Reactivity of Dipyridyl Ditellurides with (Diphosphine)Pt0 and 2-Pyridyltellurolates with (Diphosphine)PtCl2 and Isolation of Different Structural Motifs of Platinum(II) Complexes

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.