Ru2(CO)4(OOCR)2(PPh3)2 sawhorse-type complexes containing ?2-?2-carboxylato ligands derived from biologically active acids

The thermal reaction of Ru3(CO)12 with the biol. active acids acetyl salicylic acid (Aspirin), ?-methyl-4-(isobutyl)phenylacetic acid (Ibuprofen) and 3?,7?,12?-trihydroxy-5?-cholanic acid (cholic acid) in refluxing THF, followed by addn. of PPh3, gives the dinuclear complexes Ru2(CO)4(OOCR)2(PPh3)2 (1: R = C6H4-2-OCOMe, 2: R = CHMe-C6H4-4-Bui, 3: C23H39O3). The single-crystal structural anal. of 1 and 2 reveals a dinuclear Ru2(CO)4 sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two phosphine ligands occupy the axial positions at the Ru atoms. However, chiral C atoms in the carboxylic acid undergo racemization during the thermal reaction. [on SciFinder(R)]