Ein einfacher Weg zur Herstellung von Alkylpalladium‐Verbindungen durch PdO‐Bindungs‐Spaltung in kationischen Bis(ether‐phosphan)palladium(II)1‐Komplexen mit Grignard‐Reagenzien

A Simple Method for the Preparation of Alkylpalladium Compounds by PdO Bond Cleavage in Cationic Bis(etherphosphane)palladium(II) Complexes with Grignard Reagents Herrn Professor Heinrich Nöth zum 65. Geburtstag gewidmet. The bis(chelate) complexes [Pd(P∩O) 2 ][ClO 4 ] 2 ( 3a – e ) react with methylmagnesium chloride with a concomitant cleavage of two weak PdO bonds to give the methyl complexes trans 1‐ClPd(P∼O) 2 (CH 3 ) ( 4a – e ) (P ∼ O; η 1 ‐ P 1‐coordinated; P∩O: η 2 1‐O, P 1‐chelated; Scheme 1). Diffusion of pentane into the reaction mixture of 4a–e in the presence of the formed magnesium salts yields the cationic complexes trans ‐[Ch 3 Pd(P∼O)1‐(P∩O)][ClO 4 ] ( 6a, c ). The reaction of 3a–e with benzylmagnesium chloride affords the cationic benzyl complexes cis ‐[PhCh 2 Pd(P∼O)(P∩O)][ClO 4 ] ( 8a–e ) in which only one PdO bond has been cleaved. In the presence of carbon monoxide 4a–e adn 6a, c are transformed into the corresponding acyl complexes CH 3 C(O)Pd(P∼O) 2 Cl ( 5a–e and [CH 3 C(O)Pd‐(P∼O)(P∩O)][ClO 4 ] ( 7a, c ). Whereas at 183 K variable‐temperature 31 P{ 1 H}1‐NMR measurements of 6a, c, 7a, c indicate a non‐rigid behavior of the two differently bound ether‐phosphanes, the dynamic process is frozen out for 8a–e . By a lineshape analysis of the spectra the thermodynamic parameters Δ G ≢, Δ H ≢, and Δ S ≢ are obtained. According to a crystal structure analysis 3d and 6c crystallize in the monoclinic space group P 2 1 / c with Z4.