Synthesis of mercury(II) and palladium(II) organometallic derivatives of terephthaldehyde by metalation, transmetalation, oxidation, and condensation reactions. X-ray crystal structures of trans-[PdCl{C6H3(CO2H)(2)-2,5}(PPh3)(2)]center dot Me2CO center dot 2MeOH, trans-[PdCl{C6H3(CHO)-2-(CO2H)-5}(PPh3)(2)]center dot 2CH(2)Cl(2), and [Pd{C6H3(CH=NC6H4NH2-4)-2-(CHO)-5}(N,N,N',N'-tetramethylethylenediamine)]CF3SO3. Molecular assemblies through [Pd]-Cl center dot center dot center dot HO2C-aryl and [Pd]-Cl center dot center dot center dot HOMe HO(O)C-aryl hydrogen bonds

The organomercurials [HgCl{C6H3(CHO)(2)-2,5}] (1) and [Hg(C6H3(CHO)(2)-2,5}(2)] (2) have been prepared by mercuriation of terephthaldehyde. Palladium complexes [PdCl{C6H3-(CHO)(2)-2,5}(N-N)] (N-N = N,N,N',N'-tetramethylethylenediamine (tmeda) (3) or 2,2'-bipyridine (bpy) (3')) or trans-[PdCl{C6H3(CHO)(2)-2,5}(PPh3)(2)]. H2O (4) have been obtained by reacting (Me4N)(2)]Pd2Cl6] or trans-[PdCl2(PPh3)(2)], respectively, with 1 or 2. The reaction of potassium permanganate with complexes 3 and 3' or mercurial 1 results in the selective oxidation of the 5-formyl substituent affording [PdCl{C6H3(CHO)-2-(CO2H)-5}(N-N)] (N-N = tmeda (5), bpy (5')) or, respectively, a mixture whose major component is the fully oxidized [HgCl{C6H3(CO2H)(2)-2,5}] (7) or a mixture of isomers [HgCl{C6H3(CHO)-2-(CO2H)-5}]/[HgCl-{C6H3(CO2H)-2-(CHO)}] (8a/8b) depending on the molar ratio of the reagents. The reaction of mixtures containing 7 or 8 with trans-[PdCl2(PPh3)(2)] give pure trans-[PdCl{C6H3(CO2H)(2)-2,5}(PPh3)(2)] (9) or trans-[PdCl{C6H3(CHO)-2-(CO2H)-5}(PPh3)(2)] (10), respectively. Complexes 3 and 3' react with amines and NaClO4 . H2O or Tl(CF3SO3) to give, depending of the reaction conditions, cyclopalladated derivatives [Pd{C6H3(CH=NR)-2-(CH=NR)-5)(N-N)](+) or [Pd-{C6H3(CH=NR)-2-(CHO)-5}(tmeda)](+). The mercurial 1 reacts with hydroxylamine to give the mercuriated oxime [HgCl{C6H3(CH=NOH)(2)-2,5}] (14), which reacts with (Me4N)(2)[Pd2Cl6] to give the cyclopalladated complex [Pd{C6H3(CH=NOH)-2-(CH=NOH)-5)(mu-Cl)](2) (15). From 15 some derivatives have been prepared. Complex 3 reacts with NH2OMe to give [Pd{C6H3(CH=NOMe)-2-(CH=NOMe)-5}(tmeda)]ClO4 (19). The imine C6H4(CH=NTo)(2)-1,4(To = C6H4Me-4) reacts with palladium(II) acetate to give the dipalladated imine [Pd{C6H2-(CH=NTo)-2-(Pd(mu-OAc)}-4-(CH-NTo)-5}(mu-OAc)](n) (20). Hydrolysis of 20 in the presence of potassium bromide and bpy results in the formation of [C6H2{PdBr(bpy)}(2)-1,4-(CHO)(2)-2,5] (21), from which [C6H2{Pd(PPh3)(bpy>}(2)-1,4-(CHO)(2)-2,5](CF3SO3)(2) (22) can be prepared. The structures of 9 . Me2CO . 1.5MeOH, 10 . 2CH(2)Cl(2) and [Pd{C6H3(CH=NR)-2-(CHO)-5}(tmeda)]CF3SO3 (R = C6H4NH2-4) (12c') have been determined by X-ray crystallography.