Synthesis,characterization and antifungal activity of glycylglycine Schiff base complexes of 3d transition metal ions

Summary Two new Schiff bases, N-4-hydroxysalicylidene-glycylglycine (K·GGRS·H₂O), N-O-vanillal-glycylglycine (K· GGVS·3H₂O) and their manganese(II), cobalt(II), nickel(II) and copper(II) complexes have been synthesized and characterized by elemental analysis, t.g.a., molar conductance, i.r. and u.v. spectral studies. The ¹³Cn.m.r. spectrum of one of the Schiff base ligands has been recorded. The results show that the ligand is coordinated to the central metal ion via amide nitrogen, imino nitrogen, phenolic oxygen and carboxyl oxygen to form a quadridentate complexes. Some of the complexes exhibit strong inhibitory action towards Candida albicans and Cryptococcus neoformans.     

Two azo pigments based on β‐naphthol

There has been much discussion in the literature of the azo–hydrazone tautomerism of pigments. All commercial azo pigments with β‐naphthol as the coupling compound adopt the hydrazone tautomeric form (Ph—NH—N=C) in the solid state. In contrast, the red pigments 1‐[4‐(dimethylamino)phenyldiazenyl]‐2‐naphthol, C₁₈H₁₇N₃O, (1a), and 1‐[4‐(diethylamino)phenyldiazenyl]‐2‐naphthol, C₂₀H₂₁N₃O, (1b), have been reported to be azo tautomers or a mixture of azo and hydrazone tautomers in the solid state. To prove these observations, both compounds were synthesized, recrystallized and their crystal structures redetermined by single‐crystal structure analysis. Difference electron‐density maps show that the H atoms of the hydroxyl groups are indeed bonded to the O atoms. Nevertheless, a small amount of the hydrazone form seems to be present. Hence, the compounds are close to being `real' azo compounds. Compound (1a) crystallizes with a herring‐bone structure and compound (1b) forms a rare double herring‐bone structure.     

Conductivity and Morphology of Composite Solid Electrolytes SnO2· nH2O–Heteropolycompounds

The structure and surface characteristics of SnO₂ · 1.5H₂O and composite materials with heteropolycompounds (HPC) formulated as SnO₂ · 1.5H₂O–HPC (where HPC = (NH₄)₃PW₁₂O₄₀ · nH₂O, (NH₄)₂HPW₁₂O₄₀ · nH₂O, and H₃PW₁₂O₄₀ · nH₂O) are studied by scanning tunneling microscopy. Hydrated tin oxide is characterized by a globular structure which differs substantially from the morphology of composite materials. The conductivity is studied as a function of both the temperature and humidity of environment and the composition of composite materials. For composite materials containing ((NH₄)₂HPW₁₂O₄₀ · nH₂O, the conductivity is shown to vary monotonously with the composition and obey the mixture rule. Introduction of (NH₄)₃PW₁₂O₄₀ · nH₂O to a composite is found to cause an extremely fast conductivity decay, whereas addition of H₃PW₁₂O₄₀ · nH₂O results in the appearance of a plateau on the conductivity vs. composition curve. The explanation given to the phenomena observed is based on the mechanism of protonic transport in heteropolycompounds.     

Synthesis,spectroscopy and thermal analysis of nickel(II), palladium(II) and copper(II) complexes with N,N′-bis(2-hydroxyethyl)-oxamide

Summary The new complexes K₂[Ni(H₂heo)₂]·3H₂O, K₂[Pd-(H₂heo)₂], K₂[Cu(heo)]·3H₂O and [Cu₂(heo)·2H₂O] {heo = [(CONCH₂CH₂O)₂]^4-} were prepared and characterized by chemical analyses, conductivity measurements, thermogravimetry, magnetic susceptibility and i.r. and u.v. spectroscopy.Monomeric square planar structures with MN₄ coordination spheres are found for the nickel and palladium complex anions.For copper, two different complexes were identified. In slightly alkaline media, a green insoluble nonelectrolyte [Cu₂(heo)·2H₂O] was prepared; the two copper(II) centres are bridged by the tetra-deprotonated ligand in a trans-planar configuration with the H₂O molecules strongly coordinated to the copper(II). The copper(II) monomer has been prepared in strong alkaline media, this anion also contains the tetra-deprotonated ligand in a planar trans form.     

Metal complexes of phytohormones. Part II. Copper(II) complexes of 6-benzylaminopurine

Summary Copper(II) complexes with 6-benzylaminopurine (BAPH) of the types Cu(BAPH)₂(ClO₄)₂·2H₂O (1) Cu(BAP)₂·4H₂O (2), and Cu(BAPH₂)Cl₃·MeOH (3), have been synthesized and characterized by conductivity, magnetic measurements, i.r., electronic and e.s.r. spectroscopy.     

Spectroscopic and voltammetric studies of the cobalt (II) complex of Morin bound to calf thymus DNA

Absorption and emission spectra, viscometric and electrochemical studies have been carried out on the interaction of Morin (2, 3, 4, 5, 7-pentahydroxyflavone) and its Co complex, CoL₂·3H₂O[L = Morin (2-OH group deprotonated)], with calf thymus DNA. In the presence of DNA, the complex exhibits a hypochromism in the u.v.–vis. spectra and a large enhancement in emission spectra suggests that the complex binds to DNA via a weak partial intercalation, revealed by competitive experiments, viscosity and by electrochemical studies. The binding constant is ca. 2 × 10³ M^–1 at 20 °C. Both ZnL₂·3H₂O and CoL₂·3H₂O complexes have the same molecular structure, ZnL₂·3H₂O shows the spectral characteristics and electrochemical behaviour which agrees with observations for other intercalators in the presence and absence of DNA, whereas the CoL₂·3H₂O complex shows different spectral characteristics and electrochemical behaviour to that of ZnL₂·3H₂O, which suggests that the mode and affinity of the complex CoL₂·3H₂O binding to DNA are different from that of ZnL₂·3H₂O. Both ZnL₂·3H₂O and CoL₂·3H₂O complexes exhibited different antitumour activity. So the binding mode and affinity of complexes to DNA may play an important role in determining the antitumour activity.     

Synthesis and characterisation of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes of tridentate dibasic ONO donor Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde/2-hydroxy-1-naphthaldehyde

Summary The syntheses of several new coordination complexes of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) with new Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde or 2-hydroxy-1-naphthaldehyde are described. These complexes have been characterised by elemental analyses, electrical conductance, magnetic susceptibility, molecular weight, i.r. and electronic spectra. The Schiff bases behave as dibasic and tridentate ligands coordinating through the ONO donor system and form complexes of the types NiL · 3H₂O, MnL · 2H₂O, CoL · 2H₂O, CuL, ZnL · H₂O, UO₂L · MeOH and MoO₂L · MeOH (where LH₂ = Schiff base). The copper(II) complexes exhibit subnormal magnetic moments indicating the presence of an antiferromagnetic exchange interaction, whereas the nickel(II), cobalt(II) and manganese(II) complexes behave normally at room temperature. Zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes are diamagnetic; the zinc (II) complexes are tetrahedral, the copper(II) complexes are square planar, all the other complexes are octahedral. Thev(C=N),v(C-O),v(N-N) andv(C-S) shifts have been measured in order to locate the Schiff base coordination sites.     

Some compounds of iron(III) with bidentate bases

Summary The iron(III) compound, FeCl(OH)(MeCO₂) · MeCO₂H · 0.5 H₂O, (1), interacts with the sample bidentate ligand, 2,2-bipyridyl (bipy), to form an aduct, Fe₂Cl₂(OH)₂(MeCO₂)₂ · (bipy). By the loss of protons, anthranilic (anthH) and salicylic (salH₂) acids behave as uninegative charged ligands to give FeCl(anth)₂ · H₂O and FcCl(salH)₂ · H₂O, respectively. The former decomposes on heatingin vacuo to form Fe₂O(anth)₄ while the latter yields Fe₂O(sal)₂. Acetylacetone (acacH) and 8-hydroxyquinoline (quinH) give FeCl(acac)₂ and FeCl(quin)₂ · (quinH). The latter desolvates at 140°/10^–4 torr to form FeCl(quin)₂. l.r. spectra, thermal decomposition, molar conductance and magnetic susceptibility studies at room temperature have been used to characterize these compounds.     

Die Kristallstruktur des Calciumazid-Dihydrates

Single crystals of Ca(N₃)₂·2 H₂O have been prepared from aqueous solutions at room temperature. The crystals are monoclinic,a=1 159.0 (3),b=614.2 (2),c=785.5 (2) pm, =106.52 (2)°,Z=4, space group P2₁/n. The crystal structure was determined by single crystal X-ray diffraction (1 109 Mo-K-reflexions,R=0.052). Calcium atoms are surrounded by four azide groups and four water molecules. The coordination polyhedra are antiprism which are sharing azide groups and water molecules to form layers. The lattice constants and powder pattern agree well with values reported earlier for Ca(N₃)₂ · 1.5 H₂O [1]. It was also shown, that Sr(N₃)₂ · 2 H₂O is isotypic with Ca(N₃)₂ · 2 H₂O.

     

Synthesis, characterization and antitumour properties of metal(II) solid complexes with Morin

Summary Six metal(II) complexes with Morin ML₂·nH₂O [L = Morin(2-OH group deprotonated); M = Mn, Co, Ni, Cu, Zn, or Cd; n = 2 or 3] have been synthesized and characterized by elemental analysis, molar conductance, i.r., ¹H-n.m.r., t.g.-d.t.a and u.v.-vis. spectroscopic techniques and by fluorescence analysis. Comparative antitumour activities of Morin·2H₂O and two complexes [ZnL₂·3H₂O and CuL₂·2H₂O] were tested by in vitro screening. The results show that the inhibitory ratio of complexes against the tested tumour cells was higher than that of Morin.     

Synthesis,characterization and antiviral activity of nickel-substituted rare earth molybdosilicic heteropoly blues

A series of novel heteropoly blues, Ln₂H₂[SiMo₁₁Ni(H₂O)O₃₉] · nH₂O (Ln = La, Ce, Pr, Nd, Sm, or Gd), had been prepared and characterized by elemental analysis, i.r., u.v., c.v., t.g.–d.t.a., XPS, ²⁹Si-n.m.r., electrochemistry and magnetic susceptibility. Compared with non-reduced heteropolyoxometallates, the heteropoly blue anion in Ln₂H₂[SiMo₁₁Ni(H₂O)O₃₉] · nH₂O still retains the -Keggin structure but with a slight distortion, with Ni and Mo atoms distributed statistically in the crystal. The antiviral activities of these complexes have been studied using tomato mosaic virus. Ln₂H₂[SiMo₁₁Ni(H₂O)O₃₉] · nH₂O show excellent antivirus activities, and the cure rate reaches to 80–90%.     

Deprotonated and non-deprotonated cobalt(II) complexes of the bis-amide tetradentate ligand N,N′-(dipicolyl)-1,8-naphthylene diamine. Three different modes of coordination by the ligand

The preparation and some properties of the cobalt(II) complexes Co(LH₂)Cl₂·2H₂O, Co(LH₂(NCS)₂ and CoL·H₂O (whereLH₂=N,N-(dipicolyl)-1,8-naphthylenediamine) are reported. On the basis of magnetic moments, visible reflectance and IR data, the structure is proposed to be pseudo-octahedral for Co(LH₂)Cl₂·2 H₂O, pseudo-tetrahedral for Co(LH₂)(NCS)₂ and square planar for CoL·H₂O.

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Deprotonierte und Nicht-deprotonierte Co(II)-Komplexe des vierzähnigen Bisamid-Liganden N,N-(Dipicolyl)-1,8-naphthyldiamin. Drei verschiedene Koordinationstypen

Zusammenfassung Es werden die Darstellung und einige Eigenschaften der Kobalt(II)-Komplexe Co(LH₂)Cl₂·2 H₂O, Co(LH₂)(NCS)₂ und CoL·H₂O [LH₂=N,N-(dipicolyl)-1,8-naphthylendiamin] diskutiert. Auf der Grundlage von magnetischen Momenten, von Daten der sichtbaren Reflektions-und IR-Spektren wird eine pseudooctaedrische Struktur für Co(LH₂)Cl₂·2H₂O, eine pseudotetraedrische für Co(LH₂)(NCS)₂ und eine planar-quadratische für CoL·H₂O vorgeschlagen.

     

Antioxidative and anti-tumour activities of solid quercetin metal(II) complexes

Six metal(II) complexes with quercetin ML₂ · nH₂O [L = quercetin (3-OH group deprotonated); M = Mn, Co, Ni, Cu, Zn, and Pb; n = 2 or 3] have been prepared and characterized by elemental analysis, complexometric titration, thermal analysis, conductivity, i.r., u.v., ¹H-n.m.r. and fluorescence spectral techniques as well as by cyclic voltammetry. The antioxidative and anti-tumour activities of quercetin · 2H₂O and the complexes were tested by both the MTT and SRB methods. The results show that the suppression ratios of the complexes against the tested tumour cells are superior to quercetin · 2H₂O. The effect of ZnL₂ · 3H₂O reacting with calf thymus DNA was studied by fluorescence methods. The Zn-complex binding to DNA has been determined by fluorescence titration in 0.05 M Tris-HCl, 0.5 M NaCl buffer (pHb = 7.0). The results indicate that the interaction of the complex with DNA is very evident.     

Structural studies of 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone complexes

Summary Complexes of Cu^II, Ni^II, Co^II, Zn^II, Cd^II and Hg^II with 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone (H₂BATS) are reported and have been characterized by elemental analyses, molar conductivities, magnetic moments, spectral (visible, i.r.) and thermal (d.t.a., t.g., d.t.g.) measurements. I.r. spectra show that H₂BATS behaves as a dianionic, monoanionic or neutral tetradentate ligand or as a monoanionic tridentate ligand. [Cu₂(H₂BATS)Cl₂]·2H₂O and [Cu₂(H₂BATS)Ac₂]·2H₂O complexes are diamagnetic while [Co(HBATS)OH]·2H₂O and [Ni(HBATS)OH]·2H₂O are octahedral. All the complexes are non-electrolytes. Generally, the solid metal acetate complexes have a unique decomposition exotherm profile which can be used as a rapid and sensitive tool for the detection of acetate-containing complexes.     

Iron(III) complexes withN-Methyl-4-mercaptopiperidine

Summary Complexes of iron(III), containingN-methyl-4-mercaptopiperidine in its zwitterionic form (HRS), of stoichiometry Fe(HRS)₄XA₄ · nD, Fe(HRS)₃(BPh₄)₃ · 3DMF and (Fe(HRS)SO₄)₂SO₄ · 3MeOH · 2H₂O (X=Cl or NO₃; A=BPh₄ or PF₆; D=H₂O, MeOH or DMF) have been prepared and characterized by i.r. and electronic spectra, magnetic susceptibilities at room temperature and by cyclic voltammetry measurements.     

Synthesis and characterisation of cobalt(III) complexes with 1,1-dimethylethylenediamine (1,1-dmen) and 1,2-propanediamine (pn)

Two stable diamine complexes [Co(1,1-dmen)₂(NCS)₂]SCN · (H₂O)_1.5 (1) and [Co(pn)₂(NCS)₂]SCN · (H₂O)_1.5 (2) have been synthesised and characterised by elemental analysis, i.r. and electronic spectra and t.g.a. The structure of (1) has been confirmed by single-crystal X-ray diffraction and reveals that the cobalt complex has octahedral geometry and consists of two crystallographically independent cations, both situated on centres of inversion. In the crystal structure of (1), free H₂O molecules and SCN^– ions form an extensive hydrogen bonding network with the cation. It is an ordered pseudo-polymorph of a previous structure determination. Both (1) and (2) are diamagnetic.     

Binuclear cyanide-bridged cobalt–iron complexes

Three new binuclear complexes: [(NO)(CN)₄FeCN–Co(en)₂] · H₂O (1), [(NO)(CN)₄FeCN–Co(pn)₂] · 2H₂O (2), and [(NO)(CN)₄FeCN–Co(tn)₂] · 3H₂O (3) (en = ethylenediamine, pn = 1,2-diaminopropane; tn = 1,3-diaminopropane) have been prepared and their properties studies by i.r., u.v. spectroscopy, cyclic voltammetry, and by magnetic measurements.     

The thermal decomposition of some Cr(III) complexes

The thermal decomposition reactions of the following chromium(III) complexes were investigated: Cr(CH₃COO)₃·2 H₂O, [C_r3O(CH₃COO)₆(H₂O)₃]Cl·2 H₂O and [Cr₃O(CH₂ClCOO)₆(H₂O)₃]Cl·6H₂O. Simultaneous TG/DTG/DTA were applied nonisothermal conditions. From the recorded curves, the activation energiesE _a were calculated for all the thermal decomposition steps. Appropriate chemical reactions were attributed to the thermal effects, with consideration to the X-ray diffraction and IR spectra results.

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Zusammenfassung Für die Untersuchung der thermischen Zersetzungsreaktion der Chrom(III)-Komplexe Cr(CH₃COO)₃·2H₂O [C_r3O(CH₃COO)₆·(H₂O)₃]Cl2H₂O und [C_r3O(CH₂ClCOO)₆·(H₂O)₃]C₁₆H₂O wurde simultane TG/DTG/DTA unter nichtisothermen Bedingungen eingesetzt. Ausgehend von den aufgezeichneten Kurven wurden für alle Schritte der Zersetzungsreaktion die E_a-Werte berechnet. In Übereinstimmung mit röntgenographischen und IR-spektroskopischen Ergebnissen wurden den thermischen Effekten passende chemische Reaktionen zugeordnet.

     

Preparation and cytotoxic activity of nickel(II) complexes with 6-benzylaminopurine derivatives

Nickel(II) complexes with 6-benzylaminopurine (BAP) derivatives, namely 6-(3-chlorobenzylamino)purine (HL₁), 6-(4-chlorobenzylamino)purine (HL₂) and 6-(4-fluorobenzylamino)purine (HL₃), have been prepared and characterized by elemental analyses, i.r., u.v.–v.i.s., ES+ and FAB+ mass spectroscopy, magnetic susceptibility and conductivity measurements, and by thermal analysis. The complexes are: [Ni(L₁(H₂O)₂Cl] · H₂O, [Ni(L₁)(H₂O)-(NO₃)] · H₂O, [Ni(L₂)(H₂O)₂Cl], [Ni(L₂)(H₂O)₂(NO₃)] · H₂O, [Ni(HL₂)(H₂O)Cl₂] · EtOH and [Ni(L₃)(H₂O)₂Cl]. They have been tested in vitro for their possible cytotoxic activity against G-361 (human malignant melanoma), HOS (human osteogenic sarcoma), K-562 (human chronic myelogenous leukemia) and MCF-7 (human breast adenocarcinoma) cell lines.     

Thermal and calorimetric studies of M(IO3)2·6H2O and M(IO3)2·6D2O forM 2+=Ca2+ and Sr2+

Thermal and calorimetric studies were carried out on M(IO₃)₂·6H₂O and M(IO₃)₂·6D₂O forM ²⁺=Ca²⁺ and Sr²⁺, using DTA and DSC methods. The thermal behaviour of the ordinary and deuterated hydrates is outlined and the differences observed between them are discussed. The enthalpies of the phase transitions were determined. The H _f ^o for Ca(IO₃)₂·6H₂O, Ca(IO₃)₂·6H₂O(D₂O) and Sr(IO₃)₂·6H₂O(D₂O) were calculated from the H _deh data and comments are made on the isotope effect observed.

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Zusammenfassung Mittels DTA- und DSC-Methoden wurden Me(IO₃)₂·6H₂O und Me(IO₃)₂·6D₂O (mitMe ²⁺=Ca²⁺ und Sr²⁺) thermisch und kalorimetrisch untersucht. Es wird ein Überblick über das thermische Verhalten ordentlicher und deuterierter Hydrate gegeben, in dem auch die Unterschiede zwischen beiden diskutiert werden. Die Enthalpien der untersuchten Phasenumwandlungen wurden bestimmt. Aus den Daten für H_deh wurde H_f von Ca(IO₃)₂·6H₂O, Ca(IO₃)₂H₂O(D₂O) und Sr(IO₃)₂·6H₂O(D₂O) berechnet und Bemerkungen zum beobachteten Isotopeneffektes gemacht.