2]NO3, [Gd(H2O)2(Ur)2(NO3)3], and [Er(H2O)2(Ur)(NO3)3]. The indium complex is shown to have an ionic structure, whereas the gadolinium and erbium complexes have a molecular structure. In the indium complex, the coordination number is 6; the cation has an octahedral structure; it involves two cis-arranged monodentate nitrate groups and four monodentate urea molecules. The coordination number of gadolinium is 10; here, the coordination polyhedron is a distorted pentagonal bipyramid at the vertices of which there are two water molecules, while in the internal polygonal base there are two monodentate urea molecules and three bidentate chelating nitrate groups oriented perpendicular to the polygonal base of the bipyramid. The coordination number of erbium is 9; the coordination polyhedron is a distorted tricapped trigonal prism.Conclusions. In contrast with the gadolinium complex, one urea molecule is coordinated in the erbium complex instead of two, decreasing the coordination number from 10 to 9. In the indium complex cation, the coordination number is 6; unlike the gadolinium and erbium complexes, the cation does not contain water, and the nitrate groups are monodentate.

Modifying Surface Termination by Bidentate Chelating Strategy Enables 13.77% Efficient Kesterite Solar Cells.

Surfaces display discontinuities in the kesterite-based polycrystalline films can produce large defect densities, including strained and dangling bonds. These physical defects tend to introduce electronic defects and surface states, which can greatly promote nonradiative recombination of electron-hole pairs and damage device performance. Here, an effective chelation strategy is reported to suppress these harmful physical defects related to unterminated Cu, Zn, and Sn sites by modifying the surface of Cu2ZnSn(S,Se)4 (CZTSSe) films with sodium diethyldithiocarbamate (NaDDTC). The conjoint theoretical calculations and experimental results reveal that the NaDDTC molecules can be coordinate to surface metal sites of CZTSSe films via robust bidentate chelating interactions, effectively reducing surface undercoordinated defects and passivating the electron trap states. Consequently, the solar cell efficiency of the NaDDTC-treated device is increased to as high as 13.77% under 100mW cm-2 illumination, with significant improvement in fill factor and open-circuit voltage. This surface chelation strategy provides strong surface termination and defect passivation for further development and application of kesterite-based photovoltaics.

Contrasting a series of bidentate amido phosphine oxide, sulfide, or selenide ligands and complexes of dimethyl aluminum and indium.

A series of EP(V)-imine phosphine-imine ligands (Dipp-NC(CH3)-(CH2)-PE(Ph2)) (Dipp = 2,6-diisopropylphenyl, E = O, S, Se) and corresponding dimethyl aluminum and indium complexes were prepared and characterized using multi-nuclear NMR spectroscopy and SC-XRD. Solution-state 1H and 31P NMR spectroscopy indicate a mixture of isomers in solution (C6D6, CDCl3, and CD3CN). Solid state structures of both the imine and (E)-enamine isomers of the oxygen-based ligand have been observed. These three ligands (L) were then deprotonated with M(CH3)3 (M = Al or In), with methane loss forming a 6-membered ring via bidentate chelation ((κ2-L)M(CH3)2). The indium/oxide complex also crystallized as a 12-membered ring.

Enantioselective dearomative formal (3+3) cycloadditions of bicyclobutanes with aromatic azomethine imines: access to fused 2,3-diazabicyclo[3.1.1]heptanes

We present the first enantioselective dearomative (3+3) cycloadditions of bicyclobutanes (BCBs) utilizing a chiral Lewis acid catalyst and bidentate chelating BCB substrates.

Enhanced protonation ability of covalent organic frameworks via N,O-bidentate chelation for photocatalytic H2 evolution.

Inspired by the bidentate coordination chemistry of metal ions, we incorporated hydroxyl (OH) and methoxy (OMe) groups into the skeleton of imine-linked COFs to improve their protonation ability via intramolecular hydrogen bonds (O-H⋯NC). In comparison with the pristine COFs possessing monodentate nitrogen coordination sites, OH and OMe functionalized COFs with (N,O)-bidentate chelating sites exhibited up to 13.8 times faster photocatalytic hydrogen evolution rates (HERs).

Systematics of stable copper and silver clusters protected by small bite chelating bidentate sulfur and selenium ligands related to their polyhedral cavities: analogies to aliphatic compounds and three-dimensional spherical aromatic systems.

Silver and copper clusters capped by external chelating dithiolate ligands can be classified according to the cavities in their central coinage metal polyhedra. Silver clusters composed exclusively of fused tetrahedra are analogous to simple saturated organic compounds. The only interstitial atom that can be fit into an Ag4 tetrahedron is hydrogen. Silver polyhedra with larger trigonal prismatic or cubic cavities, including highly distorted cubic cavities, can accommodate halide and chalcogenide anions. The still larger 12-vertex icosahedral and cuboctahedral coinage metal cavities can accommodate oxoanions of the types SO32- and SO42- and their heavier congeners or alternatively interstitial coinage or platinum group metals leading to central M'@M12 units. Copper clusters with central cuboctahedra and silver clusters with central icosahedra possessing interstitial metal atoms approximate sphericality and provide examples of electron-rich metal superatoms with an average metal oxidation state of less than +1. Such copper cluster superatoms have two extra electrons corresponding to a filled 1S2 superatomic orbital. The silver cluster superatoms are electron richer with eight extra electrons corresponding to filled 1S2 + 1P6 superatomic orbitals. In these silver clusters seven or eight faces of the central Ag12 icosahedron are capped by additional silver atoms in order to provide these additional electrons.

Development of ruthenium complexes with S-donor ligands for application in synthesis, catalytic acceptorless alcohol dehydrogenation and crossed-aldol condensation.

The reaction of [Ru(dmso)4Cl2] with a potassium salt of four xanthate (RO-C(S)S-; R = Me, Et, iPr and tBu) ligands (depicted as Ln; n = 1-4) in hot methanol afforded a group of mixed-ligand complexes of type [Ru(Ln)2(dmso)2]. The crystal structures of all the four complexes have been determined, which show that the xanthate ligands are bound to the metal center forming four-membered chelates and dmso is coordinated through sulfur and they are mutually cis. The relative thermodynamic stability of this cis and the other possible trans-isomers of these complexes has been assessed with the help of DFT calculations, which have revealed that the cis-isomer is the more stable isomer. The coordinated dmso in the [Ru(Ln)2(dmso)2] complexes could be easily displaced by chelating bidentate ligands (depicted as L') to furnish complexes of type [Ru(Ln)2(L')], as demonstrated through isolation of two such complexes, viz. [Ru(L3)2(bpy)] and [Ru(L2)2(phen)] (bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline). The crystal structure of [Ru(L3)2(bpy)] has been determined and the structure of [Ru(L2)2(phen)] has been optimized by the DFT method. The electronic spectra of the four [Ru(Ln)2(dmso)2] complexes and the two derivatives ([Ru(Ln)2(L')]; n = 3, L' = bpy; n = 2, L' = phen), recorded in dichloromethane solutions, show intense absorptions spanning the visible and ultraviolet regions, which have been analyzed by the TDDFT method. The [Ru(Ln)2(dmso)2] complexes are found to serve as efficient catalyst precursors for the acceptorless dehydrogenation of 2-propanol followed by crossed-aldol condensation with substituted benzaldehydes (and related aldehydes), using tert-butoxide as the co-catalyst, producing dibenzylideneacetone derivatives in good yields.

Structural consequences in differently substituted haloarylcarboxylates and non-covalent interactions on crystal packing and biological efficacy of copper(II) complexes with N,N,N′,N′-tetramethylethylenediamine N-donor ligand

In this work, we reported four new copper(II) halo-benzoate complexes (2-chloro-4-nitrobenzoate (2-Cl-4-NO2-BZ), 3,5-DICBZ, 2-chloro-5-nitrobenzoate (2-Cl-5-NO2-BZ), 3,5-difluoro benzoate (3,5-DIFBZ), and 3,5-dichlorobenzene (3,5-DICBZ) respectively in complexes 1–4) with N,N,N’,N’- tetramethylethylene diamine (temed) N-donor ligand in order to study the interesting coordination features and biological evaluation of such complexes under ambient reaction conditions. All the complexes 1–4 were characterized by elemental analyses, and spectroscopic techniques, including FT-IR, UV–vis, and EPR etc. Single crystal X-ray structure determination (SCXRD) of complexes revealed the distorted octahedral geometry in all complexes. Notably, the halobenzoate ligands exhibited a bidentate chelation mode in complexes 1 and 2, while they showed a monodentate mode in complex 3. In complex 4, the carboxylate ligand exhibited both monodentate as well as bidentate coordination. Furthermore, detailed packing analyses of complexes 1–4 highlighted the significance of halogen bonding in lattice stabilization besides hydrogen bonding and π∙∙∙π interactions as evidenced by Hirshfeld surface analyses and crystal analysis. Moreover, packing analyses displayed that complex 1 exhibited a layered or wave-like arrangement, while complex 2 featured a helical arrangement supported by a supramolecular halogen-bonded network guided by Cl∙∙∙O interactions. Complex 3 displayed a zig-zag layered arrangement with a stacking topology, and Complex 4 showcased a ribbon-like arrangement stabilized by F∙∙∙F and Cl∙∙∙Cl halogen bonding interactions. Furthermore, sigma hole on halogen atoms has also been examined (which play an important role in halogen bonding) by electrostatic-potential isosurfaces. In order to exploit the biological efficacy of complexes 1–4 owing to the inherent biological activity of copper metal, molecular docking analyses against gram +ve bacteria i.e. S. epidermidis (PDB ID; 8DO6), B. subtilis (1QD9), as well as two gram -ve bacteria, namely, P. aeruginosa (5WZE) and S. dysenteriae (1DM0), have also been carried out. Interestingly, values of docking scores and inhibition constant of all complexes 1–4 (with a maximum binding score (inhibition constant) of -9.8 kcal/mol (0.063 µMol) in 1 against 8DO6 and 1DM0) revealed higher biological efficacy than that of standard drugs.

Ligational behavior of bidentate NO-donor, 2-(((1H-1,2,4-triazol-5-yl)imino)methyl)-4-(o-tolyldiazenyl)phenol towards VO2+, Fe3+, Ru3+, Co2+, Mn2+, Ni2+, Cu2+ Zn2+ and ions preparation, experimental, theoretical characterization, and microbicidal investigation

Novel bidentate chelator, 2-(((1H-1,2,4-triazol-5-yl)imino)methyl)-4-(o-tolyldiazenyl)phenol was employed for designing and preparation of transition metallic complexes. The synthetics were characterized based on various analytical, spectral, and theoretical tools. Based on the various analysis data, the azo-Schiff base chelator (H2L) linked with metallic cations as a neutral/uni-negative bidentate chelator via the protonated/deprotonated hydroxyl oxygen and azomethine nitrogen atoms adopted a distorted octahedral, tetrahedral, or square planar geometry. The mass spectroscopy confirmed that the molecular weights of azo-Schiff base and some of its complexes closely match with that of the estimated m/z values. Additionally, the structure of the azo-Schiff base ligand and some metallic complexes were studied by Density functional theory (DFT) calculations to assess the molecular orbitals (LUMO&HOMO) as well as the molecules electrostatic potential (MEP) to complete the picture. The synthetics were evaluated for their in vitro activity against Escherichia coli, Aspergillus niger, and Bacillus subtilis. According to this research, unbound ligand molecules are inactive while their metallic complexes have low to moderate activity.

The [Zn(NH3)4]2+ reactions with quinaldinate or pyrazinoate: A ready synthetic route to zinc(II) coordination polymers?

The reaction of [Zn(NH3)4]2+ in aqueous ammonia solution with quinaldinic acid (quinoline-2-carboxylic acid) gave a mononuclear heteroleptic ammine/quinaldinate complex with the [Zn(quin)2(NH3)] composition. The introduced secondary ligand adopted the usual N,O-bidentate chelating coordination. In the analogous reaction with pyrazinoic acid (pyrazine-2-carboxylic acid), complete substitution of ammonia with pyrazionate and water was observed. A mixture of two compounds formed: a mononuclear and already known [Zn(pyraz)2(H2O)2] and a novel one-dimensional (1D) coordination polymer [Zn(pyraz)2(H2O)]n. X-ray structure analysis revealed the pyrazinoate ligands in [Zn(pyraz)2(H2O)]n in two binding modes, in a bidentate chelating coordination and in a tridentate bridging coordination. The bridging pyrazinoate has engaged in binding three out of four donors: a carboxylate oxygen and both nitrogen atoms. A detailed presentation of the structure of [Zn(pyraz)2(H2O)]n and its comparison with the structures of related compounds are given below.

Synthesis, crystal structure and Hirshfeld surface analysis of the tetra-kis complex NaNdPyr4(i-PrOH)2·i-PrOH with a carbacyl-amido-phosphate of the amide type.

The tetra-kis complex of neodymium(III), tetra-kis-{μ-N-[bis-(pyrrolidin-1-yl)phos-phor-yl]acet-am-id-ato}bis(pro-pan-2-ol)neodymiumsodium pro-pan-2-ol monosol-vate, [NaNd(C10H16Cl3N3O2)4(C3H8O)2]·C3H8O or NaNdPyr4(i-PrOH)2·i-PrOH, with the amide type CAPh ligand bis(N,N-tetra-methylene)(tri-chloro-acetyl)phos-phoric acid tri-amide (HPyr), has been synthesized, crystallized and characterized by X-ray diffraction. The complex does not have the tetra-kis-(CAPh)lanthanide anion, which is typical for ester-type CAPh-based coordin-ation compounds. Instead, the NdO8 polyhedron is formed by one oxygen atom of a 2-propanol mol-ecule and seven oxygen atoms of CAPh ligands in the title compound. Three CAPh ligands are coordinated in a bidentate chelating manner to the NdIII ion and simultaneously binding the sodium cation by μ2-bridging PO and CO groups while the fourth CAPh ligand is coordinated to the sodium cation in a bidentate chelating manner and, due to the μ2-bridging function of the PO group, also binds the neodymium ion.

Lewis Acid-Base Adducts of α-Amino Acid-Derived Silaheterocycles and N-Methylimidazole

In chloroform solution, the reaction of bis(tert-butylamino)dimethylsilane ((tBuNH)2SiMe2) and an α-amino acid (α-amino isobutyric acid, H2Aib; D-phenylglycine, H2Phg; L-valine, H2Val) in the presence of N-methylimidazole (NMI) gave rise to the formation of the pentacoordinate silicon complexes (Aib)SiMe2-NMI, (Phg)SiMe2-NMI and (Val)SiMe2-NMI, respectively. Therein, the amino acid building block was a di-anionic bidentate chelator at the silicon atom. In solution, the complexes were involved in rapid coordination–dissociation equilibria between the pentacoordinate Si complex (e.g., (Aib)SiMe2-NMI) and its constituents NMI and a five-membered silaheterocycle (e.g., (Aib)SiMe2), as shown by 29Si NMR spectroscopy. The energetics of the Lewis acid-base adduct formation and the competing solvation of the NMI molecule by chloroform were assessed with the aid of computational methods. In CDCl3 solution, deuteration of the silaheterocycle NH group proceeded rapidly, with more than 50% conversion within two days. Upon cooling to −44 °C, the chloroform solvates of the adducts (Aib)SiMe2-NMI and (Phg)SiMe2-NMI crystallized from their parent solutions and allowed for their single-crystal X-ray diffraction analyses. In both cases, the Si atom was situated in a distorted trigonal bipyramidal coordination sphere with equatorial Si–C bonds and an equatorial Si–N bond (the one of the silaheterocycle). The axial positions were occupied by a carboxylate O atom of the silaheterocycle and the NMI ligand’s donor-N-atom.

Antibacterial, antifungal, DNA interactions, and antioxidant evaluation of Cu(II) Co(II), Ni(II), Mn(II) and UO2(II) mixed ligand metal complexes: Synthesis, characterization and molecular docking studies

The current work was designed to prepare novel 1:1:1 Metal (M): primary ligand (HL1): co-ligand (HL2) complexes; [Cu(L1)(L2)(OH2)2] (1), [Co(L1)(L2)]H2O (2), [Ni(L1)(L2)(OH2)2] 0·.75H2O (3) and [Mn(L1)(L2)(OH2)2] 4·.5H2O (4) and [UO2(L1)(L2)] (5) from ligands 7-Formyl-8-hydroxyquinoline (oxine) (HL1), 2-aminophenol (HL2) and characterized by analytical and spectroscopic techniques. FTIR, mass spectra, ESR techniques, elemental analysis, and thermal analysis were used to characterize the newly formed complexes. The results of the elemental analysis show the formation of [HL1:M:HL2] complexes. The ligands act as a mononegative bidentate chelating agent coordinating through C = O, NH2 and two OH groups by replacement of a proton from the latter groups. The molecular docking between the protein receptors and the ligand (HL1), ligand (HL2) and its mixed ligand metal complexes (1–5) was studied. The interface between HL2, complexes and calf thymus DNA (CT-DNA) displays hypochromism behavior. The binding value constant (Kb) are calculated and found to be 5.29 × 103, 8.49 × 104, 2.45 × 105, 2.96 × 104 and 1.16 × 104, 3.08 × 104 M−1 for HL2 and its mixed ligand metal complexes (1–5), respectively. Antimicrobial properties of ligands and the synthesized complexes were also screened versus G + ve bacteria (S. aureus and B. cereus), G-ve bacteria (K. pneumoniae, Pseudomonas sp. and E. coli, and fungi (F. oxysporum, A. niger, and C. albicans). The obtained results revealed the strong antimicrobial action of metal complexes with MIC, MBC and MFC values ranging from 5 to 45 µg/ml. HL1 showed higher antimicrobial and antioxidant activities than HL2 and major of the prepared metal complexes. All metal mixed ligand complexes inhibited the multidrug-resistant bacterium; Klebsiella pneumoniae compared to the standard antibiotic, penicillin G. Also, all metal mixed ligand complexes showed potent antifungal activities against both Aspergillus niger and Candida albicans.

Nine Cd2+ complexes containing 3,5-dimethylpyrazole and carboxylic acids: Synthesis, spectroscopic and crystallographic characterization

Nine mixed-ligand Cd2+ complexes of [Cd(Hdmpz)2(bcaa)2] (1) (Hbcaa = 3-(benzylcarbamoyl)-acrylic acid), Cd4(Hdmpz)4(tcba)8(2) (Htcba = 2,4,6-trichlorobenzoic acid), [Cd(Hdmpz)(napa)2] (3) (Hnapa = 1-naphthoic acid), [Cd(Hdmpz)2(cnba2] (4) (Hcnba = 2-chloro-4-nitrobenzoic acid), Cd(Hdmpz)2(hmba)2 · H2O (5) (Hhmba = 4-hydroxy-3-methoxybenzoic acid), [Cd(Hdmpz)2(msal)2] (6) (Hmsal = 3-methylsalicylic acid), [Cd(Hdmpz)2(dbta)(H2O)] · 2H2O (7) (H2dbta = dibenzoyltartaric acid), [Cd(Hdmpz)4(tpda)] (8) (H2tpda = 2,5-thiophenedicarboxylic acid) and [Cd3(Hdmpz)6(btca)2(H2O)4] · 2H2O (9) (H3btca = 1,2,4-benzenetricarboxylic acid) were synthesized and formulated by EA, IR spectra + SCXRD, their TGA were also conducted.The SCXRD reports indicated that the complexes exhibit mononuclear to tetranuclear structures with octahedral geometry at the Cd2+. The Hdmpzs in all examples are coordinated only through the monodentate fashion with its neutral N. The carboxylate at 8 displays only as unidentate coordination, while the ones in 1, 4 and 5–7 take the chelating bidentate coordination mode. The CO2− at 2–3 adopts both the chelating bridging tridentate and bismonodentate coordination fashion. 9 contains both unidentate and bidentate chelating coordinate CO2−. There all existed the NH···O H-bond from the NH of the Hdmpz. 6 has the intramolecular OH···O H-bond from the ortho phenol and the CO2−, resulting the S11(6) pattern. 5, 7 and 9 have the intermolecular OH···O H-bond. 2, and 4–6 bear only the intermolecular NH···O H-bond; 3, and 8–9 have only the intramolecular NH···O H-bond. Compounds 1 and 7 bear both the intra- and intermolecular NH···O H-bonds.There featured intricate intra- and intermolecular classical H-bonds (NH···O/OH···O) together with CH-π/CH2-π/CH3-π, CH3-CH/CH3-CH3, CH3-C, CH-O/CH3-O, CH-Cl/CH3-Cl, Cl-O, Cl-π, O-π, OC plus OO associates which are illuminated by the X-ray crystallographic technique, tethering the discrete units into high-dimensional ordered supramolecular systems.

Boosting Zinc‐Ion Batteries with Innovative Ternary Electrolyte for Enhanced Interfacial Electrochemistry and Temperature‐Resilient Performance

AbstractThe practical application of Zn‐ion batteries (ZIBs) faces several challenges, particularly regarding poor reversibility and the reactivity of water in the electrolytes across a wide temperature range. Herein, this study presents the design of a ternary electrolyte with significant intermolecular interactions based on tetrahydrofurfuryl alcohol (THFA), H2O, and Zn(OTf)2 to address these challenges from −40 to 60 °C. The ether alcohol compound THFA effectively mitigates the side reactions about water, by disrupting and suppressing the reactivity of the dominant water‐based clusters. Through experimental and theoretical investigations, the structural and mechanistic insights of ternary solvation clusters are uncovered. The hydrogen‐bond‐induced interactions of THFA facilitate the participation of OTf− in solvation clusters and bidentate chelation coordination with Zn2+ ensures the formation of lean‐water solvation clusters. Furthermore, the interfacial electrochemistry on the Zn surface is also regulated to exhibit a preferential layer‐by‐layer (0 0 2) oriented deposition with a stable solid electrolyte interface (SEI). As a result, The Zn||VO2 battery using ternary electrolyte maintains a capacity of 237.5 mAh g−1 with an 86.71% retention after 500 cycles at 60 °C and 3 A g−1, while it exhibits stable cycle even at −40 °C over 200 cycles with almost no capacity decrease.