Author(s) |
Chauhan, R. S.; Kedarnath, G.; Wadawale, A.; Munoz-Castro, A.; Arratia-Perez, R.; Jain, V. K.; Kaim, W. |
Treatment of toluene solutions of the ditellurides
[Te2{C5H3N(R)-32] (R = H or Me) with
[Pt(PPh3)4] yielded two types of complexes,
[Pt{2-Te-3-(R)C5H3N2(PPh3)2]
(1a-d) as the major products and
[Pt{2-Te-3-(R)C5H3N}2Te(PPh3)]
(2a-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-vis, NMR
(1H and 31P), and (in part) XPS spectroscopy The molecular
structures of [Pt(2-Te-C5H4N)2Te(PPh3)]
(2a) and [Pt{2-Te-C5H3(Me)N}2Te(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 tellunum atoms. The tellurium(0) atom adopts a
"bent T" configuration as it is bridging the 2-Te-C5H3(R)N molecules via N-Te-N bonds (166°
angle) and coordinates to PtII in the trans position to
PPh3. The novel bis(pyridine)tellunum(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. |