ABSTRACT
Novel supramolecular rare earth polymeric hydrazone complexes of 5-sulphadiazineazo-3-phenyl-2-thiaxo-4-thiazolidinone (HL) of the composition [(Ln)(2)(HL)(3)(NO(3))(6)](n) (where Ln = La(1), Y(2), Pr(3), Nd(4), Sm(5), Gd(6) and Ho(7)) have been prepared and characterized on the basis of their chemical analyses, magnetic measurements, conductance, visible and IR spectral data. Composition, conductance and IR spectral data of complexes show that all these act as a tetradentate ligand. Electronic spectra indicate weak covalent character in the metal-ligand bond. The spectra of Nd(3+) and Ho(3+) show characteristic f-f transitions and the metal-ligand covalency in % has been evaluated. The spectral properties of the above polymeric complexes are also discussed.
Subject(s)
Hydrazones/chemistry , Metals, Rare Earth/chemistry , Polymers/chemistry , Rhodanine/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , StereoisomerismABSTRACT
Several dioxouranium(VI) heterochelates with tetradentate monobasic hydrazone compounds (HL(n)) have been synthesized. The heterochelates of the type [(UO2)2(HL(n))(L(n))2(OAc)2(OH2)2]n have been characterized on the basis of elemental analyses, IR and electronic spectra, conductance and magnetic susceptibility measurements. The complexes are polymeric, non-electrolytes, diamagnetic and eight-coordinated. Wilson, G.F. matrix method, Badger's formula, Jones and El-Sonbati equations were used to determine the stretching and interaction force constants from which the U-O bond distances were calculated. The bond distances of these complexes were also investigated.
Subject(s)
Hydrazones/chemistry , Nitrogen/chemistry , Spectrophotometry, Infrared/methods , Electrolytes/chemistry , Electrons , Heterocyclic Compounds , Ions , Macrocyclic Compounds , Magnetic Resonance Spectroscopy , Magnetics , Models, Chemical , Molecular Conformation , Polymers/chemistry , Spectrophotometry , Uranium/chemistryABSTRACT
Proton-ligand dissociation constant of 5-(p-aminophenylazo)-8-hydroxyquinoline (HL) and metal-ligand stability constants of their complexes with bivalent (Mn2+, Co2+, Ni2+ and Cu2+) metal ions have been determined potentiometrically in 0.1 M KCl and 30% (v/v) dimethyl formamide (DMF)-water mixture. The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied and the corresponding thermodynamic parameters (delta G, delta H and delta S) were derived and discussed. The dissociation process is nonspontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable.
Subject(s)
Azo Compounds/chemistry , Hydroxyquinolines/chemistry , Metals/chemistry , Algorithms , Indicators and Reagents , Ligands , Potentiometry , Protons , Temperature , ThermodynamicsABSTRACT
Mono, bis and tris complexes of rhodium(III) oxine (systematic name 8-hydroxy-7-quinolinecarboxaldehyde) and mixed ligand have been prepared. The amine exchange reaction of coordinated Schiff base in these complexes has also been carried out, which gives symmetrical tetradentate Schiff base complexes. The complexes are characterized by elemental and thermal analysis, IR, magnetic and electronic spectral analysis methods were also employed as well as conductivity measurements. An octahedral structure is proposed for all the new complexes in which chloride is attached to the metal ion in 1:1; 1:2 (metal:ligand) ratio. The spectral data were utilized to compute the important ligand field parameter B, beta and Dq. The B-values suggest a strong covalency in the metal-ligand sigma-bond and the Dq-values indicate a medium strong ligand field. 1H NMR spectra show that the tris (ligand) complex is cis isomer. IR spectra show that the ligand is mono-basic bidentate.
