Palladium and half sandwich ruthenium(II) complexes of selenated and tellurated benzotriazoles: Synthesis, structural aspects and catalytic applications

Abstract

1-(Phenylselenomethyl)-1 H-benzotriazole ( L 1 ) and 1-(4-methoxyphenyltelluromethyl)-1 H-benzotriazole ( L 2 ) have been synthesized by reacting 1-(chloromethyl)-1H-benzotriazole with in situ generated nucleophiles PhSe − and ArTe −, respectively. The complexes of L 1 and L 2 with Pd(II) and Ru(II)(η 6- p-cymene) have been synthesized. Proton, carbon-13, Se-77 and/or Te-125 NMR spectra authenticate both the ligands and their complexes. The single crystal structures of L 1 , L 2 and [RuCl(η 6- p-cymene)( L)][PF 6] ( L = L 1 : 3, L = L 2 : 4) have been solved. The Ru–Se and Ru–Te bond lengths have been found 2.4801(11) and 2.6183(10) Å, respectively. The palladium complexes, [PdCl 2( L)] ( L = L 1 : 1, L = L 2 : 2) have been explored for Heck and Suzuki–Miyaura C–C coupling reactions. The TON values are upto 95,000. The Ru-complexes have been found promising for catalytic oxidation of alcohols (TON ∼ 7.8–9.4 × 10 4). The complexes of telluroether ligands are as efficient catalysts as those of selenoether ones and in fact better for catalytic oxidation.