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1

Prekatalizatory oligomeryzacji olefin oparte na kationach chromu(III) oraz kobaltu(II) : właściwości fizykochemiczne oraz katalityczne

Malinowski Jacek, Drzeżdżon Joanna, Sikorski Artur, Jacewicz Dagmara Elżbieta

Wiadomości Chemiczne

|

2022

|

[Z] 76, 11-12

943--962

EN

The introduction describes the most important facts about the development of polyolefins. This is followed by a description of the role of polyolefins and the most important applications in industry and everyday life. The paper presents new, highly active precatalysts for oligomerization of olefins. These are coordination compounds based on chromium(III) cation, anions of various polycarboxylic acids and auxiliary ligands, such as 1,10-phenanthroline or 2,2'-bipyridyl. This review presents their crystallographic structures and basic parameters describing the elementary cell. The catalytic properties of the obtained oligomerization products using chromium(III) coordination compounds by MALDI-TOF MS are described. In conclusion, the presented precatalysts are compared with others described in the literature.

2

Sorption and reduction of chromiumion ions by the chelating ion exchanger Diaion CR20

Wójcik Grzegorz

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 6

1382--1393

EN

The chelating ion exchanger Diaion CR20 was applied for removal of chromium(VI) ions in the pH range from 1.5 to 10 and in the presence of 1 M H2SO4. The speciation analysis was used to predict the reduction process. Reduction of chromium(VI) to chromium (III) was observed during the chromium(VI) ions sorption. The kinetic parameters for the pseudo-first-order and pseudo-second-order, Elovich and intraparticle diffusion models were calculated. The most common three isotherm models: Freundlich, Langmuir and Dubinin-Radushkevich were used to describe chromium(VI) uptake. It was proved that the polyamine groups present in selected ion exchanger are able to sorb both chromium(VI) and (III) ions. The maximal sorption capacity towards chromium(VI) ions was estimated at pH 1.5 – 169.49 mg Cr(VI)/g and 159.31 mg Cr(VI)/g in 1 M H2SO4. Both static and column methods were used in the investigations.

3

Zastosowanie spektrometrii mas jonów wtórnych z analizatorem czasu przelotu (TOF-SIMS) do badań odporności korozyjnej warstw konwersyjnych wytworzonych działaniem chromu(III) na powłoki cynkowe na stali węglowej

Rogowski J., Socha M., Socha A.

Przemysł Chemiczny

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2017

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T. 96, nr 11

2317--2323

PL

Metodą spektrometrii mas jonów wtórnych z analizatorem czasu przelotu (TOF-SIMS) zanalizowano skład chemiczny warstw konwersyjnych wytworzonych na próbkach stali węglowej pokrytych warstwą cynku. Odporność badanych warstw na korozję wyznaczono na podstawie krzywych polaryzacyjnych, pomiaru ich impedancji oraz z wykorzystaniem komory solnej. Stwierdzono, że w procesie pasywacji zachodzi reakcja między związkami chromu a cynkiem, prowadząca do zmiany składu chemicznego powierzchni, w tym utworzenia mieszanych tlenków ZnCrxOy. Wykazano korelacje szybkości korozji wyznaczonej metodą elektrochemiczną oraz w komorze solnej z zawartością jonów fluorkowych w warstwie pasywnej oraz rezystancją warstwy porowatej.

EN

Samples of C steel coated with a 8 μm thick layer of Zn were treated with HNO₃ soln. and then passivated in com. Cr(III) salt solns. to produce conversion layers. Corrosion resistance of the layers was detd. on basis of polarization curves, impedance measurements and salt chamber tests. The chem. compn. of the layers was analyzed by using TOF-SIMS. The Cr compds. reacting with Zn during passivation resulted in formation of mixed ZnCrxOy oxides. Furthermore, the corrosion rate detd. by electrochem. methods and saline chamber test depended on the content of F ions in the passive layer.

4

Abexperimental analysis of the transport mechanism of chromium(III) ions in the polymer inclusion membrane system stract

Rajewski J., Łobodzin P.

Problemy Eksploatacji

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2016

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no. 1

105--117

EN

The paper presents an experimental analysis of the mechanism of chromium(III) ion transport in a polymer inclusion membrane (PIM). First of all, the influence of the carrier concentration on chromium(III) transport kinetics through polymer inclusion membranes is investigated. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) was used as a carrier. The initial Cr(III) concentration was changed. The authors indicate that the transport efficiency of Cr(III) depends on the D2EHPA concentration in the PIM. Regardless of the initial chromium(III) concentration, for experimental conditions, there was an optimal range of carrier concentration, somewhere between 30–50% v/v, for which the process was the most effective. The authors propose the “jumping” transport as the dominant transport mechanism in the investigated system.

PL

W pracy dokonano eksperymentalnej analizy mechanizmu transportu jonów chromu(III) w polimerowej membranie inkluzyjnej (PIM). W pierwszej kolejności zbadano wpływ stężenia przenośnika na kinetykę transportu jonów chromu (III) przez polimerową membrane inkluzyjną. Jako przenośnika jonów Cr(III) użyto kwasu di(2-etylkoheksylo) fosforowego (D2EHPA). Badania prowadzono przy różnym stężeniu początkowym jonów chromu. Autorzy wskazują, że efektywność transportu jest zależna od stężenia D2EHPA w PIM. Niezależnie od początkowego stężenia Cr(III) w warunkach prowadzenia badań wyznaczono zakres stężeń przenośnika 30–50% v/v, przy których transport zachodził najefektywniej. Zaproponowano mechanizm przeskokowy jako transport dominujący.

5

Removal of Cr(III) ions from salt solution by nanofiltration: experimental and modelling analysis

Kowalik-Klimczak A., Zalewski M., Gierycz P.

Polish Journal of Chemical Technology

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2016

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Vol. 18, nr 3

10--16

EN

The aim of this study was experimental and modelling analysis of the nanofiltration process used for the removal of chromium(III) ions from salt solution characterized by low pH. The experimental results were interpreted with Donnan and Steric Partitioning Pore (DSP) model based on the extended Nernst-Planck equation. In this model, one of the main parameters, describing retention of ions by the membrane, is pore dielectric constant. In this work, it was identified for various process pressures and feed compositions. The obtained results showed the satisfactory agreement between the experimental and modelling data. It means that the DSP model may be helpful for the monitoring of nanofiltration process applied for treatment of chromium tannery wastewater.

6

Extraction properties of tetraheptylresorcin[4]arenes in relation to Cr(III) ions

Konczyk J., Miroshnychenko S., Kozlowski C.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

835--844

EN

Resorcin[4]arene-based ligand bearing four heptyl chains at the lower rim of the molecule was prepared and modified by four tetradietoxyphosphoryl groups in the upper rim. The compounds obtained were characterized by NMR spectroscopy and their extractability toward chromium(III) ions was studied. The influence of process parameters such as the pH of aqueous phase, agitation time and also extractant’s structure and concentration on efficiency of Cr(III) ions solvent extraction is presented. The highest yield of Cr(III) solvent extraction was obtained for two-hour agitation time of 5.010−4 M metal solution of pH 5.0 and 5.010−3 M chloroform solution of the tetradietoxyphosphorylated derivative of heptyl-resorcin[4]arene. Under optimal conditions, competitive solvent extraction of Cr(III), Zn(II), and Cd(II) ions was performed and separation factor values were established as 77.0 and 24.9 for Cr(III)/Cd(II) and Cr(III)/Zn(II) ions pairs, respectively. The stoichiometry of formed metal-ligand complexes 1:1 was found by classical slope analysis method.

7

Biosorption of Cr(III) from aqueous solution by activated sludge

Wierzba S., Korbecki T.

Ecological Chemistry and Engineering. A

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2016

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Vol. 23, nr 3

337--346

EN

The biosorption of Cr(III) from aqueous solution using activated sludge (AS) microorganisms was investigated under various experimental conditions regarding pH and temperature. Biosorption equilibrium parameters were determined based on the Langmuir and Freundlich isotherm model. The kinetic parameters were established using the equations of pseudo-first order and pseudo-second order. Moreover thermodynamic parameters have been calculated. Langmuir isotherm provided a better fit to the equilibrium data. The maximum experimentally determined sorption capacity 26.95 mg · g–1 obtained at 25oC and pH 5.0. The kinetics model of pseudo-second order row has been better describing experimental data. The negative value of free Gibbs energy (ΔG0) proves spontaneous Cr(III) biosorption by AS biomass and its decreasing along with temperature increase. The negative value of enthalpy (ΔH0) and entropy (ΔS0) indicates exothermic process and limitation of degree of freedom Cr(III) ions on the interphase surface solution/biosorbent. FT-IR spectroscopy analysis indicated the contribution of carboxylate groups towards the biosorption of Cr(III) by AS.

PL

W pracy badano proces biosorpcji jonów chromu(III) z roztworów wodnych przez mikroorganizmy osadu czynnego (OC), w różnych warunkach pH i temperatury. Parametry równowagowe biosorpcji wyznaczono w oparciu o modele izoterm Langmuira i Freundlicha. Parametry kinetyczne określono za pomocą równań pseudopierwszego i pseudodrugiego rzędu. Obliczono również parametry termodynamiczne procesu. Izoterma Langmuira lepiej opisywała dane równowagowe. Maksymalna pojemność sorpcyjna wyznaczona eksperymentalnie wynosiła 26,95 mg · g–1 przy 25oC i pH 5,0. Model kinetyki pseudodrugiego rzędu lepiej opisywał dane doświadczalne. Ujemna wartość energii swobodnej Gibbsa (ΔG0) świadczyła o spontaniczności biosorpcji Cr(III) przez biomasę OC i jej spadku wraz ze wzrostem temperatury. Ujemna wartość entalpii (ΔH0) i entropii (ΔS0) wskazywała na egzotermiczność procesu i ograniczenie stopni swobody jonów Cr(III) na powierzchni międzyfazowej roztwór/biosorbent. Analiza FT-IR wykazała udział grup karboksylanowych w biosorpcji Cr(III) przez OC.

8

Mobilność chromu w strukturze artezyjskiej doliny Krynki w świetle wyników modelowania pola filtracji

Małecki J.J., Gruszczyński T.

Biuletyn Państwowego Instytutu Geologicznego

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2012

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nr 452

167--180

PL

Skażenie środowiska chromem, podobnie jak innymi metalami ciężkimi, ze względu na adsorpcję metali na koloidach próchniczych i minerałach ilastych, najdłużej utrzymuje się w glebach. W wodach w warunkach utleniających chrom może występować w formach sześciododatnich, głównie anionowych CrO42– i Cr2O72–, a w warunkach redukcyjnych i w środowisku kwaśnym dominują formy trójdodatnie, przede wszystkim kationy CrOH2+ i Cr3+. Interesującym poligonem badawczym do prześledzenia migracji chromu w środowisku gruntowo-wodnym jest zlewnia rzeki Krynki, zlokalizowana we wschodniej części województwa podlaskiego. Przez wiele lat ścieki z licznych zakładów garbarskich zanieczyszczały środowisko, czego efektem jest nagromadzenie ponadnormatywnych ilości metali ciężkich, w tym przede wszystkim chromu, w glebach i osadach dennych. Ponadto górna część zlewni Krynki stanowi unikatowy w obrębie utworów czwartorzędowych przykład występowania wód pod ciśnieniem artezyjskim. Aktualny układ ciśnień w niecce sprawia, że wody te nie są bezpośrednio narażone na zanieczyszczenie metalami z poziomu przypowierzchniowego. Jednak w efekcie ich zbyt intensywnej eksploatacji, w wyniku odwrócenia ciśnień, powstałoby realne zagrożenie migracji zanieczyszczeń z osadów dennych i gleb do wód poziomu artezyjskiego. Jednym z podstawowych celów badawczych było określenie możliwości migracji chromu w strukturze artezyjskiej w wyniku zmian ciśnień.

EN

Environmental contamination with chromium, as well as by other heavy metals, remains the longest in soils due to the adsorption of metals on humic colloids and clay minerals. In the water, in oxidizing conditions, chromium may be present in a heptavalent, mainly anionic forms of CrO42–, Cr2O72–, and under reducing conditions and in an acidic environment, trivalent chromium dominates, mainly CrOH2+ and Cr3+ cations. An interesting testing area for investigations of chromium migration in the soil-water environment is the Krynka River drainage basin located in the eastern part of Podlasie Voivodeship. For many years, sewage from a number of tanning plants polluted the environment, resulting in accumulation of abnormal amounts of heavy metals, including in particular chromium, in soils and bottom sediments. Furthermore, the upper part of the Krynka drainage basin is a unique example of, the presence of artesian water within the Quaternary deposits. Due to the current pressure system in the basin, the water is presently not directly exposed to metal pollution from the near-surface. However, as a result of their excessive exploitation, due to a reversal of pressures, there would be a real threat of migration of pollutants from bottom sediments and soils through the groundwater to the artesian water level. One of the primary purposes of the research was to determine the possibility of chromium migration in the artesian system due to changes in the pressure.

9

Usuwanie jonów chromu (III) z roztworów wodnych techniką ultrafiltracji micelarnej (MEUF)

Konopczyńska B., Staszak K., Prochaska K.

Inżynieria i Aparatura Chemiczna

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2011

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Nr 5

58-59

PL

W prezentowanej pracy przedstawiono fragment badań dotyczących możliwości zastosowania techniki micelarnej ultrafiltracji do usuwania jonów Cr(IH) z roztworów wodnych. Analizowano wpływ stężenia chromu(III) w roztworze wyjściowym oraz wpływ typu i ilości surfaktantu dodanego do separowanego układu na efektywność i wydajność procesu MEUE.

EN

The paper presents a fragment of study on the applicability of micellar enhanced ultrafiltration technique for removal of Cr(III) ions from aqueous solution. The influence of the concentration of chromium(III) in the initial solution and the influence of the type and amount of surfactant added to the separated system on the effectiveness and efficiency of the MEUF process were analized.

10

Effect of Some Substances on Content of Selected Components in Soils Contaminated with Chromium

Wyszkowski M., Radziemska M.

Ecological Chemistry and Engineering. A

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2011

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Vol. 18, nr 11

1497-1504

EN

The effect of soil contamination with increasing doses of tri- and hexavalent chromium (0, 25, 50, 100 and 150 mg Cr kg–1 of soil) was determined on various properties of soil after cultivation of plants and the neutralizing effect of compost (3 %), zeolite (3 %) and calcium oxide (1 HA) on the contamination. Triand hexavalent chromium in soil, as well as the substances added to it significantly modified its basic physicochemical properties. Contamination of soil with tri- and hexavalent chromium reduced soil acidity and increased total exchangeable base cations, cation exchange capacity and base saturation. Hexavalent chromium had a greater effect on pH and hydrolytic acidity (but not on the total exchangeable base cation or cation exchange capacity) than trivalent forms of the metal. An addition of calcium oxide to the soil effectively neutralized the effect of contamination on the tested properties as it significantly decreased hydrolytic acidity. However, it also reduced total exchangeable base cations and cation exchange capacity – only with chromium(III) as compared with the control series (with no additives). The effect of the other substances was weaker and more positive in the case of compost than zeolite, especially in the objects with hexavalent chromium.

PL

W doświadczeniu wazonowym badano wpływ zanieczyszczenia gleby wzrastającymi dawkami chromu trój- i sześciowartościowego (0, 25, 50, 100 i 150 [mg Cr kg-1 gleby]) na wybrane właściwości gleby po zbiorze roślin oraz oddziaływania kompostu (3 %), zeolitu (3 %) i tlenku wapnia (1 Hh) na łagodzenie skutków tego zanieczyszczenia. Zanieczyszczenie gleby chromem trój- i sześciowartościowym miało duży wpływ na pH, kwasowość hydrolityczną i pozostałe właściwości badanej gleby. Zanieczyszczenie gleby chromem trój- i sześciowartościowym spowodowało zmniejszenie zakwaszenia gleby oraz zwiększenie sumy wymiennych kationów zasadowych, całkowitej pojemności wymiennej i stopnia wysycenia kationami zasadowymi. Chrom sześciowartościowy w stosunku do trójwartościowego znacznie silniej oddziaływał na pH i kwasowość hydrolityczną, w odróżnieniu od sumy wymiennych kationów zasadowych i całkowitej pojemności wymiennej. Dodatek do gleby tlenku wapnia skutecznie łagodził oddziaływanie zanieczyszczenia gleby chromem na badane właściwości gleby, gdyż znacznie zmniejszył kwasowość hydrolityczną. Jednakże ograniczył także sumę wymiennych kationów zasadowych oraz pojemność wymienną - tylko w przypadku chromu(III), w porównaniu z serią kontrolną (bez dodatków). Wpływ pozostałych substancji był mniejszy i bardziej korzystny w przypadku kompostu niż zeolitu, szczególnie w obiektach z chromem sześciowartościowym.

11

Synthesis and Properties of New Bimetallic Complexes of General Formula: [Cu(diamine)2][Cr(NCS)4(NH3)2]2

Wrzeszcz G., Grzebielucha T.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1575-1582

EN

Four new thiocyanato bridged heteronuclear com plexes of general formula [Cu(diamine)2][Cr(NCS)4(NH3)2]2, where diamine = ethylenediamine (en) (1), 1,2-di -amino propane (pn) (2), 1,3-diaminopropane (tn) (3) and N-methylethylenediamine (men) (4) have been prepared in solid state by treatment of [Cr(NCS)4(NH3)2]– with corresponding cationic [Cu(diamine)2]2+ complex in anaqueous solutions. They have been characterized by elemental and thermal analysis, spectroscopic methods (IR, UV-Vis, EPR), and variable-temperature magnetic susceptibility measurements. The formation of end-to-end thiocyanato bridges between tetragonal (elongated octahedral) Cu(II) and octahedral Cr(III) is evident from IR and electronic spectra. The EPR spectra measured at room temperature on solid samples (1 and 3) show very broad and symmetric signal at g = 2.02 and 2.07, respectively. Magnetic data reveal the absence of significant exchange inter actions between the Cr(III) and Cu(II) ions in all studied complexes (1–4). Thermal decomposition after ammonia release is multistage and yields CuO, and Cr2O3 as final products.

12

Hexacyanochromates(III) and Hexacyanocobaltates(III) of Copper(II) with Tridentate and Tetradentate N-donor Ligands. Crystal Structure of [{Cu(ept)}3{Co(CN)6}2]źH2O (ept = N-(2-aminoethyl)-1,3-propandiamine)

Mamulová Kutláková K., Smékal Z., Neels A., Önal M., Šindelář Z.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 10

1707-1716

EN

The following complexes [{Cu(ept)}3{Cr(CN)6}2]ź5H2O, [{Cu(hatce)}3{Cr(CN)6}2]ź ź15H2O, [{Cu(hatco)}3{Cr(CN)6}2]ź14H2O, [{Cu(ept)}3{Co(CN)6}2]ź5H2O, [{Cu(hatce)}3{Co(CN)6}2]ź18H2O and [{Cu(medpt)}3{Co(CN)6}2]źH2O (ept = N-(2-amino ethyl)-1,3-propandiamine, hatce = 1,3,6,10,12,15-hexaaza tricyclo [13.3.1.16,10]eicosane, hatco = 1,3,6,9,11,14-hexaaza tricyclo[12.2.1.16,9]octadecane and medpt = N,N-bis-(3-aminopropyl)methylamine) have been synthesized by the reactions of Cu(ClO4)2ź6H2O or Cu(NO3)2ź3H2O and ept or medpt, or [Cu(hatce)](ClO4)2ź2H2O and [Cu(hatco)Cl]ClO4źH2O, and K3[Cr(CN)6] or K3[Co(CN)6] in aqueous solution, respectively. All the compounds have been characterized by elemental analyses, IR and UV-Vis spectroscopies and magnetic measurements and the three selected complexes were studied using thermal analysis. The crystal structure of [{Cu(ept)}3{Co(CN)6}2]ź źH2O has been determined by single-crystal X-ray analysis – the studied compound can be for mulated as [{Cu(ept)}6{Co(CN)6}3][Co(CN)6]ź2H2O. The copper atom is five-coordinated by two cyanide-nitrogen and three ept-nitrogen atoms, in a distorted square-pyramidal arrangement. The structure of the other complexes with cyanide bridges between hexacoordinated chromium(III) (S = 3/2) or cobalt(III) (S = 0) and penta- or hexacoordinated copper(II) (S = 1/2) is proposed.

13

Ocena możliwości usuwania chromu(III) z modelowych roztworów ścieków garbarskich w procesie nanofiltracji

Kowalik A., Kluziński W., Gierycz P., Religa P.

Inżynieria i Aparatura Chemiczna

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2009

|

Nr 5

58-59

PL

W pracy przedstawiono wyniki badań uzyskane podczas nanofiltracji modelowych roztworów ścieków garbarskich o stężeniach 500, 1000, 2000 mg Cr3+/L. Badania przeprowadzono w półtechnicznej instalacji membranowej wyposażonej w spiralny moduł nanofiltracyjny. Zbadano wpływ ciśnienia transmembranowego na objętościowy strumień pcrmeatu oraz retencję chromu(III).

EN

The paper presents results obtained during nanofiltration of model tannery wastewaters containing 500, 1000, 2000 mg Cr' /L. Experiments were carried out in a pilot membrane installation equipped with the spiral-wound nanofiltration module. An influence of trans-membrane pressure on permeate flux and retention of chromium(III) was studied.

14

Content of Nitrogen Compounds in Soil Polluted with Chromium(III) and Chromium(VI) after Application of Compost, Zeolite and Calcium Oxide

Wyszkowski M., Radziemska M.

Ecological Chemistry and Engineering. A

|

2009

|

Vol. 16, nr 8

1039-1045

EN

The present study has been undertaken in order to determine the influence of tri- and hexavalent chromium compounds - 25, 50, 100 and 150 mg *kg-1 of soil on the concentration of nitrogen compounds in soil after crop harvest, and the effectiveness of neutralizing substances, such as compost, zeolite and calcium oxide, on alleviating results of chromium pollution. Soil contamination with chromium(III) and chromium(VI) significantly modified the content of nitrogen compounds in soil after plant harvests. Under the influence of trivalent chromium, in a series lacking any neutralising substances, the total nitrogen content decreased while the ammonia nitrogen level rose after plant harvest. Chromium(VI) had a similar influence on N-NH4 . The neutralising substances added to soil, such as compost, zeolite and calcium oxide had a significant effect on the content of total nitrogen in soil. Calcium oxide in the objects polluted with chromium(III) and chromium(VJ) caused a significant decrease in the content of N-total in soil. Compost, zeolite and calcium oxide caused an increase in the average content of N-NO3- in soil, with the effect being stronger in post polluted with chromium(VI) than with chromium(III). As for chromium(VI), the content of N-NO3- was most strongly affected by calcium oxide added as a soil amending substances. All the tested neutralising substances had a weaker influence on the content of N-NH4+ in soil.

PL

Celem przeprowadzonych badań było określenie wpływu wzrastającego zanieczyszczenia związkami chromu(III) i chromu(VI) - 25, 50, 100, 150 mg o kg-1 gleby oraz kompostu, zeolitu i tlenku wapnia na zawartość związków azotowych w glebie po zbiorze jęczmienia jarego i kukurydzy. Zanieczyszczenie chromem(III) i chromem(VI) znacząco modyfikowało zawartość związków azotowych w glebach po zbiorze roślin. Pod wpływem chromu trójwartościowego w serii bez dodatków łagodzących nastąpiło zmniejszenie zawartości N-ogólnego, natomiast zwiększenie stężenia N-amonowego w glebie po zbiorze roślin. Podobny wpływ miał chrom(VI) w przypadku N-NH4+. Zastosowane dodatki neutralizujące w postaci kompostu, zeolitu i tlenku wapnia miały znaczący wpływ na zawartość badanych form azotu w glebie. Tlenek wapnia w obiektach z chromem(III) i chromem(VI) wywołał znaczące zmniejszenie zawartości N-ogólnego w glebie. Kompost, zeolit i tlenek wapnia spowodował zwiększenie średniej zawartości N-NO3- w glebie, przy czym działanie to było większe w wazonach z chromem(VI) niż w obiektach z chromem(III). W przypadku chromu(VI) na zawartość N-NO3- najsilniej wpływał dodatek do gleby tlenku wapnia. Zastosowane substancje najsłabiej działały na zawartość N-NH4+ w glebie.

15

Synthesis, Characterization and Antiferromagnetic Interaction in Oxalato-Bridged Chromium(III)-Chromium(III) Binuclear Complexes

Wang S., Li Y., Yan C.

Polish Journal of Chemistry

|

2006

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Vol. 80, nr 6

865-872

EN

Two new mi-oxalato-bridged binuclear chromium(III) complexes, [Cr2(ox)(salen)(bpy)2]- (NO3)2 (1) and [Cr2 (ox)(salen)(phen)2](NO3)2 (2) [where salen = N,N'-ethylenebis- (salicylideneiminate), ox = oxalato, bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline], have been synthesized by the strategy of 'complex as ligand', and characterized by elemental analyses, molar conductance and magnetic moments of room-temperature measurements, and spectroscopic studies. It is proposed that the two complexes have extended ox-bridged structures consisting of two chromium(III) ions, each in an octahedral environment. The two complexeswere further characterized by variable temperature magnetic susceptibility (4.2~300 K) measurements and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H= - 2JS S 1 2 giving the exchange integrals J = -2.78 cm-1 for (1) and J = -3.85 cm-1 for (2). This result indicates the presence of weak antiferromagnetic interaction between the metal ions within each molecule.

16

Synthesis and Ferromagnetic Interaction in Oxamido-Bridged Copper(II)-Chromium(III) Heterotetranuclear Complexes

Wang S., Li Y., Yan C.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 8

1327-1336

EN

Two new mi-oxamido-bridged copper(II)-chromium(III) heterotetranuclear complexes formulated as [Cu3 (dmoxae)3Cr](ClO4 )3 (1) and [Cu3(dmoxpn)3Cr](ClO4)3 (2), where dmoxae and dmoxpn represent N,N'-bis[2-(dimethylamino)ethyl]oxamido and N,N'-bis[3-(dimethylamino)propyl]oxamido dianions, respectively, have been synthesized and characterized by the elemental analyses, spectroscopic (IR, UV, ESR) studies, magnetic moments (at room-temperature) and by molar conductivity measurements. It is proposed that these complexes have oxamido-bridged structures consisting of three copper( II) ions and a chromium(III) ion, in which the chromium(III) ion has an octahedral environment and the three copper(II) ions have a square-planar environment. The two heterotetranuclear complexes were further characterized by variable-temperature magnetization (3~300 K) measurements and the magnetic data have been used to deduce the indicated heterotetranuclear structure. The results derived from least-squares fit of the experimental data have confirmed that the operation of a ferromagnetic interaction between the adjacent copper(II) and chromium(III) ions occurs through the oxamidobridge within each molecule. On the basis of the spin Hamiltonian operator, H= - 2J(S cu . S cr + S cu2 . S cr + S cu2 . S cr ), the magnetic analyses were carried out for the two copper(II)-chromium(III) heterotetranuclear complexes and the spin-coupling constants (J)were evaluated as +9.28 cm-1 for (1) and+9.63 cm-1 for (2). The influence of the symmetry of the magnetic orbitals on the nature of the magnetic interaction between the paramagnetic centers is preliminary discussed.

17

Wpływ utleniających modyfikacji powierzchni węgla aktywnego na pojemności sorpcyjne w stosunku do Cr(III) i Cr(VI)

Lach J., Biniak S., Walczyk M.

Inżynieria i Ochrona Środowiska

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2006

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T. 9, nr 3

249-259

PL

Wykorzystano utleniony węgiel aktywny WG-12 do usuwania Cr(III) oraz Cr(VI) z wody. Modyfikację tę przeprowadzano w temperaturze 400°C w piecu obrotowym oraz na stanowisku elektrycznego ogrzewania węgla (SEOW). W przypadku węgli modyfikowanych przepływ gazów utleniających nagrzanych do temperatury panującej w piecu obrotowym (dwutlenku węgla, pary wodnej oraz powietrza) prowadzono wraz z nagrzewaniem węgla. W przypadku utleniania węgla z wykorzystaniem SEOW najpierw nagrzewano węgiel w trakcie przewodzenia prądu elektrycznego do temperatury 400°C, a następnie studzono złoże gazami utleniającymi (dwutlenkiem węgla i powietrzem). Otrzymane węgle aktywne charakteryzowały się zwiększoną ilością ugrupowań o charakterze zasadowym. Sumaryczna liczba kwasowych tlenków powierzchniowych znacznie się zwiększyła dla węgla utlenianego w piecu obrotowym przy przepływie powietrza. Na pozostałych węglach nie zmieniła się w istotny sposób liczba tych ugrupowań. Wszystkie modyfikowane węgle zwiększyły pojemności sorpcyjne w stosunku do Cr(III) i Cr(VI). Najlepsze rezultaty usuwania Cr(III) otrzymano na węglu modyfikowanym w piecu obrotowym z udziałem powietrza. Węgiel ten charakteryzował się również największą ilością ugrupowań o charakterze kwasowym oraz zwiększoną liczbą ugrupowań o charakterze zasadowym. Najlepsze rezultaty usuwania Cr(VI) otrzymano na węglu utlenianym parą wodną w piecu obrotowym. Węgiel ten charakteryzował się zwiększoną ilością grup funkcyjnych o charakterze zasadowym oraz najwyższym pH wyciągu wodnego.

EN

There was examined the oxidized activated carbon in regard to Cr(III) and Cr(VI) removing from water. All modified carbons increased the adsorption capacities in relation to Cr(III) and Cr(VI). The modification was carried out at the temperature of 400°C in a rotary furnace and by the electrical heating of carbon bed (SEOW). In the case of modified carbons the flow of oxidizing gases (carbon dioxide, water vapour and air), heated up to the temperature which is in the rotary furnace, were carried out together with the heating of carbon. In the case of carbon oxidation with the usage of SEOW; firstly the carbon was heated during the carrying of electric current up to the temperature of 400°C; then the bed was cooled down by means of oxidizing gases (carbon dioxide and air). The most effective carbon, in the case of removing Cr3+ cation appeared to be WG/400/AIR. The other modified carbons, both from the rotary furnace and from SEOW, have similar, however, higher than initial carbon, abilities of Cr(III) removing. There was also examined the adsorption of hexavalent chromium, in the form of chromate anion. All modified carbons have greater abilities of removing the chromate ion with the exception of WG/400/AIR carbon. While comparing the amount of the removed: Cr(III) and Cr(VI) on initial carbon and modified carbons, there can be observed that hexavalent chromium is removed to a much greater degree. In order to evaluate the chemical character of the surface of the examined activated carbons, there were also examined the amounts of functional groups and there were made the measurements of FTIR spectrum. The increase of number of basic groups was observed. The total number of acidic surface oxides increased, in a significant way, for carbon oxidized in the rotary furnace at the air flow. The number of these units did not change in an essential way on the other carbons. There can be observed no important differences among the examined carbons from the course of the FTIR curves. There were also studied the changes of surface quantity and of porous structure of the analysed activated carbons. There was observed, in most examined carbons, the increase of specific surface quantity and the volume of micropores. The loss of meso- and macropores was noticed.

18

Synthesis and Magnetism of Ferromagnetically Coupled {Cu II 3 Cr III] Heterotetranuclear Complexes with N,N'-Bis(aminoalkyl)oxamidatocopper(II)

Li Y., Yan C., Xu G., Zhang G., Sun W.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 9

1415-1424

EN

The strategy of "complex as ligand" allowed us to synthesize two new _-oxamido- bridged copper(II)-chromium(III) heterotetranuclear complexes formulated as [Cu3(oxae)3Cr](ClO4)3 (1) and [Cu3(oxpn)3Cr](ClO4)3 (2), where oxae and oxpn represent N,N_-bis(2-aminoethyl)oxamido and N,N_-bis(3-aminopropyl)oxamido dianions, respectively. Based on elemental analyses, molar conductivity and magnetic moment (room-temperature) measurements, IR, ESR and electronic spectral studies, these complexes are proposed to have oxamido-bridged structures consisting of three copper(II) ions and a chromium(III) ion, in which the chromium(III) ion has an octahedral environment and the three copper(II) ions have a square-planar environment. The two heterotetranuclear complexes were further characterized by variable-temperature magnetic susceptibility (3~300 K) measurements and the magnetic data have been used to deduce the indicated heterotetranuclear structure. The results derived from least-squares fit of the experimental data have confirmed the ferromagnetic interaction between the adjacent copper(II) and chromium(III) ions through the oxamido-bridge within each molecule. On the basis of the spin Hamiltonian operator, H=-2J(S Cu1 . S Cr+S Cu2 . S Cr + S Cu3 . S cr) , the magnetic analyses were carried out for the two copper(II)-chromium(III) heterotetranuclear complexes and the spin-coupling constants (J) were evaluated as +13.98 cm-1 for (1) and +12.65 cm-1 for (2). The results indicate that the bridging oxamido should be able to transmit ferromagnetic interaction in the strict orthogonality [Cu3 IICrIII] system. The influence of the symmetry of the magnetic orbitals on the nature of the magnetic interaction between the paramagnetic centers is preliminarily discussed.

19

Synthesis of Ferromagnetic Cu3IICrIII-Type Heterotetranuclear Complexesv with Oxalato Bridges

Li Y., Yan C., Guan H.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 1

9-18

EN

Three new _-oxalato-bridgedCu3 IICrIII-type heterotetranuclear complexes have been synthesized and identified as: [Cu3Cr(ox)3(phen)3](ClO4)3 (1), [Cu3Cr(ox)3(Me2phen)3](ClO4)3 (2) and [Cu3Cr(ox)3(NO2phen)3](ClO4)3 (3), where ox represents the oxalato dianions; phen, Me2phen and NO2phen represent 1,10-phenanthroline; 2,9-dimethyl-1,10-phenanthroline or 5-nitro-1,10-phenanthroline respectively. These complexes are the first examples of [Cu3 IICrIII] species bridged by oxalato groups. The three complexes have not yet been isolated in crystalline form suitable for X-ray structure analysis, but based on elemental analyses, molar conductivity and magnetic moment (at room-temperature) measurements, IR, ESR and electronic spectral studies, these complexes are proposed to have oxalato-bridged structure consisting of three copper(II) ions and a chromium(III) ion, in which the chromium(III) ion has an octahedral environment, and the three copper(II) ions have a square-planar environment.Variable temperature magnetic susceptibility (4.2~300 K) measurements and studies of the complexes (1) and (2) revealed the occurrence of an intramolecular ferromagnetic interaction between the copper(II) and chromium(III) ions through the oxalato-bridge within each molecule. The magnetic data have been also used to deduce the indicated _-oxalato-bridged [Cu3 IICrIII] tetranuclear structure. On the basis of the spin Hamiltonian operator,_ _ _ _ _ _ _ H= 2J(S S S S S S Cu1 Cr Cu2 Cr Cu3 Cr Ĺ + Ĺ + Ĺ ), the magnetic analyses were carried out for the two CuII-CrIII heterotetranuclear complexes and the spin-coupling constants (J) were evaluated as +10.97 cm-1 for (1) and +9.28 cm-1 for (2), indicating that the bridging oxalato would be able to transmit ferromagnetic interaction in the strict orthogonality [Cu3 IICrIII] tetranuclear system.

20

Synthesis and Magnetic Characterization of mi-Oxamido-bridged Cu(II)-M(III) (M=Fe and Cr) Heterobinuclear Complexes

Li Y., Yan C. -W., Guan H. -S.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 10

1235-1244

EN

Two new _-oxamido-bridged heterobinuclear complexes have been synthesized and identified as [Cu(dmoxae)Cr(Ph2phen)2](ClO4)3 (1) and [Cu(dmoxae)Fe(Ph2phen)2](ClO4)3 (2), where dmoxae denotes N,N_-bis[2-(dimethylamino)ethyl]oxamido dianion and Ph2phen represents 4,7-diphenyl-1,10-phenanthroline. Based on elemental analyses, IR, ESR and electronic spectra studies, and molar conductivity measurements, the complexes are proposed to have an extended oxamido-bridged structure consisting of planar copper(II) and octahedral chromium(III) or iron(III) ions. The two heterobinuclear complexes were further characterized by variable-temperature magnetic susceptibility (4.2~300 K) measurements and the magnetic data have been also used to deduce the indicated heterobinuclear structure. The results derived from least-squares fit of the experimental data have confirmed that the adjacent copper(II) and chromium(III) ions through the oxamido-bridge in complex (1) are ferromagnetically coupled with the exchange integral J(Cu-Cr) = +13.6 cm-1, while an intramolecular antiferromagnetic coupling is detected between the copper(II) and iron(III) ions through the oxamido-bridge in complex (2) with the exchange integral J(Cu-Fe) = -17.5 cm-1, on the basis of the spin Hamiltonian operator, _ _ _ H JS S Cu M = Ĺ 2 (M = Cr3+ and Fe3+). The influence of electronic-structural variation of the metal ions on the nature of spin-exchange interaction between the paramagnetic centers is also discussed.