Tellurated Schiff Bases Formed from {2‐[(4‐Methoxyphenyl)telluro]ethyl}amine and Bis(2‐aminoethyl) Telluride with o‐Hydroxyacetophenone: Synthesis and Complexation Reactions with HgII, PdII and RuII − Crystal Structures of the Ligands, [Ru(p‐cymene)Cl{H2NCH2CH2TeC6H4‐4‐OCH3}]Cl·H2O and [RuCl{4‐MeOC6H4TeCH2CH2NHCH(CH3)C6H4‐2‐O−}

Abstract

Abstract{2‐[(4‐Methoxyphenyl)telluro]ethyl}amine and bis(2‐aminoethyl) telluride on treatment with o‐hydroxyacetophenone gave the Schiff bases 4‐MeOC6H4TeCH2CH2N=C(CH3)C6H4‐2‐OH (L1) and 2‐HOC6H4(CH3)C=NCH2CH2TeCH2CH2N=C(CH3)C6H4‐2‐OH (L3), respectively. The reduction of L1 and L3 with NaBH4 resulted in 4‐MeOC6H4TeCH2CH2NHCH(CH3)C6H4‐2‐OH (L2) and 2‐HOC6H4(CH3)CHNHCH2CH2TeCH2CH2NHCH(CH3)C6H4‐2‐OH (L4), respectively, which have 1 or 2 chiral centers. The 1H and 13C NMR spectra of L1 to L4 were found to be characteristic. Treatment of L1 with [Ru(p‐cymene)Cl2]2 resulted in [Ru(p‐cymene)(4‐MeOC6H4TeCH2CH2NH2)Cl]Cl·H2O (1) whereas in the reaction of L2 with [Ru(p‐cymene)Cl2]2, the p‐cymene ligand is lost resulting in [RuCl(L2‐H)] (4). The reactions of L1, L3 and L4 with HgBr2 resulted in complexes of the type [HgBr2·(L)2] while Na2PdCl4 reacted with L1 to give [PdCl(L1‐H)]. The solid‐state structures of L1, L3, 1 and 4 were determined by single‐crystal X‐ray diffraction studies. The very swift formation of the tellurated amine from a tellurated Schiff base (L1) by hydrolysis has been observed for the first time and has resulted in 1. The Ru−N and Ru−Te bond lengths in 1 are 2.142(3) and 2.6371 (4) Å, respectively. The replacement of the p‐cymene ligand with a hybrid organotellurium ligand (L2‐H), resulting in 4, is also a first example of its kind. The Ru center in 4 has a square‐planar geometry, with the Ru−N, Ru−Te, Ru−O and Ru−Cl bond lengths being 2.041(6), 2.4983(8), 2.058(5) and 2.308(2) Å, respectively. In the crystals of 4 there are secondary intermolecular Te···Cl interactions and intermolecular N−H···O hydrogen bonds. This is the first example in which coordinated Te in a complex is engaged in two intermolecular secondary interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)