Formation and coordination modes of the C4E4 moiety (E = COOMe) bound to two palladium(II) moieties

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 40; no. 10; pp. 2383 - 2387
• Main Authors: Murahashi, Tetsuro, Okuno, Taketoshi, Usui, Kentaro, Takase, Kohei, Otani, Toshiaki, Ogoshi, Sensuke, Kurosawa, Hideo
• Format: Journal Article
• Language: English
• Published: England 01.01.2011
• Subjects: Acetonitrile; Bonding; Crystallography; Dienes; Insertion; Ligands; Palladium; X-rays
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c0dt01169j

The transmetallation of the palladacyclopentadiene complex Pd{C(COOMe)C(COOMe)C(COOMe)C(COOMe)}(bipy) with the dicationic Pd(II) complex [Pd(bipy)(CH(3)CN)(2)][BF(4)](2) afforded a terminally σ-palladated diene complex [Pd(2){μ-η(1):η(1)-C(COOMe)C(COOMe)C(COOMe)C(COOMe)}(bipy)(2)(CH(3)CN)(2)][BF(4)](2). It was revealed by X-ray crystallographic analysis that replacement of the acetonitrile ligands in a terminally σ-palladated diene complex with PPh(3) ligands resulted in the conformation change of the σ-palladated diene moiety from skewed s-cis to planar s-trans. Treatment of a bis-triphenylphosphine dipalladium complex [Pd(2)(PPh(3))(2)(CH(3)CN)(4)][PF(6)](2) with dimethoxyacetylene dicarboxylate (DMAD) (1 equiv.) in acetonitrile resulted in the insertion of DMAD to the Pd-Pd bond to afford [Pd(2){μ-η(1):η(1)-C(COOMe)C(COOMe)}(PPh(3))(2)(CH(3)CN)(4)][PF(6)](2). Addition of the second DMAD gave the ylide-type complex [Pd(2){μ-η(2):η(3)-C(COOMe)C(COOMe)C(COOMe)C(COOMe)(PPh(3))}(PPh(3))(2)(CH(3)CN)(3)][PF(6)](2) of which the structure was determined by X-ray crystallographic analysis.