Organoselenium/Tellurium-Bearing Macroacyclic and Cyclic Ligand Systems and Their Complexation Reactions
作者:M. Nasim、S. K. Tripathi、S. B. Mishra、B. L. Khandelwal
DOI:10.1080/10426500590906229
日期:2005.2.23
A series of phenol-substitated acyclic Schiff bases, 2,6-RE(CH2)(n)N=C(CH3)](2)C6H2(4-CH3)(OH), (E = Te: R = C6H5, n = 2(L-a), 3(L-b); R = C6H4-4-OCH3, n = 2(L-c), 3(L-d);E = Se:R C6H5, n = 2(L-e), 3(L-f)), of the type E2N2O have been synthesized by condensation of 2,6-diacetyl-4-methylphenol with arylchalcogenoalkylamines. This ligand framework is useful for designing molecular complexes with a variety of coordination modes depending upon the nature of the central metal atom. The reactivity of the tellurium-bearing macroacyclics ligands towards Zn(II), Cd(II), and Hg(II) has been exantined. The ligands L-a-L-d with Zn(II) and Cd(II), and only L-a and L-b with Hg(II) form complexes of composition M2XAL, (X = Cl or Br), whereas L-c and L-d with Hg(II) give products of composition HgBr2L. The modes of ligand interaction with Zn(II) and Cd(II) are different than that with Hg(II).Following a multistep reaction involving abstraction of bridged Br atoms and subsequent addition of more ligand, the mercury complex, Hg2Br4L has been used for developing metallocyclic system of the type [Hg2Br2L2](2+). The latter has been found to encapsulate Zn(II) and Cd(II) to give multimetallic systems.