191285-18-4Relevant academic research and scientific papers
Hybrid (Te,O) ligands 2-(phenyltelluromethyl)tetrahydro-2H-pyran (L1) and 2-(2-{4-methoxyphenyl}telluorethyl)-1,3-dioxane (L2), and their palladium(II) and platinum(II) complexes
Batheja, Raman,Singh, Ajai K.
, p. 2509 - 2516 (1997)
The nucleophilic reaction of in situ generated [ArTe-] with appropriate organic halides has been used to synthesize 2-(phenyrtelluromethyl)-tetrahydro-2H-pyran (L1) and 2-(2-{4-methoxyphenyl}telluorethyl-1,3-dioxane (L2). Their complexes with stoichiometries [MCl2(L)2],[M(L)2](ClO4) 2, [M(DPPE)(L)2](ClO4)2, [M(PPh3)2(L)2](ClO4)2 and [M(phen)(L)2](ClO4)2 [where M = Pd11 or Pt11; L = L1 or L2, DPPE = 1,2-bis(diphenylphosphino)ethane], have been synthesized. Molecular weight, conductance measurements, IR, UV-visible, 1H, 125Te-{1H} and 31P-{1H} NMR spectra have been used to characterize L1, L2 and their complexes. Ligation of the two (Te,O) ligands, in all the complexes, except [M(L)2](ClO4)2, is in the monodentate mode through tellurium only. [PtCl2(L)2]-type complexes exist in solution as a mixture of cis and trans isomers, the latter being present in very high abundance. The complexes [PdCl2(L)2] exhibit only one v(Pd - Cl) between 340 and 350 cm-1, consistent with a trans structure. The 1J(Pt - Te) values (658-704 Hz) in the 125Te NMR spectra of [Pt(L)2](ClO4)2 and [Pt(PPh3)2(L)2](ClO4)2 correspond to trans structures, which are supported in the second type of complexes by 1J(Pt - P) (ca 3000 Hz). The 31P NMR spectral data indicate that the mixed ligand complexes of Pd11 and Pt11containing PPh3 and DPPE are isostructural. The chelate shifts in the 125Te NMR spectra have been found to be large and positive (113-127 ppm) when five-membered chelate rings are formed, but for six-membered chelation the shift is small and negative (-15 to 19 ppm). The quenching of 1O2 by [Pd(phen)(L)2](ClO4)2 has been observed.
