2-[2-(4-Methoxyphenyltelluro)ethyl]thiophene ( L1) bis[2-(2-thienyl)ethyl] telluride ( L2) and their metal complexes; crystal structure of trans-dichlorobis{2-(2-(4-methoxyphenyltelluro)ethyl)thiophene-Te}palladium(II) and {bis[2-(2-thienyl)ethyl] telluride}dichloro( p-cymene)ruthenium(II)

Abstract

The reaction of ArTe − (Ar=4-MeOC 6H 4) and Te 2− generated in situ by borohydride reduction of Ar 2Te 2 and Te, respectively, with 2-(2-thienyl)ethyl chloride has resulted in 2-[2-(4-methoxyphenyltelluro)ethyl]thiophene ( L 1 ) and bis[2-(2-thienyl)ethyl] telluride ( L 2 ), respectively. Their complexes [AgNO 3( L 1 )] ( 1) [PdCl 2( L 1 ) 2] ( 2) [PtCl 2( L 1 ) 2] ( 3) [HgBr 2( L 1 )] 2 ( 4) [Ru( p-cymene)Cl 2( L 1 )] ( 5) [Ru( p-cymene)Cl 2( L 2 )] ( 6) and [PdCl 2( L 2 ) 2] have been synthesized. The ligands and complexes exhibit characteristic 1H and 13C{ 1H} NMR spectra. Both the ligands coordinate only through Te in all the complexes. The single crystals of 2 and 6 are characterized by X-ray diffraction. Compound 2 has square planar geometry around Pd and trans arrangement of ligands. The Pd–Te bond distances 2.5951(7) and 2.5872(7) Å are longer than the values expected due to strong trans influence. The unique intermolecular secondary Te⋯Cl interaction (distance=3.450/3.449 Å) between neighbouring molecules has been observed in the crystal structure of 2. The distance between Pd atoms of two neighbouring molecules 3.2143(10) Å has also been found less than the sum of van der Waal's radii 3.26 Å. These secondary interactions in 2 result in the formation of a dimeric species, which remains intact even in the solution. Compound 6 is a half sandwich having three coordination sites occupied by two Cl atoms and the Te atom of L 2 with Ru–Te bond distance of 2.6528(9) Å and Ru–Cl, 2.415(2)/2.422(2) Å.