• M S Sastry

      Articles written in Journal of Chemical Sciences

    • Phosphate coordination in copper(II) complexes

      M S Sastry T kesavadas G S Rao M D Sastry

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      The structural aspects of phosphate coordination in Cu(bipy)2 (H2PO4)2∼0·25 H3PO4 (1) and Cu(phen)2(H2PO4)2∼0·25 H3PO4 (2) (bipy=2,2′ bipyridyl; phen=1,10 phenanthroline) have been investigated byir, electronic andesr spectra. In both complexes bidentate coordination from H2PO4 ion is suggested. The complexes have been assignedcis-distorted octahedral stereochemistry. It is interesting that the stereochemistry is essentially of a static nature in (1) while it is fluxional in (2).

    • Mixed metal zinc (II)-molybdenum (VI) peroxo complexes containing some amino acids and acetic acid

      M S Sastry S S Gupta

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      A facile synthesis of the title complexes which involve glycylglycine(Gg) glycine (Gly) and acetic acid (HAc) as ligands is reported. Reaction of equimolar mixtures of zinc and molybdic acid (MoO3·H2O) with Gg, or Gly or Ac, in excess hydrogen peroxide (H2O2) at ambient conditions, results in the formation of novel mixed metal complexes having the general formula, [Zn, Mo(O)2 (O22−)(L)2(H2O)2], (L=Gg or Gly or Ac). These new complexes have been characterised by elemental and thermogravimetric analyses, IR and electronic spectra. It is of interest to note that while heteronuclear peroxo complexes are quickly formed, the corresponding homonuclear Zn complexes could not be obtained.

    • Heteronuclear copper(II)-molybdenum(VI) oxoperoxo complex containing glycine and imidazole

      M S Sastry S S Gupta

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      A facile synthesis of the above titled homogeneous mixed ligand complex is reported. The reaction of equimolar mixture of copper (Cu) and molybdic acid (MoO3.H2O) powders with an aqueous solution of glycine (Hgly) and imidazole (Him) in excess hydrogen peroxide (H2O2), at ambient conditions results in the formation of novel complex [Cu, Mo(O)(O22−)(gly)2(Im)2(H2O)2](1)-Compound1 was characterised by elemental analysis, IR and electronic spectra, and thermogravimetric analysis both in air and argon. It is interesting to find that ESR spectra of1 both at 300 K and 77 K gaveg values characteristic of an axially compressed octahedral geometry (g>g11>2.00), around Cu(II) centre in the heteronuclear complex both in solution and solid phase. It is worth mentioning that the corresponding copper(II)-zinc(II) heteronuclear complex of1 was reported to exhibit an axially elongated octahedral geometry around Cu(II) centre withg11>g>2.00 values.

    • Effect of some transition metals on interactions of simple ammonium carboxylates with hydrogen peroxide

      M S Sastry S S Gupta

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      Reactions of equimolar mixtures of copper (Cu), zinc (Zn) metal powders with either ammonium formate or acetate or tetrabutyl ammonium acetate (1:1:2) in excess hydrogen peroxide (H2O2) at ambient conditions results in decarboxylation yielding mixed metal oxide [Cu, ZnO2·H2O], while the corresponding reaction with ammonium succinate results in formation of mixed metal peroxo carbonate [Cu, Zn(O22−)(CO3)(H2O)2]. Interestingly, in all the above mentioned carboxylates, the corresponding reactions in the presence of H2O2 and imidazole (HIm) results in formation of HIm adducts of mixed metal peroxo carbonates [Cu, Zn(O22−)(CO3)(HIm)x(H2O)2]. It is noteworthy to mention that all the above mentioned reactions in presence of either Cu or Zn powder alone, did not give any homogeneous reaction product, and instead the metal powder remained undissolved. Similarly, it is very significant to observe that the reaction of sodium salts of the above mentioned carboxylic acids with H2O2 in presence of either Cu-Zn mixture or Cu-Zn-HIm mixture did not give any decomposed products and instead the metal powders remained undissolved. Hence this work is of significance as it reports for the first time, the profound effect of the presence of both ammonium ion and carboxylic group in simple carboxylates and its reaction with H2O2 in the presence of Cu-Zn mixture. The new mixed metal peroxo carbonates and the imidazole adducts isolated from the above mentioned reaction systems were characterised by chemical, elemental and thermogravimetric analyses, ESR, electronic and IR spectral studies.

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