Organotellurium Ligands & their metal complexes: Recent developments

The ligand chemistry of telluroethers, halotellurium. ligands, and polytellurides has received good attention in the last decade. Tellurium-containing species have been used to design clusters. In the recent past the ligation of di and tri-telluroethers (including bis(4-meethoxyphenylyelluro)methane) has been. studied. Hybrid organotellurium ligands, N-[2-(4-methoxyphenyltelluro)propyl]phthalimide (L-1), 2-(4-ethoxyphenyltelluromethyl)-tetrahydro-2H-pyran (L-2), 2-(2-{4-ethoxyphenyl} telluroethyl)-1,3-dioxane (L-3), N-{2-(4-methoxyphenyltelluro)ethyl}morpholine (L-4), N-{2-(4-methoxyphenyltelluro)ethyl}.pyrrolidine (L-5), bis{2-(pyrrolidine-N-yl)ethyl}telluride (L-6), 1-(4-methoxyphenyltelluro)-2-[3-(6-methyl-2-pyridyl) propoxy]ethane (L-7), and 2-[2-(4-methoxyphenyltelluro)ethyl]thiophene (L-8) have been designed recently and studied for their complexation reactions. The (Te, N) and (N, Te, N) ligands, L5 and L6, coordinate with Hg(11) through Te and N both, but the bonding with N is some what weak. The morpholine nitrogen of L-4 does not coordinate with Pd(II) or Pt(II) along with Te. The L-7 behaving as a (Te, N) ligand has formed 20-membered metallomacrocycle ring with P(II). Tellurated Schiff bases 4-MeOC6H4TeCH2CH2N=C(CH3)C6H4-2-OH (L-9) and 2-HO-C6H4-(CH3)C=NCH2CH2TeCH2CH2N=C(CH3)C6H4-2-OH (L-10) and their reduction products 4-MeOC6H4TeCH2CH2NHCH(CH3)C6H4-2-OH (L-11) and 2-HO-C6H4-(CH3)CHNHCH2CH2TeCH2CH2NHCH(CH3)C6H4-2-OH (L-12) respectively have been synthesized and studied for ligation behaviour The L9 on reaction with the [Ru(p-cymene)Cl-2](2) results in [Ru(p-cymene)(4-MeOC6H4-TeCH2CH2NH2)Cl]Cl-H2O whereas in the reaction of L-10 with [Ru(p-cymene) Cl-2](2), p-cymene ligand is lost resulting in [RuCl(L-10-H)]. The recent developments, particularly designing of L-1 to L-12 and their ligand chemistry, are reviewed ill the present paper.