Mononuclear anionic octahedral cobalt(III) complexes based on N-salicylidene-o-aminophenol and its derivatives: synthetic, structural and spectroscopic studies.

The reactions of Co(II) sources with N-salicylidene-o-aminophenol (H2saph), N-salicylidene-o-amino-4-methylphenol (H2saph-4Me) and N-salicylidene-o-amino-4-chlorophenol (H2saph-4Cl) were studied in MeOH. The new solid complexes (Bu4(n)N)[Co(III)(saph)2] (1), (Et3NH)[Co(III)(saph-4Me)2]⋅MeOH⋅MeCO2H (2⋅MeOH⋅MeCO2H) and (Et3NH)[Co(III)(saph-4Cl)2]⋅MeOH⋅MeCO2H (3⋅MeOH⋅MeCO2H) have been isolated and their structures determined by single-crystal, X-ray crystallography. The three compounds contain the mononuclear, low- spin octahedral anion [Co(III)L2](-) (H2L=H2saph, H2saph-4Me, H2saph-4Cl), in which both L(2)(-) ligands act as tridentate chelating, meridional ONO donors. The crystal structures of 2⋅MeOH⋅MeCO2H and 3⋅MeOH⋅MeCO2H are built through H-bonding and π-π stacking interactions. The new complexes were characterized by elemental analyses and spectroscopic (IR, Raman, UV/VIS, (1)H NMR) data. All data are discussed in terms of the nature of bonding and known structures.