Novel ligation of some rare earth metal supramolecular polymer complexes

Summary

Novel seven, nine and ten-coordinated rare earth polymer complexes of N-Acryloyl-1-phenyl-2-thiourea (APT) of the composition [Ln(NO₃)₃(APT)₂]_n (Ln = La, Sm, Tb, Pr and Nd) and [Ln(NCS)₃(APT)_x]_n (where Ln = La or Pr at x = 2 and Ln = Nd, Sm and Tb at x = 3 ) have been prepared and characterized on the basis of their chemical analyses, magnetic measurements, conductance, visible and IR spectral data. The electronic spectra of Pr³⁺, Nd³⁺ and Sm³⁺ show characteristic f-f transitions and the nephelauxetic effect (1-B) of these transitions has been evaluated. These data indicate the weak involvement of the 4f orbitals in complex formation. Composition and IR spectral data of the obtained polymeric complexes show that APT acts as a bidentate ligand. The structure and bonding of these high coordination number compounds were established and identified with the help of various physico-chemical studies. Conductance studies indicate a non-electrolytic behavior for these complexes. Their infrared spectra show that both the ligand and the nitrate group are bound to the metal ion in a bidentate fashion.