Co(III) N,N′-diarylformamidine dithiocarbamate complexes: Synthesis,characterization, crystal structures and biological studies

Three symmetric N,N-diarylformamidine dithiocarbamates, N,N′-bis(2,6-dimethylphenyl)formamidine dithiocarbamate (DTL1), N,N′-bis(2,6-disopropylphenyl)formamidine dithiocarbamate (DTL2) and N,N′-dimesitylformamidine dithiocarbamate (DTL3), and three unsymmetric ones, N′-(2,6-dichlorophenyl-N-(2,6-dimethylphenyl)formamidine dithiocarbamate (DTL4), N′-(2,6-dichlorophenyl)-N-(2,6-diisopropylphenyl)formamidine dithiocarbamate (DTL5) and N′-(2,6-dichlorophenyl)-N-mesitylformamidine dithiocarbamate (DLT6), were reacted with chloridocobalt(III) in water to give Co-(DTL1)₃ ( 1 ), Co-(DTL2)₃ ( 2 ), Co-(DTL3)₃ ( 3 ), Co-(DTL4)₃ ( 4 ), Co-(DTL5)₃ ( 5 ) and Co-(DTL6)₃ ( 6 ). All the dithiocarbamates and complexes were characterized using ¹H NMR, ¹³C NMR, Fourier transform infrared, UV–visible and mass spectra and the purity confirmed by elemental analysis. In addition, crystal structures of complexes 1 , 2 , 4 and 5 were determined, confirming the formation of mononuclear species in which the Co(III) centers coordinated to six sulfur atoms from three dithiocarbamate ligands resulting in distorted octahedral geometries. All complexes showed moderate to good antibacterial activities against Gram-negative bacteria Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae and Pseudomonas aeruginosa even at low concentrations. None of the six were active against Gram-positive bacterium methicillin-resistant Staphylococcus aureus and only active against S. aureus at high concentrations. Complexes 5 and 6 were found to be more active than ciprofloxacin against S. typhimurium, E. coli, P. aeruginosa and K. pneumoniae and complexes with chloro-substituted ligands generally had enhanced activities. Antioxidant activities of the dithiocarbamate salts and their Co(III) complexes were also investigated using DPPH assay and the complexes were found to be more efficient. Complex 2 with an IC₅₀ value of 2.84 × 10⁻⁴ mM displayed the highest activity of all compounds tested, even outdoing ascorbic acid. The radical scavenging ability of the complexes followed the order 2 > 1 > ascorbic acid > 3 > 4 > 6 > 5 .     

Synthesis,characterization and antimicrobial activity studies of N - N ′-tetracarboxydiethyloxamide ligand and its metal(II) complexes

N-N′-tetracarboxydiethyloxamide (hereafter abbreviated as H₆L) was prepared by using L-aspartic acid and diethyl oxalate (DEO). A series of binuclear complexes of divalent metal chlorides viz. Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with H₆L have been prepared. Spectral studies (IR, UV and NMR) magnetic susceptibility, elemental analysis and molar conductance measurements confirm the formation of binuclear complexes, [M₂H₂L]/[M₂H₂L?·?4H₂O]. Electronic absorption spectra and magnetic susceptibilities suggest square-planar stereochemistry for Cu(II) and tetrahedral for Zn(II) complexes. Mn(II), Co(II), and Ni(II) coordinate two molecules of water and consequently show octahedral geometry. The in vitro antimicrobial activity of the synthesized compounds is discussed against bacterial strains such as S. aureus, S. epididermis, K. pneumonia, S. typhi, P. aerugenosa, and B. subtilis A. brasilense. The metal complexes show higher activity against all the microorganisms than the ligand.     

Polymer complexes,XXIII: Synthesis and physico-chemical studies on transition metal complexes of symmetric novel poly(N,N′-o-phenylenediamine)-bis(cinnamaldehyde)

Summary New complexes derived from polymeric N,N-o-phenylenediamine bis(cinnamaldehyde) (L) with Cu^II, Co^II, Ni^II, Zn^II, UO ₂ ^II , and Pd^II were prepared and characterized by elemental analysis, magnetic susceptibilities and spectroscopic (IR, far-IR,¹H-NMR,¹³C-NMR and EPR) studies. A bidentate methine nitrogen atoms coordination of the ligand is assigned in the isolated complexes. The stereochemistries of the polymer complexes have been studied with using magnetic and spectroscopic measurements. Analytical data show 2:1 or 1:1 (ligand:metal) stoichiometry with water molecules coordinated to the Zn^II ion, as evidenced from IR and thermal analysis (DTA). The ligand was tested as a corrosion inhibitor for copper; the limiting concentration of the ligand to give maximum efficiency (60%) is 10^–3 mol dm^–3 at 25°C.

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Polymere Komplexe, XXIII: Synthese und physikalisch-chemische Untersuchungen an Übergangsmetallkomplexen von symmetrischem Poly(N,N-o-phenylendiamin)bis(zimtaldehyd)

Zusammenfassung Es wurden neue Komplexe von polymerem Poly(N,N-o-phenylendiamin)bis-(zimtaldehyd) mit Cu(II), Co(II), Ni(II), Zn(II), UO₂(II) und Pd(II) hergestellt und mittels Elementaranalyse, magnetischen Suszeptibilitätsmessungen und spektroskopischen Methoden (IR, far-IR,¹H-NMR,¹³C-NMR und EPR) charakterisiert. Es wurde eine zweizähnige Methin-Stickstoff-Koordination in den Komplexen festgestellt. Die Stereochemie der Polymerkomplexe wurde mittels magnetischer und spektroskopischer Messungen untersucht. Aus den analytischen Daten, mit zusätzlichen Argumenten aus IR und thermischer Analyse (DTA), ergab sich eine 2:1 oder 1:1 (Ligand:Metall)-Stöchiometrie mit an Zn(II) koordinierten Wassermolekülen. Der Ligand wurde als Korrosionsinhibitor für Kupfer getestet: die Grenzkonzentration des Liganden zur maximalen Effizienz (60%) ist 10^–3 mol dm^–1 bei 25°C.

     

Thermochemistry of Cu(II) and Ni(II) complexes with N,N-di-n-butyl-N′-thenoylthiourea and N,N-di-iso-butyl-N′-thenoylthiourea

Two substituted N-acylthioureas and the respective Ni(II) and Cu(II) complexes were synthesized, namely: N,N-di-n-butyl-N′-thenoylthiourea (Hnbtu); N,N-di-iso-butyl-N′-thenoylthiourea (Hibtu); bis[N,N-di-n-butyl-N′-thenoylthioureato]nickel(II), [Ni(nbtu)₂]; bis[N,N-di-n-butyl-N′-thenoylthioureato]copper(II), [Cu(nbtu)₂]; bis[N,N-di-iso-butyl-N′-thenoylthioureato]nickel(II), [Ni(ibtu)₂]; bis[N,N-di-iso-butyl-N′-thenoylthioureato]copper(II), [Cu(ibtu)₂]. The standard (p^° = 0.1 MPa) molar enthalpies of formation and sublimation of the two N-acylthioureas were measured, at T = 298.15 K, by rotating-bomb combustion calorimetry and Calvet microcalorimetry, respectively. The standard (p^° = 0.1 MPa) molar enthalpies of formation of the Ni(II) and Cu(II) complexes were determined, at T = 298.15 K, by high precision solution–reaction calorimetry. From the results obtained, the enthalpies of hypothetical metal–ligand and metal–metal exchange reactions, in the gaseous phase, were derived, thus allowing a discussion of the gaseous phase energetic difference between the complexation of Ni(II) and Cu(II) to 1,3-ligand systems with (S,O) ligator atoms.     

Mononuclear copper(I) complexes with triphenylphosphine and N,N′-disubstituted thioureas: synthesis,characterization, and biological evaluation

Abstract

Twelve new complexes, of the general formula CuCl(TPP)₂Tu^1–12 (Tu?=?thiourea), were synthesized by the reaction of CuCl(TPP)₃ (TPP?=?triphenylphosphine) and various N,N′-disubstituted thioureas. The structures of the synthesized complexes were characterized by different techniques such as Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy (¹H, ¹³C, ³¹P, and ¹⁹F), and the representative complexes (1, 2 and 12) were analyzed via single crystal X-ray diffraction. The single crystal X-ray analysis revealed that copper(I) is coordinated with chlorine, two TPP, and the thiourea ligands through the sulfur atom in a mononuclear distorted tetrahedral mode. The compounds were tested for antibacterial, antifungal, cytotoxicity, antileishmanial, and antioxidant activities. The results showed that the synthesized complexes are significantly more active than the free ligands and the commercial reference compounds. The high biological activities of the complexes versus free ligands can be attributed to the copper(I) chloride complexation with thiourea ligands. The synthesized complexes were also evaluated, both experimentally and theoretically, for DNA binding studies. The UV-visible spectroscopic and molecular docking studies demonstrated that the complexes are conjugating with DNA through a groove binding mode.     

Synthesis and structural characterization of heteroleptic Cu(I) complexes with α-diimines derived from pyridinyliminobenzoic acids

The synthesis and molecular and electronic structure of heteroleptic univalent copper compounds [Cu(L)(PPh₃)X] are reported where X is a halide and L represents 3-pyridinylimino, 4-pyridinylimino or 3,5-dipyridinylimino-substituted benzoic acid, hereafter abbreviated as L1, L2, and L3, respectively. The crystal structures of two iodide and one bromide complexes are described. All compounds are hydrogen-bonded dimers. The electronic excitation spectra of the compounds are dominated by intraligand bands of ligands while characteristic MLCT transitions are observed at 430–480?nm. No emission is observed from the compounds either in the solid state or in solution; on the contrary a photodecomposition is observed resulting in triphenylphosphane ligand elimination and formation of halogen-bridged dimmers.     

Synthesis,characterization and biological studies on unsymmetrical Schiff-base complexes of nickel(II), copper(II) and zinc(II) and adducts with 2,2′-dipyridine and 1,10-phenanthroline

A series of metal(II) unsymmetrical Schiff-base complexes, {M(C₁₀H₆OCH:N(CH₂)₂N?:?C(CH₃)CH?:?C(CH₃)O), where M=Ni(II), Cu(II) and Zn(II)}, and their 2,2′-dipyridine (bipy) and 1,10-phenanthroline (phen) adducts are synthesized and characterized by microanalysis, magnetic susceptibility, conductance, IR and UV-Vis spectra. The ligand coordinates using the N₂O₂ chromophore to give a two-metal-center four-coordinate square-planar geometry. IR and UV-Vis spectra are consistent with octahedral adducts. The compounds are non-electrolytes in nitromethane and magnetic moments indicate that the complexes are magnetically dilute. The antimicrobial activity of the compounds against ten bacteria and one fungus are reported. The Cu(II) and Zn(II) complexes showed good activity against many of the organisms while their adducts are generally not sensitive. The minimum inhibitory concentrations (MICs) of the sensitive compounds are between 3.0–13.0?mg?mL^?1.     

Synthesis,characterization, and biological evaluation of silver(I) complexes of N′-(1-(pyrazin-2-yl)ethylidene)picolinohydrazide

Three Ag⁺ complexes, [Ag(L)(NO₃)]_n (1), {[Ag(L)]·SbF₆·CH₂Cl₂}_n (2), and {[Ag(L)]·SO₃CF₃·CHCl₃}_n (3), based on a hydrazone ligand L have been obtained (L = N′-(1-(pyrazin-2-yl)ethylidene)picolinohydrazide) and characterized. Complexes 1–3 all show 1-D chain-like structures. Their antibacterial activity and interaction with serum albumin were investigated. These results indicate that these complexes show good antibacterial activities and binding affinity to serum albumin.     

Synthesis,characterization and anti-microbial activity of poly(ethylene oxamide- N,N ′-disuccinate) and its polymer metal complexes

Poly(ethylene oxamide-N,N′-disuccinate), abbreviated as (PEODS), has been synthesized by condensation of oxamide-N,N′-disuccinic acid and 1,2-ethylene glycol. Coordination polymers were synthesized by the reaction of (PEODS) with hydrated acetates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The resulting polyester-metal complexes were characterized by elemental analysis, UV-Visible, FT-IR, ¹H-NMR, ESR spectroscopy and magnetic susceptibilities. Thermal behavior of all the synthesized compounds revealed that polymer metal complexes are more stable than the polymeric ligand. In addition all the synthesized polymers were screened for anti-bacterial activity against B. subtelillisr, B. megaterium, S. aureus, E. coli, S. typhi, P.?aeruginosa, S. boydii and for antifungal activity against C. albicans, T. species, A. flavus, A. niger, F. species, M. species, and P. species by agar well diffusion methods. All the polymers showed good anti-bacterial and anti-fungal activity, which increased on coordination with the metal ions.     

New σ-alkynylides of Cu(I) and Ag(I)

Polymeric compounds of the type (MCCR)_x (MCu, Ag; R = cyclohexyl, n-hexyl) and M₂(p-(CC)C₆H₄)] _x (MCu, Ag) have been prepared. The preparation media and solvent (liquid ammonia, methanol and methanol/ or methanol-ether/aqueous ammonia) exert an influence over the nature of the alkynyl compound, leading either to the formation of adducts or to the formation of metal alkynylides with identical empirical formulae, but differing in colour, which seems be related to the different extent of molecular association.     

N′N′N pincer and N′N bidentate(pyrazolylpyridyl) Rh(I) complexes as catalyst precursors for hydroformylation of olefins

Transition Metal Chemistry - The industrial process of hydroformylation or the oxo process has been used for many years in the production of aldehydes from alkenes. Different metals have been used...     

Preparation and molecular structures of N,N-2,2′-dipicolyl- and N,N-3,3′-dipicolyldithiocarbamato metal complexes

New iron(III) and cobalt(III) complexes, [Fe(2,2′-dpdtc)₃], [Fe(3,3′-dpdtc)₃], [Co(2,2′-dpdtc)₃], and [Co(3,3′-dpdtc)₃] (dpdtc?=?dipicolyldithiocarbamate) have been synthesized and their molecular structures and spectroscopic properties determined. The 2,2′- and 3,3′-dpdtc ligands have four donors, S, S′, N, and N′. These complexes are insoluble in water, but soluble in acidic solution. Crystal structures of these metal complexes reveal that the central metal ions have MS₆ (M?=?Fe and Co) octahedral structures and all dipicolyl groups do not coordinate.     

Synthesis,characterization and antimicrobial activities of transition metal complexes of N,N -dialkyl- N′ -(2-chlorobenzoyl)thiourea derivatives

N,N-di-n-propyl-N′-(2-chlorobenzoyl)thiourea (HL¹) (1), N,N-diphenyl-N′-(2-chlorobenzoyl)thiourea (HL²) (2), and their Ni^II, Co^II, Cu^II, Zn^II, Pt^II, Cd^II and Pd^II complexes have been synthesized and characterized. HL¹ and its copper complex were characterized by single-crystal X-ray diffraction methods. The ligands coordinate as bidentates yielding essentially neutral complexes of the type [ML₂]. The complexes were screened for their in vitro antibacterial, antifungal activities and toxicity. All compounds showed antimicrobial activity, but antibacterial efficacy is greater than antifungal activity.     

Synthetic,magnetic, spectral,antimicrobial and antifertility studies of dioxomolybdenum(VI) unsymmetrical imine complexes having a N ∩ N donor system

Unsymmetrical imine molybdenum(VI) complexes of the type [MoO₂(L¹)(L²)] formed by the interaction of dioxobis(2,4-pentanedionato)molybdenum(VI) in a 1:1:1 molar ratio with different imines derived from the reactions of sulphagunanidine, sulphamethazine, sulphapyridine and sulphadiazine with various aromatic aldehydes and ketones, have been prepared and the products characterized by elemental analysis, molar conductance, magnetic measurements and spectral studies. The complexes have also been tested in vitro. The antifertility screening data indicate the antiandrogenic nature of the complexes. The spectral studies suggest that all the ligands behave in a bidentate fashion, coordinating through the azomethine nitrogen (>C=N–) and other functional group NH as (N N) donors. Studies also reveal that the ligands react with dioxobis(2,4-pentanedionato)molybdenum(VI) to give diamagnetic mononuclear molybdenum(VI) complexes.     

Copper (I) and silver (I) complexes of dithiomalonamide,NN′-dimethyl- and NN′-diphenyl-dithiomalonamide.

Some copper (I) and silver (I) complexes with dithiomalonamide (Hdtma), NN′-dimethyl-(HMe₂dtma) and NN′-diphenyl-dithiomalonamide (HPh₂dtma) were prepared: Cu(Hdtma)X (X² = Cl, Br, I(H₂O), ClO₄); Cu(HL)₂X (HMe₂dtma: X = Cl, Br, I, ClO₄; HPh₂dtma: X = Cl, Br, I); Ag(HL)X (Hdtma: X = Cl; HMe₂dtma: X = Br, ClO₄, BF₄; HPh₂dtma: X = Br, I); Ag₂(HL)₃X₂ (Hdtma: X = ClO₄, BF₄; HMe₂dtma: X = Cl; HPh₂-dtma: X = Cl, ClO₄); Ag₂(HMe₂dtma)I₂ and Ag₃(Hdtma)₂Br₃. Molar conductivities in DMF show that the complexes behave: M₂(HL)₃(ClO₄)₂ as 1:2 electrolytes, M(HL) (ClO₄ of BF₄) as 1:1 electrolytes; those of the halides Cu(HL)X and Cu(HL)₂X, are almost equal and intermediate between values for non-electrolytes and 1:1 electrolites. Infrared spectra indicate an S,N-coordination for all the complexes: ν(MN) bands in the region of 400–500 cm⁻¹ and ν(MS) bands in the region of 300–400 cm⁻¹ (for Hdtma), 300–320 cm⁻¹ (for HMe₂dtma) and 260–280 cm⁻¹ (for HPh₂dtma) are observed. No ν(MX) bands were identified in the halide complexes indicating that a mental—halide coordination, if present in the solid complexes, should be very weak.     

Synthesis,characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

A new series of copper(II) mononuclear and copper(II)–metal(II) binuclear complexes [(H₂L)Cu] ? H₂O, [CuLM] ? nH₂O, and [Cu(H₂L)M(OAc)₂] ? nH₂O, n = 1–2, M = Co(II), Ni(II), Cu(II), or Zn(II), and L is the anion of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone), H₄L, were synthesized and characterized. Elemental analyses, molar conductivities, and FT-IR spectra support the formulation of these complexes. IR data suggest that H₄L is dibasic tetradentate in [(H₂L)Cu] ? H₂O and [Cu(H₂L)M(OAc)₂] ? nH₂O but tetrabasic hexadentate in [CuLM] ? nH₂O (n = 1–2). Thermal studies indicate that waters are of crystallization and the complexes are thermally stable to 347–402°C depending upon the nature of the complex. Magnetic moment values indicate magnetic exchange interaction between Cu(II) and M(II) centers in binuclear complexes. The electronic spectral data show that d–d transitions of CuN₂O₂ in the mononuclear complex are blue shifted in binuclear complexes in the sequences: Cu–Cu > Cu–Ni > Cu–Co > Cu–Zn, suggesting that the binuclear complexes [CuLM] ? nH₂O are more planar than the mononuclear complex. The structures of complexes were optimized through molecular mechanics applying MM ⁺force field coupled with molecular dynamics simulation. [(H₂L)Cu] ? nH₂O, [CuLM] ? nH₂O, and the free ligand were screened for antimicrobial activities on some Gram-positive and Gram-negative bacterial species. The free ligand is inactive against all studied bacteria. The screening data showed that [CuLCu] ? H₂O > [(H₂L)Cu] ? H₂O > [CuLZn] ? H₂O > [CuLNi] ? 2H₂O ≈ [CuLCo] ? H₂O in order of biological activity. The data are discussed in terms of their compositions and structures.     

Theoretical predictions of the nitrogen heterocyclic compounds with metal and noble gas (metal = Cu,Ag, Au)

Here, we report a new type of Ng-containing compounds formed between the Ng-M group and nitrogen heterocyclic compounds, (CH₂)_nHNCuNg⁺ (n = 2, 3), (CH)₄NMNg, and (CH)₅NCuNg⁺ (M = Cu, Ag, Au; Ng = Ar, Kr, Xe). Quantum chemistry computations were carried out to optimize their geometric structures and calculate the dissociation energies, dissociation enthalpy, and dissociation free energy change. The stability of these Ng-bonding complexes was inspected by investigating the three dissociation processes of the these compounds into (a) Ng, M, and nitrogen heterocycle C_nN; (b) C_nN + MNg⁺; and (c) C_nNM + Ng, which are all endothermic and nonspontaneous, these dissociation processes are also turned out to be endergonic in nature at standard state. The natural bond orbital, atoms in molecules, and energy decomposition analysis based on the molecular wavefunction show that the M-Ng and M-N bonds have some covalent and electrostatic characters.