• Periodicity in the formation constant values of lanthanide(III). aminopolycarboxylate. resorcinol/orcinol/phloroglucinol mixed ligand complexes

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    • Keywords


      Periodicity in formation constants; Ln(III).aminopolycarboxylate resorcinol; orcinol; phloroglucinol; ternary complexes

    • Abstract


      Formation constants (logKMALMA) of mixed ligand complexes[Ln(III).A.L.], where Ln(III) = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+ or Dy3+; A=NTA, HEDTA or EDTA and L = resorcinol (res), orcinol (orc) or phloroglucinol (phl) have been determined pH-metrically using the Irving-Rossotti approach at 25°C and at an ionic strength,I = 0·2(mole dm−3, NaClO4). The logKMALMA values lie in the sequence: (i) NTA > HEDTA > EDTA and (ii) orc > res > phl with respect to primary (A) and secondary (L) ligands, respectively.

      Periodicity has been observed in the formation constant values, which lie in the sequence La3+ < Ce3+ < Pr3+ < Nd3+ < Sm3+ < Eu3+ > Gd3+ < Tb3+ < Dy3+ with respect to Ln(III) ions. The evaluated extrastabilization and nephelauxetic ratio values lend support to inter-electronic repulsion theory; these values and the magnitude of the tetrad effect lie in the sequencef7>f3f4f10f11. Hydration numbers (HN) of Ln(III) ions have been calculated; tetrad effect is present in HN.

    • Author Affiliations


      Sangeeta Verma1 S N Limaye1 M C Saxena1

      1. Department of Chemistry, Dr H S Gour Vishwavidyalaya, Sagar - 470 003, India
    • Dates

  • Journal of Chemical Sciences | News

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