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Seven new complexes of 2-pyridyl ketone Schiff bases N,N′-bis-(pyridin-2-yl-benziliden)-propan-1,3-diamine (bpbpd) and N,N′-bis-[1-(pyridin-2-yl)-etiliden]-propan-1,3-diamine (bpepd) with Co(II), Ni(II), Zn(II) and Cd(II) nitrates and perchlorates were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV–Vis–NIR) as well as magnetic and conductometric measurements. The structure of a cadmium(II) complex was accomplished by single-crystal X-ray diffraction. The Schiff base ligands act as NNNN tetradentate ligands coordinating through pyridine nitrogens and azomethine nitrogens to transition metal ions. The metal ions are six-coordinate for Co(II) and Ni(II), four-coordinate in the case of Zn(II) and eight-coordinate for Cd(II) ions. The coordination sphere of cobalt and nickel complexes is completed by two water molecules, resulting a distorted octahedron. In the case of zinc(II) complexes has been proposed a distorted tetrahedral geometry. The Cd(II) ions are surrounded by a tetradentate Schiff base ligand and two bidentate nitrate anions, leading to a dodecahedral coordination environment. Thermal decomposition of these compounds is a multistage process. Generally, water elimination occurs in the first step and the decomposition of nitrate groups and organic ligands in the next stages. The last step of decomposition for all complexes is strong exothermic and corresponds to oxidative combustion of the Schiff base ligand.

The new 2,2'-[(3,3'-dimethyl[1,1'-biphenyl]-4,4'-diylbis(nitrilomethylidyne)]bis[6-methoxyphenol] (H2L) Schiff base and its complexes with Co(II), Ni(II) and Cu(II) of the type [M(HL)Cl(H2O)] (M = Co(II) or Cu(II)), [M2L(H2O)(4)]X-2 (M = Co(II), X = ClO4 and M = Cu(II), X = NO3) and [M2L(CH3COO)(2)] (M=Co(II), Ni(II), Cu(II)) were synthesised. The ligand and complexes were characterized by elemental analysis, conductivity measurements, magnetic moments at room temperature, IR. NMR, UV-Vis-NIR, EPR spectra and thermogravimetric analysis. Mole ratios of 1:1 or 1:2 between the ligand and metal were determined from the elemental analysis results. Except for the perchlorate complex that behaved as an electrolyte, the other complexes are non-electrolytes. The spectral data suggested tetrahedral, pseudo-tetrahedral or square-planar stereochemistry, which was confirmed by the magnetic behaviour of complexes. The antimicrobial tests indicated fungicide effects for both the ligand and the complexes.

A bidentate/tridentate 5-bromosalycilaldehyde isonicotinoylhydrazone Schiff base was synthesized by condensing 5-bromosalycilaldehyde with isonicotinoylhydrazine. Cu(II), Co(II), Ni(II), Mn(II) and Zn(II) complexes of this chelating ligand were synthesized using nitrates of these metals. The ligand and the complexes were characterized by elemental analysis, UV–Vis, IR and EPR spectroscopy, conductance and magnetic susceptibility measurements, fluorescence, cyclic voltammetry and thermogravimetric analysis. The ligand and Zn(II) complex exhibits solid-state photoluminescence at room temperature.

Five new coordinative compounds that contain mixed ligands (4,4′-bipyridine and methacrylate anion) were synthesized and characterized (elemental analysis, IR and UV–Vis spectroscopy, and thermal studies). The complexes are of the type [M(4,4′-bipy)(C4H5O2)2]·nH2O ((1) M:Mn, n = 0; (2) Co, n = 0.5; (3) M:Ni, n = 1.5; (4) M:Cu, n = 0.5; (5) M:Zn, n = 0.5; 4,4′-bipy: 4,4′-bipyridine; C4H5O2: methacrylate anion). All the tested complexes exhibited very low MIC values against Escherichia coli strains and one compound against Staphylococcusaureus. Besides the specific antimicrobial spectrum, these compounds also inhibited the microbial ability to colonize the inert surfaces, acting as potential anti-adherence and biofilm-controlling agents. The thermal behavior provided confirmation of the complexes' compositions as well as the number and the nature of water molecules and the intervals of thermal stability.

Starting from 5-bromo-N,N′-bis-(salicylidene)-o-tolidine (H2L) new complexes with Co(II), Ni(II) and Cu(II) were synthesised and characterised. The features of complexes have been assigned from microanalytical, IR, UV–Vis–NIR and EPR spectra, magnetic data at room temperature as well as thermal analysis. IR data are in accordance with bischelate nature of the deprotonated ligand that coordinates through azomethinic nitrogen and phenolic oxygen. The electronic spectra display the characteristic pattern of tetrahedral stereochemistry for [CoL]·H2O complex and octahedral one for [NiL(OH2)2]·H2O complex. The electronic spectra correlated with magnetic susceptibility measurements indicate a square-planar surrounding for [ML] (M:Ni, Cu) species, while the EPR spectrum of copper complex sustains the proposed stereochemistry. The thermal analysis evidenced that thermal transformations are complex processes according to TG, DTA and DTG curves including (crystallization or coordination) water elimination, thermolyses and oxidative degradation of Schiff base. All these processes lead to the most stable metallic oxides as final product.

New complexes of type [M(HL)(CH3COO)(OH2)m]·nH2O (where M:Co, m = 2, n = 2; M:Ni, m = 2, n = 1.5; M:Zn, m = 0, n = 2.5 and M:Cd, m = 0, n = 0; H2L:5-bromo-N,N′-bis-(salicylidene)-o-tolidine) have been synthesized and characterized by microanalytical, IR, UV–Vis-NIR and magnetic data. Electronic spectra of Co(II) and Ni(II) complexes are characteristic for an octahedral stereochemistry. The IR spectra indicate a chelate coordination mode for mono-deprotonated Schiff base and a bidentate one for acetate ion. The thermal transformations are complex according to TG and DTA curves including dehydration, acetate decomposition and oxidative degradation of the Schiff base. The final product of decomposition is the most stable metallic oxide.

Ten new mononuclear complexes having general formulae [ML2](ClO4)2, M = Cu(II), Co(II), Ni(II), Mn(II) and Zn(II), [ML2](SO4), M = Co(II), Ni(II) and [ML2(H2O)2](SO4), M = Cu(II), Mn(II) and Zn(II), L = 2-acetyl-pyridyl-isonicotinoylhydrazone have been synthesized and characterized based on elemental analyses, IR spectroscopy, UV–Vis–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The structures of [CoL2](ClO4)2 are accomplished by single crystal X-ray diffraction. The coordination sphere is formed by two N, N, O tridentates 2-acetyl-pyridyl-isonicotinoylhydrazone ligands, or by two N, O bidentate 2-acetyl-pyridyl-isonicotinoylhydrazone and two water molecules. Biological activity studies reveal a moderate activity of complexes against gram-negative and gram-positive bacteria.

New complexes of isonicotinamido-4-chlorobenzalaldimine (INHCBA) with Cu(II), Co(II) and Cd(II), having formula of the type [M(INHCBA)(ac)2]?xH2O (M = Cu2+, x = 1, M = Co2+, x = 2, M = Cd2+, x = 0, ac = CH3COO-), and with Cu(II), Mn(II) and Zn(II), having formula of the type [M(INHCBA)2(H2O)2]SO4?xH2O (M = Cu2+, Mn2+, x = 2 and Zn2+ x = 2.5) were synthesized and characterized by analytical and physico-chemical techniques, i.e., elemental analyses, IR, UV-VIS- NIR and EPR spectroscopy as well as thermal analysis and the determination of the molar conductivity and magnetic moments. The thermal behaviour of complexes was studied by thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The ligand behaves as bidentate NO, being coordinated through the azomethine nitrogen and carbonylic oxygen. The heats of decomposition, ?H, associated with the exothermal effects, were also determined.

A new one-dimensional (1-D) cadmium(II) complex [Cd(ppk)(N3)2] n (1) has been synthesized and characterized. X-ray crystal structure study reveals that 1 is composed of a 1-D cadmium(II) chain with double µ1,1 azido bridges. Three different cadmiums, Cd(1), Cd(2), and Cd(3), may be found along the chain.

New complexes of isonicotinoylhydrazone-9-anthraldehyde with Cu(II), Co(II) and Ni(II) have been prepared and characterized by analytical and physico-chemical techniques, such as elemental and thermal analyses, magnetic susceptibility and conductivity measurements, and electronic, EPR and IR spectral studies. The infrared spectral studies revealed the bidentate or monodentate nature of the Schiff base in the complexes; the pyridine nitrogen does not participate in the coordination. A tetrahedral geometry is suggested for the nitrate-complexes and an octahedral geometry for the others. Thermal studies support the chemical formulation of these complexes.

Eight new complexes of Cu(II), Co(II), Ni(II) and Zn(II) with isonicotinic acid hydrazide (isoniazid, (INH)) and isonicotinic acid (1-naphthylmethylene) hydrazide (INNMH), having the formula of the type [M(INH)(ac)2] or [M(INNMH)(ac)2] (M = Co(II), Ni(II) and Zn(II)) and [Cu(INH)(ac)2]2, [Cu(INNMH)(ac)2]2, were synthesized and characterized. All complexes were characterized based on elemental analyses, and IR, UV-VIS-NIR and EPR spectroscopy, as well as by thermal analysis and determination of their molar conductivity and magnetic moments. The structure of INNMH was established by single crystal X-ray analysis. In all complexes, both ligands were coordinated to the metal via N and O. The complexes of Cu (II) were dimeric, with four bridges between acetate ions and Cu(II).

New complexes of 2-benzoyl-pyridil-isonicotinoylhydrazone (L) with Cu(II), Co(II), Ni(II) and Mn(II), having formula of type [ML2] SO4·xH2O (M = Cu2+, Co2+, Ni2+, x = 2 and M = Mn2+, x = 3), have been synthesised and characterised. All complexes were characterised on the basis of elemental analyses, IR spectroscopy, UV–VIS–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The thermal behaviour of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The structure of L hydrazone was established by X-ray study on single crystal. The ligand works as tridentate NNO, being coordinated through the azomethine nitrogen, the pyridine nitrogen and carbonylic oxygen. Heats of decomposition, ΔH, associated with the exothermal effects were also determined.

New copper (II) complexes of Schiff bases with 1,2-di(imino-2-aminomethylpyridil)ethane with the general composition CuLX m (H2O) x , [L = Schiff base, X = Cl−, Br−, NO3 −, ClO4 −, CH3COO−, m = 2; X = SO4 2−, m = 1] were prepared by template synthesis. The complexes were characterized by elemental analysis, conductivity measurements, magnetic moments, IR, UV–VIS and EPR spectra. The thermal behavior of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Infrared spectra of all complexes are in good agreement with the coordination of a neutral tetradentate N4 ligand to the cooper (II) through azomethinic and pyridinic nitrogen. Magnetic, EPR and electronic spectral studies show a monomeric distorted octahedral geometry for all Cu(II) complexes. Conductance measurements suggest the non-electrolytic nature of the compounds, except for copper (II) nitrate and perchlorate complexes which are 1:2 electrolytes. Heats of decomposition, ΔH, associated with the exothermal effects were also determined.

Complexes of Cu(II), Ni(II), Co(II) with the 9-anthraldehyde iso- nicotinoyl hydrazone ligand (HL 1 ) and the 3,5-di-tert-butyl-4-hydroxybenz- aldehyde isonicotinoyl hydrazone ligand (H2L 2 ) were synthesized by the tem- plate method. The complexes were characterized by analytical analysis, IR, UV-Vis and ESR spectroscopy, magnetic measurements, conductometry and thermal analysis and the two ligands by 1 H-NMR spectroscopy. From the elemental analysis, 1:2 (metal:ligand) stoichiometry for the complexes of Cu(II), Ni(II) with the ligands HL 1 and H2L 2 and 1:1 (metal:ligand) stoichio- metry for the complex of Co(II) with the ligand HL 1 are proposed. The molar conductance data showed that the complexes are non-electrolytes. The mag- netic susceptibility results coupled with the electronic and ESR spectra sugges- ted a distorted octahedral geometry for the complexes Ni(II)/HL 1 , Ni(II)/H2L 2 and Cu(II)/H2L 2 , a tetrahedral stereochemistry for the complex Cu/HL 1 and a square-planar geometry for the complex Co/HL 1 . The IR spectra demonstrated the bidentate coordination of the ligands HL 1 and H2L 2 by the O=C amide oxygen and the azomethine nitrogen, as well as monodentate coordination of the ligand HL 1 by the azomethine nitrogen in the Cu(II)complex. The anti- bacterial activity of the ligands and their metallic complexes were tested against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae.

Pyridine derivative complexes are widely employed as biological active materials especially as antibacterial agents. Five transition metal(II) mpk com- plexes (mpk = methyl 2-pyridyl ketone) were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV-Vis-NIR) and conductometric measurements. The general formulae established from experimental data were found to be (M(mpk)2(NO3)2)� xH2 O( x = 0 for M = Cd(II), Zn(II), x = 2 for M = Cu(II)) and (M(mpk)2(H2O)2)(NO3)2 (M = Co(II), Ni(II)). These compositions were further confirmed by thermal analysis and their thermal stability in dynamic air atmo- sphere investigated.

Four new mononuclear complexes having general formulae [M(ppk)2(H2O)2](NO3)2 (M═Co (1); M═Ni (2); M═Zn (3)) and [M(ppk)2(NO3)2] (4) (ppk = phenyl-2-pyridil-ketone) have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy. The structures of 3 and 4 were accomplished by single crystal X-ray diffraction. The crystallographic investigation of 3 reveals monomeric, dicationic units in which the zinc(II) ion is six-coordinated. The coordination sphere is formed by two N, O bidentate phenyl-2-pyridil-ketone ligands and two water molecules. The crystal structure of 4 consists of monomeric units in which the cadmium atom is eight-coordinated. Both the organic ligand and nitrate groups are bidentate chelators. Biological activity studies reveal a moderate activity of complexes against Gram negative and Gram positive bacteria.

Three new mononuclear complexes [Co(2-Acpy)2(H2O)2](NO3)2 (1), [Ni(2-Acpy)2(H2O)2](NO3)2 (2) and [Cd(2-Acpy)2(NO3)2] (3) (2-Acpy = 2-acetylpyridine) have been synthesized and characterized by elemental analysis, IR and UV–Vis spectroscopy. The structures of 1 and 3 were accomplished by single crystal X-ray diffraction. Crystallographic investigation of 1 reveals monomeric, dicationic units in which the cobalt(II) ion is six-coordinate. The coordination sphere is formed by two N, O bidentate acetylpyridine ligands and two water molecules. The crystal structure of 3 consists of monomeric units in which the cadmium is eight-coordinate. Both the organic ligand and nitrate groups are bidentate chelators. The supramolecular solid-state architecture is sustained by π–π interactions.

Copper sulfide (Cu x S, x= 1.8-2) thin films were deposited at 285 °C by spray pyrolysis from aqueous and alcoholic solutions of copper (II) chloride and thiourea with different Cu:S molar ratio. The XRD analysis showed that deposited films are chemically close to chalcocite (Cu 2 S) or to mixtures of copper-rich phases (Cu 2 S, Cu 1.8 S, Cu 1.9375 S) in which chalcocite or digenite (Cu 1.8 S) is predominant. The films containing the single phase Cu 2 S are denser and more homogenous than the films formed by two or more phases. The current-voltage (I-V) dark curves showed the diode behavior of the films, depending on the film thickness.

Thin films of CuS (covellite) were deposited onto TCO (SnO2:F) glass by Spray Pyrolysis (SP) technique. Aqueous and water:alcohol (ethanol, 1-propanol) solutions of copper(II) chloride and thiourea with different Cu/S molar ratio have been used as precursors. The substrate temperature was varied from 185°C to 285°C. The structural and the morphological characterization of the films has been carried out by Raman spectroscopy and Scanning Electron Microscopy. The X-Ray Diffraction analysis of as-grown films showed the single-phase covellite, with hexagonal crystal structure built around three preferred orientations corresponding to (102), (103) and (110) atomic planes. The dense morphology of CuS films with large crystallites/aggregates suggest that crystal growth is the limiting step in the films deposition, at 235 °C and at 285 °C, from precursors' solution containing water or mixtures of water:alcohol as solvents. The growth of CuS thin films by spray pyrolysis is favored by increasing both the alcohol concentration and the deposition temperature.

The complexes of the type SnCl4(HL)·EtOH and SnCl2L2 (HL 1 : the Schiff base resulted in 1:1 condensation of isatin and aniline; HL 2 : the Schiff base resulted in 1:1 condensation of isatin and p-toluidine) have been synthesized and characterized. The thermal analysis of the new ligands and complexes has evidenced the thermal intervals of stability and also the thermal effects that accompany them. The Schiff bases thermal transformations consist in phase transitions, Carom–N bond cleavage and thermolysis processes. The different nature of the complexes generates their different thermal behaviour. The complexes lead in three steps to SnO2 and in all cases the Schiff bases degradation generates a pyrrolidone-coordinated derivative. As for the SnCl4(HL)·EtOH complexes, the SnCl4 formed during the last step is involved in two competitive processes, one consists in their volatilisation while the other one leads to SnO2. As result the SnO2 residue is smaller than the theoretically expected.

Metal complexes ML2Cl2, where M is Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) and L is Schiff base formed by condensation of 2-thiophenecarboxaldehyde and 2-aminopyridine, N-[2-thienylmethylidene]-2-arninopyridine (TNAPY), have been prepared and characterized by elemental analysis, magnetic and spectroscopic measurements. IR and NMR spectra show that the nitrogen of the azomethyne group and the sulphur of the thiophene ring take part in coordination. Magnetic, ESR and electronic spectral studies show a distorted octahedral structure for the Fe(II), Co(II), Ni(II) and Cu(II) complexes and a tetrahedral geometry for the Zn(II) and Cd(II) complexes. Conductance measurements suggest the non-electrolytic nature of the complexes, with the exception of the Zn(TNAPY)2Cl2 and Cd(TNAPY)2Cl2 compounds which are 1:2 electrolytes.

Divalent 3d metal complexes with formyl-vanilline derivatives, of lite type ML2 or ML2X2 (M = Cu(II), Co(II); X = Cl), were sythesized by reaction of the corresponding metal(II) chlorides with 1-[3-formyl-4-methoxy-6-hidroxybemilydene]-2-phenazinoyllhydrazine, (FDFH), 1-benzilydene-2-phenazinoyhydrazine, (BFH), and 3-formyl-5,6-dihydroxybemilydenc-2-nitro-1--methylaniline, (FBAH). The novel complexes were characterized by ESR, IR, electronic spectroscopy, molar electric conductibility measurements and magnctk studies. These compounds appear to bn hexacoordinated.

Cobalt (II), nickel (II), copper (II), cadmium (II), and mercury(II) complexes with phenyl-2-pyridyl-ketone as ligand were synthesized at room temperature in ethanolic solution. The donor atoms and the possible geometry of the complexes were determined by means of elemental analysis, molar conductivities, IR, electronic, and EPR spectroscopies, magnetic measurements, and thermogravimmetric analysis.

The paper present the research made in obtaining of dense, homogeneous and relative uniform thin films of CuxS and SnS with specific structural and electrical properties, as p-type semiconductors and absorbers for solid state solar cells. The films are deposited via Spray Pyrolysis Deposition (SPD), and analyzed by XRD, SEM and dark I-V curves.

University of Bucharest, Faculty of Chemistry, Department of Inorganic Chemistry, 23 Dumbrava Rosie, Bucuresti, Romania E-mail: veronica.pop@k.ro Manuscript received 14 November 2002, accepted 31 January 2003 In order to obtain new potential antioxidants with molecular mass lower than those of the metal-proteins, a new copper(II) compound with mixed ligands, L-histidine and urea was synthesised. The compounds containing only one of the two mentioned ligands, Cu-urea and Cu-L-histidine was also synthesised as intermediates in the synthesis of the compound with mixed ligands or for comparative purposes. The spectral analysis indicates an axial symmetry of the Cull ions in the compound with mixed ligands. Stability studies, in time and in different pH-conditions, were carried out by absorption electronic spectroscopy; the results revealed satisfactory stability in time, at the pH of the physiologic scrum of the compounds with mixed ligands; the compound is also stable in aqueous solutions at pH 7.2-5.5 . The study of compatibility with physiological mediums indicates that the compound displays significant lypophilic character.

University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Str. Dumbrava Rosie nr. 23, 70254-Bucharest, Romania University Politehnica Bucharest, Faculty of Industrial Chemistry, Str. Polizu nr. 1, 78126-Bucharest, Romania Institute of Physical Chemistry, Coordination Chemistry Laboratory, Spl. Independentei nr. 202, 77208-Bucharest, Romania Manuscript received 2 March 2000, revised 18 October 2000. accepted 10 February 2001 Some new complexes of CrIII, CoII, NiII, CuII and CdII have been synthesized with a tetradentate Schiff base, glyoxilidenc-bis-2-aminoethylpyridine. An octahedral geometry has been proposed for the CrIII and NiII complexes and tetrahedral geometry for the rest of the compounds.&nbsp

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest Department of Inorganic Chemistry, Faculty of Sciences, Universtiy of Craiova, A. I. Cuza, 13, Romania Manuscript received 15 June 1999, accepted 3 September 1999 The complexes of CoII, NiII and CuII with Schiff base derived from 2-thiophenecarboxaldehyde and 2-monopropanolamine have been prepared. The octahedral structure has been assigned to these compounds, excepting the CuII compound which has a distorted octahedral geometry.