Article,

Tellurium(0) as a Ligand: Synthesis and Characterization of 2-Pyridyltellurolates of Platinum(II) and Structures of Pt2-Te-3-(R)C5H3N2Te(PR'3) (R = H or Me)

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Inorganic Chemistry, 49 (9): 4179--4185 (2010)
DOI: 10.1021/ic902347s

Abstract

Treatment of toluene solns. of the ditellurides Te2C5H3N(R)-32 (R = H or Me) with Pt(PPh3)4 or PtCl2(PPh2(2-C5H4N))2 yielded two types of complexes, Pt2-Te-3-(R)C5H3N2(PPh3)2 (1a-b) and Pt2-Te-3-(R)C5H3N2(PPh2(2-C5H4N))2 (1c-d) as the major products and Pt2-Te-3-(R)C5H3N2Te(PPh3) (2a-b) and Pt2-Te-3-(R)C5H3N2Te(PPh2(2-C5H4N)) (2c-d) as minor products. The above complexes can also be obtained by the reaction of PtCl2(PR'3)2 (PR'3 = PPh3 or PPh2(2-C5H4N)) with 2 equiv of Na(2-Te-C5H3R). The complexes were characterized by elemental analyses and UV-visible, NMR (1H and 31P), and (in part) XPS spectroscopy. The mol. structures of Pt(2-Te-C5H4N)2Te(PPh3) (2a) and Pt2-Te-C5H3(Me)N2Te(PPh3) (2b) were established by single crystal x-ray diffraction. Both complexes exhibit a distorted square-planar configuration at the platinum(II) centers. The two mutually trans positioned 2-pyridinetellurolate ligands 2-Te-C5H3(R)N coordinate to the central platinum atom in a monodentate fashion through the tellurium atoms. The tellurium(0) atom adopts a bent T configuration as it is bridging the 2-Te-C5H3(R)N mols. via N-Te-N bonds (166° angle) and coordinates to PtII in the trans position to PPh3. The novel bis(pyridine)tellurium(0) arrangement resembles the bis(pyridine)iodonium structure. The calcd. NICS indexes and ELF functions clearly show that the compds. 2a and 2b are arom. in the region defined by the Te-C-N-Te-Pt five-membered rings. on SciFinder(R)

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