Treatment of toluene solutions of the ditellurides [Te(2){C(5)H(3)N(R)-3}(2)] (R = H or Me) with [Pt(PPh(3))(4)] yielded two types of complexes, [Pt{2-Te-3-(R)C(5)H(3)N}(2)(PPh(3))(2)] (1a-d) as the major products and [Pt{2-Te-3-(R)C(5)H(3)N}(2)Te(PPh(3))] (2a-d) as minor products. The above complexes can also be obtained by the reaction of [PtCl(2)(PR'(3))(2)] (PR'(3) = PPh(3) or PPh(2)(2-C(5)H(4)N)) with 2 equiv of Na(2-Te-C(5)H(3)R). The complexes were characterized by elemental analyses and UV-vis, NMR ((1)H and (31)P), and (in part) XPS spectroscopy. The molecular structures of [Pt(2-Te-C(5)H(4)N)(2)Te(PPh(3))] (2a) and [Pt{2-Te-C(5)H(3)(Me)N}(2)Te(PPh(3))] (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-C(5)H(3)(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- C(5)H(3)(R)N molecules via N-Te-N bonds (166 degrees angle) and coordinates to Pt(II) in the trans position to PPh(3). The novel bis(pyridine)tellurium(0) arrangement resembles the bis(pyridine)iodonium structure. The calculated NICS indices and ELF functions clearly show that the compounds 2a and 2b are aromatic in the region defined by the Te-C-N-Te-Pt five-membered rings.

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Oxidative addition reaction of dipyridyl ditellurides to [Pt2(dppm)3] gave two types of complexes, [Pt­{2-Te-C5H3(3-R)­N}2(dppm)] (1) and [Pt­{PPh2C­(TeC5H3(3-R)­N)2PPh2}2] (2) (R = H or Me), in ∼65 and ∼20% yield, respectively. Both these complexes are also formed in the substitution reaction between [PtCl2(dppm)] and NaTeC5H3(3-R)­N. Treatment of [Pt­(dppe)2] with dipyridyl ditellurides yielded an oxidative addition product, [Pt­{2-Te-C5H3(3-R)­N}2 (dppe)] (3) (R = H or Me), exclusively. In a substitution reaction of [PtCl2(dppe)] with NaTeC5H3(3-Me)­N a complex of composition Pt­{TeC5H3(3-Me)­N}­(dppe)­Cl (4) was formed. The reaction between either [Pt­(dppp)2] and Te2(C5H3(3-Me)­N)2 or [PtCl2(dppp)] and NaTeC5H3(3-R)N afforded a mixture of [Pt­{2-Te-C5H3(3-Me)­N}2(dppp)] (5) and [Pt3Te2(dppp)3]2+ (6), which were separated by column chromatography. All the complexes were characterized by elemental analyses and NMR (1H, 31P, 195Pt) spectroscopy. The molecular structures of [Pt­{PPh2C­(TeC5H4N)2PPh2}2] and [Pt2{TeC5H3(3-Me)­N}2(dppe)2]­[BPh4]2 were established by single-crystal X-ray diffraction analyses. The bonding, charge transfer, and geometry of compounds [Pt­{2-Te-C5H3(3-R)­N}2(dppm)] (1), [Pt­{PPh2C­(TeC5H3(3-R)­N)2PPh2}2] (2), and [Pt3Te2(dppp)3]2+ (6) have been analyzed through relativistic density functional calculations.

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Arylselenolate-based copper complexes have been synthesized and used as pre-catalysts for azide-alkyne cycloaddition reactions.