18 research outputs found

    Strukturne i elektronske osobine kompleksa nikal(II) sa pentadentatnim diaminotrikarboksilatnim ligandima

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    Helatori su grupa hemijskih jedinjenja koja poseduju dva ili više donorskih atoma. Imaju jedinstvenu osobinu helatacije (multikoordinacije metalnog jona) metalnih jona i atoma. EDTA (etilendiamin-tetrasirćetna kiselina) i njegovi analozi nalaze značajnu primenu kako u detoksifikaciji određenih matrica životne sredine (vode pre svega) zagađenih jonima metala tako i u nuklearnoj medicini za proizvodnju određenih kontrasta pri skeniranju tkiva magnetnom rezonancom. Polazeći od ovih činjenica mi smo za predmet ove disertacije predvideli sintezu nekih nedostajućih kompleksa nikla(II) kako bi smo kompletirali seriju jednostavnih diaminopolikarboksilnih helatnih kompleksa. Metodom rendgenostrukturne analize kao i analizom sintetisanih molekula na bazi savremene kompjuterske hemije sintetisana jedinjenja su sistematski karakterisana. Osnovni cilj bio je da se ispitaju uzročno-posledične veze broja i distribucije petočlanih i šestočlanih helatnih prstenova u kompleksnom molekulu, njihove distribucije u kompleksu, stereohemije i elektronske konfiguracije. U ovoj disertaciji je sintetisano i karakterisano nekoliko različitih tipova helata kao što su: pentadentati diaminotrikarboksilatnog tipa (H3ed3a, H3ed3r, H3eda2r, H31,3-pd3a, H31,2-pd3a i H31,2-pd2ar); heksadentati diaminotetrakarboksilatnog tipa (H41,3-pd3ap). Nagrađeni helati su iskorišćeni za sintezu odgovarajućih kompleksa nikla(II). Na bazi rezultata rendgenske strukturne analize utvrđeno je da su najstabilniji heksadentatni helati oni sa ravnomernim brojem petočlanih i šestočlanih helatnih prstenova. Korelacioni dijagram oktaedarskih devijacija uglova oko metalnog jona i tetraedarskih devijacija oko aminskih atoma azota upravo otkriva činjenicu da postoje kompromisne strukture (stabilni heksadentati) u seriji diaminotetrakarboksilatnih kompleksa dvovalentnih metala. Molekulsko orbitalna analiza ide u prilog ovoj tvrdnji, a što se naročito može zaključiti korelacijom energija prenosa naelektrisanja između fragmenata (metal i edta-tip liganda) i broja petočlanih helatnih prstenova. Kao konačan zaključak može se reći da nesimetričnost liganda (stvorena različitim brojem ili veličinom karboksilnih grupa na atomima azota) prouzrokuje veću ili manju nestabilnost heksadentatnog helatnog kompleksa.Chelators are kind of chemical compounds with two or more donor atoms. They are having a uniqe property to chelate (multicoordination of metal ions) metal ions and atoms. EDTA (ethylenediaminetetraacetic acid) and its analogues are found as a detoxification agents of certain environmental matrix (it is water usually) polluted by metal ions and also as a markers for their use in early cancer discovering. Taking these facts into accounts the synthesis of several missing nickel(II) complexes has been proposed for the main goal of this dissertation in order to make complete the whole set of the simple chelate diamintetracarboxylate complexes. An in-depth analysis has been carried out for all the prepared compounds paying particular attention to the results of X-ray diffraction analysis and modern quantum-mechanical modeling applied to prepared complexes. Basic goal of this work is to investigate causative-consequent realations of the number of five-membered and six-membered chelate rings in the molecule, their distribution in the complex, stereochemistry and electron configurations. Here, several different kinds of chelates such as: pentadentates of diamintricarboxylate-type (H3ed3a, H3ed3р, H3edа2р, H31,3-pd3a, H31,2-pd3a и H31,2-pd2aр); hexadentates of diamintetracarboxylate-type (H41,3-pd3ap)., have been prepared and characterized. The chelating agents have been used for preparation of corresponding nickel(II) complexes. On the basis of X-ray diffraction analysis it was established that the most stable hexadenate chelates are those with equal distribution of five-membered and six-membered chelate rings. The correlation diagram between an octahedral angle deviation around metal ion and tetrahedral angle deviation around coordinated amine nitrogens reveals the fact that compromise structures (stable hexadentates) from whole set of divalent metal diamintetracarboxylate complexes exist. The results of molecular-orbital analysis further support such a claim particularly correlating charge transfer energies between fragments (metal and edtatype of ligand) and the number five-membered rings. As a final conclusion it might be stated that the chelate asymmetry (make by the different number or the size of carboxylate groups attached to amine nitrogens) cause more or less instability of the hexadentate chelate complexes

    First cobalt complexes with methyl pyruvate semi/thiosemicarbazone - synthesis, physico-chemical and structural characterization

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    In the reaction of acetone solutions of CoX2∙nH2O (X = Cl, Br) with methyl pyruvate semi/thiosemicarbazone (Hmps, Hmpt) the first Co(II) complexes with these ligands, i.e., [Co(Hmps)(H2O)X2] (X = Cl (1), Br (2)), [Co(Hmpt)2][CoCl4]∙2H2О (3) and [Co(Hmpt)2]Br2∙Me2CO (4) were obtained. Complexes 1 and 2 represent the first examples of metal complexes of Hmps. All the obtained compounds were characterized by elemental analysis, conductometry, magnetic measurements, and IR spectra, and for complexes 2–4, single crystal X-ray diffraction analysis was also performed. The effective magnetic moments were close to the upper limit (5 μB) for complexes 1 and 2, and close to the lower limit (4.4 μB) for complexes 3 and 4, and as such are characteristic for high-spin Co(II) complexes. Structural analysis showed that both ligands coordinate in a neutral form in a tridentate manner, via the ester oxygen, imine nitrogen and the oxygen atom of the ureido (Hmps), or the sulfur atom of the thioureido group (Hmpt). The central metal atoms are situated in a deformed octahedral coordination environment. Complex 2 has cis-Br configuration, while complexes 3 and 4 have mer-configuration

    CCDC 900433: Experimental Crystal Structure Determination

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    Related Article: S.Belosevic, M.Cendic, A.Meetsma, Z.D.Matovic|2013|Polyhedron|50|473|doi:10.1016/j.poly.2012.11.029,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

    Innovative environmentally friendly technology for copper(II) hydroxide production

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    The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10% phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide

    Crystal structure of trans-diaqua-bis(methyl methylcarbamohydrazonothioato-κ2 N,N′) nickel(II) iodide semihydrate, C6H22N6O2NiS2I2·0.5H2O

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    C6H23I2N6NiO2.50S2, monoclinic, C2/c (no. 15), a = 8.2282(4) Å, b = 21.9200(7) Å, c = 11.4906(4) Å, β = 109.451(4)°, V = 1954.19(14) Å3, Z = 4, Rgt (F) = 0.0322, wRref (F 2) = 0.1113, T = 295

    CCDC 900017: Experimental Crystal Structure Determination

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    Related Article: Svetlana Belošević, Miorad M. Vasojević, Marija S. Jeremić, Auke Meetsma, Zoran D. Matović|2013|J.Coord.Chem.|66|1730|doi:10.1080/00958972.2013.789104,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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