Osmium(III) Halide Complexes with para-and meta-Substituted Benzeneseleninato Ligands

1985 ◽  
Vol 38 (11) ◽  
pp. 1675 ◽  
Author(s):  
G Graziosi ◽  
C Preti ◽  
G Tosi ◽  
P Zannini
Keyword(s):  
Field Theory ◽  
Molar Ratio ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
Crystal Field Theory ◽  
Halide Complexes ◽  
Thermogravimetric Studies ◽  
Q Values ◽  
Metal Ligand ◽  
Octahedral Configuration

New complexes of osmium(III) with para - and meta-substituted benzeneseleninic acids of the type XC6H4SeO2H (X = H, p- Cl , m- Cl , p-Br, m-Br, p-Me) are reported. The compounds, of the type Os(XC6H4SeO2)3, Os(XC6H4SeO2)2Y, Os(XC6H4SeO2)Y2 and Os2(XC6H4SeO2)3Y3 (Y = Cl , Br), have been studied through spectroscopic techniques ( i.r ., far- i.r .and electronic spectra), magnetic susceptibility measurements, thermogravimetric studies and conductivity measurements. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal-field theory; the nephelauxetic parameter is indicative of an appreciable metal- ligand covalency. It is worth noting that among the present complexes the highest q values are related to the Os(XC6H4SeO2)3 derivatives in which OsO6 chromophores are present; the Dq values decrease on passing to the 1 : 2, 1 : 1.5 and 1 : 1 metal/ ligand molar ratio complexes according to the presence of chlorine- and bromine-containing chromophores . The i.r . data point to a seleninato -O,O′ coordination for all the complexes; in particular, the presence of three SeO bands with the irreducible representation A2 + 2E in the i.r . spectra of the tris derivatives suggests an octahedral configuration with D3 symmetry. All the halo complexes are polymeric octahedral with bridging halide atoms. The magnetic moment values lie in the expected range for the trisbenzeneseleninato derivatives, and they decrease on passing to the halo complexes.

Chromium(III), manganese(II) and iron(III) O,O'-bonded complexes of the para- and meta-substituted benzeneseleninic acids

1980 ◽  
Vol 33 (6) ◽  
pp. 1203 ◽  
Author(s):  
C Preti ◽  
G Tosi
Keyword(s):  
Field Theory ◽  
Spectral Data ◽  
Crystal Field ◽  
Electronic Spectra ◽  
Conductivity Measurements ◽  
Crystal Field Theory ◽  
Metal Ligand ◽  
Bonded Complexes

A number of complexes of chromium(III), manganese(II) and iron(III) with para- and meta-substituted benzeneseleninic acids, XC6H4SeO2H (X = H, p-Cl, m-Cl, p-Br, m-Br, p-Me), are reported. The newly prepared compounds are characterized on the basis of near-i.r. and far-i.r. spectroscopy, electronic spectra and conductivity measurements, as well as by magnetochemical evidence. The wavelengths of the principal absorption peaks have been accounted for quantitatively in terms of the crystal field theory for chromium(III) and manganese(II) derivatives. The nephelauxetic parameters are all indicative of an appreciable metal-ligand covalency. The i.r. spectral data suggest that the ligands act as bidentate in seleninato-O,O' complexes and we can propose octahedral geometries with D3 symmetry for the chromium(III) and iron(III) derivatives and octahedral geometries, distorted towards D4h, for the manganese(II) complexes, in which the water has been shown to be coordinated to the metal.

The coordinating ability of the antibiotic cycloserine towards transition metal halides

1980 ◽  
Vol 33 (1) ◽  
pp. 57 ◽  
Author(s):  
C Preti ◽  
G Tosi
Keyword(s):  
Field Theory ◽  
Magnetic Properties ◽  
Ring Opening ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Manganese Complexes ◽  
Chemical Analyses ◽  
Conductivity Measurements ◽  
Crystal Field Theory ◽  
Experimental Conditions

A series of cycloserine complexes of chromium(III), manganese(II), rhodium(III) and iridium(III) halides has been prepared and characterized by chemical analyses, conductivity measurements, room temperature magnetic moment studies, electronic, i.r. and far-i.r. spectra and isotope exchange (deuteration) experiments. From the magnetic properties it was concluded that the above ligand forms high- spin complexes with chromium(III) and manganese(II) and low-spin complexes with rhodium(III) and iridium(III). The position and multiplicity of the metal-halogen stretching modes in the far-i.r. region have been extensively investigated, the results being particularly useful in distinguishing between the mer and fac isomers in the ML3X3-type octahedral complexes. The ligand behaves as monodentate O-bonded. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal field theory and the various parameters have been calculated. The calculated Dq parameters are in accord with the presence of CrO6, CrN3X3, RhO3X3 and IrO3X3 chromophores according to the infrared results. The values of B and C obtained for the manganese complexes are significantly lower than the corresponding values for the free gaseous ion. Under our experimental conditions no metal-induced ring opening of the ligand was observed.

Coordination compounds of manganese(II) with Tetrahydro-1,4-thiazin-3-one and Thiazolidine-2-thione

1976 ◽  
Vol 29 (3) ◽  
pp. 543 ◽  
Author(s):  
C Preti ◽  
G Tosi
Keyword(s):  
Field Theory ◽  
Infrared Spectroscopy ◽  
Oxygen Atom ◽  
Coordination Compounds ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Crystal Field Theory ◽  
Characterization Studies ◽  
Metal Ligand

Synthetic and characterization studies of manganese(11) complexes with tetrahydro-l,4-thiazin-3-one (tht) and thiazolidine-2-thione (ttz) are reported. The methods used for the characterization of the compounds include elementary analyses, molar conductances, magnetic moments and electronic and infrared spectroscopy. Assignments for the metal-ligand modes have also been made; the tht derivatives are coordinated through the oxygen atom, while the ttz derivatives are nitrogen-bonded in all the complexes. By use of infrared spectroscopy it has been possible distinguish whether or not the polyanions present in these derivatives are coordinated to the metal ion or are present as free ions.The wavelengths of the principal absorption peaks have been accounted for quantitatively in terms of the crystal field theory. The values of B and C obtained are significantly lower than the corresponding value for the free gaseous ion.

A Solvent-Dependent and Electrochemically Controlled Self-Assembling/Disassembling System

2003 ◽  
Vol 68 (9) ◽  
pp. 1647-1662 ◽  
Author(s):  
Valeria Amendola ◽  
Massimo Boiocchi ◽  
Yuri Diaz Fernandez ◽  
Carlo Mangano ◽  
Piersandro Pallavicini
Keyword(s):  
Equilibrium Mixture ◽  
Bidentate Ligand ◽  
Molecular Structures ◽  
The Self ◽  
Molar Ratio ◽  
Crystal And Molecular Structures ◽  
Self Assembling ◽  
Irreversible Oxidation ◽  
Irreversible Reduction ◽  
Metal Ligand

The bis-bidentate ligand R,S-1,2-diphenyl-N,N'-bis(2-quinolinemethylidene)ethane-1,2-diamine (ligand 4), containing two (iminomethyl)quinoline moieties separated by a cis-1,2-diphenylethylene spacer, forms stable complexes with both CuI and CuII. With CuII, the monomeric 1:1 complex [CuII(4)]2+ is obtained both in CH3CN and CH2Cl2. With CuI and overall 1:1 metal/ligand molar ratio, an equilibrium mixture is obtained in CH3CN, consisting of [CuI(4)2]+, [CuI2(4)2]2+ and [CuI2(4)(CH3CN)4]2+. The preponderant species is the two-metal one-ligand "open" complex [CuI2(4)(CH3CN)4]2+, in which each Cu+ cation is coordinated in a tetrahedral fashion by one (iminomethyl)quinoline unit and by two CH3CN molecules. Precipitation from the equilibrium mixture yields only crystals of [CuI2(4)(CH3CN)4](ClO4)2·2CH3CN, whose crystal and molecular structures have been determined. On the other hand, in the poorly coordinating CH2Cl2 solvent, only the dimeric helical [CuI2(4)2]2+ complex is obtained, when the overall metal/ligand 1:1 molar ratio is chosen. Addition of large quantities of acetonitrile to solutions of [CuI2(4)2]2+ in dichlorometane results in the formation of [CuI2(4)(CH3CN)4]2+, i.e. in the solvent-driven disassembling of the CuI helicate. While electrochemistry in CH3CN is poorly defined due to the presence of more than one CuI species, cyclic voltammetry experiments carried out in CH2Cl2 revealed a well defined behavior, with irreversible oxidation of [CuI2(4)2]2+ and irreversible reduction of [CuII(4)]2+ taking place at separate potentials (∆E ≈ 700 mV). Irreversibility and separation of the redox events are due to the self-assembling and disassembling processes following the reduction and oxidation, respectively.

scholarly journals Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with N2O2 Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lakhdar Sibous ◽  
Embarek Bentouhami ◽  
Mustayeen Ahmed Khan
Keyword(s):  
Schiff Base ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Electrochemical Behaviour ◽  
Absolute Ethanol ◽  
Molar Ratio ◽  
H Nmr ◽  
Chelating Ligand ◽  
Metal Ligand

4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate CoII and NiII chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated.

Metal Isotope Effect on Metal-Ligand Vibrations. IX. Far Infrared Spectra of Octahedral Nickel Halide Complexes of Pyridine and γ-Picoline

1973 ◽  
Vol 27 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Y. Saito ◽  
C. W. Schläpfer ◽  
M. Cordes ◽  
K. Nakamoto
Keyword(s):  
Isotope Effect ◽  
Infrared Spectra ◽  
Far Infrared ◽  
Isotopic Shifts ◽  
Halide Complexes ◽  
Far Infrared Spectra ◽  
Metal Ligand

The far infrared spectra of Ni (pyridine)4X2 and Ni(γ-picoline)4X2 (X = CI, Br and I) have been measured. The Ni-X and Ni-N stretching bands have been assigned based on isotopic shifts due to the 58Ni-62Ni, pyridine-pyridine-d5, and Cl-37Cl substitutions.

scholarly journals Crystal Field Theory of Magnetic Behaviour of Er2(SO4)3·8H2O

1996 ◽  
Vol 89 (5-6) ◽  
pp. 649-655
Author(s):  
R. Gupta ◽  
U.S. Ghosh ◽  
C. Basu
Keyword(s):  
Field Theory ◽  
Crystal Field ◽  
Magnetic Behaviour ◽  
Crystal Field Theory

scholarly journals Optical absorption of LiNaGe4O9:Mn crystal

2021 ◽  
Vol 29 (1) ◽  
pp. 69-72
Author(s):  
A. Yu. Osetsky ◽  
T. V. Panchenko ◽  
M. D. Volnianskii ◽  
M. P. Trubitsyn
Keyword(s):  
Field Theory ◽  
Optical Absorption ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Optical Absorption Spectra ◽  
Crystal Field Theory ◽  
Absorption Bands ◽  
Additional Absorption ◽  
Impurity Ions ◽  
Semi Empirical

The paper reports the results of optical absorption spectra studying in LiNaGe4O9 crystal doped with Mn. It is shown that Mn impurity causes the appearance of the additional absorption bands. The intensities of these bands change in different ways in the range of the ferroelectric phase transition. Semi-empirical version of the crystal field theory is used to discuss localization and charge state of Mn impurity ions in the LiNaGe4O9 structure.

scholarly journals Advances of crystal field theory and exchange charge model

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
M.G. Brik ◽  
◽  
N.M. Avram ◽  
C.N. Avram ◽  
◽  
...  
Keyword(s):  
Field Theory ◽  
Crystal Field ◽  
Crystal Field Theory ◽  
Charge Model ◽  
Exchange Charge Model
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