The dinuclear complex [Pd(mu-Cl)(C6H4-PPh2C(H)COCH2PPh3)](2)(ClO4)(2) reacts with Hg(OOCCH3)(2) (1:1 molar ratio, CH2Cl2, room temperature) giving the trinuclear derivative [Pd2Hg(mu-Cl)(2)(C6H4-2-PPh2C(H)COC(H)PPh3)(2)](ClO4)(2) (1) The X-ray structure of 1 has been determined: C78H62Cl4HgO10P4Pd2, monoclinic, I2/a, a = 20.205(3) Angstrom, b = 11.7529(9) Angstrom, c = 30.905(3) Angstrom, beta = 90.333(10)degrees, V = 7339.0(14) Angstrom(3), Z = 4. The structure shows two Pd atoms bridged by two Cl atoms and also shows weak Pd-Hg contacts. Both orthometalated ylide groups [C6H4-2-PPh2C(H)COC(H)(PPh3)](-) in 1 act as C,C,C-tridentate ligands, coordinated to the palladium center through the arylic carbon atom and the ylidic carbon atom adjacent to the PPh2 group and to the mercury center through the ylidic carbon atom adjacent to the PPh3 group. The reaction of [Pd(mu-Cl)(C6H4-2-PPh2C(H)COCH2PPh3)](2) (ClO4)(2) with (acac)AuPPh3 (acac = acetylacetonate; 1:2 molar ratio) affords [Pd(C6H4-2-PPh2C(H)COCH2PPh3)(acac-O,O')](ClO4) (2) by transmetalation of the acac group. Further treatment of 2 with (acac)AuPPh3 gives the dinuclear derivative [Pd(C6H4-2-PPh2C(H)COCH(AuPPh3)(PPh3))(acac-O-O')](ClO4) (3) in which the orthometalated ylide fragment acts as a C,C,C-tridentate ligand. The reaction of [Pd(C6H4-2-PPh2C(H)COCH2PPb3)Cl(PPh3)](ClO4) with NBu4OH (1:1 molar ratio) affords [Pd(C6H4-2-PPh2C(H)COCH=PPh3)Cl(PPh3)] as a mixture of the cis and trans isomers (4a/4b), while the reaction of the same cationic precursor [Pd(C6H4-2-PPh2C(H)COCH2PPh3)Cl(PPh3)](ClO4) with (acac)AuPPh3 results in the formation of [Pd(C6H4-2-PPh2C(H)COCH(AuPPh3)(PPh3))Cl(PPh3)](ClO4) (5). The reaction of [Pd(C6H4-2-PPh2C(H)COCH2PPh3) (L-L)](ClO4)(2) (L-L = dppe, phen) with Na[N(SiMe3)(2)] (dppe = 1,2-bis(diphenylphosphino)ethane and phen = 1,10-phenanthroline; 1:1 molar ratio, THF, room temperature) results in the formation of the cationic species [Pd(C6H4-2-PPh2C(H)COCH=PPh3)(L -L)](ClO4) (L-L = dppe (6), phen (7)), which contain a free ylidic fragment. Complex 6 reacts with ClAu(tht) (tht = tetrahydrothiophene; 1:1 molar ratio) giving [Pd(C6H4-2-PPh2C(H)COCH(AuCl)(PPh3))(dppe)](ClO4) (8), while [Pd(C6H4-2-PPh2C(H)COCH2PPh3)(phen)](ClO4)(2) reacts with (acac)AuPPh3 (1:1 molar ratio) affording [Pd(C6H4-2-PPh2C(H)COCH(AuPPh3)(PPh3))(phen)](ClO4)(2) (9).