Ram K. Agarwal

Thorium(IV) and dioxouranium(VI) chelates of aromatic amine N-oxides

Abstract Thorium(IV) and dioxouranium(VI) chelates of 1,10-phenanthroline NN′-dioxide (phenO 2 ) and dioxouranium(VI) chelates of mono N-oxides of 2,2′-bipyridine (bipyNO) and 1,10-phenanthroline (phenNO) of the general composition ThX 4 ·2phenO 2 (X = Cl, Br, NO 3 or NCS); ThX 4 ·3phenO 2 (X = ClO 4 or I); UO 2 X 2 ·2L (X = Cl, Br, and L = bipyNO, phenNO or phen 2 ); UO 2 (NO 3 ) 2 ·L; UO 2 X 2 ·3L(X = ClO 4 or I) and UO 2 (NCS) 2 ·1.5L have been synthesised and characterized employing i.r. spectral, molar conductance, molecular weights, d.t.a. and t.g.a. data. phenO 2 acts as O,O-bidentate ligand while bipyNO and phenNO act as N,O-bidentate ligands. The coordination number of thorium in these complexes is either 6, 8 or 12; in uranium the coordination number is either 7 or 8 depending on the nature of the anions.

Synthesis, Spectral, and Biological Properties of Copper(II) Complexes of Thiosemicarbazones of Schiff Bases Derived from 4-Aminoantipyrine and Aromatic Aldehydes

We have synthesized a novel series of Schiff bases by condensation of 4-aminoantipyrine and various aromatic aldehydes followed by reaction with thiosemicarbazide. These thiosemicarbazones are potential ligands toward transition metal ions. The reaction of copper(II) salts with 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(4′-methoxybenzalidene) amino] antipyrinethiosemicarbozone (MBAAPTS), 4[N-(4′-dimethylamino benzalidene) amino] antipyrinethiosemicarbazone (DABAAPTS), and 4[N-(cinnamalidene) amino] antipyrinethiosemicarbazone (CAAPTS) resulted in the formation of solid complexes with the general composition CuX2 · (H2O)(L)(X = Cl, Br,NO3,NCS, or CH3COO; L = BAAPTS, MBAAPTS, DABAAPTS, or CAAPTS). These complexes were characterized through elemental analysis, molecular weight, electrical conductance, infrared, electronic spectra, and magnetic susceptibilities at room temperature. Copper(II) complexes with BAAPTS and MBAAPTS were screened for antibacterial and antifungal properties and have exhibited potential activity. Thermal stabilities of two representative complexes were also investigated.

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.

Thorium(IV) and zirconium(IV) complexes of oxygen donor ligands, Part 6. thorium(IV) complexes of 2,6-lutidine-N-oxide and tetramethylene sulphoxide

SummaryThe synthesis and physical properties of crystalline thorium(IV) complexes, Th(ClO4)4 · 6 LNO, ThX4 · 2 LNO (X = Br or SCN), ThX4 · 4 LNO (X = NO3 or I) andTh(ClO4)4 · 10 TMSO, Th(NO3)4 · 6 TMSO, ThX4 · 4 TMSO (X = Cl or Br), ThI4 · 6 TMSO and Th(NCS)4 · 2 TMSO (where LNO = 2,6-lutidine-N-oxide and TMSO = tetramethylene sulphoxide) are reported together with their i.r. spectra, molar conductivities, molecular weights, t. g. a. and d. t. a. data. In all the complexes, LNO and TMSO are bonded to thorium(IV) through oxygen. The coordination number of thorium(IV) in these complexes varies from six to ten depending upon the nature of the anions.

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.

Thorium(IV) and zirconium(IV) complexes of oxygen donor ligands, part 12. Thorium(IV) complexes of monoN-oxides of 2,2′-bipyridine and 1,10-phenanthroline

SummaryCrystalline thorium(IV) chelates with monoN-oxides of 2,2′-bipyridine (bipyNO) and 1,10-phenanthroline (phenNO), ThX4 · 2L (X = Cl, Br, NO3 or NCS) and ThX4 · 3L (X = I or ClO4, and I = bipyNO or phenNO) have been synthesised and characterized on the basis of i.r. spectra, molar conductance, molecular weights, t.g.a. and d.t.a. data. All the complexes are weakly diamagnetic and contain bipyNO and phenNO bonded to thorium(IV) through nitrogen and oxygen. The coordination number of thorium(IV) varies from six to twelve depending on the nature of the anions.

Synthesis, Characterization and Biological Evaluation of a Novel Series of Mixed Ligand Complexes of Lanthanides(III) with 4(N-(Furfural)amino)antipyrine Semicarbazone as Primary Ligand and Diphenyl Sulfoxide as Secondary Ligand

A novel series of complexes of lanthanides(III) with 4[N-(furfuralamino]antipyrine semicarbazone (FFAAPS) as the primary ligand and diphenyl sulfoxide (DPSO) as the secondary ligand with the general composition LnX3(FFAAPS)nDPSO (X = NO3-, n = 1; X = NCS- or ClO4-, n = 2; Ln = La3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, Dy3+ or Ho3+), is reported. All the synthesized complexes were characterized through various physico-chemical techniques i.e. elemental analysis, conductance measurements and magnetic susceptibilities, spectroscopic and thermal studies. The coordinated FFAAPS behaved as tridentate N,N,O-donor, while DPSO acted as unidentate oxygen donor. Nitrates were bicovalently bonded, while the thiocyanate was coordinated through N-atom. Perchlorate ions did not participate in the coordination sphere. The absorption bands of the representative Pr(III), Nd(III) and Sm(III) complexes in the visible and near infrared region appeared due to transitions from the ground levels to the excited J-levels of 4f-configuration. From the hypersensitive bands, the nephelauxetic effect (β) was calculated. And from the β-values, the covalence factor (b1/2), Sinha parameter (δ%) and the covalency angular overlap (η) were calculated. The ligand and the corresponding lanthanide(III) complexes were simultaneously screened for their antibacterial and antifungal activities. Thermal stabilities of these complexes were studied by thermogravimetric analysis. Depending on the nature of the anionic ligands, the coordination number of the lanthanide(III) in the case of nitrate or thiocyanate complexes was ten, while it was seven in the case of perchlorate complexes.

Synthesis and magneto-spectral investigations of some six and nine coordinated complexes of lanthanides(III) derived from 4[N-(2′-hydroxy-1′-naphthalidene) amino]antipyrinethiosemicarbazone

The present work describes the synthesis and characterization of some six and nine coordinated complexes of trivalent lanthanide(III) with 4[N-(2′-hydroxy-1′-naphthalidene)amino]antipyrinethiosemicarbazone (HNAAPTS). All the complexes have the general composition LnX3.n(HNAAPTS) (X = NO3−, n = 1; X = NCS− or ClO4−, n = 2). The complexes were characterized through elemental analyses, molar mass, conductivity measurements, magnetic susceptibilities, and infrared and electronic spectra. Infrared spectra revealed that HNAAPTS acts as a neutral tridentate (N,N,S) donor. The coordination number in these complexes is either six or nine depending on the nature of the anionic ligand.

Complexes of hydrazine and substituted hydrazines with some oxocations

SummarySeveral new polymeric complexes of general composition MOn(L)4X2 (where M = V, Zr and U; n = 1 or 2; X = Cl, Br, I, NO3 and NCS and L = N2H4, PhNHNH2 and Me2NNH2 have been synthesised and characterized by elemental and d.t. analyses and by magnetic measurements, electronic and i.r. spectra. The vanadyl(IV) complexes exhibit subnormal magnetic moments (1.26–1.36BM) possibly because of exchange interaction between vanadium(IV) ions. The thermal stability of hydrazine complexes fall in the order: Cl>Br>NCS>I. The M-N bond strength, as revealed, by v(M-N), decreases as: Me2NNH2>N2H4>PhNHNH2.