Vinod P. Singh

Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with acetylacetone bis-benzoylhydrazone and acetylacetone bis-isonicotinoylhydrazone

SummaryAcetylacetone bis-benzoylhydrazone (PhCONHN=CMe)2 CH2(LH2) and acetylacetone bis-isonicotinoylhydrazone (NC5H4CONHN=CMe)2CH2(L′H2) complexes of the types [ML] and [ML′] (M = CoII, NiII, CuII or ZnII) have been prepared and characterized. All the complexes are non-electrolytes and the cobalt(II) complexes are lowspin, the nickel(II) complexes are diamagnetic and the copper(II) complexes are paramagnetic. The ligands chelate via two C=N groups and two deprotonated enolate groups. The e.s.r. spectra of the copper(II) complexes indicate a tetragonally distorted dimeric structure. The X-ray diffraction parameters for [CoL] and [NiL′] correspond to a tetragonal crystal lattice.

A highly sensitive and selective fluorescent sensor for Al3+ ions based on thiophene-2-carboxylic acid hydrazide Schiff base

An efficient fluorescent receptor (E)-N-[(2-hydroxy-naphthalen-1-yl)methylene]thiophene-2-carbohydrazide (THN) for Al3+ ions was synthesized and characterized by physicochemical and spectroscopic tools along with single crystal X-ray crystallography. This is the first report showing the crystal structure of THN and its sensing property for Al3+ ions. THN selectively and sensitively detects Al3+ ions without any interference among various cations, Na+, K+, Ca2+, Cr3+, Mg2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Hg2+ by a strong fluorescent change in ethanol–water medium (EtOH–H2O, 1 : 4 v/v). The THN interacts with Al3+ in a tridentate mode to form a [AlCl2(THN)(H2O)]·H2O complex. The binding constant was determined to be 7.06 × 106 M−1 and the limit of detection (LOD) was calculated to be 1.35 × 10−9 M which is the second highest reported till date in the literature. The 1H NMR titration, ESI-MS and DFT studies have also been performed in support of the binding details of the THN–Al3+ complex.

Synthesis, characterization and physicochemical studies of some copper(II) tetrathiocyanato dithallate(I) complexes with hydrazides and hydrazones

Abstract Copper(II) complexes of the type Cu[Tl(SCN2]2·L [where L = benzoic hydrazide (BH), isonicotinic hydrazide (INH), salicyclic hdyrazide (SH), anthranilic hydrazide (AH), p-hydroxybenzoic hydrazide (PHBH), p-aminobenzoic hydrazide (PABH) and their isopropanone derivatives, i.e. isopropanone benzoylhdyrazone (IBH), isopropanone isonicotinoyl hydrazone (IINH), isopropanone salicyloylhydrazone (ISH) and isopropanone anthranoylhydrazone (IAH)] were synthesized and characterized. All the complexes are non-electrolytes, and dissociate in H2O, C2H5OH, CH3CN and CH3COCH3. They are either coordinated through CO and NH2 groups of the hydrazide or CO and CN of the hydrazone ligands. The electronic and ESR spectra suggest a planar geometry for Cu[Tl(SCN2]2 and a tetragonally distorted octahedral structure for all other complexes. The X-ray diffraction parameters for some of the complexes correspond to a tetragonal crystal lattice.

E.S.R. STUDIES ON ACYLHYDRAZINE AND HYDRAZONE COPPER(II) SULFATE COMPLEXES

SummaryCuII complexes of the [CuL2(SO4)]·nH2O and [CuL′(SO4)(H2O)2]·nH2O type, where L = benzoylhydrazine (PhCONHNH2; BH) or iso-propanone benzoylhydrazone (PhCONHN:CMe2; IBH), L′= iso-nicotinoylhydrazine (NC5H4CONHNH2; INH) or isopropanone iso-nicotinoylhydrazone (NC5H4CONHN: CMe2; IINH); n = 0–2, were prepared and characterized by elemental analyses, molar conductances, and electronic, e.s.r. and i.r. spectral measurements. The electronic and e.s.r. spectra suggest a tetragonally distorted octahedral geometry in the solid state as well as in DMSO solution. The e.s.r. data also reveal an axial symmetry for most of the complexes in the solid state and in DMSO solution at 300 and 77 K, while the complex of IBH is isotropic at 300 K. The ΔMs = 2 transition observed for this complex suggests that it is a dimer. BH and INH bond to CuII through the C-O and NH2 groups, whereas IBH and IINH bond through C-O and C-N groups.

A binuclear Mn(II) complex as an efficient catalyst for transamidation of carboxamides with amines

A binuclear Mn(II) complex has been synthesized and characterized by different structural methods. The complex contains two unique oxo-bridged metal centres and has been explored as an excellent catalyst for transamidation of carboxamides with amines under solvent-free conditions.

Synthesis, physico-chemical investigations and biological studies on Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone isonicotinoyl hydrazone

Complexes of the type [M(painh)(H2O)2X], where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); X = Cl2 or SO4; painh = p-amino acetophenone isonicotinoyl hydrazone, have been synthesized and characterized by spectral and other physico-chemical techniques. The synthesized complexes are stable powders, insoluble in common organic solvents such as ethanol, benzene, carbon tetrachloride, chloroform and diethyl ether, and are non-electrolytes. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) studies show that the organic ligand decomposes exothermically through various steps. TGA and Infrared (IR) spectral studies indicate the presence of coordinated water in the metal complexes. Magnetic susceptibility measurements and electronic spectra suggest that Mn(II), Co(II), and Ni(II) complexes are paramagnetic with octahedral geometry, whereas Cu(II) complexes have distorted octahedral geometry. The neutral bidentate ligand bonds through >C=O and >C=N–groups in all the complexes. Electron Spin Resonance (ESR) spectra in the solid state show axial symmetry for [Cu(painh)(H2O)2(SO4)] and elongated rhombic symmetry for [Cu(painh)(H2O)2Cl2], suggesting an elongated tetragonally-distorted octahedral structure for both complexes. X-ray powder diffraction parameters for two complexes correspond to tetragonal and orthorhombic crystal lattices. The metal complexes show fair antifungal activity against Rizoctonia sp., Aspergillus sp., Stemphylium sp., and Penicillium sp. and appreciable antibacterial activity against Pseudomonas sp. and Escherichia coli.

Synthesis, Characterization, Thermal Studies and Biological Activity of Iron(III) Complexes with some Acylhydrazines

Abstract Iron(III) complexes of the type [FeL2 X2]x-nH2O, where L = benzoylhydrazine (BH), isonicotinoylhydrazine (INH), sali-cyloylhydrazine (SH), oxaloyldihydrazine (ODH) and malonoyl-dihydrazine (MDH); X = Cl–, NO3, SCN– and 1/2 SO4 2-; n =0−3, were prepared and characterized with the help of elemental analyses, molar and solid state conductance, thermal, magnetic, infrared and electronic spectral studies. The complexes are highly insoluble in common organic solvents, decompose above 200°C and are spin free octahedral. The ligands coordinate to the metal atom through >C=O and NH2- The complexes show multi-step exothermic decomposition patterns. The ligands as well as their complexes show moderate antifungal and antibacterial activity.

Synthesis, structural studies and bio-activity of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone salicyloyl hydrazone

Complexes of the type [M(pash)Cl] and [M(Hpash)(H2O)SO4] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH2 and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH2 in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d x 2 − y 2 . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H2O)SO4] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.

N'-[1-(2-Amino-phen-yl)ethyl-idene]benzo-hydrazide.

The title compound, C15H15N3O, was obtained by a condensation reaction between o-aminoacetophenone and benzoyl hydrazine. The molecule displays an E configuration about the C=N bond. Intramolecular N—H⋯N hydrogen bonds are formed between the 2-aminophenyl and imine groups. In the crystal, dimers are formed between molecules linked by intermolecular N—H⋯O hydrogen bonds from the 2-aminophenyl group. In addition there are intermolecular N—H⋯O hydrogen bonds between the amine and carbonyl groups of adjacent molecules. The molecule is twisted rather than planar due to a steric interaction between the central amide group and the two outer benzene rings. The dihedral angles between this central group and the two rings are 23.29 (9) and 24.96 (9)°.

5-FLUOROURACIL AND 5-FLUOROURACIL-HISTIDINE COMPLEXES WITH ALIII, CRIII AND FEIII IONS AND THEIR ANTITUMOUR ACTIVITY

Abstract Complexes of the type [M(L-H)(OH)Cl], [Cr(L-H)(H2O)2(OH)Cl] and [M′(L-H)(L′-H)(H2O)Cl], where L = 5-fluorouracil; L′ = histidine (HISD); M = AlIII or FeIII and M′ = AlIII, CrIII or FeIII were synthesized and characterized. The complexes are insoluble in water and common organic solvents. 5-Fluorouracil is coordinated to the metal ion through the O atom of C4 = O and the N atom of N1 while histidine coordinates through the O atom of −COO− and the N atom of −NH2 groups. The μeff values, electronic spectral bands and ESR spectra suggest a polymeric 6-coordinate spin free octahedral stereochemistry for CrIII and FeIII complexes. The in vivo antitumour effect of 5-fluorouracil and its complexes was examined on C3H/He mice against P815 murine mastocytoma. As evident from their T/C values CrIII and FeIII complexes display significant and higher antitumour activity compared to 5-fluorouracil while the AlIII complexes show lower activity. The in vitro results of the complexes on the same cells indicate that CrIII and FeIII complexes show higher inhibition on 3H-thymidine and 3H-uridine incorporation in DNA and RNA replication, respectively.