Co-ordination behaviour of hydrazine and isomers of acetoxy benzoic acids with transition metal ions

ABSTRACT. New hydrazine complexes of some divalent transition metal ions of formulae,                           [M{(2-ab)2(N2H4)}].3H2O, [M{(3-ab)2(N2H4)}].3H2O and [M{(4-ab)2(N2H4)2}].2H2O where M = Co, Ni, Zn and Cd; 2-abH = 2-acetoxy benzoic acid, 3-abH = 3-acetoxy benzoic acid and 4-abH = 4-acetoxy benzoic acid were prepared using their respective metal nitrates and hydrazine hydrate at pH 6 and 5, respectively, and characterized by elemental analysis, IR and UV-reflectance spectroscopic techniques, thermo analytical technique, powder XRD, SEM-EDX and magnetic susceptibility measurements. All the transition metal complexes were sparingly soluble in water. The IR spectra of complexes showed N-N absorptions of hydrazine in the range of 964-988 cm-1 substantiating the bidentate bridging coordination of hydrazine. They showed endothermic decomposition in the range of 67-100 °C, exothermic dehydrazination in the range, 210-281 °C and an oxidative decomposition between 350 and 490 °C to form their respective metal oxides. The electronic spectral and magnetic susceptibility data could substantiate the distorted octahedral geometry of nickel and cobalt complexes and the XRD pattern indicates the existence of isomorphism. Crystals of [Cd(H2O)3((C6H4(4-OH)(COO))2].H2O obtained as by-product, was also characterized using single crystal XRD, IR and thermal studies.                     KEY WORDS: Acetoxy benzoic acids, Hydrazine, Thermal analysis, Single crystal XRD   Bull. Chem. Soc. Ethiop. 2021, 35(2), 337-350.  DOI: https://dx.doi.org/10.4314/bcse.v35i2.

Screening for pod shattering in mutant population of mungbean (Vigna radiata (L.) Wilczek)

Mungbean, (Vigna radiata (L.) Wilczek) occupies a unique position in Indian agriculture and has been grown under various agro-ecological conditions. It is cultivated in 1.61mha with production of 3.38MT and productivi-ty of 474kg/ha in India. Mungbean pods are thin and brittle when dry, so shattering is a major problem. The loss of seeds by pod dehiscence is one of the major reasons for low yield in mungbean; thus, reducing the frequency of pod dehiscence is an important objective in mungbean breeding. Induced mutations, have offered a single and short alternative to conventional breeding including isolation, screening, selection and testing generation after generation. In this study, variability was induced by gamma rays and Ethyl methane sulphonate (EMS) in two greengram geno-types viz., CO (Gg) 7 and NM 65. Screening for pod shattering was carried out in M2 and M3 populations of green-gram. The scoring for shattering was recorded at physiological maturity of the pod. The shattering percentage ranged from 14.56 (400 Gy) to 93.45 per cent (20 mM). A total of 100 shattering tolerant mutants were selected from field based on visual observation. These mutants were again scored under laboratory condition as per IITA method. A total of 12 mutants of CO (Gg) 7 and 10 mutants of NM 65 which were tolerant to pod shattering were identified in M2 generation and forwarded to M3 generation. These mutants were scored for pod shattering under laboratory con-dition and nine mutants viz., M26, M44, M46, M58, M70, M71, M84, M92 and M98 were found to be tolerant in M3 generation. This study on identification and screening of the mutants tolerant to pod shattering with high yielding potential will help to increase the production of the pods to a greater extent

3-Hydroxy-2-naphthoate Complexes of Transition Metals with Hydrazine - Preparation, Spectroscopic and Thermal Studies

Reaction of hydrazine and 3-hydroxy-2-naphthoic acid with some transition metal ions forms two types of complexes: (i) [M(N2H4){C10H6(3-O)(2-COO)(H2O) 2] where M=Ni, Co, Cd and Zn, at pH 9 and (ii) [M(N2H5)2{C10H6(3-O)(2-COO)} 2].xH2O where M=Ni & x =1; M=Co, Cd, Mn & x=3; and M=Zn, Cu & x =0 at pH 4. Analytical data confirms the compositions of the complexes. The acid shows dianionic nature in these complexes. The magnetic moments and electronic spectra suggest the geometry of the complexes. IR data indicates the nature of hydrazine and presence of water in the complexes. Simultaneous TG-DTA studies shows different thermal degradation patterns for the two types of complexes. The first type shows formation of no stable intermediates whereas the second type shows the respective metal hydroxy naphthoate intermediates. The final products in both the types are found to be metal oxides of nano size. XRD patterns show isomorphism among the complexes with similar molecular formulae

Synthesis and Thermal Characterization of Lanthanide(III) Complexes with Mercaptosuccinic Acid and Hydrazine as Ligands

Reaction of hydrazine and mercaptosuccinic acid with metal ions forms complexes with general formula [Ln(N2H4)2CH2(COO)CH(SH)(COO)1.5]·(H2O), where Ln = La(III), Pr(III), Nd(III), Sm(III), and Gd(III) at pH 5. The complexes have been characterized by elemental analysis, IR and UV-visible spectroscopic, thermal and X-ray diffraction studies. The IR data reveal that the acid moiety in the complexes is present as dianion due to the deprotonation of COOH groups by lanthanides in these complexes, leaving –SH group unionized and hydrazine as bidental neutral ligand showing absorptions in the range of 945–948 cm−1. The thermoanalytical data evince that the complexes are stable up to 103°C and undergo complete decomposition in the range of 550–594°C resulting in metal oxides. SEM images of La2O3 and Gd2O3 residues show their nano sized clusters suggesting that the complexes may be used as precursors for nano La2O3 and Gd2O3, respectively. X-ray powder diffraction patterns show isomorphism among the complexes. The kinetic parameters of the decomposition of the complexes have been computed by Coats-Redfern equation

Synthesis, characterization, thermal behavior and antimicrobial activity of 3-methyl benzoate complexes of transition metal with hydrazine

Reaction of the ligands, 3-methyl benzoic acid (mbH) and hydrazine with transition metal ions form the complexes of formulae, [M(N2H4)2(mb)2].H2O where M = Co(II) and Zn(II) at pH = 5-6, [M(N2H4)n(mb)2].xH2O where M = Ni(II), n = 2, x = 0 at pH = 5 and M = Cd, n = 1, x = 1 at pH = 6. The same acid also forms metal carboxylates with zinc and copper of formula, [Zn(mb)2H2O].H2O at pH = 6 and [Cu(mb)2].H2O at pH = 5, respectively. The IR spectra of the complexes show that hydrazine is present as bridging bidentate ligand and the carboxylic acid as monodentate bridging carboxylate anion. The electronic spectra, magnetic moments and ESR spectral data suggest the coordination number. Thermal studies show that cobalt, zinc and nickel complexes containing hydrazine, and carboxylates of copper, zinc on their thermal decomposition form the corresponding metal oxides in nano size in the temperature range 755-815 °C. The antibacterial and antifungal activity show that both activities of the complexes are higher than that of the acid and among the complexes, cadmium compound shows more antimicrobial activity towards bacteria and fungi