The cyclopalladation of 1 ,l'-azonaphthalene (= di(naphtha1en-I -yl)diazene; 2) with bis(hexafluoroacety1-acetonato)palladium(II) (3; [Pd(hfa),]) yields the ortho-palladated complex (1,1,1,5,5,5-hexafluoropentane-2,4-dionato-fc20,0')[i -(naphthalen-l-ylaro-~~2)naphthalen-2-yl-~Cz]palladium(II) (4) as well as the peri-palladated complex (1,1,1,5,5,5-hexafluoropentane-2,4-d~onato-~~0,O)[8-(naphthalen-l-ylazo-~~~)naphthalen-l-yl-~C']-palladium(I1) (5); their structures were corroborated by X-ray analyses. The formation of the novel peri-metallated product 5 containing a six-membered palladacycle strongly depends upon the reaction conditions.Introduction. -The cyclometallation reaction -albeit described for the first time some 25 years ago [l] [2] -still has an enormous potential as a synthetic tool when employed for the ortho-functionalization of suitable arenes [3 -81. Only recently, cyclopalladated complexes were described that catalyze the Heck olefination [9] or aryl-coupling reactions [lo] in homogeneous solution with high turnover numbers. Other cyclopalladated complexes exhibit some promising liquid-crystalline [ l l -131 or photochemical and electrochemical [14-161 properties. The cyclometallation principle can also be applied effectively to the laboratory-scale syntheses of dyestuff molecules and dyestuff precursors [17].Whereas the papers on investigations of the C-H activation at phenylic ortho-positions 'are copious, far less has been reported on the cyclometallation of naphthalene moieties so far [6][18-281, despite the fact that the naphthalene ring is more reactive towards electrophilic cyclometallating agents. Furthermore, naphthalenes with donorbearing substituents at C( 1) offer both the ortho-and the peri-position for the cyclometallation.To make 1-substituted naphthalenes like naphthalen-1-amine (1) amenable to cyclopalladation, they have to be converted into suitable donor-bearing cyclometallands, as, e.g., the corresponding 1 ,If-azonaphthalene (= di(naphtha1en-1-y1)diazene ; 2). Transforming the original naphthalen-1-amine (1) into the symmetrical 1 ,l'-azonaphthalene (2) has several advantages: this cyclometalland is providing a donor atom for each of the two naphthalene moieties, and the desired functional groups can be introduced into both rings by two separate metallation/cleavage sequences. Finally, the bis-ortho-substituted azonaphthalene would yield two identical ortho-functionalized naphthalen-1-amines upon complete reduction of the azo bridge.The cyclopalladation of the unsubstituted 1 ,l'-azonaphthalene (2) is expected to occur at the C(2) center ortho to the azo bridge, as was shown earlier for various 1 -(phenylazo)naphthalenes [26] [27]. There, the naphthalene peri-position (C(8)) was only