N.K. Dutt

Chemistry of lanthanons—XVII: Bis-salicylaldehyde ethylenediamine and bis-salicylaldehyde o-phenylenediamine complexes of rare-earths

Abstract A new series of rare-earth metal chelates derived from N-coordinating ligands like bis-salicylaldehyde ethylenediamine (H 2 Salen) and bis-salicylaldehyde o-phenylenediamine (H 2 Salphen) have been prepared with La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb and Y. These compounds are of the general formula Ln 2 (Salen) 3 and Ln 2 (Salphen) 3 (where Ln stands for the above lanthanides except Ce). The cerium complex prepared with H 2 Salen has the composition Ce(Salen) 2 . Many compounds of the former series are solvated and contain ethanol or water molecules. These compounds have been characterised by their thermal analyses and i.r. spectra.

Chemistry of the lanthanons—XIII: The stabilities of the acetylacetonates, propionylacetonates and benzoylacetonates of La, Pr, Nd and Y

Abstract The stabilities of several β-diketonates of La, Pr, Nd and Y have been measured. The complexes have been shown to dissociate stepwise in all the series. Plot of pK values against ionic radii of different lanthanons reveals that the stability increases with decreasing ionic size that is with decreasing basicity.

Organic reagents used in inorganic analysis—V Determination of formation constants of uranium(VI) chelates with several hydroxamic and N-arylhydoxamic acids

Abstract The formation constants of uranium(VI) chelates with nine reagents, six N-arylhydroxamic acids and three hydroxamic acids have been determined by a pH-potentiometric method. Solubility products of the complexes have also been determined from which it appears that the reagents (I–VII and IX) can well be utilised for the gravimetric determination of uranium(VI).

Chemistry of lanthanons-XIX ethylenediamine bis-acetylacetone complexes of rare-earths

Ethylenediamine bis-acetylacetone (enac) complexes of rare-earths are described. Compounds of composition Lc(enac)2 X3, where Ln = La, Ce, Pr, Nd and Sm and X = Cl−, NO3− and SCN− and Ln2(enac)3 X6 where Ln = Gd, Dy, Er and Y and X = Cl− and NO3− have been obtained. On the basis of their u.v. visible and i.r. spectra and also from conductance and molecular weight measurements possible structures for the complexes have been proposed.

Chemistry of lanthanons-XX complexes of the rare earths with 3-mercapto-1-phenylbut-2-en-1-one

Abstract The formation constants of some rare earth complexes of 3-mercapto-1-phenylbut-2-en-1-one have been determined at 0·1 M ionic strength by pH-potentiometric titration in 3:1 ( v/v ) acetone water mixture at 30±0·5°C.

Chemistry of lanthanons…-XXVII: Rare earth complexes of ethylacetoacetate

Abstract A new series of rare earth complexes of ethylacetoacetate (HEAA) having the composition, [Ln(EAA)2(OH)(H2O)] (where Ln stands for the lanthanides) has been prepared. The chelates have been characterised by i.r. spectra. The electronic spectra indicate weak involvement of the 4f orbitals.

Chemistry of lanthanons—XVIII: Mixed chelates of La, Pr, Nd, Sm and Y containing β-diketone and bis-salicylaldehyde ethylenediamine

Abstract Mixed ligand complexes of lanthanides (La, Pr, Nd, Sm) and Y containing botg β-diketone and bis-salicylaldehyde ethylenediamine (H2 Salen) as the associated ligand molecules have been prepared. By reacting tris-acetyl acetonate and tris-propionyl acetonates of the above lanthanides with the Schiffs base in ammoniacal atmosphere compounds obtained were of the type [Ln(diket)2(Salen)0.5] (I), whereas by refluxing the tris-benzoyl acetonates and tris-dibenzoyl methanides with the Schiffs base, a second series of compound viz., [Ln(diket)(Salen)] (II) were obtained. Sodium salts of tetrakisbenzoyl acetonates and dibenzoyl methanides also yield compounds of the second type.

Complexes of nickel(II) with some thiocarbazide derivatives

Abstract Preparation and properties of a series of complexes of Nickel(II) with benzoyl-thiocarbazide (HBTC), acetylthiocarbazide (HATC), nicotinoylthiocarbazide (HNTC), 2-chloro-benzoylthiocarbazide (Cl-HBTC) and 2-hydroxybenzoylthiocarbazide (HO-HBTC) are reported. Three types of complexes [NiL2Cl2], [NiLCl2], 4H2O and NiL2 have been prepared. Electronic spectra in solid state and in solution, magnetic moments and i.r. spectra are used to assign their structures. The ligand field parameters, Dq, B′ and β are calculated. The parameters indicate that the complexes of the class [NiL2Cl2] are pseudotetrahedral, the ligand acting as monodentate and S-coordinating. The [NiLCl2] · 4H2O type complexes are polymeric distorted octahedral involving bridging halogen atoms, as well as a bridging ligand molecule, the ligands in these cases are bidentate, the coordination occurring through sulphur and the end nitrogen atom. Electronic parameters are also calculated. The neutral chelates are paramagnetic and polymeric sulphur bridged structures are assigned to them.

Complexes of cobalt(II) with some thiocarbazide derivatives

Abstract The preparation and properties of a series of complexes of cobalt(II) with benzoylthiocarbazide (HBTC), acetylthiocarbazide (HATC), nicotinoylthiocarbazide (HNTC) and 2-chlorobenzoyl-thiocarbazide (Cl-HBTC) are reported. Four types of complexes (i) [Co(H L ) 2 Cl 2 ], (ii) [Co(H L ) 2 (NO 3 )](NO 3 ), (iii) Co(H L ) 2 Cl 2 ·2·dioxane, and (iv) Co L 2 have been prepared and characterised. The electronic spectra of the solids, magnetic moments and i.r. spectra are used to assign their structures. The ligand field parameters, Dq , B ′ and β for first three types of complexes are also calculated. The parameters indicate that all the complexes are octahedral, the ligands being bidentate and coordinating through the sulphur and the hydrazinic nitrogen atoms. The neutral inner chelates of cobalt(II) (type (iv)) are paramagnetic with moments corresponding to octahedral cobalt(II) complexes and polymeric structures involving bicovalent bridging sulphur atoms analogous to the corresponding nickel(II) chelates, have been assigned to them. X-ray powder diagrams show that neutral inner chelates (type (iv)) are isomorphous with the corresponding nickel(II) chelates whereas the compounds of the type (i) are not.

Chemistry of lanthanons-XXII Hydroxo aquo bis benzoyl acetonates of rare earths and mixed hetero chelates derived from them

Abstract A new series of compounds of rare earth elements with benzoylacetone has been prepared and the mixed hetero chelates obtained have been characterised.