Synthesis and single crystal structures of first examples of tridentate ligands of (Te, N, S) type and their complexes with palladium(II), platinum(II) and ruthenium(II)

The First examples of (Te, N, S) type ligands, 2-CH3SC6H4CHNCH2CH2TeC6H4-4-OCH3 (L1) and 2- CH3SC6H4CHNHCH2CH2TeC6H4-4-OCH3 (L2), and their metal complexes, [PdCl(L1)]PF6 · CHCl3 · 0.5H2O (4), [PtCl(L1)]PF6 (5), [PdCl(L2)]ClO4.CHCl3 (6), [PtCl(L2)]ClO4 (7), and [Ru(p-cymene)(L2)](PF6)2 · CHCl3 (8), have been synthesized and characterized. The single crystal structures of 4, 6 and 8 have revealed that both the ligands coordinate in them in a tridentate (Te, N, S) mode. The geometry around Pd in both the complexes has been found to be square planar, whereas for Ru in a half sandwich complex 8, it is found to be octahedral. Between two molecules of 4 there are intra and inter molecular weak Te⋯Cl [3.334(3) and 3.500(3) Å, respectively] interactions along with weak intermolecular Pd⋯Te [3.621(2) Å] interactions. The Pd–Te bond lengths are between 2.517(6) and 2.541(25) Å and the Ru–Te bond length is 2.630(6) Å. The crystal structure of [PdCl2(4-MeO–C6H4– TeCH2CH2NH2)] (9) is also determined. It is formed when KPF6 is not added in the synthesis of 4 and Pd-complex of L1 is recrystallized. Apart from Te⋯Cl secondary interactions, C–H⋯π interactions also exist in the crystal of 9.