Role of anagostic interactions in cycloplatination of telluroethers: Synthesis and structural characterization

Reactions of K2PtCl4 with TeRR' gave complexes of composition [PtCl2(TeRR')(2)] (R/R' = Ph-2(1a), o-tol(2) (1b), Mes2(1c), Ph/Mes (1d), o-tol/Mes (1e)). The complex [PtCl2(TeMes(2))(2)] in refluxing THF afforded a mononuclear cyclometalated complex [PtCl{(CH2C6H2Me2-4,6)TeMes}(TeMes(2))] (2). It tends to remain in equilibrium with a binuclear derivative [Pt(mu-Cl){(CH2C6H2Me2-4,6)TeMes}12 (3) in CDCl3 solution. The complexes Id and le did not undergo cyclometalation reaction under similar reaction conditions. The 2 on treatment with PPh3 gave [PtCl{(CH2C6H2Me2-4,6)TeMes}(PPh3)] (4). All the complexes have been, 3113, 125-re, characterized by elemental analysis and NMR (H-1, P-31, Te-125, Pt-195) spectroscopy. Anagostic interactions have been recognised for facilitation of cyclometalation reactions. The molecular structures of trans[PtCl2(TeMes)(2)] trans-[PtCl2(PhTeMes)(2)] (1d), trans-[PtCl2(o-tolTeMes)(2)] (le), [PtCl{(CH2C6H2Me2-4,6)TeMes}(TeMes(2))] (2) and [PtCl{(CH2C6H2Me2-4,6)TeMes}(PPh3)] (4) have been established unambiguously by single crystal X-ray diffraction analyses. (C) 2015 Elsevier B.V. All rights reserved.