PALLADIUM A-FRAME COMPLEXES CONTAINING CARBOXYLATO LIGANDS - SYNTHESIS OF [PD2(O2CR)2(MU-C2(CO2ME)2)(MU-PH2PCH2SCH2PH)2] AND NMR EVIDENCE OF THE ENANTIOTOPIC FACE IN THE SIDE-BY-SIDE COMPLEX [PD2CL2(MU-PH2PCH2SCH2PH)2]

The A-frame complex [Pd2Cl2{mu-C2(CO2Me)2}(mu-Ph2PCH2SCH2Ph)2], obtained by the reaction between the side-by-side complex [Pd2Cl2(mu-Ph2PCH2SCH2Ph)2] (1) and dimethyl acetylenedicarboxylate, reacts with silver acetate and silver benzoate to give [Pd2(O2CR)2{mu-C2(CO2Me)2}(mu-Ph2PCH2SCH2Ph)2].3H2O [R = Me (3), Ph (4)]. Similar reactions with silver salts of (S)- and racemic-2-phenylpropionic acid afford [Pd2(O2 CHMePh)2{mu-C2(CO2Me)2}(mu-Ph2PCH2SCH2Ph)2] [(S)- (5), racemic- (6)]. The NMR spectra of 5 and 6 show diastereoisomeric signal splitting, elucidating the presence of the enantiotopic face in 1.