NOPR Collection:

Determination of small quantities of nicotinic acid in presence of nicotinamide by modified Konig reaction

2016-07-20T04:23:07Z

Title: Determination of small quantities of nicotinic acid in presence of nicotinamide by modified Konig reaction Authors: Khan, Seemab; Rai, M K; Gupta, V K; Rai, J K Abstract: A modified sensitive spectrophotometric method for the determination of nicotinic acid and nicotinamide in sub-microgram levels is described. During their reaction with cynogen bromide, the pyridine rings are split by the Konig reaction and the reaction products are coupled with diazotised, p-aminoacetophenone, p-aminobenzoic acid, sulphanilic acid and H-acid to form coloured azo dyes. The colour system obeys Beer’s law over the concentration range of 0.008-0.08 ppm, 0.02 -0. 16 ppm, 0.04-0.36 ppm and 0.05-0.4 ppm for nicotinic acid respectively. Similarly, the colour system obeys Beer’s law over the concentration range of 0. 02- 0.2 ppm. 0.04-0.4 ppm, 0.05 -0.56 ppm and 0.07-0.6 ppm for nicotinamide using PAA P, PABA, sulphanilic acid and H-acid respectively. p-Aminoacetophenone gives the best result for the determination of nicotinic acid/ nicotinamide. The sensitivity of the method after this modification is found to be about eight times more than that of the conventional Konig reaction . The method is free from interference of common diverse ion and has been satisfactorily applied to the determination of nicotinic acid in presence of nicotinamide in food, blood, urine and pharmaceuticals. Page(s): 98-101

Synthesis, characterization and solid state structural studies of oxovanadium (IV) - O, N donor Schiff base chelates

2016-07-20T04:22:25Z

Title: Synthesis, characterization and solid state structural studies of oxovanadium (IV) - O, N donor Schiff base chelates Authors: Mishra, A P; Pandey, L R Abstract: VO(IV)-complexes with the Schiff bases viz., 4-chlorobenzylidene-2-amino-4-chlorophenol (CAP), 4-dimethylaminobenzylidene-2-aminophenol (DAP) and 2-hydroxy-1-naphthylidene-4-bromoaniline (HBA) have been synthesized and characterized by elemental analyses, molar conductance, electronic spectra, FT-IR, ¹H-NMR, ESR, FAB mass, thermal and magnetic susceptibility measurements. FAB mass and thermal data show degradation of complexes. Synthesized complexes have been tested for their reactivity and substitution behaviour. All the three ligands behave as bidentate coordinating through O and N donor. The proposed geometry for the complexes is square pyramidal. X-ray powder diffraction data show that two complexes are crystallized in tetragonal system. Solid state AC electrical conductivity studies reflect semiconducting behaviour of complexes. Page(s): 94-97

Mixed ligand triphenylphosphine/arsine Schiff base complexes of ruthenium(II) and their catalytic activities towards oxidation of alcohols

2016-07-20T04:21:49Z

Title: Mixed ligand triphenylphosphine/arsine Schiff base complexes of ruthenium(II) and their catalytic activities towards oxidation of alcohols Authors: Viswanathamurthi, P; Geetha, A; Karvembu, R; Natarajan, K Abstract: Mixed ligand ruthenium(II) complexes [Ru(CO)(Y)(L)], where Y = PPh₃, AsPh₃, pyridine (py) or piperidine (pip) and H₂L = Schiff bases derived from the condensation of o-aminophenol, o-aminothiophenol and anthranillic acid with acetyl acetone in 2:1 molar ratio, obtained from the reactions of [RuHX(CO)(EPh₃)₂(Y)] (X = H or Cl ; E = P or As) with H₂L, have been found to show catalytic activity in the oxidation of alcohols to aldehydes. Page(s): 90-93

Synthesis and characterization of some new Cu(II) complexes of azo dyes derived from 1,2-dihydro-1,5 -dimethy1-2-pheny 1-4-amino-3H-pyrazol-3-one

2016-07-20T04:21:28Z

Title: Synthesis and characterization of some new Cu(II) complexes of azo dyes derived from 1,2-dihydro-1,5 -dimethy1-2-pheny 1-4-amino-3H-pyrazol-3-one Authors: Nair, M L Harikumaran; Mathew, George; Kumar, M R Sudarsana Abstract: Some novel complexes of the ligands 1,2-dihydro-1,5- dimethyl-2-phenyl-4-(2-hydroxy-5-methyl phenylazo)-3H-pyrazol- 3-one (CAAPH) and 1,2-dihydro-l,5-dimethyl-2-phenyl-4- (2-hydroxy-5-chlorophenylazo)-3H-pyrazol-3-one (CPAAPH) with Cu(II) having the formulae [Cu(LH)Cl₂), [CuLH(Ac)₂] [CuLH(NO₃)₂ ] [CuLH(SO₄)], [CuLH(ClO₄)₂ ], [CuLH(NCS)Cl] and [Cu(L H)Cl₂], [CuL’H (Ac₂)], [CuL’ - (NO₃)₂], [CuL’H (SO₄)], [CuL’H (ClO₄)₂], [CuL’H (NCS)Cl] (LH=CAAPH and L H =CPAAPH) have been synthesized and characterized by elemental analysis, IR, electronic, ESR, NMR, magnetic, conductance measurements and cyclic voltammetric studies. The ligands are found to behave in a neutral bidentate manner. All the complexes are non-electrolytes and square planar with magnetic moment ranging from 1.79 to 1.88 B.M. The X-band ESR spectra of the complexes [Cu(CAAPH)Cl₂], [Cu(CAAPH)-(Ac₂], [Cu(CAA PH)(NO₃)₂], [Cu (CAA PH)(SO₄)], [Cu(CPAAPH)(ClO₄)₂] and [Cu(CPAAPH)(NCS)Cl] are seen to be characteristic of Cu(II) in the ligand field with axial symmetry. The complexes [Cu (CAAPH)(SO₄)] and [Cu(CPAAPH)Cl₂)] are found to be orthorhombic with the unit cell dimensions such as a=5.8564 , Å, b=9.4817 Å and c=12.8383 Å; and a=5.3029 Å, b=10.2028 Å and c=11.6127 Å, respectively. The cyclic voltammograms of [Cu(CAAPH)Cl₂] and [Cu(CPAAPH)(Cl O₄)₂] show quasi-reversible peaks which indicates that metal-ligand linkage is more covalent in nature²⁹. Page(s): 85-89