Coordination of donor-functionalized cyclopentadienyl ligands at platinum(II) centers: Syntheses and molecular structure of [μ-(1,2-η²:5,6-η²-cod) {(η⁵-C₅Me₄CH₂CH₂ NMe₂)MePt}₂]

The syntheses of novel monomeric and dimeric platinum(II) complexes are reported. Modified cyclopentadienyls (Cp^R) such as pentamethylcyclopentadienyl (Cp*) and its functionalized derivatives 1-[2-(dimethylamino)eth-1-yl]-2,3,4,5-tetramethylcyclopentadienyl (Cp*^N), 1-(but-3-en-1-yl)-2,3,4,5-tetramethylcyclopentadienyl (Cp*²⁼) and 1-(pent-4-en-1-yl)-2,3,4,5-tetramethylcyclopentadienyl (Cp*³⁼) were reacted with [(η⁴-cod)PtMeX] (COD = cis,cis-1,5-cyclooctadiene, X = halogen) to give the monomeric species [(1,2-η²:5,6-cod)(η⁵-Cp^R)MePt] (Cp^R = Cp* (1), Cp*^N (3), Cp*²⁼ (5), Cp*³⁼ (6)), wherein the COD ligand is η²-coordinated to one metal center. Dimerization of 1 or 3 resulted in the COD-bridged species [μ-(1,2-η²:5,6-η²-cod){(η⁵- Cp^R)MePt}₂] (2, 4); the molecular structure of 4 determined by single-crystal X-ray diffraction. All new compounds were characterized by ¹H, ¹³C, and ¹⁹⁵Pt NMR spectroscopy and by elemental analysis where possible.