Synthesis and characterization of novel N-functionalized macrocyclic dioxotetraamines bearing 8-hydroxyquinoline and its metal complexes: Stability in aqueous solutions

• Published in: Indian journal of chemistry. Section A, Inorganic, physical, theoretical & analytical Vol. 43; no. 4; pp. 793 - 798
• Main Authors: Zhao, XJ, Su, XC, Yang, EC, Wang, Y, Lin, HK, Zhu, Sun, HW
• Format: Journal Article
• Language: English
• Published: NEW DELHI Natl Inst Science Communication-Niscair 01.04.2004
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; CU2; 5-SUBSTITUTED 1,10-PHENANTHROLINE-COPPER(II)
• ISSN: 0376-4710; 0975-0975

Novel 4-(5'-8'-hydroxyquinoline)methylene-1,4,7,10-tetraaza-cyclotridecane-11,13-dione ligand (L) has been synthesized by simple method, and characterized by elemental analyses, IR and H-1 NMR. It has two chelating sites each able to react with a transition metal ion to form complexes. At 25.0 +/- 0.1 degreesC, I = 0.1 mol/dm(3) NaNO3, potentiometric titrations have been performed to determine the protonation of L-5-R-1,10-phenanthroline-Cu(II) (R = CH3, H, Cl, NO2) and the stability constants of Cu(II) and Co(II). The results show that for Cu(II) and Co(II) complexes, 8-hydroxyquinoline is a stronger chelating reagent than tetraamine[13]ene macrocycles. Molecular mechanics (MM+) calculations have been performed to assess the stability of ternary mixed system on Co(II)-L-5-substituted-1,10-phenanthroline-Cu(II) and Cu(II)-L-5-substituted-1,10-phenanthroline-Cu(II). The coordination ability for different coordination sites and for different metal ions (Co(II) and Cu(II)) at the same sites have been compared. The calculated results agree with those obtained experimentally.