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Izomery porfiryny : podobieństwa i różnice

Waluk Jacek

Wiadomości Chemiczne

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2021

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[Z] 75, 5-6

631--652

EN

Porphyrins, “pigments of life”, are extremely popular objects of fundamental research and as candidates for diverse applications. The prerequisite for a successful application is the understanding of the electronic structure. For that purpose, it is instructive to compare the properties of porphyrin with those of its isomers. To date, six such isomers have been synthesized. In this work, we compare the characteristics of all “nitrogen-in”, N-confused- and neo-confused porphyrin isomers, including three structures that have not yet been obtained. We discuss the electronic spectra, intramolecular hydrogen bonding, and tautomerism. Analysis of the energy pattern of frontier orbitals allows predicting the redox properties, as well as the pattern of electronic absorption and magnetic circular dichroism (MCD) spectra. In turn, the geometry of the inner cavity is the factor that determines the strength of hydrogen bonds and, in consequence, the kinetics of tautomerization.

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Synthesis and Characterization of First Row Transition Metal Complexes of a Schiff Base Hydrazone Containing Quinoxaline Moiety

Anantha Lakshmi P. V., Shyamala B. S., Jayatyaga Raju V.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1555-1563

EN

A series of new chromium(III), manganese(II), iron(III), cobalt(II), nickel(II) and copper(II) complexes of the Schiff base hydrazone (HDHAHQO), synthesized from 3-hydrazinoquin oxaline-2-one (HQO) and dehydroacetic acid (DHA) were prepared and characterized. The Schiff base exhibits biambidenticity. It be haves as a monobasic tridentate ONN donor in iron(III) and copper(II) complexes and ONO donor in chromium(III), manganese(II), cobalt(II) and nickel(II) complexes. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, thermal, infrared, electronic spectra, magnetic susceptibility and conductivity measurements. An octahedral geometry was suggested for all the complexes. The Schiff base ligand, HDHAHQO, and its complexes were tested against one strain Gram+ve bacteria (Staphylococcus aureus), Gram-ve bacteria (Escherichia coli). The prepared metal complexes exhibited higher antibacterial activities than the parent ligand.

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Quantum Chemistry Studies on Bis(p-aminobenzoato)–lead(II) Complex [Pb(C6H4NH2COO)2]

Zhao P., Xu J., Li R., Zhang W., Cai Z.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 1

85-93

EN

The title complex, bis(p-aminobenzoato)–lead(II) [Pb(C6H4NH2COO)2], has been optimized at B3LYP/LANL2DZ level of theory and the calculated results show that the lead(II) ion adopts a four-coordinate geometry. The analyses of NPA and Mulliken atomic charge distributions indicate that during the process of the formation of this compound, both aminobenzoato ligands transfer their negative charges to the lead(II) ion. The lead atom and oxygen atoms form covalent bonds by using their 6p and 2p orbitals, respectively. The calculations of electronic spectra of the title complex show that there exist four absorption bands and the electronic transitions are mainly derived from the contributions ofboth an intraligand* transition and ligand-to-metal charge transfer (LMCT) transitions. The thermodynamic properties of the studied compound at different temperatures have been calculated and the corresponding relations between the properties and temperatures have also been obtained. The calculation of the second order optical nonlinearity has been carried out, and the molecular hyperpolarizability of the title complex is 7.61379x10–30 esu.

4

Experimental and Density Functional Studies on Two Substituted 1H-Benzimidazoles

Zhao P., Yu H., Jian F., Wang X.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1511-1519

EN

Two substituted 1H-benzimidazoles, 2-(4-chlorophenyl)-1H-benzimidazole and 1-(2- chlorobenzyl)-2-(2-chlorophenyl)-1H-benzimidazole, have been synthesized and characterized by elemental analysis, IR and UV-Vis spectra. An extended MO calculations using density functional theory (DFT) at B3LYP/6-311G** level have been carried out on the two compounds. Comparison of the experiments with the calculated results suggests that the optimized geometries can well reproduce the molecular structures. Atomic charge distributions show that both of the title compounds are potential ligands to coordinate with metallic ions. Natural population analyses indicate that the electronic transitions corresponding to electronic spectra are mainly derived from the contribution of bands pi--pi*. Thermodynamic properties of the two title compounds at different temperatures have also been calculated on the basis of vibration analyses.

5

Hydrazinium Complexes of Lanthanide and Transition Metal Squarates

Vairam S., Govindarajan S.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 10

1601-1614

EN

Reaction of the ligands, squaric acid and hydrazine with Ln(NO3)3 where Ln(III) = La, Pr, Nd, Sm, Gd and Ce results in the formation of the complexes of the formula, N2H5[Ln(C4O4)2]xH2O where x = 3, 5 and 6 and their reaction with transition metal nitrates, M(NO3)2xH2O, where M(II) = Co, Ni, Cu, Zn and Cd in aqueous solution yields the squarates of the types, [(N2H5)3M(C4O4)2.5]2H2O where M(II) = Co, Ni and Cd; [(N2H5)2Zn(C4O4)2]2H2O and [(N2H5)Cu(C4O4)1.5 ]. Neutralization of the acid with hydrazine hydrate gives dihydrazinium squarate hydrate, (N2H5)2(C4O4)H2O. All the above complexes, except Cd, are sparingly soluble in water and are characterized by IR, UV-visible, ESR and thermoanalytical methods. The squarates appear to behave as bis-monodentate and tetrakis-monodentate bridged ligands in transition metal and lanthanide complexes respectively. Hydrazinium cation acts as a coordinating ligand in transition metal complexes whereas it is a charge compensating species in lanthanide squarates. This fact is revealed from their IR spectra by displayingN-N frequency at 1000 cm–1 in the former case and at 950 cm–1 in the latter. Squarate compounds exhibit very high exothermic decomposition. Hydrazinium lanthanide squarates show weight losses due to dehydration and dehydrazination from 68 graduate C to 258 graduate C and a strong exothermic decomposition between 176 graduate C and 700 graduate C leading to the formation of metal oxides/oxy carbonates as the end products possibly via H[Ln(C4O4)2] intermediate. Transitionmetal compounds loose water and hydrazine in the range of 50–275 graduate C, and then undergo strong exothermic decomposition above 200 graduate C with no stable intermediate formation. Simple hydrazinium salt decomposes completely exothermally at 179 graduate C. The electronic spectra indicate the coordination number (CN) and geometry; CN 8 with square anti-prism for lanthanides and CN 6 with octahedral arrangement for transition metals. The geometry of the complexes is substantiated by their electronic spectra, magnetic

6

Ligand-Field Analysis of Low-Spin N,N'-Propylenebis(naphthyldiiminate)nickel(II) in Ethanol Solution

Kurzak K., Gonciarz A., Kuźniarska-Biernacka I.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

47-56

EN

Titled complex denoted as [Ni(nappn)]ź0.5H2O, where H2nappn is tetradentate Schiff base: 1,3-bis(naphthylideneimine)propane, has been characterized by elemental analysis, molar conductivity, ultraviolet (UV) and visible (Vis) spectroscopy. The known X-ray structure of this complex shows that Ni atom adopts square-planar coordination. Combined multi-technique experiments have been applied to establish the structure of complex in solution. The molar conductivity value indicates non-electrolytic properties of solution studied. The spectroscopic measurements were used to study the coordination properties of donor-atoms and their bonding abilities. All the experimental transition energies are derived from Gaussian analysis of the solution spectrum. The d-d transition energies were used to derive the angular overlap model (AOM) and crystal-field model (CFM) parameters for the studied complex inD4h symmetry. The first full ligand-field interpretation of the low-spin Schiff base nickel(II) complex in solution has been presented.

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Experimental Studies on Isonicotinato Zinc(II) Complex [Zn(C6H4NO2)2(H2O)4] and Density Functional Calculations

Zhao P., Jian F., Li C.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 6

1041-1046

EN

Isonicotinato zinc(II) complex [Zn(C6H4NO2)2(H2O)4] has been synthesized by hydrothermal method and characterized by elemental analysis, electronic-spectra and thermogravimetric analysis. Density functional theory (DFT) method calculations of the structure, atomic charges distribution, electronic spectra, natural population analysis and the thermodynamic properties at different temperatures have been performed. The calculated results show the electronic transitions are mainly derived from the contribution of pi--pi* bands and the decomposition of the title compound should firstly occur at the bond of Zn-O, then at the bond of Zn-N, which agrees very well with the experimental data.

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Spectrochemical Properties of Noncubic Transition Metal complexes in Solutions. XVI. Angular Overlap Treatments of cis-Bis(2,2'-bipyridyl)oxalatechromium(III) Iodide in Aqueous Solution

Kurzak K., Biernacki K.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 5

673-679

EN

The electronic absorption spectrum of cis-[Cr(ox)(bpy)2]I (bpy = 2,2_-bipyridyl; ox = oxalate ion) of aqueous (H2O) solution, has been measured at room temperature and interpreted using the angular overlap model (AOM), and assuming C2v as the effective symmetry. All the experimental transitions are derived from Gaussian analysis of the solution spectrum. The calculations of the ligand field parameters take into account all the transitions, which are required from the ligand field theory (except those energetically higher than the range of the measured spectrum). The coordination

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Spectrochemical properties of Noncubic transition Metal Complexes in Solutions. XVII. Angular Overlap Treatment of cis-Bis(2,2'-bipyridyl)malonatechromium(III) Iodide in Aqueous Solution

Kurzak K., Biernacki K.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 5

681-686

EN

Amixed ligands chromium(III) complex with bidentate ligands: 2,2_-bipyridyl (bpy) and malonic acid deprotonated (mal-, malonate ion), has been synthesized, investigated and characterized structurally and spectroscopically. Electronic spectra of this complex were recorded in an aqueous solution at room temperature. The 'poor' experimental contours were resolved into the component bands by Gaussian analysis. The spectra were interpreted using C2v symmetry. The resolved spectra have been treated using an angular overlap model (AOM). The effect of _- and _-bonding of the bidentate ligands upon the chromium(III) ion in aqueous solution was described and discussed.

10

Synthesis and Characterization of New Thiocyanato Bridged Complexes with the General Formula [MLn}3[Cr(NCS)6]2.mH2O, where M=Cu(II), Ni(II), Co(II); L=Various Substituted Imidazoles

Wrzeszcz G., Dobrzańska L., Grodzicki A., Rozpłoch F.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 2

147-156

EN

New thiocyanato bridged complexes of the type [CuL4]3[Cr(NCS)6]2_mH2O [L = 1-methylimidazole (1-Meim), 2-methylimidazole (2-Meim), 1,2-dimethylimidazole (1,2- Me2im)] and [M(1-Meim)6]n[{M(1-Meim)4Cr(NCS)6}2n]_mH2O (M = Ni(II), Co(II) were prepared by the reaction of [Cr(NCS)6]3- with the appropriate [MLn]2+ complex in an aqueous solution and characterized by elemental and thermal analysis, IR, UV-VIS, EPR and temperature variable magnetic susceptibility. The presence of NCS bridges between M(II)-Cr(III) centres is evident from IR spectra. The electronic spectra correlate with proposal of different composition of Cu3Cr2 and M3Cr2(M = Ni, Co) systems. The parameters determined from temperature dependence on magnetic susceptibility (80-300 K) indicate weak or negligible antiferromagnetic interaction for obtained Cu(II)-Cr(III), Ni(II)-Cr(III) and Co(II)-Cr(III) systems. Thermal decomposition after dehydration is multistage and yields CuO + CuCrO2 and MIIO+MIICr2O4 as final products, respectively.

11

Spectroscopic, Magnetic and Thermal Properties of New Thiocyanato Bridged Complexes of the Type [M(diamine)2]3[Cr(NCS)6]2.nH2O4, where M=Cu(II), Ni(II)

Wrzeszcz G., Dobrzańska L.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 10

1245-1254

EN

Heteropolynuclear complexes of the type [M(diamine)2]3[Cr(NCS)6]2_nH2O, where diamine = N-methylethylenediamine (N-Me-en), 1,2-diaminopropane (pn); M = Ni(II), Cu(II) have been prepared by reacting [Cr(NCS)6]3- with the corresponding cationic [M(diamine)2]2+ complex in an aqueous solution. They have been characterized by elemental analysis, IR, UV-VIS, EPR, variable temperature magnetic susceptibility and thermal analysis. Spectroscopic studies reveal thiocyanato bridges between M(II)-Cr(III) centres. The parameters determined from temperature dependence on magnetic susceptibility (80-300 K) indicate moderate antiferromagnetic interactions for Ni(II)-Cr(III) and negligibly small or very weak ones for Cu(II)-Cr(III) systems. Magnetic studies suggest also presence of diamagnetic Ni(II) ions in the structure of Ni(II)-pn-Cr(III) complex. Thermal analysis shows higher thermal stability of Ni(II)-Cr(III) than Cu(II)-Cr(III) compounds. The process of thermal decomposition after dehydration is multistage and yields NiO + NiCr2O4and CuO + CuCrO2 as final products, respectively.

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Spectrochemical Properties of Noncubic Transition Metal Complexes in Solutions. XIII. Angular Overlap Treatment of Diaquabis(salicylideneaminothiazole)cobalt(II)

Kuźniarska-Biernacka I., Kurzak K.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 1

13-19

EN

Mixed ligand cobalt(II) complex with monodentate (water) and bidentate (Schiff base: salicylidene-2-aminothiazole) ligands has been characterized by elemental analyses, molar conductivities, ultraviolet (UV) and visible (VIS) spectroscopy. The electronic spectra of solids as well as solutions exhibit pseudo-octahedral coordination geometry for the cobalt centre. The molar conductivities indicate their non-electrolytic properties in solvents studied. Combined multi-technique experiments have been used to postulate theC2h geometry for the species in solutions and to determine the coordination properties of ligators and their bonding abilities (ligand-field parameters).

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One-, Two- and Non-Coordinated Cr02- 4 Entity in the Nickel(II) Complexes. Structural and Spectroscopic Investigation

Pietraszko A., Bronowska W., Wojciechowska A., Staszak Z., Cieślak-Golonka M.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 2-3

309-324

EN

A systematic investigation of the chromate ion in [Ni(II)-(2,2_-bpy)-CrO4 2_ ] systems has been carried out. The effect of the Ni(II) ion and the organic ligand on the mode of the chromate position in the [Ni(bpy)3]CrO4_7.5H2O(1), [Ni(bpy)2(OCrO3)(H2O)]_5H2O(2) and catena-(ž-CrO4-O,O_)[Ni(bpy)(H2O)2]_2H2O (3) complexes has been shown. [Ni(bpy)3]CrO4_7.5H2O crystals (1) have a monoclinic symmetry with space group C2/c and 8 chemical units, forming a unit cell with a = 13.641(3) A, b = 22.939(5) A, c = 23.351(5) A and _ = 104.69(3) deg, whereas the [Ni(bpy)2(OCrO3)(H2O)]_5H2O crystals (2) have a monoclinic symmetry with space group P21/c and 4 chemical units per unit cell with a = 10.854(2) A, b = 22.665(5) A, c = 10.623(2) A and _ = 108.93(3) deg at room temperature. The chromate ion in 1 is not coordinated to the nickel(II) ion. The geometry around the Cr(VI) atom is pseudotetrahedral. Untypical for the chromate ion monodentate coordination has been found in the complex [Ni(bpy)2(OCrO3)(H2O)]_5H2O. The chromate position has been also elucidated from the digitally resolved IR spectra. The coordination of the chromate ion in 2 and 3 was also observed for the single crystal at 4K, in reflectance and solution electronic spectra through the appearance of a new transition at ca. 15000 cm-1. The full characterization of the chromophores present in the complexes: NiN6, NiN4O2, NiN2O4 and NiO6 have been obtained on the basis of the detailed analysis of the electronic spectra at 4K(Gaussian deconvolution followed by digital filtration).

14

Angular Overlap Treatment of cis-Dichlorobis(1,10-phenanthroline)chromium(III) Chloride Dihydrate in Aqueous Solution

Kurzak K., Biernacki K.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

503-509

EN

Low-symmetry mixed-ligands cis-[CrCl2(phen)2]Cl complex (phen = 1,10-phenanthroline) has been characterized spectroscopically. Electronic spectrum of aqueous solution of this complex has been measured at room temperature and interpreted using the angular overlap model (AOM), and assuming C2v symmetry. All the experimental transition energies are derived from Gaussian analysis of the solution spectrum. The calculations of the ligand-field parameters take into account all the transitions, which are required in the ligand-field theory (except those energetically higher than the range of the measured spectrum).

15

Rare earths complexes in sol gel glasses

Reisfeld R.

Materials Science

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2002

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Vol. 20, No. 2

5-18

EN

The origin of the spectra of rare earth ions arising from f->f and f->d transitions are surveyed. The parity forbidden luminescence of lanthanide ions can be strongly intensified by excitation via molecules characterized by high transition probabilities. Such behavior opens a route for creation of a class of new sophisticated materials. Luminescent materials based on heteroaromatic lanthanide cryptates are attractive as labels for advanced time-resolved fluoroimmunoassays, and molecular markers, their potential use is also conceivable in the field of luminescent displays, molecular photonics and highly luminescent materials in hybrid organic/inorganic glasses. The recent findings of lanthanide complexes trapped in sol-gel inorganic glasses based on silica and zirconia networks are discussed and the theoretical basis of their spectroscopy presented.

16

Copper(II) Pyridine-2,6-dicarboxylates. Coordination and Distortion Isomers of [Cu(pydca)(H2O)2]

Koman M., Moncol J., Hudecová D., Dudová B., Melnik M., Korabik M., Mroziński J.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 7

957-964

EN

Copper(II) pyridine-2,6-dicarboxylate dihydrate and its ronicol (ron), nicotinamide (nia) and caffeine (caf) complexes were prepared and their spectral, magnetic as well as their bio-activites were studied. X-ray analysis of [Cu(pydca)(H2O)2] (pydca = pyridine- 2,6-dicarboxylate) shows, that the complex exists in two isomeric forms: monoclinic and triclinic and it is an example of the coordination isomerism. Triclinic forms also exists in two isomeric forms, differing mostly by degree of distortion and being an example of the distortion isomerism. On the basis of spectral and magnetic properties for Cu(pydca)L (L = ron, nia or caf) a square-pyramidal coordination of the copper(II) ion can be proposed. Highest bio-activity shows [Cu(pydca)(H2O)2].

17

Synthesis and Characterization of Thiocyanato-Bridged Heteropolynuclear Chromium(III)-Copper(II) Complexes

Dobrzańska L., Wrzeszcz G., Grodzicki A., Rozpłoch F.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 2

199-206

EN

Heteropolynuclear thiocyanate-bridged complexes were prepared in the reactions of aqueous solutions of K3[Cr(NCS)6] with copper(II) complexes of the type [CuX4]2+, where X=imidazole (imH), 4-methylimidazole (4-MeimH) and 2X= ethylenediamine (en). Solid products were formulated as (Cu(imH)4)3(Cr(NCS)6)2 *2H2O, (Cu(4-MeimH)4)3(Cr(NCS)6)2 *3H2O and (Cu(en)2)3(Cr(NCS)6)2 *2H2O on the basis of elemental analysis and spectral data (IR,UV-VIS). EPR spectra, variable temperature magnetic susceptibility and thermal properties in air were investigated, indicating that all complexes are polynuclear with thiocyanate bridges, exhibiting Curie-Weiss behavior between 80-300 K. Thermal decomposition is multistage and yields CuO and CuCrO2 as final products.

18

Spectrochemical Properties of Noncubic Transition Metal Complexes in Solution : XI. Angular Overlap Studies of Bis(oxalato)- and Bis(malonato)diaquachromate(III) Complexes in Aqueous Solution

Kurzak K.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 3

331-347

EN

Mixed ligands chromium(III) complexes with monodentate(water) and bidentate ligands: oxalic acid deprotonated or malonic acid have been synthesized, investigated and characterized structurally and spectroscopically. Their geometrical isomers have been studied spectrophotometrically in aqueous solution. The "poor" experimental contours were resolved into the component bands by Gaussian analysis.The effect of different bonding of the bidentate ligands upon the chromium(III) ion in aqueous solution was described and discussed.

19

New Coordination Compounds of Copper(II) with Guanidinopyrimidines in N,N-Dimethylformamide

Zawadzki H.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 7

935-944

EN

Several guanidinopyrimidine copper(II) complexes have been prepared in dimethylformamide (DMF) and characterized by elemental analysis, electronic, EPR and vibrational spectra and also by magnetic susceptibility measurements. The structure of the nearest environment of the central ion has been determined.

20

Spectral and thermal properties of copper(II) complexes with methyl-3-pyridyl carbamate

Mojumdar S., Melnik M., Valko M.

Polish Journal of Chemistry

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1999

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vol. 73 nr 3

457-463

EN

Thermogravimetry (TG), differential thermal analysis (DTA), infrared (IR), electronic, EPR spectra and other analytical methods have been applied to the investigation of the thermal behaviour and structure of the compounds [Cu(ac)2(mpc)]2×2CH3OH (I), Cu(Clac02(mpc) (II), Cu(Cl2ac)2(mpc)2 (III) and Cu(Cl3ac)2(mpc)2 (IV) (where ac = CHCOO-, Clac = ClCH2COO-, Cl2ac = Cl2CHCOO-, Cl3ac = Cl3CCOO- and mpc = methyl-3-pyridyl carbamate). The solid phase intermediate and resultant products of thermolysis had been identified. The possible scheme of decomposition of the complexes is suggested with as a final product, CuO. IR data suggest a unidentate coordination of carboxylate to copper(II). Methyl-3-pyridyl carbamate was coordinated through nitrogen atom of its heterocyclic ring in complexes I-IV. EPR spectra suggest a diametric structure of complex I and manometric structure of complexes II-IV.