Antipyrylmethylidene)aminoantipyrine Research Articles

A comparative thermal decomposition kinetics on 1,2-bis(imino-4'-antipyrinyl)ethane and 4-N-(4'-antipyrylmethylidene)aminoantipyrine Cu(II) complexes with varying counter anions

A comparative thermal decomposition kinetic studies of Cu(II) complexes of 1,2-bis (imino-4-antipyrinyl) ethane(GA) and4-N-(4'-antipyrylmethylidene) aminoantipyrine (AA) with a variety of counter anions viz. ClO4-, NO3-, Cl- and Br- has been evaluated by TG analysis. The kinetic parameters activation energy (E), pre-exponential factor (A) and entropy of activation (∆S) were calculated by using Coats–Redfern equation. This study shows that the thermal decomposition kinetics has been controlled by the ligand field as well as the counter anions.

Ligand Field and Counter Anion Effects on the Thermal Stability of Copper(II) Complexes of 1,2-Di(imino-4’-antipyrinyl)ethane and 4-N-(4’-antipyrylmethylidene) aminoantipyrine

A comparative thermolytic investigation on copper(II) complexes with two antipyrine Schiff base derivatives, namely 1,2-Di(imino-4’-antipyrinyl)ethane (GA) and 4-N-(4’-antipyrylmethylidene) aminoantipyrine (AA), with different counter anions like perchlorate,nitrate, chloride, and bromide has been done by thermogravimetric and derivative thermogravimetric analysis. The present investigation reveals that the counter anions and the ligand field play a big role on the thermal stability of the copper (II) complexes of both Schiff base derivatives. For the present complexes, the thermal decomposition mechanism has been investigated according to Satava, which follows a ‘random nucleation with one nucleus on each particle, i.e. the Mampel model’.

Thermal decomposition studies on cobalt(II) complexes of 4-N-(4?-antipyrylmethylidene)aminoantipyrine with varying counter ions

The phenomenological, kinetic and mechanistic aspects of the nitrate, chloride, bromide and iodide complexes of cobalt(II) with 4-N-(4’-antipyrylmethylidene)aminoantipyrine (AA) have been studied by TG and DTG techniques. The kinetic parameters such as activation energy, pre-exponential factor and entropy of activation were computed. The rate controlling process at all stages of decomposition is random nucleation with one nucleus on each particle (Mampel model)

Synthesis and thermal studies on iron(III) complexes of 4- N-(4′-antipyrylmethylidene)aminoantipyrine with varying counter ions

Iron(III) complexes of the Schiff base 4- N-(4′-antipyrylmethylidene)aminoantipyrine (AA) with counter ions, such as, perchlorate, nitrate, thiocyanate, chloride and bromide have been prepared and characterized by elemental analyses, electrical conductance in non-aqueous solvents, IR and electronic spectra, magnetic susceptibility measurements as well as by thermogravimetric analysis. The complexes have the general formulae [Fe(AA) 2(ClO 4)](ClO 4) 2, [Fe(AA) 2X 2]X (X=NO 3 − or Br −) and [Fe(AA)X 3] (X=SCN − or Cl −). In complexes, AA acts as a neutral bidentate ligand, coordinating through one of the carbonyl oxygens and azomethine nitrogen in perchlorate, nitrate and bromide complexes while the coordination of AA occurs in a neutral tridentate fashion through both carbonyl oxygens and azomethine nitrogen in thiocyanate and chloride complexes. In the perchlorate complex, one of the perchlorate ions is coordinated bidentately while in the nitrate complex two of the nitrate ions are coordinated monodentately to the metal ion. In the thiocyanate and chloride complexes all the anions are coordinated while in the bromide complex two of the bromide ions are coordinated. A high spin octahedral geometry is assigned to the iron(III) ion in all these complexes. The phenomenological, kinetic and mechanistic aspects of the nitrate, thiocyanate, chloride and bromide complexes were studied by TG and DTG techniques. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation were also computed. The rate controlling process in all stages of decomposition is random nucleation with one on each particle (Mampel model) [Thermochim. Acta 2 (1971) 423].

COPPER(II) COMPLEXES OF 1,2-DI(IMINO-4′-ANTIPYRINYL)ETHANE AND 4-N-(4′-ANTIPYRYLMETHYLIDENE)AMINOANTIPYRINE

Copper(II) complexes of the Schiff bases 1,2-di(imino-4′-antipyrinyl)ethane (GA) and 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) have been synthesized and characterized by elemental analyses, electrical conductance in non-aqueous solvents, infrared, electronic and EPR spectra as well as magnetic susceptibility measurements. The complexes have the general formulae [Cu(GA)]X2 (where X = ClO4 or NO3), [Cu(GA)X2] (where X = Cl or Br), [Cu(AA)2]X2 (where X = ClO4, NO3 or Cl) and [Cu(AA)Br]Br. GA acts as a neutral tetradentate ligand coordinating through both carbonyl oxygens and both azomethine nitrogens. In the perchlorate and nitrate complexes of GA, both anions remain ionic while in the corresponding halide complexes both anions are coordinated to the metal ion. AA acts as a neutral bidentate ligand coordinating through one of the carbonyl oxygens and the azomethine nitrogen in the perchlorate, nitrate and chloride complexes, while the coordination of AA occurs in a neutral tridentate fashion through both carbonyl oxygens and the azomethine nitrogen in the bromide complex. In the perchlorate, nitrate and chloride complexes of AA both anions remain ionic, while in the bromide complex, one of the bromides is coordinated to the metal ion. A square-planar geometry is assigned around the Cu(II) ion in all these complexes except the chloride and bromide complexes of GA, which are of distorted-octahedral geometry.

Complexes of Nickel(II) with 1,2-DI(imino-47′-antipyrinyl)Ethane and 4-N-(4′-antipyrylmethylidene)aminoantipyrine

Nickel(II) complexes of the Schiff bases 1,2-di(imino-4′-antipyrinyl)ethane (GA) and 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) having the compositions [Ni(GA)]X2 and [Ni(AA)2]X2 (where X - ClO4, NO3, Cl, Br or I) have been prepared and characterized by elemental analyses, electrical conductance in non-aqueous solvents, infrared and electronic spectra as well as magnetic susceptibility measurements. GA acts as a neutral tetradentate ligand coordinating through both carbonyl oxygens and both azomethine nitrogens while AA acts as a neutral bidentate ligand coordinating through one of the carbonyl oxygens and the azomethine nitrogen. In all these complexes both the anions are not coordinated resulting in a square planar geometry around the Ni(II) ion in complexes of GA and a tetrahedral geometry in complexes of AA.

Cobalt(II) complexes of 1,2-(diimino-4′-antipyrinyl)ethane and 4-N-(4′-antipyrylmethylidene)aminoantipyrine

Cobalt(II) complexes of the Schiff bases 1,2-(diimino-4′-antipyrinyl)ethane (GA) and 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) have been prepared and characterised by elemental analysis, electrical conductance in non-aqueous solvents, i.r. and electronic spectra, as well as by magnetic susceptibility measurements. The complexes have the general formulae [Co(GA)X]X (X = ClO−4 or NO3−), [Co(GA)X2] (X = Cl−, Br− or I−), [Co(AA)2]X2 (X = ClO4−, NO3−, Br− or I−) and [Co(AA)Cl2]. GA acts as a neutral tetradentate ligand, coordinating through both carbonyl oxygens and both azomethine nitrogens. In the perchlorate and nitrate complexes of GA one anion is coordinated in a bidentate fashion, whereas in the halide complexes both anions are coordinated to the metal, generating an octahedral geometry around the Co ion. AA acts as a neutral bidentate ligand, coordinating through the carbonyl oxygen derived from the aldehydic moiety and the azomethine nitrogen. Both anions remain ionic in the perchlorate, nitrate, bromide and iodide complexes of AA, whereas both anions are coordinated to the metal ion in the chloride complex, resulting tetrahedral geometry around the Co ion.

Thermal decomposition kinetics and mechanism of lanthanide perchlorate complexes of 4- N-(4′-antipyrylmethylidene)aminoantipyrine

The thermal decomposition behaviour of lanthanide perchlorate complexes of the Schiff base, 4- N-(4′-antipyrylmethylidene)aminoantipyrine (AA), have been studied using TG and DTG analyses. The phenomenological and kinetic aspects of the TG curves are investigated for the evaluation of kinetic parameters such as activation energy, pre-exponential factor and entropy of activation using the Coats-Redfern equation. The rate controlling process obeys the ‘Mampel model’, representing random nucleation with one nucleus on each particle. There is no regular variation in the values of kinetic parameters for the decomposition of these complexes. The kinetic parameters indicate that the ligand is loosely bound to the metal ion and the activated complex is more ordered than the reactants.

Iodide Complexes of Yttrium and Lanthanides with 4-N-(4′-Antipyrylmethylidene)aminoantipyrine

Abstract Yttrium and lanthanide iodide complexes with the Schiff base 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) of the composition [Ln(AA)2I]I2 (where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er) have been synthesized and characterized by elemental analyses, electrical conductance in non-aqueous solvents, magnetic susceptibility measurements, IR, electronic (in the solid and liquid states) as well as proton NMR (M = La and Y) spectra and thermogravimetric analyses. The Schiff base AA acts as a neutral tridentate ligand in all these complexes, coordinating through the oxygens of both carbonyl groups and the azomethine nitrogen. Only one of the iodide ions is coordinated to the metal ion. A coordination number of seven may be assigned to the metal ion in these complexes.

Complexes of Rare Earth Perchlorates with 4-N-(4′-Antipyrylmethylidene)aminoantipyrine

Abstract Rare earth perchlorate complexes with the Schiff base 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) of the types [Ln(AA)2ClO4](ClO4)2 (where Ln = La, Pr, Nd, Sm and Eu) and [Ln(AA)3](ClO4)3 (where Ln = Gd, Dy, Ho, Er and Y) have been synthesised and characterised. In these complexes AA acts as a terdentate ligand. One of the perchlorate groups is coordinated monodentately only in the complexes of the light rare earths, whereas in the heavy rare earths perchlorate groups remain uncoordinated. The magnetic moments of these complexes agree well with the van Vleck values, suggesting non-participation of f-electrons in bonding.

Synthesis and physicochemical studies of the chloride and bromide complexes of yttrium and lanthanides with 4-N-(4′-antipyryl-methylidene)aminoantipyrine

Twenty new complexes of chlorides and bromides of yttrium and lanthanides with the Schiff base 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) have been prepared and characterised. They have the general formula, [Ln(AA)2Cl3] and [Ln(AA)2Br2]Br where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er. Molar conductance studies indicate slight dissociation for the chloride complexes and 1:1 electrolytic behaviour for the bromide complexes. The magnetic moments of all the complexes agree well with Van Vleck values. The infrared spectra reveal that AA functions as a terdentate ligand in all these complexes coordinating through the oxygens of both the carbonyl groups and the azomethine nitrogen. Electronic spectra of Nd, Ho and Er for the chloride complexes and that of Pr, Nd, Ho and Er for the bromide complexes show weak covalency in the metal-ligand bond.

Complexes of yttrium and lanthanide nitrates with 4-N-(4′-antipyrylmethylidene)aminoantipyrine

Yttrium and lanthanide nitrate complexes with the Schiff base 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) of the composition of [Ln(AA) 2(NO 3) 2]NO 3 (where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er) have been synthesized and characterized by elemental analyses, electrical conductance in non-aqueous solvents, magnetic susceptibility measurements, IR, electronic and proton NMR spectra and thermogravimetric analyses. The Schiff base AA acts as a tridentate ligand in all these complexes, coordinating through the oxygens of both carbonyl groups and the azomethine nitrogen. Only two of the nitrate ions are coordinated monodentately to the central metal ion, while the third remains uncoordinated.