Routes to unique palladium A-frame complexes with a bridging fluoro-ligand

Braun T, Steffen A, Schorlemer V, Neumann B, Stammler H-G. Routes to unique palladium A-frame complexes with a bridging fluoro-ligand. DALTON TRANSACTIONS. 2005;(20):3331-3336.Treatment of a toluene solution of [PdMe2(Cy2PCH2PCy2)] ( 1) with pentafluoropyridine in the presence of traces of water affords the generation of the A-frame complexes [(PdMe)(2){mu-kappa(2)(P, P) Cy2PCH2PCy2}(2)(mu-F)][SiMeF4] (2a) and [(PdMe)(2){mu-kappa(2)(P, P) Cy2PCH2PCy2}(2)(mu-F)][OC5NF4] (2b). If the reaction is performed in an NMR tube equipped with a PFA inliner, complex 2b is produced, only. Treatment of 1 with penta fluoropyridine in the presence of an excess water yields the pyridyloxy complex [PdMe(OC5NF4)(Cy2PCH2PCy2)] (3). Compound [(PdMe)(2){mu-kappa(2)(P, P) Cy2PCH2PCy2}(2)(mu-F)][FHF] ( 2c) bearing a bifluoride anion instead of SiMeF4- or OC5NF4- can be generated by reaction of 1 with substoichiometric amounts of Et3N center dot 3HF. The analogous complex [(PdMe)(2){mu-kappa(2)(P, P)Ph2PCH2PPh2}(2)(mu-F)][FHF] ( 5c) has been synthesized by addition of Ph2PCH2PPh2 to a solution of [PdMe2(Me2NCH2CH2NMe2)] ( 4) in THF and subsequent treatment of the reaction mixture with Et3N center dot 3HF. The structure of the A-frame complex 5c has been determined by X-ray crystallography