Synthesis of terminal and bridging acetonyl complexes of palladium(II). Crystal structures of [{(AsPh3)(C6F5)Pd}(2)(mu-CH2C(O)CH3)(2)], [(AsPh3)(CsF5)Pd{CH2C(O)CH3)(t-BuNC)], and [(o-C6H4CH2NMe2)Pd(O,O '-CH(CO2Et)2}]

The reaction of the palladium-hydroxo complex [((o-C6H4CH2NMe2)Pd)(2)(mu -O H)(2)] with acetone leads to the formation of the bridging O,C-acetonyl com plexes [{(o-C6H4CH2NMe2)Pd}(2)(mu -OH){mu -CH2C(O)CH3}] (1) and [{(o-C6H4CH 2NMe2)Pd}(2){mu -CH2C(O)CH3}(2)] (2), The reaction (1:2 molar ratio) of [{( AsPh3)(C6F5)Pd}(2)(mu -Cl)}(2)] with 20% aqueous [NBu4]OH in acetone yields [{(AsPh3)(C6F5)Pd}(2){mu -CH2C(O)CH3}(2)] (3), The reaction (1:1 ratio) be tween 2 or 3 and t-BuNC gives the monomeric complexes [(o-C6H4CH2NMe2)Pd{CH 2C(O)Me}(t-BuNC)] (4) and [(AsPh3)(C6F5)Pd{CH2C(O)CH3)(t-BuNC)] (5). Heatin g an acetone solution of [NBu4](2)[{(C6F5)(2)Pd](2)(mu -OH)(2)] gave the 2, 4-dimethyl-1-oxapenta-1,3-dienyl palladium complex [NBu4][(C6F5)(2)Pd(eta ( 5)-2,4-Me-2-C4H3O)] (6). The reaction of [{(o-C6H4CH2NMe2)Pd}(mu -OH)(2)] w ith CH2(CO2R)(2) (R = Et, Me) leads to [(o-C6H4CH2NMe2)Pd{O,O ' -CH(CO2R)(2 )}] (7, R = Me; 8, R = Et), The crystal structures of 3, 5, and 8 have been established by X-ray diffraction studies. The structure of 3 shows the C,O -enolate anion bridging two palladium atoms with a head-to-tail arrangement . In the monomeric complex 5 the C-bound acetonyl is trans to triphenylarsi ne, In 8 the diethyl malonate ligand and the palladium atom form a six-memb ered chelate ring.