Synthesis and characterization of bis(nicotinamide) m-hydroxybenzoate complexes of Co(II), Ni(II), Cu(II), and Zn(II)

Mixed-ligand m-hydroxybenzoate complexes of Co(II), Ni(II), Cu(II), and Zn(II) with nicotinamide were synthesized and characterized by elemental analysis, FT-IR spectrometry, solid state UV-vis spectrometry, and magnetic susceptibility measurements. The thermal behavior of the complexes was studied by simultaneous TG-DTA methods in static air atmosphere. The infrared spectral characteristics of the complexes are discussed and the mass spectra data are recorded. The complexes contain two water molecules, two m-hydroxybenzoato (m-hba), and two nicotinamide (na) ligands per formula unit. In these complexes, the m-hydroxybenzoate and nicotinamide behave as a monodentate ligand through acidic oxygen and nitrogen of the pyridine ring. The decomposition pathways and the stability of the complexes are interpreted in terms of the structural data. The final decomposition products were found to be the respective metal oxides. The text was submitted by the author in English.     

Synthesis and characterization of <Emphasis Type="Italic">bis</Emphasis>(nicotinamide) <Emphasis Type="Italic">m</Emphasis>-hydroxybenzoate complexes of Co(II), Ni(II), Cu(II) and Zn(II)

The mixed-ligand m-hydroxybenzoate complexes of Co(II), Ni(II), Cu(II) and Zn(II) with nicotinamide were synthesized and characterized. The chemical, FT IR and UV-vis spectrophotometric, thermal and mass spectral analyses, magnetic susceptibility measurements revealed that the compounds contain two water molecules, two m-hydroxybenzoate (m-hba) and two nicotinamide (na) ligands per formula unit. m-Hydroxybenzoate and nicotinamide ligands bind to the metal atoms monodentately through their acidic oxygen and pyridinic nitrogen atoms, respectively. The thermal decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data.     

Synthesis and characterization of bis(N,N-diethylnicotinamide) <Emphasis Type="Italic">m</Emphasis>-hydroxybenzoate complexes of Co(II), Ni(H), Cu(II), and Zn(II)

Four novel mixed-ligand complexes of Co(II), Ni(II), Cu(II), and Zn(II) with m-hydroxybenzoate (m-Hba) and N,N-diethylnicotinamide (Dena) were synthesized and characterized on the basis of elemental analysis, FT-IR spectroscopic study, and solid state UV-Vis spectrophotometric and magnetic-susceptibility data. The thermal behavior of the complexes was studied by combined TG-DTA methods in static air atmosphere, and the mass spectra were recorded. The Co(II), Ni(II), and Zn(II) complexes, except for the Cu(II) complex, contain two molecules of coordinated water, two m-Hba, and two Dena ligands per formula unit. In these complexes, the m-Hba and Dena behave as monodentate ligands via acidic oxygen and nitrogen of the pyridine ring. In the Cu(II) complex, the m-Hba is coordinated as monoanionic bidentate ligand through acidic oxygen and carbonyl oxygen. Dena is bonded with Cu²⁺ as monodentate ligand by the nitrogen atom of the pyridine ring. The decomposition pathways and the stability of the complexes are interpreted in terms of the proposed structural data. The final decomposition products were found to be the respective metal oxides. The article was submitted by the authors in English.     

Synthesis, structural, spectroscopic characterization, and structural comparison of 3-hydroxybenzoate and nicotinamide/N,N-diethylnicotinamide mixed ligand complexes with Zn(II)

The mixed-ligand 3-hydroxybenzoic acid complex of Zn(II) with nicotinamide and N,N-diethylnicotinamide were synthesized and characterized (colorless single crystals, [Zn(3-hba)₂(H₂O)₂(na)₂] and [Zn(3-hba)₂(H₂O)₂(dena)₂]). The chemical, FT-IR, thermal, mass spectral analyses, and X-ray data results revealed that both of the compounds contain two water molecules, two 3-hydroxybenzoate (3-hba) and two nicotinamide (na) or two N,N-diethylnicotinamide (dena) ligands per formula unit. 3-hba and na or dena ligands bind to the Zn(II) ion monodentately through their acidic oxygen and pyridinic nitrogen atoms, respectively. The coordination of metal atoms are completed by two molecules of aqua ligands. The charge balance of complexes is accommodated by two molecules of 3-hba ions. The unit cell has two molecules coordination molecules and each of them was as settled to four surfaces of unit cell cage in na complex. There is one mole molecule that was occupied to center of unit cell cage in dena complex. The two dimensional network structure of the complex is like a hexagonal for na and square plane for dena complexes. The thermal decomposition takes place in three steps; first, dehydration of the two aqua ligands, second, elimination of the two nicotinamide ligands, finally, burning of the two benzoate ion ligands.     

Synthesis and spectroscopic studies of novel Cu(II), Co(II), Ni(II) and Zn(II) mixed ligand complexes with saccharin and nicotinamide

Four novel mixed ligand complexes of Cu(II), Co(II), Ni(II) and Zn(II) with saccharin and nicotinamide were synthesised and characterised on the basis of elemental analysis, FT-IR spectroscopic study, UV–Vis spectrometric and magnetic susceptibility data. The structure of the Cu (II) complex is completely different from those of the Co(II), Ni(II) and Zn(II) complexes. From the frequencies of the saccharinato CO and SO₂ modes, it has been proven that the saccharinato ligands in the structure of the Cu complex are coordinated to the metal ion ([Cu(NA)₂(Sac)₂(H₂O)], where NA — nicotinamide, Sac — saccharinato ligand or ion), whilst in the Co(II), Ni(II) and Zn(II) complexes are uncoordinated and exist as ions ([M(NA)₂(H₂O)₄](Sac)₂).     

Spectral,thermal and magnetic investigations of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates were investigated and their composition, solubility in water at 295 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with molar ratio of metal to organic ligand of 1.0:1.0 and general formula: M [ CH₃C₆H₃(CO₂)₂]·nH₂o (n=1-3) were recorded and their decomposition in air were studied. During heating the hydrated complexes are dehydrated in one (Mn, Co, Ni, Zn, Cd) or two steps (Cu) and next the anhydrous complexes decompose to oxides directly (Cu, Zn), with intermediate formation of carbonates (Mn, Cd), oxocarbonates (Ni) or carbonate and free metal (Co). The carboxylate groups in the complexes studied are mono- and bidentate (Co, Ni), bidentate chelating and bridging (Zn) or bidentate chelating (Mn, Cu, Cd). The magnetic moments for paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II) attain values 5.92, 5.05, 3.36 and 1.96 M.B., respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Novel coordination compounds: Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) cations with acesulfame/N,N-diethylnicotinamide ligands

Abstract

Five coordination complexes with Mn²⁺ (1), Co²⁺ (2), Ni²⁺ (3), Cu²⁺ (4), and Zn²⁺ (5) containing acesulfame (ace) and N,N-diethylnicotinamide (dena) ligands were synthesized and structural binding properties investigated. Four compounds (1, 2, 4, and 5) were examined with single crystal X-ray diffraction methods. The structures containing Mn(II), Co(II), and Zn(II) were iso-structural. Six-coordination of metal cations were completed with two moles dena and four aqua ligands. The dena ligands were coordinated via pyridine nitrogen as neutral-monodentate. Charge stabilities of the complexes are complemented by two moles monoanionic ace ligands, located outside of the coordination unit. In the Cu(II) complex, the coordination is completed by acidic nitrogen and carbonyl oxygen atoms of two ace ligands and pyridine nitrogen of two moles dena ligands. The coordination to Cu(II) for ace ligands was monoanionic-bidentate. All metal cations in the structure are distorted octahedral. Thermal decomposition of complexes begins with removal of the aqua molecules from the structures and is completed by combustion of organic ligands. The final decomposition products of all structures have been identified as corresponding metal oxides. Some biological applications (anti-fungal/anti-bacterial) were studied using 1–5.     

Infrared spectra of bis(aniline) and bis (p-toluidine) metal(II) isothiocyanate complexes

The infrared spectra of eight complexes of general formula [ML₂(NCS)₂] (M = Co, Ni, Cu, Zn; L = aniline or p-toluidine) have been determined over the range 4000–4150 cm^?1. Colour, magnetic moments and IR spectra are consistent with polymeric octahedral coordination in the Co(II) and Ni(II) complexes and polymeric tetragonal coordination in the Cu(II) complexes, while the Zn(II) complexes are assigned polymeric octahedral (L = aniline) and tetrahedral (L = p-toluidine) structure on the basis of their IR spectra. Independent ¹⁵N-labelling of the nitrogen atoms of the amino and isothiocyanate groups yields assignments for the internal vibrations of both groups and enables the metal-amine and metal—isothiocyanate stretching vibrations (vM-NH₂ and vM-NCS) to be distinguished. Both vM-NH₂ and vM-NCS are metal ion dependent in the Irving-Williams sequence (Co < Ni < Cu > Zn) expected from their proposed structures while the vN-H and vN-CS vibrations are inversely related to the masses of the coordinated metal ions.     

Synthesis and Characterization of Complexes of Copper(II), Nickel(II) and Cobalt(II) with vic-Dioximes Bearing N''-p-Aminobenzoyl Benzaldehyde Hydrazone

Six different arylhydrazone derivatives of p-aminobenzoic hydrazide of vic-dioximes were synthesized by reaction of chloroglyoxime and dichloroglyoxime with N＇-p-aminobenzoyl benzaldehyde, 4-hydroxybenzaldehyde and 4-methoxybenzaldehyde hydrazones, respectively. Metal-ligand （1 ： 2） complexes of vic-dioxime derivatives with Cu（Ⅱ）, Ni（Ⅱ） and Co（Ⅱ） were prepared from corresponding metal acetates. The ligands and their complexes were characterized on the basis of elemental analyses and spectral data. The complexing abilities of these new vic-dioximes toward transition metals of Co（Ⅱ）, Cu（Ⅱ）, Ni（Ⅱ）, Zn（Ⅱ）, Cd（Ⅱ）, Mn（Ⅱ） and Cr（Ⅲ） were determined by solid-liquid extraction studies.     

Spectrothermal studies on Co(II), Ni(II), Cu(II) and Zn(II) salicylato (1,10-phenanthroline) complexes

The cobalt, nickel, copper and zinc atoms in bis(1,10-phenanthroline)bis(salicylato-O)metal(II) monomeric octahedral complexes [M(Hsal)₂(phen)₂]·nH₂O, (M: Co(II), n=1; Cu(II), n=1.5 and Ni(II), Zn(II), n=2) are coordinated by the salicylato monoanion (Hsal) through the carboxyl oxygen in a monodentate fashion and by the 1,10-phenanthroline (phen) molecule through the two amine nitrogen atoms in a bidentate chelating manner. On the basis of the DTG_max, the thermal stability of the hydrated complexes follows order: Ni(II) (149°C)>Co(II) (134°C)>Zn(II) (132°C)>Cu(II) (68°C) in static air atmosphere. In the second stage, the pyrolysis of the anhydrous complexes takes place. The third stage of decomposition is associated with a strong exothermic oxidation process (DTA curves: 410, 453, 500 and 450°C for the Co(II), Ni(II), Cu(II) and Zn(II) complexes, respectively). The final decomposition products, namely CoO, NiO, CuO and ZnO, were identified by IR spectroscopy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation of Schiff’s base complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) and their spectroscopic, magnetic, thermal, and antifungal studies

The potassium salt of salicylidene-DL-alanine (KHL), bis(benzylidene)ethylenediamine (A¹), thiophene-o-carboxaldene-p-toluidine (A²), and its metal complexes of the formula [(M^II(L)(A)(H₂O)] (M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); A = A¹ or A²) are prepared. They are characterized by elemental analysis, magnetic susceptibility measurements, thermogravimetric analysis, and infrared and electronic spectral studies. The electronic spectral and magnetic moment data suggest an octahedral geometry for the complexes. All of these complexes, metal nitrates, fungicides (bavistin and emcarb), and ligands are screened for their antifungal activity against Aspergillus niger, Fusarium oxysporum, and Aspergillus flavus using a plate poison technique. The complexes show higher activity than those of the free ligands, metal nitrate, and the control (DMSO) and moderate activity against bavistin and emcarb. The text was submitted by the authors in English.     

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3,3-dimethylglutaric Acid

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)3,3-dimethylglutarates were investigated and their quantitative composition, solubility in water at 293 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with general formula MC₇H₁₀O₄⋅nH₂O (n=0−2) were recorded and their thermal decomposition in air were studied. During heating the hydrated complexes of Mn(II),Co(II), Ni(II) and Cu(II) are dehydrated in one step and next all the anhydrous complexes decompose to oxides directly (Mn, Co, Zn) or with intermediate formation free metal (Ni,Cu) or oxocarbonates (Cd). The carboxylate groups in the complexes studied are bidentate. The magnetic moments for the paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II)attain values 5.62, 5.25, 2.91 and 1.41 M.B., respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and characterization of novel Cd(II), Zn(II) and Ni(II) complexes with 2-quinolinecarboxaldehyde selenosemicarbazone. Crystal structure of bis(2-quinolinecarboxaldehyde selenosemicarbazonato)nickel(II)

New complexes of Cd(II), Zn(II) and Ni(II) with 2-quinolinecarboxaldehyde selenosemicarbazone (Hqasesc) were synthesized and structurally characterized. The structure of the ligand, Cd(II) and Zn(II) complexes was determined by NMR and IR spectroscopy, elemental microanalysis and molar conductivity measurements. Both complexes occur in solution in two forms, the major tetrahedral and minor octahedral. In the major Cd(II) complex one qasesc⁻ ligand is coordinated as a tridentate, the fourth coordination site being occupied by acetate, while in the major Zn(II) complex two qasesc⁻ ligands are coordinated as bidentates. In both minor complexes two qasesc⁻ ligands are coordinated as tridentates forming the octahedral geometry around the central metal ion. The only paramagnetic complex in the series is Ni(II) complex for which X-ray structure analysis was performed. The complex has the angularly distorted octahedral geometry with two qasesc⁻ ligands coordinated as tridentates, in a similar way as in the minor complexes of Cd(II) and Zn(II).     

Synthesis,spectroscopic and electrochemical studies of copper(II) and cobalt(II) complexes of three unsymmetrical vic -dioximes ligands

Cobalt(II) and copper(II) complexes with three dioxime ligands cyclohexylamine-p-tolylglyoxime (L₁H₂), tert-butyl amine-p-tolylglioxime (L₂H₂) and sec-butylamine-p-tolylglyoxime (L₃H₂), have been prepared. The metal to ligand ratios of the complexes were found to be 1?:?2. The Cu(II) complexes of these ligands are proposed to be square planar; the Co(II) complexes are proposed to be octahedral with water molecules as axial ligands. Ligands and complexes are soluble in common solvents such as DMSO, DMF, CHCl₃ and C₂H₅OH. The ligands have been characterized by elemental analysis, IR, UV-VIS, ¹H?NMR, ¹³C?NMR and thermogravimetric analysis (TGA). The complexes were characterized by elemental analysis, IR, UV-VIS, magnetic susceptibility measurements, thermogravimetric analysis (TGA) and electrochemistry. Electrochemical properties of metal complexes show quasi-reversible one-electron redox processes. However, Co(L₁H)₂ and Cu(L₁H)₂ complexes show another oxidation peak in the positive region. This single irreversible oxidation peak is caused by the cyclic ring of the ligand. Data also revealed that the electron transfer rates of metal complexes with L₁H₂ are higher than the other complexes.     

<Emphasis Type="Italic">bis</Emphasis>(<Emphasis Type="Italic">N,N</Emphasis>-diethylnicotinamide) <Emphasis Type="Italic">p</Emphasis>-chlorobenzoate complexes of Ni(II), Zn(II) and Cd(II)

Three novel mixed ligand complexes of Ni(II), Zn(II) and Cd(II) with p-chlorobenzote and N,N-diethylnicotinamide were synthesised and characterized on the basis of elemental analysis, FTIR spectroscopic analysis, solid state UV-Vis spectrometric and magnetic susceptibility data. The thermal behavior of the complexes was studied by simultaneous TG-DTA methods in static air atmosphere and the mass spectra data were recorded. According to microanalytical results, formulas of complexes are C₃₄H₄₀N₄O₈ClNi, C₃₄H₄₀N₄O₈ClZn and C₃₄H₄₄N₄O₁₀ClCd. The complexes contain two moles of coordination waters, two moles p-chlorobenzoate and two mole N,N-diethylnicotinamide (dena) ligands per formula unit. In these complexes, the p-chlorobenzoate and N,N-diethylnicotinamide behave as monodentate ligand through acidic oxygen and nitrogen of pyridine ring. The decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data. The final decomposition products were found to be as metal oxides.     

Synthesis,characterization and anticancer studies of bis-(N-methyl-1-phenyldithiocarbamato) Cu(II), Zn(II), and Pt(II) complexes: single crystal X-ray structure of the copper complex

Abstract

Cu(II), Pt(II), and Zn(II) complexes of N-methyl-1-phenyldithiocarbamate were synthesized and characterized by FTIR, NMR, UV-visible spectroscopy and elemental analysis. The complexes were formulated as [Cu(L)₂], [Zn(L)₂] and [Pt(L)₂] (where L?=?N-methyl-1-phenyldithio­carbamate) in which two molecules of the ligands coordinate to the metal ions in a bidentate chelating fashion. This is confirmed by elemental analysis and the presence of strong single bands at 952, 951, and 955?cm^?1 for Cu(II), Pt(II), and Zn(II) complexes, respectively, in the FTIR spectra. The electronic spectra of Pt(II) and Cu(II) complexes are consistent with four-coordinate square planar geometry. Single crystal X-ray of [Cu(N-mpDTC)₂] confirmed square planar structural arrangement (CuS₄) in which the ligands are asymmetrically bonded to the Cu(II) ion building a centrosymmetric monomer entity. The S-Cu-S bite angle is 77.95° (3) whereas the intramolecular N–C bond length is 1.318 Å and trans S1¹-Cu-S1?=?S2¹-Cu-S2 is 180°, which are consistent with reported copper thiolates in square planar environment. In vitro antiproliferative activity of the complexes against three human cancer cell lines showed that the zinc complex has better activity compared to Cu and Pt complexes, with IC₅₀ values of 14.28, 22.74 and 20.10?μM against TK10, UACC62, and MC7 cell lines, respectively.     

Synthetic,spectroscopic, fluorescence,and biological investigation of Co(II), Ni(II), Cu(II), and Zn(II) complexes of Schiff bases derived from 3-formyl-2-mercaptoquinolines (Quinol-2-thiones)

Co(II), Ni(II), Cu(II), and Zn(II) complexes have been prepared with Schiff bases derived from 3-formyl-2-mercaptoquinoline and substituted anilines. The prepared Schiff bases and chelates have been characterized by elemental analysis, molar conductance, magnetic susceptibilities, electronic, IR, ¹H-NMR, ESR, cyclic voltammetry, FAB-mass, and thermal studies. The complexes have stoichiometry of the type ML₂ · 2H₂O coordinating through azomethine nitrogen and thiolate sulfur of 2-mercapto quinoline. An enhancement in fluorescence has been noticed in the Zn(II) complexes whereas quenching occurred in the other complexes. The ligands and their metal complexes have been screened in vitro for antibacterial and antifungal activities by MIC methods with biological activity increasing on complexation. Cu(II) complexes show greater bacterial than fungicidal activities. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties of the ligands and their corresponding complexes. Only four compounds have exhibited potent cytotoxic activity against Artemia salina; the other compounds were almost inactive for this assay.     

Syntheses and spectrothermal studies of triethanolamine complexes of Co(II), Ni(II), Cu(II) and Cd(II) squarates

The triethanolamine complexes, [M(tea)₂]sq·nH₂O, (n=2 for Co(II), n=0 for Ni(II), Cu(II) and n=1 for Cd(II), tea=triethanolamine, sq²⁻=squarate), have been synthesized and characterized by elemental analyses, magnetic susceptibility and conductivity measurements, UV-Vis and IR spectra, and thermal analyses techniques (TG, DTG and DTA). The Co(II), Ni(II) and Cu(II) complexes possess octahedral geometry, while the Cd(II) complex is monocapped trigonal prismatic geometry. Dianionic squarate behaves as a counter ion in the complexes. The thermal decomposition of these complexes takes place in three stages: (i) dehydration, (ii) release of the tea ligands and (iii) burning of organic residue. On the basis of the first DTG_max of the decomposition, the thermal stability of the anhydrous complexes follows the order: Ni(II), 289°C>Co(II), 230°C>Cu(II), 226°C>Cu(II), 170°C in static air atmosphere. The final decomposition products — the respective metal oxides — were identified by FTIR spectroscopy.     

Synthesis and characterization of N,N-diethylnicotinamide-acetylsalicylato complexes of Co(II), Ni(II), Cu(II), and Zn(II)

N,N-diethylnicotinamide-acetylsalicylato complexes of Co(II), Ni(II), Cu(II), and Zn(II) were synthesized and investigated by elemental analysis, magnetic susceptibility, solid state UV–Vis, direct injection probe mass spectra, FTIR spectra and thermoanalytic TG-DTG methods. The complexes contain two waters, two acetylsalicylate (asa) and two N,N-diethylnicotinamide (dena) ligands per formula unit. The acetylsalicylate and N,N-diethylnicotinamide are monodentate through acidic oxygen and nitrogen of pyridine ring. Decomposition of each complex starts with dehydration then decomposition of N,N-diethylnicotinamide and acetylsalicylate, respectively. The thermal dehydration of the complexes takes place in one or two steps. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The final decomposition products are found to be metal oxides.     

Spectrothermal studies of 1,10-phenanthroline complexes of Co(II), NI(II), Cu(II) and Cd(II) orotates

The 1,10-phenanthroline (phen) complexes of Co(II), Ni(II), Cu(II) and Cd(II) orotates were synthesized and characterized by elemental analysis, magnetic susceptibility, spectral methods (UV-vis and FTIR) and thermal analysis techniques (TG, DTG and DTA). The Co(II), Ni(II), Cu(II) and Cd(II) ions in diaquabis(1,10-phenanthroline)metal(II) diorotate octahedral complexes [M(H₂O)₂(phen)₂](H₂Or)₂·nH₂O (M=Co(II), n=2.25; Ni(II), n=3; Cu(II) and Cd(II), n=2) are coordinated by two aqua ligands and two moles of phen molecules as chelating ligands through their two nitrogen atoms. The monoanionic orotate behaves as a counter ion in the complexes. On the basis of the first DTG_max, the thermal stability of the hydrated complexes follows the order: Cd(II), 68°C 68°C