Cyclopalladated complexes derived from benzamidoxime

Cyclopalladated benzamidoxime complexes [Pd{C,N-C6H4{C(NH2)=NOH}-2}Cl(L)] (L = PTol(3), Tol = C6H4Me-4 (2a); XyNC, Xy = C6H3Me2-2,6 (2b); pic, C5H4Me-4 (2c)), [Pd{C,N-C6H4{C(NH2)=NOH}-2}(L-2)]-ClO4 (L = pic (3a); L-2 = 4,4'-di-tert-butyl-2,2'-bipyridine, tbbpy (3b)) and PPN[Pd{C,N-C6H4{C(NH2)= NOH}-2}Cl-2] (4) are prepared by reacting [Pd{C,N-C6H4{C(NH2)=NOH}-2}(mu-Cl)](2) (1) with the appropriate neutral ligand or with [PPN] Cl, respectively. The cationic complexes are obtained in the presence of NaClO4. The reaction of 2a with (KBuO)-Bu-t affords the dinuclear oximato complex [Pd{mu-C,N, O-C6H4{ C(NH2)=NO}-2}(PTol(3))](2) (5) or, in the presence of ClCH(2)py center dot HCl, the pincer derivative [Pd{C,N,N'-C6H4{ C(NH2)=NOCH2(C5H4N-2)}-2}(PTol(3))]ClO4 (6). Complex 2b reacts with XyNC to give the iminobenzoyl complex [Pd{C,N-C(N=Xy)C6H4{C(NH2)=NOH}-2}Cl(CNXy)] (7) resulting from the insertion of XyNC into the Pd-C bond. The dinuclear complex [{Pd(tbbpy)}(2){C,N,N',O-C6H4{C(NH)=NO}-2}]ClO4 (8) bearing a bridging tetradentate benzimido(oximate) ligand is obtained by reacting Pd(OAc)(2) with tbbpy and the metal-ligand complex 3b. The crystal structures of complexes 2a, 6, 7 and 8 have been determined.