Mixed Ligand Chelates Research Articles

Design, synthesize, physicochemical characterization, nonlinear optical properties structural elucidation, biomedical studies, and DNA interaction of some new mixed ligand complexes incorporating 4,6‐dimethylpyrimidine derivative and imidazole ligand

This study was planned to prepare new mixed ligand chelates derived from N‐(4,6‐dimethylpyrimidin‐2‐yl)‐3a,4,5,6,7,7a‐hexahydro‐1H‐benzimidazol‐2‐amine (BIP), and imidazole (I). They identified through CHN study, spectroscopic (NMR, FT‐IR, and UV–Vis), conductivity, magnetic susceptibility, mass analysis, and thermal analysis. Correlation between all results exposed that the BIP ligand performed as a bi‐dentate ligand through NN donation locations, where the co‐ligand shows as N–H monodentate. The optimization for the studied chelates led to the formation of distorted octahedral geometry for BIPICu and BIPIVO chelates, distorted (tetrahedral and square planar) geometry for BIPIAg and BIPIPd chelates, respectively, around the metal salt. The B3LYP level, B3LYP/6‐311G** level for the free ligand, and B3LYP/6–311G**‐LANL2DZ functional level for the solid chelates were used in density functional theory (DFT) calculations. The findings showed that DFT calculations produce conclusions that are consistent with those of the experiments. The resulting compounds' nonlinear optical properties were examined by calculating the hyperpolarizability (β) and molecular polarizability (α) parameters, which gave rise to several unexpected optical properties for the synthesized compounds. Using the agar well diffusion method, the antimicrobial activity of the produced compounds was experimentally confirmed against a subset of G+ and G− bacteria. To ascertain how these substances attach to the targeted protein binding sites, a molecular docking mechanism between the microbially resistant chelates and their suppressed microbial protein pocket receptors was investigated. Also, DNA binding estimated for studied structures was tested by electronic absorption spectrum, viscosity estimation, and gel electrophoresis. Data proposed that all tested compounds link with DNA using an intercalation, electrostatic, and covalent binding mechanism. Moreover, antioxidant performance for studied compounds was governed by radical scavenging techniques in vitro. In addition, an MTT assay has been worked out to explore in vitro cytotoxic impending. All the tested chelates assumed antimicrobial, antitumor, and antioxidant performances that cause them to suggest drugs.

Synthesize, structural inspection, stoichiometry in solution and DFT calculation of some novel mixed ligand complexes: DNA binding, biomedical applications and molecular docking approach

Mixed ligand chelates of Pd(II), Cu(II), VO(II), and Ag(I) with (BIP = 4,6-dimethyl-N-(octahydro-2H-benzimidazol-2-ylidene)pyrimidin-2-amine) as a main ligand and (Phen = 1, 10-phenanthroline) as a second ligand were synthesized. The recently prepared chelates were investigated through CHN analysis, (NMR, Ft-IR, Mass, and UV–Vis) spectra, magnetic moments, molar conductance, TGA, Job s methods and DFT study. The (CHN and Mass) analysis, result expose the formation of structures (1 M: 1BIP: 1Phen) chelates. The two studied ligands are established to perform in as a neutral bi-dentate approach, concluded four N2 atoms for two ligands. The study of the molar conductance indicated the non-electrolytic features for (Cu(II) and VO(II)) chelates and the electrolytic features for (Ag(I) and Pd(II)) chelates. Thermo-dynamic and Kinetics factors for various thermal degradation phases were calculated. B3LYP/LANL2DZ/6–311 g(d,p) theoretical study has been applied for estimating the MEP, FMO analysis and quantum chemical reactivity descriptors of studied molecules. Practical and computational detail reveals that BIPPCu and BIPPVO complexes possess octahedral geometry around the metal center, BIPPAg complex shows a tetrahedral configuration, and BIPPPd complex has distorted square planar geometry. In vitro anti-microbial and anti-cancer for the studied structures were applied against various strains of microbes and cancer cell lines. The results revealed that all tested chelates showed a higher activity than the free BIP. The tested complexes have been studied to antioxidant potential using DPPH study. The binding of tested chelates with DNA was studied through applying electronic absorption, gel electrophoresis as well as viscosity study, in addition to the intercalating, minor groove and electrostatic approach of DNA interacting were recommended. The studied compounds explained dynamic satisfying performing. Also, the crystal structures of DNA (PDB ID: 454D), human coronavirus Nl63 nucleocapsid protein (PDB ID: 5EPW), breast cancer protein (PDB ID: 3HB5), and Escherichia coli (PDB ID: 2VF5) was performed by molecular docking simulation. Data of docking simulation suggestions are which tested compounds have biological behavior as well as have obvious benefit in the pharmaceutical business.

Synthesis, Characterization and Antimicrobial evaluation of some mixed ligand chelates using 2-aminobenzoic acid as a secondary ligand

The present work deals with the preparation of four mixed ligand chelates that resulted from the reaction of Schiff base[coupling of 2-hydroxyacetophenone and 2,4-dinitrophenylhydrazine (HL1) and 2-aminobenzoic acid (L2)]. The Schiff base, 2-aminobenzoic acid and their mixed ligand chelates were offered to several physicochemical tools; CHN elemental analyses, molar conductivity, magnetic moments, thermogravimetric analysis, IR and 1HNMR, Basis on the obtained results, the mixed ligand chelates appeared in the 1:1:1 [M:L1:L2] ratio as found from the elemental analysis data and found to have the formulae [L1ML2(H2O)2], where M = Mn(II), Co(II) and Ni(II) ions and [L1FeL2(ONO2)(H2O)], Meanwhile, the 1:1:2[M:L1:L2] ratio is for [L1Cr(L2)2] complex, The molar conductance results revealed that the mixed ligand chelates were non-electrolytes, whereas, the magnetic moments were used to confirm the coordinating capacity of the ligands, infrared spectra displayed that the Schiff base, 2-aminobenzoic acid were bonded to the metal ions in a bidentate manner with donor sites. According to the results obtained from the electronic spectra, an octahedral structure was suggested for all the chelates. Also, the hydrated and coordinated water molecules were discussed using thermogravimetric analysis. Antimicrobial activities of the prepared compounds were tested on several types of bacteria and fungi and their activities were reported.

Synthesis and characterization of some transition and inner transition mixed ligand complexes derived from Schiff base ligand and o-aminophenol

By the condensation reaction of benzophenone with naphthalene-1,8-diamine, a bidentate NN Schiff base ligand (L) was obtained. The preparation and structural characterization of mixed ligand chelates derived from Schiff base ligand as a primary ligand and o-aminophenol (o-AP) as a secondary ligand, were also reported. The synthesized Schiff base ligand and its transition and inner transition mixed ligand chelates were characterized based on elemental analyses, FT-IR, mass, 1H-NMR, UV-Vis., molar conductivity and magnetic studies. Thermogravimetric studies were also investigated to determine the thermal stability and degradation of the metal complexes. An octahedral geometry was suggested for all complexes based on spectroscopic and magnetic studies. The surface morphology of the Schiff base ligand and Mn(II) complex confirmed their nano-size. The mass spectra of Schiff base ligand and Er(III) mixed ligand complex pointed out the fair agreement between the calculated and found values. In-vitro antimicrobial activities of Schiff base ligand, o-aminophenol and the mixed ligand complexes were investigated against different pathogenic bacterial and fungal species. The anticancer activity of the new compounds had been also studied towards breast cancer (MCF-7). Molecular docking of the Schiff base ligand was also reported.

Preparation, spectroscopic characterization and antitumor-antimicrobial studies of some Schiff base transition and inner transition mixed ligand complexes

Mixed ligand complexes of Mn(II), Ni(II), Zn(II), La(III), Er(III) and Yb(III) metal ions were prepared from bidentate Schiff base ligand (L) as a primary ligand, derived from condensation of benzophenone and 1,8-naphthylenediamine, and 1,10-phenanthroline (Phen) as a secondary ligand. The new Schiff base ligand (N1-(diphenylmethylene)naphthalene-1,8-diamine) and its mixed ligand complexes were characterized by using elemental microanalysis, conductometric measurements, magnetic susceptibility and spectroscopic studies (UV–Vis, mass spectral analysis, IR, 1H NMR and SEM). In addition, their thermal analytical (TG and DTG) behavior has been reported. Measurements of the molar conductivity of the complexes in DMF solvent pointed out the electrolytic nature of all complexes except Mn(II) and Zn(II) complexes were non electrolytes. According to the elemental analyses data, it was observed that the mixed ligand chelates had the general formulae [M(L)(Phen)Cl2]Cl.2H2O (M = La(III), Er(III) and Yb(III)), [M(L)(Phen)Cl2].H2O (M = Mn(II) and Zn(II)) and [Ni(L)(Phen)Cl(H2O)]Cl.H2O. Based on these findings, all mixed ligand complexes had octahedral geometry. The SEM image of the Schiff base ligand illustrated its rods like morphology with and average particle size of 77 nm while, the image of Ni(II) complex showed non-uniform platelets structure with some scattered rods with an average particle size of 54 nm. Considerable applications were done to ensure the biological significance of Schiff base ligand and its new mixed ligand complexes with Phen against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Bacillus subtilis) and fungal (Aspergillus flavus and Candida albicans) strains and anti-cancer activities against (MCF7 breast cancer cell line). The results obtained revealed that the complexes exhibited promising biological and anticancer activity. Moreover, molecular docking studies were applied to determine the probable binding mode among the Schiff base ligand and the active site of the crystal structure of E. coli YcbB acylated with meropenem (PDB ID: 6NTW) and breast cancer estrogen mutant L536S (PDB ID: 6SBO) receptors.

Ni(II) mixed-ligand chelates based on 2-hydroxy-1-naphthaldehyde as antimicrobial agents: Synthesis, characterization, and molecular modeling

New Ni (II) ternary chelates; based on 2-hydroxy-1-naphthaldehyde Schiff-base ligand with various N-heterocyclic co-ligands, were synthesized and characterized. Structural analysis were performed to estimate the chelates stability based on the cis- and trans- orientation around the Ni(II)-center using density functional theory (DFT) calculations. Moreover, selected quantum chemical descriptors had been computed using frontier molecular orbitals to evaluate the reactivity based on the electronic structural analysis. Pharmaceutical potential of the subject molecules have been estimated by screening the most important drug-likeness parameters. In silico investigation revealed that the target compounds could be potential bioactive drug-like molecules. Mixed-ligand effect on antimicrobial activity was in-vitro screened against pathogenic bacteria; E. coli (G−), and B. cereus (G+), as well as A. fumigatus fungi. Interestingly, presence of co-ligand in the ternary Ni (II) chelates led to higher enhancement in the antimicrobial behavior comparing with its binary one. Finally, both theoretical and experimental data were combined for generating a structure activity relationship (SAR) model that might be used for the developing of new metal chelates as antimicrobial agents.

Synthesis, characterization and biological activity of mixed ligand chelates of Ni(II) with pyridoxalthiosemicarbazone and dipeptides

AbstractThe synthesis, characterization of mixed ligand chelates of Ni(II), [NiAL] involving Pyridoxalthiosemicarbazone (A) and dipeptides (L) viz., glycyl‐glycine (gly‐gly), glycyl‐L‐leucine (gly‐leu), glycyl‐L‐tyrosine (gly‐tyr) and glycyl‐L‐valine (gly‐val) and their biological activities have been studied. The complexes were characterized based on their elemental analysis, LC‐MS, IR, UV‐Vis spectral studies, magnetic moment, molar conductance and thermal analysis. The mixed ligand complexes were formed with 1:1:1 (Ni:A:L) ratio. The molar conductance data reveal the non‐electrolytic nature of the metal chelates. IR spectra show that the ligands are coordinated to the metal ion in a tridentate manner, involving O,N,S and O,N,N donor sites of ligands, A and L respectively. Based on the analytical data, octahedral geometry has been proposed for the metal complexes. DNA binding properties of the complexes have been investigated by UV‐Vis and fluorescence spectroscopy and also by viscosity measurements. The obtained results indicate that the complexes bind to DNA through intercalation mode, which is further validated by molecular docking studies. The hydrolytic cleavage of the pBR322 DNA from supercoiled to nicked form, by the metal complexes was investigated by gel electrophoresis technique. The metal complexes were also screened for their antioxidant, anti‐inflammatory and antibacterial activities and the findings have been reported.

Synthesis, spectral, thermal and biological studies of mixed ligand complexes with newly prepared Schiff base and 1,10-phenanthroline ligands

A series of mixed ligand complexes were prepared from the Schiff base (L1) as a primary ligand, prepared by condensation of oxamide and furan-2-carbaldehyde, and 1,10-phenanthroline (1,10-phen) as a secondary ligand. The Schiff base ligand and its mixed ligand chelates were characterized based on elemental analysis, IR, 1H NMR, thermal analysis, UV–Visible, mass, molar conductance, magnetic moment. X-ray diffraction, solid reflectance and ESR also have been studied. The mixed ligand complexes were found to have the formulae of [M(L1) (1,10-phen)]Clm.nH2O (M = Cr(III) and Fe(III) (m = 3) (n = 0); M = Mn(II), Cu(II) and Cd(II) (m = 2) (n = 0); and M = Co(II) (m = 2) (n = 1), Ni(II) (m = 2) (n = 2) and Zn(II) (m = 2) (n = 3)) and that the geometrical structure of the complexes were octahedral. The parameters of thermodynamic using Coats–Redfern and Horowitz–Metzger equations were calculated. The synthesized Schiff base ligand, 1,10-phenanthroline ligand and Their mixed ligand complexes were also investigated for their antibacterial and antifungal activity against bacterial species (Gram−Ve bacteria: Pseudomonas aeruginosa and Escherichia coli) and (Gram + Ve bacteria: Bacillus subtilis and Streptococcus pneumonia) and fungi (Aspergillus fumigates and Candida albicans). The anticancer activity of the new compounds had been tested against breast (MFC7) and colon (HCT-116) cell lines. The results showed high activity for the synthesized compounds.

Synthesis Characterization and Biological Influence of Some Newly Synthesized Mix ligand Chelates

Objective: A series of mixed ligand chelates of d10 were synthesized expending 3TC a potent nucleoside analogue and ACV, is a guanosine analogue antiviral drug. Methods: The synthesized chelates were characterized by IR, Mass spectra, TGA analysis and Elemental analysis and were evaluated for their anti-fungal activity against a panel of two pathogenic fungal strains namely, Aspergillus niger, and Candida albicans by Broth-dilution method, antibacterial activity against E. coli, P. aeruginosa, S. aureus, S. pyogenus. Results: All the compounds showed significant inhibitory activity against the microorganism. Anti-bacterial activity was determined using Ampicillin as a standard and antifungal activity was determined using standard Greseofulvin. Conclusion: Out of all the chelates, the chelate of Cd2+ exhibited promising antimicrobial activity as a whole.

Oxovanadium(iv) cations in heterometallic and heteroligand complex formation

The formation of heterometallic oxovanadium(iv) diethylenetriaminepentaacetates with titanium(iii), chromium(iii), cobalt(ii), nickel(ii), and manganese(ii) cations in aqueous solutions was studied by spectrophotometry and pH-metry. The stabilizing influence of heterometallic chelation on an unstable oxidation state of Ti iii and the labilizing effect of oxovanadium(iv) cations on the coordination of Cr iii cations by the carboxylate ligand anions in the heterometallic complex were shown. The optimum conditions for the formation of the heterometallic dtpa complexes were selected and their thermodynamic stability was estimated. The states of the oxovanadium(iv) cations in the monoand heteroligand systems involving polyamine, polyaminopolycarboxylate, and alkylpolyphosphonate ligands were studied. Specific features of ligand coordination and formation of the mixed-ligand chelates were investigated. A variety of molecular compositions of complex oxovanadium(iv) oxyethylenediphosphonate particles formed in ranges of pH 2.2—3.0, 4.5—5.5, and 6.3—6.4 was found. The preferability of formation of polynuclear oxovanadium(iv) oxyethylidenediphosphonates, viz., binuclear particles with oxovanadium(iv) cation to ligand molar ratios of 2 : 1 and 2 : 5 and trinuclear particles with a molar ratio of components of 3 : 2, was shown.

Mixed-Ligand Chelate Formation of Co(II), Ni(II), Cu(II) and Zn(II) Ions with Schiff Base as Main Ligand and Amino Acid as Co-Ligand

A bidentate NO type Schiff base ligand (L) has been obtained by the condensation reaction of 4dimethylaminobenzaldehyde and 2-aminophenol and used as main ligand and l-Alanine as coligand (L 2 ), Four novel mixed ligand chelates of composition [M(L 1 L 2 )(H2O)2].nH2O, where M represents, Co(II), Ni(II), Cu(II) and Zn(II) ions, in which n= 1, 1.7, 5 and 7 as sited later for chelates. The resulting Schiff base and the mixed ligand chelates were characterized by CHN elemental analysis, molar conductivity, magnetic moment, UV/Vis, IR, H-NMR and mass spectra. All the obtained physiochemical data showed an octahedral structures. Original Research Article El-ajaily et al.; IRJPAC, 5(3): 229-237, 2015; Article no.IRJPAC.2015.020 230

Modification on Synthesis of Mixed Ligand Chelates by Using Di- and Trivalent Transition Metal Ions with Schiff Base as Primary Ligand

New mixed ligand chelates synthesized from di-and trivalent metal ions (Cr, Co, Ni, and Cu ions) and Schiff base (L1) resulted from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol as primary ligand, whereas 2-nitroaniline (L2) represents the secondary ligand in a molar ratio of M:L1:L2 [1:1:1]. The synthesized Schiff base and chelates have been characterized by using several tools, such as, elemental analysis, molar conductivity, magnetic moment measurements, infrared and electronic spectra. The mass spectra of the ligands and Ni(II) chelate were used to justify the process of modification, as well as, the electron paramagnetic resonance spectrum which was carried out for Cu(II) chelate all in order to elucidate the chemical and geometrical structure of the chelates. On the basis of the obtained data, the geometry of the products was proposed for all the chelates.

Excitation energy transfer in europium chelate with doxycycline in the presence of a second ligand in micellar solutions of nonionic surfactants

The complexation of Eu3+ with doxycycline (DC) antibiotic in the presence of several second ligands and surfactant micelles of different types is studied by the spectrophotometric and luminescence methods. It is found that the efficiency of excitation energy transfer in Eu3+-DC chelate depends on the nature of the second ligand and surfactant micelles. Using thenoyltrifluoroacetone (TTA) as an example, it is shown that the second ligand additionally sensitizes the europium fluorescence, and the possibility of intermediate sensitization of DC and then of europium is shown by the example of 1,10-phenanthroline. In all cases, the excitation energy transfer efficiency was increased due to the so-called antenna effect. The decay kinetics of the sensitized fluorescence of the binary and mixed-ligand chelates in aqueous and micellar solutions of nonionic surfactants is studied and the relative quantum yields and lifetimes of fluorescence are determined.

Novel reagent for synthesis of mixed ligand chelates

Novel reagent for synthesis of mixed ligand chelates

Mixed ligand chelates of copper(II) with substituted diamines

The copper complexes, oxalato( N, N, N′ N′-tetramethylethylenediamine)copper(II) tetrahydrate ( 1), oxalato( N, N, N′-trimethyl-1,3-propanediamine)copper(II) ( 2), and oxalato( N, N, N′-trimethylethylenediamine)copper(II) ( 3), have been synthesized and structurally characterised. Compounds 1 and 2 share a common zig-zag polymeric structure in which the oxalates are bridging as well as chelating. The copper is in a distorted octahedral position in both compounds. Compound 3 is monomeric and the oxalate is chelating only. The copper is in a distorted square planar position. Diffuse reflectance spectroscopy and ESR spectroscopy showed a clear difference between the two types of structures.

Mixed ligand chelates of some multidentate heterocycles with cobalt(II) and nickel(II) imides

Twentyfourmetal chelates of the type [Ni(lm) 2 (B 1 ) 2 ],K[Ni(lm) 2 (B 2 )(H 2 O) 2 ],[Co(lm0 2 (B! 1 )]and K 2 [Co(lm)(B 2 ) 2 ],where Im = deprotonated phthalimideor malonimide,B = 2-aminothiazoleor 2-aminobenzothiazoleand HB 2 =heterocyclic SchilT bases,have been prepared. The metal al is coordinated through nitrogen of deprotontedimide. nitrogen of azomethineand oxygenof deprotonated phenolic hydroxyl group of the Schiff bases.The chelates are of octahedral, tetragonal, tetrahedral and octahedral structures, respectively.

Ruthenium complexes of 2-[(4-(arylamino)phenyl)azo]pyridine formed via regioselective phenyl ring amination of coordinated 2-(phenylazo)pyridine: isolation of products, X-ray structure, and redox and optical properties.

Aromatic ring amination reactions in the ruthenium complex of 2-(phenylazo)pyridine is described. The substitutionally inert cationic brown complex [Ru(pap)(3)](ClO(4))(2) (1) (pap = 2-(phenylazo)pyridine) reacts smoothly with aromatic amines neat and in the presence of air to produce cationic and intense blue complexes [Ru(HL(2))(3)](ClO(4))(2) (2) (HL(2) = 2-[(4-(arylamino)phenyl)azo]pyridine). These were purified on a preparative TLC plate. The X-ray structure of the new and representative complex 2c has been solved to characterize them. The results are compared with those of the starting complex, [Ru(pap)(3)](ClO(4))(2) (1). The transformation 1 --> 2 involves aromatic ring amination at the para carbon (with respect to the diazo function) of the pendant phenyl rings of all three coordinated pap ligands in 1. The transformation is stereoretentive, and the amination reaction is regioselective. The extended ligand HL(2) coordinates as a bidentate ligand and chelates to ruthenium(II) through the pyridine and one of the azo nitrogens. The amine nitrogen of this bears a hydrogen atom and remains uncoordinated. Similarly, the amination reaction on the mixed-ligand complex [Ru(pap)(bpy)(2)](ClO(4))(2) produces the blue complex [Ru(HL(2))(bpy)(2)](ClO(4))(2) (3) as anticipated. The reactions of [RuCl(2)(dmso)(4)] and [Ru(S)(2)(L)(2)](2+) (dmso = dimethyl sulfoxide, S = labile coordinated solvent, L = 2,2'-bipyridine (bpy) and pap) with the preformed HL(2) ligand have been explored. The structure of the representative complex [RuCl(2)(HL(2a))(2)] (5a) is reported. It has the chlorides in trans configuration while the pyridine as well as azo nitrogens are in cis geometry. Optical spectra and redox properties of the newly synthesized complexes are reported. All the ruthenium complexes of HL(2) are characterized by their intense blue solution colors. The lowest energy transitions in these complexes appear near 600 nm, which have been attributed to intraligand charge-transfer transitions. For example, the lowest energy visible range transition in [Ru(HL(2b))(3)](2+) appears at 602 nm and its intensity is 65 510 M(-1) cm(-1). All the tris chelates show multiple-step electron-transfer processes. In [Ru(HL(2))(3)](2+), six reductions waves constitute the complete electron-transfer series. The electrons are believed to be added successively to the three azo functions. In the mixed-ligand chelates [Ru(HL(2))(pap)(2)](2+) and [Ru(HL(2))(bpy)(2)](2+) the reductions due to HL(2), pap, and bpy are observed.

Some Observations on the Spectrophotometry Determination of Di-And Trihydric Phenols by Edta Titration

Novel reaction between trioxalatoferrate (III) complex (A) and some di- and trihydric phenols were studied and found to form interesting mixed ligand chelates of iron (III) in the ratio 1:2:1 (Fe : oxalate : phenol) forming blue to violet colors at pH 4.0 to 6.5 and λmax = 580 to 590 nm. These reactions were used for indirect volumetric and spectrophotometric microdetermination of catechol (PC), pyrogallol (PG), dopamine hydrochloride (DHCl), adrenaline hydrogen tartrate (AHT) and sulbutamol sulfate (SS) via EDTA titration using complex (A) as an indicator. PC, DHC1 and PG were determined by EDTA titration within the concentration ranges of 0.55-2.2, 0.95-3.79 and 0.65-2.52 μg ml−1, respectively. AHT was determined in the concentration range of 96 to 204 μg ml−1 and SS was also determined in the range 5.75 to 57.7 μg ml−1. Adrenaline in ampoules coming from two Egyptian companies: sulbutamol in sulbovent liquids, and dopamine in five urine samples of Egyptian tumor patients, was also determined using the suggested procedure with high accuracy.

ANTIMICROBIAL ACTIVITY OF CADMIUM(II) CHELATES WITH 2, 2′-BIPYRIDYLAMINE AND PHENOLS

The present paper deals with the isolation of mixed ligand chelates of the type CdAL, where A = 2, 2′-bipyridylamine and L = phenols such as catechol (catecholato-2) pyrogallol (pyro-gallolato-3), 2, 3-dihydroxy naphthalene (2, 3-dihydroxy naphthalato-2) or protocatechuic acid (protocatechuato-3). The antimicrobial activity of 2, 2′-bipyridylamine and the CdAL mixed ligand chelates is described.

Preparation and spectral study of mixed-ligand nickel (II) chelates containing N- or N,N′-methylated ethylenediamines and tropolonate or hinokitiolate ligands

Eleven mixed-ligand chelates of Ni (II) containing a molecule of N,N-di-, N,N,N′-tri-, or N,N,N′,N′-tetramethylethylenediamine, and a tropolonate (trop) or hinokitiolate (hino) ligand, were prepared, and their electronic spectra in solid state and in various organic solvents were studied. Most systems studied were green, containing octahedral chelate species [Ni (trop\\hino) (diamine) (H2O\\Solvent) 2] + or [Ni (NO3) (trop\\hino) (diamine) ] , but some were red, containing square planar [Ni (trop\\hino) (diamine) ] +, and an equilibrium between the octahedral and square planar species was sometimes observed in solutions. Strong spectral resemblances with the corresponding diamine-β-diketonate chelates of Ni (II) could be pointed out.