Département de chimie moléculaire

Nickel(II) and cobalt(II) bis(phenolate)-dipyrrin complexes [I; M = Ni (1), Co (2)] were prepd. in 80-84{%} yields by reaction of the ligand H3L with the corresponding metal acetate in MeOH/CHCl3. Treating 1 and 2 with AgSbF6 gave the cationic compds. 1+SbF6- and 2+SbF6-, resp., and the structures of all 4 compds. were detd. by x-ray crystallog. Combined XRD and spectroscopic techniques and theor. calcns. showed that the oxidative redox processes occur at the ligand and not at the metal center in Ni2+ and Co2+ complexes contg. the L3- ligand, to give M2+-L.bul.2- and M2+-Lox-. Full delocalization of the SOMO gives the ligand an unprecedented hybrid porphyrinyl-phenoxyl radical character and a highly stable L.bul.2- form. Also, both the extensive conjugation and neg. charge of L3- greatly facilitate oxidn. of the complexes, an oxidn. that is more facile than that of salen and porphyrin complexes. [on SciFinder(R)]