A SIMPLE METHOD FOR THE PREPARATION OF ALKYLPALLADIUM COMPOUNDS BY PD-O BOND-CLEAVAGE IN CATIONIC BIS(ETHERPHOSPHANE)PALLADIUM(II) COMPLEXES WITH GRIGNARD-REAGENTS

The bis(chelate) complexes [Pd(P and O)2][ClO4]2 (3a-e) react with met hylmagnesium chloride with a concomitant cleavage of two weak Pd-O bon ds to give the methyl complexes trans-ClPd(P is similar to O)2(CH3) (4 a-e) (P is similar to O: eta1-P-coordinated; P and O: eta2-O,P-chelate d; Scheme 1). Diffusion of pentane into the reaction mixture of 4a-e i n the presence of the formed magnesium salts yields the cationic compl exes trans-[CH3Pd(P is similar to O)(P and O)][ClO4] (6a, c). The reac tion of 3a-e with benzylmagnesium chloride affords the cationic benzyl complexes cis[PhCH2Pd(P is similar to O)(P and O)][ClO4] (8a-e) in wh ich only one Pd-O bond has been cleaved. In the presence of carbon mon oxide 4a-e and 6a, c are transformed into the corresponding acyl compl exes CH3C(O)Pd(P is similar to O)2Cl (5a-e) and [CH3C(O)Pd(P is simila r to O)(P and O)][ClO4] (7a, C). Whereas at 183 K variable-temperature P-31{H-1}-NMR measurements of 6a, c, 7a, c indicate a non-rigid behav ior of the two differently bound ether-phosphanes, the dynamic process is frozen out for 8a-e. By a line-shape analysis of the spectra the t hermodynamic parameters DELTAG(not-equal), DELTAH(not-equal), and DELT AS(not-equal) are obtained. According to a crystal structure analysis 3d and 6c crystallize in the monoclinic space group P2(1)/c with Z = 4 .