J. Gažo

Bio: J. Gažo is an academic researcher. The author has contributed to research in topics: Nickel & Thermal decomposition. The author has an hindex of 6, co-authored 7 publications receiving 107 citations.

Heterogeneous reactions of solid nickel(II) complexes, III

Abstract: The stoichiometry of thermal decomposition was studied for the following compounds: Ni(pyNO)Cl2H2O (I), (pyNO=pyridine N-oxide), Ni(2-MepyNO)Cl2·2H2O (II), Ni(3-MepyNo)Cl2·2H2O (III) and Ni(4-MepyNO)2Cl2·C2H5OH (IV). The heating of the compounds led first to the release of H2O molecules (or C2H5OH molecules), with the formation of Ni(pyNO)Cl2 (V), Ni(2-MepyNO)Cl2(VI), Ni(3-MepyNO)Cl2 (VII) and Ni(4-MepyNO)2Cl2 (VIII). In the next stage, decomposition of the heterocyclic liugands set in. The compositions and spectral and magnetic properties of these complexes indicate their dimeric (II, III, IV, VIII) of polymeric (I, V, VI, VII) structure with coordinated molecules of H2O (or C2H5OH).

Heterogeneous reactions of solid nickel(II) complexes, V: Thermal decomposition of compounds of the type Ni(NCS)2L2. Part C: Kinetic study of pseudooctahedral complexes

Abstract: The kinetics of the thermal decomposition of solid complexes of the type Ni(NCS)2L2 (L=pyridine,β-picoline and quinoline), of pseudooctahedral configuration, were studied by using isothermal methods, on the basis of losses of weight, in the temperature range 90–191‡. The most suitable reaction order for all the complexes under investigation was found to ben=2/3, i.e. the total decomposition rate is determined by the chemical process proper. The calculated values ofEa(in kcal · mole−1) decrease in the following order: Ni(NCS)2py2 (29.4)>Ni(NCS)2(β-pic)2 (27.6)>Ni(NCS)2Q2 (24.3). With increasing volume of the ligand L the reaction rate also increases, and this suggests that the reaction proceeds by dissociative activation. For all the investigated complexes it was found that δH>EA; this may be explained by a several-step mechanism and the complex Ni(NCS)2L is then considered an intermediate.RésuméOn a étudié la cinétique de la décomposition thermique des complexes solides du type Ni(NCS)2L2 (L=pyridine,β-picoline et quinoléine) de configuration pseudo-octaédrique, d'après la perte de poids en régime isotherme entre 90 – 191‡C. L'ordre de la réaction obtenu pour les complexes examinés s'élève àn=2/3, c'est-à-dire que la vitesse de la décomposition totale est déterminée par la réaction chimique elle-mÊme. Les valeurs calculées pourEa (en kcal · mol−1) diminuent suivant l'ordre Ni(NCS)2py2 (29.4)>Ni(NCS)2 (β-pic)2 (27.6)>Ni(NCS)2Q2 (24.3). La vitesse de réaction croÎt lorsque le volume des ligands L augmente ce qui permet de suggérer un mécanisme réactionnel avec activation de la dissociation. On a trouvé δH>Ea pour tous les complexes examinés ce qui peut s'expliquer par un mécanisme avec plusieurs étapes, le complexe Ni(NCS)2L étant alors considéré comme produit intermédiaire.ZusammenfassungDie Kinetik der thermischen Zersetzung der festen Komplexe vom Typ Ni(NCS)2L2 (L=Pyridin,β-Picolin oder Chinolin) und pseudooktaedrischer Konfiguration wurde durch isotherme Methoden auf Grund der Gewichtsverluste zwischen 90–191‡ untersucht. Die geeignetste Reaktionsordnung wurde fürn=2/3 gefunden, d.h. die totale Zersetzungsgeschwindigkeit wird durch den eigentlichen chemischen Vorgang bestimmt. Die errechnetenEa Werte (in kcal · mol−1) nehmen in folgender Reihenfolge ab: Ni(NCS)2py2 (29.4)>Ni(NCS)2(β-pic)2 (27.6)>Ni(NCS)2Q2 (24.3). Mit zunehmendem Volumen der Liganden nimmt also die Reaktionsgeschwindigkeit zu, der Reaktionsverlauf richtet sich folglich nach der dissoziativen Aktivierung. Für alle untersuchten Komplexe ergab sich δH>Ea. Dies läßt sich durch einen Mehrstufenmechanismus erklären, wobei der Komplex Ni(NCS)2L als Intermediär gilt.РЕжУМЕИжУЧЕНА кИНЕтИкА тЕР МОРАспАДА тВЕРДых кОМплЕксОВ тИпА Ni(NCS)2L2 (L== п ИРИДИН,β-пИкОлИН И хИНОлИН) п сЕВДООктАЁДРИЧЕскО И кОНФИгУРАцИИ пРИ ИжО тЕРМИЧЕскИх УслОВИьх НА ОсНОВАНИ И пОтЕРИ ВЕсА В ОБлАст И тЕМпЕРАтУРы 90–191‡C. УстА НОВлЕНО, ЧтО НАИБОлЕЕ сООтВЕт стВУУЩИИ пОРьДОк РЕА кцИИ Дль ВсЕх ИжУЧЕННых кОМпл ЕксОВn=2/3, т. Е. ОБЩАь скОРОсть РАс пАДА ОпРЕДЕльЕтсь спЕцИФИЧЕскИМ хИМИЧ ЕскИМ пРОцЕссОМ. РАсс ЧИтАННыЕ ВЕлИЧИНыEa(ь ккАл · МОл−1) УМЕНьшАУтсь В слЕДУУЩЕМ пОРьДкЕ: Ni(NCS)2py2 (29.4) > Ni(NCS)2(β-pic)2 (27.6) > Ni(NCS)2Q2 (24.3). с УВЕлИЧИ ВАУЩИМсь ОБЩЕМОМ лИгАНДА L скОРОсть РЕА кцИИ тАкжЕ УВЕлИЧИВА Етсь. ЁтО пОжВОльЕт пРЕДпОлОж Ить, ЧтО хОД РЕАкцИИ сООтВЕтстВУ Ет ДИссОцИАтИВНОИ Ак тИВАцИИ. НАИДЕНО, ЧтО Дль ВсЕх И жУЧЕННых кОМплЕксОВδН>Ea. ЁтО ОБЩьсНьЕтсь МНОгОстУпЕНЧАтыМ МЕхАНИжМОМ, пРИ кОтОР ОМ кОМплЕкс Ni(NCS)2L пРОМЕжУтОЧНыИ пРОД Укт.

Heterogeneous reactions of solid nickel(II) complexes, IV: Thermal decomposition of compounds of the type Ni(NCS)2L2 Part B: Thermochemical properties

Abstract: The decomposition heats (ΔH) for complexes of the type Ni(NCS)2L2 were studied by means of a differential scanning calorimeter. From the decreasing values ofΔH the following order has been established:a) for pseudooctahedral complexes: py >β-pic > > Q; andb) for square-planar complexes: 2,6-lut > Q >α-pic. The results obtained are compared with the data from the TG, DTG, and DTA curves.RésuméDétermination par analyse enthalpique différentielle des chaleurs de décomposition (ΔH) des complexes de formule générale Ni(SCN)2L2. Le classement des valeurs deΔH par ordre décroissant montre que pour les complexes pseudo-octaédriques py >gb-pic > Q et que pour les complexes plans carrés lut-2,6 > Q >α-pic. Comparaison de ces résultats avec les données des courbes TG, TGD et ATD.ZusammenfassungEs erfolgte die Bestimmung der Zersetzungswärmen (ΔH) der Komplexe vom Typ Ni(NCS)2L2 durch die Differential Scanning Calorimetrie. Mit abnehmendenΔH Werten ergab sich die Reihenfolge:a) Pseudooktaedrische Komplexe: Py >ß-Pic > Q;b) Quadratische Komplexe: 2,6-Lut. > Q >α-Pic. Ergebnisse mit aus den DTA, TG und DTG-Kurven gewonnenen Resultaten wurden verglichen.РезюмеС помощью сканирующе го калориметра изуче на теплота распада (ΔH) дл я комплексов типа Ni(NCS)2L2. В р яду уменьшающих вели чинΔH найден следующий пор ядок: а) для псевдооктаэдри ческих комплексов ру >β-pic > Q; и б) для планарных комплексов 2,6 lut > Q >α-Pic. Полу ченные результаты сравнены с данными, по лученными исходя из кривых ТГ, ДТ Г и ДТА.

[1]Benzofuro[3,2- c ]pyridine synthesis and coordination reactions

Abstract: (E)-3-(1-Benzofuran-2-yl)propenoic acid (1) was prepared from 1-benzofuran-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide 2, which was cyclized by heating in diphenyl ether to [1]benzofuro[3,2-c]pyridine-1(2H)-one (3). This compound was aromatized with phosphorus oxychloride to chloroderivative 4 which was reduced with zinc and acetic acid to the title compound 5. [1]Benzofuro[3,2-c]pyridine-2-oxide (6) was synthesized by reaction of 5 with 3-chloroperoxybenzoic acid in dichloromethane. Treatment of 6 with benzoyl chloride and potassium cyanide (Reissert-Henze reaction) was shown to produce the corresponding [1]benzofuro[3,2-c]pyridine-1-carbonitrile (7). The title compound was used for preparation of complexes Cu2(ac)4(bfp)2 (8) and CoCl2(bfp)2 (9), where ac=CH3CO 2 − and bfp=[1]benzofuro[3,2-c]pyridine. Both oxygen atom of carboxylate ions is used in the coordination to Cu(II). Thermal properties of the complexes 8 and 9 have been studied by TG and DTA and both complexes exhibited high thermal stability while complex 9 are thermally more stable than complex 8.

Thermal properties, induction period, interfacial energy and nucleation parameters of solution grown benzophenone

Abstract: Benzophenone is a well-known material, which exhibits non-linear optical (NLO) property. It has been grown by solution technique adopting slow evaporation method from solvents CHCl3, CCl4 for the first time. Solubility metastable zone width and inductions periods of benzophenone in CHCl3 and CCl4 were determined. Interfacial tension values at two different temperatures for various super saturations, such as 1.10, 1.15, 1.20 and 1.25 were determined using induction period. From interfacial tension values, the nucleation parameters, such as the radius of the critical nuclei (r*), the free energy change for the formation of a critical nucleus (ΔG*) and the number of molecules in the critical nucleus were also calculated for benzophenone in CHCl3 and CCl4 at two different temperature. The effect of surface tension, viscosity, density of these solvents are correlated with interfacial tension. The metastable zone width is also correlated with interfacial tension. The solution grown crystals were carefully harvested and subjected to various characterization studies to check its purity and to determine its applicability.

Synthesis, characterization and fungicidal activity of zinc diethyldithiocarbamate and phosphate

Abstract: Zinc diethyldithiocarbamate, zinc diethyldithiocarbamate-phosphate and zinc phosphate have been synthesized. They have been characterized using DTA-TG, IR spectra and X-ray. The dithiocarbamate and phosphate contents have been determined spectrophotometrically and volumetrically, respectively. Fungicidal activity of the compounds has been tested by well diffusion method using fungi Fusarium sp.

Heterogeneous reactions of solid nickel(II) complexes, III

Abstract: The stoichiometry of thermal decomposition was studied for the following compounds: Ni(pyNO)Cl2H2O (I), (pyNO=pyridine N-oxide), Ni(2-MepyNO)Cl2·2H2O (II), Ni(3-MepyNo)Cl2·2H2O (III) and Ni(4-MepyNO)2Cl2·C2H5OH (IV). The heating of the compounds led first to the release of H2O molecules (or C2H5OH molecules), with the formation of Ni(pyNO)Cl2 (V), Ni(2-MepyNO)Cl2(VI), Ni(3-MepyNO)Cl2 (VII) and Ni(4-MepyNO)2Cl2 (VIII). In the next stage, decomposition of the heterocyclic liugands set in. The compositions and spectral and magnetic properties of these complexes indicate their dimeric (II, III, IV, VIII) of polymeric (I, V, VI, VII) structure with coordinated molecules of H2O (or C2H5OH).