Chemistry Journal of Moldova

Inorganic and coordination chemistry

CARBOXYLATE SUBSTITUTION PATTERN AS STRUCTURAL DIRECTIVE FOR THE FINAL PRODUCTS: SYNTHESIS, STRUCTURE AND PROPERTIES OF [Fe4Ca2O2(μ2-HCCl2COO)10(μ3-HCCl2COO)2(THF)6]

Author(s):

Denis Prodius, Valeriu Mereacre, Maria Gdaniec, Sergiu Shova, Yurii A. Simonov, Nicolae Stanica, Ion Geru, Andrea Caneschi, Constantin Turta


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2008 Volume 3, no.2
Pages: 81-85
Keywords: Iron(III) calcium(II) heterocluster; crystal structure; antiferromagnetic interaction.
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Abstract (JPEG)

DOI: dx.doi.org/10.19261/cjm.2008.03(2).06

Graphical Abstract:
 A novel hexanuclear iron-calcium-oxo complex has been synthesized and characterized by different physico-chemical methods and X-ray single crystal structural analysis: [Fe4Ca2O2(μ2-HCCl2COO)10(μ3-HCCl2COO)2(THF)6].The molecular structure shows that there are two types of coordination for COO- anions: bidentate and tridentate.The corresponding variable temperature susceptibility measurement shows that in the complex there exists an antiferromagnetic interaction (|J12| = |J34| = -71.86 cm-1). The iron(III) high spin state (5/2) is proved by Mössbauer spectroscopy. High magnetic EPR measurements of 1 indicates the presence of S=0 ground state with low-lying S=1 excited state centred around g = 2.0054 ±0.0001.

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SYNTHESIS, CHARACTERIZATION AND CRYSTAL STRUCTURE OF BIS-(2-HYDROXYBENZALDEHYDE)DIAMINOGUANIZONE

Author(s):

Diana Dragancea, Vladimir B. Arion, Sergiu Shova


Field: Inorganic and coordination chemistry
Type: Short communication
Issue: 2008 Volume 3, no.2
Pages: 119-121
Keywords: Schiff base, guanidine, X-ray diffraction.
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DOI:
dx.doi.org/10.19261/cjm.2008.03(2).13

Graphical Abstract:
 The new ligand, bis(2-hydroxybenzaldehyde)diaminoguanizone (1) has been synthesized and characterized by elemental analysis, IR and 1H NMR spectroscopies. The crystal structure of the compound was determined by X-ray diffraction. The ligand C15H15N5O2·C2H5OH crystallizes in the monoclinic space group P21/c with unit cell parameters a = 8.9102(3), b = 10.0357(3), c = 19.7618(6) Å, β = 98.385(2)°, Z = 4, V = 1748.21(9) Å3, R1 = 0.040. The amino form of the ligand adopts a planar conformation stabilized by two intramolecular hydrogen bonds of the type O–H···N, in which the H atoms of the central amino group are directed to the lone-pair regions of the azomethine nitrogen atoms.

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THE STUDY OF THE BIOLOGICAL ACTIVITY OF SOME COBALT(III) DIOXIMATES WITH FLUORINE CONTAINING ANIONS

Author(s):

Eduard Coropceanu, Alexandra Deseatnic, Maria Stratan, Andrei Rija, Olga Bologa, Janna Tiurin, Svetlana Labliuc, Steliana Clapco, Ion Bulhac


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2008 Volume 3, no.2
Pages: 70-80
Keywords: Co(III) dioximates, anions with fluorine, models of biological objects, biostimulating properties, fungi, enzymes.
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DOI:
dx.doi.org/10.19261/cjm.2008.03(2).15

Graphical Abstract:
 It was elaborated the methodology of synthesizing a series of new dioximates of Co(III) with the general formula [Co(DioxH)2(L)2]X⋅nH2O, where DioxH – the dioxime anione: dimethylglyoxime (DH2), 1,2-cyclohexanedionedioxime (NioxH2); L - thiocarbamide (Thio), pyridine (Py), aniline (An), sulphanilamide (Sam);X - [BF4]-, [ZrF6]2-, [TiF6]2-, whose structures have been studied with the help of contemporary physical methods: spectroscopy IR, UV-Vis, RMN 1H, 19F, X-ray analysis. There were elaborated optimal conditions of using cobalt dioximates with fluorine in order to intensify the biosynthesis of amylases and lipases by Aspergillus and Rhizopus strains, respectively. The tested compounds increase the lipolytic activity of Rhizopus arrhisus micromycetes.

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DESIGN AND SYNTHESIS OF COORDINATION COMPOUNDS WITH TETRADENTATE LIGANDS DERIVED FROM ALKYLATED THIOSEMICARBAZIDE

Author(s):

M.Cocu, J. Gradinaru, M. Revenco, E. Rybak-Akimova, N. Gărbălău


Field: Inorganic and coordination chemistry
Type: Review
Issue: 2008 Volume 3, no.2
Pages: 38-46
Keywords: Template synthesis; coordination compounds; 3d-metal complexes; Schiff base; S-alkylisothiosemicarbazide.
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DOI:
dx.doi.org/10.19261/cjm.2008.03(2).16

Graphical Abstract:
 This work is devoted to the investigation of the template reactions of organic compounds derived from S-alkylisothiosemicarbazide and β-dicarbonylic compounds (acetyl(benzoyl)acetone, 2,6-diformylpyridine, 2,6-diformyl-4-methylphenol, 1-hydroxy-2-naphthaldehyde, sodium nitromalonic dialdehyde, 1,1,3,3-tetraetoxypropane, 3-ethoxyacroleine) in the presence of 3d-metal ions, determination of the structure and properties of the prepared complexes. There were elaborated original methods for synthesis of open-chain or macrocyclic coordination compounds of nickel(II), copper(II), oxovanadium(IV) and cobalt(II) with N4, N3O and N2O2 tetradentate ligands. Two types of hexaazamacrocyclic systems with trans- and cis- arrangement of thiosemicarbazide fragments have been obtained using template condensation of different precursors. The biostimulative properties (biomass accumulation and increasing of enzymatic activity) of complexes have been established. Some complexes of nickel(II) have been studied as coloring agents for plastics.

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A THIOLATO-BRIDGED OCTANUCLEAR COPPER(I,II) MIXED- VALENCE COMPLEX WITH N,N,S-TRIDENTATE LIGAND

Author(s):

Takanori Kotera, Tsukasa Sugimoto and Masahiro Mikuriya


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2007 Volume 2, no.1
Pages: 102-107
Keywords: thiolato-bridged complexes; mixed-valence complexes; copper complexes; octanuclear complexes.
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DOI:
dx.doi.org/10.19261/cjm.2007.02(1).06

Graphical Abstract:
 Thiolato-bridged complex [CuI4CuII4(peampt)4Cl8]·2H2O (Hpeampt = 1-(2-pyridylethyl)amino) methylpropane-2-thiol) has been synthesized and characterized by the elemental analysis, IR and UV-vis spectroscopies and magnetic susceptibility measurement. The X-ray crystal structure analysis of this complex shows a localized mixed-valence octanuclear cage structure made up of four trigonal-bipyramidal CuIIN2SCl2, two trigonal CuIS2Cl, and two tetrahedral CuIS2Cl2 coordination sites. Temperature dependence of magnetic susceptibility (4.5— 300 K) shows that a fairly strong antiferromagnetic interaction is operating between the four CuII ions.

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THE STRUCTURE OF THE TETRA-POTASSIUM SALT OF CALIX[4]ARENE DIHYDROXYPHOSPHONIC ACID

Author(s):

Adina N. Lazar, Oksana Danylyuk, Kinga Suwinska and Anthony W. Coleman


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2007 Volume 2, no.1
Pages: 98-101
Keywords: Calixarenes, cation binding, electrostatic interactions.
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DOI:
dx.doi.org/10.19261/cjm.2007.02(1).07

Graphical Abstract: 
The solid-state structure of the tri-potassium calix[4]arene dihydroxyphosphonate salt is presented. In this structure, two potassium cations bridge between layers of dimeric calixarene diphosphonate units and two other potassium cations bridge along the face of the layers. The ubiquitous dimeric association of the calixarenes shows the highest interdigitation value so far observed. As expected, the cations are solvated and are complexed exo with respect to calixarene crown. The octahedral coordination sphere of the potassium cations is formed by two phosphonate groups of the calixarenes and four water molecules. Electrostatic forces represent the major element of interaction in the solid-state system.

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INTERACTION OF QUADRUPLE BONDING RHENIUM UNIT WITH FREE RADICALS

Author(s):

Shtemenko A.V., Tretyak S.Y., Golichenko A.A.


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2007 Volume 2, no.1
Pages: 93-97
Keywords: rhenium, cluster, quadruple bond, free radical, antiradical activity.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2007.02(1).08

Graphical Abstract:
 The interaction of cis-Re2(RCOO)2Cl4, trans-Re2(RCOO)2Cl4, Re2(RCOO)3Cl3 and Re2(RCOO)4Cl2 (where R - alkyl group) with 1,3,5-triphenylverdazyle radical in 1,2-dichlorethane was investigated. It is discovered, that gradual substitution of halogenide ligands by carboxylates in dirhenium(III) clusters led to slowing down of reaction with a radical due to different influence of these ligands on parameters of rhenium - rhenium bond. Presented data showed perspectivity of Re26+-substances applications as therapeutic agents due to their low toxicity and antiradical properties that occured by δ-component of quadruple Re-Re bond electron transition.

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STRUCTURE AND REDOX TRANSFORMATIONS OF IRON(III) COMPLEXES WITH SOME BIOLOGICALLY IMPORTANT INDOLE-3-ALKANOIC ACIDS IN AQUEOUS SOLUTIONS

Author(s):

Krisztina Kovács, Alexander A. Kamnev, Alexei G. Shchelochkov, Ernő Kuzmann, János Mink 3, Tünde Megyes, Attila Vértes


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2007 Volume 2, no.1
Pages: 88-92
Keywords: indole-3-alkanoic acids, auxin phytohormones, iron(III) complexes, coordination structure, redox transformations.
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DOI:
dx.doi.org/10.19261/cjm.2007.02(1).09

Graphical Abstract:
 Interactions of a series of indole-3-alkanoic acids (with n-alkanoic acid side-chains from C1 to C4) with iron(III) in acidic aqueous solutions have been shown to comprise two parallel processes including complexation and redox transformations giving iron(II) hexaaquo complexes. The structure and composition of the reaction products are discussed, as analysed using a combination of instrumental techniques including 57Fe Mössbauer, vibrational and HNMR spectroscopies.

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SPECTROSCOPIC PROPERTIES OF THE Ln-Ge COMPLEXES WITH DIETHYLENETRIAMINEPENTAACETIC ACID

Author(s):

Sergiy Smola, Natalya Rusakova, Elena Martsinko, Inna Seifullina, Yuriy Korovin


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2007 Volume 2, no.1
Pages: 83-87
Keywords: Heteronuclear complexes; Lanthanides; Germanium; DTPA; Luminescence.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2007.02(1).10

Graphical Abstract: 
Four new heteronuclear lanthanide complexes with general formula [Ge(OH)(μ-HDTPA)LnGe(OH) (μ-DTPA)] (Ln = Sm – Dy) were synthesized and subsequently characterized by different physico- chemical methods. The structures of new compounds have been proposed. In considered complexes the 4f-luminescence of three-charged ions of samarium, europium, terbium and dysprosium is realized at UV-excitation. It is noteworthy that it is the first observation of 4f-luminescence in water solutions of heteronuclear f-p-complexes. The comparison of luminescent characteristics of hetero- and homonuclear landthanide complexes is described and discussed as well.

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NANOSCOPIC MOLECULAR CLUSTER V15: HIGH-FIELD EPR AND MAGNETIZATION AT ULTRA-LOW TEMPERATURES

Author(s):

Boris Tsukerblat, Alex Tarantul, Achim Müller


Field: Inorganic and coordination chemistry
Type: Review
Issue: 2007 Volume 2, no.1
Pages: 17-35
Keywords: nanoscopic molecular magnets; V15 cluster; antisymmetric exchange; Jahn- Teller effect.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2007.02(1).17

Graphical Abstract:
 In this paper we give a short overview of our efforts in the understanding of the magnetic properties of the fascinating nanoscopic cluster K6[VIV15As6O42(H2O)]·8H2O (hereafter V15) exhibiting layers of magnetization. We analyze EPR and adiabatic magnetization of the V15 cluster with a triangular VIV3 array causing spin frustration. A model for V15 includes isotropic and antisymmetric (AS) exchange interactions in the general form compatible with the trigonal symmetry. Orientation of the AS vector (but not only its absolute value) is shown to play an important physical role in spin-frustrated systems. We were able to reach perfect fit to the experimental data on the stepwise dependence of magnetization vs. field at ultra-low temperatures. Furthermore, it was possible for the first time to estimate precisely two components of the AS vector coupling constant, namely, in-plane component and the perpendicular part. We show that only intramultiplet transitions in EPR are allowed when the vector of AS exchange is normal to the plane of vanadium triangle, meanwhile the in-plane part of AS exchange gives rise to a series of weak intermultiplet transitions. Experimental data on high-frequency EPR of V15 at low temperatures are discussed. The spin-vibronic effects in trimeric spin frustrated clusters are also studied and an important role of the interplay between the AS exchange and Jahn-Teller interaction is revealed. The results clarify the concept of spin-frustration in view of its magnetic and spectroscopic manifestations in metal clusters.

Downloads: 37