Synthesis and Properties of Organometallic PtII and PtIV Complexes with Acyclic Selenoether and Telluroether Ligands and Selenoether Macrocycles

Abstract

AbstractThe first series of planar dimethyl(selenoether)PtII complexes, [PtMe2L] [L = MeSe(CH2)nSeMe (n = 2 or 3), o‐C6H4(CH2SeMe)2, [8]aneSe2 (1,5‐diselenacyclooctane), or [16]aneSe4 (1,5,9,13‐tetraselenacyclohexadecane)], have been obtained by treatment of [PtMe2(SMe2)2] with L in Et2O solution and characterised by VT 1H, 13C{1H}, 77Se{1H} and 195Pt{1H} NMR spectroscopy, electrospray MS and microanalysis. The corresponding dimethyl(telluroether)PtII complexes do not form under similar reaction conditions. The distorted octahedral [PtMe3I(L)] [L = o‐C6H4(CH2SeMe)2, [8]aneSe2, [16]aneSe4 or MeC(CH2SeMe)3] form as stable complexes in good yield from reaction of PtMe3I with L in refluxing CHCl3 and have been characterised similarly. These all show bidentate selenoether coordination, with fast pyramidal inversion occurring at room temperature. The distorted octahedral coordination environment at PtIV is also confirmed from a crystal structure of [PtMe3I{o‐C6H4(CH2SeMe)2}]. Rare examples of (telluroether)PtIV complexes, [PtMe3I{o‐C6H4(CH2TeMe)2}] and the dinuclear [Me3Pt(μ2‐I)2(μ2‐MeTeCH2TeMe)PtMe3], have also been prepared and characterised similarly (and also by 125Te{1H} NMR spectroscopy). The [8]aneSe2 and [16]aneSe4 species are the first examples of alkyl PtII or PtIV complexes with (macro)cyclic selenoether coordination. Halide abstraction (TlPF6) from [PtMe3I(κ2‐[16]aneSe4)] affords [PtMe3(κ3‐[16]aneSe4)]PF6; a rare example of a cationic PtIV selenoether. The (diselenoether)PtII complexes undergo oxidative addition of MeI to yield the corresponding PtIV species [PtMe3I(diselenoether)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)