1-HALOBENZOTRIAZOLES AS NEW HALOGENATING AGENTS FOR METAL BETA-DIKETONATES

1-Chloro- and 1-bromobenzotriazole were tested as new electrophilic ha logenating agents for gamma-substitution of acetylacetonates. The iner t and less labile acetylacetonates, such as those containing Cr-III, C o-III, Al-III, Fe-III and VOIV, underwent gamma-halogenation leaving a ll the chelate rings intact, whereas the labile chelates of Cu-II, Ni- II, Co-II and Zn-II, apart from undergoing gamma-halogenation, experie nced partial ligand substitution by the benzotriazole moiety to yield a solid dimer, [M(BTA)(Xacac)](2) (X = Cl or Br). Such selective forma tion of a mixed-ligand complex or gamma-halo beta-diketonate can be as cribed to the lability of the substrate chelate and to the strong coor dinating ability of benzotriazole.