Himanshu Agarwal

Synthesis, Magneto-Spectral and Thermal Studies of Cobalt(II) and Nickel(II) Complexes of 4-[N-(4-Dimethylaminobenzylidene) amino] Antipyrine

Abstract Reactions of MX2 (M = Co or Ni, X = C1−, Br−, I−, NO− 3, NCS−, or C1O− 4) with 4-[N-(4-dimethylaminobenzylidene) -amino] antipyrine (DABAAP) yielded complexes of the type [M(DABAAP)2X2] or [M(DABAAP) 3](C1O4)2. The IR spectra of these complexes indicate that the ligand is a neutral bidentate ligand coordinating through the azomethine nitrogen and carbonyl oxygen. All the complexes are six coordinated according the data of magnetic and electronic spectral measurements. Referee I: Y. Fukuda Referee II: S. Yamada

Synthesis, Biological, Spectral, and Thermal Investigations of Cobalt(II) and Nickel(II) Complexes of N-Isonicotinamido -2',4'-Dichlorobenzalaldimine.

A new series of 12 complexes of cobalt(II) and nickel(II) with N-isonicotinamido-2′,4′-dichlorobenzalaldimine (INH-DCB) with the general composition MX2 · n(INH-DCB) [M = Co(II) or Ni(II), X = Cl− ,Br−, NO3−, NCS−, or CH3COO−, n = 2; X = ClO4 −, n = 3] have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, infrared, electronic spectra, magnetic susceptibility, and conductivity measurements. An octahedral geometry has been suggested for all the complexes. The metal complexes were screened for their antifungal and antibacterial activities on different species of pathogenic fungi and bacteria and their biopotency has been discussed.

Chelating Behaviour of 4[N-(Benzylidene)amino]-antipyrine Semicarbazone Towards Lanthanide Ions

Abstract A series of lanthanide(III) nitrate chelates of 4[N-(benzylidene)amino]antipyrine semicarbazone (BAAPS) with the general composition [Ln(BAAPS) (NO3)3] (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy or Ho) have been synthesized in ethanol. All chelates were characterized on the basis of element analyses, conductance measurements, magnetic moments, infrared and electronic spectra. Their nephelauxetic ratios (β), covalency factors (b½), Sinha parameters (δ %) and angular overlap parameters (η) have been calculated for the Pr(III), Nd(III) and Sm(III) complexes, which indicate some covalent character of these complexes. Thermal stabilities of the complexes were also studied.

Synthesis and Stereochemistry of Dioxouranium(VI) Coordination Compounds of Thiosemicarbazones Derived from 4-Aminoantipyrine

Abstract A series of eight-, nine-and ten-coordinated compounds of dioxouranium(VI) with 4[N-(benzylidene)-amino_7antipyrinethiosemicarbazona (BAAPT), 4]N-(4-methoxy benzylidene) amino_7antipyrinethiosemicarbazone (MBAAPT) and 4[N-(4-hydroxy-3-methoxybenzylidene)-amino_7antipyrinethiosemicarbazone (HMBAAPT) with the general composition UO2X2] nL (X = Br, I, NCS or C104, n = 2; X = NO3 or CH 3COO, n = 1, L = BAAPT, MBAAPT or HMBAAPT) were synthesized in non-aqueous solvent. These complexes were characterized by various physico-chemical techniques. Thermal stabilities of these compounds were also investigated.

Studies on Some Thorium(IV) Complexes with High Coordination Numbers Derived from Semicarbazones of 4‐Aminoantipyrine

Abstract The interaction of thorium(IV) salts with 4[N‐(benzylidene)amino]antipyrine semicarbazone (BAAPS), 4[N‐(4′‐methoxybenzylidene)amino]antipyrine semicarbazone (MBAAPS), 4[N‐(4′‐dimethoxyaminobenzylidene)amino]antipyrine semicarbazone (DABAAPS), 4[N‐(2′‐nitrobenzylidene)amino]antipyrine semicarbazone (2′‐NO2BAAPS), and 4[N‐(3′‐nitrobenzylidene)amino]antipyrine semicarbazone (3′‐NO2BAAPS) in non‐aqueous solvents resulted in the formation of [ThL2X4] (X = Cl, Br, or NCS), [ThL2I2]I2, [ThL2](ClO4)2 or [ThL(NO3)4] (L = BAAPS, MBAAPS, DABAAPS, 2‐NO2BAAPS, or 3‐NO2BAAPS). All of these compounds were characterized by elemental analyses, electrical conductivity, IR, and thermal methods. X‐ray powder diffraction studies of a representative complex were also undertaken. Th(IV) displays the coordination numbers 6, 8, 10, and 11 in these compounds depending on the nature of the coordinated anion and the stoichiometry.

Synthesis, Magnetic, Spectral and Thermal Studies of Some Lanthanide Nitrate and Isothiocyanate Complexes with 4[N-(4-Dimethylaminobenzylidine)amino] Antipyrine

Abstract A new series of complexes of lanthanide(III) nitrate and isothiocynates with 4[N-(4-dimethylaminobenzylidene)amino]-antipyrine (DABAAP) having the general formula [Ln(DABAAP)2(NO3)3] (where Ln = La, Pr, Nd, Sm, Gd, Tb or Dy) and [Ln (DABAAP)n(NCS)3] (n=2, Ln = La or Pr; n = 3, Ln = Nd, Sm, Gd, Tb, or Dy) have been synthesized and their i.r. and electronic spectra obtained. In these complexes DABAAP acts as a bidentate ligand coordinating through the carbonyl oxygen and azomethine nitrogen atoms. The nitrate ion acts as a bidentate ligand and the isothiocyanate ion is N-coordinating with the lanthanide ion. The probable coordination number of the Ln3+ ion varies among seven, nine and ten. The thermal stability of the complexes have also been studied through t.g. analyses. Referee I: J. L. Burmeister Referee II: G. R. Choppin

Magneto, Spectral and Thermal Investigations of Some Lanthanide(III) Complexes of 4[(N-Cinnamalidene)-Amino]Antipyrine

Abstract Complexes of lanthanide(III) nitrates, isothio-cyanates and perchlorates with 4[(N-cinnamalidene)-amino]antipyrine (CAAP) with the general composition, LnX3ňAAP (X = NO3, n = 2, Ln = La, Pr, Nd, Sm, Gd, Tb or Dy; X = NCS, n = 2, Ln = La or Pr, n = 3, Ln = Nd, Sm, Gd, Tb or Dy; X = C104, n = 4, Ln = La, Pr, Nd, Sm, Gd, Tb or Dy) have been synthesized and characterized by various physico-chemical techniques. IR data reveal that CAAP is N-, O-donor ligand. The probable coordination number of the metal varies from seven to ten depending on the nature of anion. Thermal stabilities of these compounds were also investigated.

Chitosan-Based Polymer Electrolyte Membranes for Fuel Cell Applications

Fuel cells have been receiving attention due to its potential applicability as a good alternative power source. Recently, cost-effective and eco-friendly biopolymer chitosan has been devised as membrane in electrolytes and electrodes in direct methanol fuel cell, alkaline fuel cell and biofuel cell applications . This paper reviews structure and property of chitosan with respect to its applications in fuel cells. In addition, different synthetic strategies to prepare chitosan-based polymer electrolyte membranes and their properties for the use in fuel cells are critically examined. These strategies include chemical modifications of chitosan, blending with other polymers and their composites for polymer electrolyte membranes among fuel cell applications. Recent achievements and prospect of its applications have also been included.

Synthesis, Structural, and Thermal Aspects of Dioxouranium(VI) Coordination Compounds of Semicarbazones Derived from 4‐Aminoantipyrine

Abstract A series of 18 new coordination compounds of dioxouranium(VI) with semicarbazones of 4‐aminoantipyrine, viz., 4[N‐(p‐dimethylaminobenzylidene)amino]antipyrine semicarbazone (DABAAPS), 4[N‐(2′‐nitrobenzylidene)amino]antipyrine semicarbazone (2′‐NO2BAAPS), and 4[N‐(3′‐nitrobenzylidene)amino]antipyrine semicarbazone (3′‐NO2BAAPS) of the general composition [UO2L2X2] (X = Br, I, or NCS), [UO2L2](ClO4)2, [UO2L(NO3)2], and [UO2L(OOCCH3)2] (L = DABAAPS, 2′‐NO2BAAPS, and 3′‐NO2BAAPS) were synthesized in non‐aqueous solution and characterized on the basis of elemental analyses, electrical conductivity, magnetic moments, and IR spectral studies. In all of the complexes, these ligands act as neutral tridentate (N, N, O) ligands. In all dioxouranium(VI) complexes, the ν1 and ν3 modes are assigned to 845–825 cm−1 and 930–910 cm−1, respectively. Wilsons G‐F matrix method was used to determine the stretching and interaction force constants from which the U–O bond distances were calculated using Badgers formula. The probable coordination number of U(VI) varies from 8–10 in these complexes. The thermal properties of these compounds are also discussed.

Thorium(IV) Metal Complexes with Neutral Nitrogen Donor Ligands – A Review

The present review presents a discussion of Th (IV) metal complexes with neutral nitrogen donor ligands including Schiff base ligands. This review contains 111 references up to 2006.