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.     

Studies on platinum(II) and palladium(II) complexes of some N,N′-disubstituted thiourea derivatives

Summary A series of new Pt^II and Pd^II complexes of N,N-disubstituted thiourea derivatives of general formulae [MLCl₂]₂, [ML₂Cl₂] and [ML₄]Cl₂ have been prepared and characterised by physicochemical and spectroscopic methods. The reaction of these ligands with [M(DMSO)₂Cl₂], M = Pt, cis- or Pd, trans-, in CHCl₃ and EtOH at ambient temperature or under reflux, is described.     

A calorimetric study of N,N-diethyl-N′-furoylthiourea and N,N-diisobutyl-N′-furoylthiourea

The standard ( p^o =  0.1 MPa) molar enthalpies of combustion in oxygen, at T =  298.15 K, were measured by rotative bomb calorimetry for crystalline N, N -diethyl- N^′-furoylthiourea, (2-C₄H₃O)CONHCSN(C₂H₅)₂, HFET, and N, N -diisobutyl- N^′-furoylthiourea, (2-C₄H₃O)CONHCSN(iso-C₄H₉)₂, HFIB. The standard molar enthalpies of sublimation of both HFET and HFIB were measured by high-temperature Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds, in their crystalline and gaseous phases.     

Some group VB chloride complexes with thiourea and N,N′-diethyl-dithiooxamide

The following complexes of thiourea(tu) and N,N′-diethyl-dithioxamide (Et₂DH₂) with phosphorous (III), arsenic(III), antimony(III) and bismuth(III) have been prepared and characterises: PCl₃(tu) (DMF)₂; AsCl₃(tu)₃(DMSO)₃: MCl₃(tu)₃ (M = As, Bi); SbCl₃(tu)₂(DMF) and SbCl₃(Et₂DH₂)_1.5 (C₂H₄Cl₂). IR and NMR (¹H, ¹³C and ³¹P) spectral data provides evidence for ligand attachment exclusively by sulphur coordination in all complexes excepting PCl₃(tu) (DMF)₂. For the latter additional metal-nitrogen bonding is proposed.     

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.     

Thermal and FTIR spectral studies of N,N′-diphenylguanidine

Thermal decomposition of N,N??-diphenylguanidine (DPG) was investigated by simultaneous TG/DSC-FTIR techniques under nonisothermal conditions. Online FTIR measurements illustrate that aniline is a major product of DPG decomposition. The observation that the activation energy depends on the extent of conversion indicates that the DPG decomposition kinetics features multiple processes. The initial elimination of aniline from DPG involves two pathways because of the isomerization of DPG. Mass spectrometry and thin film chromatography suggest that there are two major intermediate products with the major one of C₂₁N₃H₁₇. The most probable kinetic model deduced through multivariate nonlinear regression method agrees well with the experimental data with a correlation coefficient of 0.9998. The temperature-independent function of conversion f(??), activation energy E and the pre-exponential factor A of DPG decomposition was also established through model-fitting method in this research.     

The characterization of some square planar Ni(II) complexes of N,N′-ethylenebis (isonitrosoacetylacetoneimine)

The ligand (H₂L) is prepared by the condensation of 2 molecules of isonitrosoacetylacetone with 1 molecule of ethylenediamine. The dimeric nature of the ligand is compatible with the types of the square planar Ni(II) complexes it produces with NiX₂(X  Cl, NO₃, CH₃CO₂). The 1:1 up to 5:1 molar ratio reaction of nickel chloride with the ligand produced the same complex H₂LNiCl₂ · HLNiCI(I) which did not react with pyridine, while the 1:2 and 1:3 molar ratio reaction afforded the complexes LNi · HLNiCl(II) and (LNi)₂(III) respectively. The reaction of nickel nitrate with (H₂L)₂ led to the formation of the complex LNi · HLNiNO₃(IV). The Ni(II) complex LNi(V) of the monomeric ligand was obtained by either the reaction of nickel acetate with (H₂L)₂ (1:1 or 5:1) or by reacting nickel chloride with the neutral solution of the ligand (1:1 or 2:1). The two anions of the ligand are linked together through either (a) hydrogen bonding formation that involves the oxime groups (H₂L and complex I), (b) coordination of one on the oximato group of a ligand's anion with the chelated metal ion to another ligand's anion (complex III), or (c) by both types of linkages (complexes II and IV). The suggested molecular formulations are based on analytical, spectral and magnetic moment evidence.     

Synthesis, spectral and thermal studies of N,N − -pyridine-2,6-diyl bis[N −-phenyl(thiourea)] and its metal complexes

Four new metal complexes with the general formula, [ML·mH₂O]nH₂O (where, M = Cu(I), Co(II), Ni(II) or Zn(II); L = N,N ^?-pyridine–2,6-diyl bis[N ^?-phenyl (thiourea)] (PDPT); m = 1 or 3 and n = 0.5 or 4.0), have been synthesized and characterized by elemental analyses, spectral analyses (IR, UV–Vis., ¹H-NMR and MS), thermal analyses (TGA), conductivity and magnetic measurements. The results showed that the ligand (PDPT) acts in a mononegative tridentate manner towards Cu(I) ion coordinating via the two thiol sulfurs and pyridyl nitrogen groups with displacement of only one hydrogen atom from the thiol group, while the ligand behaves in a binegative tridentate manner towards the Co(II), Ni(II) and Zn(II) ions with displacement of two hydrogen atoms from the two thiol groups. The value of magnetic measurements showed a diamagnetic character of the copper complex indicating the reduction of Cu(II) to Cu(I). Semi-empirical calculations of the ligand and its metal complexes have been used to study the molecular geometry using ZINDO/1, PM3 and AM1. Also, the harmonic vibration spectra of the ligand and its metal complexes have been investigated with the purpose to assist the experimental assignment of metal complexes. The results of the optical absorption studies reveal that the optical transition is direct with band gaps energy (E_g) values 2.62, 1.98 and 1.85 eV for Cu, Co and Ni complexes, respectively, indicating that these complexes can behave as semi-conductors.     

Production and thermal decomposition of polycondensates containing N,N′-disubstituted thiourea derivatives

Polycondensates containing N,N-ethylenethiourea or N,N-diisopropylthiourea units and titanium or silicon-derived coupling agent molecules were prepared. Their structures were confirmed through FTIR spectroscopy. The thermal decomposition of these polycondensates was studied by means of TG and DTA methods and FTIR and ESR spectroscopy.

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Zusammenfassung Es wurden Polykondensate mit einem Gehalt an N,N-Ethylenthiokarbamidoder N,N-Diisopropylthiokarbamideinheiten und mit Titan oder Silizium abgeleiteten Koppelreagenzmolekülen hergestellt. Ihre Struktur wurde mittels FTIR Spektroskopie bestätigt. Die thermische Zersetzung dieser Polykondensate wurde mittels TG und DTA Verfahren sowie mit Hilfe von FTIR und ESR Spektroskopie untersucht.

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The author thanks Professor P. I. Premovic for valuable discussions. This reseach was supported by the Research Fund of Macedonia, contract 10/1.     

Coordination behaviour and thermolysis of some rare-earth complexes with 4,4′-bipyridine and di- or trichloroacetates

A novel mixed-ligand complexes with empirical formulae: Dy(4-bpy)(CCl₂HCOO)₃ · H₂O and Ln(4-bpy)_1.5(CCl₃COO)₃ · 2H₂O (where Ln(III) = Ce, Nd) were prepared and characterized by chemical and elemental analysis and IR spectroscopy, conductivity (in methanol, dimethyloformamide and dimethylsulfoxide). Analysis of the diffractograms showed that the obtained complexes are crystalline. Way of metal-ligand coordination discussed. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via intermediate products to the oxides: Ln₂O₃ (Nd, Dy) and CeO₂. TG-MS system was used to analyse principal volatile thermal decomposition and fragmentation products evolved during pyrolysis of Dy(4-bpy)(CCl₂HCOO)₃ · H₂O in air.     

N-picolinamido-N′-benzoylthiocarbamide transition metal complexes

A new series of CoII, NiII and CuII complexes derived from N-picolinamido-N-benzoylthiocarbamide has been prepared in which the Schiff base ligand is tridentate and/or bidentate, containing a potential ONS donor. The complexes have been characterized by elemental analyses, 1H-n.m.r., magnetic susceptibility, i.r., u.v., e.p.r. and thermal analyses. Stereochemistries are proposed for the complexes on the basis of the spectral and magnetic studies. The i.r. data indicate that the carbonyl oxygen of the benzoyl moiety constituents chelating backbone in most complexes.     

Dipole moments of some metal complexes of five new monothio-β-diketones

Dipole moments have been determined for Co(III), Ni(II), Pd(II), Pt(II), Cu(II) and Zn(II) complexes of the fluorinated monothio-β-diketones RC(SH)CHCOCF₃ [R  5′-methyl-2′-thienyl, 5′-chloro-2′-thienyl, 4′-isopropylphenyl, 4′-tert-butylphenyl and 3′-fluoro-4′-methoxyphenyl] from static-polarization measurements. The moments clearly indicate cis-square-planar configurations for the nickel, palladium and platinum complexes. The zinc complexes have tetrahedral structure and copper complexes have distorted cis-square-planar structure. The cobalt complexes perhaps have facial-octahedral structure. The values of dipole moment for the complexes varies with R: 5′-methyl-2′-thienyl > 3′-fluoro-4′-methoxyphenyl > 4′-isopropylphenyl ≈ 4′-tert-butylphenyl > 5′-chloro-2′-thienyl.     

Diaza-crown ethers—V: Stability constants of N,N′-disubstituted diaza-crown ether complexes with various metal ions

Stability constants have been determined at 25°C in an aqueous 0.500 M Li(ClO₄) medium by potentiometric methods using the following ligands and metal ions 1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (2,2), N,N′-bis-(2-methoxyethyl)-2,2(BME-2,2), N,N′-bis-(2-hydroxyethyl)-2,2(BHE-2,2), N,N′-bis-(carbamoylmethyl)- 2,2(BCAM-2,2) and Na⁺, K⁺, Mg²⁺, Ca²⁺, Cu²⁺, Ag⁺, Cd²⁺, Pb²⁺, respectively. The magnitude of the stability constants are discussed in terms of metal ion hydration, metal ion/cavity size, hardness/softness of the various acceptors, the type of donor atom and the topology of the ligand. Comparisons are made with other cyclic and bicyclic diazapolyethers.     

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.     

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.     

Binuclear complexes of chromium,manganese and rhodium withN-hydroxyethyl-N,N′,N′-tribenzimidazolylmethylethylenediamine

Summary Three novel binuclear complexes, Cr₂Cl₆L·EtOH, Mn₂OAc₄L·EtOH, Rh₂Cl₆L.2H₂O, where L =N-hydroxyethyl-N,N,N-tribenzimidazolylmethylethylenediamine, have been prepared and characterized by elemental analyses, i.r., u.v.-vis. and e.s.r. spectra, and by magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction exists between the metal ions in a binuclear unit for the dimanganese complex. Preliminary bioassays show that the manganese complex possesses antitumour activityin vitro.     

Thermal decomposition of several N,N′-bis(2-hydroxyiminoalkyl)-α,α′-dinitrones

Journal of Thermal Analysis and Calorimetry - N,N′-Bis(2-hydroxyiminoalkyl)-α,α′-dinitrones are of interest for the synthesis of 1,1′-dihydroxy-2,2′-biimidazoles....     

Reactions of transition metal σ-acetylide complexes: IX. Preparation and properties of some cycloheptatrienylvinylidene complexes

Addition of [C₇H₇][PF₆] to iron, ruthenium or osmium alkynyl complexes has given eight cationic cycloheptatrienylvinylidene derivatives [M{C C(C₇H₇)R}(L)₂ (η-C₅H₅)][PF₆] (M = Fe, Ru or Os; R = Me, Pr, Ph or C₆F₅; L = PPh₃, L₂ = dppm or dppe; but not all combinations). With Fe(C₂Ph)(CO)₂(η-C₅H₅), only [Fe(CO)₂(thf)(η-C₅H₅)][PF₆] was obtained. Reactions of the new complexes are characterised by loss of the C₇H₇ group. The NMR spectra and FAB mass spectra are described in detail.